“The biggest challenge really was to make it smart,” said Huanyu “Larry” Cheng, James L. Henderson, Jr. Memorial Associate Professor of Engineering Science and Mechanics at Penn State, discussing how scientists working on the next generation of soft robots encountered challenges. These robots, flexible enough to emulate the motion of living organisms, though, have made a huge promise in terms of exploring disaster sites, or delivering medicine within the human being. But their potential has long been limited by the difficulty of incorporating flexible electronics into their soft structures a problem Cheng and his team have taken on directly.
Soft robots are a shift from more traditional life-size robots, allowing for a level of stretchability that no rigid robot can offer in tight spaces. They have applications in search-and-rescue missions, as well as navigating complex paths inside the human body. In disaster scenarios, these robots might crawl out of the rubble of an earthquake to detect trapped victims, while in medical settings, they might deliver drugs to the precise location in the body where they are needed. Cheng’s team, whose work was published recently in the journal Nano-Micro Letters, has developed a system that combines flexible electronics with magnetically controlled motion and allows these robots to operate autonomously and interact with their environments.
The robots move by being composed of flexible structures embedded with hard magnetic materials that respond in predictable ways to external magnetic fields. This does away with the need for onboard power sources or physical connections, such as wires. By varying the strength and direction of the magnetic field, they can control the movement of the robots with precision making them bend, twist or crawl. “We wanted to design a system where soft robotics and flexible electronics work together seamlessly.” said Cheng. By maintaining their flexibility with strong performance and heavy integration, these robots have lived up to their early promise.
But that journey was not a straightforward one. These flexible electronics, while adaptable, remain relatively stiff compared with the soft robotic material and would likely impede joint movement. Cheng’s team got around this by spreading out the electronic components throughout the robot’s structure, minimizing their effect on flexibility. Another challenge was reducing magnetic interference, which can disrupt electronic signals and sensor operations. “Magnetic fields are crucial for controlling motion, but they can also disrupt electronic signals,” Cheng said. The team ensured that the sensors remained functional, despite the presence of strong magnetic fields, through careful design.
The consequences of these advances are profound. In search-and-rescue missions, these robots could independently make their way over rubble by sensing extreme heat or navigating obstacle. In health care, they might respond to environmental stimuli such as pH shifts or pressure to deliver drugs to the site of need, or to sample bodily fluids precisely. The robots are designed to work with minimal human intervention, creating new options for non-invasive treatments and diagnostics. Cheng’s team, for its part, is being inspired by the idea of a “robot pill” that can be swallowed to traverse the intestinal tract and help detect diseases, and even deliver drugs directly to where they are needed.
This envisage dovetails with active investigation into robotic capsules that include the SOMA pill created by researchers at MIT. With their series of bulbous and skinny appendages that look to date back in the evolutionary tree to the leopard tortoise, these capsules are weighted so they will self-orient on the stomach and deliver medicines precisely. Once placed, a carbohydrate pellet dissolves and a spring mechanism injects drug into the stomach tissue. These technologies hold the potential to transform the delivery of biologics, which are frequently degraded by digestive acids and enzymes when delivered orally.
The same can be said for grain-sized robots created at Nanyang Technological University, Singapore. These robots can carry multiple drugs and release them in programmable orders, showcasing the promise of precision medicine. “Traditional methods of drug delivery like oral administration and injections will seem comparatively inefficient,” said the study’s lead researcher, Assistant Professor Lum Guo Zhan of NTU. These robots could greatly enhance therapeutic outcomes with reduced side effect through navigating complex body environments.
The future of soft robotics stretches beyond medicine. In disaster response, these robots could be used in situations when traditional tools fail. Their ability to survive unstructured environments while functioning autonomously makes them ideally suited to navigating debris and finding survivors. “These findings show that our soft robot could potentially play a key role in the future of targeted drug delivery, especially in those treatments such as cancer therapies that need precise control over multiple drugs,” said Yang Zilin, Research Fellow at NTU.
[037] The future of soft robotics lies in its versatility and accuracy. Whether it is making its way up steep inclines in the central nervous system or gliding through the fluid flows of the gastrointestinal tract, these robots are radically advancing the boundaries of engineering and medicine. While Cheng and his team are working to refine their technology, the potential uses from treating cardiovascular diseases to making minimally invasive diagnostics possible are limitless. The NEXPL, working with the original development team, explores seamless integrations between flexible electronics and soft robotics as a crucial avenue for not only treating these challenges but also re-imagining how we interact with the world.
