title: Killing mechanism of stable N-halamine cross-linked polymethacrylamide nanoparticles that selectively target bacteria.
abstract: Increased resistance of bacteria to disinfection and antimicrobial treatment poses a serious public health threat worldwide. This has prompted the search for agents that can inhibit both bacterial growth and withstand harsh conditions (e.g., high organic loads). In the current study, N-halamine-derivatized cross-linked polymethacrylamide nanoparticles (NPs) were synthesized by copolymerization of the monomer methacrylamide (MAA) and the cross-linker monomer N,N-methylenebis(acrylamide) (MBAA) and were subsequently loaded 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 nanostructures. Our findings provide insights into the mechanism of action of P(MAA-MBAA)-Cl NPs and demonstrate the superior efficacy of the NPs over bleach (i.e., stability, specificity, and targeting). This work underscores the potential of developing sustainable P(MAA-MBAA)-Cl NP-based devices for inhibiting bacterial colonization and growth.
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, ‡The Department of Chemistry, and §The Institute for Advanced Materials and Nanotechnology, Bar-Ilan University , Ramat-Gan 52900, Israel.
authors.forename: Michal
authors.initials: M
authors.lastname: Natan
authors.forename: Ori
authors.initials: O
authors.lastname: Gutman
authors.forename: Ronit
authors.initials: R
authors.lastname: Lavi
authors.forename: Shlomo
authors.initials: S
authors.lastname: Margel
authors.forename: Ehud
authors.initials: E
authors.lastname: Banin
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D045744:Cell Line, Tumor; D004355:Drug Stability; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry*; D018384:Oxidative Stress / Q000187:drug effects; D011108:Polymers / Q000737:chemistry* / Q000494:pharmacology*; D012973:Sodium Hypochlorite / Q000737:chemistry; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000178:Acrylamides; D000900:Anti-Bacterial Agents; D011108:Polymers; D012973:Sodium Hypochlorite; C045985:methacrylamide
keywords: antibacterial; bacteria; controlled release; nanoparticles; reactive oxygen species; stable; targeting