Electrochemically patterned biomimetic polypyrrole integrating ZnO·CuO nanoleaves for picomolar acetylcholine detection in cancer and neurological disorders

Abstract

The critical role of non-neuronal acetylcholine (ACh) as a biomarker, driving cancer proliferation and signaling neurodegenerative decline, demands sensitive, non-enzymatic diagnostic tools for early detection. This work presents a highly innovative non-enzymatic electrochemical sensor for the direct, ultra-sensitive quantification of ACh. The sensor is engineered by electropolymerizing a molecularly imprinted polypyrrole (MIP) matrix, embedded with uniquely structured ZnO·CuO nanoleaves (NLs), onto a disposable pencil graphite electrode. Computational modeling at the DFT level reveals strong non-covalent interactions that create high-fidelity recognition sites for ACh within the polymer. Comprehensive characterization (XRD, FTIR, FESEM, micro-CT, DLS) validates the successful synthesis of the nanocomposite and the precise formation of imprinting cavities. The optimized sensor achieves an exceptional detection limit of 2.2 pM and a broad linear dynamic range from 100 pM to 100 mM, ranking it among the most sensitive ACh sensors reported to date. It exhibits outstanding selectivity against key interferents and reliably detects ACh in human serum samples with excellent recovery (98.0–102.2%). This highly sensitive, robust, and cost-effective MIP-ZnO·CuO NL platform demonstrates immense potential for point-of-care clinical diagnostics in oncology and neurology.