Three medical robots as soft as humans

The insides of the human body are mostly malleable (yes, this is a technical term), and our soft insides do not always cope with the placement of rigid objects in them. Sharp corners can damage organs and blood vessels, and the body's defense system can surround a foreign object with scar tissue and prevent it from performing the function assigned to it. Researchers are working on making soft robots that the body will accept more readily, which will allow the machines to closely interact with the fabric without harming security.

The three experimental robots presented are designed for different purposes - two of them are implants, and the third is a potential surgeon's tool. But they all show us a more gentle type of robots, which appeared thanks to new materials and flexible actuators.

Heart hugging

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In the chest 41 million people around the world failing hearts gradually lose their effectiveness, performing the vital task of pumping blood. Some patients with heart failure are on the waiting list for a transplant, while others are implanted with metal pumps, heart-assist devices [ventricular assist devices, VAD ]. But the presence of VAD increases the risk of blood clots appearing when the fluid flows through metal or plastic surfaces.

In search of a more advanced pump, an international team of researchers manufactured a silicone sleeve that hugs the heart outside, protecting the blood flow from contact with a robot that rhythmically squeezes the heart. The design of the sleeve was inspired by the structure of the muscles of the heart. Its inner layer is compressed with the help of concentric rings, and the outer - like a spiral. At an early stage of development, the device uses 14 pneumatic actuators (6 in the concentric layer, 8 in the spiral), which are triggered separately from the air pumping - this allows experimenters to test various compression modes. In an experiment with live pigs, researchers have shown that the device can recognize and match the natural rhythm of the heart, setting a steady rhythm that corrects unreliable cuts.

Soft robots are potentially not only capable of supporting a failing body, as co-author of the work, Helen Rocher , postdoc at the National University of Ireland says. In September she will be transferred to MIT and will begin work as a senior teacher in mechanical engineering. “By copying the natural properties of an organ, you’ll be better able to help it - and maybe you can try to rehabilitate it or help it regain function,” she says. - If you just take over all of its functions, it will not be better.

Dosing Medication

When thinking about Swiss chronometers, such adjectives as “soft” and “pliant” are unlikely to come to the first place, so researchers from Columbia University get a top five for their creative approach. Reproducing the Maltese clockwork in a soft hydrogel, they created a biocompatible robot , capable of counting time and releasing doses of medication inside the body.



Samuel Sia , a professor of biomedical engineering at Columbia University, created a biobot based on a watch with one simple hydrogel gear that incorporates iron nanoparticles. This allows researchers to rotate it with an external magnet. Each next click opens a hollow chamber capable of releasing a dose of fluid. Sia suggests that in the treatment of cancer, such implants can provide local delivery of chemotherapy drugs to rid the rest of the body of the toxic effects of the drug. After checking the device in mice with bone cancer, he found that the drugs delivered by the biobate killed more tumor cells and spared more cells of the rest of the body than typical systems for chemotherapy. Moreover, due to the presence of an external control panel, doses can be determined at the request of the physician.

The hardest thing was to achieve a perfectly suitable material, says Sia, not too soft, not too hard. “I don’t want to lose the pleasant properties of a hydrogel, but if the material shrinks like a jellyfish, you won’t make robots out of it,” he says. “It must be strong enough to work like a tiny implantable machine.”

Gently grasping

Modern surgeons use a variety of different tools to work with your internal organs. For example, one tool can be used to push the fat layer, the other - to cut a tumor on the kidney. Surgeons scrupulously try to avoid unnecessary damage to the tender flesh, and it may be easier for them to achieve this with soft instruments from Xuanhe Zhao.



Zhao, an associate professor at MIT, specializes in mechanisms of various kinds, and has developed several robotic hydrogel devices , each of which is interwoven hollow cubes. To activate the device, the syringe pours water into the robot differently, so that the robot straightens or twists, resulting in fast and strong movements. One such robot, resembling a five-fingered hand, demonstrated his art, catching a swimming goldfish, and then releasing it without harm. Zhao's team works together with medical researchers to create hydrogel hands that can hold organs during robotic surgeries.

Another application of this technology can be a robot, twisting around the intestine and rhythmically compressing it, imitating the wavelike movements of peristalsis, promoting food through the digestive tract. It seems that tomorrow's soft robots can grab anything inside the body.