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

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 <i>E. coli</i> and <i>S. aureus</i>, with enhanced effects under NIR and nearly complete eradication with an AMF. <i>In vivo</i> 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.