Journal articles: 'Crosslinking (edc/nhs)'

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Liu, Rong, Feng Zhang, Bao Qi Zuo, and Huan Xiang Zhang. "EDC-Crosslinked Electrospun Silk-Fibroin Fiber Mats." Advanced Materials Research 175-176 (January 2011): 170–75. http://dx.doi.org/10.4028/www.scientific.net/amr.175-176.170.

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Electrospun Silk-Fibroin (SF) mats were fabricated by electrospinning with regenerated Bombyx mori silk-fibroin/formic acid solutions. After spinning, the water soluble and mechanical properties of pure fibroin nanofibers were poor. So electrospun SF mats were crosslinked with N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC), a low cell cytotoxicity crosslinking agent, and N-hydroxysuccinimide (NHS), which can increase the reaction rate. The scanning electron microscope images indicated that the diameter of fibers increased with crosslinking reaction. When EDC/NHS reached to 7.5wt.%, the diameter of fibers achieved the maximum. The mechanical test showed that tensile strength enhanced after crosslinking with EDC/ NHS. While EDC/NHS reached to 7.5wt %, the rupture strength reached to (38.31±5.30) Mpa, and the breaking elongation ratio reached to (182.00±31.27) %. FTIR results showed the the proportion of β-sheet increased while random coil and α-helix decreased after treatment.

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Siridamrong, Pornpen, Penchom Phrotjanatharee, and Niyom Thamronganaskul. "Chemical Crosslinking of Silk Fibroin, Chitosan and Gelatin Blend Nanofiber Mats." Key Engineering Materials 695 (May 2016): 273–77. http://dx.doi.org/10.4028/www.scientific.net/kem.695.273.

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Silk fibroin (SF), chitosan (C), and gelatin (G) blend composition in formic acid have been manufactured by using electrospinning technique in our previous work. The SF: G: C at weight ratios of 10: 20: 1 and 20: 10: 1 (%wt: %wt: ml) were used for crosslinking testing. Glutaraldehyde (GA), and 1-ethyl-3-(3-dimethylaminopropyl) cabodiimide (EDC) / N-hydroxy succcinimide (NHS) (EDC/NHS) were chose as crosslinking agents. All samples were treated in such agents by fumigation for 72 hours followed by dipping for 10 minutes. Then those samples were washed in distill water for 3 times (1 time per 10 minutes) and dried in desiccator at room temperature. GA caused immediately shrink in both nanofiber mats and became clearly visible yellowish. However, a little shrinkage occurred after dipping in EDC/NHS. It possibly concluded that the EDC / NHS appropriated for SF: G: C blend nanofiber mats.

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Yang, Xingxing, Xiaoyun Wang, Fan Yu, Linlin Ma, Xiaohan Pan, Gejie Luo, Si Lin, Xiumei Mo, Chuanglong He, and Hongsheng Wang. "Hyaluronic acid/EDC/NHS-crosslinked green electrospun silk fibroin nanofibrous scaffolds for tissue engineering." RSC Advances 6, no. 102 (2016): 99720–28. http://dx.doi.org/10.1039/c6ra13713j.

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Nair, Malavika, Yonatan Calahorra, Sohini Kar-Narayan, Serena M. Best, and Ruth E. Cameron. "Self-assembly of collagen bundles and enhanced piezoelectricity induced by chemical crosslinking." Nanoscale 11, no. 32 (2019): 15120–30. http://dx.doi.org/10.1039/c9nr04750f.

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The choice of crosslinking is shown to enhance the piezoelectric response of a collagen construct. In particular, EDC-NHS crosslinking induces the self-assembly of collagen bundles which present a localised piezoelectric response.

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Dulnik, Judyta, and Paweł Sajkiewicz. "Crosslinking of Gelatin in Bicomponent Electrospun Fibers." Materials 14, no. 12 (June 18, 2021): 3391. http://dx.doi.org/10.3390/ma14123391.

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Four chemical crosslinking methods were used in order to prevent gelatin leaching in an aqueous environment, from bicomponent polycaprolactone/gelatin (PCL/Gt) nanofibers electrospun from an alternative solvent system. A range of different concentrations and reaction times were employed to compare genipin, 1-(3-dimethylaminopropyl)-N’-ethylcarbodimide hydrochloride/N-hydroxysuccinimide (EDC/NHS), 1,4-butanediol diglycidyl ether (BDDGE), and transglutaminase. The objective was to optimize and find the most effective method in terms of reaction time and solution concentration, that at the same time provides satisfactory gelatin crosslinking degree and ensures good morphology of the fibers, even after 24 h in aqueous medium in 37 °C. The series of experiments demonstrated that, out of the four compared crosslinking methods, EDC/NHS was able to yield satisfactory results with the lowest concentrations and the shortest reaction times.

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YANG, CHUNRONG. "Enhanced physicochemical properties of collagen by using EDC/NHS-crosslinking." Bulletin of Materials Science 35, no. 5 (October 2012): 913–18. http://dx.doi.org/10.1007/s12034-012-0376-5.

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Liu, Sa, Minglei Chu, Yongjun Zhu, Lifeng Li, Lin Wang, Huichang Gao, and Li Ren. "A novel antibacterial cellulose based biomaterial for hernia mesh applications." RSC Advances 7, no. 19 (2017): 11601–7. http://dx.doi.org/10.1039/c6ra26216c.

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A novel bacterial cellulose/collagen–hydroxypropyltrimethyl ammonium chloride chitosan composite (BCC–H), as an ideal artificial hernia mesh, was synthesized by combining solution impregnation with the EDC/NHS chemical crosslinking method .

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Kempin, Wiebke, Anna Baden, Werner Weitschies, and Anne Seidlitz. "Glycerol gelatin for 3D-printing of implants using a paste extrusion technique." Current Directions in Biomedical Engineering 3, no. 2 (September 7, 2017): 389–92. http://dx.doi.org/10.1515/cdbme-2017-0081.

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AbstractFused deposition modeling as an additive manufacturing technique has gained great popularity for the fabrication of medical devices as well as pharmaceutical dosage forms over the last years. Particularly the variety of geometries that can be printed determines the attractiveness of this technique enabling a shape adaption of e.g. implants. In the presented work the soft hydrogel material glycerol gelatin was investigated towards its applicability in 3D-printing as an alternative to the commonly applied and mostly rigid polyesters. Model implants loaded with the model drug quinine and with the shape of a hollow cylinder were printed via an extrusion based technique utilizing the piston feed in a hydrogel filled heatable syringe. Glycerol gelatin hydrogels need to be crosslinked to avoid gel-sol-transition at body temperature. For this purpose three different crosslinking methods (insertion, dipping, spraying) with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) were evaluated regarding their crosslinking efficiency and drug losses during the crosslinking process. Dipping of the implant into an aqueous solution with at least 50 mM EDC and 10 mM NHS was found to be the most efficient crosslinking technique in conjunction with a smaller drug loss during processing compared to inserting. However, the use of hydrogels also causes problems as an intense and highly variable swelling of the printed structures during crosslinking (120.7 % ± 11.9 % for 10 times dipping in 50mM EDC/10 mM NHS) and a great dependency of the volume on storage conditions complicate the preparation of tailor-made implants. The release of the model drug quinine from printed and crosslinked implants was fast and nearly completed within 6 hours.

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Wissink, M. J. B., M. J. A. van Luyn, R. Beernink, F. Dijk, A. A. Poot, G. H. M. Engbers, T. Beugeling, W. G. van Aken, and J. Feijen. "Endothelial Cell Seeding on Crosslinked Collagen: Effects of Crosslinking on Endothelial Cell Proliferation and Functional Parameters." Thrombosis and Haemostasis 84, no. 08 (2000): 325–31. http://dx.doi.org/10.1055/s-0037-1614015.

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SummaryEndothelial cell seeding, a promising method to improve the performance of small-diameter vascular grafts, requires a suitable substrate, such as crosslinked collagen. Commonly used crosslinking agents such as glutaraldehyde and formaldehyde cause, however, cytotoxic reactions and thereby hamper endothelialization of currently available collagen-coated vascular graft materials.The aim of this study was to investigate the effects of an alternative method for crosslinking of collagen, using N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide (EDC) in combination with N-hydroxysuccinimide (NHS), on various cellular functions of human umbilical vein endothelial cells (HUVECs) in vitro. Compared to non-crosslinked type I collagen, proliferation of seeded endothelial cells was significantly increased on EDC/NHS-crosslinked collagen. Furthermore, higher cell numbers were found with increasing crosslink densities. Neither the morphology of the cells nor the secretion of prostacyclin (PGI2), von Willebrand factor (vWF), tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1) was affected by the crosslink density of the collagen substrate. Therefore, EDC/NHScrosslinked collagen is candidate substrate for in vivo application such as endothelial cell seeding of collagen-coated vascular grafts.

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Pieper, J. S., T. Hafmans, J. H. Veerkamp, and T. H. van Kuppevelt. "Development of tailor-made collagen–glycosaminoglycan matrices: EDC/NHS crosslinking, and ultrastructural aspects." Biomaterials 21, no. 6 (March 2000): 581–93. http://dx.doi.org/10.1016/s0142-9612(99)00222-7.

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Krishnamoorthy, Ganesan, Praveen Kumar Sehgal, Asit Baran Mandal, and Sayeed Sadulla. "Novel collagen scaffolds prepared by using unnatural D-amino acids assisted EDC/NHS crosslinking." Journal of Biomaterials Science, Polymer Edition 24, no. 3 (August 13, 2012): 344–64. http://dx.doi.org/10.1080/09205063.2012.690280.

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12

Tian, Kun, Dong Hua Guan, Ping Wu, Chun Peng Huang, Lin Niu, Su Qin Xian, Yu Chen, et al. "Controlled Crystallization of Tooth-Like Hydroxyapatite under Gelatin Monolayer." Key Engineering Materials 330-332 (February 2007): 663–66. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.663.

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Based on the molecular recognition theory, an organic molecules model was designed to induce the hydroxyapatite crystallization, to build a tooth-like calcium phosphate/hydroxyapatite under a controllable way in vitro. The cross-linking of collagen on the dentin surface and gelatin was optimized by varying the molar ratio of N,N-(3-dimethylaminopropyl)- N'-ethyl-carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) at a constant EDC concentration. CaCl2 and Na3PO4-12H2O solutions were added after the crosslinking process. The whole process requires repeating the crosslinking and mineralization process for five times. The obtained composite were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) as well as energy dispersive X-ray photoelectron spectroscopy (XPS). The results showed that the dentinal tubule were blocked by neonatal hydroxyapatite layer which has a continuous structure of columns crystal with size of 10-40nm. Furthermore, there was column crystal with parallel direction inside, similar to the crystal array in the top of enamel rod. This study showed that the specific organic molecule model can be used as a potential effective crystal growth modifier.

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Hua, Jiachuan, Zheng Li, Wen Xia, Ning Yang, Jixian Gong, Jianfei Zhang, and Changsheng Qiao. "Preparation and properties of EDC/NHS mediated crosslinking poly (gamma-glutamic acid)/epsilon-polylysine hydrogels." Materials Science and Engineering: C 61 (April 2016): 879–92. http://dx.doi.org/10.1016/j.msec.2016.01.001.

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Diogo, Gabriela, Estefania López-Senra, Rogério Pirraco, Raphael Canadas, Emanuel Fernandes, Julia Serra, Ricardo Pérez-Martín, et al. "Marine Collagen/Apatite Composite Scaffolds Envisaging Hard Tissue Applications." Marine Drugs 16, no. 8 (August 3, 2018): 269. http://dx.doi.org/10.3390/md16080269.

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The high prevalence of bone defects has become a worldwide problem. Despite the significant amount of research on the subject, the available therapeutic solutions lack efficiency. Autografts, the most commonly used approaches to treat bone defects, have limitations such as donor site morbidity, pain and lack of donor site. Marine resources emerge as an attractive alternative to extract bioactive compounds for further use in bone tissue-engineering approaches. On one hand they can be isolated from by-products, at low cost, creating value from products that are considered waste for the fish transformation industry. One the other hand, religious constraints will be avoided. We isolated two marine origin materials, collagen from shark skin (Prionace glauca) and calcium phosphates from the teeth of two different shark species (Prionace glauca and Isurus oxyrinchus), and further proposed to mix them to produce 3D composite structures for hard tissue applications. Two crosslinking agents, 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride/N-Hydroxysuccinimide (EDC/NHS) and hexamethylene diisocyanate (HMDI), were tested to enhance the scaffolds’ properties, with EDC/NHS resulting in better properties. The characterization of the structures showed that the developed composites could support attachment and proliferation of osteoblast-like cells. A promising scaffold for the engineering of bone tissue is thus proposed, based on a strategy of marine by-products valorisation.

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Kołbuk, Dorota, Marcin Heljak, Emilia Choińska, and Olga Urbanek. "Novel 3D Hybrid Nanofiber Scaffolds for Bone Regeneration." Polymers 12, no. 3 (March 2, 2020): 544. http://dx.doi.org/10.3390/polym12030544.

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Development of hybrid scaffolds and their formation methods occupies an important place in tissue engineering. In this paper, a novel method of 3D hybrid scaffold formation is presented as well as an explanation of the differences in scaffold properties, which were a consequence of different crosslinking mechanisms. Scaffolds were formed from 3D freeze-dried gelatin and electrospun poly(lactide-co-glicolide) (PLGA) fibers in a ratio of 1:1 w/w. In order to enhance osteoblast proliferation, the fibers were coated with hydroxyapatite nanoparticles (HAp) using sonochemical processing. All scaffolds were crosslinked using an EDC/NHS solution. The scaffolds’ morphology was imaged using scanning electron microscopy (SEM). The chemical composition of the scaffolds was analyzed using several methods. Water absorption and mass loss investigations proved a higher crosslinking degree of the hybrid scaffolds than a pure gelatin scaffold, caused by additional interactions between gelatin, PLGA, and HAp. Additionally, mechanical properties of the 3D hybrid scaffolds were higher than traditional hydrogels. In vitro studies revealed that fibroblasts and osteoblasts proliferated and migrated well on the 3D hybrid scaffolds, and also penetrated their structure during the seven days of the experiment.

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Kang, Pei-Leun, Yu-Hsin Lin, Kalpana Settu, Ching-Shu Yen, Chin-Yi Yeh, Jen-Tsai Liu, Ching-Jung Chen, and Shwu-Jen Chang. "A Facile Fabrication of Biodegradable and Biocompatible Cross-Linked Gelatin as Screen Printing Substrates." Polymers 12, no. 5 (May 22, 2020): 1186. http://dx.doi.org/10.3390/polym12051186.

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This study focuses on preparation and valuation of the biodegradable, native, and modified gelatin film as screen-printing substrates. Modified gelatin film was prepared by crosslinking with various crosslinking agents and the electrode array was designed by screen-printing. It was observed that the swelling ratio of C-2, crosslinked with glutaraldehyde and EDC/NHS (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide) was found to be lower (3.98%) than that of C-1 (crosslinked with only glutaraldehyde) (8.77%) and C-0 (without crosslinking) (28.15%). The obtained results indicate that the swelling ratios of both C-1 and C-2 were found to be lower than that of C-0 (control one without crosslinking). The Young’s modulus for C-1 and C-2 was found to be 8.55 ± 0.57 and 23.72 ± 2.04 kPa, respectively. Hence, it was conveyed that the mechanical strength of C-2 was found to be two times higher than that of C-l, suggesting that the mechanical strength was enhanced upon dual crosslinking in this study also. The adhesion study indicates that silver ink adhesion on the gelation surface is better than that of carbon ink. In addition, the electrical response of C-2 with a screen-printed electrode (SPE) was found to be the same as the commercial polycarbonate (PC) substrate. The result of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay suggested that the silver SPE on C-2 was non-cytotoxic toward L929 fibroblast cells proliferation. The results indicated that C-2 gelatin is a promising material to act as a screen-printing substrate with excellent biodegradable and biocompatible properties.

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Tian, Kun, Hui Min Shuai, and Xiao Min Yang. "Biomimetic Synthesis of Tooth-Like Hydroxyapatite under Organic Polymer Monolayer." Materials Science Forum 610-613 (January 2009): 1054–58. http://dx.doi.org/10.4028/www.scientific.net/msf.610-613.1054.

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Based on the basic theory of molecular recognition , we design a organic molecules model to induce the crystallization of hydroxyapatite to synthesized tooth-like calcium phosphate/hydroxyapatite under a controllable way in vitro. The cross-linking of collagen on the dentin surface and extraneous collagen was optimized by varying the molar ratio of N,N-(3-dimethylaminopropyl)- N'-ethyl-carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) at a constant EDC concentration. CaCl2 and Na3PO4-12H2O solutions were added after the crosslinking process. X-ray photoelectron spectroscopic (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis of organic protein monolayer for samples. The obtained composite were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) as well as energy dispersive X-ray (EDX). XPS and FTIR analysis showed the surface organic compositions in experimental group is higher than that of normal dentin and decalcified dentin surface. The results showed that the dentinal tubule were blocked by neonatal hydroxyapatite layer which has a continuous structure of columns crystal with size of 10-40nm. Furthermore, there were column crystal with parallel direction inside, similar to the crystal array in the top of enamel rod. This study showed that the specific organic molecule model can be used as a potential effective crystal growth modifier.

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Campos, Yaima, Francisco J. Sola, Gastón Fuentes, Luis Quintanilla, Amisel Almirall, Luis J. Cruz, José C. Rodríguez-Cabello, and Yasuhiko Tabata. "The Effects of Crosslinking on the Rheology and Cellular Behavior of Polymer-Based 3D-Multilayered Scaffolds for Restoring Articular Cartilage." Polymers 13, no. 6 (March 16, 2021): 907. http://dx.doi.org/10.3390/polym13060907.

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Polymer-based tri-layered (bone, intermediate and top layers) scaffolds used for the restoration of articular cartilage were prepared and characterized in this study to emulate the concentration gradient of cartilage. The scaffolds were physically or chemically crosslinked. In order to obtain adequate scaffolds for the intended application, the impact of the type of calcium phosphate used in the bone layer, the polymer used in the intermediate layer and the interlayer crosslinking process were analyzed. The correlation among SEM micrographs, physical-chemical characterization, swelling behavior, rheological measurements and cell studies were examined. Storage moduli at 1 Hz were 0.3–1.7 kPa for physically crosslinked scaffolds, and 4–5 kPa (EDC/NHS system) and 15–20 kPa (glutaraldehyde) for chemically crosslinked scaffolds. Intrinsic viscoelasticity and poroelasticity were considered in discussing the physical mechanism dominating in different time/frequency scales. Cell evaluation showed that all samples are available as alternatives to repair and/or substitute cartilage in articular osteoarthritis.

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Zhang, Mingkai, Yang Gao, Jialiang Wang, Zhanbo Liu, Zaishun Jin, Jianbo Yu, Yukuan Feng, and Qiang Lü. "Identification on Mantle Cell Lymphoma Using CD20 and CD5 Coupled Upconversion Fluorescent Nanoprobes." Journal of Nanomaterials 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/3893761.

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In order to determine a particular tumor cell via nanomaterials, we introduce the preparation of CD20 and CD5 coupled nanoprobes (denoted as CD20 and CD5 nanoprobes for convenience) and an application in identification of mantle cell lymphoma (MCL) from B-cell lymphoma. In this work, CD20 and CD5 nanoprobes were prepared by selectively oxidizing the carbon-carbon double bonds of oleate ligands on the surfaces of NaYF4:Yb3+,Tm3+ and NaYF4:Yb3+,Er3+ nanoparticles and, respectively, coupling carboxyl groups on the particles’ surfaces with CD20 and CD5 monoclonal antibodies through EDC/NHS crosslinking agents. After in situ hybridized Jeko-1 cells and Raji cells as a reference with CD20 and CD5 nanoprobes, in vitro double-color upconversion fluorescence imaging of Jeko-1 cells was demonstrated through visualization of blue and green fluorescence under a 980 nm laser excitation. Moreover, in vivo upconversion fluorescence imaging of the transplanted cancer model was also measured. These experimental results indicate that Jeko-1 cells have been specifically labeled by CD20 and CD5 nanoprobes. It is therefore concluded that CD20 and CD5 nanoprobes could be used to specially differentiate mantle cell lymphoma (MCL) from B-cell lymphoma.

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Pinilla-Torres, Ana M., Paola Y. Carrión-García, Celia N. Sánchez-Domínguez, Hugo Gallardo-Blanco, and Margarita Sánchez-Domínguez. "Modification of Branched Polyethyleneimine Using Mesquite Gum for Its Improved Hemocompatibility." Polymers 13, no. 16 (August 17, 2021): 2766. http://dx.doi.org/10.3390/polym13162766.

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In the present study, the modification of branched polyethyleneimine (b-PEI) was carried out using mesquite gum (MG) to improve its hemocompatibility to be used in biomedical applications. In the copolymer synthesis process (carboxymethylated mesquite gum grafted polyethyleneimine copolymer (CBX-MG-PEI), an MG carboxymethylation reaction was initially carried out (carboxymethylated mesquite gum (CBX-MG). Subsequently, the functionalization between CBX-MG and b-PEI was carried out using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as crosslinking agents. The synthesis products were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). Thermogravimetric analysis showed that CBX-MG and CBX-MG-PEI presented a lower decomposition temperature than MG. The CBX-MG-PEI has a high buffer capacity in the pH range of 4 to 7, similar to the b-PEI. In addition, the CBX-MG-PEI showed an improvement in hemocompatibility in comparison with the b-PEI. The results showed a non-hemolytic property at doses lower than 0.1 µg/mL (CBX-MG-PEI). These results allow us to propose that this copolymer be used in transfection, polymeric nanoparticles, and biomaterials due to its physicochemical and hemocompatibility properties.

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Ghensi, Paolo, Elia Bettio, Devid Maniglio, Emiliana Bonomi, Federico Piccoli, Silvia Gross, Patrizio Caciagli, Nicola Segata, Giandomenico Nollo, and Francesco Tessarolo. "Dental Implants with Anti-Biofilm Properties: A Pilot Study for Developing a New Sericin-Based Coating." Materials 12, no. 15 (July 30, 2019): 2429. http://dx.doi.org/10.3390/ma12152429.

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Aim: several strategies have been tested in recent years to prevent bacterial colonization of dental implants. Sericin, one of the two main silk proteins, possesses relevant biological activities and also literature reports about its potential antibacterial properties, but results are discordant and not yet definitive. The aim of this study was to evaluate the effectiveness of different experimental protocols in order to obtain a sericin-based coating on medical grade titanium (Ti) able to reduce microbial adhesion to the dental implant surface. Materials and Methods: different strategies for covalent bonding of sericin to Ti were pursued throughout a multi-step procedure on Ti-6Al-4V disks. The surface of grade 5 Ti was initially immersed in NaOH solution to obtain the exposure of functional -OH groups. Two different silanization strategies were then tested using aminopropyltriethoxysilane (APTES). Eventually, the bonding between silanized Ti-6Al-4V and sericin was obtained with two different crosslinking processes: glutaraldehyde (GLU) or carbodiimide/N-Hydroxy-succinimide (EDC/NHS). Micro-morphological and compositional analyses were performed on the samples at each intermediate step to assess the most effective coating strategy able to optimize the silanization and bioconjugation processes. Microbiological tests on the coated Ti-6Al-4V disks were conducted in vitro using a standard biofilm producer strain of Staphylococcus aureus (ATCC 6538) to quantify the inhibition of microbial biofilm formation (anti-biofilm efficacy) at 24 hours. Results: both silanization techniques resulted in a significant increase of silicon (Si) on the Ti-6Al-4V surfaces etched with NaOH. Differences were found between GLU and EDC/NHS bioconjugation strategies in terms of composition, surface micro-morphology and anti-biofilm efficacy. Ti-6Al-4V samples coated with GLU-bound sericin after silanization obtained via vapor phase deposition proved that this technique is the most convenient and effective coating strategy, resulting in a bacterial inhibition of about 53% in respect to the uncoated Ti-6Al-4V disks. Conclusions: The coating with glutaraldehyde-bound sericin after silanization in the vapor phase showed promising bacterial inhibition values with a significant reduction of S. aureus biofilm. Further studies including higher number of replicates and more peri-implant-relevant microorganisms are needed to evaluate the applicability of this experimental protocol to dental implants.

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Sharma, Archana, Sumrita Bhat, Tanushree Vishnoi, Vijayashree Nayak, and Ashok Kumar. "Three-Dimensional Supermacroporous Carrageenan-Gelatin Cryogel Matrix for Tissue Engineering Applications." BioMed Research International 2013 (2013): 1–15. http://dx.doi.org/10.1155/2013/478279.

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A tissue-engineered polymeric scaffold should provide suitable macroporous structure similar to that of extracellular matrix which can induce cellular activities and guide tissue regeneration. Cryogelation is a technique in which appropriate monomers or polymeric precursors frozen at sub-zero temperature leads to the formation of supermacroporous cryogel matrices. In this study carrageenan-gelatin (natural polymers) cryogels were synthesized by using glutaraldehyde and 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride andN-hydroxysuccinimide (EDC-NHS) as crosslinking agent at optimum concentrations. Matrices showed large and interconnected pores which were in the range of 60–100 μm diameter. Unconfined compression analysis showed elasticity and physical integrity of all cryogels, as these matrices regained their original length after 90% compressing from the original size. Moreover Young’s modulus was found to be in the range of 4–11 kPa for the dry cryogel sections. These cryogels also exhibited goodin vitrodegradation capacity at 37 °C within 4 weeks of incubation. Supermacroporous carrageenan-gelatin cryogels showed efficient cell adherence and proliferation of Cos-7 cells which was examined by SEM. PI nuclear stain was used to observe cell-matrix interaction. Cytotoxicity of the scaffolds was checked by MTT assay which showed that cryogels are biocompatible and act as a potential material for tissue engineering and regenerative medicine.

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Gao, Yingjun, Xing Zhang, and Xiangyu Jin. "Preparation and Properties of Minocycline-Loaded Carboxymethyl Chitosan Gel/Alginate Nonwovens Composite Wound Dressings." Marine Drugs 17, no. 10 (October 11, 2019): 575. http://dx.doi.org/10.3390/md17100575.

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As derivatives from marine natural biomaterials, alginate-based and chitosan-based biomaterials are commonly used in wound dressings. Calcium alginate fiber (CAF) dressings possess excellent absorption and unique gel forming performance, but the low bioactivity limits its application in wound healing. Carboxymethyl chitosan (CM-Chit) has excellent antibacterial activity, but the gel structure with weak mechanical properties restricts its application. In this study, minocycline (Mino)/CM-Chit solution was coated on the surface of plasma treated CAF needle-punched nonwovens, and then Mino loaded CM-Chit gel/CAF nonwovens composite dressings were fabricated by EDC/NHS (1-3-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide) crosslinking. The dressings had a porous composite structure, which allowed them to quickly absorb and store a large number of wound exudates. Skin-like tensile performance allowed the dressings to provide a better healing environment. Antibacterial assay against Escherichia coli and Staphylococcus aureus indicated that the addition of Mino significantly improved the antibacterial activity of the wound dressings. The tight structure of CM-Chit gel prevented the burst release of Mino so that the dressings had antibacterial activity in a certain period of release time. Cell culture assay showed that the dressings had excellent cell biocompatibility. As new functional dressings, the prepared composite dressings had excellent potential in the clinical healing of wounds.

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Khan, Niazul I., and Edward Song. "Detection of an IL-6 Biomarker Using a GFET Platform Developed with a Facile Organic Solvent-Free Aptamer Immobilization Approach." Sensors 21, no. 4 (February 13, 2021): 1335. http://dx.doi.org/10.3390/s21041335.

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Aptamer-immobilized graphene field-effect transistors (GFETs) have become a well-known detection platform in the field of biosensing with various biomarkers such as proteins, bacteria, virus, as well as chemicals. A conventional aptamer immobilization technique on graphene involves a two-step crosslinking process. In the first step, a pyrene derivative is anchored onto the surface of graphene and, in the second step, an amine-terminated aptamer is crosslinked to the pyrene backbone with EDC/NHS (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide) chemistry. However, this process often requires the use of organic solvents such as dimethyl formamide (DMF) or dimethyl sulfoxide (DMSO) which are typically polar aprotic solvents and hence dissolves both polar and nonpolar compounds. The use of such solvents can be especially problematic in the fabrication of lab-on-a-chip or point-of-care diagnostic platforms as they can attack vulnerable materials such as polymers, passivation layers and microfluidic tubing leading to device damage and fluid leakage. To remedy such challenges, in this work, we demonstrate the use of pyrene-tagged DNA aptamers (PTDA) for performing a one-step aptamer immobilization technique to implement a GFET-based biosensor for the detection of Interleukin-6 (IL-6) protein biomarker. In this approach, the aptamer terminal is pre-tagged with a pyrene group which becomes soluble in aqueous solution. This obviates the need for using organic solvents, thereby enhancing the device integrity. In addition, an external electric field is applied during the functionalization step to increase the efficiency of aptamer immobilization and hence improved coverage and density. The results from this work could potentially open up new avenues for the use of GFET-based BioMEMS platforms by broadening the choice of materials used for device fabrication and integration.

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Hong, Bo Min, Su A. Park, and Won Ho Park. "Effect of photoinitiator on chain degradation of hyaluronic acid." Biomaterials Research 23, no. 1 (November 21, 2019). http://dx.doi.org/10.1186/s40824-019-0170-1.

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Abstract Objectives Photocrosslinking systems of polymers have been widely studied using UV or visible light irradiation. However, the photodegradation behavior derived from light irradiation was rarely reported, comparing with the photocrosslinking. In this study, the tyramine-modified hyaluronic acid (HA/Tyr) hydrogel was prepared using riboflavin (RF) as a photoinitiator, and the degradation behavior of HA by the reactive oxygen species (ROS) generated in photochemical process was investigated. Materials and methods The HA/Tyr conjugate was synthesized by EDC/NHS chemistry to introduce phenol group. Degree of substitution (DS, %) of phenol group to HA molecule was about 25%. The structural change of HA/Tyr was measured by proton nuclear magnetic resonance (1H-NMR) and attenuated total reflectance infrared spectroscopy (ATR-FTIR), and the rheological properties of photocrosslinked HA/Tyr hydrogel were investigated by rheometer. Results The HA/Tyr solution with 25% substitution formed a stable hydrogel via visible light irradiation in the presence of RF photoinitiator. Rheological data of HA/Tyr solution showed that the storage modulus (G’) was increased with increasing HA concentration. Additionally, it was found that RF initiated by visible light irradiation induced the degradation of HA molecular chain, and consequently reduced the viscosity of HA/Tyr solutions. Conclusion The results indicate that RF-based photoinitiator system caused the degradation of HA molecule by ROS generated in photochemical process as well as the crosslinking of HA/Tyr.

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Picart, Catherine, Ludovic Richert, René Elkaim, Pierre Schaaf, Jean-Claude Voegel, and Benoît Frisch. "Primary osteoblasts adhesion onto RGD-functionalized and cross-linked polyelectrolyte multilayer films." MRS Proceedings 823 (2004). http://dx.doi.org/10.1557/proc-823-w12.1.

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AbstractThe adhesion of primary osteoblastic cells on top of biocompatible polyelectrolyte multilayer (PEM) films was investigated for native films and after changing the films properties either with a chemical stimulus (film functionalization), with a mechanical stimulus (film cross-linking), or with both stimuli combined. For the functionalization, a 15 amino acid peptide containing a –RGD- (-Arg-Gly-Asp) sequence was grafted to poly(L-glutamic) acid and deposited on top of poly(L-lysine)/poly(L-glutamic) (PLL/PGA), PLL/Poly(alginic), and PLL/Poly(galacturonic) films. The film buildup and the adsorption of the PGA-RGD was followed by Optical Waveguide Lightmode Spectroscopy and by Atomic Force Microscopy. The mechanical stimulus was achieved by crosslinking the films with a water soluble carbodiimide (EDC) in combination with N-hydroxysulfo-succinimide (sulfo-NHS) to induce amide formation. Fourier Transform Infrared Spectroscopy evidenced the conversion of amine and carboxylic groups into amide groups.The alkaline phosphatase (ALP) activity test was used to assess osteoblast adhesion and proliferation on top of the different films over a period of eight days in culture. Whereas the native films are poorly adherent, the RGD-functionalized films exhibit an increased short time adhesion. The native films could also be successfully cross-linked thereby dramatically enhancing cell proliferation. The cells did not react similarly on the different types of films investigated : the cross-linked (PLL/Palg) and (PLL/Pgal) films were much more efficient than the native or functionalized films in terms of proliferation. On the other hand, for the (PLL/PGA) films, functionalization and film cross-linking had a similar long term effect. Very interestingly, for these latter films, both stimuli could be combined.

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Haagdorens, Michel, Elle Edin, Per Fagerholm, Marc Groleau, Zvi Shtein, Artūras Ulčinas, Amit Yaari, et al. "Plant Recombinant Human Collagen Type I Hydrogels for Corneal Regeneration." Regenerative Engineering and Translational Medicine, August 6, 2021. http://dx.doi.org/10.1007/s40883-021-00220-3.

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Abstract Purpose To determine feasibility of plant-derived recombinant human collagen type I (RHCI) for use in corneal regenerative implants Methods RHCI was crosslinked with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) to form hydrogels. Application of shear force to liquid crystalline RHCI aligned the collagen fibrils. Both aligned and random hydrogels were evaluated for mechanical and optical properties, as well as in vitro biocompatibility. Further evaluation was performed in vivo by subcutaneous implantation in rats and corneal implantation in Göttingen minipigs. Results Spontaneous crosslinking of randomly aligned RHCI (rRHCI) formed robust, transparent hydrogels that were sufficient for implantation. Aligning the RHCI (aRHCI) resulted in thicker collagen fibrils forming an opaque hydrogel with insufficient transverse mechanical strength for surgical manipulation. rRHCI showed minimal inflammation when implanted subcutaneously in rats. The corneal implants in minipigs showed that rRHCI hydrogels promoted regeneration of corneal epithelium, stroma, and nerves; some myofibroblasts were seen in the regenerated neo-corneas. Conclusion Plant-derived RHCI was used to fabricate a hydrogel that is transparent, mechanically stable, and biocompatible when grafted as corneal implants in minipigs. Plant-derived collagen is determined to be a safe alternative to allografts, animal collagens, or yeast-derived recombinant human collagen for tissue engineering applications. The main advantage is that unlike donor corneas or yeast-produced collagen, the RHCI supply is potentially unlimited due to the high yields of this production method. Lay Summary A severe shortage of human-donor corneas for transplantation has led scientists to develop synthetic alternatives. Here, recombinant human collagen type I made of tobacco plants through genetic engineering was tested for use in making corneal implants. We made strong, transparent hydrogels that were tested by implanting subcutaneously in rats and in the corneas of minipigs. We showed that the plant collagen was biocompatible and was able to stably regenerate the corneas of minipigs comparable to yeast-produced recombinant collagen that we previously tested in clinical trials. The advantage of the plant collagen is that the supply is potentially limitless.

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Journal articles on the topic 'Crosslinking (edc/nhs)'

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