Rough surface NiFe2O4@Au/Polydopamine with a magnetic field enhanced photothermal antibacterial effect

Infectious diseases caused by drug-resistant bacteria bring an increasing threat to public health. Thus, finding an effective approach equipped with a synergistic antibacterial performance becomes a critical challenge. This work reports a NiFe2O4@Au/Polydopamine core/shell nanosphere with rough surface, which exhibits a photothermal and magnetolytic coupling antibacterial behavior. The Au/Polydopamine (Au/PDA) hybrid layer, covered on the stable magnetic NiFe2O4 nanosphere by a one-step polymerization method, possesses an excellent photothermal effect. Simultaneously, the superparamagnetic characteristic offers the NiFe2O4@Au/Polydopamine with fantastic magnetolytic force to the biological organism under a rotating external magnetic field. It is found that the NiFe2O4@Au/PDA core/shell nanospheres show good photothermal antibacterial performance (808 nm laser irradiation) on both Escherichia coli and Staphylococcus aureus. Notably, the photothermal antibacterial performance can be significantly improved under applying the rotating magnetic field. This novel photothermal-magnetolytic coupled antimicrobial method supplies a high performance photothermal bactericidal therapy via a remote conduction and reduces the possible damage to normal tissue caused by overheating. Besides bactericidal therapy, the easily and scalable magnetolytic enhancing method is believed to possess high potential in drug delivery, antitumor, and bioseparation.