Abstract

GREEN SYNTHESIS, OPTIMIZATION, CHARACTERIZATION OF SILVER NANOPARTICLES USING CASUARINA EQUISETIFOLIA BARK EXTRACT AND ITS ASSAYS

Saranya V. T. K. and S. Uma Gowrie*

Abstract

Casuarina equisetifolia, an exotic tree species, which serves as store house of several potential phytoconstituents. The present study aims to explore the role of these potential biomolecules as an effective reducing and capping agent, in the synthesis of Silver nanoparticles using aqueous bark extract of Casuarina equisetifolia. Further, optimization of various parameters such as temperature, time, pH for incubation and stability was also standardized for enhanced synthesis of Silver nanoparticles. Characterization of the optimized silver nanoparticles were carried out by different methods such as UV-Vis spectroscopy, FTIR analysis TEM micrograph study and by X-ray diffraction. Thus the optimized condition for the effective synthesis of silver nanoparticles using aqueous bark extract of Casuarina equisetifolia revealed that the required temperature was 80·C, time for incubation was 20 mins at neutral pH, which was found stable for 30 days. FTIR study was carried out to identify the functional groups that were responsible for capping and stabilization of the synthesized silver nanoparticles. TEM result shows that the synthesized Silver nanoparticles were round in shape and the size varied between 20nm -24nm. The average crystalline size was found to be 74 Å using Scherrer’s formula. Maximum antibacterial activity of the biosynthesized silver nanoparticles was observed against Bacillus sp., staphylococcus and E.coli strains. Silver nanoparticles synthesized biogenically with the help of bark extract of Casuarina equisetifolia had positive implications on germination percentage, mean germination time and germination rate This biogenic silver nanoparticles effectively degrade the methylene blue dye, with the degradation percentage of 56.18% at the end of fifth hour. Thus the synthesized silver nanoparticles using aqueous bark extract proves to be an effective tool to control pathogenic bacterial strains, germination of seeds and degrade methylene blue efficiently.

Keywords: Casuarina equisetifolia, bark extract, optimization, temperature, pH, TEM.