Bactericidal magnetic nanoparticles with iodine loaded on surface grafted poly(N-vinylpyrrolidone)

Bactericidal magnetic nanoparticles were prepared by complexing iodine with poly(N-vinylpyrrolidone) (PVP) grown at the surface of silica coated magnetic nanoparticles (MNPs) via surface-initiated atom transfer radical polymerization (SI-ATRP). Approximately, 10 mg of iodine could be loaded onto one gram of the PVP-grafted MNPs to form bactericidal MNPs@PVP-I. At a concentration of 5 g L , MNPs@PVP-I could achieve 100% bactericidal rate for both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus with a concentration of ∼1 × 10 CFU mL within 3 min. After being used for killing the bacteria in solution, the bactericidal rate of the MNPs@PVP-I decreased to