pH-DEPENDENT SYNTHESIS OF STABILIZED GOLD NANOPARTICLES USING ASCORBIC ACID.

The stabilization of gold nanoparticles solution synthesized using ascorbic acid at room temperature is examined in detail. It is found that gold nanoparticles (AuNPs) synthesized using ascorbic acid have a narrow size distribution (31 ± 5, 36 ± 6, and 40 ± 5 nm) and can be readily stabilized just by adjusting the initial pH conditions of the reaction solutions. Whilst the initial pH strongly affects the stability of particles, it has no effect on the size of stabilized particles. The particles are nearly spherical having size distribution effectively in the range of 30 nm to 40 nm. Through time dependent UV-Vis spectra studies we also hypothesize the pH dependent stabilization mechanism wherein a layer of adsorbed ionic complex over AuNPs slows down the aggregation of AuNPs. The information obtained in this study can be used to design in-situ controlled nanoparticle synthesis system especially within the biological cells. Moreover, the method is green and biologically acceptable as well. [ABSTRACT FROM AUTHOR]