Facile one-pot green synthesis, characterisation, and antibacterial activities of silver nanoparticles using Camellia chrysantha leaf extract

Abstract

Green synthesis is a promising strategy for addressing pathogenic microorganisms. This study investigated the green synthesis of silver nanoparticles using Camellia chrysantha leaf extract (CC-AgNPs) and evaluated their antibacterial efficacy in wound treatment. CC-AgNPs were synthesised with ultrasonic assistance at 37 kHz, employing 4 mM silver nitrate (AgNO₃), an extract-to-silver salt ratio of 1:10, a pH of 8, and a temperature of 60°C for 60 min. Characterisation revealed a spherical morphology with an average transmission electron microscopy diameter of 18.53±5.66 nm, hydrodynamic size of 46 nm, polydispersity index of 0.457, and zeta potential of -25.7 mV. X-ray diffraction and selected area electron diffraction analyses confirmed a face-centred cubic crystalline structure, while energy-dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy analyses indicated that plant-derived biomolecules facilitated the reduction and stabilisation of nanoparticles. The CC-AgNPs demonstrated strong antibacterial activity, achieving complete inhibition of Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213, and Pseudomonas aeruginosa ATCC 27853 at a 256-fold dilution within 24 h. These findings underscore the significant potential of C. chrysantha leaf extract-mediated green synthesis of AgNPs as novel antibacterial agents. The unique phytochemical composition of C. chrysantha leaves, combined with an ultrasonic-assisted green chemistry approach, supports its potential application in wound healing.