Researchers in Singapore have developed one of the smallest and most versatile sensors yet for healthcare applications with the design of a stretchable microfiber sensor with the diameter of a strand of human hair.
A team from the National University of Singapore (NUS) developed the sensor, which can be woven into textiles—such as a glove—to monitor the vital signs of patients, such as heart rates and blood pressure.
The sensor solves a key challenge to the development of wearable technology—the lack of comfort in the design of the sensors necessary to provide the data-collection technology such devices use, said Professor Lim Chwee Teck of the Department of Biomedical Engineering in the National University of Singapore (NUS) Faculty of Engineering.
“Wearable and flexible technology has gained significant interest in recent years, leading to tremendous progress in soft and wearable sensors,” he told Design News. “However, current devices have various limitations, such as not being able to fit well on the skin, or are uncomfortable to wear.”
Professor Lim Chwee Teck (standing) of the Department of Biomedical Engineering in the National University of Singapore (NUS) Faculty of Engineering works with team members to test a microfiber sensor woven into a glove that they developed. The tiny sensor has the diameter of a human hair and can be used to monitor the vital signs of patients, such as heart rates and blood pressure. (Source: Lim Chwee Teck, NUS)
The sensor developed by Lim and the team, on the other hand, conforms well to curvatures of the skin as it bends, and provides no discomfort for the person wearing it, who barely knows it’s there, he said.
“The sensor is as tiny as a thread, which is imperceptible and hardly visible when woven into gloves and bandages,” he said
Moreover, despite its tiny size, the sensor is highly sensitive and also has excellent electrical conductivity and mechanical deformability, Lim said.
“It functions like a conductive thread, and is designed to be highly durable and to withstand washing,” he said. “It can provide real-time monitoring with high precision. The sensor is cost effective to produce and easy to maintain, and the process for electronics integration is simple.”
The structure of the sensor itself team is comprised of a liquid metallic alloy—gallium indium—which serves as the sensing element and is encapsulated within a soft silicone microtube, Lim said. “The two inlets are sealed with copper wires and connected to a multi-meter to measure electrical resistance,” he explained.
The sensor can be used to monitor a person’s pulse waveform in real time, information that can be used to determine one’s heart rate, blood pressure, and stiffness in blood vessels, as well as bandage-pressure sensing, Lim said.
“The detection of pulse waveform is achieved by weaving the sensor into a glove, which can then be worn to monitor these key vital signs,” he said. “Similarly, the sensor is also woven into bandages for pressure monitoring.”
Due to its versatility, the sensor also could be used for a wide range of other applications as well, such as healthcare monitoring, smart medical prosthetic devices, and artificial skin, Lim added.
Researchers have already published papers about their work in the journals Proceedings of the National Academy of Sciences (PNAS) and Advanced Materials Technologies.
The team has filed a patent for the sensor, and they currently are working with Singapore General Hospital to test its application for bandage-pressure monitoring, Lim said.
The team also is exploring new applications for the technology, including smart socks for feet-pressure monitoring to help patients with diabetic foot ulcers, as well as smart mouth guards to assist patients who have problems with grinding their teeth, he added.
“We are also refining the sensor design and reducing the size of its accessories to improve the user-friendliness of the device, and are keen to work with commercial partners to bring the novel sensor to market,” Lim said.
Elizabeth Montalbano is a freelance writer who has written about technology and culture for more than 15 years.