Green synthesis of gold nanoparticles using ethanolic leaf extract of Centella asiatica

摘要

Here, we report a novel use of the ethanolic leaf extract of Centella asiatica to produce gold nanoparticles by reduction of AuCl_4~- ions. The phytochemicals present in the leaf extract served as effective reducing and capping agent. The gold nanoparticles obtained were characterized by UV-visible spectra, transmission electron microscopy (TEM) and X-ray diffraction (XRD). TEM studies showed the particles to be of various shapes and sizes. Selected-area electron diffraction (SAED) pattern and high-resolution TEM image confirmed a fee phase and high crystallinity of the particles. The XRD patterns showed a (111) preferential orientation of the gold nanoparticles. Fourier transform infra-red spectroscopy (FTIR) measurements showed the GNPs having a coating of phenolic compounds indicating a possible role of biomolecules responsible for capping and efficient stabilization of the gold nanoparticles. As no synthetic reagents were used in this method, the synthesized gold nanoparticles have potential for application in bio-molecular imaging and therapy.