Wearable MXene-enhanced organic Bio-FET paper patch for glucose detection in sweat with pH and temperature calibration

This paper proposes the design of organic Bio-FET sensors using paper as a substrate. Three different wearable biosensors have been engineered for the non-invasive monitoring of sweat biomarkers. The proposed sensors, which have a field-effect transistor (FET) structure, contribute to an array that is flexible, bendable, affordable, disposable, and biocompatible. The approach of drawing Organic FETs (OFETs) on paper using a paintbrush could successfully make cost-effective sweat biochemical sensors (glucose and pH Sensors) and biophysical sensors (temperature-sensor) which are versatile and sensors for real-time health monitoring. PDMS, PEDOT: PSS, and sensitive materials have been used as the oxide layer, source/drain electrodes, and the FET channel, respectively. The wearable glucose sensor utilizes a composite of copper oxide (CuO), carboxyl-functionalized multiwall carbon nanotubes (MWCNT-COOH), and Ti₃C₂ MXene (Ti₃C₂ MXene/CuO/MWCNT) as the channel material in its FET structure, enhancing its sensitivity and performance. Additionally, Ti₃C₂ MXene/MWCNT and Ti₃C₂ MXene/rGO/MWCNT composites were employed in the pH and temperature sensors, respectively, to enhance their functionality and performance. The proposed Bio-FETs are fabricated in three different designs: resistive, side-gated and back-gated structures, and their responses are compared and discussed. Continuous health monitoring is achieved through a fully integrated, disposable wireless device that combines glucose, pH, and temperature sensing. The fabricated Bio-FET exhibits high sensitivity and promising reproducibility, stability, and repeatability. To enhance precision, the proposed glucose sensor has been calibrated using real-time temperature and pH measurements.