A novel approach for glassy carbon electrode modification using In₂O₃-enhanced molecularly imprinted polymers for diclofenac detection

Unregulated trace pollutants such as pharmaceuticals and their metabolites pose serious environmental risks due to their persistence and poor biodegradability. Diclofenac, a widely used non-steroidal anti-inflammatory drug, exemplifies this problem and underscores the urgent need for highly sensitive analytical devices capable of detecting it at trace levels. Although electrochemical sensors have advanced, new materials and fabrication strategies are still required to achieve reliable, low-level detection. In this work, a novel material design strategy is introduced for fabricating hybrid molecularly imprinted polymer films on glassy carbon electrodes through the electropolymerization of methacrylic acid in the presence of indium oxide nanoparticles. The electropolymerization method offers a rapid and cost-effective route to produce stable molecularly imprinted polymer layers. The study focuses on establishing and optimizing the key stages of this fabrication pathway, including imprint formation and template removal, which is a critical step for creating accessible recognition sites. Morphological, spectroscopic, and electrochemical analyses indicate successful polymer growth, efficient template extraction, and enhanced charge transfer properties. The resulting hybrid MIP architecture exhibits highly sensitive diclofenac detection, reaching sub-nanomolar limits. These findings demonstrate the effectiveness of combining methacrylic acid-based imprinting with In₂O₃ semiconductor nanoparticles and provide a foundation for the development of next-generation electrochemical sensors using this material-oriented design strategy.