Deployable NADPH-based electrochemical sensing for rapid assessment of G6PD deficiency via a graphene nanoplatelet-WS₂ nanocomposite electrode

Glucose-6-phosphate dehydrogenase (G6PD) is vital for maintaining cellular redox balance through the generation of NADPH in the pentose phosphate pathway. Given the global prevalence of G6PD deficiency and its association with hemolytic anemia, neonatal jaundice, and drug-induced oxidative complications, rapid and reliable assessment of enzyme activity is clinically important. Because NADPH production directly reflects G6PD function, sensitive quantification of NADPH provides an effective strategy for deficiency screening. To address this clinical need, a deployable electrochemical biosensor was developed using a screen-printed graphene electrode modified with a graphene nanoplatelet–WS₂ (GNPl–WS₂) nanocomposite. The synergistic nanohybrid interface enhances conductivity, increases electroactive surface area, and accelerates electron-transfer kinetics, leading to amplified anodic signals for NADPH oxidation. The platform was systematically optimized and thoroughly characterized to ensure robust analytical performance. Under optimal conditions, the sensor demonstrated a wide linear range from 5 μM to 3.5 mM and a low limit of detection of 1.01 μM. Importantly, the device offers rapid analysis (time-to-result <2 min), portability, and operational simplicity without complex fabrication or electrode regeneration. These features make the proposed deployable sensor a practical and promising tool for point-of-care and field-based evaluation of G6PD activity in biological samples, particularly in blood samples.