A biofabrication approach for controlled synthesis of silver nanoparticles with high catalytic and antibacterial activities

•Biomediated synthesis of Ag nanoparticles with controlled sizes is presented.•Tobacco mosaic virus (TMV) acts as an efficient sacrificial biomediator.•Ag particles show high catalytic activity for nitrophenol hydrogenation reaction.•TMV-mediated Ag nanoparticles have high antibacterial activities against E. coli. We report simple, facile and size-controllable synthesis of uniform Ag nanoparticles with tobacco mosaic virus (TMV) as a biomediator in the absence of external reducing agents. UV–vis and TEM analysis show that Ag nanoparticles with average diameter of 2, 4 and 9nm were obtained by simply tuning the ratio of TMV/Ag(NH3)2+. The Ag formation in the presence of TMV showed autocatalytic growth followed by coalescence. The as-prepared TMV-mediated Ag nanoparticles show substantially higher catalytic and antibacterial activities than previous results. For the 4-nitrophenol hydrogenation reaction, the rate constants per surface area for 2 and 9nm Ag nanoparticles were determined to be 0.64 and 1.2Lm−2s−1 respectively. Both Kirby–Bauer disk diffusion test and tube culture results demonstrate high antibacterial activity of TMV-mediated Ag particles against Escherichia coli, with minimal inhibition concentration (MIC) of 2.3 and 2.5ppm for 2 and 9nm Ag nanoparticles respectively. We expect that our biomediated Ag synthesis approach can be readily extended to other biomaterials and metal nanoparticle systems.