Chemiluminescence immunoassay based on anti-MRGPRX2&HRP@ZIF-8 and its application in the clinical detection of chronic spontaneous urticaria

The immunoassay methods, stand as the gold standard in biomedicine, are widely used in diagnostics. However, they often encounter inherent limitations in practical applications, such as the poor stability of enzymes and antibodies, and the laborious process of preparing enzyme-antibody conjugates through covalent bonding. Mas-related G-protein-coupled receptor X2 (MRGPRX2) has been identified as a blood-based diagnostic biomarker for chronic spontaneous urticaria (CSU). In this study, a bifunctional enzyme-labeled antibody (anti-MRGPRX2&HRP@ZIF-8) was successfully constructed by integrating horseradish peroxidase (HRP) into ZIF-8 during its synthesis, followed by adsorption of anti-MRGPRX2 onto the surface of HRP@ZIF-8. The resulting anti-MRGPRX2&HRP@ZIF-8 complex not only preserved its antigen-capturing capability but also exhibited improved stability. The established chemiluminescence immunoassay (CLIA) method based on anti-MRGPRX2&HRP@ZIF-8 demonstrated enhanced stability and achieved a lower detection limit (1.035 ng/mL) compared to conventional enzyme-linked immunosorbent assay (ELISA) method. Furthermore, MRGPRX2 was successfully detected in serum samples by the established method, demonstrating its suitability for the diagnosis of CSU in real clinical samples. Consequently, this study presented a promising approach for simplifying the preparation of enzyme-antibody conjugates and highlighted the potential of metal-organic framework (MOF)-based composites in biomedical applications.