ROS - Triggered antibacterial and photothermal cytotoxicity of phyto-engineered NiO nanoparticles in MG - 63 bone cancer cells

Abstract

NiO NPs were fabricated through an eco-friendly hydrothermal process utilizing Cissus Quadrangularis stem (CQS) extract functioning as a phytogenic reductant. GC-MS analysis of the extract unveiled a diverse array of bioactive compounds, with Trisphosphate emerging as the dominant constituent, presumed to play a central role in biogenic diminution throughout nanoparticles generation. Structural characterization by XRD confirmed the cubic crystalline phase of NiO with an average crystallite dimension of 22.54 nm. The reduced crystallite size in conjunction with an appreciable surface area of 59.09 m²/g provides a strong basis for their incredible antibacterial and anticancer efficacy. FTIR spectra evidenced the characteristic Ni–O stretching band along with auxiliary functional groups, validating the integration of phytochemicals in nanoparticles synthesis. UV-Vis spectroscopy revealed an absorption edge at 305 nm with a corresponding band gap of 3.65 eV, suggestive of their proficiency in ROS-mediated bioactivities. FESEM and HRTEM analyses displayed predominantly needle-like nanostructures, while EDS with elemental mapping affirmed their compositional purity. Functionally, NiO NPs demonstrated potent antibacterial action against B. subtilis, and CQS-derived NiO NPs exhibited efficient PCE under NIR irradiation, resulting in elevated intracellular ROS levels in MG-63 cells. The excessive ROS disrupted redox balance, inducing mitochondrial dysfunction and membrane depolarization. This ROS-driven photothermal stress ultimately initiated pronounced cancer cell death, highlighting their potential for bone cancer therapy. Collectively, these findings delineate the mechanistic framework underlying the dual antibacterial and anticancer efficacy of the synthesized NiO nanostructures, reinforcing their significance as advanced nano-engineered platforms for bone malignancy.