Non-invasive fingertip sweat biosensor for early kidney disease biomarker screening

Accurate, non-invasive monitoring of creatinine is essential for assessing kidney function, with elevated levels indicative of chronic kidney disease (CKD). Sweat creatinine serves as a promising biomarker for kidney health. Similarly, sweat glucose monitoring is critical for detecting metabolic imbalances, particularly in diabetic kidney disease (DKD). Simultaneous detection of these biomarkers is vital for early and effective kidney disease management. This study introduces a novel touch-based biosensing platform for real-time, non-invasive self-screening of creatinine and glucose in sweat. The platform utilizes Prussian blue-modified screen-printed carbon electrodes, enhanced with carboxylated multiwalled carbon nanotubes (MWCNTs–COOH) and enzyme mixtures, fabricated through a simplified one-step drop-casting process. A polyvinyl alcohol (PVA) hydrogel ensures efficient passive sweat collection. The biosensor demonstrates a wide linear detection range (20–1000 µM creatinine, 0.05–1 mM glucose), high selectivity against common sweat interferents, and strong correlation with standard blood assays, validating its potential for reliable, non-invasive kidney disease screening.