Biofabrication and extraction of silver nanoparticles using leaf extract of azadirachta indica

Abstract

Development of reliable,economical and eco-friendly process for the synthesis of silver nanoparticles is a major step in the field of nanotechnology.There are various conventional approaches involving chemical methods, which are associated with environmental toxicity.Green synthesisapproach has emerged as an alternative method to the conventional approach, as it is more economical, biocompatible and environmentally benign. Monodisperse nanoparticles of size less than 100 nm are currently in demand for wide range of applications in different fields of industry. One of the steps to achieve this objective is to use natural reducing agents. This study manifests the synthesis of small sizedand stable silver nanoparticles using the plant extract of Azadirachtaindica.For detailed study of the morphology and structure of fabricated silver nanoparticles, characterization was done using UV-Vis,ATR-FTIR,DLS,ZETA and SEM. UV–visible spectrum of the aqueous solution containing silver nanoparticles showed a peak centred at 430 nm, and this is due to surface plasmon resonance of silver nanoparticles. SEM image exhibitedthe formation of well-dispersed and spherical shaped silver nanoparticle in the range of 50–100 nm.ATR-FTIR analysis confirmed the presence of significant amount of reducing entities.It further revealed that phytochemicals like flavanoids and terpenoids present in neemleaf extract were the main entities to stabilize the synthesized nanoparticles. The synthesized silver nanoparticles were isolated from aqueous solution containing silver nanoparticles using size exclusion chromatography(Sephadex G100). The purified silver nanoparticles were found to be more stable for longer period.