An All‐Soft Wearable Electrochemiluminescence Chip for Sweat Metabolite Detection

Wearable sensors are transforming real-time, non-invasive health monitoring. Despite considerable advances in electrochemical and optical sensing modalities, challenges remain in achieving reliable, sensitive, and cost-effective detection of sweat metabolites due to the variable chemical composition of sweat and difficulties in device integration. Electrochemiluminescence (ECL) offers an attractive alternative for wearable sensing due to its high sensitivity and ease of integration without complex circuitry or external light sources. However, ECL is rarely used in wearable formats due to challenges in flexible electrode and stable luminophore development. Here, we present a fully soft, skin-conformable ECL chip for sweat metabolite monitoring, integrating a laser-patterned closed bipolar electrode array, a microfluidic sweat collector, and deep eutectic solvent-based ionogels as robust ECL emitters. This architecture separates sensing and reporting zones, effectively reducing signal interference from complex sweat matrices, while the ionogels enhance signal stability and device flexibility, enabling prolonged on-skin operation. Taking glucose as a model analyte, we demonstrate specific and direct ECL readout by integrating a specific enzymatic reaction with a linear range from µm to mm. The device accurately captures postprandial glucose changes, with a per-chip cost of $0.106, demonstrating its great potential for real-time metabolic tracking in personalized health monitoring or clinical diagnosis.