Garima Narwal, Neha Verma, Gulab Singh and Poonam Sahjlan
Abstract
The synthesis of nanoparticles using plant-based materials is an eco-friendly approach. Copper nanoparticles derived from Callistemon viminalis were produced using this sustainable method and utilized for their antibacterial properties. The color change from green to brown indicated the successful formation of copper nanoparticles, further confirmed by UV-Spectrophotometer. UV-Vis spectrophotometry, FTIR and SEM were employed to characterize the green-synthesized CV-CuNPs. The particle size and shape of the CVCuNPs were confirmed through DLS and SEM analysis. The antibacterial activity of the nanoparticles against gram-positive and gram-negative bacteria was assessed using the agar disc diffusion method, with ciprofloxacin serving as the standard antibiotic for comparison. This study introduced an innovative biological green method for synthesizing copper nanoparticles using leaf extracts. Copper sulfate was reduced with Callistemon viminalis (Bottle Brush) leaf extract in double distilled water. SEM analysis revealed nanoparticles with sizes ranging from 15.1 to 38.5 nm with spherical shape. UV-Vis spectroscopy showed absorption peaks at 510, 240, and 290 nm within the 200-900 nm range. FTIR analysis identified a fingerprint stretching frequency at 3910.35 cm- ¹ corresponding to CuO and CuO vibrational modes. DLS measurements indicated particle sizes between 15 and 80 nm, with an average size of 24 nm. The nanoparticles were tested for antibacterial activity against P. aeruginosa, E. coli, B. subtilis, and S. aureus, demonstrating effective antibacterial properties against all tested pathogenic strains. The biologically synthesized copper nanoparticles exhibited enhanced antibacterial activity against both gram-positive and gram-negative bacteria. Nanoparticles produced using plant extracts offer a sustainable and eco-friendly alternative to conventional chemical and physical methods and hold potential for applications in various areas that involve contact with the human body.