Design of an electrochemical sensor based on molecularly imprinted polymers for sensitive and selective detection of the JAK inhibitor baricitinib

Baricitinib (BAR), a selective JAK1/JAK2 inhibitor, is a widely used drug in the treatment of inflammatory and immune-related disorders, including rheumatoid arthritis and COVID-19 complications. However, due to its narrow therapeutic index and pharmacokinetics, precise therapeutic drug monitoring is necessary. While HPLC-based methods are commonly employed, they tend to suffer from high costs, lengthy analysis, and complex procedures. Electrochemical methods offered a promising alternative, but selectivity remains a challenge in biological matrices. To address this, a highly sensitive and selective molecularly imprinted polymer (MIP)-based electrochemical sensor (poly(Py-co-2-TBA)/BAR@MIP/GCE sensor) for BAR detection was developed in this study. The sensor was fabricated using the electropolymerization (EP) technique on a glassy carbon electrode, utilizing 2-phenylboronic acid (2-TBA) as the functional monomer and pyrrole (Py) to provide both conductivity and stability to the polymeric structure. Key parameters, including template-to-monomer ratio, polymerization cycles, and rebinding time, were optimized. Electrochemical and surface morphology characterizations were performed using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and scanning electron microscopy (SEM). The sensor demonstrated excellent selectivity for BAR, even in the presence of structurally similar compounds. The developed MIP-based sensor presents a cost-effective, rapid, and reliable tool for BAR monitoring, supporting personalized dosing and improved therapeutic outcomes.