Some electronic sensors can be worn on the skin like a “tattoo” to monitor body parameters such as pulse, respiration rate and glucose levels. They are soft, flexible and lightweight, making it easy to monitor these parameters non-invasively without requiring bulky machinery. These sensors are usually made from thin, flexible and electrically conductive 2D materials such as graphene. Ti3C2-MXene is a new addition to the family of 2D nanomaterials that has displayed excellent properties to design flexible sensors.
A collaborative research group at IISc has synthesised free standing films of Ti3C2-MXene and devised a new method to fabricate flexible tattoo sensors to measure mechanical strain. This method involves using a pulsed laser to precisely cut and create a specific pattern on the MXene film for the given application. The pattern determines parameters such as electrical resistance and sensitivity, which regulate the working of the sensor. The fabricated film is then packaged between sheets of a biocompatible polymer called PDMS, which gives it enough mechanical stability to be used as a disposable tattoo sensor. This ultrathin tattoo can monitor respiration and pulse rate while remaining largely unnoticed.
Tattoo sensors are more comfortable for users compared to existing wearable gadgets and can be easily transferred on the skin. This method of designing wearable sensors provides a more accurate alternative to other techniques such as inkjet printing and stamping. It is also rapid, less expensive and can easily be scaled up. Such sensors have the potential to become useful for medical diagnostics and related applications.
Kedambaimoole, Vaishakh, Neelotpala Kumar, Vijay Shirhatti, Suresh Nuthalapati, ProsenjitSen, Mangalore ManjunathaNayak, Konandur Rajanna, and Saurabh Kumar. Laser-Induced Direct Patterning of Free standing Ti3C2-MXene Films for Skin Conformal Tattoo Sensors. ACS Sensors (2020).