| Abstract Scope |
Cerium oxide nanoparticles (CNPs) modulate cytotoxic reactive oxygen/nitrogen species concentrations via Ce3+/Ce4+ inter-conversion, with equilibrium Ce3+-states, and related oxygen vacancies, influencing particle redox-reaction characters. We hypothesize that Zn/ Cu incorporation (5, 10, and 20 mol%) will influence surface vacancy density and provide additional reaction sites with unique surface chemistry, potentially leading to formation of NPs with broad therapeutic use. Electron microscopy of all samples showed ~5nm spherical particles, while XRD and XPS detailed Zn/Cu phase character. SOD-mimetic radical scavenging was limited across samples (ascribed to low [Ce3+], though increased slightly with increasing Zn/Cu. Interestingly, CAT-mimetic activity varied inversely with Zn-fraction, contrasting SOD trends. Further, Cu introduction showed negligible effect on CAT up to 20 mol%, whereupon activity increased substantially. In-vitro studies (MTT, live/dead assays) confirmed Zn/Cu CNPs imparted targeted cytotoxic/pro-oxidant character toward cancer (MCF-7) cells with anti-oxidant effect on normal-type cells (HUVEC). |