Papers by Keyword: Chitosan (CS)

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Authors: Hua'an Zhang, Lin Sun, Wei Wang, Xiao Jun Ma
Abstract: Fibrosis caused by the host response to long-term transplanted microcapsules and the limitation of traditional L929 cell model for biocompatibility testing inspire the development of an assay of biocompatibility based on macrophage behavior. In this paper, the human monocytic cell line THP-1 was utilized for biocompatibility evaluation of microcapsule materials. The cell viability and secretion of nitric oxide (NO) and cytokines served as index of biocompatibility were assayed. It was found that the evaluated microcapsule materials had no effect on the stimulation of NO and cytokines secretion, which meant that these materials were biocompatible. Furthermore, it suggests the THP-1 cell a convenient in vitro experimental model that might be useful for long-term predictions of material biocompatibility.
Authors: Huang Chin Wang, Sy Yuan Kang, Chao Heng Tseng, Wen Cheng Shau, Zhi Yang Chen
Abstract: Formaldehyde (HCHO) which emitted from building materials, such as plywood and adhesive, is a carcinogenic substance in indoor air. Chitosan is produced from the structural element in the exoskeleton of crustaceans (such as crabs and shrimp), and has the ability to absorb HCHO. In this study, the HCHO removal efficiency by chitosan additives was evaluated for two building materials - adhesive and plywood. The experiments were performed in a small chamber based on the method of Japanese Industrial Standards (JIS) A1901 to evaluate the HCHO emission from adhesive and plywood before and after the application of chitosan additives. Both the HCHO concentration in the chamber and the HCHO emission factor of two adhesives, urea-formaldehyde (UF) resin and Poly Vinyl Acetate (PVAC) resin, were reduced from 0.02~0.21 ppm and 0.12~1.05 mg/m2h to 0~0.14 ppm and 0.12~0.63 mg/m2h after using chitosan additives. The best HCHO removal efficiency was adding 9% chitosan additives in the adhesives. The amount of absorbed HCHO is proportional to the amount of chitosan additives, and approximate 0.02 mg of HCHO can be absorbed by per mg of chitosan additive (i.e. absorption capacity 0.02 g HCHO/g Chitosan).
Authors: Jin Ik Lim, Gun Woo Kim, Jae Sik Na, In Sup Noh, Young Sook Son, Chun Ho Kim
Abstract: This study is to develop a novel method for preparation of the chitosan scaffold having interconnected open pore structure and controlled pore distribution. For this, the effects of addition of non-solvent on chitosan solution were estimated. The porous scaffolds were typically prepared by solid-liquid separation and subsequent sublimation of solvent. Alcohol was used as non-solvent for chitosan. The difference of freezing temperature of each of the components induced the liquidliquid and the liquid-solid phase separation via demixing solution (solvent/non-solvent/chitosan). The morphology, heterogeneous pore distribution and mechanical properties of the scaffolds were examined. The addition of non-solvent in chitosan solution was to make the controlled homogeneous micropores and improved interconnectivity between pores without any surface skin layer. For control chitosan scaffold, the pore size was mainly about 80~100 μm. On the contrary, Pore diameters could be controlled mainly within the range 30~100 μm, with a variation of solvent/non-solvent ratio. The number of minute pore (4~25 μm) over chitosan scaffold increased with increasing ratio of non-solvent. New prepared scaffold exhibited larger value of breaking elongation, more elasticity, but less tensile strength than that of control scaffold.
Authors: Zhi Feng Lin, Peng Wang, Dun Zhang, Yi Wang
Abstract: A composite film consisting of ZnO and Chitosan (CS) is obtained on carbon steel via cathodic electrodeposition. Optimal CS concentration of electrodeposition of ZnO/CS film is determined by the method of polarization curves. It is shown that the ZnO/CS film obtained at the concentration of 0.6 g/L has the best corrosion resistance. The deposit is studied by scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR) and X-ray diffraction (XRD). XRD results indicate that ZnO could be fabricated by electrodeposition in composite film. FT-IR results evidence the existence of CS in composite film. SEM results demonstrate that the quality of film is improved because of the addition of CS. The anticorrosion property can be attributed to that the existence of the CS macromolecules can improve the stability of the composite film. This kind of composite film has an anticorrosion application for metal corrosion protection.
Authors: Bing Tao Liu, Remco Fokkink, Arie de Keizer
Abstract: Optical reflectometry is applied as a tool for studying single and simultaneous adsorption of a carbohydrate, a nonionic surfactant, and a protein, For the nonionic surfactant poly(ethylene oxide) alkyl ether on a silica surface the adsorption process is fast and reversible, and the maximum adsorbed amount was 2.45 mg•m-2. Also, the effect of pH on the adsorption of chitosan on silica, and its interaction with C12EO5 have been studied. The maximum adsorbed amount was obtained for pH ≥6.8 (0.80 mg•m-2). Changes in surface functionality upon adsorbing C12EO5 on a chitosan layer and the protein, bovine serum albumin, are reported. The results are discussed in terms of adsorption kinetics, adsorbed mass plateau values, and reversibility of layer formation.
Authors: Shan Ping Li, Jiang Jie Cui
Abstract: We studied the effects of surface modification of bentonite with chitosan on its ability to adsorb Congo Red (CR) dye. The adsorption behavior of CR from aqueous solution onto raw (RB) and chitosan-modified (CMB) bentonite samples was investigated as a function of parameters such as initial CR concentration, contact time, pH and temperature. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to confirm the surface modification. Compared with RB, the adsorption capacity of CMB for CR was greatly enhanced. Kinetic studies indicated that the adsorption of CR on both RB and CMB followed the pseudo-second-order kinetic model. From the thermodynamic parameters, the adsorption of CR on RB and CMB is spontaneous and endothermic. The results indicate that chitosan-modified bentonite provides an important advantage for CR dye adsorption over raw bentonite.
Authors: An Na Wang, Li Gen Wu, Lin Lu Jia, Xiu Ling Li, Yu Dan Sun
Abstract: Tea polyphenol loaded alginate-chitosan microspheres were prepared by ionic gelation method for controlling tea polyphenol release by using various combinations of chitosn and Ca2+ as cation and alginate as anion.Scanning electron microscopy were used to investigate the surface characteristics of tea polyphenol loaded microspheres. These microencapsulated beads were evaluated as a pH-sensitive system for delivery of tea polyphenol. The main advantage of this system is that all procedures used were performed in aqueous medium which may preserve the tea polyphenol bioactivity. At pH7.4, the amounts of tea polyphenol released increased significantly as compared to those released at pH1.2. It is evident that the rate of tea polyphenol release could be controlled by changing the chitosan and the calcium chloride concentrations.
Authors: Jun Hua Cheng, Di Jiang Wen
Abstract: An aqueous photocrosslinkable binder system for tapecasting ceramic substrates was investigated based on chitosan (CS) and polyvinyl alcohol (PVA) by adding UV photoinitiator 2-hydroxy-1- [4-(hydroxyethoxy)phenyl]-2-methyl-1-propanone (Darocur 2959). Alumina green sheets were prepared by using the binder and exposed to UV irradiation. SEM, FT-IR, XRD and DSC verified that these CS/PVA polymeric films or green sheets obtained using the binder were homogeneous, which indicated that CS was compatible with PVA in the binder, polymeric films and green sheets. Blending CS and PVA may created a semi-interpenetratin structure with good mechanical properties enough for handling and machining, and the process may not have oxygen retarding effect in arcylamide system.
Authors: Ismail Peker, Faik N. Oktar, Murat Senol, M. Eroglu
Abstract: Chitosan is a deacetylated derivative of chitin, which is a naturally abundant mucopolysaccharide, supporting the matter of crustaceans, insects, and fungi. Because of its unique properties, such as non-toxicity, biodegradability, and biocompatibility, chitosan has a wide range of applications in various fields. Increasing interest on chitosan’s usage has resulted in high consumption. Therefore, production of chitosan from essential sources with desired characteristics has become an important issue. Several methods, with different chemicals and reaction conditions, have been reported in the literature. This study aimed to shed light in several features of a very promising chitin isolation method described by Tolaimate et al. and its effect on the produced chitosan’s phisico-chemical characteristics.
Authors: Claire Jarry, Matthew Shive, Abdellatif Chenite
Abstract: The primary purpose of this study was to characterize the main features of a BCP-loaded chitosan-GP composite. The two-syringe design improves the storage conditions, facilitates the sterilization procedure and provides an easy-to-use injectable biomaterial, ensuring reproducible properties with minimal manipulation. Rheological measurements confirm that the chitosan- GP/BCP composite retains the thermosensitive properties already described for chitosan-GP hydrogels. At 37°C, the system gels within 10 minutes and reaches sufficient consistency after 30 minutes to prevent the mineral granules from migration into the surrounding tissues in vivo. The compressive force needed for the injection of chitosan-GP/BCP before gelation is approximately 6.6 N, only about 6 times that required for water and much lower than the average force that the majority of adults can exert. Morphology was investigated by environmental scanning electron microscopy (ESEM), which revealed 3-D dispersion of BCP granules embedded in chitosan-GP hydrogel. This open, porous structure affords complete access for body fluids and cells to each mineral granule immediately following implantation. The design using disposable syringes equipped with 16G hypodermic needles described here allows easy in vivo delivery of a fully injectable biomaterial containing porous scaffold that naturally enhances the osteogenic activity recognized for both chitosan and BCP.
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