Synthesis and sonodynamic performance of spinel ferrites

Sonodynamic therapy has emerged as one of the most valuable treatment methods with low side effects and deep tissue penetration. As a representative inorganic sonosensitizer, spinel-type ferrites have many advantages such as high reactive oxygen species (ROS) production efficiency and stability. However, current studies have not explored how metal doping impacts the sonodynamic effect of spinel ferrites. Herein, we synthesized three kinds of spinel ferrite nanoparticles (ZnFe 2 O 4 , CoFe 2 O 4 , and MgFe 2 O 4 ) and systematically investigated their sonodynamic performance. It is shown that three spinel ferrites are capable of producing singlet oxygen under ultrasound irradiation. Hydrogen peroxide further enhances the production of singlet oxygen, increasing the production rate by 1.05–2.31 times. The simultaneous existence of Co 2+ /Co 3+ and Fe 2+ /Fe 3+ redox couples in CoFe 2 O 4 could convert more efficiently hydrogen peroxide into oxygen through catalytic reaction, providing more oxygen to promote singlet oxygen production. Thus, CoFe 2 O 4 exhibits higher production efficiency than ZnFe 2 O 4 and MgFe 2 O 4 . In vitro experiments demonstrate the good biocompatibility of CoFe 2 O 4 nanoparticles and high ability to effectively kill cancer cells under ultrasound irradiation. In addition, CoFe 2 O 4 shows good therapeutic efficacy in animal models of colon cancer. These findings highlight the great potential of ferrite sonosensitizer for cancer treatment.