Tunable Film Density of Electrodeposited Gold Nanoparticles for Enhanced Antioxidant Activity

The synthesis of gold nanoparticles (AuNPs) is a critical aspect in the development of large-scale antioxidant nanomaterials. Although, biological methods offer a non-toxic reagent and an environmentally friendly route for synthesis. However, their scalability is limited by the non-uniformity of particle size, the scarcity of biological materials, the challenges associated with controlling organism growth, and the relatively long synthesis time. Therefore, chemical methods, especially electrodepositions, are preferred due to their effectiveness, efficiency, and the ability to precisely control particle size and shape through electrolyte modifications. In this study, two supporting electrolytes, KCl and Na₂SO₄, were employed. The results demonstrated that the type of electrolyte ion significantly influences the particle density of the AuNPs, with KCl electrolyte providing a higher particle density. This increased particle density correlates with a larger active surface area per unit area, subsequently enhancing the antioxidant activity of the AuNPs, as evidenced by up to 57% DPPH inhibition. Furthermore, cytotoxicity and cytoprotective assays indicated good biocompatibility and protective capabilities of AuNPs.