“Two-step” signal amplification for ultrasensitive detection of dopamine in human serum sample using Ti3C2T -MXene

Two-dimensional transition-metal (Ti3C2Tx-MXene) carbide layered materials with versatile surface functional group have attracted huge interest in electrochemical sensing due to their excellent metallic conductivity, outstanding electrical and mechanical properties, high volumetric capacity, and flexibility to construct highly sensitive biosensors. Herein, we present a ultrasensitive molecular architecture for neuromolecules dopamine sensing using Ti3C2Tx-MXene multilayered materials. It was prepared through in situ polymerization of 4-APBA (4-aminophenyl boronic acid) with a scalable "two-step" approach. Additionally, its on-site application was realized by fabricating a label-free screen-printed carbon (SPC) electrode for electrochemical sensing of dopamine levels in buffer and human serum samples at the point-of-care testing (POCT). Importantly, the high specificity of Ti3C2Tx-MXene/4-APBA modification for SPC-electrode electrochemical sensing could be easily implemented with great signal drifting. As a proof of concept, this novel electrochemical sensor was found to be logically inexpensive and straightforward. It could selectively measure dopamine levels with a limit of detection (LOD) of 1.3 nM in PBS (pH 7.2) and, 1.9 nM in the human serum sample. It had a wide range of linear detection of dopamine concentrations of 40 to 500 nM, with a sensitivity of 0.0134 µA nM-1. This work paves a new path for 2D Ti3C2Tx-MXene/4-APBA modification for biomedical and biosensing applications in dopamine detection at nanomolar concentrations with high specificity, selectivity, sensitivity, stability, and reproducibility.