Self-Powered Flexible Wearable Sensing Platform for Ascorbic Acid Detection in Sweat

Laser-scribed graphene electrodes (LSGEs) are an excellent platform for biosensors due to their electronic properties, large surface area, and high porosity that enhances the electron transfer rate. The flexibility of LSGEs combined with the advantages of electrochemical techniques for a portable device is very suitable for wearable applications. We report a lightweight (< 2 g) wearable platform paired with nonmodified LSGE to detect ascorbic acid (AA) in sweat. Electrochemical techniques, such as square wave voltammetry (SWV) and chronoamperometry (CA), were used to acquire the data. The acquired data are transmitted wirelessly to the user via Bluetooth (BLE) or through universal asynchronous receiver–transmitter (UART) using a custom-made application. The limits of detections (LODs) achieved were 66 and 4.7 $\mu \text{M}$ for SWV and CA, respectively. Furthermore, a self-powered feature is demonstrated, in which the device can be powered by harvesting energy from ambient light.