Green biosynthesis of nanosilvers using aqueous extract from Orthosiphon stamineus leaves

Plant based biosynthesis of nanoparticles is a green chemistry methodology that has been claimed as a simple, cost effective and environmental friendly process, alternatively to the conventional methods (chemical and physical). Nanosilver (NS) synthesis by a biological route using Orthosiphon stamineus aqueous leaf extracts has been studied. The NSs were characterized using UV-vis spectroscopy, transmission electron microscopy (TEM) attached with scanning TEM (STEM) and energy-dispersive X-ray spectroscopy (EDX). NSs were formed when the colour of the liquid reaction changed from clear to brownish-yellow. The formation of the NS was confirmed by UV-vis spectroscopy analysis which the result of the spectra and absorbance peaks at 432 nm. TEM analysis revealed that NS formed has crystalline nature with spherical shape and the particle size was ranging from 2 to 47 nm. The presence of silver was confirmed by EDX analysis with the aid of STEM.