Designing Rechargeable N-halamine Nanoparticles for biofilm prevention

Biofilm formation is a serious problem in medical and industrial settings due to the increased resistance of these communities to killing compared to free-living bacteria. This has prompted the search for agents that can inhibit both bacterial growth and biofilm formation. In this study, N-halamine rechargeable nanoparticles (NPs) were synthesized by co-polymerization of the monomer methacrylamide and the cross-linker monomer N,N-methylenebisacrylamide, and were subsequently loaded with Cl⁺, using bleach. The chlorinated NPs demonstrated remarkable stability and durability to organic reagents and to repetitive bacterial loading cycles. The antibacterial mechanism of the P(MAA-MBAA)-Cl NPs involved generation of reactive oxygen species (ROS) only upon exposure to organic media, but not 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 aureusbacteria but not with human cells was discovered, whereby these microorganisms were all specifically targeted and marked for destruction. Finally, in collaboration with Netafim Ltd. irrigation drippers containing the P(MAA-MBAA)-Cl were incubated in the field and were shown to prevent fouling on them for 5 months compared with the control, hence providing the drippers with `self-cleaning` and `self-sterilizing` properties. Further, the NPs offer recharging to the surface, thus providing long-lasting protection that does not exist in the products available today. In summary, our findings underscore the potential of developing sustainable P(MAA-MBAA)-Cl NPs-based devices for inhibiting bacterial colonization and growth.