Hetero-nanostructured film of titania nanosheets and lysozyme: Fabrication and synergistic antibacterial properties

Novel hetero-nanostructured multilayer films comprising negatively charged titania nanosheets (TNS) and positively charged natural antibacterial agent, lysozyme (LSZ), have been synthesized by the electrostatic layer-by-layer assembly technique. The resulting films have been characterized using ultraviolet–visible (UV–vis) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). UV–vis spectra show that absorbance values at characteristic wavelengths of multilayer films increase almost linearly with the number of TNS/LSZ bilayers. SEM and AFM images indicate that the surface of the multilayer film is rather smooth and dense. The antibacterial capabilities of multilayer films toward Micrococcus lysodeikticus growth are analyzed using a turbidmetric method. The investigation shows that TNS is a photoactivated antibacterial agent with high inhibition rate, which can help to enhance the antibacterial activity of the multilayer film under UV light irradiation. In the presence of UV light, significant high inhibition rate is observed when the multilayer film is present in turbid bacterial suspension. This hetero-nanostructured multilayer film may potentially be applied as antibacterial coatings.