Green synthesis, characterization and antimicrobial activity of silver nanoparticles by using Adiantum capillus-veneris as a reducing agent

Green nanotechnology represents a recent advancement in nanoscience focusing on the biological synthesis of nanoparticles (NPs). This study utilized stem and leaf extracts from Adiantum, a medicinal plant, to reduce silver ions into silver nanoparticles (AgNPs). Green synthesis methods are considered non-toxic compared to conventional physical and chemical methods. The formation of AgNPs was monitored through color change and confirmed by UV–Vis spectroscopy. Various characterizations including Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were conducted. SEM analysis revealed that the particle size of AgNPs ranged from 40 to 80 nm, while XRD analysis indicated a particle size range of 14–18 nm. The antimicrobial activity of the synthesized NPs was evaluated, demonstrating significant toxicity against various bacterial strains. The highest inhibition zone of 18 mm was observed against E. coli (Gram-negative), followed by Staphylococcus aureus (17 mm), Salmonella enterica (15 mm), and Pseudomonas aeruginosa (08 mm), as well as considerable antioxidant activity against DPPH with 70% inhibition. Furthermore, the green synthesis method proved to be faster in production compared to chemical methods. These environmentally friendly NPs have potential applications in diverse fields including cosmetics, food, and medical industries.