Investigation of antibacterial potential of CuO nanoparticles synthesised using Costus pictus leaf extract

Abstract

The current research explores the production of CuO nanoparticles (NPs) using leaf extract from Costus pictus, employing environmentally friendly synthesis techniques. X-ray diffraction (XRD) analysis confirmed the crystalline nature of the CuO NPs, with a crystallite size of 18.07 nm. UV–visible studies revealed an absorption peak at 297 nm. Using Fourier-transform infrared (FTIR) spectroscopy, absorption peaks within the wavelength range of 450–4000 cm−1 were identified to unveil the chemical composition of the NPs. Moreover, field emission scanning electron microscopy (FESEM) imaging displayed uniform and well-defined spherical morphology of the NPs, while TEM confirmed their size range to be 15–25 nm. Energy-dispersive spectroscopy (EDS) affirmed copper and oxygen presence, with homogeneous distribution confirmed by elemental maps. Zeta potential analysis revealed a value of −25.1 mV, indicating good stability due to the negative surface charge preventing aggregation. Dynamic Light Scattering (DLS) analysis showed an average particle size of 354.4 nm and a PDI of 0.379, indicating moderately uniform particles. Furthermore, the agar well diffusion method unveiled significant antibacterial activity against multiple strains, including S. aureus, S. mutans, P. aeruginosa, S. mutans and E. coli. Notably, CuO nanoparticles exhibited a substantial inhibition zone of 17.57 ± 0.58 mm against S. mutans, surpassing the 15 mm inhibition zone observed with ciprofloxacin. This study highlights CuO nanoparticle synthesis from Costus pictus leaves, revealing properties and potent antibacterial effects, opening avenues for catalysis, sensing, and biomedicine.