Multiple-readout lateral flow immunoassay for the sensitive detection of nitrofurazone metabolites through ultrabright AIE-MOF coupled in-situ growth strategy

The multiple-readout capability of multimodal detection enhances the flexibility, reliability, and accuracy of lateral flow immunoassay (LFIA). The conjugation of two different metal-organic frameworks (MOFs) as a new-generation composite material offers extraordinary opportunities for developing multimodal LFIA. It is anticipated to compensate limitations of traditional single colorimetric signal LFIA and improve the analysis performance. Herein, an ultra-bright fluorescent AIE-MOF was proposed and coupled with an in-situ growth of Prussian blue (PB) nanoparticles strategy to obtain a novel multimodal signal tracer (AIE-MOF@PB). Thereafter, it was successfully applied to develop the multimodal LFIA platform for the detection of nitrofurazone metabolites. The synergy of AIE-MOF and PB endows AIE-MOF@PB with superb water dispersibility, robust fluorescence emission, brilliant colorimetric signal, marvelous photothermal conversion, and enhanced antibody coupling efficiency, all of which facilitate a highly sensitive triple-readout LFIA platform. The detection sensitivity improved by at least 5-fold compared with the colloidal gold-based LFIA. This work not only inspires the rational design of aggregation-induced emission luminogens (AIEgen)-based complex materials but also highlights the promising potential in flexible point-of-care applications.