Dissertations / Theses: 'Bio-Interfaces'

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Crescentini, Marco <1984&gt. "Advanced CMOS Interfaces for Bio-Nanosensors." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4660/1/crescentini_marco_tesi.pdf.

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The improvement of devices provided by Nanotechnology has put forward new classes of sensors, called bio-nanosensors, which are very promising for the detection of biochemical molecules in a large variety of applications. Their use in lab-on-a-chip could gives rise to new opportunities in many fields, from health-care and bio-warfare to environmental and high-throughput screening for pharmaceutical industry. Bio-nanosensors have great advantages in terms of cost, performance, and parallelization. Indeed, they require very low quantities of reagents and improve the overall signal-to-noise-ratio due to increase of binding signal variations vs. area and reduction of stray capacitances. Additionally, they give rise to new challenges, such as the need to design high-performance low-noise integrated electronic interfaces. This thesis is related to the design of high-performance advanced CMOS interfaces for electrochemical bio-nanosensors. The main focus of the thesis is: 1) critical analysis of noise in sensing interfaces, 2) devising new techniques for noise reduction in discrete-time approaches, 3) developing new architectures for low-noise, low-power sensing interfaces. The manuscript reports a multi-project activity focusing on low-noise design and presents two developed integrated circuits (ICs) as examples of advanced CMOS interfaces for bio-nanosensors. The first project concerns low-noise current-sensing interface for DC and transient measurements of electrophysiological signals. The focus of this research activity is on the noise optimization of the electronic interface. A new noise reduction technique has been developed so as to realize an integrated CMOS interfaces with performance comparable with state-of-the-art instrumentations. The second project intends to realize a stand-alone, high-accuracy electrochemical impedance spectroscopy interface. The system is tailored for conductivity-temperature-depth sensors in environmental applications, as well as for bio-nanosensors. It is based on a band-pass delta-sigma technique and combines low-noise performance with low-power requirements.

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Crescentini, Marco <1984&gt. "Advanced CMOS Interfaces for Bio-Nanosensors." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4660/.

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The improvement of devices provided by Nanotechnology has put forward new classes of sensors, called bio-nanosensors, which are very promising for the detection of biochemical molecules in a large variety of applications. Their use in lab-on-a-chip could gives rise to new opportunities in many fields, from health-care and bio-warfare to environmental and high-throughput screening for pharmaceutical industry. Bio-nanosensors have great advantages in terms of cost, performance, and parallelization. Indeed, they require very low quantities of reagents and improve the overall signal-to-noise-ratio due to increase of binding signal variations vs. area and reduction of stray capacitances. Additionally, they give rise to new challenges, such as the need to design high-performance low-noise integrated electronic interfaces. This thesis is related to the design of high-performance advanced CMOS interfaces for electrochemical bio-nanosensors. The main focus of the thesis is: 1) critical analysis of noise in sensing interfaces, 2) devising new techniques for noise reduction in discrete-time approaches, 3) developing new architectures for low-noise, low-power sensing interfaces. The manuscript reports a multi-project activity focusing on low-noise design and presents two developed integrated circuits (ICs) as examples of advanced CMOS interfaces for bio-nanosensors. The first project concerns low-noise current-sensing interface for DC and transient measurements of electrophysiological signals. The focus of this research activity is on the noise optimization of the electronic interface. A new noise reduction technique has been developed so as to realize an integrated CMOS interfaces with performance comparable with state-of-the-art instrumentations. The second project intends to realize a stand-alone, high-accuracy electrochemical impedance spectroscopy interface. The system is tailored for conductivity-temperature-depth sensors in environmental applications, as well as for bio-nanosensors. It is based on a band-pass delta-sigma technique and combines low-noise performance with low-power requirements.

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Lima, Walber Cunha. "Bio?tica e biodireito: interfaces e conflu?ncias." Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13682.

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Made available in DSpace on 2014-12-17T14:20:10Z (GMT). No. of bitstreams: 1 WalberCL_DISSERT.pdf: 2666620 bytes, checksum: 78f878ac7c15fd16c68f25f754d21e15 (MD5) Previous issue date: 2012-12-17 This thesis addresses the development of technoscience in times of transnational globalization and highlights the vulnerability of the discourse of social progress, which may be replaced by evidence of social risk before the artificiality of nature and humanity. That demands an ethical and legal responses to events that impose the necessity of an ethical control in biotechnology research involving human beings contributing to the rise of Bioethics and Biolaw as fields of knowledge. This theme is studied from a multidisciplinary perspective seeking a dynamic dimension in the interpretation of research data reconnecting Social Sciences to Legal Sciences (Biolaw) and to Philosophy (Bioethics), in order to obtain answers to the problems posed. The objective delimited is to examine the interfaces between Biolaw and Bioethics, in order to observe the confluence of these areas of knowledge. Biolaw is considered as a new legal branch derived from the paradigmatic transition of Law and wonders how it will stand before questions resulting of social transformations caused by biotechnological development that endangers humans and society. It is concluded that the relationship between Bioethics and Biolaw is recursive and inseparable and it contributed to the "unthink" of traditional legal model of linear view/reductionist allowing that the "certainties" will be replaced by "possibilities", which comes to enable Biolaw to confront the issues caused by the development of biotechnology that violates physically and morally the human person. It is perceived, therefore, that Biolaw is driven and aided by bioethical reflections and it positions itself before the dilemmas caused by biotechnology in creating, interpreting and applying coercive rules which aims to protect the human being, his offspring and society Aborda-se o desenvolvimento da tecnoci?ncia em tempos de globaliza??o transnacional e evidencia-se a vulnerabilidade do discurso de progresso social, podendo este ser substitu?do pela evidencia de risco social ante a artificializa??o da natureza e da humanidade, o que demanda respostas ?tico-jur?dicas a partir de acontecimentos que imp?em a necessidade de um controle ?tico nas pesquisas biotecnol?gicas envolvendo seres humanos, fazendo emergir a Bio?tica e o Biodireito enquanto campos do conhecimento. Estuda-se o tema a partir de uma perspectiva transdisciplinar, em busca de uma dimens?o din?mica na interpreta??o dos dados da pesquisa religando as Ci?ncias Sociais ?s Ci?ncias Jur?dicas (Biodireito) e ? Filosofia (Bio?tica), com vistas a obter respostas ? problem?tica formulada. Delimita-se como objetivo examinar as interfaces entre o Biodireito e a Bio?tica, de forma a observar as conflu?ncias dessas ?reas do saber. Considera-se o Biodireito como um novo ramo jur?dico oriundo da transi??o paradigm?tica do Direito e indaga-se como ele se posicionar? frente ?s quest?es decorrentes das transforma??es sociais provocadas pelo desenvolvimento biotecnol?gico que coloca em risco o ser humano e a sociedade. Conclui-se que a rela??o entre o Biodireito e a Bio?tica ? recursiva e indissoci?vel e contribuiu para o despensar do modelo jur?dico tradicional de vis?o linear/reducionista permitindo que as certezas sejam substitu?das pelas possibilidades , o que vem possibilitar ao Biodireito enfrentar as quest?es provocadas pelo desenvolvimento biotecnol?gico que violam f?sica e moralmente a pessoa humana. Observa-se, assim, que o Biodireito ? impulsionado e auxiliado pelas reflex?es bio?ticas e se posiciona frente aos dilemas provocados pela biotecnologia criando, interpretando e aplicando normas coercitivas que visem proteger o ser humano, sua descend?ncia e a sociedade

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SALASSI, SEBASTIAN. "Charge and hydrophobicity effects at nano-bio interfaces." Doctoral thesis, Università degli studi di Genova, 2020. http://hdl.handle.net/11567/999127.

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Gold nanoparticles coated with bio-compatible ligands are promising tools for biomedical applications due their water solubility, bio-compatibility and efficient light-to-heat conversion. In in vivo applications, nanoparticles come in contact with many biological molecules before being delivered to cells. The understanding of the physical and chemical nature of these different nano-bio interfaces is crucial to the rational design of nanoparticles with biomedical applications. The aim of this thesis is to understand, by molecular dynamics, how the composition, hydrophobicity and charge of the ligand shell of a small gold nanoparticle can influence its interaction with i. the solvent, ii. model biological membranes and iii. serum proteins. For each of these relevant interfaces we address a specific case of study. In our first case study, we address the role of ligands during the transfer of heat from a hot irradiated gold nanoparticle to the surrounding solvent (water). Indeed, in photothermal therapies laser-irradiated resonant nanoparticles convert light into heat, which is then released to the surrounding biological tissues. Nevertheless, no clear physical interpretation is currently available to explain thermal transport at the nanoparticle surface, where a solid-liquid (metal--ligand) interface is coupled to a liquid-liquid (ligand--solvent) interface. We use computer simulations to show that thermal transport at the nanoparticle surface depends on solvent diffusivity at the ligand--solvent interface. Furthermore, using physical indicators of water confinement around hydrophobic and hydrophilic ligands, we develop a predictive model to allow engineering of nanoparticle coatings with the desired thermal conductivities at the nanoscale. The second case study is the interaction between an anionic, monolayer-protected gold nanoparticle and a model neutral lipid membrane. The cell membrane is the first barrier that gold nanoparticles meet in cell-targeted applications. Here we show how the nanoparticle surface functionalization, and in particular its charge state, can drive the mechanism of interaction with a zwitterionic lipid membrane. Our third case study is the interaction between a monolayer-protected gold nanoparticle and a serum protein, ubiquitin. Indeed, when nanoparticles circulate in the bloodstream, they come in contact with many serum proteins, which can irreversibly bind to nanoparticles, thus changing the surface they expose to the biological environment. We combine computer simulations and experimental results to study how the ligand charge and composition influence the interaction between nanoparticles and ubiquitin. We find that interfacial water molecules are more bound to the nanoparticles with the largest negative charge and this reflects in an increase of their hydrodynamic radius and in a slower kinetics of binding to the protein during unbiased simulations.

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Lin, Erica (Erica S. C. ). "Bio-inspired design of geometrically-structured suture interfaces and composites." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98580.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2015. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. Cataloged from student-submitted PDF version of thesis. Includes bibliographical references (pages 90-93). Nature is filled with incredible examples of multi-functional materials that have evolved to possess tailored mechanical behavior. This thesis explores the structure-function-property relationship and design principles of geometrically-structured suture interfaces and composites. Suture interfaces are mechanical structures found in rigid natural materials (e.g. human skulls, turtle shells, seashells) that bear loads and provide flexibility for respiration and growth. The geometry of suture interfaces has been shown to vary within species, across species, through development, and over time as organisms evolve. Using mechanical testing of 3D-printed, bio-inspired prototypes, finite element simulations, and analytical modeling, this thesis offers a systematic, comprehensive understanding of the relationship between suture interface geometry and mechanical behavior and provides insight into the suture interface geometries that exist in nature. Triangular, general trapezoidal, and hierarchical suture interfaces and composites are designed, fabricated, and tested. The stiffness, strength, toughness, and failure mechanisms of suture interfaces are shown to be directly influenced by suture geometry. Therefore, mechanical behavior of suture interfaces can be tailored or amplified through small changes in geometry. In addition, the bending behavior of suture composites can also be tailored through changes in suture interface geometry. With a detailed understanding of the deformation mechanisms of suture composites, optimal, multi-scale, hierarchical geometries can be designed. by Erica Lin. Ph. D.

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Cai, Yixiao. "Bio-Nano Interactions : Synthesis, Functionalization and Characterization of Biomaterial Interfaces." Doctoral thesis, Uppsala universitet, Tillämpad materialvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-277121.

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Current strategies for designing biomaterials involve creating materials and interfaces that interact with biomolecules, cells and tissues. This thesis aims to investigate several bioactive surfaces, such as nanocrystalline diamond (NCD), hydroxyapatite (HA) and single crystalline titanium dioxide, in terms of material synthesis, surface functionalization and characterization. Although cochlear implants (CIs) have been proven to be clinically successful, the efficiency of these implants still needs to be improved. A CI typically only has 12-20 electrodes while the ear has approximately 3400 inner hair cells. A type of micro-textured NCD surface that consists of micrometre-sized nail-head-shaped pillars was fabricated. Auditory neurons showed a strong affinity for the surface of the NCD pillars, and the technique could be used for neural guidance and to increase the number of stimulation points, leading to CIs with improved performance. Typical transparent ceramics are fabricated using pressure-assisted sintering techniques. However, the development of a simple energy-efficient production method remains a challenge. A simple approach to fabricating translucent nano-ceramics was developed by controlling the morphology of the starting ceramic particles. Translucent nano-ceramics, including HA and strontium substituted HA, could be produced via a simple filtration process followed by pressure-less sintering. Furthermore, the application of such materials as a window material was investigated. The results show that MC3T3 cells could be observed through the translucent HA ceramic for up to 7 days. The living fluorescent staining confirmed that the MC3T3 cells were visible throughout the culture period. Single crystalline rutile possesses in vitro bioactivity, and the crystalline direction affects HA formation. The HA growth on (001), (100) and (110) faces was investigated in a simulated body fluid in the presence of fibronectin (FN) via two different processes. The HA layers on each face were analysed using different characterization techniques, revealing that the interfacial energies could be altered by the pre-adsorbed FN, which influenced HA formation. In summary, micro textured NCD, and translucent HA and FN functionalized single crystalline rutile, and their interactions with cells and biomimetic HA were studied. The results showed that controlled surface properties are important for enhancing a material’s biological performance.

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Doherty, Eamon Patrick. "An investigation of bio-electric interfaces for computer users with disabilities." Thesis, University of Sunderland, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340946.

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A commercially available brain-body interface, the `Cyberlink' which was developed by a Dr Andrew Junker, has been evaluated as a potential interface device for persons with a severe disability such as traumatic brain injury. The literature concerning brain computer interfaces and other input devices is surveyed and it is shown there is a need to investigate the Cyberlink as an assistive technology device for persons with a disability. The investigation was carried out in four phases, using forty-four persons with and without physical, mental and sensory impairments as participants. The first phase consisted of a survey of common assistive technology devices along with the Cyberlink. This demonstrated that many users were able to operate alternative devices. The second phase identified a group of distinct users that could only use a Cyberlink to both recreate and communicate with the outside world. These participants formed the focus group. A modified contextual inquiry and design was performed at the same time as the phase two studies. The data collected from the contextual inquiry and design drove the design for a communication application, developed in phase three, that gave the focus group the opportunity to select yes and no answers to questions. Phase four was the testing phase of the new yes / no application. This identified some design flaws that were addressed following a target acquisition study which showed that some paths in the design were difficult to steer through. New prototypes were created and tested using this data. The final yes / no program allowed the focus group to select yes and no answers on prompting, albeit with a les's than 100% success rate. Success appeared to depend on the focus group not beirighampered by the inconsistent debilitation of their injuries and medications. The utility of the Cyberlink for the focus group for recreating and performing elementary communication is thus demonstrated for occasions when settings are relevant, medications are not dampening bio-signals, and the inconsistencies of the brain injury allow them to control the cursor.

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He, Jinbo. "Directing synthetic and bio-nanoparticle self-assembly at liquid and polymer interfaces." Amherst, Mass. : University of Massachusetts Amherst, 2009. http://scholarworks.umass.edu/dissertations/AAI3349725/.

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Tristl, Matthias Hermann. "Design of bio-mimetic interfaces based on genetically engineered oligomers of lumazine synthase." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972319255.

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Zhao, Jie. "The application of functionalized nanocarbon materials as bio-interfaces in early diagnosis support." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/13314.

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The aim of this study is to design and develop novel carbon nanotube and graphene based platforms as biosensors for electrochemically detecting dopamine. The use of such novel nanostructure, which was introduced with functional groups or bio-recognizition molecular, will enable the development of affinity-based biosensors for disease diagnostics and therapy monitoring. The electrical devices are extremely useful for dopamine determination in a fast and simple way. In this study, a Nafion/MWCNT chip prepared by inkjet printing was developed for rapid dopamine determination in human serum. A well dispersed Nafion/MWCNT composite was investigated with homogeneous double layers which increased the efficiency of dopamine detection, producing a measurable current change at the underlying sensor electrode. This platform as described successfully demonstrated detection of dopamine concentrations (0.1 M to 10 M, R=0.999) using DPV and amperometry methods. This direct measurement of dopamine in serum samples without pretreatment and dilution is reported for the first time in a Nafion/MWCNT system. In addition, to improve the specificity of the detecting probe, the direct electrochemical detection of antibody-antigen recognition was developed. Graphene can be used as an electrode surface for sensitive detection of a label. Graphene sheets were modified with gold nanoparticles or the dopamine antibody fragments (Fab’) loaded with sulphur binding with gold. Unfortunately, such bio-sensing systems did not perform sensitively and selectively for detection of the neurotransmitters/neurochemicals by utilizing certain nanostructure and introducing various functional groups. Further study will be conducted on analysing fragments’ and the whole antibodies’ activity and affinity of specific recognition.

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Dhruv, Harshil D. "Controlling Nonspecific Adsorption of Proteins at Bio-Interfaces for Biosensor and Biomedical Applications." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/276.

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Partitioning of poly(ethyleneglycol) (PEG) molecules in 2-D and 3-D systems is presented as a self-assembly approach for controlling non-specific adsorption of proteins at interfaces. Lateral restructuring of multi-component Langmuir monolayers to accommodate adsorbing proteins was investigated as a model 2-D system. Ferritin adsorption to monolayers containing cationic, nonionic, and PEG bearing phospholipids induced protein sized binding pockets surrounded by PEG rich regions. The number, size, and distribution of protein imprint sites were controlled by the molar ratios, miscibility, and lateral mobility of the lipids. The influence of PEG chain length on the ternary monolayer restructuring and protein distribution was also investigated using DSPE-PEGx (x= 7, 16, 22). Monolayer miscibility analysis demonstrated that longer PEG chains diminished the condensed phase formation for a fixed ratio of lipids. Thus, incorporation of longer PEG chains, intended to diminish protein adsorption outside of the imprint sites of cationic / non-ionic lipids, leads to dramatic changes in monolayer phase behavior and protein distribution in this 2-D system. The assembly of PEG-amphiphiles at elastomer surfaces and subsequent protein adsorption was investigated as a model 3-D system. Polydimethylsiloxane (PDMS) substrates were modified with block copolymers comprised of PEG and PDMS segments by two methods: (1) the block copolymer was mixed with PDMS during polymerization; (2) the block copolymer diffused into solvent swollen PDMS monoliths. Hydrophilic surfaces resulted for both approaches that, for 600 D block copolymer, exhibited up to 85% reduction in fibrinogen adsorption as compared to native PDMS. Higher MW block copolymers (up to 3000 D) resulted in less hydrophilic surfaces and greater protein adsorption, presumably due to diffusion limitations of copolymer in the PDMS monolith. All modified PDMS surfaces were dynamic and restructured when cycled between air and water. PDMS transparency also decreased with increase in block copolymer concentration for both methods, limiting this modification protocol for applications requiring high polymer transparency. The 2-D system presents a bottom-up approach, where adsorbing protein constructs the binding site, while the 3-D system presents a top down approach, where protein-binding elements may be introduced into the PEG-bearing polymer for fabrication of surfaces with controlled protein adsorption.

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Wiederkehr, Nadir Ana. "Etat monomère et agrégé de molécules à activité bio-redox en solutions et aux interfaces /." [S.l.] : [s.n.], 1990. http://library.epfl.ch/theses/?nr=872.

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Miriani, M. "PROTEIN UNFOLDING ON INTERFACES: A STRUCTURAL AND FUNCTIONAL STUDY." Doctoral thesis, Università degli Studi di Milano, 2012. http://hdl.handle.net/2434/170496.

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The spontaneous adsorption of protein molecules on interfaces is an ubiquitous phenomenon in natural and man-made systems. The structural rearrangement caused by the direct contact with the sorbent phase may affect protein biological activity, including bioavailability, and ability to bind micro- and macromolecular ligands. Moreover, protein immunoreactivity has been assessed to change if protein molecules interact with an hydrophobic phase; indeed adjuvant are hydrophobic substances that act as enhancers in antibodies production. Whether proteins unfold randomly or through subsequent ordered and eventually reversible steps remains often unknown, and information about the molecular determinants of the “gain of function” or the “loss of function” observed upon adsorption is scarce. The aim of this work is to understand the structural and functional changes that soy storage proteins (beta-conglycinin and glycinin) and bovine betalactoglobulin (BLG) undergo after adsorption on hydrophobic nanostructured surfaces. Protein conformational changes after adsorption on interfaces were evaluated by using different techniques, including fluorescence and solid-state fluorescence spectroscopy, CD spectroscopy, along with limited proteolysis followed by recognition of released peptides by MS. Moreover, changes in biological behavior were evaluated by measuring changes in immunoreacivity that may be relevant from the standpoint of immune response or immunomodulation. Experiment aimed to evaluate the influences of interface denaturated protein on live cells were carried out. For this purpose BLG and BLG-stabilized emulsions, both labeled with FITC, were incubated with monocyte and differences in protein uptake were evaluated by citofluorimetry. In order to have a model of BLG denaturation on the polystyrene interface, an in silico study was performed. The simulation was carried out using the computational suite MOE (Molecular Operating System). In this work structural changes of -conglycinin and glycinin in solution were compared to those occurring when the proteins are adsorbed at the oil-water interface. Both proteins undergo structural modifications after adsorption on the oil droplet surface. From the standpoint of protein chemistry, the modifications occurring at the interface with the proteins investigated here have some peculiar traits, in what both these proteins expose their tryptophan-containing extension regions to the aqueous phase rather than to the droplet interior, as observed for other proteins. It is very important to note that, in beta-conglycinin, tryptophans are present in the extension domains of alpha and alpha’ subunits, and the present fluorescence data confirm previous results demonstrating that the polar extension regions in these proteins are important for their emulsifying ability. These results support the hypothesis that while the a and a’ core domains interact with oil phase, the extension regions protrude into the aqueous phase and stabilize the emulsion droplets by providing the necessary polar regions. Also glycinin’s tryptophans containing regions are exposed to the aqueous phase. However, the multiplicity of glycinin’s genetic variants makes it much more challenging to derive definite answers from the hydrophobicity profiles of this protein, and some more detailed proteomic work is needed to better understand which portion of the protein anchors to the interface. It is also interesting to note that heat treatment does not affect the structural features of either protein once they are adsorbed at the oil-water interface. In other words, the modifications occurring upon adsorption at the interface appear to “lock” the protein structure in a conformation that is insensitive to further physical denaturation, at least under the temperature/time regimes employed in this work. As a matter of fact, it is somewhat expected that, in emulsions, the structural regions more sensitive to the entropic changes ensuing from alteration in the water structure (i.e., the protein hydrophobic core) are at least partially buried into the non-polar lipid phase, and thus are insensitive to temperature-dependent changes in the colligative properties of the solvent. The various peculiarities of these systems and their practical relevance seem worth further investigation. We are currently addressing the molecular details of the observed events, in an attempt to identify specific molecular determinants of the different behaviour of these proteins, as well as the changes occurring during heating, and to assess whether the conformational changes reported here result in biologically relevant modifications when emulsions are consumed as food. Also BLG structure changes after interaction with an hydrophobic interface. The intrinsic fluorescence spectrum of adsorbed BLG is red-shifted compared with the free-protein one thus indicating that the adsorbed protein assumes a new structure in which Trp19, usually buried inside the hydrophobic core, is exposed to water. Moreover, adsorbed BLG increases ≈2 folds its global quantum yield. The only free thiol in BLG is on Cys121, which is buried in the native structure, but becomes readily and almost completely accessible after adsorption. The overall BLG surface hydrophobicity seems to increase after interaction with the hydrophobic surface, confirming the occurrence of major rearrangements. BLG sensitivity towards trypsin – and therefore the resulting peptidic pattern - is modified as a function of the hydrophobic support where the protein is adsorbed. In fact, in the case of NP-adsorbed BLG trypsin resistance is similar to the one of free BLG, whereas it dramatically decreases for emulsion-BLG. All these data demonstrate an extended stretch of the native structure after adsorption on hydrophobic surfaces with the exposure of new protein regions usually buried from the aqueous media. Changes in immunoreactivity occurred after adsorption on hydrophobic surfaces. BLG adsorbed on oil droplet surface is more reactive (≈35%) than the free protein by using the 5G6 MAB, and also it is more reactive (≈110%) when using the 1E3 MAB. BLG adsorbed on latex NP is likely to increase its immunoreactivity by using both MAB, that indicates that BLG assumes different structures as a function of the interacting interface(s). Cells experiments show how the BLG internalization by monocites follows two different kinetics according to protein physical state. Moreover the absorption of adsorbed BLG seems to be not influenced by competition of free BLG, leading us to hypothesize the presence of two different pathway for the protein internalization depending on their physicals state. The in silico denaturation simulations demonstrate that the interaction orientation is fundamental for the type and magnitude of protein structure reorganization. The system, all build by us, seems to be very stable, and the latex denaturating interface should be used with others proteins. In conclusion in this thesis I described in deeply the structural modification that three protein, whit a huge importance for nutrition and food science, undergo after adsorption on different model hydrophobic interfaces. I also produced an in silico model for computational prediction of protein denaturation on polystyrene interface. Physiological implication regarding protein structural reorganization were also explored.

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Storelli, Daniele <1990&gt. "TWO-DIMENSIONAL BIO-ACTIVE NANOSTRUCTURED INTERFACES AIMED AT ACCURATE MONITORING OF CLINICALLY RELEVANT CANCER BIOMARKER PROTEINS." Master's Degree Thesis, Università Ca' Foscari Venezia, 2020. http://hdl.handle.net/10579/17131.

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Circulating HER2 extracellular domain (HER2 ECD) levels were proposed as a surrogate for HER2 tissue expression to monitor breast cancer patients. Currently, analytical tools capable of detecting HER2 ECD level rely on commercially available ELISA (or ELISA-derived) assays employing antibodies recognizing undisclosed or unknown epitopes, providing sensitivity that very often is not adequate to detect the very low level the of cancer biomarker protein (< 12 ng/ml) in real samples. This is particularly true during the treatment follow-up to identify acquired resistance to HER2-targeted antibody therapy. Moreover, the analyses can be run only in centralized laboratories by qualified personnel, thus increasing cost and time. Therefore, there is an urgent need to develop new user-friendly analytical tools enabling a rapid, reliable analysis of real sample, thus reducing the costs and time required for the analyses. However, the sensitivity of SPR is limited by the nature of the receptors tethered on its biosensing platform. Heavy-weight antibodies (150 kDa) provide a dramatic change in the refractive index and dielectric constant at the gold layer/sample interface, so that a high number of antigens are required to be captured in order to provide a significant response. Nanobodies have been recently proved to be a valid alternative to antibodies, as the feature a lower molecular weight and a simpler molecular structure that can in principle allow devising a nanostructured biosensing platform of properly oriented receptors. In fact, a further functionalization of the nanometric layer of gold employed in the SPR with nanostructured and optically transparent materials, such as graphene, may be advantageous both in terms of further functionalization, exploiting the carbon chemistry, and electronic properties, enhancing the sensitivity. Two dimensional materials have emerged as ideal candidates for the realization of miniaturized biosensor platforms. However, a comprehensive understanding of the bioanalytical mechanisms at such atomically thin 2D material is central to such developments. In this work a graphene-based bio-nanointerface has been realized by transferring chemical vapor deposited (CVD) graphene on top of a gold SPR-active substrate. The graphene layers have been transferred in different stacked patterns and the interfacial inhomogeneities and topological variations, induced by the transfer process have been investigated by using imaging Ellipsometry, Atomic Force Microscopy and Surface Plasmon Imaging techniques. A bioanalytical framework has been created to quantify the influence of the 2D layer inhomogeneities on the bio interactions and to tune the accuracy of the biosensing. A microfluidic system together with the Kinetic-SPR have been deployed to investigate the biomolecular interactions between the HER2-ECD and three newly developed nanobodies.

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Li, Qifei. "In Vitro, Non-Invasive Imaging and Detection of Single Living Mammalian Cells Interacting with Bio-Nano-Interfaces." DigitalCommons@USU, 2015. https://digitalcommons.usu.edu/etd/4520.

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Understanding of bio-nano-interfaces of living mammalian cells will benefit the identification of cellular alterations (e.g. nucleic acids, amino acids, biomechanics, etc.) due to external stimuli, the design of biomaterials (e.g. nanoparticles, nanotubes) and the investigation of the interaction between cells and bio-nano-interfaces (e.g. cell differentiation on 3D nanostructured materials). Analytical techniques can be applied to evaluate the chemical, physical, and mechanical properties of mammalian cells when exposed to such bio-nano-interfaces. In this study, non-invasive advanced spectroscopy techniques including atomic force microscopy (AFM) and Raman microscopy (RM), in conjunction with traditional biological methods are utilized to elucidate specific characteristic information for biological samples and how these property changes reflect the interaction with external stimuli. The focus of this dissertation is on the biophysical, biochemical and cytotoxic detection of mammalian cells interacting with bio-nano-interfaces, and this dissertation can be classified into three topics: biomechanics/cellular biopolymers measurement, bio-interfaces and nano-interfaces studies. For the topic of biomechanics/cellular biopolymers measurement, cellular biophysical and biomechanical properties could be used as differentiation markers to classify cellular differentiation. For the bio-interfaces part, it was observed that BRMS1 expression changed cellular biochemical and biomechanical properties, and the expressions of reactive oxidative species (ROS), apoptosis and cell viability of five types of cells displayed similar patterns over doxorubicin (DOX) incubation time. Secondly, A549 cells were treated with diesel exhaust particles (DEP) and resveratrol (RES) to study the effect of RES on the DEP-induced cells, and it was found that RES can alleviate DEP intervention on cellular structure and increase DEP-induced biomechanical and inflammatory changes. For the nano-interfaces topic, first we synthesized a hybrid nanoparticle with the multimodal properties of fluorescence imaging, Surface-enhanced Raman spectroscopy (SERS) detection and photothermal therapy (PTT) for single living cell analysis of epidermal growth factor receptor (EGFR) and specifically killed cancer cells with high EGFR expression. Additionally, to increase surface area, light-heat conversion efficiency and biocompatibility, we developed a silica coated nanoparticle conjugated with anti-human epidermal growth factor receptor 2 (HER2) antibody. Finally, three-dimensional TiO2 nanotubes with Au nanoparticles coating were synthesized and used to study trophoblast-derived stem-like cells growth on such 3D nanostructures.

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Gautier, Clémentine. "Approches biologiques et physico-chimiques des interactions silice/organismes vivants." Paris 6, 2007. http://www.theses.fr/2007PA066028.

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Pour l’étude de l’interaction entre la silice et les organismes vivants, nous nous sommes intéressés aux diatomées, algues unicellulaires, fascinantes de part la complexité de leur coquille de silice. D’abord nous avons étudié les propriétés mécaniques et la porosité des gels de silice. Puis, nous avons montré qu’une fois encapsulées dans les gels de silice, les diatomées conservent une activité photosynthétique sur une plus longue période que lorsqu’elles sont en milieu de culture et qu’elles possèdent la capacité de dissoudre la silice autour d’elles. Enfin, comme les diatomées contrôlent la silice au sein d’un espace confiné, nous avons étudié l’effet du confinement sur la formation de la silice en présence de molécules biomimétiques. L’ensemble de ces travaux contribuent à une meilleure compréhension de l’interface entre les diatomées et la silice sous différentes formes et démontrent l’intérêt de la chimie sol-gel de la silice dans un cadre biologique.

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Gonzalez, Losada Pedro. "Development and Characterization of a new generation of retinal implants." Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1119.

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D’après les données de l’agence International de Prévention de la Cécité, 253 millions de personnes souffrent de pathologies visuelles dans le monde. Il existe des pathologies affectant les photorécepteurs de la rétine causant des millions de déficients visuels sans traitement efficace disponible. Les implants rétiniens ont déjà montré sa capacité pour stimuler de façon électrique les cellules rémanentes de la rétine grâce à un réseau de micro-électrodes de façon à obtenir une réponse neuronale puis une perception visuelle. Ces travaux de thèse en lien avec les implants rétiniens porteront sur deux aspects principaux concernant de nouvelles configurations de micro-électrodes et une analyse comparative des matériaux constitutifs des électrodes avec des tests en vieillissement long terme. Pour le premier aspect, de nouvelles géométries d’électrodes ont été développées en différentes phases : en commencent par une modélisation par éléments finis de la micro-électrode, suivi par la micro fabrication des prototypes et les expériences in-vivo. Pour l’étude du vieillissement des matériaux constitutifs des micro-électrodes, un banc de caractérisation a été développé pour reproduire les conditions de pH, T et stimulation électrique d’un implant réel. Le banc nous permet aussi d’étudier l’évolution de façon comparative des caractéristiques des différents matériaux grâce à la mesure de son impédance électrochimique Regarding to data provided by the International Agency for Prevention of Blindness, 253 million people suffer some kind of visual impairment around the world. There is a group of diseases that affect the photoreceptors causing millions of impairment cases around the world that do not have an efficacious treatment. Retinal prostheses have proved to electrically stimulate the remaining cells of the retina by means of implantable microelectrode arrays to elicit their response and therefore visual perception. This PhD work tries to study two aspects of these devices: first, new electrode geometries that stimulate the cells in a more efficient manner; and second, the ageing of the different material used for the fabrication of the microelectrodes. For the first aspect new electrode geometries have been developed based on the state of the art. This development has been divided in different phases beginning with a FEM modeling of the electrode, followed by the microfabrication of the structures and their test in-vivo. In order to study the ageing of the microelectrode materials, a characterization bench that reproduces the conditions that an implant has to face during its implantation has been developed. This bench allows us to study in a comparative manner the evolution of the characteristics of the different materials thanks to the measurement of their electrochemical impedance

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Feng, Chuan Liang. "Fabrication of robust (bio)interfaces based on reactive polymer films surface confinement, reactivity and pattern fabrication on multiple length scales /." Enschede : University of Twente [Host], 2005. http://doc.utwente.nl/50893.

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McEwen, Gerald Dustin. "Raman Microspectroscopy, Atomic Force Microscopy, and Electric Cell-Substrate Impedance Sensing For Characterization of Bio-Interfaces: Molecular, Bacteria, and Mammalian Cells." DigitalCommons@USU, 2012. https://digitalcommons.usu.edu/etd/1251.

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A fundamental understanding of bio-interfaces will facilitate improvement in the design and application of biomaterials that can beneficially interact with biological objects such as nucleic acids, molecules, bacteria, and mammalian cells. Currently, there exist analytical instruments to investigate material properties and report information on electrical, chemical, physical, and mechanical natures of biomaterials and biological samples. The overall goal of this research was to utilize advanced spectroscopy techniques coupled with data mining to elucidate specific characteristic properties for biological objects and how these properties imply interaction with environmental biomaterials. My studies of interfacial electron transfer (ET) of DNA-modified gold electrodes aided in understanding that DNA surface density is related to the step-wise order of which a self-assembled monolayer is created on a gold substrate. Further surface modification plays a role in surface conductivity, and I found that electro-oxidation of the DNA involved the oxidation of guanine and adenine nucleotides. Scanning tunneling microscopy (STM) was used to create topography and current images of the SAM surfaces. I also used Raman microspectroscopy (RM) to obtain spectra and spectral maps of DNA-modified gold surfaces. For studies of bacteria, atomic force microscopy (AFM) and scanning electron microscopy (SEM) images showed similar morphological features of Gram-positive and Gram-negative bacteria. Direct classical least squares (DCLS) analysis aided to distinguish co-cultured strains. Fourier transform infrared (FTIR) spectroscopy proved insightful for characteristic bands for Gram-positive bacteria and a combined AFM/RM image revealed a relationship between culture height/density and peak Raman intensity. In our mammalian cell studies we focused on human lung adenocarcinoma epithelial cells (A549), metastatic human breast carcinoma cells MDA-MB-435 (435), and non-metastatic MDA-MB-435/BRMS1 (435/BRMS1). RM revealed similarities between metastatic 435 and non-metastatic 435/BRMS1 cells compared to epithelial A549 cells. AFM showed increases in biomechanical properties for 435/BRMS1 in the areas of cell adhesion, cell spring constant, and Young’s modulus. Fluorescent staining illustrates F-actin rearrangement for 435 and 435/BRMS1. Electric cell-substrate impedance sensing (ECIS) revealed that 435 cells adhere tightly to substrata and migrate rapidly compared with 435/BRMS1. For ECIS, ≤10-fold diesel exhaust particles (DEP) concentration exposure caused clastogenic DNA degradation whereas ≥25-fold DEP exposure caused cytotoxic results. Resveratrol (RES) at 10 μM showed minimal to mild protection against DEP before and after exposure and aided in improving injury recovery.

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Han, Bo [Verfasser]. "Interfacial electrochemistry and in situ SEIRAS investigations of self-assembled organic monolayers on Au-electrolyte interfaces / Forschungszentrum Jülich in der Helmholtz-Gemeinschaft, Institute of Bio- and Nanosystems. Bo Han." Jülich : Forschungszentrum, Zentralbibliothek, 2006. http://d-nb.info/987947249/34.

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Szczepanowska, Hanna M. "Living systems on heterogeneous cellular substrate : contribution to a better understanding of dynamic interfaces of fungal pigmentation and paper in biodeterioration of cultural heritage." Thesis, Ecully, Ecole centrale de Lyon, 2012. http://www.theses.fr/2012ECDL0031/document.

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La bio-détérioration des documents culturels compte parmi les types de détériorations les plus complexes que sont amenés à subir ces objets; et ce, parce qu’elle implique des organismes vivants ainsi que la conjonction de nombreux facteurs. Il existe différentes formes de biodétérioration; les taches de substrat (support?) engendrées par des champignons pigmentés en sont un exemple. Une multitude d’actions se développent aux “interfaces” entre le substrat (support?) et les champignons, depuis le premier contact avec les spores, en passant par la prolifération fongique, jusqu’aux interactions avec l’environnement. L’analyse multi-échelle et multisensorielle de l’interface entre les moisissures pigmentées noires et le support papier est le sujet de ces thèses. Deux types de pigmentations fongiques noires ont fait l’objet d’une analyse; la première apparaissait spontanément sur les œuvres d’art , la deuxième résultait d’une pigmentation déclenchée en biosimulation, sur des papiers connus, dans un environnement maitrisé. Les caractéristiques des papiers telles que le relief et la structure de la surface, la morphologie des champignons, les processus de dépôt de la biomasse pigmentée, ainsi que la prolifération fongique, ont fait l’objet de multiples examens, tant en termes d’instruments que de méthodes :microscopie à lumière transmise, microscopie électronique à balayage (MEB) dans une chambre à pression variable, microscopie confocale à balayage laser, profilomètre confocal à lumière blanche, microtomographie aux rayons L’objectif ultime étant de développer une stratégie de préservation des objets du patrimoine culturel bio-détériorés, le choix des instruments et des méthodes d’analyse était dicté par un souci pratique qui limitait l’échantilllonage des éléments analysés. Ce travail constitue une première tentative afin de mieux comprendre les forces en présence au niveau des “interfaces”, dans le cas des taches sur le papier dues aux champignons Biodeterioration of cultural materials is one of the most complex types of deteriorations that cultural materials are subjected to mainly, because it involves living organisms and synergy of many factors. There are different forms of biodeterioration, stains of substrate caused by pigmented fungi is one of them. Multitude of events occurs at interfaces between substrate and fungi, from the moment of spores’ first contact with surfaces, next fugal growth and their responses to the environment. Multiscale and multisensory analysis of interfaces between black pigmented fungi and paper substrate was the subject of these theses. Two types of black fungal pigmentations were analyzed; one that occurred on the original artworks the other one was induced in biosymulation on known papers in controlled environment. Paper characteristics, such as surface topography and structure, morphology of fungi and patterns of their pigmented bio-mass deposition as well as fungal growth were examined with an array of analytical instruments and methods: transmitted light microscopy, scanning electron microscopy in variable pressure, confocal laser scanning microscopy, white light confocal profilometer and X-ray microtomography. The ultimate goal was to develop a preservation strategy for biodeteriorated cultural heritage material; therefore the choice of the analytical methods and instruments was dictated by real-life protocols that limit sampling of cultural materials. This works is the first attempt towards a better understanding of interfacial forces in fungal stains on paper

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22

Ponzio, Florian. "Synthesis at different interfaces of bio-inspired films from mussels' byssus : influence of the oxidant nature at the solid/liquid interface and the addition of polymer at the air/water interface." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAE041/document.

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Les matériaux à base de polydopamine (PDA) s’inspirent de la forte adhésion du byssus de la moule sous l’eau. L’oligomérisation de la dopamine dans un milieu basique permet la formation de revêtement de PDA sur n’importe quel matériau. En plus de la simplicité du procédé celui-ci est vert et versatile. La PDA a des propriétés similaires aux mélanines, d’où son utilisation dans le domaine des phénomènes de conversion d’énergie, de l’environnement et du biomédical. Cependant la structure de la PDA étant inconnue, l’élaboration de matériaux basés sur la relation structure propriétés est difficile. L’un des buts de cette thèse a été de comprendre cette relation pour élaborer de nouveaux matériaux de PDA. En choisissant l’oxydant adéquat nous avons déposé un film épais, superhydrophile et biocompatible sur n’importe quels substrats. De plus nous avons découverts la possibilité de former des films de PDA à l’interface air/eau. L’étude de ce phénomène a permis de former des membranes autosupportées et stimuli responsives Polydopamine (PDA) materials are inspired from mussels’ byssus strong adhesion underwater. The oligomerization of dopamine in a basic medium allows forming a PDA coating on virtually any materials. In addition to the simplicity, ecofriendly and versatility of the deposition method, PDA has properties similar to those of melanin pigments and displays many outstanding properties. Thus PDAis widely used in energy, environmental and biomedical sciences. However design of PDA based new materials with tailored properties is a challenge since its structure is still unknown. In that sense one of the aims of this thesis is to gain knowledge in PDA structure-property relationship in order to design PDA materials with new properties. By choosing the appropriate oxidant we deposited thick and superhydrophylic films on any materials for the elaboration of low fouling and biocompatible surfaces. Additionally we discovered the possibility to form PDA films at the air/water interface. The investigation of this phenomenon led to the formation of stimuli responsive free standing membranes

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23

Benavides, Parra Juan Carlos. "Brownian motion of colloidal particles located near different types of interfaces." Thesis, Le Mans, 2017. http://www.theses.fr/2017LEMA1011.

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Le mouvement Brownien dans l’eau de colloïdes proches d’interfaces de différente nature (eau/air, eau/verre, …) est étudié en utilisant une technique de microscopie numérique permettant de reconstruire les trajectoires individuelles en trois dimensions. Des accords satisfaisants entre les trajectoires et les modèles théoriques publiés ont été trouvés pour les cas les plus simples. En outre, nous proposons une approche théorique capable de passer de la configuration d'interface libre (type eau-air) à l'état lié (type liquide-solide). Nous avons également considéré dans ce cadre la situation dans laquelle une interface solide a été fonctionnalisée et rendue hydrophobe pour comparer le mouvement Brownien près de l’interface avec la même interface solide rendue très hydrophile par un traitement au plasma UV-ozone qui crée des groupes hydroxyle (Si-OH ). Nous avons également étudié l'interaction colloïdale et hydrodynamique avec des interfaces recouvertes d’une membrane biomimétique phospholipidique molle (DOPC en phase fluide) ou gelée (DMPC en phase gel), toutes deux recouvrant le verre (SiO2) We explore the Brownian motion of colloids near different interfaces (water-air, water solid,…) using three dimensional digital video microscopy and reconstruction of singles colloids trajectories in 3D over time. Satisfying agreements between data and published theoretical models were found for simplest cases. In addition we propose a theoretical approach able to transit from the free interface configuration (water-air) to the bound condition (liquid-solid). We also considered within this frame the situation where a solid interface was functionalized with a grafted short alkyl chain (flat and hydrophobic fixed wall) to compare with same solid interface made hydrophilic from a UV-ozone plasma treatment that creates hydroxyl groups (Si-OH). From the stabilization of a phospholipid bilayer, we also studied colloidal and hydrodynamic interaction with a soft (DOPC in Lα) or freezed (DMPC at Lβ) biomimetic membrane covering the solid interface (SiO2 glass)

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Xie, Mouzhe. "Probing and Modeling Biomolecule-Nanoparticle Interactions by Solution Nuclear Magnetic Resonance Spectroscopy." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1532049249287026.

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Schoonjans, Nathan. "Établissement d'une boucle de communication bidirectionnelle entre des neurones vivants et des neurones artificiels analogiques pour la conception de neurobiohybrides de nouvelle génération." Electronic Thesis or Diss., Université de Lille (2022-....), 2023. https://pepite-depot.univ-lille.fr/ToutIDP/EDENGSYS/2023/2023ULILN056.pdf.

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Les neurobiohybrides sont des systèmes composés d'un élément artificiel, d'une composante vivante et de l'interface qui les relie. Ces puissants outils permettent de connecter de manière fonctionnelle des éléments électroniques et des structures neuronales in vitro comme in vivo. De nombreux systèmes neurobiohybrides, plus communément appelés neuroprothèses, sont utilisés en médecine pour améliorer la qualité de vie de patients atteints de handicaps (surdité, déficits visuels, paralysie) en leur permettant de recouvrer partiellement les fonctions physiologiques perdues. Les neuroprothèses actuelles sont unidirectionnelles (elles stimulent OU enregistrent l'activité des neurones ciblés) et sont particulièrement énergivores. Intégrer une boucle de rétroaction de sorte que ces systèmes communiquent en temps réel de manière bidirectionnelle avec le tissu nerveux améliorerait leur efficacité tout en élargissant leur potentiel thérapeutique à d'autres conditions pathologiques. La principale difficulté à lever pour permettre l'établissement d'une telle boucle consiste à trouver un système de traitement de signal autonome et suffisamment miniaturisé. En 2017, le groupe Circuits Systèmes Applications des Micro-ondes (CSAM) de l'Institut d'Electronique, de Microélectronique et de Nanotechnologies (IEMN) de Lille a publié un neurone artificiel ultra-efficace en termes de consommation énergétique qui pourrait répondre à ces besoins. Ce neurone émet des potentiels d'action biomimétiques en termes de forme, d'amplitude et de fréquence des signaux émis, et fonctionne de manière entièrement analogique. Dans un précédent doctorat, il a été démontré que ces potentiels d'action biomimétiques permettent bien de stimuler l'activité électrique de neurones vivants. Les travaux présentés ici font suite à cette démonstration et visent à établir une boucle de communication bidirectionnelle complète entre des neurones vivants et ces neurones artificiels. Dans cet objectif, trois axes principaux de travail ont été définis : 1- Optimiser le design et la technologie d'une interface neurobiohybride ; 2- Sélectionner et caractériser de manière morphologique et fonctionnelle des modèles cellulaires vivants maintenus in vitro ; 3- Etablir une première boucle de communication bidirectionnelle entre ces neurones vivants et les neurones artificiels par le biais de l'interface neurobiohybride. Ce manuscrit présente les étapes de fabrication et d'optimisation de l'interface dont la surface a été travaillée pour optimiser les conditions d'enregistrement en milieu électrolytique, notamment par l'ajout d'une couche de passivation isolant les lignes d'accès et un développement de méthodes afin d'optimiser le positionnement des cellules sur les électrodes. Les cellules électriquement actives choisies pour cette démonstration (cellules endocrines hypophysaires murines GH4C1 (lignée établie) et neurones glutamatergiques humains dérivés de cellules souches pluripotentes induites) ont été caractérisées par patch-clamp, imagerie par fluorescence et imagerie calcique. Les premiers enregistrements de l'activité électrique de cellules GH4C1 cultivées dans une interface neurobiohybride ont été réalisés sur un banc d'enregistrement électronique conçu et optimisé au sein du laboratoire pour une détection de signaux de très faible amplitude. Ces travaux sont accompagnés par le développement d'un modèle électrique implémenté sous le logiciel LTSPICE intégrant le signal électrique émis par des cellules GH4C1 et enregistré via l'interface neurobiohybride. Ce faisant, il est possible d'établir une boucle de communication bidirectionnelle entre des neurones vivants et artificiels. En conclusion, ce travail permet d'ouvrir la voie vers une nouvelle génération de neuroprothèses bidirectionnelles Neurobiohybrids are systems composed of an artificial element, a living component and their interface. These powerful tools enable the functional connection of electronic elements and neuronal structures both in vitro and in vivo. Many neurobiohybrid systems, more commonly known as neuroprostheses, are used in medicine to improve the quality of life of patients with disabilities (deafness, visual impairment, paralysis) by enabling them to recover, at least partly, lost physiological functions. Current neuroprostheses are unidirectional (they stimulate OR record the activity of targeted neurons) and are particularly energy-intensive. Integrating a feedback loop into these systems so that they could communicate bidirectionally in real time with nerve tissues would improve their efficiency and effectiveness, while broadening the range of their therapeutic potential. The main difficulty to overcome for enabling such a loop is to find an autonomous and sufficiently miniaturized signal processing system. In 2017, the Circuits Systèmes Applications des Micro-ondes (CSAM) group at Lille's Institute of Electronics, Microelectronics and Nanotechnologies (IEMN) published an ultra-efficient artificial neuron in terms of energy consumption that could meet these needs. This neuron generates biomimetic action potentials of similar shape, amplitude and frequency compared to living neurons, and is entirely analog. In a previous PhD work, it was shown that such biomimetic action potentials can trigger electric activity in living neurons. Following this demonstration, the present work aims to establish the proof-of-concept of the complete bidirectional communication loop between living neurons and these artificial neurons. To reach this goal, three main objectives were set: 1- Optimize the design and technology of a neurobiohybrid interface; 2- Select living cells for in vitro use and characterize them both morphologically and functionally; 3- Establish a first bidirectional communication loop between these living neurons and artificial neurons through the neurobiohybrid interface. This manuscript presents the manufacturing and optimization steps of the interface, whose surface has been enhanced to optimize recording conditions in an electrolytic environment, notably by adding a passivation layer to isolate the access lines and by developing methods to optimize cell position on the electrodes. The electrically active cells chosen for this demonstration (murine pituitary endocrine GH4C1 cells, an established cell line, and human glutamatergic neurons derived from induced pluripotent stem cells) were characterized by patch-clamp, fluorescence imaging and calcium imaging. The first recordings of the electrical activity of GH4C1 cells grown in a neurobiohybrid interface were carried out on an electronic recording bench designed and optimized in-house for detecting very low amplitude signals. This work also led to the development of an electrical model implemented in LTSPICE software, integrating electrical signals emitted by GH4C1 cells as recorded through the neurobiohybrid interface. This enabled the establishment of a bidirectional communication loop between living and artificial neurons. To conclude, this work opens the way to a new generation of bidirectional neuroprostheses

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Martinez, Xavier. "Tracking sans marqueur de modèles physiques modulaires et articulés : vers une interface tangible pour la manipulation de simulations moléculaires." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS231/document.

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Les modèles physiques moléculaires sont depuis longtemps utilisés dans le domaine de la biologie structurale et de la chimie. Malgré l’apparition de représentations numériques qui offrent une grande variété de visualisations moléculaires dynamiques et permettent notamment d’analyser visuellement les résultats de simulations, les modèles physiques moléculaires sont encore fréquemment utilisés. En effet, la manipulation directe et la construction manuelle de modèles physiques moléculaires facilitent l’élaboration et la mémorisation d’une représentation mentale des structures moléculaires 3D. Les techniques d’interaction avec des objets 3D n’atteignent pas encore la finesse et la richesse de perception et de manipulation des modèles physiques. Par ailleurs, l’interaction avec des représentations moléculaires virtuelles est rendue particulièrement difficile car les structures moléculaires sont très complexes du fait de leur taille, de leur caractère tridimensionnel et de leur flexibilité, auquel s'ajoutent la quantité et la variété des informations qui les caractérisent. Pour aborder la problématique de l'interaction avec ces structures moléculaires, nous proposons dans cette thèse de concevoir une interface tangible moléculaire combinant les avantages des représentations physiques et virtuelles. Pour réaliser une interface tangible flexible et modulaire, à l’image des biomolécules à manipuler, ce travail de thèse a dû relever plusieurs défis scientifiques avec pour contrainte majeure le fait de proposer une approche se passant de marqueurs et dispositif de capture 3D complexe. La première étape fut de choisir, concevoir et fabriquer un modèle physique permettant la manipulation de molécules avec de nombreux degrés de libertés. La seconde étape consistait à créer un modèle numérique permettant de reproduire le comportement mécanique du modèle physique. Enfin, il a fallu concevoir des méthodes de recalage utilisant des techniques de traitement d'image en temps réel pour que le modèle physique puisse contrôler, par couplage, son avatar virtuel. En terme de traitement d’image, de nouvelles méthodes ont été conçues implémentées et évaluées afin d'une part, d’identifier et de suivre les atomes dans l’espace image et d'autre part, d'alimenter la méthode de reconstruction 3D avec un faible nombre de points. L'une de nos contributions a été d'adapter la méthode de Structure from Motion en incluant des connaissances biochimiques pour guider la reconstruction. Par ailleurs, la visualisation conjointe de modèles physiques de molécules et de leur avatar virtuel dynamique, parfois co-localisé dans un contexte de réalité augmentée, a été abordée. Pour cela, des méthodes de visualisation haute performance adaptées à ce contexte ont été conçues afin d’améliorer la perception des formes et cavités, caractéristiques importantes des molécules biologiques. Par exemple, l’occultation ambiante ou le raycasting de sphères avec des ombres portées dynamiques permettent d’augmenter un modèle physique en tenant compte de l’illumination réelle pour une meilleure intégration en réalité augmentée. Les retombées de ce travail en terme d’usage sont nombreuses dans le domaine de la recherche et de la pédagogie en biologie moléculaire, comme dans le domaine de la conception de médicaments et plus particulièrement du Rational Drug Design. L'expert doit être au centre de la tâche de conception de médicament pour la rendre plus efficace et rationnelle, à l’image du succès du jeu sérieux Fold’It, auquel s’ajoute le bénéfice de l’utilisation d’interface tangible capable de manipuler les nombreux degrés de liberté intrinsèques des biomolécules Physical molecular models have long been used in the structural biology and chemistry fields. Despite the emergence of numerical representations offering various and dynamic molecular visualizations to analyze the simulation results, molecular physical models are still being used. Direct manipulation and assembly of physical models ease to create and memorize a mental representation of 3D molecular structures. Interaction techniques to manipulate virtual 3D objects are not reaching the fineness and the benefits of the perceptual cues and manipulation skills of physical models. Moreover, interacting with virtual molecular representations remains a hard task because of the complexity of molecular structures, their size, their flexibility and the various data that define them. In this thesis, we address this issue by designing a molecular tangible interface combining the perks of physical and virtual representations. To match the flexibility and modularity of biomolecules to manipulate, this work met challenges in different scientific fields with the constraint to not use a tracker based system. The first step was to choose, conceive and build a physical model to handle the manifold degrees of freedom of molecules. The second step consisted in creating a numerical representation of mechanical properties of the physical model. Lastly, we needed to develop tracking methods using real-time image processing algorithms in order to control the virtual representation by coupling it to the physical one. New image processing methods have been implemented and evaluated to identify and track atoms in the image space. A Structure from Motion method was designed and adapted to reconstruct in 3D the atom positions by using a small amount of points and by including biochemical knowledge to guide the reconstruction. At last, we address the visualization of physical and dynamic virtual representations, sometimes co-localized in an Augmented Reality context. High performance visualization methods adapted to this context have been developed to enhance shape and cavity perception, two major specifics of biological molecules. For instance, ambient occlusion or sphere raycasting with dynamic shadows can augment a physical object taking the real illumination of the scene for a better insertion in an Augmented Reality context. The impact of this work targets both the education in molecular biology and the research field: the rational drug design field could benefit from the expertise of the user to optimize the design of drugs by manipulating biomolecule's numerous degrees of freedom using a tangible interface. Just like Fold'It is contributing to solve the folding problem, a similar approach could be used to solve the molecular docking problem using advanced manipulation interfaces

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27

Quero, Franck. "Interfacial micromechanics of bacterial cellulose bio-composites using Raman spectroscopy." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/interfacial-micromechanics-of-bacterial-cellulose-biocomposites-using-raman-spectroscopy(080c8304-4625-4c92-a5fb-8eff52bb1a13).html.

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An improved method to evaluate Young's modulus of bacterial cellulose (BC) nanofibrils is presented. This estimation takes into account polarisation configurations, nanofibril orientation and tensile deformation axis direction. A range of 79 - 88 GPa has been obtained showing their great potential to be used as reinforcement in composite materials. BC bio-composites, constituted of a BC layer embedded in-between two matrix layers, have been prepared by compression moulding. The stress-transfer from the matrix to the reinforcement has been quantified using Raman spectroscopy. This has been carried out by following the shift of the Raman band initially located at a wavenumber position of ~1095 cm-1. Polylactide (PLA) was chosen as matrix material due to its biodegradability and bio-sourced origin. Transparent polylactide films were obtained in specific processing conditions to suppress crystallisation. This allowed the laser to penetrate the matrix and interact with the upper layer of BC networks. Several factors that could affect the interface in these composites have been studied. The influence of the culturing time of BC networks on the composite interfaces has been investigated. Higher Raman band shift rates with respect to strain and stress have been measured for composites manufactured using BC networks having a low culturing time. This led to enhanced coupling between PLA and the upper layer of BC networks. Scanning electron microscopy imaging of the tensile fracture surface of these composites revealed that delamination between the BC layers was occurring rather than failure at the BC/PLA interface. Cross-linking of BC networks using glyoxal was performed to consolidate their layered structure. Raman spectroscopy was used to probe the stress-transfer of unmodified and cross-linked BC networks. These data revealed that cross-linked materials exhibit an enhanced stress-transfer both in the dry and wet states compared to unmodified BC networks. Cross-linked BC networks were used to design composites but no significant stress-transfer improvement was observed. As a result, maleated polylactide (MAPLA) was produced and used as a matrix material in order to consolidate the interface between PLA and both the upper and lower layer of cross-linked BC networks. Composites designed using cross-linked BC networks and MAPLA showed a significant stress-transfer improvement over composites designed using unmodified BC networks and PLA. Also the determination of the bulk tensile mechanical properties of the composites revealed a significant increase of relative Young's modulus. This increase is thought to be due to reduced molecular mobility at both the cross-linked BC/MAPLA interface and between cross-linked BC layers. This is further supported by scanning electron imaging of the tensile fracture surfaces.

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Cardoso, Laura. "Assemblage colloïdal pour l'élaboration de matériaux hybrides polysaccharide-silice. Interactions, interfaces et textures." Thesis, Montpellier, Ecole nationale supérieure de chimie, 2015. http://www.theses.fr/2015ENCM0010.

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L'objectif principal de ce travail de thèse est l'étude de la formation de matériaux hybrides polysaccharides – oxydes métalliques par assemblage colloïdal. Il concerne à la fois la compréhension des mécanismes et l'obtention de nouveaux matériaux et textures. Pour ce faire, nous avons étudié dans un premier temps les suspensions formées par les précurseurs colloïdaux (nano-bâtonnets de chitine, oligomères siloxane). Grâce à la détermination des diagrammes de phases, nous avons montré que ces co-suspensions dans l'éthanol présentent, comme en milieu aqueux, des propriétés d'auto-assemblage conduisant à la formation de mésophases nématiques chirales. Par ailleurs, l'étude rhéologique de ces fluides complexes a montré une forte influence des proportions relatives des deux précurseurs sur la viscosité, mettant en évidence le rôle déterminant des interactions entre colloïdes. Au-delà, la caractérisation par microscopie électronique nous a permis de confirmer la formation de colloïdes hybrides au sein des co-suspensions. Dans un deuxième temps, nous avons élaboré de nouveaux matériaux composites soit en modifiant le précurseur polysaccharide (cellulose vs. chitine), soit en introduisant de nouveaux précurseurs de phases inorganiques (Al2O3, TiO2, ZnS). La caractérisation de ces matériaux nous a permis d'évaluer le rôle de la chimie de surface, de la nature et de la taille des précurseurs sur les interactions colloïdales et les propriétés texturales finales. Enfin, nous avons étudié l'effet des procédés de mise en forme – microsphères par atomisation-séchage, fibres par électro-filage, films minces – et de l'application de champs externes – champ électrique, cisaillement – sur les caractéristiques des matériaux. A partir de ces nouveaux résultats, nous proposons un mécanisme de formation qui permet d'envisager la synthèse de matériaux fonctionnels dont les propriétés seraient ajustées selon les applications visées (catalyse, propriétés mécaniques…) The major aim of this PhD thesis has been to study the formation of polysaccharides metal oxides hybrid materials through colloidal assembly. It concerns both the understanding of the mechanisms and the obtention of new materials and textures. To that purpose, we first studied suspensions of the colloidal precursors (chitin nanorods and siloxane oligomers). By mapping out the phase diagrams, we demonstrated that co-suspensions in ethanol exhibit self-assembly properties, similar to those obtained with chitin in aqueous medium, leading to the formation of chiral nematic mesophases. Besides, the rheological study of these complex fluids showed a great influence of the relative proportions of the precursors upon viscosity, hence revealing the major role played by colloidal interactions. Moreover, electron microscopy observations allowed us to confirm the formation of hybrid nanorods colloids made of chitin and silica within the co-suspensions. Then, we elaborated new composite materials either by changing the polysaccharide precursor (cellulose vs. chitin) or by introducing new precursors of inorganic phases (Al2O3, TiO2, ZnS). The characterization of these materials allowed us to estimate the impact of precursors' characteristics (surface chemistry, nature and size) on colloidal interactions and final textural properties. Lastly, we investigated the influence of the materials morphology and processing method – microspheres by spray-drying, fibers by electrospinning, thin films – and application of external fields – electric field, shearing – on the obtained materials characteristics. Based on these new results, we propose a mechanism of formation which enables us to envision the synthesis of functional materials with properties adjusted to intended applications (catalysis, mechanical properties…)

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Hayat, Zain. "Propriétés optiques, organisation moléculaire et dynamique des interfaces de microgouttelettes par un dispositif de détection optofluidique utra-sensible à large bande spectrale." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLN053/document.

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La microfluidique diphasique permet la production et la manipulation de millions de gouttelettes hautement monodisperses, chacune d'entre elles peut servir de microréacteur indépendant. Cette technologie offre de grandes perspectives dans de nombreux domaines scientifiques et industriels (principalement en biotechnologie). Les gouttelettes peuvent être produites, analysées et manipulées à très haut débit grâce notamment à des méthodes optiques. De nombreuses études ont été menées pour améliorer cette technologie et ses applications mais une compréhension approfondie des processus dynamiques complexes se produisant à l'interface des gouttelettes et du fluide porteur (huile) n'est toujours pas bien comprise. Au cours de cette thèse, nous nous sommes intéressés au développement d’une nouvelle approche optofluidique permettant une meilleure analyse de la dynamique et l'organisation moléculaire aux interfaces des gouttelettes dans l’écoulement microfluidique.Notre première étude porte sur la conception et l'utilisation de surfactants photosensibles permettant de stabiliser les gouttelettes et d’induire ensuite leur fusion contrôlée à l'aide d’un laser UV pulsé. La lumière offrant une grande flexibilité, une accordabilité (longueur d’onde et intensité) et une haute résolution spatio-temporelle. Deux approches ont été développées : l’une basée sur la photolyse de molécules photolabiles (processus irréversible) et l’autre basée sur la photo-isomérisation de dérivées d'azobenzène (processus réversible). Le succès de ces deux approches n’était pas évident, car l’irradiation de l’interface à l’échelle microscopique induit des modifications au niveau de la tension interfaciale mais aussi au niveau des processus de diffusion et d’absorption des molécules tensio-actives à l’interface, chacune de ces étapes ajoute une échelle de temps et une distance caractéristique différente. Nos résultats ont permis de déterminer le coefficient de diffusion des surfactants dans la région de l’interface, ainsi que le véritable mécanisme de fusion des gouttes par photo-isomérisation.La deuxième étude porte sur la détection et l'analyse en temps réel des propriétés optiques de l’interface et ce afin de mieux comprendre sa construction, sa dynamique et l'organisation moléculaire dans l’écoulement hydrodynamique. Nous avons pour cela mis au point un système original de détection hautement sensible à large bande, utilisant un réflecteur parabolique ne nécessitant pas l’utilisation de filtres dichroïques. Nous obtenons ainsi une détection en temps réel ultra-sensible de la photoluminescence des gouttelettes sur une large plage spectrale. Nous avons mis en évidence pour la première fois l’apparition d’une émission anti-stokes, thermiquement activée (hot band emission). Celle-ci est principalement localisée au niveau de l’interface. Notre dispositif pourrait constituer un nouvel outil puissant d’analyse permettant de détecter et d’étudier les interfaces liquides avec une très grande résolution spatiale, temporelle et spectrale sans recourir à des techniques complexes d’imagerie et de microscopie optique. Nous montrons par exemple que, contrairement à la microscopie optique, l’émission anti-stokes mise en évidence permet de détecter la formation de vésicules (émulsion double) en temps réel et à très haut débit.Lors de la dernière étude, nous nous intéressons à la diffusion de colorants à travers des bicouches biomimétiques dans des systèmes microfluidiques. Deux approches ont été abordées, celle des bicouches à l’interface de microgouttes (Droplet Interface Bilayer) et celle des émulsions doubles (eau/huile/eau). Nos résultats préliminaires montrent que de tels systèmes constituent de bons modèles pour l’étude du transport de molécules et de médicaments à travers des membranes biologiques Droplet microfluidics offers tremendous applications and prospects in many scientific and industrial fields (mainly in biotechnology). The technology enables for the fabrication and manipulation of millions of highly monodisperse microdroplets, each of which may be regarded as an independent micro-reactor. Droplets may be produced, monitored, and manipulated at kHz rates, using mainly optical (optofluidics) methods. Numerous studies have been conducted to improve the technology but a thorough understanding of the complex fundamental dynamical processes occurring at the droplets interface are still not well understood. During this PhD work, we focused on the development of new optofluidics approaches for a better understanding of the dynamics and the molecular organization at the droplets interface during droplets production and droplets transport in microfluidic channels and chambers (traps).Our first study concerned the design and use of a droplet-stabilizing photoactive surfactant for a controlled merging of droplets using a ps UV-laser. This is particularly attractive approach since light provides flexibility, wavelength/intensity tunability and high temporal/spatial resolutions. We investigated two different methods: photolysis of photolabile molecules (irreversible process) and photo-isomerization of azobenzene derived molecules (reversible process). The success of approach was far from trivial, since illumination at the microscale induces changes not only in the dynamics of the interfacial tension but triggers also changes in diffusion and absorption of surfactant molecules at the droplets interface, each partial step adding a typical time and length-scale. Analysis of the measured merging time (found at the ms time scale) allowed for the determination of the diffusion coefficient of surfactant molecules around the droplet interface. Another important result was the first experimental demonstration of the mechanism of the light-driven merging process using photo-isomerization. It was found to rely on a subtle opto-mechanical process induced by the switching between trans and cis isomers of azobenzene surfactant molecules under illumination.In our second study, we focused on the real-time detection and analysis of the optical properties of dyes at the droplets interfaces, in order to better understand the building, the dynamics and the molecular organization of the droplet interface in the flow. For this aim, we developed an original broadband highly sensitive detection system, using an off-axis full VIS spectrum - collection, reflection and detection scheme. Our setup enables to achieve a real-time detection of droplets photo-luminescence over a large spectral range and at the ms timescale and to show for the first time the occurring of a thermally activated hot band anti-stokes shift emission. The later was found to localize mainly at the droplets interfaces. Based on this original result, we propose that our optofluidic system may serve as a new analysis tool to detect and study soft interfaces without the aid of optical imaging/recording techniques. The observed hot band anti-stokes shift is shown to be suitable for instance to detect and discriminate between flowing droplets and vesicles (or double emulsions) in a real-time and high throughput detection mode.In the last study, we were particularly interested in the study of mass transport and diffusion of dyes across biomimetic bilayers systems. Two major approaches were addressed, the droplet-interface-bilayer (DIB) and solvent evaporated water/oil/water double emulsions. Both techniques required rigorous design and micro-fabrication characterization. Preliminary results show that such systems may lead to the development of smart applications in soft-bio-mimetic membrane’s design, mass transport and drug carriers studies

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30

Doran, Brian. "Preparation and characterization of Ribonucleic acid (RNA)/inorganic materials interfaces using photoemission spectroscopy." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000385.

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31

Corneci, Magdalena Carla. "Fonctionnement tribologique des articulations synoviales pathologiques : Rôle des interfaces phospholipidiques." Thesis, Lyon, INSA, 2012. http://www.theses.fr/2012ISAL0083.

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Afin d’améliorer l’efficacité des traitements des pathologies articulaires, en tenant compte de leur complexité et de leur ampleur, des études récentes ont mis en évidence le rôle des assemblages lipidiques associés à la structure discontinue du fluide synovial dans le contrôle du fonctionnement tribologique articulaire. Ceci à conduit à la mise au point d’un modèle tribologique ex vivo (thèse AM Sfarghiu, 2006), proposant un « motif élémentaire » de la biolubrification articulaire, constitué de l’empilement d’interfaces phospholipidiques et de couches aqueuses. En utilisant ce modèle, l’objectif de ce travail a été d’étudier l’évolution des interfaces phospholipidiques du fluide synovial en présence de pathologies. Pour ce faire, une méthodologie nano-bio-tribologique alliant des analyses biochimiques, physicochimiques, nano-mécaniques et tribologiques a été utilisée. Les résultats de ces analyses montrent : l’influence de la faible rugosité des surfaces frottantes caractérisant les stades précoces des pathologies et celle des propriétés des interfaces phospholipidiques (liées à la variation de leur composition) sur la résistance mécanique, l’évolution au cours du frottement et la dégradation in situ des assemblages lipidiques des fluides synoviaux pathologiques. Le comportement des assemblages lipidiques est accentué par l’action des enzymes associées aux pathologies. Par conséquent, le fonctionnement articulaire dépend de la résistance mécanique des interfaces phospholipidiques et pour obtenir des coefficients de frottement très bas, l’accommodation de vitesse doit s’effectuer au niveau des couches d’hydratation qui entourent les ions présents dans la couche aqueuse. Ces résultats permettront de comprendre à court terme l’évolution des interfaces phospholipidiques dans les pathologies articulaires et, à plus long terme le bon enchaînement cause/conséquence responsable d’une pathologie articulaire afin de développer des traitements plus efficaces, ciblés et non prothétiques In order to improve the effectiveness of joint diseases’ treatments, given their complexity and magnitude, recent studies have highlighted the role of lipid assemblies associated with the discontinuous structure of the synovial fluid (SF) in the tribological performance of joint operation. Thus, an ex vivo tribological model (AM Sfarghiu, PhD thesis, 2006) providing a "basic pattern" for joint biolubrification was developed. It consists of the stack of phospholipidic interfaces and aqueous layers. Using this model, the objective of this work was to study the evolution of phospholipidic interfaces of SF within pathological state. Therefore, a nano-bio-tribological methodology combining biochemical, physicochemical, nano-mechanical and tribological analysis was used. The results of these analyses show: the influence of even small rubbing surfaces’ roughness characteristics of early stage illness and that of phospholipidic interfaces’ properties (related to their composition change) on the mechanical strength, changes in friction and in situ degradation of lipidic assemblies of pathological SF. The tribological operation is highlighted by enzymes’ associated with diseases. Thus, joint operation depends on the mechanical strength of phospholipidic interfaces and to obtain very low friction coefficients, velocity accommodation must be done at the level of hydration layers surrounding ions in the aqueous solution. These results would therefore allow better understanding of the evolution of phospholipidic interfaces in joint diseases and of the proper cause/consequence sequence responsible for a joint disease in order to develop more effective, targeted and non prosthetic treatments

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32

Corneci, Magdalena. "Fonctionnement tribologique des articulations synoviales pathologiques : rôle des interfaces phospholipidiques." Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00766779.

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Afin d'améliorer l'efficacité des traitements des pathologies articulaires, en tenant compte de leur complexité et de leur ampleur, des études récentes ont mis en évidence le rôle des assemblages lipidiques associés à la structure discontinue du fluide synovial dans le contrôle du fonctionnement tribologique articulaire. Ceci à conduit à la mise au point d'un modèle tribologique ex vivo (thèse AM Sfarghiu, 2006), proposant un " motif élémentaire " de la biolubrification articulaire, constitué de l'empilement d'interfaces phospholipidiques et de couches aqueuses. En utilisant ce modèle, l'objectif de ce travail a été d'étudier l'évolution des interfaces phospholipidiques du fluide synovial en présence de pathologies. Pour ce faire, une méthodologie nano-bio-tribologique alliant des analyses biochimiques, physicochimiques, nano-mécaniques et tribologiques a été utilisée. Les résultats de ces analyses montrent : l'influence de la faible rugosité des surfaces frottantes caractérisant les stades précoces des pathologies et celle des propriétés des interfaces phospholipidiques (liées à la variation de leur composition) sur la résistance mécanique, l'évolution au cours du frottement et la dégradation in situ des assemblages lipidiques des fluides synoviaux pathologiques. Le comportement des assemblages lipidiques est accentué par l'action des enzymes associées aux pathologies. Par conséquent, le fonctionnement articulaire dépend de la résistance mécanique des interfaces phospholipidiques et pour obtenir des coefficients de frottement très bas, l'accommodation de vitesse doit s'effectuer au niveau des couches d'hydratation qui entourent les ions présents dans la couche aqueuse. Ces résultats permettront de comprendre à court terme l'évolution des interfaces phospholipidiques dans les pathologies articulaires et, à plus long terme le bon enchaînement cause/conséquence responsable d'une pathologie articulaire afin de développer des traitements plus efficaces, ciblés et non prothétiques.

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Senouci, Mohamed. "Sélection adaptative de la technologie réseau pour le transport de données dépendant du contexte." Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1126.

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Les travaux développés dans cette thèse ont pour cadre général la mise en œuvre d’approches adaptatives permettant de faire évoluer la gestion du réseau en migrant d’une vue "centrée réseau" où l’on se contentait uniquement des paramètres issus du réseau lui-même, vers une vue "centrée utilisateur". Plus particulièrement, ces travaux se sont focalisés sur un des composants principaux de l’ensemble de la chaîne de traitement et de transport, celui de la sélection de la meilleure interface réseau embarquée dans le terminal mobile, l’objectif étant de répondre au mieux aux contraintes imposées par l’environnement. Ces travaux reposent sur une approche décisionnelle dynamique tenant compte de changements dans les paramètres réseaux et des besoins et préférences des utilisateurs au regard des services qui leur sont proposés. En effet, dans l’environnement actuel, se caractérisant par une multiplicité de technologies, d’applications et d’utilisateurs, les terminaux mobiles sont équipés de plusieurs interfaces réseaux. Ces derniers donnent ainsi la possibilité aux utilisateurs de pouvoir basculer dynamiquement d’une interface à une autre dans l’objectif d’assurer une connexion satisfaisant le mieux possible leurs besoins en termes de services en tout lieu, à tout moment et de la meilleure manière possible (ABC, Always Best Connected). Les approches mises en œuvre dans le cadre de la thèse ont permis d’associer simultanément chaque flux d’application à l’interface la plus appropriée de manière à optimiser les performances globales du système. Ainsi, ces travaux ont mené à la proposition d’approches hybrides ayant pour cadre de départ la technique TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) et en y intégrant des modèles issus de la théorie des fonctions de croyance. Pour l’association flux/interface, une proposition basée sur des algorithmes bio-inspirés a été faite dans le cadre de ces travaux. Les résultats obtenus, à la fois par simulation et sur un cas d’usage réel en lien avec le domaine de la santé connectée, ont montré l’efficacité des approches proposées The work developed in this dissertation has as a general framework the implementation of adaptive user-centric approaches for network interface selection (NIS) and flow/interface association (FIA) in Heterogeneous Wireless Networks (HWNs). The NIS mechanism relies on a dynamic decision approach that considers the change in networks’ parameters and users’ needs and preferences for their current applications. In a heterogeneous environment, the mobile terminals that are equipped with multiple network interfaces provide the possibility for mobile end-users to switch among available network interfaces and select the one that best fulfills their needs anywhere at any time which is known as Always Best Connected (ABC). The approaches proposed in this thesis allowed to associate simultaneously each application flow to its suitable interface in a way that best maximizes the global system performance. This work has led to the proposal of hybrid approaches originating from TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) and integrating models from the belief functions theory for the NIS. Concerning the FIA, a proposal based on bio-inspired algorithms was made as part of this work. Experimental results based on synthetic datasets and an experimental test bed for health monitoring showed the effectiveness of the proposed approaches

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Bai, Hongjuan. "Bio-colloidal transfer in saturated and unsaturated porous media : influence of the physical heterogeneity of the porous medium and cell properties on bacteria transport and deposition mechanisms." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2336/document.

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La compréhension du transport et du dépôt bio-colloïdal dans un milieu poreux présente un grand intérêt dans les applications environnementales, en particulier pour le contrôle de la bio-remédiation des sols et la protection des ressources en eau souterraine. Afin de mieux évaluer et prévenir les risques de contamination de la nappe phréatique et de proposer des solutions adéquates de remédiation, il est nécessaire d’avoir une bonne compréhension des mécanismes qui contrôlent le transport et le dépôt des bactéries dans les milieux poreux saturés et non saturés. L’objectif des ces travaux de thèse est d’étudier le rôle de l’hétérogénéité physique du milieu poreux (distribution granulométrique, porosité…) et de l’hydrodynamique du milieu sur les mécanismes de transport et de dépôt de particules bio-colloïdales, tout en prenant en compte l’impact des propriétés de cellules bactériennes sur ces mécanismes. Des expériences de traçage et d’injection de suspensions bactériennes ont été menées à l’échelle de colonnes de laboratoire dans trois milieux poreux avec une porosité et une distribution de taille de pore distincte. Afin de caractériser l’écoulement dans les milieux poreux, un soluté non-réactif a été utilisé comme traceur de l’eau. Trois souches bactériennes ont été utilisées pour préparer les suspensions bactériennes : une bactérie mobile (Escherichia coli), et deux non mobiles (Klebsiella sp. et R. rhodochrous). La caractérisation des propriétés cellulaires (telles que la taille et la forme des cellules, le potentiel zêta, la motilité et l'hydrophobicité) a été effectuée pour chaque souche. Des simulations numériques ont été réalisées en utilisant le code de calcul HYDRUS-1D afin de modéliser l’écoulement et d’estimer les paramètres de transport et de dépôt des bactéries. Ces derniers ont été explorés afin d'identifier le mode de transport bactérien et les mécanismes physico-chimiques ou physiques impliqués dans le dépôt des bactéries. Des expériences supplémentaires à l'échelle des pores ont été réalisées à l'aide de dispositifs microfluidiques conçus à cet effet. Un calcul théorique des différentes interactions entre les bactéries et le milieu poreux aux interfaces air/eau/solide a été effectué pour compléter les résultats expérimentaux ainsi que ceux issus de la modélisation numérique. Ainsi, les énergies d’interactions telles que les forces de van der Waals, électrostatiques de double couche, hydrophobes, stériques, capillaires et hydrodynamiques, impliquées dans le dépôt de bactéries ont été calculées pour décrire les interactions bactéries-interfaces afin d'identifier leur impact relatif sur le dépôt physico-chimique et physique des bactéries. Les résultats expérimentaux et la modélisation numérique ont mis en évidence un écoulement non uniforme, dépendant de la taille des grains ainsi que de la distribution de la taille des pores du milieu poreux. Pour un milieu poreux donné, l’écoulement devient plus dispersif quand la teneur en eau du milieu diminue. Ceci est dû à l’augmentation de la tortuosité du milieu, du fait de la présence de l’air dans les pores. Le transport des bactéries diffère de celui du traceur de l’eau. Le dépôt bactérien a été fortement influencé par la géométrie du réseau poral du milieu, les propriétés cellulaires et le degré de saturation en eau. Le piégeage physique et physico-chimique sont des mécanismes qui doivent être pris en compte pour bien décrire le dépôt bactérien, mais leur importance sur les mécanismes de dépôt est étroitement liée aux propriétés du milieu poreux et des cellules. Ces travaux mettent en évidence l’effet simultané des propriétés cellulaires, des propriétés physiques (granulométrie et distribution de taille de pores) et de l'hydrodynamique du milieu poreux sur les mécanismes de transport et de dépôt bactérien. Le calcul des différentes énergies d’interaction a permis d’identifier leur importance sur les mécanismes de dépôt bactérien The investigation of the transport and retention of bacteria in porous media has a great practical importance in environmental applications, such as protection of the surface and groundwater supplies from contamination, risk assessment from microorganisms in groundwater, and soil bioremediation. The aim of this study is to gain a fundamental understanding of the mechanisms that control bacteria transport and deposition in saturated and unsaturated porous media. Laboratory tracer and bacteria transport experiments at Darcy scale were performed in three porous media with distinct pore size distribution in order to investigate and quantify water and bacteria transport process under steady state flow conditions. A conservative solute was used as water tracer to characterize water flow pathways through porous media. A gram negative, motile Escherichia coli, a gram negative, non-motile Klebsiella sp. and a gram positive, non-motile R. rhodochrous were selected for the transport experiments. Characterization of cell properties (such as cell size and shape, zeta potential, motility and hydrophobicity) was performed for each strain. Numerical simulations with HYDRUS-1D code were performed to characterize water flow and to estimate bacteria transport and deposition parameters. The later were explored to identify bacteria flow patterns and physicochemical or physical mechanisms involved in bacteria deposition. To provide a better understanding of the mechanisms involved on bacteria transport and deposition, pore scale experiments were carried out by using microfluidic devices, designed for this purpose. The information obtained from laboratory experiments and numerical modeling was improved by theoretical calculation of different interactions between bacteria and porous media at air/water/solid interfaces. DLVO and non-DLVO interactions such as hydrophobic, steric, capillary and hydrodynamic forces involved in bacteria deposition were considered to describe bacteria-interface interactions in order to identify their relative impact on physicochemical and physical deposition of bacteria. Results obtained through both laboratory experiments and numerical simulationsoutlined non-uniform flow pathways, which were dependent on both grain/pore size as well as pore size distribution of the porous media. For a given porous medium, water flow patterns became more non-uniform and dispersive with decreasing water saturation due to the presence of air phase, which lead to an increase of the tortuosity of the flow pathways under unsaturated conditions. Bacteria transport pathways were different from the tracer transport, due to size exclusion of bacteria from smaller pore spaces and bacteria motility. Bacteria deposition was greatly influenced by pore network geometry, cell properties and water saturation degree. Both physical straining and physicochemical attachment should be taken into account to well describe bacteria deposition, but their importance on bacteria deposition is closely linked to porous media and cell properties. The results obtained in this work highlighted the simultaneous role of cell properties, pore size distribution and hydrodynamics of the porous media on bacteria transport and deposition mechanisms. The calculation of DLVO and non-DLVO interactions showed that bacteria deposition in saturated and unsaturated porous media was influenced by both kinds of interactions

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Noon, William H. "Molecular dynamics simulation of bio-fullerene interfaces." Thesis, 2004. http://hdl.handle.net/1911/18676.

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Molecular Dynamics (MD) simulations were employed to study the interaction of fullerene molecules in biological environments. Initial work considers the interaction of peptides with fullerene, where a fullerene specific antibody and a single-walled carbon nanotube (SWNT) wrapped by a peptide was simulated. Results reveal the interface between peptides and fullerene to be dominated by hydrophobic interactions. Also, pi-stacking interactions were a predominant recognition mode. Electrostatic forces primarily defined the shape of the complex around the fullerene. Another study involved the interaction of water with SWNT. Unexpectedly, water was observed to partition within the center of nanotubes. Furthermore, the water organizes into a hydrogen-bonded network that is dependent upon nanotube diameter. The phenomenon parallels the function of transmembrane proteins, and consequently, free energy calculations were completed to consider if nanotubes exhibited selective ion partitioning. Indeed, ions specifically favored certain nanotube indices and selectivity was dependent upon nanotube diameter and ion solvation structure. Much of this thesis analyzes the structure of sodium dodecyl sulfate (SDS) around SWNT. Initial results suggested that nanotubes were encased in a thick micelle that prohibited water from contacting the tube. However, later experimental data suggested a much more dynamic system and therefore new simulation techniques were developed to achieve an improved model. The new methodology was first developed by simulating the aggregation of a random mixture of SDS into micelles of experimentally expected sizes and structures. After successful testing, a random mixture was allowed to aggregate onto a nanotube. The results reveal a random monolayer exists around the tube, but the head groups and water molecules are much closer the tube, which accounts for the more dynamic fluorescence properties observed. Simple geometric modeling and recent fluorescence measurements are also considered to further support the improved model. Finally, the aggregation of polyethylene oxide (PEO) derived polymers around SWNT was completed. Results reveal a much weaker hydrophobic interaction with the tube and consequently much less of the tube is covered by polymer. The findings correlate well with fluorescence and protein adsorption experiments. The structure of the wrapping polymer is also considered, along with the effect of molecular weight.

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Huang, Yimin. "Functional nano-bio interfaces for cell modulation." Thesis, 2020. https://hdl.handle.net/2144/41113.

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Interacting cellular systems with nano-interfaces has shown great promise in promoting differentiation, regeneration, and stimulation. Functionalized nanostructures can serve as topological cues to mimic the extracellular matrix network to support cellular growth. Nanostructures can also generate signals, such as thermal, electrical, and mechanical stimulus, to trigger cellular stimulation. At this stage, the main challenges of applying nanostructures with biological systems are: (1) how to mimic the hierarchical structure of the ECM network in a 3D format and (2) how to improve the efficiency of the nanostructures while decreasing its invasiveness. To enable functional neuron regeneration after injuries, we have developed a 2D nanoladder scaffold, composed of micron size fibers and nanoscale protrusions, to mimic the ECM in the spinal cord. We have demonstrated that directional guidance during neuronal regeneration is critical for functional reconnection. We further transferred the nanoladder pattern onto biocompatible silk films. We established a self-folding strategy to fabricate 3D silk rolls, which is an even closer system to mimic the ECM of the spinal cord. As demonstrated by in vitro and in vivo experiments, such a scaffold can serve as a grafting bridge to guide axonal regeneration to desired targets for functional reconnection after spinal cord injuries. Benefited from the robust self-folding techniques, silk rolls can also be used for heterogeneous cell culture, providing a potential therapeutic approach for multiple tissue regeneration directions, such as bones, muscles, and tendons. For achieving neurostimulation, we have developed photoacoustic nanotransducers (PANs), which generate ultrasound upon excitation of NIR II nanosecond laser light. By surface functionalize PAN to bind to neurons, we have achieved an optoacoustic neuron stimulation process with a high spatial and temporal resolution, proved by in-vitro and in-vivo experiments. Such an application can enable non-invasive, optogenetics free and MRI compatible neurostimulation, which provides a new direction of gene-transfection free neuromodulation. Collectively, in this thesis, we have developed two systems to promote functional regeneration after injuries and stimulate neurons in a minimally invasive manner. By integrating those two functions, a potential new generation of the bioengineered scaffold can be investigated to enable functional and programmable control during the regeneration process.

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Shekar, Siddharth. "Design of custom CMOS amplifiers for nanoscale bio-interfaces." Thesis, 2019. https://doi.org/10.7916/d8-kb2p-zm21.

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The miniaturization of electronics is a technique that holds a lot of potential in improving system performance in a variety of applications. The simultaneous miniaturization of sensors into the nano-scale has provided new ways to probe biological systems. Careful co-design of these electronics and sensors can unlock measurements and experiments that would otherwise be impossible to achieve. This thesis describes the design of two such instrumentation amplifiers and shows that significant gains in temporal resolution and noise performance are possible through careful optimization. A custom integrated amplifier is developed for improving the temporal resolution in nanopore recordings. The amplifier is designed in a commercial 0.18 μm complementary metal-oxide-semiconductor (CMOS) process. A platform is then built with the amplifier at its core that integrates glass-passivated solid-state nanopores to achieve measurement bandwidth over an order of magnitude greater than the state of the art. The use of wavelet transforms for denoising the data and further improving the signal-to-noise ratio (SNR) is then explored. A second amplifier is designed in a 0.18 μm CMOS process for intracellular recordings from neurons. The amplifier contains all the compensation circuitry required for canceling the effects of the electrode non-idealities. Compared to equivalent commercial systems and the state of the art, the amplifier performs comparably or better while consuming orders of magnitude lower power. These systems can inform the design of extremely miniaturized application-specific integrated amplifiers of the future.

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Moretta, Rosalba. "Design, fabrication and characterization of nanostructured hybrid bio/non-bio interfaces for biomolecular interactions study and industrial applications." Tesi di dottorato, 2020. http://www.fedoa.unina.it/13154/1/Moretta_Rosalba_32.pdf.

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Hybrid devices have one or more biological components bioconjugated with functional support surfaces preserving their specific activity and properties. They are extremely interesting from the biotechnological point of view since: 1)They provide a creative way to combine functional properties of different substances into a singular molecular composite; 2) They could show enhanced properties due to the coupling of different elements; 3)Their properties open innovative ways to applications in different fields, such as food, agriculture, medicine and so on. The goal of this PhD thesis is the development of some hybrid-nanocomposites, made of nanostructured materials and biological elements, in which the key issue is the interface between the bio and non-bio components of the systems. Bioconjugated nanostructured materials reveal peculiar physical and chemical properties that can boost their use in biotechnological applications. Inorganic nanoparticles, in particular those based on noble metals and semiconductors in native form or oxide, are becoming common tools in many popular fields of investigation such as nanomedicine, imaging, environmental monitoring and biomolecular sensing. Porous silicon (PSi), Gold nanoparticles (AuNPs) and Zinc Oxide (ZnO) are three highly-performing nanostructured systems whose features have been exploited in this thesis. The research approach used in this work thesis is focused on the synthesis and fabrication of nanostructured support materials, in planar or in nanoparticle shapes, followed by the functionalization and passivation of the material surfaces. Finally, biological elements are immobilized on the solid supports for specific studies and applications. Different hybrid devices have been developed in this work for applications in several research areas, in particular: Hybrid silicon-based device for the detection of Brugada Syndrome for diagnostic purposes; Luminescent silicon nanoparticles as label-free bioprobes for fluorescent bioimaging applications; Hybrid gold-copper nanoparticles as promising contrast agent in nuclear magnetic resonance; Gold nanoparticles complexed to an antimicrobial peptide to enhance the antibacterial activity of the peptide. The results obtained in each case highlighted the innovative potentialities of these nano-complexes in solving problems and breaking barriers in different ambits, spanning from diagnostic to healthcare.

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Tristl, Matthias Hermann [Verfasser]. "Design of bio-mimetic interfaces based on genetically engineered oligomers of lumazine synthase / Matthias Hermann Tristl." 2004. http://d-nb.info/972319255/34.

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Castro, João Filipe Oliveira de. "Projecto de interface indutivo para aplicação em micro-dispositivos médicos." Master's thesis, 2010. http://hdl.handle.net/10216/58549.

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Castro, João Filipe Oliveira de. "Projecto de interface indutivo para aplicação em micro-dispositivos médicos." Dissertação, 2010. http://hdl.handle.net/10216/58549.

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Sultan, A. M., Z. C. Westcott, Zak E. Hughes, et al. "Aqueous peptide-TiO2 interfaces: isoenergetic binding via either entropically or enthalpically driven mechanisms." 2016. http://hdl.handle.net/10454/15854.

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Yes A major barrier to the systematic improvement of biomimetic peptide-mediated strategies for the controlled growth of inorganic nanomaterials in environmentally benign conditions lies in the lack of clear conceptual connections between the sequence of the peptide and its surface binding affinity, with binding being facilitated by noncovalent interactions. Peptide conformation, both in the adsorbed and in the nonadsorbed state, is the key relationship that connects peptide-materials binding with peptide sequence. Here, we combine experimental peptide–titania binding characterization with state-of-the-art conformational sampling via molecular simulations to elucidate these structure/binding relationships for two very different titania-binding peptide sequences. The two sequences (Ti-1, QPYLFATDSLIK; Ti-2, GHTHYHAVRTQT) differ in their overall hydropathy, yet via quartz-crystal microbalance measurements and predictions from molecular simulations, we show these sequences both support very similar, strong titania-binding affinities. Our molecular simulations reveal that the two sequences exhibit profoundly different modes of surface binding, with Ti-1 acting as an entropically driven binder while Ti-2 behaves as an enthalpically driven binder. The integrated approach presented here provides a rational basis for peptide sequence engineering to achieve the in situ growth and organization of titania nanostructures in aqueous media and for the design of sequences suitable for a range of technological applications that involve the interface between titania and biomolecules. AFOSR grant FA9550-12-1-0226; AFOSR for funding via FA9550-13-1-0040

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Hughes, Zak E., and T. R. Walsh. "What makes a good graphene-binding peptide? Adsorption of amino acids and peptides at aqueous graphene interfaces." 2015. http://hdl.handle.net/10454/15961.

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Yes Investigation of the non-covalent interaction of biomolecules with aqueous graphene interfaces is a rapidly expanding area. However, reliable exploitation of these interfaces in many applications requires that the links between the sequence and binding of the adsorbed peptide structures be clearly established. Molecular dynamics (MD) simulations can play a key role in elucidating the conformational ensemble of peptides adsorbed at graphene interfaces, helping to elucidate these rules in partnership with experimental characterisation. We apply our recently-developed polarisable force-field for biomolecule–graphene interfaces, GRAPPA, in partnership with advanced simulation approaches, to probe the adsorption behaviour of peptides at aqueous graphene. First we determine the free energy of adsorption of all twenty naturally occurring amino acids (AAs) via metadynamics simulations, providing a benchmark for interpreting peptide–graphene adsorption studies. From these free energies, we find that strong-binding amino acids have flat and/or compact side chain groups, and we relate this behaviour to the interfacial solvent structuring. Second, we apply replica exchange with solute tempering simulations to efficiently and widely sample the conformational ensemble of two experimentally-characterised peptide sequences, P1 and its alanine mutant P1A3, in solution and adsorbed on graphene. For P1 we find a significant minority of the conformational ensemble possesses a helical structure, both in solution and when adsorbed, while P1A3 features mostly extended, random-coil conformations. In solution this helical P1 configuration is stabilised through favourable intra-peptide interactions, while the adsorbed structure is stabilised via interaction of four strongly-binding residues, identified from our metadynamics simulations, with the aqueous graphene interface. Our findings rationalise the performance of the P1 sequence as a known graphene binder. veski

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Hughes, Zak E., R. Kochandra, and T. R. Walsh. "Facet-specific adsorption of tripeptides at aqueous au interfaces: open questions in reconciling experiment and simulation." 2017. http://hdl.handle.net/10454/15821.

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Yes The adsorption of three homo-tripeptides, HHH, YYY, and SSS, at the aqueous Au interface is investigated, using molecular dynamics simulations. We find that consideration of surface facet effects, relevant to experimental conditions, opens up new questions regarding interpretations of current experimental findings. Our well-tempered metadynamics simulations predict the rank ordering of the tripeptide binding affinities at aqueous Au(111) to be YYY > HHH > SSS. This ranking differs with that obtained from existing experimental data which used surface-immobilized Au nanoparticles as the target substrate. The influence of Au facet on these experimental findings is then considered, via our binding strength predictions of the relevant amino acids at aqueous Au(111) and Au(100)(1 × 1). The Au(111) interface supports an amino acid ranking of Tyr > HisA ≃ HisH > Ser, matching that of the tripeptides on Au(111), while the ranking on Au(100) is HisA > Ser ≃ Tyr ≃ HisH, with only HisA showing non-negligible binding. The substantial reduction in Tyr amino acid affinity for Au(100) vs Au(111) offers one possible explanation for the experimentally observed weaker adsorption of YYY on the nanoparticle-immobilized substrate compared with HHH. In a separate set of simulations, we predict the structures of the adsorbed tripeptides at the two aqueous Au facets, revealing facet-dependent differences in the adsorbed conformations. Our findings suggest that Au facet effects, where relevant, may influence the adsorption structures and energetics of biomolecules, highlighting the possible influence of the structural model used to interpret experimental binding data. Air Office of Scientific Research, Grant No. FA9550-12-1-0226

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Luk, Yan-Yeung. "I. Bio-inertness and stereochemical control of cell adhesion on chiral surfaces ; and II. Surface chemistry of self-assembled monolayers and nano-colloids /." 2001. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3006529.

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DI, FLUMERI GIANLUCA. "Electroencephalography-based measures of human mental workload in operational environments for the development of passive Brain-Computer Interfaces." Doctoral thesis, 2018. http://hdl.handle.net/11573/1067201.

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È possibile esaltare le prestazioni di un operatore stimando il suo carico di lavoro mentale dalla propria attività cerebrale, ed usare questa informazione per adattare le funzionalità dell’interfaccia che sta utilizzando? Questa è la domanda sperimentale a cui la mia attività di ricerca del Dottorato ha provato a dare una risposta. Anche se in maniera non quantificata, è ampiamente accettata l’idea che le risorse cognitive del cervello umano siano limitate. In funzione della quantità di risorse cognitive, in altre parole del carico di lavoro mentale, dedicate al compito principale, la capacità umana di affrontare ulteriori eventi inaspettati potrebbe diminuire drasticamente. È stato dimostrato che gli uomini possono raggiungere le proprie migliori prestazioni solo mantenendo il proprio carico di lavoro mentale all’interno di un intervallo ottimale, altrimenti aumenta la probabilità che commettano errori. Sfortunatamente, l’errore umano è una delle principali cause di incidenti e catastrofi non naturali. Per tale motivo, la ricerca neuroscientifica sta dando un importante contributo allo sviluppo di Interfacce Cervello-Computer in grado di riconoscere lo stato mentale dell’utente e di aiutarlo se necessario. In tale contesto, la mia attività di ricercar aveva lo scopo di sviluppare un metodo in grado di valutare online il carico di lavoro mentale dell’utente, sulla base della sua attività cerebrale misurata attraverso Elettroencefalografia, in ambienti operativi, affrontando tutti quei problemi relativi all’eseguire misure neurofisiologiche affidabili al di fuori dei contesti controllati propri dei laboratori. Il metodo sviluppato (brevettato) è stato con successo validato in tre differenti ambienti operative, ossia il controllo di traffico aereo, la guida di auto e la chirurgia assistita da robot. Inoltre, esso è stato applicato online in una reale applicazione di Interfaccia Cervello Computer, dove la piattaforma operative variava il suo livello di automazione sulla base del carico di lavoro mentale, misurato attraverso tecnica EEG, dell’operatore. Is it possible to enhance the performance of an operator by inferring his/her mental workload online from his brain activity? Also, would be possible to use such information to adapt the functionalities of the operative interface he/she is interacting with? This is the experimental question that my PhD research activity tried to answer. Even if not quantified, it is widely accepted the assumption that the human brain cognitive resources are limited. Depending on the amount of cognitive resources, i.e. the mental workload, committed to the main task, the human capacity to face additional unexpected events could dramatically decrease. It was demonstrated that humans could achieve their best performance only if maintaining their mental workload within an optimum range, otherwise they will be more prone to commit errors. Unfortunately, the human error is one of the main causes of accidents and no-natural catastrophes. Therefore, neuroscientific research is giving an important contribute in the development of Brain-Computer Interfaces able to recognize the user’s mental state covertly (i.e. without interfering with his/her main activity) and to help him if needed. In this context, my research activity aimed to develop a method able to evaluate, even online, the user’s mental workload, on the basis of his/her brain activity measured by Electroencephalography, in operational environments, facing all those issues related to perform reliable neurophysiological measures outside the laboratory controlled conditions. The developed method (patented) has been successfully validated in three different operational environments, i.e. the Air Traffic Management, the car driving and the robot-assisted surgery. Also, it has been applied online in a real application of Brain Computer Interface, where the operative platform changed its behaviour according on the EEG-based measure of the actual operator’s mental workload level.

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Dissertations / Theses on the topic 'Bio-Interfaces'

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