Reactive oxygen species (ROS) photogenerated by two-dimensional (2D) nanomaterials provide a means of delivering persistent antibacterial activity in fluid media. Semiconducting molybdenum disulfide (MoS2) nanosheets are an attractive option for exploiting such activity by using visible light. However, the tendency of MoS2 nanosheets in suspension to restack or otherwise aggregate remains a critical obstacle, as it results in the loss of the desired photoactivity. We report here the development of persistent antibacterial activity by successfully immobilizing MoS2 nanosheets within porous cross-linked polymer beads. The nanosheet-loaded beads demonstrate continuous antibacterial activity against model species under visible-light exposure. The bactericidal activity is associated with ROS-mediated oxidative organismal stress, as assessed through chemical methods using fluorescent probes and gene-level biological studies. The porous beads demonstrate an effective antifouling capability and were physically stable with sustained bactericidal activity at an average of 99% over 5 cycles. The ability to confer reusable, continuous antibacterial activity under visible-light illumination is attractive in the context of the development of sustainable solutions for photoinduced antibacterial materials.
Keywords: antibacterial effect; molybdenum disulfide (MoS2); polymer beads; reactive oxygen species (ROS); reusability; two-dimensional (2D) nanomaterial.