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Low molecular O-carboxymethyl chitosan, a derivative of chitosan, was conjugated with a hydrophilic carboxymethyl group, following which the conjugate was modified with a furfuryl group. The chitosan derivative was cross-linked to encapsulate a model protein, bovine serum albumin (BSA), in the presence of Rose Bengal under visible light irradiation. The encapsulated BSA was slowly released from the matrix over 2 weeks. The modified chitosan exhibited antimicrobial activity and was non-cytotoxic to NIH3T3 fibroblasts. The wound healing effect of the cross-linked chitosan derivative was examined in Sprague-Dawley rats at 3, 7, and 14 days post-wounding. Cross-linked and murine epidermal growth factor (mEGF)-encapsulated chitosan derivatives healed wounds more rapidly in rats than non-encapsulated mEGF or chitosan derivative alone. Thus, visible light-curable chitosan has good potential for application as wound-healing matrix. [ABSTRACT FROM AUTHOR]

For improving cell adhesion on titanium surface, phosphonated low-molecular-weight chitosan (P-LMC) was prepared by introducing a phosphonate group of 4-phosphonobutyric acid to low-molecular-weight chitosan (3,000

Medical advances have prompted the research and development of biomaterials. Especially, chitosan has emerged as new generation of biomaterials because it beneficial properties as a natural polymer, such as less toxic, biodegradable, and biocompatible than synthetic ones. The prepared azidophenyl O-carboxymethyl chitosan (Az-O-CMC) was characterized by FTIR, H NMR and particle-size analyzer. The hardening rate and cross-linking maintenance of the Az-O-CMC were investigated with its irradiation time and concentration. A photo-mask was used for observation of photoimmobilization. 3T3-L1 cells were cultured to determine effect of cytotoxicity. Protein release test was conducted to evaluate the immobilizing effect. In addition, animal test was investigated for wound healing application. In this study, the results indicate that immobilization of protein with Az-O-CMC will be useful for medical application.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Photoreactive azidophenyl hyaluronic acid (Az-HA) derivative was synthesized to immobilize proteins such as epidermal growth factor (EGF) and bone morphogenetic protein (BMP). The photosensitizing group, 4-azidoaniline, was introduced to the carboxyl group of hyaluronic acid by a water soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). To characterize the synthesized Az-HA, Fourier transform infrared (FTIR), proton nuclear magnetic resonance (H NMR) and ultraviolet/visible (UV/vis) absorbance spectroscopy were performed. We demonstrated protein immobilization by using fluorescein isothiocyanate conjugated albumin (FITCBSA) on Az-HA derivative surfaces that were patterned with micro scale. Cytotoxicity and relative cell proliferation tests of the Az-HA derivative were performed on an MG-63 human osteoblast cell line for biocompatibility. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

In this work, photocurable water-soluble chitosan derivatives were prepared for biomedical applications by modifying water-soluble O-carboxymethyl chitosan ( O-CMC) derivatives with furfuryl glycidyl ether ( O-CMC/FGE). Successful derivatization of chitosan to the final product ( O-CMC/FGE) was verified by UV and H NMR spectral analysis. The degree of photo-crosslinking was measured by a flow distance experiment after exposure to visible light for a certain period of time. The degree of crosslinking increased linearly in proportion to exposure time. The in vitro cell viability test revealed a lack of cytotoxicity of O-CMC/FGE against mouse 3T3 fibroblasts. However, poor cell attachment was observed for the cells seeded onto the photocured O-CMC/FGE; this is likely due to the anionic nature of this material. O-CMC/FGE displayed wound healing effects in an in vivo animal experiment using a burn wound model. Due to its good biocompatibility, wound healing effect, and mild cross-linking condition, together with an inhibitory effect on cell attachment, O-CMC/FGE would be a promising candidate as an anti-adhesion material for biomedical applications. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Adhesions occurring on a variety tissues and operation sites are a serious side effect of surgery and may require additional surgery for removal. Therefore, Furfuryl-fish gelatin (F-f.gel) was synthesized by introducing a furan ring to fish gelatin for application as an anti-adhesion agent. F-f.gel was cured by visible-light irradiation, which changed the material from a solution to a film. The prepared F-f.gel was characterized by proton nuclear magnetic resonance spectroscopy (H NMR), substitution ratio, gel permeation chromatography (GPC), methyl thiazolyl tetrazolium (MTT) assay, and tests for measuring photo immobilization, water contact angle (WCA), and cell attachment. The results showed that F-f.gel was effective as an anti-adhesion agent. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Photo-reactive low molecular-O-carboxymethyl chitosan (LM-O-CMCS) was synthesized by introducing a furfuryl group to the amine groups of LM-O-CMCS. The prepared photo-reactive LM-O-CMCS was characterized by FTIR, H NMR, and a cross-linking test, whereas scanning Auger electron microscopy (SAM) and a MTT assay were used to confirm the cell viability. The water contact angle measurement and cell attachment test were carried out to determine the applicability of LM-O-CMCS as an anti-adhesion agent. [ABSTRACT FROM AUTHOR]

Of a number of actinomycetes isolated from Antarctica and coastal regions of Korea, one isolate, identified as a Streptomyces sp., demulsified an emulsion of kerosene/0.2% Triton X-100 (2:1, v/v) within 1 min. The aerial spores broke emulsions of low viscosity hydrocarbons such as kerosene and gasoline within 1 min, but after 3 min of contact they could demulsify less than 50% of emulsions of high viscosity hydrocarbons diluted with kerosene. [ABSTRACT FROM AUTHOR]