A Tumbling Magnetic Microrobot System for Biomedical Applications.

Area of Science:

• Biomedical Engineering
• Robotics
• Materials Science

Background:

• Microrobots offer potential for minimally invasive biomedical applications.
• Precise control and real-time imaging are crucial for in vivo microrobot navigation.
• Biocompatibility and payload delivery efficiency are key considerations for clinical translation.

Purpose of the Study:

• To develop and characterize an untethered magnetic microrobot system for biomedical applications.
• To evaluate the microrobot's navigation capabilities in complex biological environments.
• To assess the system's biocompatibility and drug delivery potential.

Main Methods:

• Development of a tumbling magnetic microrobot actuated by a rotating permanent magnet.
• Implementation of a two-degree-of-freedom magnet control for 2D steering.
• Utilizing high-frequency ultrasound for real-time microrobot tracking.
• Conducting in vitro, ex vivo, and in vivo experiments in colonic models.
• Performing payload release studies and cytotoxicity assessments.

Main Results:

• The microrobot demonstrated end-over-end tumbling motion for net forward propulsion.
• Two-dimensional directional control was achieved, enabling steering along various trajectories.
• Successful navigation was shown in murine and porcine colon models under different conditions.
• Ultrasound imaging provided real-time position monitoring, even with optical occlusion.
• The microrobot released a fluorescein payload and exhibited no significant cytotoxicity.

Conclusions:

• The developed magnetic microrobot system is capable of controlled locomotion in biological tissues.
• The system shows promise for targeted drug delivery and other in vivo biomedical applications.
• The materials used are biocompatible, supporting the potential for clinical translation.