Synthesis and characterization of chitosan-TiO<inf>2</inf>:Cu nanocomposite and their enhanced antimicrobial activity with visible light

In the present investigation, novel strategy for the preparation of hybrid nanocomposite containing organic polymer (Chitosan) and inorganic (TiO2:Cu) nanoparticles (NPs) has been developed and demonstrated its biomedical application. The sol–gel and ultra-sonication method assisted for the preparation of uniformly distributed Chitosan-TiO2:Cu (CS-CT) nanocomposite. The structural properties of prepared CS-CT nanocomposite were studied by XRD and FTIR techniques. The XPS was used to estimate elemental composition of the nanocomposite. Thermal properties were studied using TGA. TEM and SEM analysis showed the non-spherical nature of NPs with the average mean diameter 16 nm. The optical properties were analyzed with UV–vis diffuse reflectance spectroscopy to confirm optical absorption in the visible region of light. Where CS-CT showed 200% enhanced light mediated photocatalytic antimicrobial activity against microorganism (Escherichia coli and Staphylococcus aureus) as compared with control. The antimicrobial activity of CS-CT nanocomposite in presence of light is found to be enhanced than that of its components, this is due to synergistic effect of organic and inorganic material complimenting each other's activity. The [rad]OH radicals release studied by PL spectroscopy on the surface of nanocomposite was used to examine antibacterial activity. Cytotoxicity assessment of CS-CT on human fibroblast cells was performed by MTT assay.