Graphene-Enabled Wearable for Remote ECG and Body Temperature Monitoring

This article presents a comprehensive study on the \nsynthesis, characterization, and integration of laser-synthetized \ngraphene-based materials in a wearable device for noninvasive \nphysiological monitoring. Laser-induced graphene (LIG) and \nlaser-reduced graphene oxide (LrGO) materials are synthesized \nand characterized under different techniques to analyze and \ncompare their structural and chemical properties, including \nscanning electron microscopy (SEM), micro-Raman spectroscopy, \nand X-ray photoelectron spectroscopy (XPS). These materials \nare used afterward for the fabrication of temperature sensors, \nmicro-supercapacitors (MSCs), and electrocardiogram (ECG) \nelectrodes. In particular, the temperature dependence of the \nelectrical conductivity of LrGO is exploited for the fabrication \nof temperature-dependent resistors with a sensitivity \nof −1.23 k ·◦C−1, which are used as body temperature sensors \nafter being encapsulated into polydimethylsiloxane (PDMS) to \nincrease their linearity and immunity to humidity changes. \nMoreover, both MSCs and ECG electrodes are developed by \nleveraging the highly porous structure of LIG, demonstrating a \ngood electrochemical and ECG acquisition performance. Furthermore, \na wearable device is designed and fabricated integrating \nthese graphene-based components in a rigid-flex printed circuit \nboard (PCB) together with a Bluetooth low energy (BLE) \nmicrocontroller, thus enabling the wireless transmission of the \nphysiological data to external monitoring devices. The power \nconsumption has been optimized for extended battery life, allowing \ncontinuous monitoring over prolonged periods. Overall, this \nstudy demonstrates the feasibility and effectiveness of integrating \ngraphene-based materials into real wearable applications.