Antibacterial activity and cytotoxicity of novel silkworm-like nisin@PEGylated MoS.

Recently, molybdenum disulfide functionalized with poly-ethylene glycol (PEGylated MoS) has been widely used as a new drug delivery vehicle in biomedical field. However, the weak antibacterial activity of PEGylated MoS limits its application as an antibacterial agent. In this work, a novel silkworm-like conjugate of nisin loaded PEGylated MoS (nisin@PEGylated MoS) was developed for antibacterial application. The morphology and structure of PEGylated MoS were strongly dependent on the Mo/S molar ratio of precursors during the solvothermal process. The silkworm-like skeleton was well kept after loading with nisin. A high level of reactive oxygen species (ROS) induced by the conjugate was an important cause of bacteria death. Due to the different structure of cell membranes, the sharp edges could more easily puncture into Escherichia coli (E. coli) as compared with Staphylococcus aureus (S. aureus) and produced more intracellular ROS, which improved the antibacterial activity of nisin against E. coli. As a result, nisin@PEGylated MoS displayed the antibacterial activity against both gram-positive and gram-negative bacteria. Furthermore, the toxicity of the conjugate was very low. Therefore, the target conjugate of nisin@PEGylated MoS may have great potential application as an antibacterial agent.