Point-of-care diagnostics for therapeutic monitoring of levofloxacin in human plasma utilizing electrochemical sensor mussel-inspired molecularly imprinted copolymer

Therapeutic drug monitoring is mandatory for drugs with narrow therapeutic index and is an integral part of the patient care standards, where drug concentration is measured in biological fluids to “personalize” patient’s dosage. In this work a disposable electrochemical sensor has been developed for Levofloxacin (LEV) determination in human plasma. The selected substrate was pencil graphite electrode (PGE). To enhance the sensor performance, the PGE has been modified with Au-NPs via electrochemical deposition. To achieve high selectivity towards levofloxacin, the PGE/Au-NPs electrode has been further modified with molecularly imprinted copolymer; poly(l-dopa)/poly(o-phenylenediamine), by anodic electropolymerization of the corresponding monomers. The Levodopa not only acts as a functional monomer but moreover, a substrate for mussel-inspired polymer. The sensor surface has been characterized using both scanning electron microscopy (SEM) imaging and X-ray photoelectron spectroscopy (XPS) to investigate the morphology and elemental composition of the modified PGE, respectively. To optimize the sensor performance, experimental variables were studied and tuned to improve the outcomes. The sensor has a linear response in two concentration windows (1.0 × 10−6–1.0 × 10−4 mol/L) and (1.0 × 10−4–1.0 × 10−2 mol/L) Levofloxacin, with a limit of detection of 4.62 × 10−7 mol/L. Selectivity, repeatability, and low manufacturing cost are some benefits of the proposed sensor. The sensor was successfully used to determine Levofloxacin in Tavanic® tablets and spiked plasma samples.