Magnetotactic bacteria-mediated integrated magnetic targeted hyperthermia for in-situ deep-seated tumor

Unlike hyperthermia after intratumoral injection, the method of integrated magnetic targeted hyperthermia (iMTH) guides magnetic medium to the target site and then directly performs in-situ heating, showing great potential for effective treatment of deep-seated tumors in the body. Magnetotactic bacteria (MTB), having chain-like arranged magnetic nanoparticles within its body and active movement along an external magnetic field, are considered as a very fitted material for iMTH. However, the amount of MTB concentrated on the deep-seated tumor posed a significant challenge for the successful implementation of iMTH. Herein, we aim to validate the strategy of integrating magnetic targeting and hyperthermia. An in-situ liver tumor model in mouse was developed as deep-seated tumors. After administering the polar MTB MO-1 intravenously via the tail vein, a focusing magnetic field navigated these bacteria to effectively accumulate at the deep-seated tumor site. Immediately afterwards, this targeted aggregation of MO-1 cells triggered a localized magnetic hyperthermia directly at the cancer site under an applied alternating magnetic field. Our findings demonstrated that this hyperthermia induced by the bacteria led to the death of liver cancer cells, thereby effectively curbing the progression and growth of the cancer. These promising results suggested that an iMTH approach was developed, harnessing the power of MTB. This method stands as an exciting and potential therapeutic strategy for the treatment of deep-seated tumors, offering new hope in the fight against cancer.