| New and exciting detection methods are being developed to monitor most aspects of human performance as well as environmental exposure. Research has focused on field personnel and occupational workers since there are many factors that influence their performance and that can result in catastrophic consequences. For example, dehydration can affect human performance leading to slow cognitive response as well as decreased energy performance. Further, occupational conditions of some workers, such as firefighters, can be quite dangerous and hazardous gas exposure can be a frequent occurrence. Developing new technology that can monitor these personnel is crucial in helping to prevent accidents and maintain a safe workplace. In this work, we describe an optical carbon dioxide (CO2) sensor based on luminescent quenching of hydroxy-pyrenetrisulfonic acid (HPTS). A low-cost CMOS image array was used as detector, while cross-polarization was used to filter the excitation light and reduce background interference. The sensor exhibited excellent performance, with high sensitivity over a wide dynamic range of 0--100% CO2. As a proof-of-concept, the sensor was field-tested with automobile exhaust and benchmarked with a commercial sensor. By using an image sensor often found in consumer products, a compact, low-cost luminescence-based CO2 sensor was successfully demonstrated with performance comparable to that of the commercial sensors. In this work, we also describe a sweat monitoring patch capable of continuously monitoring electrolyte concentrations in sweat. The patch is based on a miniaturized ion selective electrode (ISE) capable of monitoring changes in sodium and chloride concentrations. The sensor showed good reliability, sensitivity and linearity in varying concentrations of diluted samples. By integrating sensor on a patch, a wearable, point-of-care sensor platform was demonstrated. |
