During lab testing, people know they are being watched, but outside the lab, behavior may be different.

“One of our ideas is that we could utilize these novel textiles outside of a laboratory setting — walking down the street, at home, wherever,” said Thostenson.

Sagar Doshi, a doctoral student in mechanical engineering at UD, is the lead author on the paper. He worked on making the sensors, optimizing their sensitivity, testing their mechanical properties and integrating them into sandals and shoes. He has worn the sensors in preliminary tests, and so far, the sensors collect data that compares with that collected by a force plate, a laboratory device that typically costs thousands of dollars.

“Because the low-cost sensor is thin and flexible the possibility exists to create custom footwear and other garments with integrated electronics to store data during their day-to-day lives,” Doshi said. “This data could be analyzed later by researchers or therapists to assess performance and ultimately bring down the cost of healthcare.”

This technology could also be promising for sports medicine applications, post-surgical recovery, and for assessing movement disorders in pediatric populations.

“It can be challenging to collect movement data in children over a period of time and in a realistic context,” said Robert Akins, Director of the Center for Pediatric Clinical Research and Development at the Nemours – Alfred I. duPont Hospital for Children in Wilmington and affiliated professor of materials science and engineering, biomedical engineering and biological sciences at UD. “Thin, flexible, highly sensitive sensors like these could help physical therapists and doctors assess a child’s mobility remotely, meaning that clinicians could collect more data, and possibly better data, in a cost-effective way that requires fewer visits to the clinic than current methods do.”

Interdisciplinary collaboration is essential for the development of future applications, and at UD, engineers have a unique opportunity to work with faculty and students from the College of Health Sciences on UD’s Science, Technology and Advanced Research (STAR) Campus.

“As engineers, we develop new materials and sensors but we don’t always understand the key problems that doctors, physical therapists and patients are facing,” said Doshi. “We collaborate with them to work on the problems they are facing and either direct them to an existing solution or create an innovative solution to solve that problem.”

Thostenson’s research group also uses nanotube-based sensors for other applications, such as structural health monitoring.

“We’ve been working with carbon nanotubes and nanotube-based composite sensors for a long time,” said Thostenson, who is affiliated faculty at UD’s Center for Composite Materials (UD-CCM). Working with researchers in civil engineering his group has pioneered the development of flexible nanotube sensors to help detect cracks in bridges and other types of large-scale structures. “One of the things that has always intrigued me about composites is that we design them at varying lengths of scale, all the way from the macroscopic part geometries, an airplane or an airplane wing or part of a car, to the fabric structure or fiber level. Then, the nanoscale reinforcements like carbon nanotubes and graphene give us another level to tailor the material structural and functional properties. Although our research may be fundamental, there is always an eye towards applications. UD-CCM has a long history of translating fundamental research discoveries in the laboratory to commercial products through UD-CCM’s industrial consortium.”