Dual-modality self-heating and antibacterial polymer-coated nanoparticles for magnetic hyperthermia

• Synthesized bi-functional self-heating and antibacterial magnetite nanoparticles
• Quantified antibacterial activity of MNPs against biofilms of S. aureus, as well as single cells
• The nanoparticles have high measured SAR and are effective for heat-generation in alternating magnetic fields.

Multifunctional nanoparticles for magnetic hyperthermia which simultaneously display antibacterial properties promise to decrease bacterial infections co-localized with cancers. Current methods synthesize such particles by multi-step procedures, and systematic comparisons of antibacterial properties between coatings, as well as measurements of specific absorption rate (SAR) during magnetic hyperthermia are lacking. Here we report the novel simple method for synthesis of magnetic nanoparticles with shells of oleic acid (OA), polyethyleneimine (PEI) and polyethyleneimine-methyl cellulose (PEI-mC). We compare their antibacterial properties against single gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria as well as biofilms. Magnetite nanoparticles (MNPs) with PEI-methyl cellulose were found to be most effective against both S. aureus and E. coli with concentration for 10% growth inhibition (EC10) of < 150 mg/l. All the particles have high SAR and are effective for heat-generation in alternating magnetic fields.