A ratiometric electrochemical sensor based on molecular imprinting for highly selective detection of HVA

Homovanillic acid (HVA), the principal metabolite of dopamine, serves as a critical biomarker for central nervous system function. Its concentration fluctuations hold significant diagnostic and therapeutic monitoring value for neurological disorders including Parkinson's disease and schizophrenia. This study developed a highly selective molecularly imprinted electrochemical sensor fabricated through electropolymerization of pyrrole and 3-aminophenylboronic acid (APBA) on carbon fiber electrodes to construct HVA-templated molecularly imprinted polymer (MIP) membranes. Following template removal by electrochemical cycling in sodium tetraphenylborate buffer (pH 9.18), HVA-specific recognition cavities were formed. Significantly, methylene blue (MB) was incorporated as an internal reference signal, enabling quantitative HVA detection through ratiometric measurement of MB and HVA oxidation currents, thereby effectively eliminating environmental interference and electrode variability. Experimental results demonstrated excellent linear response in the 0.5–290 μM range with a low detection limit of 0.173 μM. Compared to conventional methods, the sensor exhibits distinct advantages such as facile fabrication, cost-effectiveness, and superior selectivity. The developed system provides a reliable approach for clinical HVA detection with significant potential for neurological disease diagnosis and treatment monitoring.