Metal Ion Coordination Improves Graphite Nitride Carbon Microwave Therapy in Antibacterial and Osteomyelitis Treatment

Abstract

The ability to effectively treat deep bacterial infections while promoting osteogenesis is the biggest treatment demand for diseases such as osteomyelitis. Microwave therapy is widely studied due to its remarkable ability to penetrate deep tissue. This paper focuses on the development of a microwave-responsive system, namely, a zinc ion (Zn²⁺ ) doped graphite carbon nitride (CN) system (BZCN), achieved through two high-temperature burning processes. By subjecting composite materials to microwave irradiation, an impressive 99.81% eradication of Staphylococcus aureus is observed within 15 min. Moreover, this treatment enhances the growth of bone marrow stromal cells. The Zn²⁺ doping effectively alters the electronic structure of CN, resulting in the generation of a substantial number of free electrons on the material's surface. Under microwave stimulation, sodium ions collide and ionize with the free electrons generated by BZCN, generating a large amount of energy, which reacts with water and oxygen, producing reactive oxygen species. In addition, Zn²⁺ doping improves the conductivity of CN and increases the number of unsaturated electrons. Under microwave irradiation, polar molecules undergo movement and generate frictional heat. Finally, the released Zn²⁺ promotes macrophages to polarize toward the M2 phenotype, which is beneficial for tibial repair.