Biosynthesis of silver nanoparticles using Poa bulbosa extract and their antibacterial activity

Plant tissues are regarded as rich sources of phytochemicals that can be used in the fabrication of nanometals. In this work, silver nanoparticles (AgNPs) are fabricated using an aqueous Poa bulbosa extract as an efficient reducing agent. The plasmon resonance peaks of the AgNPs recorded by UV-visible spectra during 25 min of the extract exposure to silver ions indicate a blue shift with the chemical reduction process. The FT-IR spectrum of the Poa bulbosa extract shows the presence of chemical bonds of biomolecules that are involved in the reduction of Ag+ ions to AgNPs. The crystallite and particle sizes of AgNPs are estimated as 45.04 +/- 13.6, 56.98 +/- 13.08 and 43.14 +/- 16.06 nm by XRD, SEM and TEM, respectively. DLS measurements showed a mean particle size of 119.26 +/- 26.2 nm and zeta potential of -69.53 mV for the AgNPs indicating a proper colloidal stability. The most pronounced inhibition zone of antibacterial activity is found to be against Salmonella typhimurium, which is mainly attributed to the cell wall structure of the Gram-negative strains. This is also demonstrated in the minimum inhibitory concentration (MIC) of 1.6 mu g/mL in case of S. typhimurium.