Optically engineered ZnO Nanoparticles: Excitable at visible wavelength and lowered cytotoxicity towards bioimaging applications

Abstract

Tunability of optical properties of ZnO is often rendered for various biomedical applications. Whilst an array of defect-induced ZnO and doped ZnO are available for bioimaging application, their excitability in UV or near-UV range impedes their plausible real-life applications owing to low penetrability or UV light-induced toxicity. This report focuses on developing a Tween-80 guided wet-chemical method for engineering optical properties of pure ZnO nanoparticles to render defects that may have significant impact on bioimaging applications. A substantial decrease in band gap is observed with introduction of Tween 80 as evident from UV–Vis spectroscopy studies. Alteration in band gap facilitates excitation of particles at 488 nm (visible range) which has been exploited to study their uptake in human dermal fibroblasts. Further investigations confirm the high cytocompatibility of the synthesized particles attributed to the altered potential of the valence and conduction bands. Finally, the antibacterial attribute of the ZnO nanoparticles is also confirmed and the bactericidal mechanism has been studied in detail. Owing to its inability to generate superoxide radicals due to the altered potential of conduction and valence bands, the superior and sustained fluorescence property of as-engineered nanoparticles can be explored as a potential alternative in bioimaging applications.