Sodium Borohydride and Essential Oils as Reducing Agents for the Chemically and Green Synthesis of Silver Nanoparticles: A Comparative Analysis

Abstract

Silver nanoparticles (Ag-NPs) have gained immense attention among the variety of metallicnanoparticles during the past decades. In addition to the distinctive optical and electrical properties,Ag-NPs have been particularly employed for their biocidal features in industrial products, especially inbiomedicine. Despite the wide range of studies and applications of Ag-NPs, yet serious limitationsremained unsolved such as environmental toxicity caused by the reaction byproducts. In the presentstudy, Ag-NPs synthesized by chemical synthesis as well by green synthesis method as a saferalternative considered as environmentally friendly, cost-effective and easy-to-handle. Sodiumborohydride (NaBH4) and the natural essential oils originating from rosemary (Rosmarinus officinalis)and grape seed (Vitis vinifera) were used as synthetic and bio-reducing agents, respectively.Ultraviolet-visible (UV-Vis) and X-ray Diffraction (XRD) spectroscopy analysis were performed,providing an insight into the composition of the Ag-NPs. Ultimately, the antimicrobial activity of thenanoparticles was tested on a gram-negative bacterium, Escherichia coli (E. coli). The results revealedthat Ag-NPs can be synthesized by a sustainable alternative method with the usage of essential oilsoriginating from rosemary and grape seed, and the resultant Ag-NPs exhibit enhanced the antimicrobialactivity compared to the ones synthesized by the chemical reduction method.