Narrow Results

The bactericidal magnetic nanoparticles were prepared by modifying magnetic nanoparticles (MNPs) with $N$-halamine polymer coating and quaternary ammonium polymer coating via a two-step soap-free emulsion polymerization method. The success of the surface functionalization was confirmed by Fourier transform infrared (FT-IR), X-ray photoelectron spectra (XPS), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and zeta-potential measurement. The results of antibacterial tests showed that the functional MNPs exhibited excellent antibacterial efficiency against both Gram negative bacteria E. coli and Gram positive bacteria S. aureus. Meanwhile the nanoparticles could be removed easily from water by an external magnetic field after antibacterial tests.

Graphene, a single layer of two-dimensional carbon material, has attracted much attention due to its excellent comprehensive properties including high mechanical strength, antibacterial property, excellent thermal and electrical conductivities, high specific surface area, impermeability, etc. In this study, 3-epoxypropyl-5,5-dimethylhydantoin (GH), as a precursor of $N$-halamine, was synthesized and attached onto graphene oxide (GO) for enhanced antibacterial activity. The synthesized GO–GH was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). After chlorination treatment by household bleach solution, the chlorinated graphene oxide-3-epoxypropyl-5,5-dimethylhydantoin (GO–GH–Cl) possessed great antibacterial efficacy. The synthesized GO–GH–Cl was added to chitosan (CS) solution to produce GO–GH–Cl/CS hybrid films via a solution casting method. The as-prepared antimicrobial hybrid films showed excellent antibacterial activity and could kill 100% of S. aureus and 100% of E. coli O157:H7 within 10min and 30min of contact time, respectively.