Singapore Scientists Create 3D-Printed Active Fabric for Medical Use

It seems almost fantastical, yet it’s real.

A flexible, wearable fabric that can stiffen on demand has been developed by Nanyang Technological University (NTU) scientists in Singapore. Crafted through a combination of geometric design, 3D printing, and robotic control, RoboFabric can quickly be made into medical devices or soft robotics such as rehabilitative products, joint supports, or limbs for drones.
 
The NTU research team has developed an elbow support from the versatile material, helping people carry heavier loads. A wrist support prototype has also been made, which could help stabilize joints for daily activities and benefit patients with Parkinson’s Disease who experience trembling. As a joint support, RoboFabric can reduce human muscle activity by up to 40%, according to the research team’s findings, which have been published in the scientific journal Advanced Materials. 
 
Inspired by pangolins and armadillo scales (they interlock to form a protective shell), the patent-pending technology leverags an advanced mathematical algorithm that designs an interlocking tile system. The 3D-printed tiles are then joined together by metal fibers running through tiny channels between them, or by an external soft case, which requires the constant application of negative air pressure or a vacuum. When the fibers are contracted, the tiles interlock and stiffen, increasing the rigidity of RoboFabric over 350 times and providing additional strength and stability.
 
“We were inspired by how animals often have multiple functionalities for their limbs through the use of intricate structures, much like the shape-morphing and stiffness-variation in octopuses,” lead scientist and Nanyang Assistant Professor Wang Yifan, NTU School of Mechanical and Aerospace Engineering, and NTU Robotics Research Center, said. “We envision that in future, patients who need a plaster cast for fractures would have the option of customizing a flexible limb support that is fabric-like before stiffening. Unlike conventional rigid and unremovable casts, they would also be easy to put on or remove at the touch of a button. In daily use, joint supports can also help the elderly in their daily tasks, helping to reduce the muscle strength needed for heavier loads.” 
 
To customize the joint support, a 3D scan of a wrist or the elbow is uploaded to proprietary software, through which a special algorithm can automatically dissect a 3D model into dozens of geometric tiles that can be printed in 60 minutes. The metal fibres must then be threaded through the holes between the tiles and connected to an electric device that can quickly tighten or loosen the cables. This threading process is currently done by hand, but the team is hopeful it could be automated in future, similar to the way in which a machine restrings badminton racquets.
 
“This technology could be potentially useful in several cases, such as individuals with joint injuries, as it could allow safe adjustment of movement range during recovery. For those with upper limb motor weakness, such as post-stroke patients, RoboFabric could provide support to perform some functional tasks,” stated Adjunct Associate Professor Loh Yong Joo, head and senior consultant at the Department of Rehabilitation Medicine, Tan Tock Seng Hospital. Joo also is the director of Clinical Innovations at the hospital. “Additionally, individuals with movement disorders like Parkinson’s disease may benefit from the stability RoboFabric offers, which stabilizes the movement trajectory to complete functional tasks safely. If adapted for knee applications in future, it may even serve as a stabilising orthosis to improve gait patterns and help prevent falls.”
 
RoboFabric could also be applied in robotics. In their latest research paper, published in Science Robotics, Wang’s team demonstrates a tiny robot made of thin waveshaped tiles sealed in an elastic envelope.
 
When a vacuum is applied, the RoboFabric transitions to its designated shape and becomes stiff. Conversely, when the vacuum pressure is removed, it relaxes into a soft state. This actuation of stiffening and softening allows the small robot to climb like a worm or swim in water, carrying small loads or protecting fragile assets by forming a rigid shell around them. These capabilities are important for exploration and rescue robots that need to move in complex terrains and provide protection on demand.
 
In another demonstration, four such robots are combined to form a robotic gripper on a drone. When made rigid, the soft gripper curls up and can pick up small items, similar to a claw machine. To drop the items, it relaxes. The gripper doubles up as a shock-absorbing pad for hard landings when it curls up; while soft, the grippers can be folded into the drone body and do not affect its flight function.
 
The team is exploring collaborations with industry partners who have expressed interest in the technology and are hoping to partner with them for deployment trials in healthcare and robotics. The research project is supported by the Manufacturing, Trade and Connectivity (MTC) Individual Research Grant and the Young Individual Research Grant, managed by Singapore’s Agency for Science, Technology and Research.
 
A research-intensive public university, Nanyang Technological University, Singapore (NTU Singapore) has 35,000 undergraduate and postgraduate students in the Business, Computing & Data Science, Engineering, Humanities, Arts, & Social Sciences, Medicine, Science, and Graduate colleges. NTU is also home to autonomous institutes—the National Institute of Education, S. Rajaratnam School of International Studies, and Singapore Centre for Environmental Life Sciences Engineering—as well as various research centers such as the Earth Observatory of Singapore, Nanyang Environment & Water Research Institute, and Energy Research Institute @ NTU (ERI@N).