Green Sonochemical Synthesis of Silver Nanoparticles Using Adansonia Digitata Leaves Extract and Evaluation of Their Antibacterial Potential

Abstract

Metal nanoparticles in the field of nanotechnology are of great interest to modern scientific research due to their size effects, medical uses and, catalytic, electronic and optical properties. Green synthesis of metal nanoparticles is a feasible alternative to chemical methods as it is environmentally friendly and cost effective. In continuation with our research on green synthesis of silver nanoparticles using Kenyan medicinal plants, we here report the synthesis of novel silver nanoparticles (AgNPs) on ultrasonic bath using Adansonia digitata leaves extracts and analysis of their antibacterial activity. The nanoparticles were characterized by UV-Vis, High Resolution Transmission Electron Microscopy (HRTEM), FTIR spectroscopy and Energy Dispersive X-ray (EDX). EDX analysis affirmed the nanoparticles were pure silver. Crystalline nature of the nanoparticles was confirmed by bright circular spots in the Selected Area Electron Diffraction (SAED) in HRTEM image. The AgNPs were spherical with an average size 13 nm. FTIR analysis showed strong –C=C- and –OH stretching bands due to compounds capping the nanoparticles. The synthesized AgNPs showed high inhibition zones of 17.1±0.130 mm towards Gram-negative bacteria E. coli and 12.9±0.082mm towards Gram positive bacteria S. aureus. The aqueous A. digitata extract had no effect on growth inhibition of test bacteria. The study showed that the silver nanoparticles synthesized from the plant’s leaves extract had antibacterial activity against both Gram negative and positive pathogenic bacteria. The nanoparticles can be utilized towards developing novel drugs useful in combating pathogens.