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Chitosan Membranes (chitosan + membrane)
Selected AbstractsAmperometric Immunosensor for Prostate Specific Antigen Based on Co-adsorption of Labeled Antibody and Mediator in Nano-Au Modified Chitosan MembraneCHINESE JOURNAL OF CHEMISTRY, Issue 3 2008Jie-Hua LIN Abstract A quasi-reagentless amperometric immunosensor for prostate specific antigen (PSA) has been developed based on co-adsorption of horseradish peroxidase (HRP) labeled PSA antibody (anti-PSA) and tetramethyl benzidine (TMB) in nano-Au modified chitosan membrane (Au-chitosan). The immobilized TMB was used as an electron transfer mediator, which displayed a surface-controlled process at scan rates less than 45 mV/s, and a diffusion-controlled process at scan rates higher than 45 mV/s. The immunosensor with the co-immobilized anti-PSA and TMB was incubated with sample PSA antigen, and the formed immunoconjugate in the immunosensor was detected by a TMB-H2O2 -HRP electrochemical system. Under the optimal experimental conditions, PSA could be determined in the linear range from 5.0 to 30 ng·mL,1 with a detection limit of 1.0 ng·mL,1. The prepared PSA immunosensor is not only economic due to the low-cost ITO electrode obtained from industrial mass production, but also capable of batch fabrication with acceptable detection and storage stability. [source] Synthesis, Characterization and Ionic Conductive Properties of Phosphorylated Chitosan MembranesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 5-6 2003Ying Wan Abstract Phosphorylated chitosan membranes were prepared from the reaction of orthophosphoric acid and urea on the surface of chitosan membranes in N,N -dimethylformamide. Their ionic conductivity in the wet state was investigated. Chemical modifications contributed to improved ionic conductivities of the chitosan membranes. Compared to the unmodified chitosan membranes, it was found that hydrated phosphorylated chitosan membranes with an appropriate phosphorus content showed an increasing ionic conductivity of about one order of magnitude. The phosphorylation reaction mechanism was explained based on 13C and 31P NMR measurements. It was also observed that the crystallinity of the phosphorylated chitosan membranes and the corresponding swelling indices were changed pronouncedly, but these membranes did not lose either their tensile strength or thermal stability to a significant degree in comparison with the unmodified chitosan membranes. Possible reaction mechanism for preparation of phosphorylated chitosan membranes. [source] Diffusional properties of chitosan hydrogel membranesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2001Barbara Krajewska Abstract Chitosan membranes were prepared by a solvent evaporation technique, followed by crosslinking with glutaraldehyde and coating with BSA. The effects of crosslinking and BSA coating on the pore structure of such prepared hydrogel chitosan membranes were determined. The diffusion rates of 12 non-electrolytes ranging in molecular radius between 2.5 and 14,Å through the membranes were measured, and the results were interpreted in terms of the capillary pore model and free volume model of solute diffusional transport through hydrogel membranes. Glutaraldehyde crosslinking was found to reduce the membrane water content and consequently the membrane pore size and surface porosity, whereas further BSA coating brought about the opposite effect. The latter effect lessened with an increase in glutaraldehyde pretreatment of the membranes. The optimal chitosan membrane preparation, compromising between the solute flux and membrane stability and durability was obtained when the membranes were crosslinked with glutaraldehyde at concentrations between 0.01 and 0.1% (w/w). The knowledge of transport properties and of physical strength of the membranes is of importance for the development of chitosan-based controlled release systems. © 2001 Society of Chemical Industry [source] Plasma-induced grafting of hydroxyethyl methacrylate (HEMA) onto chitosan membranes by a swelling methodPOLYMER INTERNATIONAL, Issue 2 2003Yeping Li Abstract Hydroxyethyl methacrylate (HEMA) was grafted onto chitosan membranes by plasma-graft polymerization. Effects of monomer concentration, plasma power and plasma time on the amount of grafting were investigated. The results showed that there were two processes: grafting polymerization and etching of the membrane. The surface of the grafted membrane was evaluated by FTIR. Scanning electron microscopy indicated that the surface morphology of the grafted membrane could be adjusted through plasma power. Water contact angles of the chitosan surface decreased from 78.2° to 45.4° while the amount of grafting increased from 0 to 12.2%, indicating improved hydrophilicity of the membrane surface. Permeation coefficients through the original membrane, the membrane treated at 55,W for 15,min, and the membrane treated at 55,W for 30,min for creatinine were 9.12,×,10,7, 10.6,×,10,7 and 8.57,×,10,7,cm2,s,1, respectively. Thermogravimetry and mechanical testing showed that there were no significant changes on the bulk property of chitosan membrane after modification. © 2003 Society of Chemical Industry [source] Amperometric Immunosensor for Prostate Specific Antigen Based on Co-adsorption of Labeled Antibody and Mediator in Nano-Au Modified Chitosan MembraneCHINESE JOURNAL OF CHEMISTRY, Issue 3 2008Jie-Hua LIN Abstract A quasi-reagentless amperometric immunosensor for prostate specific antigen (PSA) has been developed based on co-adsorption of horseradish peroxidase (HRP) labeled PSA antibody (anti-PSA) and tetramethyl benzidine (TMB) in nano-Au modified chitosan membrane (Au-chitosan). The immobilized TMB was used as an electron transfer mediator, which displayed a surface-controlled process at scan rates less than 45 mV/s, and a diffusion-controlled process at scan rates higher than 45 mV/s. The immunosensor with the co-immobilized anti-PSA and TMB was incubated with sample PSA antigen, and the formed immunoconjugate in the immunosensor was detected by a TMB-H2O2 -HRP electrochemical system. Under the optimal experimental conditions, PSA could be determined in the linear range from 5.0 to 30 ng·mL,1 with a detection limit of 1.0 ng·mL,1. The prepared PSA immunosensor is not only economic due to the low-cost ITO electrode obtained from industrial mass production, but also capable of batch fabrication with acceptable detection and storage stability. [source] Preparation of novel ZSM-5 zeolite-filled chitosan membranes for pervaporation separation of dimethyl carbonate/methanol mixturesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2007Bingbing Liu Abstract Novel mixed matrix membranes were prepared by incorporating ZSM-5 zeolite into chitosan polymer for the pervaporative separation of dimethyl carbonate (DMC) from methanol. These membranes were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) to assess their morphology, intermolecular interactions, and crystallinity. Sorption studies indicated that the degree of swelling for zeolite-filled membranes increased with zeolite content in the membrane increasing and the separation selectivity of DMC/methanol was dominated by solubility selectivity rather than diffusivity selectivity. The characteristics of these membranes for separating DMC/methanol mixtures were investigated by varying zeolite content, feed composition, and operating temperature. The pervaporation separation index (PSI) showed that 5 wt % of ZSM-5 zeolite-filled membrane gave the optimum performance in the PV process. From the temperature-dependent permeation values, the Arrhenius activation parameters were estimated. The resulting lower activation energy values obtained for zeolite-filled membranes contribute to the framework of the zeolite. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Effects of chitosan solution concentration and incorporation of chitin and glycerol on dense chitosan membrane propertiesJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2007Paula Rulf Marreco Dallan Abstract The aim of this work was to perform a systematic study about the effects induced by chitosan solution concentration and by chitin or glycerol incorporation on dense chitosan membranes with potential use as burn dressings. The membrane properties analyzed were total raw material cost, thickness, morphology, swelling ratio, tensile strength, percentage of strain at break, crystallinity, in vitro enzymatic degradation with lysozyme, and in vitro Vero cells adhesion. While the use of the most concentrated chitosan solution (2.5% w/w) increased membrane cost, it also improved the biomaterial mechanical resistance and ductility, as well as reduced membrane degradation when exposed for 2 months to lysozyme. The remaining evaluated properties were not affected by initial chitosan solution concentration. Chitin incorporation, on the other hand, reduced the membranes cost, swelling ratio, mechanical properties, and crystallinity, resulting in thicker biomaterials with irregular surface more easily degradable when exposed to lysozyme. Glycerol incorporation also reduced the membranes cost and crystallinity and increased membranes degradability after exposure to lysozyme. Strong Vero cells adhesion was not observed in any of the tested membrane formulations. The overall results indicate that the majority of the prepared membranes meet the performance requirements of temporary nonbiodegradable burn dressings (e.g. adequate values of mechanical resistance and ductility, low values of in vitro cellular adhesion on their surfaces, low extent of degradation when exposed to lysozyme solution, and high stability in aqueous solutions). © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007 [source] Pervaporation of tertiary butanol/water mixtures through chitosan membranes cross-linked with toluylene diisocyanate,JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 12 2005Smitha Biduru Abstract Membranes made from 84% deacetylated chitosan biopolymer were cross-linked by a novel method using 2,4-toluylene diisocyanate (TDI) and tested for the separation of t -butanol/water mixtures by pervaporation. The unmodified and cross-linked membranes were characterized by Fourier transform infra red (FTIR) spectroscopy, X-ray diffraction (XRD) studies and sorption studies in order to understand the polymer,liquid interactions and separation mechanisms. Thermal stability was analyzed by differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA) while tensile strength measurement was carried out to assess mechanical strength. The membrane appears to have good potential for breaking the aqueous azeotrope of 88.2 wt% t -butanol by giving a high selectivity of 620 and substantial water flux (0.38 kg m,2 hr,1). The effects of operating parameters such as feed composition, membrane thickness and permeate pressure on membrane performance were evaluated. Copyright © 2005 Society of Chemical Industry [source] Diffusional properties of chitosan hydrogel membranesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2001Barbara Krajewska Abstract Chitosan membranes were prepared by a solvent evaporation technique, followed by crosslinking with glutaraldehyde and coating with BSA. The effects of crosslinking and BSA coating on the pore structure of such prepared hydrogel chitosan membranes were determined. The diffusion rates of 12 non-electrolytes ranging in molecular radius between 2.5 and 14,Å through the membranes were measured, and the results were interpreted in terms of the capillary pore model and free volume model of solute diffusional transport through hydrogel membranes. Glutaraldehyde crosslinking was found to reduce the membrane water content and consequently the membrane pore size and surface porosity, whereas further BSA coating brought about the opposite effect. The latter effect lessened with an increase in glutaraldehyde pretreatment of the membranes. The optimal chitosan membrane preparation, compromising between the solute flux and membrane stability and durability was obtained when the membranes were crosslinked with glutaraldehyde at concentrations between 0.01 and 0.1% (w/w). The knowledge of transport properties and of physical strength of the membranes is of importance for the development of chitosan-based controlled release systems. © 2001 Society of Chemical Industry [source] Synthesis, Characterization and Ionic Conductive Properties of Phosphorylated Chitosan MembranesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 5-6 2003Ying Wan Abstract Phosphorylated chitosan membranes were prepared from the reaction of orthophosphoric acid and urea on the surface of chitosan membranes in N,N -dimethylformamide. Their ionic conductivity in the wet state was investigated. Chemical modifications contributed to improved ionic conductivities of the chitosan membranes. Compared to the unmodified chitosan membranes, it was found that hydrated phosphorylated chitosan membranes with an appropriate phosphorus content showed an increasing ionic conductivity of about one order of magnitude. The phosphorylation reaction mechanism was explained based on 13C and 31P NMR measurements. It was also observed that the crystallinity of the phosphorylated chitosan membranes and the corresponding swelling indices were changed pronouncedly, but these membranes did not lose either their tensile strength or thermal stability to a significant degree in comparison with the unmodified chitosan membranes. Possible reaction mechanism for preparation of phosphorylated chitosan membranes. [source] Plasma-induced grafting of hydroxyethyl methacrylate (HEMA) onto chitosan membranes by a swelling methodPOLYMER INTERNATIONAL, Issue 2 2003Yeping Li Abstract Hydroxyethyl methacrylate (HEMA) was grafted onto chitosan membranes by plasma-graft polymerization. Effects of monomer concentration, plasma power and plasma time on the amount of grafting were investigated. The results showed that there were two processes: grafting polymerization and etching of the membrane. The surface of the grafted membrane was evaluated by FTIR. Scanning electron microscopy indicated that the surface morphology of the grafted membrane could be adjusted through plasma power. Water contact angles of the chitosan surface decreased from 78.2° to 45.4° while the amount of grafting increased from 0 to 12.2%, indicating improved hydrophilicity of the membrane surface. Permeation coefficients through the original membrane, the membrane treated at 55,W for 15,min, and the membrane treated at 55,W for 30,min for creatinine were 9.12,×,10,7, 10.6,×,10,7 and 8.57,×,10,7,cm2,s,1, respectively. Thermogravimetry and mechanical testing showed that there were no significant changes on the bulk property of chitosan membrane after modification. © 2003 Society of Chemical Industry [source] Atom force microscopic characterisation of the interaction forces between bovine serum albumin and cross-linked alkylated chitosan membranes in media of different pHPOLYMER INTERNATIONAL, Issue 12 2002Wen Guang Liu Abstract Butyl, octyl and hexadecyl moieties were introduced into chitosan. The adhesion of bovine serum albumin (BSA) onto glucose aldehyde-crosslinked alkylated chitosan membranes in pH media was investigated by probing the force-displacement curves with BSA-coated Atom force microscope (AFM) tips. The results indicated that, at the isoelectric point (IP), the sample membranes exhibited higher adhesion forces; and deviating from IP ie at pH 2, pH 6, the adhesion forces decreased. The adhesion forces at pH 2 are less than those at pH 6 due to the presence of electrostatic repulsive and attractive interactions, respectively. Measurements of the adhesion force confirmed quantitatively that the introduction of hydrophobic side-chains to chitosan can facilitate protein adsorption; however, longer flexible side-chains can depress protein adsorption to a certain degree. From an analyses of the adhesion forces, it is proposed that protein adsorption can be tuned by adjusting the lengths of the introduced side-alkyl moieties. © 2002 Society of Chemical Industry [source] Culture of nasal epithelial cells using chitosan-based membranesTHE LARYNGOSCOPE, Issue 10 2009Tsung-Wei Huang MD Abstract Objectives/Hypothesis: The aim of this study was to evaluate whether chitosan-based membranes can be used as scaffolds for growth and differentiation of nasal epithelial cells (NECs). Our final goal was to establish a novel methodology for enhancing the regeneration of the respiratory system. Study Design: Prospective study. Methods: Human NECs were cultured on three various substrates, e.g., chitosan membranes, collagen, and chitosan-collagen membranes. Morphology of NECs was examined via light and electron microscopy, the area of ciliated cells was measured by confocal microscopy, and ciliary beat frequency was also evaluated. Expression of mucin genes was investigated with reverse-transcription polymerase chain reaction. Results: NECs were found to be successfully adhesive with collagen and chitosan-collagen membranes at day 3 after seeding, but not with chitosan membranes. The cilia area on collagen were 6.1% ± 1.2%, 8.4% ± 1.4%, and 12.5% ± 1.9% at days 7, 14, and 21 after confluence, respectively, compared with 5.1% ± 0.9%, 8.6% ± 1.6%, and 12.3% ± 2.1% in chitosan-collagen membranes, exhibited nonsignificant difference (P > .05). There were no significant differences in ciliary beat frequency between each group. The expression levels of mucin genes, namely, MUC5AC, MUC5B, and MUC2, in NECs on both collagen and chitosan-collagen membranes did not differ significantly (P > .05). Conclusions: A small amount collagen mixed with chitosan substrate may improve the biocompatibility and promote the mucociliary differentiation in NECs. It appears that chitosan-collagen membrane is a promising scaffold for culture of the nasal epithelium, which sets the stage for studying tissue regeneration in the respiratory system. Laryngoscope, 2009 [source] Effect of spatial architecture on cellular colonizationBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2006Yan Huang Abstract The spatial cell-material interaction remains vital issue in forming biodegradable scaffolds in Tissue Engineering. In this study, to understand the influence of spatial architecture on cellular behavior, 2D and 3D chitosan scaffolds of 50,190 kD and >310 kD MW were synthesized through air drying and controlled rate freezing/lypohilization technique, respectively. In addition, chitosan was emulsified with 19, 76, and 160 kD 50:50 poly lactide-co-glycolide (PLGA) using 1,2-Dimyristoyl-sn-Glycero-3-Phosphocholine (DMPC) as stabilizer. 2D and 3D scaffolds were formed by air drying and lyophilization as before. Tensile and compressive properties of films and scaffolds were analyzed in wet conditions at 37°C. Alterations in the cell spreading, proliferation, and cytoskeletal organization of human umbilical vein endothelial cells (HUVECs) and mouse embryonic fibroblasts (MEFs) were studied. These results showed that the formed 3D chitosan scaffolds had interconnected open pore architecture (50,200 µm size). HUVECs and MEFs had reduced spreading areas and circular morphology on 2D chitosan membranes compared with 3D chitosan scaffolds. The fluorescence photomicrographs for actin (using Alexa Fluor 488 phalloidin) and cytoplasm staining (using carboxyfluorescein diacetate-succinimidyl ester) demonstrated that the cells spread within 3D chitosan matrix. 2D and 3D emulsified chitosan and chitosan/PLGA scaffolds reduced the spreading of HUVECs and MEFs even further. Proliferation results, analyzed via MTT-Formazan assay and BrdU uptake assay, correlated with the spreading characteristics. The reductions in cell spreading area on emulsified surfaces were not detrimental to the viability and endocytic activity but to proliferation. The observed alterations in cellular colonization are in part due to the substrate stiffness and surface topography. In summary, these results suggest a significant influence of spatial architecture on cellular colonization. © 2005 Wiley Periodicals, Inc. [source] | |||||||||||||