Copper doped magnetic vortex nanoring based nanotherapeutics for bacterial infection tri-therapy: interplay of magnetic hyperthermia, chemodynamic therapy and photothermal therapy†

Abstract

Infectious bacteria pose an increasing threat to public health, and hospital-acquired bacterial infections remain a significant challenge for wound healing. In this study, we developed an advanced nanoplatform utilizing copper doped magnetic vortex nanoring coated with polydopamine (Cu–MVNp) based nanotherapeutics for bacterial infection tri-therapy. This multifunctional nanoplatform exhibits remarkable dual-stimulus thermogenic capabilities and Fenton-like peroxidase activity. Exposure to an alternating magnetic field (AMF) and near-infrared (NIR) light allows the nanoring to elevate environmental temperatures through hysteresis losses and the non-radiative decay effects of the PDA coating. At a concentration of 150 μg mL⁻¹, Cu–MVNp increases the temperature by 18.2 °C under an AMF, achieving a specific absorption rate (SAR) of 640.9 W g⁻¹. On the other hand, under 808 nm NIR irradiation, the temperature rises by 42.6 °C, with a photothermal conversion efficiency of 46.45%. Furthermore, by incorporating copper ions (Cu), which can damage cell membranes themselves, Cu–MVNp was endowed with Fenton-like functions and can catalyze the formation of hydroxyl radicals (˙OH) from low concentrations (1 mM) of hydrogen peroxide (H₂O₂), thus enhancing the effectiveness of chemodynamic therapy (CDT). Cu–MVNp exhibits significant antibacterial efficacy, achieving notable kill rates against E. coli and S. aureus, with enhanced effects under NIR and nearly complete eradication with an AMF. In vivo tests using a mouse wound model confirm its potent bactericidal properties and good biocompatibility. The Cu–MVNp nanoring shows promise as an antibacterial treatment, potentially effective at inhibiting bacterial growth.