Quercetin-sensitized TiO2 film: Photocatalytic inhibition of Helminthosporium maydis under visible light irradiation

Abstract A PEG-added sol–gel chemistry approach was used to prepare the nanocrystalline TiO 2 film in its anatase form. It is found that the utilization of polyethylene glycol (PEG) as additive in the preparation process benefits the uniform distribution of the TiO 2 nanoparticles and the corresponding film-forming behavior. Moreover, the sensitized TiO 2 biomaterial film loaded with quercetin was processed by anchoring function groups of the sensitizer onto the surface of TiO 2 substrates through chemical interaction at optimized curing temperature. The as-prepared TiO 2 film was characterized by X-ray diffractometry (XRD), scan electron microscopy (SEM), diffuse reflectance spectroscopy (DRS) and ultraviolet–visible (UV–vis) spectroscopy. The investigation of the anti-fungal activity of quercetin-sensitized TiO 2 film suggests that such photocatalyst effectively inhibited the growth of Helminthosporium maydis ( H. maydis ) under visible light irradiation. Subsequently, the antimicrobial efficiency and inhibition mechanism were further illustrated and discussed by the determination of hydroxyl radicals and lipid peroxidation as well as the measurement of sensitizer redox potential.