UV-Crosslinked Ti₃C₂ MXene Composite Hydrogel for Selective Detection of Neurotransmitters

Detecting neurotransmitters in the system is critical to diagnosing nervous system diseases. Many studies have been reported to produce high-performance sensors for sensing dopamine. Among the various materials, 2-dimensional Ti₃C₂ MXene, which is highly conductive and electrochemically active, has been investigated to detect neurotransmitters including dopamine, uric acid, and serotonin. However, MXene oxidizes quickly in aqueous conditions, hindering MXene from being widely applicable for biosensing applications.<br/>Herein, we report a composite of MXene and poly (ethylene glycol) diacrylate (PEGDA), enabling selective detection of neurotransmitters. PEGDA is a porous, UV-cross-linkable material with a low degradation rate, protecting MXenes from oxidation in aqueous conditions. The composite thickness was easily controllable by changing UV irradiation time and the guide mold. Also, the composite structure was porous enough to assist small molecules diffused inside, facilitating electrochemical detection of neurotransmitters.<br/>Electrochemical detection of dopamine was confirmed via cyclic voltammetry (CV) and differential pulse voltammetry (DPV), confirming that the composite could detect dopamine in aqueous conditions up to 50 nM. The limit of detection (LOD) is estimated to be lower than 50 nM, suggesting out MXene composite hydrogel would be further applicable for detecting neurotransmitters sensitively but selectively.