Therapeutic drug monitoring of meropenem in human serum using a sensitive four-electrode electrochemical biosensor for critically ill patients in intensive care wards.

Therapeutic drug monitoring of antibiotics in critically ill patients with sepsis remains challenging due to highly variable pharmacokinetics, increasing the risk of under- or overdosing. This paper presents a novel single-use tetrapolar electrochemical impedance spectroscopy (EIS) biosensor for the rapid detection of meropenem in human serum. The sensor is based on a gold microband electrode functionalised with a self-assembled monolayer, protein G and anti-meropenem antibodies to enable selective antigen capture and impedance-based quantification. The biosensor demonstrated sensitive detection of meropenem over a range of 1-100 μg/mL in phosphate-buffered saline and within clinically relevant concentrations (8-16 μg/mL) in spiked human serum, with the lowest measured concentration of 1 μg/mL. Binding specificity was validated using tandem mass spectrometry and immunocapture liquid chromatography-mass spectrometry. The total assay time was under 15 min. This platform represents a promising approach for rapid, bedside-compatible monitoring of meropenem. While the impedance results demonstrate the potential of the biosensor for therapeutic drug monitoring, further validation is required to establish its specificity, robustness, and performance in clinically relevant samples. Additional studies are also needed to evaluate its potential role in supporting antibiotic dose optimisation in sepsis management and intensive care settings.