Researchers from the Indian Institute of Technology, Guwahati have successfully engineered a cost-effective, gel-based wearable device that is capable of recording motion signals. The Organohydrogel sensor, placed on the bodies of patients in comatose states or facing similar conditions, through a wireless device and a smartphone can monitor subtle movements over an extended period. This provides healthcare professionals with invaluable insights into patient conditions and appropriate interventions can be taken.

Flexible and wearable electronics play a pivotal role in augmenting human capabilities, serving functions like artificial skin and prosthetics to assist human movements or integrating with clothing and the human body in areas like bioelectronics, wearable sensors, energy-storage devices, and stretchable optoelectronic devices. Particularly, stretchable wearable devices are extremely beneficial for sensing minor movements of body parts. In situations where monitoring minute limb movements is crucial, such as comatose patients or similar conditions, stretchable gels are employed. However, the current gel technologies exhibit limitations in mechanical properties, lacking ultra-stretchability and self-healing abilities. Additionally, they often lose sensitivity in extreme temperature conditions.

Addressing this gap, a research group at IIT Guwahati led by Prof Debapratim Das, Department of Chemistry has fabricated an organohydrogel. This innovative material exhibits remarkable characteristics, including exceptional stretchability (1000% at strain, sustained for over 100 cycles), self-healing capabilities, anti-freezing, conductivity, as well as outstanding mechanical strength and adhesive properties even after it is kept at −20 °C for a long time.

Speaking about the breakthrough research Prof. Debapratim Das, Department of Chemistry, IIT Guwahati, said, ”We introduced a secondary cross-linking to significantly boost the mechanical properties of the gel and employed precise ratios of glycerol and water to ensure environmental tolerance from -20 to 40 °C. Furthermore, our findings reveal the gel’s remarkable biocompatibility, allowing its safe application on human skin without any side effects.”

The findings of the study have been published in the prestigious ACS Applied Material and Interfaces. The co-authors include Ms. Ritvika Kushwaha, Mr. Souradeep Dey, Ms.  Kanika Gupta, Prof. Biman B. Mandal, and Prof. Debapratim Das.

Speaking about its application Prof. Biman B Mandal, Department of Biosciences and Bioengineering, IIT Guwahati, said, ”During our practical wearable sensing tests, the sensor showed high sensitivity to detect major human joint motions such as elbow, finger, and wrist bending as well as micro motions such as muscle movement around the throat during swallowing and expressions such as smiling and frowning. Because of its wide environment tolerance, it can also be used under extreme conditions like sub-zero temperature during mountaineering etc.”

Furthermore, the researchers fabricated a device that was connected through a smartphone via Bluetooth where signals were recorded upon deformation of the smart gel, which shows that the gel holds great promise as a wearable device.

This pioneering research has been funded by the Core Research Grant (CRG) from the Science and Engineering Research Board (SERB), Board of Research in Nuclear Sciences (BRNS). This marks a significant stride toward enhancing the capabilities of wearable electronics, promising a future where flexible sensors play a vital role in healthcare and beyond.