Ti3C2Tx MXene nanosheets, N-doped carbon dots and ionic liquid nanocomposite as a molecular imprinted polymer based electrochemical sensor for tau protein

Tau protein is a key biomarker for the onset and progression of Alzheimer’s disease. Its abnormal hyperphosphorylation and aggregation lead to neurofibrillary tangle formation, thereby disrupting neuronal function. The concentration of Tau in biological fluids correlates with disease stage and therapeutic response, making sensitive and selective detection crucial for early diagnosis and treatment monitoring. This work presents a molecularly imprinted polymer (MIP) based electrochemical sensor for the selective detection of Tau protein using a Ti₃C₂Tₓ MXene nanosheets, nitrogen doped carbon dot (NCD), and ionic liquid (IL) nanocomposite modified screen-printed electrode (SPE). A polydopamine based MIP layer was subsequently deposited to form an integrated recognition platform (MIP/MXene-NCD/IL/SPE). The Ti₃C₂Tₓ MXene provides a high surface area and excellent electrical conductivity, while the NCD and IL enhance functionalization and charge transfer within the polymer matrix. The MXene–NCD/IL nanocomposite was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV). The fabricated sensor exhibited a wide linear detection range from 10 to 300 pg/mL and a low limit of detection (LOD) of 1 pg/mL for Tau protein. The MIP/MXene-NCD/IL/SPE demonstrated superior electrochemical performance and a large specific surface area, resulting in enhanced signal amplification. Moreover, the sensor showed excellent stability, reproducibility, and selectivity against potential interfering biomolecules. Standard addition experiments in artificial human serum confirmed the reliability and practical applicability of the sensor. These results demonstrate that the developed sensor offers a sensitive, selective, and portable platform for Tau protein detection, with strong potential for real-time Alzheimer’s disease diagnosis and monitoring. This study further highlights the versatility of MXene‑carbon dot hybrids in advancing next-generation biosensing systems for precision neurodiagnostics.