Chitosan/polyanion surface modification of styrene-butadiene-styrene block copolymer membrane for wound dressing

The surface of styrene-butadiene-styrene block copolymer (SBS) membrane is modified with tri-steps in this study. At first, two step modified SBS membrane (MSBS) was prepared with epoxidation and ring opening reaction with maleated ionomer. Then chitosan was used as the polycation electrolyte and sodium alginate, poly(γ-glutamic acid) (PGA) and poly(aspartic acid) (PAsp) were selected as polyanion electrolytes to deposit on the surfaces of MSBS membrane by the layer-by-layer self-assembly (LbL) deposition technique to get three [chitosan/polyanion] LbL modified SBS membranes, ([CS/Alg], [CS/PGA] and [CS/PAsp]). From the quantitative XPS analysis and water contact angle measurement, it is found that the order of wettability and the content of functional group percentages of COO(-) and OCN on the three [CS/polyanion] systems are [CS/Alg]>[CS/PGA]>[CS/PAsp]. Performances of water vapor transmission rates, fibronectin adsorption, antibacterial assessment and 3T3 fibroblast cell growth on [CS/Alg], [CS/PGA] and [CS/PAsp] membranes were also evaluated. With the evaluation of water vapor transmission rate, these [CS/Alg], [CS/PGA] and [CS/PAsp] membranes are sterile semipermeable with water evaporation at about 82±8g/day·m(2). It is found that the amount of fibronectin adsorption on the three [CS/polyanion] systems is significantly determined by the sum of the functional group of COO(-) and OCN on the surfaces of [CS/Alg], [CS/PGA] and [CS/PAsp] systems. The results are inverse with the sum of the functional group of COO(-) and OCN on the three [CS/polyanion]. From the cytotoxicity test and cell adhesion and proliferation assay of 3T3 fibroblasts on the three [CS/polyanion] systems, it revealed that the cells not only remained viable but they also proliferated on the surfaces of [CS/Alg], [CS/PGA] and [CS/PAsp]. The bactericidal activity was found on [CS/Alg], [CS/PGA] and [CS/PAsp]. The transport of bacterial through these [CS/polyanion] membranes was also conducted. No bacterial transport was found.