Preparation, characterization, antifungal activity, and mechanism of chitosan/TiO2 hybrid film against bipolaris maydis



A chitosan/TiO2 hybrid film, as a powerful antifungal material for controlling southern corn leaf blight, which is caused by the fungus Bipolaris maydis (B. maydis), was prepared and characterized. Its antifungal activity toward B. maydis was studied, and the experimental results indicate that it had multiple attractive antifungal properties as follows: (1) it displayed strong antifungal activity against B. maydis, with an inhibition ratio of 100% under both visible-light irradiation and in a dark environment; (2) it exhibited a superior antifungal efficacy of 100%, even after 4 h under the irradiation of visible light; and (3) its antifungal activity included the effect of hydroxyl radicals generated by the photocatalysis of TiO2. The antifungal mechanism was attributed to the action of a large amount of positive charges on the structure of the hybrid film, which interacted with the negative charges from the cell and finally resulted in the inactivation of B. maydis. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013