Abstract

Background: Bimetallic silver-gold nanoparticles (Ag/Au NPs) with different structures have recently gained scientific attention due to their new and superior properties in comparison with metallic NPs made from a single metal. Ag/Au NPs (alloy or core-shell structures) have been applied to several biomedical, technological, and environmental applications. The potential applications of Ag/Au NPs are widespread yet poorly investigated in comparison with monometallic NPs. Besides traditional chemical and physical routes to synthesize bimetallic Ag/Au NPs, biogenic protocols are considered cost-effective, simple, and environmentally friendly. Despite their simplicity, biogenic routes to synthesize Ag/Au NPs are less explored than traditional synthetic protocols.

Methods: In this context, we present a review and discuss recent progress in the preparation of bimetallic Ag/Au NPs with different morphologies, structures, and size distributions using biogenic synthetic protocols.

Results: Biogenic synthesis using plant extracts, algae, bacteria, fungi, and other biological agents are presented and discussed. The characterization and potential applications of biogenically synthesized Ag/Au NPs in the different areas of medicine and biological applications, such as antibacterial, anticandidal, anticancer, antidiabetes, and as sensors for clinical diagnosis are presented and discussed.

Conclusion: Finally, challenges and drawbacks in the biological routes for the preparation of Ag/Au NPs for industrial applications are also discussed.

Keywords: Biogenic synthesis, Ag/Au nanoparticles, Bimetallic nanoparticles, Green chemistry, Bionanotechnolgy, Noble nanoparticles.

Graphical Abstract