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Huangxian Ju - One of the best experts on this subject based on the ideXlab platform.
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a disposable amperometric immunosensor for α 1 fetoprotein based on enzyme labeled antibody Chitosan Membrane modified screen printed carbon electrode
Analytical Biochemistry, 2004Co-Authors: Hua Yu, Huangxian JuAbstract:Abstract A screen-printed three-electrode system is fabricated to prepare a novel disposable screen-printed immunosensor for rapid determination of α-1-fetoprotein (AFP) in human serum. The immunosensor is prepared by entrapping horseradish peroxidase (HRP)-labeled AFP antibody in Chitosan Membrane to modify the screen-printed carbon electrode. The Membrane is characterized with scanning electron microscope and electrochemical methods. After the immunosensor is incubated with AFP at 30 °C for 35 min, the access of the active center of HRP catalyzing the oxidation reaction of thionine by H2O2 is partly inhibited. In presence of 1.2 mM thionine and 6 mM H2O2, the electrocatalytic current decreases linearly in two concentration ranges of AFP from 0 to 20 and from 20 to 150 ng/mL with a detection limit of 0.74 ng/mL. The immunosensor shows an acceptable accuracy compared with those obtained from immunoradiometric assays. The interassay coefficients of variation are 6.6 and 4.2% at 10 and 100 ng/mL, respectively. The storage stability is acceptable in pH 7.0 phosphate buffer solution at 4 °C for more than 10 days. The proposed method can detect the AFP through one-step immunoassay and would be valuable for clinical immunoassay.
Willem F. Stevens - One of the best experts on this subject based on the ideXlab platform.
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Chitosan Membrane as a wound healing dressing characterization and clinical application
Journal of Biomedical Materials Research Part B, 2004Co-Authors: Abul K Azad, Niwet Sermsintham, Suwalee Chandrkrachang, Willem F. StevensAbstract:Chitosan prepared from natural biopolymer chitin and cast into Membranes has been tested as wound dressing at the skin-graft donor site in patients. Bactigras, a commonly used impregnated tulle gras bandage, served as a control. Chitosan Membrane, prepared with a 75% degree of deacetylation and a thickness of 10 m, was used in nonmesh or mesh form. The progress in wound healing was compared by clinical and histological examination. Itching and pain sensitivity of the wound dressed area was scored with the use of a visual analogue scale. Mesh Chitosan Membrane in contrast to the nonmesh Membrane allowed blood to ooze into the surrounding gauze. After 10 days, the Chitosan-dressed area had been healed more promptly as compared with the Bactigras dressed area. Moreover, the Chitosan mesh mem- brane showed a positive effect on the re-epithelialization and the regeneration of the granular layer. The data confirm that Chitosan mesh Membrane is a potential substitute for human wound dressing. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 216 -222, 2004
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Transdermal Delivery Controlled by a Chitosan Membrane
Drug Development and Industrial Pharmacy, 2004Co-Authors: Wahwah Thein-han, Willem F. StevensAbstract:The release of a drug from a transdermal delivery system with a rate controlling Chitosan Membrane was analyzed in vitro and in vivo. Lidocaine hydrochloride, a local anesthetic, was used as the model drug. The in vitro permeability of various Chitosan Membranes for the drug was investigated using a Franz diffusion cell. Drug release was slower through Chitosan Membranes with a higher degree of deacetylation (% DD) and with a larger thickness. A transdermal Chitosan patch was developed using a Chitosan Membrane for rate control and a Chitosan hydrogel as a drug reservoir. The most prolonged release in vitro was obtained with a 95% DD Chitosan rate controlling Membrane. The transport mechanism was found to be non-Fickian. The functionality of this transdermal patch was studied on the forearm of human volunteers by assessing the anesthetic effect. Patches with 70% and 95% DD Membranes delayed the anesthetic effect, increasing the delay with increasing % DD. It was concluded that a combination of Chitosan Membrane and Chitosan hydrogel is a good transparent system for controlled drug delivery and that the release kinetics in vitro at least for lidocaine have a predictive value for its anesthetic effect in vivo. The demonstration of a direct relationship between in vitro drug Membrane permeability and its physiological effect might be considered as quite unique.
Hua Yu - One of the best experts on this subject based on the ideXlab platform.
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a disposable amperometric immunosensor for α 1 fetoprotein based on enzyme labeled antibody Chitosan Membrane modified screen printed carbon electrode
Analytical Biochemistry, 2004Co-Authors: Hua Yu, Huangxian JuAbstract:Abstract A screen-printed three-electrode system is fabricated to prepare a novel disposable screen-printed immunosensor for rapid determination of α-1-fetoprotein (AFP) in human serum. The immunosensor is prepared by entrapping horseradish peroxidase (HRP)-labeled AFP antibody in Chitosan Membrane to modify the screen-printed carbon electrode. The Membrane is characterized with scanning electron microscope and electrochemical methods. After the immunosensor is incubated with AFP at 30 °C for 35 min, the access of the active center of HRP catalyzing the oxidation reaction of thionine by H2O2 is partly inhibited. In presence of 1.2 mM thionine and 6 mM H2O2, the electrocatalytic current decreases linearly in two concentration ranges of AFP from 0 to 20 and from 20 to 150 ng/mL with a detection limit of 0.74 ng/mL. The immunosensor shows an acceptable accuracy compared with those obtained from immunoradiometric assays. The interassay coefficients of variation are 6.6 and 4.2% at 10 and 100 ng/mL, respectively. The storage stability is acceptable in pH 7.0 phosphate buffer solution at 4 °C for more than 10 days. The proposed method can detect the AFP through one-step immunoassay and would be valuable for clinical immunoassay.
Zhongyi Jiang - One of the best experts on this subject based on the ideXlab platform.
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zeolite beta filled Chitosan Membrane with low methanol permeability for direct methanol fuel cell
Journal of Power Sources, 2008Co-Authors: Yabo Wang, Dong Yang, Xiaohong Zheng, Zhongyi JiangAbstract:Abstract Zeolite beta particles with different sizes and narrow size distribution were hydrothermally synthesized and incorporated into Chitosan (CS) matrix to prepare CS/zeolite beta hybrid Membranes for direct methanol fuel cell (DMFC). It was found that the Chitosan Membrane filled by zeolite beta particles about 800 nm in size exhibited the lowest methanol permeability, which can be ascribed to their optimum free volume and methanol diffusion characteristics. To further improve the performances of CS/zeolite beta hybrid Membranes, zeolite beta particles about 800 nm in size were sulfonated via three different approaches. The results indicated that the introduction of sulfonic groups could reduce the methanol permeability further as a result of the enhanced interfacial interaction between zeolite beta and Chitosan matrix. Furthermore, in terms of the overall selectivity index, CS/zeolite beta hybrid Membranes were comparable to Nafion ® 117 Membrane at low methanol concentration (2 mol L −1 ) and much better at high methanol concentration (12 mol L −1 ).
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surface modified y zeolite filled Chitosan Membrane for direct methanol fuel cell
Journal of Power Sources, 2007Co-Authors: Bin Zheng, Xiaohong Zheng, Jingtao Wang, Weikang Yuan, Zhongyi JiangAbstract:Abstract Hybrid Membranes composed of Chitosan (CS) as organic matrix and surface-modified Y zeolite as inorganic filler are prepared and their applicability for DMFC is demonstrated by methanol permeability, proton conductivity and swelling property. Y zeolite is modified using silane coupling agents, 3-aminopropyl-triethoxysilane (APTES) and 3-mercaptopropyl-trimethoxysilane (MPTMS), to improve the organic–inorganic interfacial morphology. The mercapto group on MPTMS-modified Y zeolite is further oxidized into sulfonic group. Then, the resultant surface-modified Y zeolites with either aminopropyl groups or sulfonicpropyl groups are mixed with Chitosan in acetic acid solution and cast into Membranes. The transitional phase generated between Chitosan matrix and zeolite filler reduces or even eliminates the nonselective voids commonly exist at the interface. The hybrid Membranes exhibit a significant reduction in methanol permeability compared with pure Chitosan and Nafion117 Membranes, and this reduction extent becomes more pronounced with the increase of methanol concentration. By introducing –SO 3 H groups onto zeolite surface, the conductivity of hybrid Membranes is increased up to 2.58 × 10 −2 S cm −1 . In terms of the overall selectivity index ( β = σ / P ), the hybrid Membrane is comparable with Nafion117 at low methanol concentration (2 mol L −1 ) and much better (three times) at high methanol concentration (12 mol L −1 ).
Rong-nan Huang - One of the best experts on this subject based on the ideXlab platform.
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The effect of galectin 1 on 3T3 cell proliferation on Chitosan Membranes.
Biomaterials, 2004Co-Authors: Yu-ying Chang, Huang-chien Liang, Hsing-wen Sung, Shiang-jiuun Chen, Chien-chung Lin, Rong-nan HuangAbstract:Galectin-1 (GAL1), a β-galactoside-binding protein, functions in cell adhesion, development, and growth regulation. A number of studies suggest that GAL1 play an important role in enhancing cell adhesion to extracellular matrix and inducing cell proliferation. Chitosan is a derivative of chitin extracted from lobsters, crabs and shrimps’ exoskeletons. In clinical medicine, Chitosan Membrane had been used as a semi-permeable biological dressing. Although Chitosan Membranes show no cytotoxicity, some cell types (e.g. 3T3 cells) fail to attach and proliferate on their surface. In these studies, we show that over-expression of GAL1 does not enhance 3T3 cell proliferation on Chitosan Membranes. However, coating the Chitosan Membrane with recombinant GAL1 proteins significantly expedites 3T3 cells proliferation. The enhanced cell growth was inhibited by thiodigalactoside (TDG, a potent inhibitor of β-galactoside binding) and GAL1 monoclonal antibodies, suggesting GAL1’s specific effect on the proliferation of 3T3 cells upon Chitosan Membranes. Moreover, immunoblotting detected a markedly suppressed tyrosine phosphorylation in several proteins on 3T3 cell growths upon GAL1-coated Chitosan Membrane. Pretreating the cells with sodium fluoride (NaF, a phosphatase inhibitor) inhibits the attachment and proliferation of 3T3 cells. These findings support a proposed role for altered levels of protein phosphorylation in GAL1-mediated cell attachment and proliferation on Chitosan Membranes.
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fabrication and characterization of a sponge like asymmetric Chitosan Membrane as a wound dressing
Biomaterials, 2001Co-Authors: Fwu Long Mi, S S Shyu, Yubey Wu, Jenyeu Shyong, Rong-nan HuangAbstract:A novel asymmetric Chitosan Membrane has been prepared by immersion–precipitation phase-inversion method and evaluated as wound covering. This new type of Chitosan wound dressing which consists of skin surface on top-layer supported by a macroporous sponge-like sublayer was designed. The thickness of the dense skin surface and porosity of sponge-like sublayer could be controlled by the modification of phase-separation process using per-evaporation method. The asymmetric Chitosan Membrane showed controlled evaporative water loss, excellent oxygen permeability and promoted fluid drainage ability but could inhibit exogenous microorganisms invasion due to the dense skin layer and inherent antimicrobial property of Chitosan. Wound covered with the asymmetric Chitosan Membrane was hemostatic and healed quickly. Histological examination confirmed that epithelialization rate was increased and the deposition of collagen in the dermis was well organized by covering the wound with this asymmetric Chitosan Membrane. The results in this study indicate that the asymmetric Chitosan Membrane thus prepared could be adequately employed in the future as a wound dressing.
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In vitro evaluation of a Chitosan Membrane cross-linked with genipin.
Journal of Biomaterials Science Polymer Edition, 2001Co-Authors: Yu-chiun Tan, Huang-chien Liang, Rong-nan Huang, Hsing-wen SungAbstract:The study was to evaluate the characteristics of a Chitosan Membrane cross-linked with a naturally-occurring cross-linking reagent, genipin. This newly-developed genipin-cross-linked Chitosan Membrane may be used as an implantable drug-delivery system. The Chitosan Membrane without cross-linking (fresh) and the glutaraldehyde-cross-linked Chitosan Membrane were used as controls. The characteristics of test Chitosan Membranes evaluated were their cross-linking degree, swelling ratio, mechanical properties, antimicrobial activity, cytotoxicity, and degradability. It was found that cross-linking of Chitosan Membrane using genipin increased its ultimate tensile strength but significantly reduced its strain-at-fracture and swelling ratio. There was no significant difference in antimicrobial activity between the genipin-cross-linked Chitosan Membrane and its fresh counterpart. Additionally, the results showed that the genipin-cross-linked Chitosan Membrane had a significantly less cytotoxicity and a slower degr...