Nanomodification engineering facilitated efficient fluorescence quenchers for developing sensitive lateral flow immunoassay

The fluorescence-quenching lateral flow immunoassay (FQ-LFIA) with a "turn on" pattern has shown considerable superiority comparing with traditional LFIA. For sensitive FQ-LFIA, the synthesis of fluorescence quenchers exhibiting excellent optical properties is crucial. Herein, using nanomodification engineering, we synthesized APDCOF, which exhibited intense absorption (ε390 and ε630 = 15.22 and 15.97 mL mg−1 cm−1, respectively). APDCOF as a "specific" fluorescence quencher, for which its absorption peaks highly coincide with the excitation and emission peaks of the fluorescent microsphere, could occur both the primary and secondary internal filtering effects in response to excitation and emission light, respectively, emerging high quenching efficiency to orange aggregation-induced emission fluorescent microspheres. We employed APDCOF as a quencher to develop APDCOF-LFIA for detecting the carbamate pesticide carbofuran. Compared with a colloidal-gold-based colorimetric LFIA, APDCOF-FQ-LFIA demonstrated 50- and 5.3-fold improvements in the sensitivity of the naked-eye qualitative interpretation and quantitative detection, respectively. Overall, our study presented an efficient and "specific" fluorescence quencher prepared through nanomodification engineering, offering a perspective strategy for constructing high-performance reporters in LFIA.