MRI-Powered Millirobots: the future of minimally invasive surgery?

Researchers at Harvard Medical School and University of Houston unveiled new technology that potentially uses magnetic energy.

Generated by magnetic resonance imaging (MRI) scanner that would navigates milli-sized robots throughout the body.

  1. Potential to deliver medical treatments or perform minimally invasive surgery
  2. Technology still in early stages

Researchers used hydrocephalus: An accumulation of fluid in the deep cavities of the brain as an example when presenting milli-robotic technology at International Conference on Robotics and Automation in Seattle last week.

Traditional brain surgery methods would require a surgeon to cut through patient’s skill.


Using an MRI scanner, researchers mapped routes on high-quality brain images. Hacked the scanner to harness MRI’s own magnetic field to push small robots. The team then demonstrated use of magnetic forces to activate needle-biopsy robots and walk the milli-robots around an MRI. .

Their approach involved:

  • Navigating individual milli-robots to a target location
  • Allowing them to self-assemble in a manner that focuses on stored magnetic potential energy as kinetic energy for tissue penetration

However, MRI scanners alone don’t produce enough force to pierce tissues or insert needles. Secret of milli-robots ability to maneuver comes from the principles inspired by the MRI technology.

Researchers demonstrated and MRI scanners ability to steer millirobots around the body but found that the scanner along lacked necessary force to power surgical tasks.

Developed milli-robots with same technology used to operate a toy called a Gauss gun

  1. Consists of several steel balls separated by strong magnets
  2. As each ball hits the next, the stored potential energy increases
  3. The final ball flies forward with greater speed than the initial ball

Principles were applied to milli-robot which travel to the surgical site unassembled. Components are made from high-impact plastic and small titanium rods with steel balls on each side.

First component is medical instrument: consists of an 18-gauge needle for drug delivery or membrane piercing. Final component operates at trigger. Main benefit of this research is that scientists can now create clinically relevant forces inside a standard MRI scanner using just the MRI magnetic field.