ITMO: Soft robot

2022: Soft Robot Presentation

Scientists at ITMO University have proposed treating thrombosis with soft robots controlled by a magnetic field. This method is safer than analogues - in the future it will reduce interventions in the body and "protect" the internal walls of the vessels from damage, which, in turn, will reduce the likelihood of the formation of new blood clots.

Thrombosis (the formation of dense blood clots in vessels that prevent normal blood movement) is one of the main causes of stroke and coronary heart disease. They treat it most often with surgery: they mechanically remove blood clots with special devices, for example, a catheter or stent. The invasive nature of this approach threatens human health: rigid devices that are made of plastic or metal can damage the internal walls of vessels, causing clots to re-form. Also, in some cases, thrombolytic therapy is used to treat thrombosis, but drugs can lead to severe bleeding.

ITMO scientists are working on a more gentle and effective method of removing blood clots - with the help of soft robots, the shape and movement of which are "programmed" by a magnetic field. This is a biocompatible elastomeric matrix with a thermosensitive polymer and embedded ferromagnetic particles.

We were looking for a way to reprogram the material so that it could move in the liquid. When this task was solved, we adapted it for the treatment of thrombosis. During the experiments, we managed to determine for our robots the optimal size, composition and design. Length and width - about 15 mm and 2 mm: such parameters allow them to move easily along deep veins. Robots are planned to be introduced into the vessel in the form of a soft strip, but under the influence of a rotating magnetic field they will be transformed into a spiral. This spiral 'picks up' to the thrombus and, like a kind of drill, 'twists' the clot. Having hooked it, it also returns under the influence of a magnetic field. Then it remains only to remove the robot with the captured blood clot from the vessel, "said Anna Pozhitkova, engineer at the International Scientific Center SCAMT ITMO.

Soft robots have already successfully shown themselves in in vitro studies (in a test tube): scientists placed them in a glass tube with a diameter like a vein and a flow of liquid, the viscosity of which is similar to the viscosity of blood, and fibrin (medical) thrombs were used as clots. The reprogramming process, the transformation of robots into a liquid-moving spiral, was started and controlled using a magnetic installation capable of generating magnetic fields in different directions.

The structure of the material and the ability to control robots with rotating magnetic fields make our method safer. Thanks to the softness of the material, the walls of the vessels will not be injured when the robots move, and remote control using a magnetic installation will allow you to make fewer interventions in the body. Also, our robots can even make their way to hard-to-reach places: in winding and limited environments, "Anna Pozhitkova added.

According to scientists, the results obtained are an initial stage in the creation of a minimally invasive method of treating thrombosis. The study revealed a number of non-obvious questions that will help avoid many problems at the in vivo stage (testing in living organisms): for example, what are the features of the movement of soft materials in liquids, what design to use for different types of blood clots and how to provide remote control of robots.

The project was supported by a grant from the Russian Science Foundation (No. -21-73-10150).