Researchers at Harvard have developed a soft robotic arm that can lie flat when housed inside an endoscope as it travels through narrow passages in the body, but can pop-up when it needs to be used to manipulate tissues.

Endoscopes are flexible probes used by surgeons that can travel through narrow passages in the body and perform surgical tasks like grabbing and cutting. Typically, they contain rigid surgical tools at their tip. This can make it difficult for surgeons to safely maneuver them, and such rigid tools can even accidentally damage soft tissues in the body.

This problem inspired Harvard scientists to develop a soft robotic arm to perform endoscopic tasks. However, using soft robotics posed some challenges. “At the millimeter scale, a soft device becomes so soft that it can’t damage tissue but it also can’t manipulate the tissue in any meaningful way,” said Tommaso Ranzani, a postdoctoral researcher at the Harvard Wyss Institute and an author on the study, which was recently published in Advanced Materials Technologies. “That limits the application of soft microsystems for performing therapy. The question is, how can we develop soft robots that are still able to generate the necessary forces without compromising safety.”

“We found that by integrating soft fluidic microactuators into the rigid pop-up structures, we could create soft pop-up mechanisms that increased the performance of the actuators in terms of the force output and the predictability and controllability of the motion,” said Sheila Russo, a postdoctoral fellow at the Harvard School of Engineering and Applied Sciences. “We were able to design a device that can lie flat when the endoscope is navigating to the surgical area, and when the surgeon reaches the area they want to operate on, they can deploy a soft system that can safely and effectively interact with tissue.”

The arm can effectively interact with and manipulate soft tissues and could be useful for a variety of surgical procedures. It employs a suction cup to achieve this, which is inspired by the suckers on octopus tentacles. The device can be scaled down to 1 millimeter in size, allowing surgeons to use it in very tight endoscopic procedures, such as those in the brain or lungs.