A soft robot which embraces failing hearts to keep blood pumping could one day be used to help keep people with heart failure alive.
Developed by researchers from Harvard University and described last week in the academic journal Science Translational Medicine, the robotic sleeve was created to mimic the composition of human heart tissue.
When wrapped around a heart, the robot uses compressed air to power artificial muscles made of silicon, compressing and twisting to assist ailing hearts in pumping blood without ever coming into contact with the fluid.
According to the paper, the researchers have been able to tailor the soft robot to twist and compress hearts in sync with a heart's existing rhythm on either one or both sides of the organ, depending on the patient's needs.
"Our approach used a biologically inspired design to orient individual contracting elements or actuators in a layered helical and circumferential fashion, mimicking the orientation of the outer two muscle layers of the mammalian heart," the paper's abstract reads. "The resulting implantable soft robot mimicked the form and function of the native heart, with a stiffness value of the same order of magnitude as that of the heart tissue."
Heart failure affects 41 million people worldwide, including five million in the US alone. When heart conditions reach critical end stages, heart transplants are the best option -- but a shortage of suitable organs available results in many patients being forced to rely on ventricular assist devices (VADs), mechanical devices which are used to push the heart into lasting a little longer.
VADs do not replace true heart functions and often require patients to take medication for the rest of their lives, leaving sufferers open to other conditions including infection and blood clots.
However, as Harvard's sleeves do not come into contact with a patient's blood, this removes the need for blood thinners or anticoagulants, and may also reduce problems associated with today's more invasive cardiac devices.
So far, the robot has been tested in adult pigs which have suffered drug-induced cardiac arrests, and the robots were able to ensure blood continued pumping despite failing hearts.
The soft robot is not perfect and implanting the device came with a number of problems which need to be resolved. During the pig trials, for example, the researchers say some inflammation occurred due to the robot's turning and twisting, but the team was able to reduce friction by using a hydrogel to form a protective layer between the sleeve and organ.
While there is a long way to go before the soft robots are accepted for human trials or use, there is hope that such robots could one day replace ventricular assist devices and become a less invasive alternative to current solutions -- or will give those waiting for heart transplants more time.
[Correction 17.21 GMT: The original article stated that MIT researchers were involved in the project, rather than Harvard University.]