Synthesis of gold nano particles with enlargement size by gamma Co-60 irradiation and investigation of antioxidation effect

Abstract

Gold nanoparticles (AuNPs) with size in the range of 10-53 nm were synthesized by γCo-60 irradiation using water-soluble chitosan (WSC) as stabilizer and size enlargement by seed approach.  Absorption wavelength (λmax) was measured by UV-Vis spectroscopy and particle size was determined from TEM images. Results showed that value of λmax increased from 523 nm (seed particles) to 525, 537 and 549 nm and the size of AuNPs increased from 10 nm (seed particles) to 20, 38 and 53 nm, respectively for concentration ratio of Au3 +/ Au0 (seed)  of  2.5, 5 and 10. Antioxidant effect of AuNPS with size of 10, 20, 38 and 53 nm was investigated using free radical 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS• +). Results indicated that the smaller the particles size (10 nm) the stronger the antioxidant effect attained. Thus, AuNPs/WSC synthesis by γCo-60 irradiation are promising for applications as antioxidants in cosmetics and in other fields as well