Honey mediated green synthesis of gold nanoparticles

Bio-directed synthesis of nanoparticles is of interest to biologists, chemists and materials scientists alike, especially in light of efforts to find greener methods of inorganic material synthesis. Though the biosynthesis of gold nanoparticles has been carried out by several groups of scientists using plants, fungi and bacteria, so far there is no report on the use of natural honey--mankind's only sweetener for centuries--for the synthesis of nanoparticles. Here, it is a report on a greener synthesis of Au nanoparticles using honey as reducing and capping agents. By adjusting the concentrations of HAuCl(4) and honey in aqueous solutions, colloids having a larger propensity of either anisotropic or spherical nanocrystals could be obtained at room temperature. The nanoparticles obtained were characterized by UV-visible spectra, high-resolution TEM and XRD. The spherical particles obtained have a size approximately 15 nm as shown by XRD pattern and TEM image. The high crystallinity with fcc phase is evidenced by bright circular spots in SAED pattern and clear lattice fringes in the high-resolution TEM image. FTIR measurements were carried out to identify the possible biomolecules responsible for capping and efficient stabilization of the Au nanoparticles synthesized using honey. The carboxylic acid group vibrations and amide I and II bands indicate the binding of protein with Au surface through the amine group rather than the carboxyl group.