Tumoral Nanovesicles-Loaded Magnetotactic Bacteria for Tumor-Targeted Therapy under a Swing Magnetic Field

Tumor heterogeneity poses numerous challenges for targeted drug therapy. Although tumor cell-derived nanovesicles (NVs) have emerged as an intriguing method for tumor targeting, how to exert the antitumor effect after targeting remains a key concern. Magnetotactic bacteria (MTB) synthesize chain-like magnetite (Fe3O4) crystals with inherent magnetic moments, which could generate significant torque under a desired magnetic field and move along the magnetic field using their own flagella. Herein, a composite of MTB AMB-1 and NVs was fabricated via electrostatic adsorption where AMB-1 could transport NVs to the tumor site by a guiding magnetic field, while NVs also assist AMB-1 in binding to tumor cells. Subsequently, under the influence of a swing magnetic field (sMF), MTB exert physical stimuli on the cells, inducing the changes of mitochondrial membrane potential and cellular reactive oxygen species (ROS). Finally, it is revealed that the NVs-loaded AMB-1 induced a decrease in cellular viability and significantly inhibited the growth of tumors in vivo under the sMF. Therefore, by remote control of the guidance and stimuli production, the NVs-loaded AMB-1 was highly promising to advance the development of targeted therapeutic strategies for tumors under the context of tumor heterogeneity.