Ferrous Tungstate Nanomaterials with Excellent Enzyme-Mimicking Activity to Enhance Lateral Flow Immunoassay Sensitivity

Lateral flow immunochromatography (LFIA) with gold nanoparticles (AuNPs) is widely used in the biomedical field as a rapid and simple in vitro detection technique. However, the conventional AuNP-LFIA has limitations in sensitivity and detection range. In this study, nonprecious metal iron-based bimetallic FeWO4 nanomaterials with convenient and excellent enzyme-mimetic catalytic activities were synthesized by a one-pot hydrothermal method. Here, FeWO4 nanomaterials were combined with C-reactive protein (CRP) detection antibodies to form a novel signal-enhancing probe for the analysis of CRP. The probe further achieves significant signal amplification by catalyzing the oxidation reaction of 3-amino-9-ethylcarbazole in the LFIA assay, thereby improving the sensitivity and accuracy of the assay. The application of FeWO4-based LFIA improved the limit of detection of CRP to 19.38 ng/mL after catalytic amplification, which is approximately 30-fold lower than that of the conventional AuNP-LFIA method. In addition, the method demonstrated good stability and reproducibility, providing a promising and prospective strategy for the early diagnosis of inflammatory diseases.