A nanozyme-based enzyme-linked immunosorbent assay method for the detection of MRGPRX2 in human peripheral blood serum

Background Mas-related G-protein-coupled receptor X2 (MRGPRX2) is critical for mast cell degranulation and pseudo-allergic reactions. Detecting MRGPRX2 in human peripheral blood serum is essential for studying mast cell-mediated disorders like chronic spontaneous urticaria (CSU), asthma, and atopic dermatitis. While enzyme-linked immunosorbent assay (ELISA), known for sensitivity and specificity, is limited by the instability of enzymes and antibodies, hindering cost-effectiveness and robustness. Metal-organic frameworks (MOFs) with mild synthesis conditions, excellent biocompatibility, and peroxidase-like catalytic activity were selected as alternatives to conventional enzymes, thereby offering a promising approach to enhance the stability and efficiency of ELISA. Results In this study, Cu-MOF, which exhibiting excellent biocompatibility and catalytic performance, was selected as an alternative to traditional enzymes. The in-situ synthesized anti-MRGPRX2@Cu-MOF retained its antigen recognition capability and enzyme-like catalytic activity across a broad pH range (3–10) and at elevated temperatures (45°C-85°C). The established ELISA method demonstrated a detection limit of 1.660 ng/mL for MRGPRX2. The method exhibited satisfactory accuracy, with recovery rates ranging from 97.95% to 108.68% for intra-assay assessment and from 95.18% to 110.66% for inter-assay assessment. The precision was also acceptable, showing intra- and inter-assay coefficients of variation below 13.94% and 14.41%, respectively. The concentration of MRGPRX2 antigen in human serum was successfully detected using the established ELISA method based on anti-MRGPRX2@Cu-MOF. This method is characterized by its low cost, high stability, and excellent recovery rates and precision. Significance The established ELISA method based on the nanozyme-labeled antibody demonstrated favorable recovery rates and precision for detecting the CSU biomarker MRGPRX2. This method offers several advantages such as cost-effectiveness and the capability for visual result interpretation, making it a promising candidate for future applications in portable detection devices and clinical diagnostics.