Biogenic Synthesis and Characterization of Silver Nanoparticles Using a Combined Leaf Extract for Anti-Bacterial and Biofilm Inhibition Properties

The environmentally friendly production of silver nanoparticles (AgNPs) involves using plant material to develop biocompatible antibacterial substances, presenting sustainable substitutes for harmful chemicals. This study aimed to optimize the green synthesis of AgNPs utilizing leaf extracts from Raphanus sativus, Ipomoea batatas, and Ananas comosus. Various characterization techniques employed for the synthesized nanoparticles included UV–Visible spectrophotometry, FTIR (Fourier Transform Infrared) spectrophotometry, XRD (X-ray Diffraction), SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), and DLS (Dynamic Light Scattering). The antibacterial and antibiofilm properties of nanoparticles were screened.  A noticeable color change confirmed the formation of nanoparticles. The UV–visible spectrophotometer displayed an absorbance peak at 450 nm. FTIR analysis identified the compounds that facilitated the reduction of silver ions, with functional groups such as OH, C-H, CHO, and N-H being detected. The DLS analysis indicated a zeta potential of -25.1 mV and a zeta average size of 62.44 d.nm. SEM examination revealed the silver nanoparticles as rod-shaped, measuring between 73.13 and 84.85 nm, while TEM showed spherical morphologies with an approximate size of 5 nm. The silver nanoparticles exhibited antibacterial properties against four gram-negative bacteria. Among them, AgNPs yield the highest zone of inhibition against Pseudomonas aeruginosa. The biofilm inhibitory capabilities of the biologically synthesized silver nanoparticles were assessed using Congo Red Agar, which provided qualitative results, and the microtiter plate method, which supplied quantitative data against Pseudomonas aeruginosa, a planktonic organism. This study highlights the potential applications of silver nanoparticles in addressing microbial kinetics, underlining their antibacterial and anti-biofilm effectiveness.