Wireless Millirobots Navigate Hard-to-Reach Blood Vessels With Precision, Revolutionize Clot Removal and Vascular Surgery

A team of researchers have successfully navigated wireless millirobots through a detached aorta, making a significant breakthrough in vascular surgery.

Challenges in Clot Removal

Blood clots are the body's way of preventing a person from bleeding too much. A type of blood cells called platelets work with plasma to create a clot over any injury. Once the injury is healed, the body is supposed to break down the clot.

Blood clots are healthy and lifesaving when they help stop bleeding. However, there are cases when they form when they are not needed, causing stroke, heart attack, and other serious medical problems.

Every year, millions of people around the world suffer from serious medical conditions caused by blood clots. According to the National Blood Clot Alliance, about 100,000 to 300,000 deaths from blood clots occur annually. This number is higher than the total number of people who die from breast cancer, AIDS, and vehicle crashes combined.

Conventional treatment methods involve the use of flexible instruments to remove blood clots and restore blood flow. In a procedure called mechanical thrombectomy, the surgeon introduces special devices through catheters which can either macerate or suction out clots. There is also surgical thrombectomy where an incision is made to get to the blocked blood vessel to remove the clot.

Thrombectomy is effective in reducing the risk of severe disability, loss of limb, or even death. It can also limit the damage and loss of bodily functions by restoring blood flow as quickly as possible.

However, some regions in the body pose challenges for surgeons because of their inaccessibility. Thrombectomy also carries some risks such as hematomas, blood vessel damage, infection, and recurrence of blood clot.

Miniature Marvels

At the University of Twente and Radbound University Medical Center, scientists have successfully navigated wireless millirobot through a detached aorta. The 3D-printed millirobots are screw-shaped devices containing a one-millimeter-long, one-millimeter-diameter permanent magnet.

The millirobots are equipped with corkscrew-shaped bodies which have the ability to travel along and against the arterial flow. As functionalized spiral-rolling devices, they are designed for upstream swimming in blood vessels.

The success of this groundbreaking technology lies in the synergistic collaboration of different departments at the Technical Medical Centre of the University of Twente. According to lead researchers Dr. Islam Khalil, the innovation required an interdisciplinary approach of the Robotics Lab, Blood Lab, LipoCoat, Laboratory of Biointerface, DesignLab, and MESA+. The team worked together to successfully test the millirobot in an ex vivo aorta model.

In this research, the experts used a robotically controlled rotating magnetic field in controlling the device wirelessly. An X-ray machine was used to precisely localize the millirobot while navigating through the aorta. The team maintained a maximum arterial flow of 120 mL per minute to demonstrate its stability in performing straight runs with and against the blood flow.

Based on the result of the tests, it was found that the robots, each with a tiny permanent magnet, can swim against the flow and drill through blood clots. This allows them to serve as microcatheters for diverse minimally invasive endovascular operations.