Customisable soft robot fits around a heart and helps it beat

Engineers develop a robot sleeve that twists and compresses in synchronisation with a beating heart.
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Soft robot helps hearts beat. Image: Ellen Roche/Harvard University

Engineers and researchers at Harvard University and Boston Children's Hospital have developed a customisable soft robot that takes the form of a sleeve which fits around a heart and helps it beat.

The soft robot sleeve twists and compresses in synchronisation with a beating heart, helping augment cardiovascular functions that have been weakened by heart failure.

Heart failure affects 41 million people worldwide. Today, some of the options to treat it are mechanical pumps called ventricular assist devices (VADs), which pump blood from the ventricles into the aorta, and heart transplant. By virtue of their function, VADs require direct contact with blood. This makes matters more complex as there is the risk of blood clotting, and patients have to take potentially dangerous blood thinner medications.

The soft robot does not require contact with blood and simply wraps outside the heart. As most people with heart failure still have some function left in their heart, the robotic sleeve may help their heart work well enough that their quality of life can be restored, and used as a solution to bridge a patient to transplant, or to help in cardiac rehabilitation and recovery.

The research was a collaboration between the Harvard John A. Paulson School of Engineering and Applied Sciences, The Wyss Institute of Biologically Inspired Engineering at Harvard University and Boston Children’s Hospital.

According to Conor Walsh, senior author of the paper, the work represents an exciting proof of concept result for the soft robot, demonstrating that it can safely interact with soft tissue and lead to improvements in cardiac function.

"We envision many other future applications where such devices can delivery mechanotherapy both inside and outside of the body,” he said.

The thin silicone sleeve uses soft pneumatic actuators placed around the heart to mimic the outer muscle layers of the mammalian heart. The actuators twist and compress the sleeve in a similar motion to the beating heart. The device is tethered to an external pump, which uses air to power the soft actuators.

The sleeve is customisable. So if a patient has more weakness on the left side of the heart, for example, the actuators can be tuned to give more assistance on that side. The pressure of the actuators can also be adjusted over time, as the patient's condition changes.

The sleeve is attached to the heart using a combination of a suction device, sutures and a gel interface to help with friction between the device and the heart.

More research needs to be done before the sleeve can be implanted in humans but the research is an important first step towards an implantable soft robot that can augment organ function.

Engineers Australia is organising the Asia Pacific Conference on Medical and Biological Engineering which is being held in conjunction with the Australian Biomedical Engineering Conference in Sydney on 17-19 July 2017. 
The conference will feature an exciting line-up of local and international speakers. 
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[Image credit: Ellen Roche/Harvard University]