Molecularly Imprinted PEDOT/CuNi-MOFs Nanosheet Arrays/3D Graphene Foam for Highly Selective and Sensitive Electrochemical Detection of Levodopa

Abstract

Levodopa (LD) is the gold-standard drug for the treatment of Parkinson’s disease and its highly sensitivity and selectivity detection is essential for effective treatment and improved patient outcomes. Herein, a simple one-step hydrothermal method is used to in situ grow CuNi-MOFs nanosheet arrays (NSAs) on three-dimensional graphene foam (3D GF). Density functional theory (DFT) simulations are employed to screen 3,4-ethylenedioxythiophene (EDOT) as the functional monomer and predict molar ratio of LD/EDOT. Guided by both simulation predictions and experimental results, the molecularly imprinted PEDOT layer is electropolymerized on the CuNi-MOFs NSAs/3D GF, which is used as an electrode for detection of LD. Furthermore, DFT simulation results confirm the effective adsorption of LD on the surface of PEDOT/CuNi-MOFs. The molecularly imprinted PEDOT layer improves the selectivity of the electrode for LD and achieves electrochemical signal amplification. Meanwhile, the CuNi-MOFs NSAs provide abundant active sites and the highly conductive 3D GF facilitates rapid electron transfer, thereby endowing the molecularly imprinted electrode an excellent selectivity, high sensitivity (2.676 μA·μM-1·cm-2) and low detection limit (0.026 µM). It also shows a good repeatability (RSD=2.06%), long-term stability (96.8% over 15 days) and fabrication reproducibility (RSD=1.56%). This electrode is used for the detection of LD in diluted serum samples and demonstrates promising prospects for clinical application.

Keywords: Parkinson's disease, molecularly imprinted conductive polymers, levodopa, 3, 4-ethylenedioxythiophene, CuNi-MOFs, 3D GF