Size-Dependent Antioxidant Effects of Gold Nanocrystalline Films

The exceptional chemical and physical properties of gold nanoparticles (AuNPs) have led to their significant use in both medicinal and cosmetic applications. This study investigated the antioxidant properties of AuNPs. Various sizes of AuNPs were synthesized through the electrodeposition technique, resulting in the formation of deposited films. Structural analysis with an X-ray diffractometer (XRD) revealed that a face-centered cubic structure of metallic gold with fine crystallite size (19 to 31 nm) was successfully formed on the substrate. Morphological studies employing a field emission scanning electron microscope (FESEM) showed that the deposited film consisted of relatively fine particles, providing numerous active sites for the radical scavenging mechanism. Antioxidant assays demonstrated that the deposited film exhibited promising antioxidant activity, particularly with a large number of very fine gold particles. This efficacy was evidenced by their efficacy in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, with a maximum percentage inhibition of 43.91%, and the Ferric Reducing Antioxidant Power (FRAP) assay, with a maximum percentage reduction of 38.22%. These results highlight the notable antioxidative capabilities of AuNPs, especially those produced under specific experimental conditions. This suggests their potential in tackling problems related to oxidative stress.