Abstract

EDIBLE PLANT MEDIATED BIOSYNTHESIS OF SILVER AND GOLD NANOFLAKES AGAINST HUMAN PATHOGENS

M. Koperuncholan* and M. Manogaran

Abstract

The biosynthesis of nanoflakes is in the modern nanotechnology. Biosynthesis of nanoflakes by plant extracts is currently under exploitation. Not only could silver and gold nanoflakes ranging from 90 to 40 nm in size be fabricated, but also spherical shape silver nanoflakes or rod, triangular, oval and circle sheped shaped gold nanoflakes could be easily modulated by reacting the biomass of Piper nigrum leaf with aqueous silver or gold precursors at ambient temperature. The marked difference of shape control between gold and silver nanoflakes was attributed to the comparative advantage of protective biomolecules and reductive biomolecules. The polychlorinated compounds and the water-soluble heterocyclic components were mainly responsible for the reduction of silver ions or chloroaurate ions and the stabilization of the nanoflakes, respectively. The antimicrobial effect of silver and gold nanoflakes were compared with positive control based on inhibition zone in disk diffusion tests microbial sensitivity to nanoflakes were found to vary depending on the microbial species. All the microbial strains depict higher sensitivity to the higher concentration (30 μL) for the test sample when compared to the positive control except B3, B4 and B6. The higher (30 μL/disc) concentration of sample got greater sensitivity than (15 μL/disc) lower concentration in all the tested microorganisms. The P. nigrum leaf in this work was very suitable for simple synthesis of nanoflakes.

Keywords: P. nigrum, Green Synthesis, Nanoflakes, Disc diffusion, Antimicrobial activity.