This study investigates the fabrication of laser-scribed graphene (LSG) electrodes on polyimide substrates using a CO2 laser cutter for label-free L-Histidine detection in artificial sweat. Two-level full factorial and central composite designs were employed to optimize critical manufacturing parameters, including laser speed, power, and electrode width. Electrochemical characterization using cyclic voltammetry with K3FeCN6 demonstrated superior LSG electrode performance compared to standard glassy carbon electrodes, exhibiting a 702 ± 62% higher oxidation current peak at 0.56 mM K3FeCN6 in 0.1 M KCl. We successfully demonstrated the label-free electrochemical detection of L-Histidine in artificial sweat using these LSG electrodes. The results show a linear relationship (R2 = 0.987) between current peak and L-Histidine concentration within the 8.3 mM to 50 mM range, demonstrating high sensitivity towards L-Histidine. These findings highlight the potential of this optimized LSG electrode fabrication approach for developing high-performance, user-friendly, and disposable wearable biosensors for real-time and non-invasive health monitoring applications in sweat analysis.
García-Rodríguez et al. (Tue,) studied this question.