Disposable electrochemical aptasensor based on surface group-engineered NH2-MXene/CNT nanocomposite for sensitive determination of immunoglobulin E in human serum

Despite the importance of immunoglobulin E (IgE) as a biomarker for allergy diagnosis, its trace-level detection in serum remains challenging. In this paper, a disposable electrochemical aptasensor was developed using a surface group-engineered NH 2 -MXene/CNT nanocomposite for sensitive IgE detection. To eliminate the adsorption of MXene on methylene blue (MB), NH 2 -MXene was synthesized by directed surface group modulation (-F → -OH → NH 2 ). Multi-walled carbon nanotubes (CNTs) were then incorporated to prevent aggregation of MXene lamellae, forming a conductive NH₂-MXene/CNT composite that improved specific surface area and electron transfer. Employing MB as an intercalating electrochemical reporter, the release of MB upon IgE binding generated a quantifiable current change (ΔI), which demonstrated a certain functional relationship with IgE concentration. The aptasensor achieved a linear detection range of 0.04–40 nM and a limit of detection (LOD) down to 29 pM, providing satisfactory selectivity and reproducibility. More importantly, the analysis of clinical serum samples demonstrated its utility in the clinical diagnosis of allergies. This work proposes a promising alternative for point-of-care allergy diagnostics. • Engineering MXene surface groups (-F → -OH → -NH 2 ) solved MB adsorption for aptasensing. • NH₂-MXene/CNT composite improved specific surface area and electron transfer. • A novel disposable electrochemical aptasensor was developed for IgE quantification. • The sensor showed excellent performance for IgE determination. • Utility and advantages of the sensor were validated in clinical human serum analysis.