Magnetic Tweezers Make Robotic Surgery Safer and More Precise

By HospiMedica International staff writers
Posted on 27 Mar 2025

Image: The haptic device allows an operator to control how the microrobots move (Photo courtesy of SMU)

Microrobots are small-scale robots designed using nanotechnology, and they hold significant potential for various medical applications, including surgery, targeted drug delivery, and biopsy. However, due to concerns about safety and ethics, there has been an increasing interest in involving humans in controlling microrobotic systems. Now, a breakthrough involving magnetic tweezers could facilitate the use of "human-in-the-loop" microrobotic procedures. Researchers have developed a magnetic tweezer system that enables doctors to remotely perform precise, non-invasive medical procedures on patients using a microrobot. The system incorporates real-time feedback through a haptic device, which allows the operator to feel the forces acting on the microrobots as they move or interact with their surroundings.

Developed by researchers from Southern Methodist University (Dallas, TX, USA) and George Washington University (Washington, DC, USA), this magnetic tweezer system allows an operator to precisely manipulate microrobots in a liquid environment from considerable distances. The system works by generating magnetic fields using a specialized coil setup, which directs the movement of microrobots made from magnetic materials. Remarkably, the system is capable of controlling microrobots over distances of more than 1,300 miles, making it feasible to use for remote medical procedures. Integral to this system is a haptic device, which functions similarly to a joystick, enabling the operator to control the movement of the microrobots. As the microrobots move through the liquid or interact with objects, their movement is tracked through image processing. The image data is then used to reconstruct the environment in 3D, allowing the system to calculate the forces acting on the microrobots.

This information is then transmitted to the haptic device, enabling the operator to both feel and observe the environment in real time. To ensure stability and smooth motion, even in the presence of environmental disruptions, the system uses Time Domain Passivity Control, an innovative technique that continuously analyzes and manages energy flow. By combining precise magnetic control with haptic feedback, this magnetic tweezer system offers a hands-on approach to interacting with microrobots at the micro-scale. This technology could potentially revolutionize safe and precise drug delivery as well. Since the microrobots are controlled externally via magnetic fields, there is no need for invasive tools or procedures, allowing treatments to be delivered exactly where they are needed in a controlled, non-invasive manner. This reduces the risk of affecting surrounding healthy tissue, making the process safer for patients.

“By keeping the operator in control, the system ensures safer interactions, while also providing the precision needed for sensitive applications,” said SMU nanotechnology expert MinJun Kim, one of the creators of the device.