Optical and antibacterial activity of biogenic core-shell ZnO@TiO2 nanoparticles

Inorganic nanocomposites, due to increased stability and safety, are gaining importance in wide range of engineering and medical applications. In view of this, the present study demonstrates the optical and antibacterial activity of core-shell ZnO@TiO2 nanoparticles synthesized via biogenic method using Azadirachta indica flower extract. The synthesized nanocomposite is characterized by XRD, TEM and EDS. The optical activity of the ZnO@TiO2 nanoparticle, assessed by photoluminescence spectra, indicated concentration dependent increase in the number of defects. The antibacterial activity of synthesized core-shell ZnO@TiO2 nanoparticles was determined by agar disc diffusion method against 9 clinical isolates (Gram positive - S. aureus, S. pneumonia, B. subtilis and Gram negative - E. coli, S. dysenteriae, K. pneumonia, V. cholera, P. aeruginosa, and P. vulgaris). The synthesized nanoparticle exhibited significant antibacterial activity against all the strains tested. The synthesized core-shell ZnO@TiO2 nanoparticle can be a potential antimicrobial candidate for various biomedical applications.