Evaluation of antioxidant, antimicrobial, anti-inflammatory properties and cytotoxicity of copper-doped NiO nanoparticles synthesized using biomass extract

Biomass extract-mediated production of nanoparticles (NPs) is a beneficial substitute for the conventional approach because it is sustainable and inexpensive. This work reports on the preparation of nickel oxide NPs and copper-doped nickel oxide nanoparticles (Cu-doped-NiO NPs) through the precipitation method using Calotropis gigantea flower extract (CGFE) and the assessment of their bioactivities. Different techniques are employed to characterize the NiO NPs and Cu-doped-NiO NPs. X-ray diffraction shows that the NiO NPs are face-centered cubic with 27.3 nm average crystallite size, whereas the Cu-doped NiO NPs are between 18.8 and 43.3 nm. Microscopy images reveal that the NiO NPs and Cu-doped-NiO NPs have blunt needle-like shapes. X-ray photoelectron spectroscopy analysis ascertains the formation of the NiO and the successful doping of NiO with copper. Mass spectrometric analysis of the extract reveals the presence of various phytochemicals. The antioxidant property was evaluated by ABTS and DPPH assays. The CGFE-mediated NiO NPs are effective against Staphylococcus aureus and Escherichia coli, while copper doping improves the antibacterial properties at a concentration of 3 and 4 mg/mL. The antifungal activity of the Cu-doped NiO NPs lasts more than 90 h against C. albicans, while its potential starts to decline after 24 h against A. niger. The anti-inflammatory activity of the Cu-doped NiO NPs is 80.1 %. The Cu-doped NiO NPs show an IC₅₀ value of 125.9 ± 2.1 μg/mL against fibroblast cells. The outcomes implied that the biosynthesized Cu-doped-NiO NPs could actively be used as a potent antimicrobial, antioxidant, and anti-inflammatory agent.