Intracellular ROS Induction by Ag@ZnO Core-Shell Nanoparticles: Frontiers of Permanent Optically Active Holes in Breast Cancer Theranostic.

In this study, we investigated whether ZnO coating on Ag nanoparticles tunes electron flux and hole figuration at Metal-semiconductor interface under UV radiation. This effect triggers photo activity and generation of reactive oxygen species (ROS) from Ag@ZnO nanoparticles which results in enhanced cytotoxic effects and apoptotic cell death in human breast cancer cells (MDA-MB231). In this context, up-regulation of apoptotic cascade proteins (i.e. Bax/Bcl2 association, p53, Cytochrome C and caspase-3) along with activation of oxidative stress proteins suggested occurrence of apoptosis by Ag@ZnO NPs in cancer cells through mitochondrial pathway. Also, pre-incubation of breast cancer cells with Ag@ZnO NPs in dark conditions muted NPs-related toxic effects and consequent apoptotic fate, highlighting biocompatible properties of un-excited Ag@ZnO NPs. Furthermore, diagnostic efficacy of Ag@ZnO NPs as CT/optical nano-probes was investigated. Results confirmed the efficacy of the photo-activated system in obtaining desirable outcomes from CT/optical imaging which, represents novel theranostic NPs for simultaneous cancer imaging and therapy.