Sustainable and Efficacy Approach of Green Synthesized Cobalt Oxide (Co(3)O(4)) Nanoparticles and Evaluation of Their Cytotoxicity Activity on Cancerous Cells

In this study, rosemary leaf extract was effectively used to synthesize cobalt oxide nanoparticles (Co(3)O(4) NPs) using a rapid, low-cost, and environmentally friendly approach. The prepared Co(3)O(4) NPs were examined using various analytical techniques. However, UV spectrum analysis displayed two sharp absorption peaks at ~350 and 745 nm. The dynamic light scattering and zeta potential measurements were used to evaluate the particle size and the effective stabilization of the synthetic nanoparticles in the suspensions. A semi-triangular pyramidal shape of the Co(3)O(4) NPs with a wide particle-size distribution could be observed in the scanning electron microscopy images. The energy-dispersive X-ray spectrum confirmed their successful synthesis, as the experimental atomic percentages agreed with the theoretical values. Moreover, X-ray diffraction analysis revealed that the synthesized Co(3)O(4) NPs had a cubic crystalline structure corroborating that of theoretical Co(3)O(4). Additionally, the Co(3)O(4) NPs were not toxic at ≤62.5 µg/mL for Hep G2 and at ≤31.25 µg/mL for Mcf7. Therefore, these unique environmentally friendly Co(3)O(4) NPs at this safe concentration could be studied in the future for their therapeutic activity.