Surface Engineering of Laser-Scribed Graphene Sensor Enables Non-Enzymatic Glucose Detection in Human Body Fluids

Contemporary devices for glucose monitoring predominantly rely on finger-pricked blood through an enzyme-catalyzed reaction. However, the enzymes are highly expensive, unstable, and require complex procedures for integration with the sensing matrix, rendering strategic replacement by nonenzymatic sensors. Here, a nonenzymatic glucose sensor is developed based on surface engineering of laser scribed graphene (LSG)-an immerging 3D patterned graphene-that combines binder-free, highly porous, conducting graphitic carbon network. An easy and green method is developed to engineer the LSG surface by conformal anchoring of copper oxide nanoparticles (CuO NPs) of optimized NP size for enhancing its catalytic efficacy. The device shows excellent nonenzymatic glucose sensing performance (0.4 V detection potential vs printed Ag/AgCI reference electrode, <0.2 s response time, 0.1 mu M detection limit, 1 mu M-S mM linearity, and high selectivity). Noteworthy, the device exhibits high stability and reproducibility for glucose in human body fluids (whole blood, serum, sweat, and urine). In addition, conformal transfer of LSG to commercial Scotch brand tape (LSG(ST)) enables wearability of the device on curvilinear body parts, exemplified through miniaturized devices monitoring glucose in sweat directly. These findings pave a new path for a comprehensive personalized healthcare strategy by accurate nonenzymatic detection of glucose from human body fluids.