RECHARGEABLE NANOPARTICLES FOR ANTIBIOFILM APPLICATIONS

The increased resistance of bacteria to antimicrobials and their ability to form biofilms poses a serious public health threat worldwide. This has prompted the search for new agents that can inhibit bacterial growth and surface colonziation while providing stable long lasting activity. In the current study, rechargable N-halamine-derivatized cross-linked polymethacrylamide nanoparticles (NPs) were synthesized by co-polymerization of the monomer methacrylamide (MAA) and the cross-linker monomer N,N-methylenebisacrylamide (MBAA). These NPs can be loaded and subsequently recharged with oxidative chlorine, using sodium hypochlorite (NaOCl). The chlorinated NPs demonstrated remarkable stability and durability to organic reagents and to repetitive bacterial loading cycles as compared with the common disinfectant NaOCl (bleach), which was extremely labile under these conditions. The antibacterial mechanism of the cross-linked P(MAA-MBAA)-Cl NPs was found to involve generation of reactive oxygen species (ROS) only upon exposure to organic media. Importantly, ROS were not generated upon suspension in water, revealing that the mode of action is target-specific. Further, a unique and specific interaction of the chlorinated NPs with Staphylococcus aureus was discovered, whereby these microorganisms were all specifically targeted and marked for destruction. This bacterial encircling was achieved without using a targeting module (e.g., an antibody or a ligand) and represents a highly beneficial, natural property of the P(MAA-MBAA)-Cl nano-structures. Finally, P(MAA-MBAA)-Cl NPs embedded within irrigation drippers were shown to prevent fouling compared with the control, hence providing the drippers with durable `self-cleaning` and `self-sterilizing` properties. In summary, our findings underscore the potential of developing rechargeable P(MAA-MBAA)-Cl NPs-based devices for inhibiting bacterial colonization and growth.