An environmentally friendly technique has been developed to produce metal nanoparticles using green synthesis methods. In this study, silver nanostructures were synthesized using different sugar substitutes and artificial sweeteners as green reducing agents in an aqueous solution at low temperature. The main ingredients (such as maltodextrin, sucrose, saccharin, and sucralose) of the artificial sweeteners acting as reducing agents were used to reduce Ag+ ions to Ag0. The pH of the solution was controlled during synthesis through the addition of sodium hydroxide (NaOH) to increase the strength of the reducing agents by converting nonreducing sugars to reducing ones and consequently increasing the rate of silver nanoparticle formation. The size and morphology of the synthesized nanostructures were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The formation of nanostructures during the course of the reactions was investigated by UV-visible (UV-vis) spectroscopy characterization of an aliquot of sample at specific intervals. The function of each artificial sweetener and corresponding ingredients as a reducing agent and capping agent was investigated by Fourier-transform infrared spectroscopy (FTIR) and mass spectrometry (MS).

Barley stripe mosaic virus (BSMV) has recently been proposed as an attractive biotemplate for direct metallic nanomaterial synthesis as it interacts with metal precursors through multiple mechanisms. These interactions more than double the coating capacity for metal and accelerate nanomaterial synthesis, reducing costs, while potentially offering economical synthesis pathways for a wider range of nanomaterials. However, these studies were only able to generate BSMV via plant production, which is not well suited to widescale industrial production and limits engineering of BSMV-templated material properties to protein mutations that maintain or enhance infectivity in plants. Here, BSMV virus-like particles (VLPs) are produced from bacteria for the first time by fusing the origin of assembly from tobacco mosaic virus (TMV) to the transcript encoding BSMV capsid protein. Purification of BSMV-VLPs produced from Escherichia coli results in nanorods that average 82 nm in length and 21 nm in diameter. We also demonstrate that these rodshaped BSMV-VLPs can be more rapidly coated with Pd metal than in planta-produced BSMV in the absence of an external reducing agent. This study creates an alternate platform for BSMV-VLP production and enables future engineering opportunities to tune nanomaterial properties through biotemplate design.