Application of by-products and waste in the synthesis of nanosilver particles

Extracts from strawberry and raspberry leaves, carrot pomace, and spent grains, were tested as bioreducing agents for the synthesis of nanosilver particles (AgNP). Based on UV vis spectra, the leaf extracts produced the most AgNP, carrot pomace was less effective, and spent grains did not produce AgNP. The dynamic light scattering method revealed that AgNP ranged from 1 to 92nm in size, and that over 80% of the particles were about 10nm. Energy dispersive X ray spectroscopy showed that elements that typically stabilize nanoparticles were present. The well diffusion method (nutrient agar medium) indicated that AgNP synthesized with raspberry leaf extract exerted strong bacteriostatic and bactericidal activity against Gram negative bacteria and weaker activity against Gram positive bacteria. Although further analysis is needed to determine the mechanism of their synthesis, the results of this study show that plant extract based synthesis can produce nanoparticles with controlled size and morphology.