Asymmetric Polyurethane Membrane with In Situ-Generated Nano-TiO2 as Wound Dressing

For potential application as an ideal wound dressing, a novel asymmetric polyurethane membrane with in situ-generated nano-TiO2 (PUNT) was successfully prepared via a combination of solvent evaporation, wet phase inversion, and organic-inorganic hybridization. According to this combination method, the PUNT membrane consisted of an integral and dense skin layer supported by a porous sublayer, with nano-TiO2 particles dispersed evenly throughout the sample. The skin layer was found to be impermeable to bacteria penetration, and the porous sublayer was designed for absorbing high amounts of exudates. Nitrogen adsorption/desorption experiment proved that extra mesopores were created in the PUNT membrane after organic-inorganic hybridization, which resulted in promoted gas permeability, water vapor transmission rate, and exudate absorption capability. The PUNT membrane, as a consequence, could accelerate gas exchange and also provide an optimal level of moisture over the wound beds without risking dehydration or exudate accumulation. Shake flask testing and cell culture (L929) assay indicated that the PUNT membrane exhibited antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, whereas showed no cytotoxicity. From in vivo animal studies, the curative effect of PUNT membrane was found to be better than gauze and a commercial polyurethane membrane dressing. These results indicated that the PUNT membrane with multifunctions prepared in this study has potential for application as an ideal wound dressing. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 1532-1541, 2011