Eco-friendly approach in synthesis of silver nanoparticles and evaluation of optical, surface morphological and antimicrobial properties

Abstract

Manoevering of particles at nanoscale tends to gain unique properties for use in various applications, viz., nano-generators, drug delivery system, and medical imaging [ 1 , 2 , 3 , 4 ]. Their efficiency to improve solubility, half-life, and sustained release of drugs find its application more appropriate in drug delivery [ 5 ]. In the current situation, the nano-biotechnology is one among the most energetic platform, explore the contemporary substantial discipline where the plants and various plant products find an imperious use in the fabrication of nanoparticles [ 6 ]. As vast applications of nanomaterials in various fields such as electronic, magnetic, optoelectronics, and information storage are well established. Researchers have found the remarkable application of nanomaterial in the field of medicine such as antimicrobial activity. The existing drug of choice is now becoming a major threat across the globe leading to the emergence of drug-resistant microbes or superbugs challenging the survival of humans. Therefore, to counteract the situation, researchers are on the verge of finding an alternate drug [ 7 ]. One such strategy is by the use of metals such as copper, zinc, titanium, magnesium, gold, etc., which, in their nano-form, are considered to exhibit remarkable physical, chemical, and biological properties. To counterbalance the situation, antimicrobial properties of the metallic nanoparticles have been explored to contain resistant strains [ 8 ]. Amongst them, silver nanoparticles are found to exhibit unique properties such as conductivity, chemical stability, and catalytic and biological (antibacterial, antiviral, antifungal, and anti-inflammatory) activities [ 9 ]. Despite various other methods of synthesizing nanoparticles, the eco-benign approach has been the most sought after. Besides, microbial synthesis, plant product/phytochemical-mediated synthesis of nanoparticles has drawn much attention because of its availability, reproducibility, and reliability [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. This study reports on the eco-friendly green syntheses of silver nanoparticles (Ag NPs) using two plant extracts such as Alternanthera sessilis leaf and Oregano root extracts as a reduction agent. In our study, the role of the extracts in reducing Ag + to Ag 0 has been investigated through spectroscopic and microscopic analyses emphasizing the antibacterial efficacy. The schematic representation of Ag NPs extracted from plants, as shown in Fig. 1 .