Engineered Magnetobacterial Microrobots with Tunable Self-Mineralization for Precise Imaging-Guided Photothermal Therapy.

Abstract

Micro/nanomotors hold promise for remote manipulation in complex biological environments. However, integrating robust barrier penetration, real-time tracking, and effective theranostics within a motor system remains a formidable translational challenge. Here, we engineer sequential magneto-actuated and optically imageable biohybrid micromotors (BAMs) for precise tumor therapy. BAMs consist of two components, magnetospirillum bacteria (AMB-1), enabling autonomous tumor tropism via hypoxia-driven chemotaxis and magnetic navigation under external fields, and extracellularly biomineralized Ag₂S quantum dots, serving as near-infrared (NIR)-II fluorescence imaging agents and photothermal converters. <i>In vivo</i> studies demonstrate that BAMs can migrate to the hypoxic core of the tumors through the synergistic effect of hypoxia-targeting chemotaxis and magnetic actuation, which can be monitored via NIR-II fluorescence imaging. Moreover, as a photothermal therapeutic agent, BAMs effectively induce tumor cell apoptosis and suppress tumor growth through photothermal conversion. This innovative BAMs platform not only overcomes passive diffusion but also provides precise theranostics through integrated magnetic guidance, NIR-II imaging, and photothermal therapy, showcasing the promise of biohybrid systems.