Thin-Film Reference Electrodes for Fast-Scan Cyclic Voltammetry

Electrochemical sensors rely on reference electrodes (REs) to provide stable potential standards, ensuring accurate and reliable detection. The development of biocompatible, stable, and miniaturized REs to replace conventional Ag/AgCl electrodes is crucial for translating electrochemical sensing for human applications. This study evaluates the performance of thin-film electrodes made from gold (Au), platinum (Pt), poly(3,4-ethylenedioxythiophene)-polystyrenesulfonate (PEDOT:PSS), and platinum-iridium (Pt-Ir) as REs for fast-scan cyclic voltammetry (FSCV), a widely used technique for real-time neurotransmitter detection. Using dopamine (DA) sensing as a model platform, our results demonstrate that Pt-Ir electrodes provide the necessary stable potential, low drift, and high reproducibility for FSCV sensing, even at a reduced size of 0.1 mm × 0.1 mm. Additionally, Pt-Ir exhibited performance comparable to Ag/AgCl electrodes across various pH levels and in the presence of biofouling agents. These findings highlight Pt-Ir as a promising alternative RE, with strong potential for integration into miniaturized electrochemical sensors for both preclinical and clinical applications.