Green synthesis of gold nanostructures using pear extract as effective reducing and coordinating agent

Biosynthesis of gold nanoparticles and nanoplates (GNPs) was accomplished using aqueous fractions of pear extract as a safe, reducing, particle-stabilizing, and shape-directing agent. The maximum yields of spherical gold nanoparticles having the average sizes of 40, 20, and 10 nm were achieved at 30, 60, and 90 °C, respectively, at a pear extract concentration of 45% (v/v). The maximum yield of gold nanoplates was obtained with sizes ranging from 20 to 400 nm, particularly at reaction temperatures of 30, 60, and 90 °C, at a pear extract concentration of 5% (v/v). The surface chemistry analysis of the GNPs suggests that the sugars and peptides or proteins as key biomolecules of the pear extract play a crucial role in the reduction of Au(III), subsequently resulting in healthy capping. Therefore, this environmentally friendly synthesis method of GNPs for the particular type of morphologies is expected to be a competitive alternative to existing physical and chemical methods.