Constructing an electrochemical sensor with screen-printed electrodes incorporating Ti3C2Tx-PDA-AgNPs for lactate detection in sweat.

Sweat lactate levels are closely related to an individual's physiological state and serve as critical indicators for assessing exercise intensity, muscle fatigue, and certain pathological conditions. Screen-printed electrodes (SPEs) offer a promising avenue for the development of low-cost, high-performance wearable devices for electrochemical sweat analysis. The material composition of SPEs significantly impacts their detection sensitivity and stability. In this study, we designed a screen-printed carbon electrode (SPCE) modified with Ti₃C₂T_x Polydopamine (PDA), and silver nanoparticles (AgNPs) (Ti₃C₂T_x-PDA-AgNPs) for lactate detection in sweat. The accordion-like structure of Ti₃C₂T_x provides a large specific surface area and exceptional electrical conductivity. PDA, acting as both a reducing agent and binder, supports the in-situ formation of AgNPs on the Ti₃C₂T_x nanosheets. These AgNPs prevent the restacking of Ti₃C₂T_x layers, further improving conductivity. The sensor exhibited sensitivities of 0.145 μA mM^-1, with limit of detection (LOD) of 0.181 mM (S/N = 3) in phosphate-buffered saline (PBS), meeting the requirements for for sweat lactate detection. The sensor was integrated into a wearable micro-electrochemical platform paired with a custom Android application for real-time sweat analysis. Testing on human sweat demonstrated the platform's potential for practical fitness monitoring and healthcare diagnostics applications.