Synthesis of nickel nanoparticles by chemical and green route and their comparison in respect to biological effect and toxicity

Recent reports demonstrated an increase in the synthesis of nanoparticles (NP) and its applications. The chemical preparation of NP may be harmful. Thus, in this study, the biological activity and toxicology of nickel nanoparticles (NiNP) synthesized through chemical and green routes were compared. Chemical synthesis of NiNP was mediated by polyethylene glycol and hydrazine hydrate as stabilizing and reducing agent, respectively. Desmodium gangeticum aqueous root extract was used to prepare NiNP without any stabilizing and reducing agent. Nickel nanoparticles synthesized by both methods were characterized (ultraviolet–visible spectroscopy, X-ray diffractrometry, Fourier transform infrared spectroscopy, zeta potential and vibrating sample magnetometer) and compared. There was no major significant difference in the nature of the NP prepared by both methods. However, green synthesized NiNP showed reduced size and better monodispersity compared to chemical synthesized one. Free radical scavenging activities and antibacterial activities of NiNP prepared by chemical and green route suggest that these NP, prepared by green route possess reliable antioxidant and antibacterial activity. Evaluation of toxicity in animal and cell line suggests that NiNP synthesized by green route are nontoxic.