Ti3C2Tx MXene/AuNPs-empowered microfluidic electrochemical sensor for simultaneous sensing of lactate and potassium ions in blood

The simultaneous monitoring of lactate and potassium ions (K⁺) in blood is critical for the management of critical conditions like crush syndrome, yet it remains a significant challenge. Herein, we present a novel integrated microfluidic electrochemical sensor for the dual-mode detection of these biomarkers. The sensor leverages a synergistic composite of Ti 3 C 2 T x MXene and electrodeposited gold nanoparticles (AuNPs) to create a highly sensitive sensing interface. The microfluidic chip, fabricated with polymethylmethacrylate (PMMA), incorporates two independent detection chambers functionalized with lactate oxidase (LOx) and a valinomycin-based ion-selective membrane, respectively. This design enables specific and parallel detection from a single sample. The fabricated sensor demonstrated excellent performance. In a KCl solution, the sensor exhibited a linear range of 1 μM to 10 mM and a low LOD of 1 μM. In the 1 × PBS configuration of lactate solution, the sensor showed a linear range of 10 μM to 16 mM and an LOD of 10 μM. When applied to the analysis of rat plasma samples, the sensor showed strong correlation with a commercial hematology analyzer, confirming its accuracy and practical utility. This work provides a promising platform for point-of-care testing, offering a fast, convenient, and reliable method for simultaneous biomarker monitoring.