Development of part-dissolvable chitosan fibers with surface N-succinylation for wound care dressing

To enhance the liquor absorptivity of chitosan fibers （CS-Fs）, N-succinyl surface-modified chitosan fibers （NSCS-Fs） were developed and evaluated for wound healing, The NSCS-Fs exhibited cracks on the surface and high liquor absorbing capacity with absorbing-dissolvable equilibrium state in phosphate buffer solution （PBS）. The bacteriostasis ratios of NSCS-Fs against E. coli, S. aureus and C. albicans were higher than 80%. No cytotoxicity has been found for mouse embryo fibroblasts （MEFs） treated with NSCS-Fs leach liquor, Acute oral toxicity and skin irritation experiment were taken to evaluate the safety of NSCS-Fs in vitro. Muscle implant study showed that NSCS-Fs were biodegradable and non-toxic in vivo. These results suggested that the surface modified NSCS-Fs had favorable biological properties and improved liquor absorptivity, indicating that they could be used as promising dressing materials for wound care.

Growth of AgBr/Ag_(3)PO_(4) Heterojunction on Chitosan Fibers for Degrading Organic Pollutants

Using Fiber as the based material for photocatalyst particles is favorable for their recovery,thereby avoiding the photocatalyst particles cause secondary pollution to water environment.In this work,the AgBr and Ag_(3)PO_(4) photocatalyst particles were loaded onto the surface of chitosan fiber(CF)via chelation and in situ anion-exchange method.The photocatalytic results illustrated that the AgBr/Ag_(3)PO_(4)/CF composites displayed the best photocatalytic performance when the mass ratio of Ag_(3)PO_(4) and AgBr onto the CF was approximately 1:0.15,their degradation rate can reach 98.1%for the methyl orange(MO)solution,this value far exceeded those of pure CF,AgBr/CF composites,and Ag_(3)PO_(4)/CF composites.Besides,the AgBr/Ag_(3)PO_(4)/CF composites also shown excellent durability,after the fifth cycle,they still maintained a decolorization rate of 86.4%for the MO solution,while the Ag_(3)PO_(4)/CF composites maintained a decolorization rate of only 70.7%.Based on these results,we consider that the AgBr/Ag_(3)PO_(4)/CF composites have high practical interest in environmental remediation.

Sodium carboxymethylation-functionalized chitosan fibers for cutaneous wound healing application

A water absorption biomaterial, sodium carboxymethylation-functiona- lized chitosan fibers （Na-NOCC fibers） were prepared, applied for cutaneous wound repair, and characterized by FTIR and NMR. The water absorption of Na-NOCC fibers increased significantly with substitution degree rising, from 3.2 to 6.8 g/g, and higher than that of chitosan fibers （2.2 g/g） confirmed by swelling behavior. In the antibacterial action, the high degree of substitution of Na-NOCC fibers exhibited stronger antibacterial activities against E. co//（from 66.54% up to 88.86%）. The inhibition of Na-NOCC fibers against S. aureus were above 90%, and more effective than E. coli. The cytotoxicity assay demonstrated that Na-NOCC2 fibers were no obvious cytotoxicity to mouse fibroblasts. Wound healing test and histological examination showed that significantly advanced granulation tissue and capillary formation in the healing-impaired wounds treated with Na-NOCC fibers, as compared to those treated with gauze, which demonstrated that Na- NOCC fibers could promote skin repair and might have great application for wound healing.

Fabrication of Highly Porous Interconnected Three-dimensional Scaffolds with Micro-channels

A novel highly porous 3-D poly（e-caprolactone） （PCL） scaffold with micro-channels was fabricated by injection molding and diluent acetic acids leaching technologies. In this study, the chitosan fiber was employed to form the microchannel in PCL matrix. The morphology, porosity and mechanical properties of the scaffolds were studied and calculated. It was found that the larger the content of chitosan fiber is, the higher the porosity would be, due to the volumetric expansion of chitosan fiber in PCL matrix during it being leached. In addition, the less the content of chitosan fiber is, the higher the compressive modulus would be.