Controllable biosynthesis of silver nanoparticles using actinobacterial strains

Abstract

We report the effect of various parameters, namely substrate concentration, time, pH and temperature, on the biosynthesis of silver nanoparticles (AgNPs) by using the extract of actinobacterial strains, which were isolated from the sediments of Lonar Crater Lake in India. It was found that the formation of AgNPs and its morphology depended on synthesis conditions. Visual observation of the reaction mixture, ultraviolet-vis spectroscopic analysis and mass of synthesized AgNPs indicated that 25°C, pH 7 and 3 days of incubation time were optimal for its efficient synthesis. The transmission electron microscopy (TEM) analysis revealed aggregation and irregular shape of AgNPs both at acidic pH and below 25°C. It was found that alkaline pH and temperature higher than optimal fostered the formation of nanoparticle aggregates. Based on the obtained results, it was concluded that the efficiency of biological synthesis by using actinobacteria as well as the size and shape of fabricated nanoparticles can be manipulated by controlled conditions of synthesis process. The use of desired nanoparticles increases its potential for medical applications.