Constructing an electrochemical sensor with screen-printed electrodes incorporating Ti₃C₂T_x-PDA-AgNPs for lactate...

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.