Plant-mediated synthesis of Silver nanoparticles by two species of Cynanchum L. (Apocynaceae): A comparative approach on its physical characteristics

The present study evaluates the biosynthesis of silver nanoparticles (SNPs) mediated by xerophytic plants, Cynanchum viminale and Cynanchum sarcomedium. The reaction between plant extracts and silver nitrate solution resulted in a yellowish brown/dark brown colored solution which suggests the formation of SNPs. Physical characteristics of synthesized SNPs were determined using UV-Vis spectral, Scanning electron microscopy (SEM) and Energy dispersion X-ray spectroscopy (EDAX) analyses. The UV-Vis spectrum showed a maximum absorbance of SNPs at 500 nm for SNPs synthesized by C. viminale whereas maximum absorbance of 1.87 was observed at 400 nm for C. sarcomedium. Agglomerated nanoparticles were synthesized by C. viminale with an average diameter of ~ 60-68 nm as depicted by SEM. Nearly spherical nanoparticles of average size of ~ 60-85 nm were obtained by C. sarcomedium extract. A strong signal of silver at 3 KeV was confirmed by EDAX analysis for SNPs produced by both plants. Thus, the present green synthesis offers a viable and an ecofriendly way of fabrication of benign SNPs without any huge inputs in terms of energy and waste.