Molecularly imprinted polypyrrole-based POF dual sensor for dopamine detection exploiting plasmonic and voltammetric methods

This work introduces a dual-mode chemical sensor for the detection of dopamine. It exploits an electropolymerized molecularly imprinted polypyrrole (eMIP) on a surface plasmon resonance (SPR) D-shaped plastic optical fiber (POF) platform, where the gold nanofilm serves as both a plasmonic surface and a working electrode within a voltammetric cell. The eMIP deposition and template extraction were monitored in real-time by the variation in plasmonic resonance wavelength. A custom cell enables the detection of dopamine via SPR or differential pulse voltammetry (DPV), depending on the sample matrix and analyte concentration. The sensor's performance was thoroughly evaluated using both transduction methods, showing excellent sensitivity across a broad range, from picomolar to micromolar levels. Real biological samples, such as blood (analyzed via SPR) and urine (via DPV), were tested, highlighting the sensor's strong potential as a versatile and highly sensitive hybrid tool for dopamine monitoring.