Anti-biofouling Ti₃C₂T_X MXene-holey graphene modified electrode for dopamine sensing in complex biological fluids

With the development of new methods for the medical diagnosis, electrochemical sensors have attracted increasing attention. However, biofouling on the surface of the sensor significantly decreases sensor performance, thereby limiting the application of electrochemical sensors in complex biological fluids. Given the urgent need for anti-biofouling electrodes, a sensor based on a glass carbon electrode (GCE) modified with Ti₃C₂T_X MXene and electrochemically reduced holey graphene (ERHG) was fabricated and demonstrated to have excellent electrochemical performance and anti-biofouling properties. ERHG provides abundant surface-active sites and imparts stability by hindering the agglomeration and oxidation of MXene. Furthermore, the excellent conductivity and hydrophilicity of MXene result in a high electron transfer rate and strong hydrophilicity. The MXene-ERHG/GCE sensor can detect dopamine with a wide linear range (0.2-125 μM) and a low detection limit of 0.044 μM in phosphate-buffer saline solution. Importantly, the hydrophilicity of MXene-ERHG reduces non-specific protein adsorption on the electrode surface, providing resistance to biofouling. After immersion in bovine serum albumin for 30 min, MXene-ERHG/GCE retained 85.90% of its initial peak current value, much higher than that of ERHG/GCE (17.75%). The MXene-ERHG/GCE sensor also showed good sensitivity for dopamine detection in serum and artificial cerebrospinal fluid (aCSF) containing bovine serum albumin. Moreover, MXene-ERHG/GCE exhibited excellent reproducibility and long-term stability in aCSF. The results demonstrate that MXene-ERHG/GCE has excellent anti-biofouling performance, and shows potential as an electrode material for application in biosensing.