Plant (Costus Pictus D. Don) Assisted Green Synthesis of Double Oxide Nanoparticles for Antibacterial Applications

The present study focuses on synthesising CuO-MgO, CuO-ZnO, and MgO-ZnO double oxide nanoparticles (NPs) using the Costus pictus (insulin plant), offering an eco-friendly and cost-effective method. Comprehensive characterisation of the synthesised NPs was performed, including UV-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) with energy-dispersive X-ray spectroscopy (EDS), elemental mapping, Brunauer-Emmett-Teller (BET) analysis, and measurement of Zeta potential. The UV-Vis studies verified NP absorption, while FTIR confirmed the presence of functional groups. XRD analysis validated nanoparticle purity and crystal structure, disclosing crystalline sizes of 19.59 nm (CuO-MgO), 27.59 nm (CuO-ZnO), and 30.04 nm (MgO-ZnO) using Debye-Scherrer's equation. SEM images visually confirmed sizes within the 50-200 nm range. BET analysis revealed specific surface areas (SSA) of 48.69 m(2)/g (CuO-MgO), 16.59 m(2)/g (CuO-ZnO), and 10.95 m(2)/g (MgO-ZnO). CuO-ZnO displayed the highest stability with a Zeta potential value of -22.0 mV. Moreover, the antibacterial activity of the NPs against S. mutans, E. coli, P. aeruginosa, and S. aureus was evaluated using the agar well diffusion method. The results indicated that CuO-MgO and CuO-ZnO exhibited enhanced antibacterial responses against P. aeruginosa (19.5 +/- 0.71 mm) and S. mutans (19.67 +/- 0.58 mm), respectively, potentially attributed to their significant surface areas. This study highlights the synthesis and potential of CuO-MgO, MgO-ZnO, and CuO-ZnO NPs as promising antibacterial agents for biomedical applications.