Molecularly imprinted orthophenylenediamine with Ti₃C₂T_xMXene-based biosensor for sensitive detection of bilirubin

In this study, bilirubin (BR) is detected by using a novel molecularly imprinted electrochemical sensor based on a Ti(3)C(2)T(x)MXene-modified ITO electrode. First, Ti(3)C(2)T(x)MXene is synthesized by chemical etching and deposited at the ITO electrode surface by drop casting. After that, ortho-phenylenediamine (o-PD) as monomer is electropolymerized in the presence of a sodium acetate buffer solution containing the BR template to prepare BR-imprinted electrode. Field emission scanning electron microscopy (FESEM), x-ray diffraction and UV-visible absorption spectroscopy confirms the MXene synthesis. The molecular imprinted polymer (MIP) formation at the electrode is confirmed by electrochemical methods such as differential pulse voltammetry, electrochemical impedance spectroscopy, and cyclic voltammetry, and FESEM. The linearity range, limit of detection and the limit of quantification are calculated as 0.1 mg/dL to 20 mg/dL, 0.002 mg/dL, and 6.6 mg/dL respectively. Stability and reproducibility are also reported for the prepared MIP sensor.