Synergistic antimicrobial mechanisms of silver-doped zinc oxide for water treatment: a systematic review

Abstract

This systematic review provides an overview of the existing research on antimicrobial mechanisms of silver-doped zinc oxide nanocomposites (Ag/ZnO NCs). It reports the existing knowledge on the synergistic effect (relationship) between silver (Ag) and zinc oxide (ZnO) for its optimum application. The doping of Ag into the ZnO has been used to enhance its photocatalysis and antimicrobial performance by improving the generation of reactive oxygen species (ROS). The Ag/ZnO NCs’ microbial elimination can be done through generated ROS, metallic (Ag+ and Zn2+) ions, and direct attack by the nanoparticles (NPs). Unlike the summation of individual use outcomes, the antimicrobial results of Ag/ZnO create a synergetic effect. This brings the sustainable use of the materials by increasing their efficiency while lowering the amounts used. This article systematically reviews the antimicrobial mechanisms of Ag/ZnO against gram-negative and gram-positive bacteria. It further analyses the quantitative and qualitative synergism between Ag and ZnO when applied together as antimicrobial materials. This systematic review found Ag/ZnO as a potential microbial elimination agent. Many studies reported the chemical synthesis of Ag/ZnO, which might cause a yield of toxic nanomaterials. Further studies on biosynthesis are pivotal for the sustainable supply of safe, non-toxic materials aimed at drinking water treatment.