A novel electrochemical biosensor for monitoring and sensitive detection of digoxin in serum samples using a combination of two-dimensional covalent organic framework as supporting materials and a boronate affinity-based surface molecularly imprinted polymer

Therapeutic drug monitoring (TDM) is a well-established clinical practice that involves measuring the concentration of drugs in blood or other biological fluids to optimize dosing regimens for patients. It is essential for medications characterized by narrow therapeutic windows, which denote the gap between the minimum effective concentration and the minimum toxic concentration of a drug. In this research, we present a novel approach for the selective and sensitive recognition of digoxin (DIG) using a combination of two-dimensional covalent organic framework (COF) as supporting materials and a boronate affinity-based surface molecularly imprinted polymer (MIP) polymerizing with 4-carboxyphenylboronic acid (4-CPBA) and methacrylic acid (MAA) for a double recognition of the sugar moiety of DIG and particular affinity for the template. The boronate affinity-based MIP biosensor exhibited strong affinity, high sensitivity, a wide linear range, low detection limit, and good reproducibility for DIG detection. Under optimal conditions, the biosensor demonstrated a linear range of 50 pM to 300 nM, with a calculated limit of detection (LOD) of 27.02 pM. Furthermore, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were performed for the analytic performance of the electrochemical biosensor (CPBA-MAA-MIP@COF/Pencil graphite electrode (PGE)) for various DIG drug dilutions.