Microwave assisted green synthesis of silver nanoparticles using coleus amboinicus leaf extract

Abstract

Objective: Current study is aimed at the formulation of silver nanoparticles loaded with the extract of Coleus amboinicus leaf extract by microwave irradiation. A facile and green synthesis of silver nanoparticles by using a biological agent such as plant extracts with the aid of microwave irradiation is proposed as an economical and environmentally friendly approach alternative to chemical and physical methods. Methods: In order to fabricate silver nanoparticles by microwave irradiation, aqueous extract of leaves Coleus amboinicus (CA) were treated with aqueous silver nitrate solution and mixture was placed in the microwave oven for exposure to microwave. Optimizations of the process were carried out by varying the quantity of extract, silver nitrate concentration and duration of microwave irradiation. Formations of nanoparticles were confirmed by UV-visible spectroscopy observing for the presence of surface plasmon resonance (SPR) peak. Nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. Results: Silver nanoparticle showed the SPR optical absorption band peak at 434 nm by UV-Visible spectrophotometer. Reaction mixture containing 2 mmol silver nitrate and 9 ml of extract subjected to microwave irradiation of 60 sec at a temperature of 60 °C was found to be optimised condition, which produced nanoparticles that were spherical in shape and had an average diameter of 15.685 nm. Conclusion: This research study opens an innovative design to progress our understanding of how silver nanoparticles behave can be optimized to improve their surface morphology, which is beneficial to improve its therapeutic effect.