Li_2025_Anal.Chim.Acta_1376_344625

BACKGROUND: Sensitive detection of acetylcholinesterase (AChE) inhibitors is crucial for pharmaceutical screening, managing neurodegenerative diseases, and drug development. However, their therapeutic use is often limited by toxicity and side effects. Current detection methods for AChE inhibitors suffer from issues like low sensitivity, high cost, and interference from complex biological matrices. Therefore, there is a growing and urgent demand for sensitive, reliable, and cost-effective sensors that enable early diagnosis, accurate monitoring of drug efficacy, and personalized treatment plans in various clinical settings. RESULTS: In this work, a novel ratiometric electrochemical sensor was developed using Pd-modified MXene integrated with Prussian blue (PB) nanocomposites for AChE inhibitor detection. The Pd-modified MXene provides high electrical conductivity and abundant surface sites for nanoparticle immobilization, enhancing electron transfer and signal strength. Pd nanoparticles improve the electrocatalytic activity of the electrode, boosting electron transfer. PB acted as a redox mediator that oxidized thiocholine (TCh), the enzymatic product of AChE-catalyzed hydrolysis of ATCh, and was reoxidized to generate a stable redox potential serving as an internal reference. This enabled dual-signal ratiometric detection, improving accuracy and resistance to background interference. Using berberine as a model inhibitor, the sensor exhibited a linear range of 0.13-41 micromol/L and a detection limit of 10.0 nmol/L. The sensor demonstrated excellent reproducibility, retaining 93.1 % of its initial response after 28 days, and detected berberine in tablet and serum samples with high recovery, showing broad applicability. SIGNIFICANCE: This work highlights the synergistic effects of Pd-MXene and PB, offering a portable, cost-effective strategy for highly sensitive AChE inhibitor detection. The dual-signal ratiometric detection system enhances both sensitivity and accuracy, making it ideal for biomedical and pharmaceutical applications, with significant potential for early diagnosis and monitoring of neurodegenerative diseases.