Move over, ants: This tiny amphibious soft robot is the new master of cargo

Could the future of rescue missions and exploration lie in the hands—or rather, the flexible movements—of a swarm of lightweight, soft, and intelligent robots? Imagine swarms of soft-bodied robots, working with the coordinated efficiency of an ant colony, navigate complex and unpredictable environments—seamlessly transitioning between murky waters, muddy banks, and rugged obstacles—to deliver essential payloads. This vision is steadily moving from science fiction to tangible reality through the field of soft robotics. Unlike their rigid, industrial counterparts, soft robots are constructed from compliant materials that provide remarkable deformability and adaptability. This enables them to traverse confined spaces and interact safely with delicate environments and biological tissues, offering transformative potential for applications in search and rescue, ecosystem monitoring, and targeted medical procedures.

However, a significant technological bottleneck has impeded the widespread and practical deployment of these machines. The current generation of soft robots often excels primarily in highly specialized niches. Most are designed to respond to a single external stimulus—such as light, heat, or a magnetic field—and are typically optimized for operation in a single environment, like either land or water. This lack of versatility presents a major limitation in real-world scenarios, which are inherently complex and amphibious. A more profound challenge arises when attempts are made to integrate multiple responsive mechanisms: simply combining, for instance, a heat-sensitive material with a magnetic driver often leads to conflicting signals and internal interference, causing unreliable actuation and loss of precise control. The primary challenge, therefore, has been to develop a unified system that can harmoniously integrate multiple environmental "senses", enabling a single soft robot to adapt and perform coherently across the dynamic boundary between water and land.

The blueprint for solving this complex problem was found in the natural world. Insects such as ants and whirligig beetles are masters of different-terrain navigation Insects like ants and rotating beetles are masters of navigating diverse terrains, reacting swiftly to avoid danger when they sense it. Their actions are governed by a continuous, synergistic interpretation of their surroundings. This principle of synergistic response inspired research conducted by Professors Chen Xin and Chen Yun at Guangdong University of Technology, in collaboration with Dr. Guo Yuanhui from Guangdong Polytechnic Normal University. Their goal was to engineer a soft robot that could perceive and respond to multiple environmental cues simultaneously, much like its biological counterparts.

The team's groundbreaking solution focused on creating a novel, multi-layered composite film that functions as an advanced "artificial muscle." The fabrication process is both innovative and sophisticated. They began with a common polyimide (PI) film and applied a controlled chemical modification using a strong alkali. This treatment breaks specific molecular bonds on the film's surface, successfully converting it into a layer of polyamic acid (PAA). The PAA layer is highly responsive to changes in temperature and humidity, expanding or contracting to provide the first two stimulus responses. The next step involved embedding neodymium iron boron (NdFeB) magnetic particles were embedded into a separate silicone rubber layer, which was then bonded to the PI-PAA film. This final layer adds a third, powerful response to external magnetic fields, enabling precise remote steering and propulsion. The brilliance of this "triple-layer sandwich" design lies in its clear segregation of each responsive layer’s function, effectively preventing the interference that has hindered previous multi-stimuli robots.

The capabilities enabled by this design are remarkable. The resulting robot, weighing a mere 8 milligrams, exhibits a level of agility and strength that belie its minuscule size. It achieves impressive speeds of up to 9.6 cm/s (approximately 32 body lengths per second) on the water's surface—performance comparable to that of actual whirligig beetles. Guided by a rotating magnetic field, it performs a robust rolling gait, enabling it to climb slopes, transition from underwater to dry land, and navigate complex obstacle courses. Perhaps the most compelling demonstration of its utility is its cargo transport capability. The robot can carry a payload weighing 2.5 times its own body weight over a multi-stage journey. In a vivid experiment, the robot transported a small pebble across a challenging path involving underwater travel, a climb onto land, and a final return to water. Upon reaching its destination, brief exposure to near-infrared light—which locally heats the robot—triggered a programmed shape change, causing it to unfold and release its cargo precisely. After the light was removed, the robot returned to its original shape and retreated under magnetic guidance, completing a full mission cycle of pick-up, cross-terrain transport, and targeted delivery.

This research represents an important advancement from specialized prototypes to general-purpose soft robots. The successful demonstration of a triple-response, amphibious soft robot capable of performing complex tasks opens new opportunities for deploying soft robots in environments that are currently too dangerous or inaccessible for humans or conventional robots. Potential applications include inspecting underwater infrastructure, monitoring polluted wetlands, and operating in disaster zones. By drawing inspiration from nature's synergistic designs, this work contributes to the ongoing development of robots that can operate effectively within the complexities of natural environments.

About Guangdong University of Technology

Guangdong University of Technology is a technology-focused university located in Guangdong province, renowned for its strong engineering and materials science programs. Several of its disciplines ranking within the top 1‰ globally according to ESI. The university emphasizes technological innovation and maintains a close integration with the industrial demands of the Guangdong-Hong Kong-Macao Greater Bay Area.

Website: https://www.gdut.edu.cn/

About Guo Yuanhui from Guangdong Polytechnic Normal University

Lecturer at Guangdong University of Technology. She earned her PhD in Engineering from Guangdong University of Technology in June 2025. Her primary research areas include micro-nano robots and laser processing. She has published five related papers in journals such as Nature Communications and ACS Applied Materials & Interfaces, with one paper recognized as a hot paper and highly cited paper, and two papers featured on the cover.

About Chen Yun from Guangdong University of Technology

Professor at Guangdong University of Technology, his primary research areas include semiconductor wet etching technology and devices, advanced electronic packaging technology and equipment, and laser processing technology and equipment. He has led nearly 20 research projects, including the National Key Research and Development Program and the Excellent Young Scientist Fund from the National Natural Science Foundation of China. He has published over 80 SCI-indexed papers and holds more than 150 authorized patents. He serves as a youth editorial board member for the international journal of Extreme Manufacturing, a youth editorial board member for SmartBot, and as Vice Chairman of the Semiconductor Equipment Division of the Chinese Mechanical Engineering Society. He has received several awards, including the Second Prize for National Scientific and Technological Progress, the First Prize for Technological Invention in Guangdong Province, the First Prize for Science and Technology from the China Machinery Industry, and the Guangdong Patent Gold Award. He has been selected for the National Excellent Young Scientists Program, the Guangdong Provincial Science and Technology Innovation Young Top Talent Program, and the Hong Kong Scholar Program.

Funding information

This work was supported by the National Natural Science Foundation of China [grant number 52422511, Y.C.], Guangdong Basic and Applied Basic Research Foundation [grant number 2022B1515120011, Y.C.], Guangzhou Basic and Applied Basic Research Foundation [grant number 2024A04J6362, Y.C., grant number GZGX-24-01, Y.C.], and Zhuhai Industry-University-Research Cooperation Project [grant number 2320004002350, Y.C].