Abstract:
Sweat carries valuable information about our physiological and cognitive status. Measurement of various biomarkers in sweat provides a pathway for the assessment of fatigue or cognitive ability for an individual, along with additional physical conditions such as dehydration. As such, there has been a significant interest in developing non-invasive, wearable sensors to detect a range of biomarkers from sweat. This paper will describe an approach for development of a wearable sensing platform for non-invasive detection of sweat-based stress and fatigue biomarkers (such as Orexin A, cortisol and IL-6). The wearable platform is composed of miniaturized electrical sensors integrated with flexible, printed microfluidic components that allow for on-demand sample acquisition and transport of sweat, and subsequent detection of biomarkers at the sensing surface site. Sample acquisition is achieved utilizing absorbent pads, hydrophilic microchannels, and printed electro-wetting valves enabling capillary pumping to continuously deliver sample to the sensor. Biomarker detection is accomplished utilizing multivariable resonance (RF) impedance sensors and field effect transistor (FET) sensors functionalized with an appropriate biorecognition element (BRE) chemistry to provide selective binding of the analyte of interest. The presentation will detail the design, fabrication, and performance of the sensors under various conditions, along with aspects for microfluidic subsystem integration.