Magnetic nanoparticles modified with quaternarized <i>N</i>-halamine based polymer and their antibacterial properties

<p>We present a simple and facile approach for preparing antibacterial magnetic nanoparticles, which were modified with quaternarized <i>N</i>-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 <i>S. aureus</i> and Gram negative bacteria <i>E. coli</i>. Antibacterial assessment showed that the MNPs-CPQN could eliminate nearly 100% of <i>S. aureus</i> and 99.9% of <i>E. coli</i> (10<sup>7-8</sup> CFU/mg nanoparticles) in 5 min, while the bactericide rate of quaternized <i>N</i>-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<sup>−1</sup>. On the basis of their excellent antibacterial properties and magnetic responsiveness, the MNPs-CPQN would be a promising antibacterial material for water disinfection.</p>