In vitro evaluation of cytotoxicity, possible alteration of apoptotic regulatory proteins, and antibacterial activity of synthesized copper oxide nanoparticles.

Copper oxide nanoparticles (CuO-NPs) were synthesized using a urea-based thermal decomposition technique, and characterized using different techniques. X-ray diffraction (XRD) and Raman spectroscopy confirmed the phase purity and crystalline structure of CuO-NPs. The size of CuO-NPs was investigated using XRD and was confirmed via dynamic light scattering analysis. CuO-NPs showed an average diameter of ∼20nm. The possible cytotoxicity of CuO-NPs was evaluated in HT-29 and SW620 cancer cell lines. The median inhibitory concentration of CuO-NPs in HT-29 and SW-620 cells was 4.99 and 3.75μg/mL, respectively. The underlying mechanism responsible for apoptosis in colon cancer cells after CuO-NP exposure has not been well understood. In this study, we investigated the possible mechanisms of induction of apoptosis via analysis of the expression of Bcl-2 and Bcl-xL proteins in HT-29 human colon cancer cells after CuO-NP exposure. Western blot assay showed downregulation of Bcl-2 and Bcl-xL protein expression after CuO-NP exposure. Our findings may aid in the understanding of the potential mechanisms responsible for induction of apoptosis owing to inhibition of Bcl-2 and Bcl-xL protein expression. Furthermore, the antibacterial activity assay showed that the synthesized CuO-NPs did not exert significant inhibitory effects against different gram-positive and gram-negative bacteria in vitro.