Chitosan/nanoclusters membrane-based sensors with antibacterial properties for rapid detection of bacterial viability and food preservation

Abstract

In this work, copper nanoclusters (CuNCs) with tiny particle sizes were successfully obtained by a template-assisted synthesis approach. The interfacial interaction energies of cysteine (Cys) and CuNCs were simulated and calculated by molecular dynamics using the Materials Studio program package, and the anchoring sites of Cys on CuNCs surface in aqueous solution were investigated in detail by adsorption modeling. Chitosan (CS), a natural polymer, was used as a confining agent to enhance the excellent peroxidase (POD)-like activity of CuNCs. Therefore, the composite can catalyze the decomposition of hydrogen peroxide (H2O2) to generate hydroxyl radical (·OH) and possess higher antibacterial activity. A broad-spectrum antibacterial system based on CS@CuNCs was established for E. coli and S. aureus, avoiding the harmful effects of high concentration of H2O2 on organisms. In addition, a cascade reaction with glucose oxidase (GOx) was established for the specific consumption of glucose by bacteria, and a method for the visual colorimetric detection of bacterial viability within 30 min was established. Finally, based on the polymer properties of CS, a cling wrap with antibacterial properties was also prepared for food preservation. In summary, this study provides innovative proposals for the application of CS/nanocluster composite in food packaging, food safety, and even bioengineering.