In the present study, nickel oxide nanoparticles (NiO NPs) were evaluated as an antibacterial and anticancer agent. The nanoparticles of nikel oxide were synthesized using aloe vera leaves extract and characterized with AFM (showing an average diameter of 45.11 nm), XRD and FE-SEM analyses. Three different concentrations (125, 250 and 500 µg/ml) were prepared from the synthesized NiO NPs and investigated for their potential antibacterial activity against both Enterococcus faecalis (Gram-positive bacteria) and Acinobacter baumannii (Gram-negative bacteria). While cytotoxicity and apoptotic activity were measured on both MCF-7 and AMJ13 cancer cell lines by MTT and caspase-9 luminescence assays. The results showed that NiO NPs inhibit bacterial growth, as indicated by large inhibition zones against both tested bacteria, with all studied concentrations. Moreover, the results of cytotoxicity and caspase-9 activity assays were in concordance with those of antibacterial activity, showing high cytotoxicity and apoptotic effects against both of the studied cancer cell lines and with all the tested concentrations of NiO NPs. Both the antibacterial and anticancer activities of NiO NPs were dose-dependent.
