A novel and controllable cell-based microrobot in real vascular network for target tumor therapy

Magnetic microrobots can be propelled precisely and wirelessly in vivo using magnetic field for targeted drug delivery and early detection. They are promising for clinical trials since magnetic fields are capable of penetrating most materials with minimal interaction, and are nearly harmless to human beings. However, challenges like the biocompatibility, biodegradation and therapeutic effects of these robots must be resolved before this technique is allowed for preclinical development. In this study, we proposed a cell-robot based on macrophages for carrying drugs to kill tumors propelled by magnetic gradient-based pulling. A custom-designed system with strong gradient magnetic field system in three-dimensional (3D) space using the minimum number of coils is used for precise control of the cell-based microrobot. The cell-based microrobots were fabricated by assembling magnetic nanoparticles (Fe3O4), anti-cancer drugs (DOX) into macrophages for magnetic actuation and therapeutic effects. Vitro experiments show that cell-based microrobots can be accurately transported to the destination or approaching a targeted cancer cell. The magnetic nanoparticles have negligible effects on the cell-based microrobot and the organism, which makes the cell-based microrobot safe for in vivo experiments. The carried drugs in the cell-based microrobot can be released by the irradiation of the near-field infrared and kill the cancer cells. Further in vivo experiments prove that the cell-based microrobot can be transported to tumor area and release drugs to kill cancer effectively. The research provides biocompatible and biodegradable cell-based microrobots for early tumor prevention and targeted precision therapy.