Biomimetic electrochemical sensor for the highly selective detection of azithromycin in biological samples

A highly selective and sensitive molecularly imprinted polymer (MIP)-based electrochemical sensor was fabricated for the determination of azithromycin, a broad-spectrum macrolide antibiotic, from various biological samples (urine, tears, plasma). The reversible boronate ester bond-mediated, thin (similar to 75 nm) MIP-based bio-mimetic recognition layer was electrodeposited in non-aqueous media onto the surface of a glassy carbon electrode (GCE). The surface morphology and the analytical performances of the developed sensor were assessed by scanning electron (SEM) and atomic force microscopy (AFM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). By employing an indirect electrochemical detection in the presence of 10 mM ferro/ferricyanide as redox probe, the sensor exhibited a very wide dynamic range (13.33 nM-66.67 mu M), with an estimated detection limit in the subnanomolar range (0.85 nM azithromycin). The simple to construct sensor demonstrates reusability and good shelf-life, exhibiting remarkable selectivity over a wide number of structurally related and non-related antibiotics, commonly associated drugs and endogenous compounds.