Electrochemical Sensing of Phenylalanine using Polyaniline-Based Molecularly Imprinted Polymers

Polyaniline (PANI)-based molecularly imprinted polymers were investigated for their efficacy in sensing phenylalanine (Phe) when fabricated on both glassy carbon electrode (GCE) and indium tin oxide (ITO) sheets. This study highlights the superior performance of PANI-MIP/ITO over PANI-MIP/GCE for sensing Phe, with clear and distinct redox responses. Molecular computation helps to understand the interaction mechanism between PANI and Phe, where molecular crowding, aggregated clusters, hydrogen bonding, and π-π stacking facilitate stable interactions. We tested the specificity of Phe sensing by PANI-MIP with different amino acids such as cysteine, tryptophan, and tyrosine as well as organic molecules such as ascorbic acid, allantoin, sucrose, and urea, confirming its remarkable electrochemical efficiency. The oxidation response curve yielded a limit of detection of 4.88 μM and a limit of quantification of 16.3 μM, comparable to or better than earlier reported sensors. This work demonstrates the promise of MIP-based electrochemical sensing. It also lays the groundwork for future investigations into optimizing PANI-MIPs with nanocomposites to develop more selective and stable sensors.