Interfacial and Defect Polarization Enhanced Microwave Noninvasive Therapy for <i>Staphylococcus aureus</i>-Infected Chronic Osteomyelitis.

Abstract

Chronic osteomyelitis (COM), is a long-term, constant, and intractable disease mostly induced by infection from the invasion of <i>Staphylococcus aureus</i> (<i>S. aureus</i>) into bone cells. Here, we describe a highly effective microwave (MW) therapeutic strategy for <i>S. aureus</i>-induced COM based on the <i>in situ</i> growth of interfacial oxygen vacancy-rich molybdenum disulfide (MoS₂)/titanium carbide (Ti₃C₂T_<i>x</i>) MXene with oxygen-deficient titanium dioxide (TiO_2-x) on Ti₃C₂T_<i>x</i> (labeled as HU-MoS₂/Ti₃C₂T_<i>x</i>) by producing reactive oxygen species (ROS) and heat. HU-MoS₂/Ti₃C₂T_<i>x</i> produced heat and ROS, which could effectively treat <i>S. aureus</i>-induced COM under MW irradiation. The underlying mechanism determined by density functional theory (DFT) and MW vector network analysis was that HU-MoS₂/Ti₃C₂T_<i>x</i> formed a high-energy local electric field under MW irradiation, consequently generating more high-energy free electrons to pass and move across the interface at a high speed and accelerate by the heterointerface, which enhanced the charge accumulation on both sides of the interface. Moreover, these charges were captured by the oxygen species adsorbed at the HU-MoS₂/Ti₃C₂T_<i>x</i> interface to produce ROS. MoS₂ facilitated multiple reflections and scattering of electromagnetic waves as well as enhanced impedance matching. Ti₃C₂T_<i>x</i> enhanced the conduction loss of electromagnetic waves, while functional groups induced dipole polarization to enhance attenuation of MW.