Magnetic nanoparticles modified with quaternarized N-halamine based polymer and their antibacterial properties.

We present a simple and facile approach for preparing antibacterial magnetic nanoparticles, which were modified with quaternarized N-halamine based cationic polymer (CPQN). The CPQN functionalized magnetic nanoparticles (MNPs-CPQN) were characterized by X-ray photoelectron spectra, Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, and thermogravimetric analysis. Antibacterial properties were investigated with Gram positive bacteria S. aureus and Gram negative bacteria E. coli. Antibacterial assessment showed that the MNPs-CPQN could eliminate nearly 100% of S. aureus and 99.9% of E. coli (10(7-8) CFU/mg nanoparticles) in 5 min, while the bactericide rate of quaternized N-halamine precursor based cationic polymer coated magnetic nanoparticles (MNPs-CPQNP) were 99.6 and 95.2%, respectively. The prepared nanoparticles exhibited a good response to an external magnetic field and had a saturation magnetization of 36.6 emu g(-1). On the basis of their excellent antibacterial properties and magnetic responsiveness, the MNPs-CPQN would be a promising antibacterial material for water disinfection.