Wearable chemical sensors from nanotechnology
Recent developments in carbon nanotubes (CNTs) and printed electronics mean that electronics can now be incorporated into everyday materials such as paper and cotton. When used in conjunction with conductive membranes, the potential for cheap and disposable sensors is almost limitless. The EU-funded FLEXSENS (FlexSens: Chemical sensors for the 21st century) project used this strategy to create a flexible chemical sensor platform that can be easily adapted to different uses. The team focused on incorporating sensors into everyday objects and creating disposable, paper-based sensors. Researchers began by defining strategies to incorporate electronics into paper, cotton and rubber, and testing different ways to create chemical sensors. They used an ink made with CNTs to create conductive materials, testing these with different conductive polymers to create the sensor. FLEXSENS created paper sensors for sodium, potassium, calcium and magnesium, and used a lithium paper sensor as a proof-of-concept. Using a similar approach with cotton, researchers created an adhesive bandage that incorporates all of these sensors. The development of solid-contact reference electrodes was a major step forward as they can be used in a wide range of different applications. Moreover, the development of a fully integrated paper-based potentiometric cell will enable the direct determination of lithium in blood. In addition, the creation of a novel creatinine sensor has resulted in the creation of a start-up company for home-based diagnostics. Collaborations with other research groups have yielded other potential sensors that can be worn as a 'tattoo' or that incorporate radio signalling for remote sensing. These low-cost sensors herald the beginning of a revolution in medical sensing technology.
Keywords
Chemical sensors, wearable, carbon nanotubes, electronics, cotton, FLEXSENS, lithium
