Dissertations / Theses on the topic 'Silica coated magnetic particles'

Magnetic nanoparticles (MNPs) hold great promise in the fields of biology and medicine. The synthesis of functional MNPs with precisely controlled crystallographic, physicochemical, and magnetic properties on a large scale still remains the challenge today. This thesis reports the exploration of liquid-fed flame spray pyrolysis (FSP) in the synthesis of functional MNPs, their surface modifications, and potential bio-applications. Superparamagnetic and ferromagnetic maghemite (γ-Fe2O3) nanoparticles, and silica-coated maghemite (SiO2/γ-Fe2O3) nanocomposites were synthesised using FSP. The size of γ-Fe2O3 was controllable from 6 to 53 nm, with morphology evolving from a disordered near-spherical shape to fully ordered 2-D hexagonal/octagonal platelet. The saturation magnetisation (Ms) increased from 21 to 74 emu/g with increasing particle size, up to 13 nm when Ms approached the bulk γ-Fe2O3 characteristics. In the case of SiO2/γ-Fe2O3, three distinct morphologies, namely the single segregated γ-Fe2O3 core- SiO2 shell, transitional mixed morphologies, and multi γ-Fe2O3 cores embedded in submicron SiO2 shell, were obtained. The core size, composite size, and morphology of γ- Fe2O3 were tunable by varying %SiO2 loading and the use of a quartz tube enclosure during flame synthesis. The magnetic behaviour correlated well with the crystal microstructure. Following the core particle design, protein adsorption-desorption behaviour on FSP-madeMNPs was studied. Bovine serum albumin (BSA) adsorption was found to follow the Langmuir isotherm, with high binding capacities (150−348 mg BSA/g particle) and fast association constants. Electrostatically governed BSA orientations were proposed for different particle-buffer systems. The adsorbed BSA was effectively recovered by pH-shift using K2HPO4. Subsequently, terminal amine, aldehyde, carboxylic, epoxy, mercapto and maleimide functionality were anchored onto the FSP-made γ-Fe2O3 particles. These versatile functional groups led to conjugation of active trypsin. The immobilised trypsin exhibited superior durability with >60% residual activity after one week, and excellent reusability for >5 cycles. The trypsin-conjugated MNPs are promising carriers in proteomics, demonstrating good substrate specificity with equivalent or better sequence coverage compared to free trypsin in insulin and BSA digestion. In another application, a refined silanisation procedure simultaneously reduced γ-Fe2O3 to Fe3O4, and generated thiol enriched surface for matrix metalloproteinase-2 (MMP-2) conjugation. The highly active MMP-2-conjugated MNPs could potentially enhance the interstitial transport of macromolecule/nanoparticles in drug delivery.

Mesoporous silica particles are of significant interest for biomedical applications due to their good general biocompatibility compared to other nanoparticle matrices such as quantum dots, high specific surface areas up to 1000 m2/g, and extreme synthetic tunability in terms of particle size, pore size and topology, core material, and surface functionalization. For one application, drug delivery, mesoporous silica nanoparticles (MSNs) of two pore structures, MCM-41 – parallel, hexagonally ordered pores approximately 3 nm in diameter – and wormhole (WO) – interconnected, disordered pores also approximately 3 nm in diameter – were synthesized with particle diameters under 100 nm. Additionally, a magnetic Fe3O4 nanoparticle core was incorporated into Fe3O4-core WO-MS-shell particles. The particles were loaded with doxorubicin, a chemotherapeutic, and the drug release into phosphate buffered saline (PBS, 10 mM, pH 7.4) at 37 °C was monitored by fluorescence spectroscopy. The data were fit to three models: Korsmeyer-Peppas, first order exponential release, and Weibull. The Korsmeyer-Peppas model provided useful information concerning the kinetics and mechanism of drug release from each MSN type. A small but statistically significant difference in the release kinetics was found due to the different pore topologies. A much larger kinetic effect was observed due to the inclusion of an iron oxide core. Applying a static magnetic field to the Fe3O4-core WO-MS shell particles did not have a significant impact on the doxorubicin release. This is the first time that the effects of pore topology and iron oxide core have been isolated from pore diameter and particle size for these materials. In vitro cell studies were conducted to determine the cytotoxicity of the bare and doxorubicin-loaded materials against three cancerous cell lines – A549 human lung carcinoma cells, HEC50CO human endometrial cancer cells, and CT26 mouse colon cancer cells. The MCM-41 and WO MSNs generally displayed similar toxicities within each cell line, and the Fe3O4-core WO-MS shell particles were less toxic. Doxorubicin-loaded particles generally displayed greater toxicity than bare MSNs, but the A549 cells were very resistant to all concentrations of MSNs tested. For another biomedical application, tissue phantom development, mesoporous silica particles with approximately 10 μm diameters and C18 surface functionalization were evaluated for their use as a substrate for optical tissue phantoms. Tissue phantoms are synthetic imitations of biological material, and C18-modified silica provides a substrate that is simple to load with optically active biological molecules. The molecules are then hydrophobically trapped to maintain a clear optical boundary between the biological loading within the particle and an aqueous suspension gel. Several preparation techniques were evaluated for the dispersal of hydrophobic particles in aqueous media, and qualitative analysis indicated that surfactant coating of the outer surface could fully disperse the hydrophobic particle while maintaining the clear optical boundary. A novel analysis was developed to provide a single numerical indicator of clustering for a quantitative assessment of particle dispersal in tissue phantoms.

The magnetic separation approach has several advantages compared with conventional separation methods
it can be performed directly in crude samples containing suspended solid materials without pretreatment, and can easily isolate some biomolecules from aqueous systems in the presence of magnetic gradient fields. This thesis focused on the development of new class of magnetic separation material particularly useful for the separation of histidine-tagged proteins from the complex matrixes through the use of imidazole side chains of histidine molecules. For that reason surface modified cobalt ferrite nanoparticles which contain Ni-NTA affinity group were synthesized. Firstly, cobalt ferrite nanoparticles with a narrow size distribution were prepared in aqueous solution using the controlled coprecipitation method. In order to obtain small size of agglomerates two different dispersants, oleic acid and sodium chloride, were tried. After obtaining the best dispersant and optimum experimental conditions, ultrasonic bath was used in order to decrease the size of agglomerates. Then, they were coated with silica and this was followed by surface modification of these nanoparticles by amine in order to add functional groups on silica shell. Next, &ndash
COOH functional groups were added to silica coated cobalt ferrite magnetic nanoparticles through the NH2 groups. After that N&alpha
,N&alpha
-Bis(carboxymethyl)-L-lysine hydrate, NTA, was attached to carboxyl side of the structure. Finally, nanoparticles were labeled with Ni (II) ions. The size of the magnetic nanoparticles and their agglomerates were determined by FE-SEM images, particle size analyzer, and zeta potential analyzer (zeta-sizer). Vibrational sample magnetometer (VSM) was used to measure the magnetic behavior of cobalt ferrite and silica coated cobalt ferrite magnetic nanoparticles. Surface modifications of magnetic nanoparticles were followed by FT-IR measurements. ICP-OES was used to find the amount of Ni (II) ion concentration that was attached to the magnetic nanoparticle.

This thesis studies the formation and decomposition of methane hydrate crystal in an unconsolidated bed of silica sand particles. Hydrate processes were visualized by taking advantage of the ¹H magnetic resonance imaging technique, and the integrated intensity of magnetic resonance images was used to quantify the rate and kinetics. For all of the experiments, the initial pressure was 8 MPa and the temperature was kept constant at 1℃. Beds composed of 2 grams of sand were saturated with different amounts of water (0.44, 0.33, 0.22 and 0.11 mL) in order to examine the effect of water content of the bed on the kinetics of hydrate formation in porous media. Also, the effect of particle size was investigated by forming hydrate in beds with different particle size ranges (210-297, 125-210, 88-177 and <74 µm). It was found that the hydrate formation process in a bed of silica sand particles can be divided into three stages: induction time, non-uniform growth and uniform growth. During the first stage, methane molecules dissolved and diffused in water. After formation of the first crystals of hydrate at the end of the induction period (nucleation point), hydrate formation proceeded through a combination and competition between nucleation and growth, and multiple nucleation occurred. During the last stage, no obvious nucleation was observed and hydrate formation continued only through the growth of the crystals which had already been formed during the previous stages. The rate of hydrate formation was found to be faster in beds with smaller particles and lower water content.

Ce doctorat porte sur la fonctionnalisation de silices colloïdales en vue de la rétention de micropolluants métalliques dans des effluents. Les nanoparticules et microparticules ouvrent des potentialités d’application dans de nombreux secteurs industriels (chimie, environnement, pharmacie...). Ainsi, ces travaux de recherche portent sur la synthèse et la caractérisation de matériaux composites submicroniques : il s’agit de silices colloïdales sur lesquelles sont greffés des silanes ou supportés des polysaccharides. Une des applications de ces travaux de recherche porte sur l’adsorption de métaux de transition sur ces composites en solution aqueuse. Dans le cadre de ce doctorat, les caractéristiques des composites sont définies par leur morphologie de surface, par l’étude des groupements fonctionnels présents, par détermination de leurs surfaces spécifiques ainsi qu’en solution aqueuse par détermination de leurs diamètres hydrodynamiques et de leurs potentiels zéta. Dans un premier temps, la fonctionnalisation de la silice a permis le greffage de groupements carboxyliques et amines dont tes taux de greffage obtenus ont été respectivement de 0,47 µmol/m² et 3,86 µmol/m². En présence de groupements amines, le potentiel  des composites est positif jusqu’ à pH 9 alors qu’il est négatif dès pH 3 pour des silices non fonctionnalisées. Dans un second temps, la silice est supportée par du chitosane dont le degré de désacétylation est de 77%. Conjointement, l’encapsulation de la silice est réalisées par du chitosane sur lequel des fonctions carboxyliques ont été greffées. La morphologie des particules est alors modifiée, leurs diamètres hydrodynamiques sont plus élevés et leurs potentiels  sont positifs jusqu’ à pH basique. La rétention d’ions métalliques (Cu(II) et Ni(II)) par ces composites à différents pH est ensuite étudiée. Pour chacun des cations métalliques, les capacités d’adsorption sont déterminées ainsi que les cinétiques d’adsorption. L’application de plusieurs modèles d’isotherme d’équilibre a été réalisée. Dans le cas de Cu(II), à pH 5, les meilleures capacités d’adsorption sont obtenues pour des silices supportées par du chitosane greffé : la capacité de rétention des ions Cu(II) est de 270 mg/g à pH 5. De même, c’est ce composite qui permet la meilleurs rétention des ions Ni(II) à pH 7 avec une capacité d’adsorption de 263 m/g. Concernant la cinétique, le modèle de réaction de surface du pseudo-second ordre s’applique bien aux résultats expérimentaux
This study is focused on the preparation of three types of silica-based composites for the capture of Cu(II) and Ni(II) ions. The first strategy consists in coating chitosan on colloidal fumed silica after acidic treatment yielding the composite SiO2+CS. The second strategy can be separated into two routes: the first one involves surface grafting of silica with aminopropyltriethoxysilane to obtaining silica particles covered by amino groups (SiO2(NH2)). The second one involves in surface condensation of triethoxysilylbutyronitrile, followed by acidic hydrolysis of the surface-bound nitrile groups affording silica particles covered by carboxyl groups (SiO2(CO2H)). In the last step, chitosan has been grafted on the surface bound NH2 or -CO2H groups yielding the composites SiO2(NH2)+CS or SiO2(CO2H)+CS. The third strategy involves in the modified CS surface with -CO2H groups, followed by coating onto the non-modified silica nanoparticles to obtain the composite SiO2+CS(CO2H). The novel hybrid materials were characterized by IR spectroscopy, scanning electron microscopy, atomic force microscopy, and zeta potential measurements. Batch experiments were conducted to study the sorption performance of these composites for Cu(II) and Ni(II) removal from aqueous solution at optimum pH at 298 K. The kinetics were evaluated utilizing pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The adsorption kinetics followed the mechanism of the pseudo-second-order equation for all types of adsorbents. The adsorption isotherms were evaluated utilizing Langmuir, Freundlich, and Temkin models. The best interpretation for equilibrium data was given by Langmuir isotherm model. This study demonstrates that the adsorption capacities for Cu(II) ion is more efficient for the SiO2+CS (256 mg g-1) compared to SiO2(NH2) (75 mg g-1). However, the carboxyl grafted CS-coated silica (SiO2+CS(CO2H) exhibited an excellent adsorption capacity (333 mg g-1). In case of Ni(II), based on Langmuir isotherm the maximum adsorption capacity found to be 182 mg g-1for SiO2+CS, and 210 mg g-1 for SiO2(CO2H) + CS. Using single-metal solutions, these adsorbents were found to have an affinity for metal ions in order as Cu(II) > Ni(II). The adsorption of Cu(II) ion by SiO2+CS was affected by the nature of the respective anion. Application of these composite materials to remove Cu(II) and Ni(II) from aqueous solution was shown to be more efficient than the adsorption capacities of many sorbents probed by other research groups

The research project has been focused on the preparation and characterization of Mg(b1-xCx)2 powder and bulk samples using chemical vapour coated boron and silica coated boron by sol-gel method. The chemical vapour deposition of carbon on boron powder was achieved by reacting ethylene gas on high purity nano-sized boron particles (20-100nm diameter) with varying deposition temperatures and partial pressures. Undoped and carbon doped boron was then reacted with magnesium rod to produce both Mg(b1-xCx)2 powder and bulk samples. Transmission electron microscopy showed that the chemical vapour deposition achieved a uniformly thick carbon-rich layer on each particle, regardless of particle size. In addition, the analusis of the diffraction peaks and the characterization of the magnetisation has evidenced the coexistence of phases with different levels of carbon resulting in multiple current paths within the Mg(B1-xCx)2 samples. The study of the preparation process for bulk Mg(B1-xCx)2 samples has evidenced that reducing the difference between the time constant of reaction and the time constant of diffusion is crucial to opbtain well-sintered samples devoid of cracks. Doping with carbon has shown significant improvements in the field dependence of K for the MG(B1-xCx)2 bulk samples reaching values comparable with the best literature-reported data for bulk samples. However, the K values of the MG(B1-xCx)2 bulk samples were observed to be noticeably lower when compared with the beszt liter4arture-reported data for wires and tapes, owing to the greater density achievable in the latter. In contrast to the carbon doping, the coating with silica via sol-gel process was found to impair the in-field Jc properties of Mg(B1-xCx)2 bulk samples, presumably due to the huge amount of silica loaded onto the boron powder and to the formation of carbonate and silicate impuritis within their reacted microstructure.

Sample preparation as an essential step in mass spectrometry-based analysis, plays a critical role in proteomics studies. Magnetic nanoparticles (MNPs) have been widely used in protein and peptide sample preparation due to their magnetic properties, biocompatibility, easy synthesis and surface functionalization. MNPs loaded with analyte or analyte modification reagent can be easily separated from the reaction medium by an externally applied magnetic field. The small size of MNPs provides high analyte loading and extraction capacity. Additionally, MNP can be decorated with different functional groups to achieve selective modification or extraction of analyte. In this study we have utilized silica coated iron oxide magnetic nanoparticles (Fe3O4@SiO2 MNPs) for protein and peptide sample preparation. Fluorescence-based methods were utilized for quantitative and qualitative characterization of N-hydrosucccinimidyl (NHS) ester groups on the surface of Fe3O4@SiO2 MNPs. Fluorophore Dansylcadaverine was conjugated to NHS ester functional groups. Fluorometric measurement of cleaved dansylcadaveine was employed to determine the number of NHS ester groups per MNPs that was found to be 2.6 × 102 and 3.4 × 103for 20 nm and 100 nm Fe3O4@SiO2 MNPrespectively. The efficiency of labeling native bovine serum albumin (BSA) by NHS ester coated Fe3O4@SiO2 MNPs was also explored in terms of maximizing the number of MNPs conjugated per BSA molecule or maximizing the number of BSA molecules conjugated per each MNP. Lysine residues of apolipoprotein B-100 (apoB-100) on the surface of intact human low density lipoprotein (LDL) were labeled by NHS ester modified Fe3O4@SiO2 MNPs in aqueous solvents at room temperature. The MNP labeledapoB-100 was treated by SDS to remove lipids and then digested using trypsin. Tryptic peptides were eluted from MNPs by cleaving disulfide linkage between labeled peptides and MNPs. LC-MS/MS analysis found 28 peptides containing labeled lysine residues. These lysine residues should be on the solvent exposed surface of LDL since the large size of MNPs prevents contact of the labeling reagent to those lysines embedded inside the structure of LDL. TCEP- immobilized Fe3O4@SiO2MNPs were fabricated and utilized for reduction of disulfide bonds in bovine pancreas insulin and two different cyclic peptides. Disulfide bonds were efficiently cleaved at room temperature in both organic and aqueous solvents confirmed by LC-MS/MS analysis of reduced/alkylated protein and peptides. Disulfide reduction and alkylation reactions was performed in one step and the reducing agent was simply separated from peptide and protein solution by magnetic separation.

Les travaux réalisés durant cette thèse ont eu pour but de développer les applications des nanomatériaux en biologie. Les films multicouches de polyélectrolytes s’assemblant par interactions électrostatiques ont ainsi pu être appliqués à l’isolement de cellules mammifères adhérentes. Les propriétés de ce type de film permettent de contrôler la diffusion de molécules jusqu’aux cellules et ouvrent de nouvelles perspectives pour l’encapsulation de cellules et ces applications. Les nanomatériaux utilisés ont également permis l’élaboration de capsules composites (liposome / polyélectrolytes réticulés) et (liposome / silice) présentant une stabilité accrue et un meilleur contrôle de leur perméabilité. En collaboration avec la société Nanobiotix, des nanoparticules magnétiques activables par un champ magnétique externe et dirigées spécifiquement contre les cellules tumorales ont été élaborées, développant ainsi les applications des nanotechnologies en thérapie anticancéreuse par voie physique
The aim of our studies was to translate nanomaterials progresses in biological applications. The assembly of polyelectrolytes by electrostatic interactions leads to the formation of multilayer films with tunable properties. Here we have applied this technique for polyelectrolytes multilayer formation onto the surface of adherent mammalian cells. Polyelectrolytes properties allow a better control of molecule diffusion across the film and give new outlooks for cells encapsulation and its applications. Nanomaterials were also used for the elaboration of two kinds of composite capsules: (liposome / reticulated polyelectrolytes) and (liposome / silica) capsules which present a better stability and allow a more efficient control of their permeability. In collaboration with the start-up Nanobiotix, magnetic nanoparticles activable by external magnetic field and specifically targeted against tumoral cells have been designed, leading to new development of nanotechnologies in physical anticancer therapies

У овој докторској дисертацији приказани су резултати синтеза и карактеризација нано-композитних честица са језгро-омотач структуром. Нанокомпозитне честице су синтетисане у течној фази, електростатичком депозицијом in situ синтетисаних SiO2, Fe3O4, ZnFe2O4 или NiFe2O4 наночестица на површину монодисперзних и сферичних силика језгро честица (средњег пречника ~ 0,4 μm). Силика језгро честице су синтетисане хидролизом и кондезацијом TEOS-a у базној средини. Силика наночестице су добијене неутрализацијом јако базног воденог раствора натријум силиката, док су феритне наночестице синтетисане копреципитацијом из воденог раствора одговарајућих нитратних соли. Да би се омогућила електростатичка депозиција нано-честица, силика језгра су функционализована са 3-аминопропилтриетоксисилан (APTES) или поли(диалилдиметиламонијум хлорид) (PDDA) чиме се повећава изоелектрична тачка силика честица. На овај начин су око силика језгро честица синтетисани једнослојни омотачи на бази SiO2, Fe3O4, ZnFe2O4 или NiFe2O4.Резултати су потврдили да се униформан силика слој може депоновати на функцијонализованим силика честицама. Формиран силика омотач је имао дебљину ~ 30 nm, мезопорозну структуру са средњом величином пора од ~ 8 nm и значајном укупном запремином пора. Због тога су тако добијене силика језгро-омотач наноструктуре погодне за имобилизацију ензима али и неких других активних материја. Такође је потврђено да је оптимална pH вредност за синтезу хомогеног Fe3O4 омотача на нефункционализованим силика језгрима ~ 5,4. Добијени Fe3O4 омотач је суперпа-рамагнетан са температуром блокирања ~ 25 К. Уградња никла и цинка у феритну структуру омотача није било могуће на нижим pH вредностима. Међутим, показано је и да је на вишим pH вредностима велика брзина формирања феритних честица и њихова самоагрегација доминира над конкурентном реакцијом депозиције феритних честица на функционализована силика језгра. У циљу спречавања самоагрегације, депо-зиција ZnFe2O4 и NiFe2O4 наночестица на PDDA-функционализованим силика језгрима је обављена у присуству цитратне киселине на pH > 7. Цитратна киселина пасивизира површину феритних наночестица и на тај начин инхибира самоагрегацију, омогућавајући депозицију ових честица на површину PDDA-функционализованих силика језгара.У овој тези су синтетисане честице са двослојним омотачем, који се састоје од унутрашњег Fe3O4 и спољашњег силика слоја. На PDDA-функцио-нализованим SiO2-језгро/Fe3O4-омотач честицама, обављена је депозиција силика наночестица чиме је формиран спољни мезопорозни силика омотач. Добијене су композитне честице са два различита функционална слоја: унутрашњим који омогућава магнетну сепарацију честице из реакционог медијума и спољним који омогућава имобили-зацију активних материја. Добијени резултати су указали да се ове нанокомпозитне честице могу употребити у биоинжењерству и областима хертерогене катализе.
U ovoj doktorskoj disertaciji prikazani su rezultati sinteza i karakterizacija nano-kompozitnih čestica sa jezgro-omotač strukturom. Nanokompozitne čestice su sintetisane u tečnoj fazi, elektrostatičkom depozicijom in situ sintetisanih SiO2, Fe3O4, ZnFe2O4 ili NiFe2O4 nanočestica na površinu monodisperznih i sferičnih silika jezgro čestica (srednjeg prečnika ~ 0,4 μm). Silika jezgro čestice su sintetisane hidrolizom i kondezacijom TEOS-a u baznoj sredini. Silika nanočestice su dobijene neutralizacijom jako baznog vodenog rastvora natrijum silikata, dok su feritne nanočestice sintetisane koprecipitacijom iz vodenog rastvora odgovarajućih nitratnih soli. Da bi se omogućila elektrostatička depozicija nano-čestica, silika jezgra su funkcionalizovana sa 3-aminopropiltrietoksisilan (APTES) ili poli(dialildimetilamonijum hlorid) (PDDA) čime se povećava izoelektrična tačka silika čestica. Na ovaj način su oko silika jezgro čestica sintetisani jednoslojni omotači na bazi SiO2, Fe3O4, ZnFe2O4 ili NiFe2O4.Rezultati su potvrdili da se uniforman silika sloj može deponovati na funkcijonalizovanim silika česticama. Formiran silika omotač je imao debljinu ~ 30 nm, mezoporoznu strukturu sa srednjom veličinom pora od ~ 8 nm i značajnom ukupnom zapreminom pora. Zbog toga su tako dobijene silika jezgro-omotač nanostrukture pogodne za imobilizaciju enzima ali i nekih drugih aktivnih materija. Takođe je potvrđeno da je optimalna pH vrednost za sintezu homogenog Fe3O4 omotača na nefunkcionalizovanim silika jezgrima ~ 5,4. Dobijeni Fe3O4 omotač je superpa-ramagnetan sa temperaturom blokiranja ~ 25 K. Ugradnja nikla i cinka u feritnu strukturu omotača nije bilo moguće na nižim pH vrednostima. Međutim, pokazano je i da je na višim pH vrednostima velika brzina formiranja feritnih čestica i njihova samoagregacija dominira nad konkurentnom reakcijom depozicije feritnih čestica na funkcionalizovana silika jezgra. U cilju sprečavanja samoagregacije, depo-zicija ZnFe2O4 i NiFe2O4 nanočestica na PDDA-funkcionalizovanim silika jezgrima je obavljena u prisustvu citratne kiseline na pH > 7. Citratna kiselina pasivizira površinu feritnih nanočestica i na taj način inhibira samoagregaciju, omogućavajući depoziciju ovih čestica na površinu PDDA-funkcionalizovanih silika jezgara.U ovoj tezi su sintetisane čestice sa dvoslojnim omotačem, koji se sastoje od unutrašnjeg Fe3O4 i spoljašnjeg silika sloja. Na PDDA-funkcio-nalizovanim SiO2-jezgro/Fe3O4-omotač česticama, obavljena je depozicija silika nanočestica čime je formiran spoljni mezoporozni silika omotač. Dobijene su kompozitne čestice sa dva različita funkcionalna sloja: unutrašnjim koji omogućava magnetnu separaciju čestice iz reakcionog medijuma i spoljnim koji omogućava imobili-zaciju aktivnih materija. Dobijeni rezultati su ukazali da se ove nanokompozitne čestice mogu upotrebiti u bioinženjerstvu i oblastima herterogene katalize.
This thesis presents the results of the synthesis and characterization of the nanocomposite particles with core-shell structure. Nanocomposite particles were synthesized by liquid-phase technique through electrostatic deposition of in situ synthesized SiO2, Fe3O4, ZnFe2O4 or NiFe2O4 nanoparticles on the surface of spherical and monodispersed silica core particles (average size ~ 0.4 μm). Silica core particles were prepared by hydrolysis and condensation of tetraethylorthosilicate in basic conditions. Silica nanoparticles were obtained by neutralization of highly basic sodium silicate solution while ferrite nanoparticles were obtained by coprecipitation from solutions of the corresponding nitrate salts. To improve electrostatic assembling of nanoparticles on the surface of silica core particles, the latter were functionalized with 3-amino-propyltriethoxysilane (APTES) or poly(diallyldimethylammonium chloride) (PDDA) which increases the isoelectric point of the silica core particles. In this way SiO2, Fe3O4 , ZnFe2O4 or NiFe2O4 shells were synthesized around the silica core particles, respectively.The results confirmed that uniform silica layer can be deposited at the functionalized silica core particles. The formed silica layer had thickness of ~ 30 nm, mesoporous structure with average pore size of ~ 8 nm and high total pore volume. This makes silica shell suitable for immobilization of enzymes. Optimal conditions for synthesis of homogenous and thin Fe3O4 shell around non-functionalized silica core particles were found at pH ~ 5.4. Obtained Fe3O4 shell was superparamagnetic with blocking temperature at ~25 К. Incorporation of nickel and zinc into ferrite structure was impossible at lower pH values. However at higher pH the formation rate of Ni- and Zn-ferrite particles becomes very fast and the self-aggregation dominates the competing formation of the ferrite shell around functionalized silica cores. Because of that the self-aggregation was prevented by surface modify-cation of ZnFe2O4 and NiFe2O4 nanoparticles with citric acid before their deposition on the PDDA-functionalized silica core and homogenous and continuous shells were finally obtained at pH > 7.In addition, bilayered shell composed of internal Fe3O4 layer and external SiO2 layer, were also prepared. Silica nanoparticles were deposited on the surface of PDDA-functionalized SiO2-core/Fe3O4-shell particles which induced formation of external mesoporous silica shell. Obtained composite particles had two different functional layers: internal which would allow its magnetic separation from reaction mixture and external which could allow imobilization of various molecules and nanoparticles such as enzymes inside its pores. Based on these results, obtained nanoparticles could be used in bioengineering and heterogenous catalysis.

A cinza obtida da queima controlada da casca de arroz é um material que apresenta propriedades pozzolânicas: reage na presença de água e dióxido de cálcio produzindo silicato de cálcio hidratado (C-S-H), o material que confere a resistência mecânica aos cimentos. Portanto, a cinza de casca de arroz é um material de potencial interesse para o desenvolvimento de cimentos não convencionais, baseados em subprodutos industriais ou agrícolas. Neste trabalho, os compostos presentes em cinzas de alta reatividade pozzolânica e os produtos obtidos de sua reação pozzolânica foram estudados através da Ressonância Magnética Nuclear (RMN) de alta resolução de 13C e 29Si. Na cinza não hidratada foram detectados domínios de sílica amorfa, o componente principal, e quantidades menores de sílica cristalina (cristobalita e quartzo), carbono amorfo e cadeias de siloxanos. Foi estudada a evolução da reação em pastas obtidas da hidratação da cinza na proporção água: cal: cinza O,47H20+O,53(O,1CCA+O,9Cal)=1 (entre 8 e 134 dias de idade). Mediante a RMN de 29Si foi possível caracterizar a formação de C-S-H e disposição dos grupos silicatos na estrutura. A estrutura do C-S-H obtido é comparável à observada em cimentos convencionais e cimentos de escoria de alto forno, e é compatível com os modelos propostos. A quantidade de C-S-H produzido e a velocidade da reação são menores quando comparadas com os outros cimentos. Efeitos da carbonatação de C-S-H foram observáveis em atmosfera ambiente. Foi detectado também o efeito da hidratação sobre os componentes minoritários da cinza.
The ashes obtained from burning rice husks have pozzolanic properties: in the presence of water and calcium dioxide the ashes react to produce calcium silicate hydrate (C-SH), the main binding agent in cementitiuos materials. Therefore, rice husk ashes are interesting materials in order to produce non-conventional cement, based in industrial or agricultural byproducts. The compounds present in a sample of rice husk ashes of high pozzolanic activity, and the products of hydration, were characterized using high resolution solid-state Nuclear Magnetic Resonance (NMR) of 13C and 29Si. Several compounds were detected in anhydrous ashes: amorphous silica (the main component), and minor quantities of crystalline silica (cristobalite and quartz), amorphous carbon and siloxane polymeric chains. Hardened pastes were prepared with a ratio water:calcium dioxide:ash O,47H20+O,53(O,1dioxide ash+O,9calcio)=1. The evolution of the hydration reaction was monitored at several ages between 8 to 134 days. The formation of C-S-H was detected by 29Si-NMR and the arrangement of the silicate groups was characterized. The structure of the C-S-H formed in these pastes agrees with the one observed in conventional cements and also b1ast furnace slag cements. Also, it is in agreement with the accepted structural models of C-S-H. The amount of C-S-H produced and the velocity of the reaction are minor than those observed in blast furnace slag cements. Carbonation effects were detected in ambient atmospheric conditions. Also, the effect of the hydration on the minority compounds was also detected.

碩士
國立成功大學
機械工程學系碩博士班
91
The research is focused on the preparation and characterization of physically or chemically surface-modified magnetite (Fe3O4) nanoparticleswhich are expected with the benefit of a easy fabrication of functionalities, and in turn with multi-applications in many areas. Fulfilling the above goal, a strategy has developed on coating a layer of silica onto the magnetite nanopatricles, which are stabilize by the surface charge repulsion from the coated silica, and functionalities are introduced by the wildly available silane coupling agents. There are three portions of the whole process: the coprecipitation of magnetite nanoparticle involving the chemical coprecipitation of Fe(II) and Fe(III) salts with ammonia hydroxide(NH4OH); the bilayered surfactant water-based magnetic fluid with oleic acid as surfactants, and the sol-gel nanocoating of silica. The silica-coated magnetite nanoparticles are characterized by X-ray diffraction, thermogravimetry analysis, dynamic light scating and electron microscopy.

碩士
正修科技大學
化工與材料工程研究所
99
The study of Acrylic coated silica core-shell nano particles.MMA acrylic monomer silica-polymer core-shell nanoparticlwere prepared by emulsion polymerization. By changing the parameters: MMA content, silica content, silica type, emulsifier content, H2O content, join MA monomer and ISO monomer to copolymerization. Analysis nano particle size and particle surface with nano-particle size analyzer and TEM transmission electron microscopy, analysis thermal stability nanocomposites with TMA DSC TGA, analysis special peaks with FT-IR. Theresearch done out of core - shell nanocomposite particles, but also filled with water inside of acrylic paint, acrylic paint to see if it can increase the mechanical strength and whether the impact of transparency. In this study, silica and sodium silicate were TEOS silica gel for the two silicone research, analysis TEOS silica and sodium silicate silicone in the same way, whether we can successfully synthesized, and analyzed the difference between.

碩士
逢甲大學
紡織工程所
96
The research prepared nano silica particles by Sol-gel method, and used APS(3-Aminopropyltriethoxysilane) to modify the surface of silica particles. The organic dyes of fluoresce was covalently attached to the surface of the inorganic silica and formed the fluoresce silica particles. In order to enhance the fluoresce strength performance, we prepared nano silica particles by different preparation conditions: the amounts of Tetraethyl Orthosilicate (TEOS), the concentration of ammonia et al.. The average particle diameter of nano silica particles was 120 nm from Submicron Particle Size Analyzer. In contrast, the Scanning Electron Microscope(SEM) pictures showed that they were around 100 nm in size. Firstly, we discussed the morphology of modified the silica particles by APS and subsequently adhered to the modified-silica by using FITC dye. The experimental result showed the optimal preparation conditions conditions for fluoresce strength performance were: the amount of APS(70%) was 20 μL, the amount of FITC( 5 mg/15 mL) was 5000 μL and the reaction time was 2 hours at 35℃ under stirring continuously by ultrasonic. Then, we analyzed the characteristic of the fluoresce silica particles with Submicron Particle Size Analyzer, Fluorescence microscope, Scanning Electron Microscope(SEM) and Energy Dispersive Spectrometer(EDS) et al..

碩士
國立高雄應用科技大學
化學工程與材料工程系
99
The dual functional particles with luminescent and magnetic properties are of particular importance because of their broad range of potential applications, e.g., biochemical sensing, biological imaging and cell tracking. Typically, the dual functional particles were prepared by incorporating emission centers, such as organic fluorophores, lanthanides or quantum dots. However, the preparation involved multiple processing steps and the incorporated luminescent materials are expensive and environmentally toxic. In view of this, a novel luminescent magnetic silica particle without incorporating fluorophores was developed in this study. Since the calcinated organosilica synthesized by mixing tetraethyl orthosilicate (TEOS) and 3-aminopropyl triethoxysilane (APTES) is able to emit fluorescence after calcinating at 600C, the magnetic core of Fe3O4 nanoparticles were coated with the organosilica as an emission layer. The results showed that the direct attachment of the fluorophore-free emission layer on Fe3O4 core would quench the fluorescence of the organosilica, indicating that an insulating layer between Fe3O4 core and emission shell was necessary. Accordingly, the luminescent magnetic particles were fabricated by first coating a silica layer on Fe3O4 nanoparticles, following by covering the fluorophore-free emission layer. The fluorescent intensity of the particles was affected by the thickness of the insulation silica layer as well as the preparation condition of the organosilica. An optimum thickness of insulated silica could prevent the quench by magnetic cores. The optimum condition for prepare the emission layer was employing TEOS and APTES at the molar ratio of 1:1 and calcining at 600C for 2 h. From XPS and TGA analysis, the mechanism for the emission of calcinated organosilica is though due to the defect centers in the silica forming by the impurities of carbon and oxygen rather than nitrogen centered effects. Since the quantum yield of the as-synthesized particles could be up to 0.25, the novel luminescent magnetic material free of fluorophore is expected to be promising for biosensing applications.

碩士
國立成功大學
材料科學及工程學系碩博士班
95
In this research, nonionic surfactant was used as liquid template and Na2SiO4 as SiO2 precursor to synthesis mesoporous silica SBA-15 with high specific surface area. The synthesized SBA-15 has surface area of 600 m2/g which could be served as the TiO2 supporter to reduce the TiO2 grain size and well-dispersed TiO2 for enhancing photocatalytic activity. In order to slow down the hydrolysis rate of TTIP(Titanium tetraisopropoxide) that used as precursor of TiO2, acetic acid was applied as a chelating agent to chelate with TTIP. The synthesized Titania/Silica composites were characterized by X-ray diffraction, FTIR, TEM, UV-Visible spectroscopy , etc. TEM micrographs showed that the organic solute template method could prepare the titania-silica composite, and successfully embedded titaina in SBA-15 channel. The mesoporous structure restrained the titania grain size within 5 nm which caused blue shift identified by UV-Vis spectra. This is due to the formation of Si-O-Ti bonding which was identified by FTIR. The dispersion effect promoted by the support prevents in all cases the anatase to rutile phase transformation observed in monolithic TiO2 materials upon identical calcination temperature. The order of the support framework still maintained upon loading different TiO2 content confirm by N2 adsorption/desorption and SAXS. The synthesized samples have shown their activity as photocatalysts for not only Methylene Blue(MB) solution but also MB dry powder.

碩士
逢甲大學
紡織工程所
97
It is well known that the ceramics matrix has an excellently mechanical property. The enhancements of the ceramic matrix with antibacterial effect by adding nano silver were studied. In this study, we used the silver as core layer matrix and the silica as shell layer to prepare Ag-SiO2 core-shell nanoparticles with highly thermal stability. This thesis consists of three parts: in the first part, we discussed nano silver particles used polyol process. In the IPA solution we used silver nitrate, PVP, and glucose solution as precursor salt, protection agent, and reducing agent, respectively. Then, we analyzed the characteristic of the silver particles with Submicron Particle Size Analyzer and UV-visible spectroscopy. The second part of this thesis is prepared Ag-SiO2 core-shell nanoparticles by Sol-gel method; added 0.5 ml TEOS and 1ml ammonia to the above-mentioned nano silver to carry out the silica growth reaction. Then we explored the characteristic and antibacterial effect of the core-shell particles by Submicron Particle Size Analyzer, UV-visible spectroscopy and antibacterial test. The third part of this thesis is proceeded different thermal treatment of the Ag-SiO2 core-shell particles, then we analyzed the particles shape and antibacterial effect by Scanning Electron Microscope(SEM) and antibacterial test. In this study showed the core-shell particles became densification after thermal treatment that induced silver ionic hard to release; therefore we added 50 ppm calcium ionic with synergetic contribution to release the silver ionic in the follow up experiment that enabled the Ag-SiO2 core-shell particles of two silica layers to each thermal stability of 1000℃ with antibacterial effect. In the end, we proved the formation of Ag-SiO2 core-shell particles by Energy Dispersive Spectrometer(EDS) and Transmission Electron Microscope(TEM).

碩士
國立高雄應用科技大學
化學工程與材料工程系碩士在職專班
105
The objectives of this research are the preparation and characterization of mesoporous silica coated multi-wall carbon nanotubes/silica particles/epoxy nanocomposites for application to the semiconductor encapsulant materials, especially the underfill materials for flip chip packaging application. A simple synthetic method for placing a mesoporous silica coating on multi-wall carbon nanotubes was developed to improve the surface compatibility with regard to a SiO2 filled epoxy resin. The silanol groups on the surface of silica particles and mesoporous silica shell of CNTs provides a platform to attach silane molecules (e.g. 3-glycidoxy propyltrimethoxysilane, GPTMS) that enable higher compatiblility and interaction with epoxy matrix. The effect of 3-glycidoxypropyltrimethoxysilane (GPTMS) functionalization and mesoporous silica coated carbon nanotubes (CNTs@MS) enrichment of silica particles (SiO2) on thermal and mechanical properties of epoxy based composite materials were investigated. In particular, CNTs@MS and SiO2 act synergistically to enhance the performance both on the thermal and mechanical properties of epoxy composites. The viscosities of epoxy composites were characterized by rheometer. The morphology of fracture surface of the epoxy composites were observed by scanning electron microscope (SEM). The thermal and mechanical properties of the epoxy composites were characterized using dynamic mechanical analysis (DMA), thermo-mechanical analysis (TMA) and thermal conductivity measurement. The results showed that the loading amount of the fillers have to be controlled in the percentage of 50 wt.% SiO2 and 10 wt.% CNTs@MS in order to meet the requirement of viscosities for underfill materials application. Moreover, the storage modulus, glass transition temperature (Tg) and thermal conductivity increased along with the amount of silane functionalized CNTs@MS, and the coefficient of thermal expansion decreased gradually.

碩士
國立中央大學
機械工程學系
107
In this paper, we use solvent supersaturation method in atmosphere to synthesize a fully inorganic perovskite quantum dot with high luminosity; and use APTES as a ligand to replace the organic long chain molecule. By replacing the ligand, we can prevent organic long chain molecules remain on the surface of device and can improve the characteristics of the device. Due to using APTES as ligand to synthesize perovskite quantum dots, we can coat silica on the surface of quantum dot as protection layer by utilize the characteristics of APTES. The protective layer can effectively prevent the quantum dots from being affected by environmental issues. In this study, we tried to find the best PLQY by trying different Pb and APTES molar ratios. We found that when the Pb and APTES molar ratio is 1:1.5, there will have the best result of PLQY 58%. In addition, by utilizing the characteristics of organic silane, we can combine quantum dot and silica nanospheres together. The silica-coated perovskite quantum dots can attach to the surface of nanospheres. Due to the optical properties of the nanospheres, we can cause UV-light scattered and increase the opportunity for quantum dots on the sphere surface to absorb photons. We add different weights of nanospheres into the solvent which contain quantum dots to find the best result. When quantum dots and nano sphere have weight ratio at 1:2.17 can form diffractive particles(DP) with high PLQY 81%. Greatly improve the luminous efficiency of quantum dots. The self-synthesized diffractive particles can be combined with polymethyl methacrylate(PMMA) to make perovskite quantum dots diffusion film. The film made by this method may be a potential candidate of next generation color filter.

碩士
國立高雄應用科技大學
模具工程系碩士班
102
In this paper, the magnetic nanoparticles of Fe3O4 were prepared with a chemical co-precipitation method. The Fe3+ and Fe2+ solution was mixed with NH4OH by heating and stirring and using N2 to protect the reaction, after that the Fe3O4 magnetic nanoparticles were obtained. Next, the core-shell structures of SiO2 coated with Fe3O4 nanocomposite particles were prepared by sol-gel method, in which the hydrolysis of TEOS was conducted on the surface of Fe3O4 with the aid of basic catalyst at room temperature. In this study, the surface shape and component of Fe3O4 nanoparticles and Fe3O4 coated SiO2 nanocomposite particles were studied by ESEM, EDS and TEM. The crystal structure was studied by use of XRD. The magnetic nano-particles size before and after the modification with TEOS were studied with TEM. The results indicated that the magnetic nanoparticles were aggregate due to the particles attraction each other, and the magnetic nanoparticles had very small size. The average particles size of addition 5 ml ammonia solution were 10.303 nm and addition 20 ml ammonia solution was 8.86 nm. The results indicate that the Fe3O4 magnetic nano-particles size is smaller with addition of 20 ml ammonia solution. After Fe3O4 coated with SiO2 were observed by use of TEM, it was confirmed that the SiO2 were successfully coated on the surface of Fe3O4 magnetic nanopraticles.

碩士
國立高雄應用科技大學
化學工程與材料工程系博碩士班
102
Polyethyleneimine (PEI) coated material can be used in bioseparation, wastewater treatment, removal of heavy metals, and DNA delivery. In general, PEI modified magnetic materials were obtained by covalently grafting PEI on magnetic silica composites as well as directly coating or covalently binding PEI on Fe3O4 nanoparticles. In order to prepare uniform-sized and monodispersed PEI-coated magnetic silica (Fe3O4@SiO2@PEI) nanoparticles, a novel one-pot reverse micelle method was proposed in this work. First, the Fe3O4 nanoparticles and tetraethyl orthosilicate (TEOS) were dispersed sequentially in the water-in-oil droplets of the reverse micelle system. Then, PEI was introduced in the same water-in-oil droplets suspension to cover the as-synthesized Fe3O4@SiO2 particles. The resultant PEI-coated magnetic silica nanoparticles (Fe3O4@SiO2@PEI) with a mean diameter of 50 nm were characterized by transmission electronic microscopy (TEM), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), zeta potential analyzer, and superconducting quantum interference device vibrating sample magnetometer (SQUID VSM). The as-prepared Fe3O4@SiO2@PEI was applied to adsorb methyl orange for examining their applicability on bioseparation process. Our results showed that the adsorption of methyl orange by the Fe3O4@SiO2@PEI follow Langmuir isotherm. At 25C, the optimum pH level for methyl orange adsorption was pH 4, which should be correlated to the electric charge of methyl orange and the surface electric potential of the Fe3O4@SiO2@PEI. Since the pKa of methyl orange is 3.1, the charge of methyl orange is negative above pH 3.1. Additionally, the zeta potential of the Fe3O4@SiO2@PEI is highest at pH 4 and then decrease with the increase in pH during the pH range from 4 to 10. The results imply that the adsorption mechanism of methyl orange by the Fe3O4@SiO2@PEI nanoparticles is governed by electrostatic interaction. The adsorbed methyl orange could be desorbed by 0.1 M NaOH. The regenerated Fe3O4@SiO2@PEI nanoparticles were able to apply to next adsorption process and the adsorption capacity could maintain above 90% after three adsorption/desorption cycle. The PEI-coated magnetic silica nanoparticle synthesized in this study is a promising adsorbent for adsorption and separation processes because of their short adsorption equilibrium time, high adsorption capacity and good regenerative ability.

碩士
國立高雄應用科技大學
化學工程與材料工程系博碩士班
103
Layered double hydroxide (LDH) is a layered structure material consisting of divalent and trivalent metal hydroxides, wherein the anion compounds and water are replaceable. As a result, LDH can function like an anion exchanger. The LDH composite integrated with magnetic component could be recovered by magnet and used in establishing a separation process without centrifugation and filtration. A simple route for preparing a magnetic LDH with high adsorption capacity is still a challenge work. Accordingly, this article proposed a two-stage synthetic method for preparing a high adsorption capacity magnetic LDH material. First, the magnetic silica cores (Fe3O4@SiO2) were covered with aluminum isopropoxide to form the aluminum hydroxide (AlOOH) layer which was severed as the seed layer for LDH growth. Then, the LDH shell was fabricated by co-precipitation reaction of zinc nitrate, magnesium nitrate, and urea. The resultant core-shell magnetic LDH composite (Fe3O4@SiO2@ZnMgAl-LDH) was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and the surface area and pore size analyzer (BET). TEM images showed the radius of the magnetic core (Fe3O4@SiO2) was 60 nm, the LDH sheet was 50-150 nm long and 1-2 nm wide. The as-prepared magnetic LDH was mesoporous with a pore diameter of 6.5 nm and a specific surface area of 360 m2/g material. Methyl orange (isoelectric point (pI) = 3.1) was employed as the adsorbate for investigating the adsorption properties of the Fe3O4@SiO2@ZnMgAl-LDH. The adsorption capacity decreases as the increase in temperature. In addition, the highest adsorption capacity was in the range of pH 5-6 and reached to the level of 2800 mg/g adsorbent at 25°C, implying that the adsorption behavior was governed by the electrostatic interaction. The adsorption behavior of Fe3O4@SiO2@ZnMgAl-LDH could be well fitted with Dubinin-Radushkevich model, indicating that the adsorption ability among various adsorption sites were different. The time course adsorption study demonstrated that the adsorption of methyl orange by Fe3O4@SiO2@ZnMgAl-LDH approached pseudo-second kinetics; therefore, chemical adsorption may dominate the whole adsorption process. Additionally, the whole adsorption process may involve three stages: exterior diffusion, interior diffusion and equilibrium stage. The seed layer-coprecipitation method proposed in this article can fabricate high adsorption capacity magnetic LDH composite and develop novel the magnetic adsorbents with high adsorption ability.

碩士
國立雲林科技大學
環境與安全衛生工程系碩士班
101
As booming development of semiconductor industry, wastewater produced containing substantial quantities of fine abrasive particles is considerable. In recent years, magnetic particles aggregation in wastewater treatment is applied gradually, using the magnetic field to attract deposition after the absorption of magnetic particles. The results show that the best effect of polyaluminum chloride (PAC) coagulant is at pH = 6, and doses up to 0.08 g L-1 .Because of the smaller particle size of magnetic particles have a large adsorption surface area relatively at pH=4, and opposite electric charge of zeta potential between silica and magnetic particles. It has better effect owing to the attraction of opposite magnetic poles. The best effect of magnetic particles is at pH = 4, and doses up to 3.74 g L-1. When magnetic particles are not enough, whole electrical poles of particle group after adsorption are still negative owing to the silica. Magnetic particles and silica float around the mixed liquid because the repulsion. When magnetic particles are too much, whole electrical poles of particle group after adsorption become positive electrode owing to the magnetic particles. Only in the appropriate dosage, magnetic particles and silica have charge neutralization. At this moment, it has the best effect because of the electrical poles of particle group are so weak even zero that it can aggregate each other by slow stir or the Brownian movement. Using PAC coagulant with magnetic particles treat the wastewater has the better effect than each does things in its own way. In 1000 mL wastewater, the dosage of PAC coagulant can be reduced one half when added to magnetic particles 2.49 g L-1; It can be reduced 75% when magnetic particles doses up to 3.74 g L-1.

碩士
國立成功大學
生物科技研究所碩博士班
92
In our study, we synthesized magnetic nano-particles coated with an anti-cancer medicine doxorubicin to form three new-types magnetic nano anti-cancer medicine. By magnetic leading, the magnetic nano-particles can be targeted to the tumor site for therapy. The advantages are increasing drug concentration at the tumor and lowering drug concentration in the other region of body to avoid the significant side effect of chemical drugs. Our purpose is examining the in vivo and in vitro activity of this new-type anti-cancer medicine. In vitro activity experiment was performed on murine bladder tumor cell (MBT-2) and the survival cell was quantitated by MTT assay. The activity of magnetic nano-particles coated with doxorubicin were compared to free magnetic nano-particles and free doxorubicin. We found that magnetic nano-particle coated with doxorubicin exhibits activity similar to free doxorubicin but the magnetic nano-particle alone dosen’t show any activity. Besides, when we provide a external magnetic field to target the magnetic nano-particles and we found that magnetic nano-particles coated with doxorubicin can be targeted and killed the cancer cell. But there are no observable toxicity in the same test on normal cell line COS-7. In In vivo experiment, we first induced tumor formation in mice, and then implanted a small magnetic in tumor. Then we injected magnetic nano-particles with doxorubicin into the tumor. We found that magnetic nano-particles coated with doxorubicin can be target to the tumor site and kill the tumor cells.

碩士
國立交通大學
應用化學系所
97
The thesis is divided into two parts, part 1 and part 2. Part I of the thesis describes the design and synthesis of bis(mannoside) ligands with mono- and tri-valent anchor, and the binding of these synthetic carbohydrate ligands on alumina-coated magnetic nanoparticles through non-covalent interactions. Three different chemical functions were chosen as non-covalent anchors, namely phosphate, sulfate and carboxylate functionalities; for comparison purpose, a mono-hydroxyl and trihydroxyl anchor were also made to serve as experiment control samples for binding studies. The design of bis(mannoside) ligands with mono- and tri-valent anchor is dissected into four portions: (1) Derivatives contain bis(mannoside) ligands, which provide binding function for specific protein receptors; (2) a molecular spacer is inserted between bis(mannoside) ligand derivative and non-covalent anchor; (3) a selected chemical functionality is installed at the terminus, which presumably would bind to the alumina surface of magnetic nano-particles; and (4) alumina-coated magnetic nanoparticles provide binding template for carbohydrate ligands with functionalized anchors. In subsequent binding study, it was found that binding of ligands with phosphate functions follow the Langmuir adsorption model, while binding properties of other non-covalent anchors is less conclusive. The dissociation constants (kd) of monophosphate and triphosphate anchors are 1.15 × 10-6 M-1 and 1.69 × 10-6 M-1 respectively. Part 2 of this thesis is based on the findings in part 1 and explored their application. Thus different monophosphate bis(carbohydrate) ligand derivatives were prepared and successfully anchored to the surface of alumina coated magnetic nano-particles. In this study, bis(D-galactose), bis(D-mannose) and bis(L-fucose) ligand were used. To construct a small combinatorial libraries, we prepared the carbohydrate grafted nanoparticles with one type of bis(carbohydrate) ligands (�e 3), two types of bis(carbohydrate) ligands (�e 3) and all three types of bis(carbohydrate) ligands. With this small library in hand, binding studies of carbohydrate ligand coated nanoparticles to pathogenic E.coli bacteria are underway and results will be published in due course.

No
Cd3P2 quantum dots (QDs) have been synthesized in both aqueous and high boiling point surfactant solutions via a gas-bubbling method. The synthesized QDs exhibit photoluminescent wavelengths spanning across the visible red to the near-infrared (NIR) spectral region. Two types of shell materials, SiO2 nanobeads and PS micro-spheres, have been employed to encapsulate the Cd3P2 QDs which provide protecting layers against physiological solutions. The coating layers are proven to enhance the optical and chemical stability of Cd3P2 QDs, and make the fluorescent particles capable of sustaining long-term photo-oxidation. To demonstrate the applicability of the bio-labelling, the fluorescent composite particles (PS@QDs, SiO2@QDs) were injected into a culture medium of colorectal carcinoma (LoVo) cells. The results demonstrated that the PS@QDs exhibited a brighter fluorescence, but the SiO2@QDs provided a better photostability which consequently led to long-term cancer cell detection as well as a much lower release of toxic Cd2+ into the PBS solutions.