Preparation of gold/ carboxymethyl chitosan nanoparticles by radiation technique for application as an antioxidant

Abstract

Gold nanoparticles (AuNPs) with the sizes of 5.2, 6.7 and 7.3 nm have been synthesised by γ-irradiation of Au³⁺ solutions with the corresponding concentrations of 0.25, 0.5 and 1.0mM using carboxylmethyl chitosan as stabiliser. The optical characteristics and particle sizes of AuNPs have been determined by UV-Vis spectra and TEM images respectively. The antioxidant activity of AuNPs has been investigated at the concentrations of 0.025mM and 0.5mM using ABTS scavenging activity. The results have shown that the higher concentration of AuNPs displays the stronger antioxidant activity and the faster reaction time. The highest antioxidant activity has been found at the concentration of 0.375mM within 2-3 minutes. The antioxidant activity of AuNPs increases by the increase of reaction time and is higher than that of ascosbic acid. Thus, gold/carboxymethyl chitosan nanoparticles prepared by γ-irradiation method can be potentially utilised for the production of antioxidant products in pharmaceutics, functional foods and cosmetics.