Enzyme–metal nanocomposites for antibacterial applications

Metal nanoparticles have been used as antibacterial agents widely, and the combined use of enzymes and metal nanoparticles promotes antibacterial activity, achieving a synergistic effect. Additionally, enzymes decrease the amounts of metals and increase biocompatibility, thereby reducing toxicity of metals. However, the efficiency of enzymes is hindered when coupled with metals, which causes deactivation in the function of enzymes. How can a balance be struck between metals and enzymes? Although the antibacterial mechanism of metal nanoparticles is relatively clear, how enzyme–metal nanocomposites work against bacteria is not conclusive. Here, we describe several examples on the synthesis of enzyme–metal nanocomposites via co-immobilization or in situ reduction and summarize how enzyme–metal nanocomposites combat microorganisms.