The researchers noted that the soft robots can perform various well-controlled movements — such as bending, expanding and twisting — inside biological environments.

Source: University of North Carolina at Chapel Hill

The team also suggests that such bio-inspired soft robots employed as implants promise major advancements in the realm of surgery, diagnostics, drug delivery, prosthetics, artificial organs and rehabilitation tools, among other applications.

Making them appropriate for such applications is that the soft robotic implants can change shape and function, much like biological tissues. Further, they can match the softness of tissues, offer therapeutic treatments and perform real-time monitoring. Additionally, the soft robotic implants reportedly enhance diagnostic and therapeutic precision by incorporating sensing and actuation, possibly functioning as artificial organs.

To create the soft robots, the team combined two layers — an electronic skin (e-skin) composed of functional nanocomposites and an artificial muscle derived from a Poly(N-isopropyl acrylamide) or PNIPAM hydrogel. The team noted that while the e-skin detects touch, pressure, temperature and chemicals, the hydrogel muscle can both retract and relax.

In addition to being able to bend, expand and twist, the soft robot implants can also wirelessly move, sense and communicate, thereby enabling minimally invasive operations within the body.

The team suggests that the gentle attachment to tissues makes the soft robot implants less likely to cause stress and harm, and some of their designs include a bladder-wrapping robot for bladder control, a blood vessel cuff for flow measurement, an ingestible robot for stomach monitoring and a heart-grasping robot for epicardial sensing and stimulation.

Such devices can offer continuous monitoring of internal conditions like blood pressure and bladder volume. Likewise, they can be ingested to monitor and treat conditions in the stomach and offer treatments including electrical stimulation and they can also shape-shift to fit organs for better sensing and treatment.

Specifically, the researcher’s thera-gripper, which is an ingestible robot, can monitor stomach pH levels and deliver drugs periodically, thus enhancing gastrointestinal treatment. The gripper can also attach to the heart where it would monitor electrophysiological activity, measure contractions and offer electrical stimulation to regulate heart rhythm.

Meanwhile, a robotic bladder gripper can measure volume and offer electrical stimulation for overactive bladders, while a robotic cuff wraps around blood vessels to accurately measure blood pressure in real-time.

The researchers described their findings in the article, “Skin-inspired, sensory robots for electronic implants,” in the journal Nature Communications.