Green Synthesis and Antibacterial Activity of Fittonia albivenis-Mediated CuO–Ag Nanoparticles
Abstract
Multidrug-resistant Escherichia coli remains a major therapeutic challenge because conventional antibiotics are increasingly compromised by resistance mechanisms and restricted penetration into bacterial cells. This study evaluated Fittonia albivenis methanolic leaf extract as a reducing, chelating, and capping agent for the green synthesis of CuO–Ag bimetallic nanoparticles. Sequential Soxhlet extraction was performed using petroleum ether, ethyl acetate, and methanol, and the methanolic fraction showed the highest extraction yield and the greatest phenolic and flavonoid contents. CuO–Ag nanoparticles were synthesized at Cu:Ag molar ratios of 1:1, 1:2, and 2:1 and were characterized by UV–Visible spectroscopy, FTIR, dynamic light scattering, zeta-potential analysis, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The Cu:Ag 1:2 formulation exhibited the most favorable properties, with a hydrodynamic diameter of 31.6 ± 3.7 nm, a PDI of 0.21 ± 0.02, and a zeta potential of −36.8 ± 2.1 mV. XRD confirmed monoclinic CuO and face-centred cubic silver phases, while TEM showed particles predominantly within 24–36 nm. Antibacterial activity was assessed against E. coli MTCC 723 and MTCC 40. The optimized formulation produced inhibition zones of 25.8 ± 0.6 and 22.6 ± 0.5 mm, respectively. MIC/MBC values were 32/64 µg/mL for MTCC 723 and 64/128 µg/mL for MTCC 40. The results demonstrated that Fittonia-mediated CuO–Ag nanoparticles possessed stable physicochemical properties and strong bactericidal activity against both strains. Their enhanced performance over monometallic controls was attributed to complementary ROS generation, metal-ion release, membrane disruption, and inhibition of essential bacterial enzymes.
How to Cite
Preet Bansal, Neeraj Sethi, "Green Synthesis and Antibacterial Activity of Fittonia albivenis-Mediated CuO–Ag Nanoparticles", Vol. 2, Issue 12, 29-03-2025, pp. 21-34. DOI: 10.5281/zenodo.21821192
