Electrochemical detection of levodopa via integrated molecularly imprinted recognition and tyrosinase catalysis on MOF-derived CuCo@N-doped carbon nanosheet arrays/3D graphene foam.

Abstract

Levodopa (LD) is a primary therapeutic agent for Parkinson's disease, and accurately monitoring its concentration in blood is crucial for optimizing treatment regimens. Herein, an electrochemical sensing electrode integrating molecular imprinting with tyrosinase (TYR) catalysis is developed for sensitive and selective LD detection. First, CuCo-ZIF nanosheet arrays are grown in situ on three-dimensional graphene foam (3D GF) and converted into Cu/Co nanoparticle anchored N-doped carbon nanosheet arrays (CuCo@NCNSA/3D GF) by pyrolysis. Subsequently, a molecularly imprinted poly(3,4-ethylenedioxythiophene) (MI-PEDOT) layer is electropolymerized using LD as the template, followed by covalent immobilization of TYR. The electrode integrates the molecular recognition capabilities and electrochemical activity of MI-PEDOT with the enzymatic catalysis of TYR, achieving a sensitivity of 2.059 μA μM-1 and a limit of detection (LOD) of 0.016 μM for LD. In 50-fold and 100-fold diluted serum samples, LODs are 0.31 and 0.10 μM, respectively. For whole blood analysis, a polyacrylamide hydrogel (PAM-H) antifouling layer enables direct whole blood filtration, allowing quantitative LD detection over the range of 0-20 μM with a LOD of 1.0 μM. The PAM-H-assisted electrode maintains a stable response and enables reliable LD quantification in whole blood filtrates, highlighting their potential for the rapid analysis of complex biological samples and for use in point-of-care testing (POCT).

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