Synthesis of uniform and high-density silver nanoparticles by using Peltophorum pterocarpum plant extract

Biologically synthesized nanoparticles have been widely used in the field of medicine. In this present work stable colloidal silver nanoparticles are prepared by a simple cost-effective, facile, and ecofriendly synthesis method to avoid the use of toxic chemicals. Peltophorum pterocarpum (PP) plant extract was employed to serve as both reducing and capping agents in this reaction. The effect of different experimental parameters such as the concentration of silver ions, the dosage of the plant extract, temperature, and reaction time on the synthesis of nanoparticles were studied. The synthesized nanoparticles were characterized using ultraviolet-visible (UV-vis) spectroscopy, X-ray diffractometry (XRD), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FT-IR), which revealed the nature of the nanoparticles. The nanoparticles have different diameters ranging from 40 to 85 nm. By optimizing the experimental conditions, more uniform high-density nanoparticles can be achieved. The synthesized silver nanoparticles exhibit significant antibacterial activity on gram-positive Staphylococcus aureus. The silver nanoparticles prepared in this way are uniform and stable, which can be stored at room temperature for more than two months. (C) 2014 The Japan Society of Applied Physics