Fabrication of magnetic nanoparticles armed with quaternarized N-halamine polymers as recyclable antibacterial agents

Magnetic recyclable bactericidal nanocomposites (Fe₃O₄@PDMC) were well-designed and prepared by coating of Fe₃O₄ nanoparticles with quaternarized N-halamine polymers via the free radical polymerization process. In which, 5,5-dimethylhydantoinyl-(3-ethyl-methacrylamine)propyl dimethylammonium bromide (DEMPA), a new monomeric N-halamine precursor, was used as a coating material as well as the dual-functional bactericidal agent. The developed Fe₃O₄@PDMC nanocomposites exhibited suitable size and super-paramagnetic responsibility. The antibacterial results showed that the Fe₃O₄@PDMC nanocomposites had excellent biocidal abilities against Staphylococcus aureus (gram-positive) and Escherichia coli (gram-negative). Furthermore, the TTC (Triphenyl Tetrazolium Chloride)-dehydrogenase activity assay confirmed that the reductions of the bacteria were mainly attributed to powerful biocidal effects of the coating polymer instead of bacteria capture by the cationic surface. Interestingly, due to the magnetic responsive performance of Fe₃O₄, the as-prepared Fe₃O₄@PDMC nanocomposites can be recycled by a magnet and reused for antibacterium through the quenching/rechlorination procedure. All the results presented in this study show that the proposed Fe₃O₄@PDMC nanocomposites could be a competitive candidate for water purification systems and household sanitation.