Green reduction of silver ions to silver nanoparticles using aqueous plant extracts

Silver nanoparticles are used in numerous scientific fields due to their versatile properties and because their surface can be functionalized with different biological molecules. Their synthesis follows both conventional and unconventional routes and, in recent years, the methods that start from plants are constantly detaching from the hazardous, time consuming chemical methods. This paper presents the green synthesis of silver nanoparticles from St. Benedict's herb (Geum urbanum) and its corresponding aqueous extracts via two different temperature conditions: room temperature, for 24 hours with no additional stirring and 50⁰C, for 30 minutes under a cosntant stirring of 600 rpm. Silver nanoparticles were then characterized using UV-Vis spectroscopy at well - established time intervals in the range of 250 -650 nm and FTIR spectra were recorded to show the presence of different functional groups. DLS technique was used to investigate the particle size and zeta potential was also measured to analyze the stability of the green synthesized silver nanoparticles. TEM miscroscopy revealed a spherical - shape profile of the green synthesized silver nanoparticles and optical microscopy images were also recorded. Also, the antioxidant activity was determined using the DPPH method and compared to that of the crude aqueous extracts.