Magnetic tentacle robot navigates smallest bronchial tubes

A magnetic tentacle robot could one day take tissue samples or deliver targeted cancer therapy to the tiniest bronchi in the lungs.

This is the claim of engineers, scientists and clinicians at the STORM lab at Leeds University who developed the proof-of-concept robot with a diameter of 2 mm.

The team is pioneering the use of robotic systems to aid in endoscopy and catheter procedures and their current findings are published in Soft robotics

The proof of concept was based on lab testing with a 3D replica of a bronchial tree modeled from anatomical data. The next phase of the study will examine the device’s effectiveness in navigating lungs taken from a cadaver.

Currently, doctors use a bronchoscope to examine the lungs and airways. The procedure involves passing a flexible tube-like instrument approximately 3.5 to 4 mm in diameter through the nose or mouth and into the bronchial passages.


Due to its size, the bronchoscope can only travel as far as the upper levels of the bronchial tree. From there, a catheter about 2 mm in diameter is passed through the bronchoscope and then into the smaller tubes of the lungs.

Doctors are limited in how to move a bronchoscope, making it difficult to navigate the instrument and catheter to where they are needed.

According to the University of Leeds, the magnetic tentacle robot has been developed to be much more agile and uses a robotic guidance system that is personalized for each procedure.

In a statement, Professor Pietro Valdastri, director of the STORM Lab that oversaw the research, said: “A 2mm magnetic tentacle robot or catheter, whose shape can be magnetically controlled to conform to the anatomy of the bronchi, can most areas of the lung, and would be an important clinical tool in the investigation and treatment of potential lung cancer and other lung diseases.

“Our system uses a self-contained magnetic guidance system that eliminates the need for patients to be X-rayed while the procedure is being performed.”

To develop the robotic system, the research team needed to create a device that was small, flexible and capable of navigating the anatomy of the bronchial tree. They then needed an autonomous system to guide the magnetic tentacle robot into place.

Magnetic Tentacle Robot
The image shows a life-size model of part of a bronchial tree constructed from anatomical data. Part of the magnetic tentacle robot can be seen on the right (Image: Leeds University)

To make the robot smaller while maintaining motion control, the researchers fabricated it from a series of interconnected cylindrical segments, each 2mm in diameter and about 80mm in length. The segments were made of a soft elastomeric material impregnated with magnetic particles.

The presence of the magnetic particles allows the interconnected segments to move somewhat independently under the influence of an external magnetic field. The result is a magnetic tentacle robot that is highly flexible, can change shape and is small enough to avoid clinging to anatomical structures in the lungs.

Magnets mounted on robotic arms on the outside of the patient would be used to guide the device into the lungs in a process that would be suitable for any procedure.

The route through the bronchial tree is planned based on preoperative scans of a patient’s lungs and programmed into the robotic system. As the magnets move outside the patient, they develop forces on the magnetic particles in the segments of the catheter, causing them to change shape or direction, allowing the robot to maneuver through the lungs and to a site of a suspicious lesion.

Once at the target site, the robot is used to take a tissue sample or deliver a treatment.

The team warns that it could be several years before the magnetic tentacle robot is rolled out in hospitals.

Abhishek Maheswari
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