Synergistic microwave hyperthermia treatment for subcutaneous deep in situ breast cancer using conformal array antennas and a microwave-thermal-sensitive nanomaterial†

Abstract

When microwave hyperthermia (MWH) array antenna technology is used to treat breast cancer, how to effectively target and heat deep tumors and reduce thermal damage to healthy tissues is still a challenge in clinical applications. In this study, the synergistic MWH effect of conformal-array antennas (CAA) and a novel microwave-thermal-sensitive nanomaterial (MTSN) was investigated for the treatment of subcutaneous deep in situ breast cancer. At the beginning of the study, the thermal damage score was used to evaluate the therapeutic efficacy of the CAA. It was found that although array antenna technology can achieve effective heating of deep tumors, its damage to healthy tissues is unacceptable. Consequently, we developed a novel MTSN, ZIF-8@HA, whose unique structure significantly enhanced the absorption of MW energy and MW thermal conversion efficiency in the local tumor region. The MW thermal conversion efficiency of ZIF-8@HA achieved was as high as 46.46% in in vivo MW heating experiments. In the phantom that simulates the electromagnetic environment of the human body, the microwave-thermal sensitization (MTS) effect is also significant, and the reduction in the average thermal damage score of healthy tissues by more than 10% was verified through measurements using the coaxial probe method and COMSOL simulations. Cellular experiments confirmed that the combination of ZIF-8@HA and MW irradiation could significantly reduce the survival rate of tumor cells. In addition, cross-tissue MW heating experiments revealed the advantages of ZIF-8@HA combined with the CAA. Finally, phantom experiments confirmed that the synergistic use of the CAA with ZIF-8@HA significantly accelerated the local heating rate of deep tumors, reduced the time required for the tumor region to achieve 100% thermal damage, and effectively minimized the thermal damage to healthy tissues.