Conformal L012-Gold Nanoparticles/Laser-Induced Graphene Interfaces-Based Flexible Electrochemiluminescence Array for Multiplexed Detection of Sweat Metabolites

Electrochemiluminescence (ECL) holds promise for wearable multiplexed sweat sensing due to its high sensitivity, broad linear dynamic range, and inherent capacity for parallel signal acquisition through electrochemical-to-optical conversion. However, its advancement has been constrained by the lack of conformal ECL analytical interfaces capable of adapting to deformable skin while maintaining efficient charge transport and stable ECL output. Herein, we developed a conformal ECL analytical interface fabricated via a simple drop-casting strategy, comprising laser-induced graphene (LIG) integrated with L012-reduced gold (L012-Au) nanocomposite. The flexible, porous LIG, rapidly produced by laser direct writing (LDW), serves as a skin-adaptive scaffold, offering a conductive and conformal matrix for anchoring and interlocking L012-Au, thereby enabling efficient ECL generation under physiological conditions. This interface demonstrated excellent mechanical resilience, with ECL intensity remaining virtually unchanged after 100 cycles of bending and recovery. To enable multiplexed detection, the conformal ECL analytical interface was further developed into an array chip using programmable LDW technology. With spatially resolved functionalization of specific oxidases and integration with a smartphone for both power supply and imaging, the resulting imaging sensor enabled simultaneous detection of glucose and lactate, two representative and clinically relevant sweat constituents, with limits of detection below 1.0 μM and a linear range of 1-500 μM. The flexible sensor chip also demonstrated good mechanical stability under bending and reliable performance in real sweat samples. This work validates a strategy from flexible materials to system integration, laying the groundwork for the future development of wearable and multiplexed ECL sensing platforms.