Dual-readout lateral flow immunoassay for detection of amphenicols using intensified colorimetric-fluorescent carbon...

Conventional lateral flow immunoassays (LFIA) employing gold nanoparticles as probes suffer from insufficient sensitivity and poor accuracy in detecting amphenicols in food. Developing a dual-readout LFIA with fluorescence and colorimetric signals can significantly enhance its performance. Herein, fluorescent carbon dots were encapsulated into SiO₂ nanospheres to obtain the SiO₂/CDs nanocomposites with a quantum yield of 81.26 %. The encapsulation enhances the signal intensity and prevents fluorescence quenching of carbon dots. Surface modification of SiO₂/CDs with polydopamine (PDA) enables efficient antibody conjugation. The strong light absorption capacity of PDA also endowed the nanocomposites with good colorimetric signals. The SiO₂/CDs@PDA-based LFIA showed 5-fold and 71-fold improvements in chloramphenicol detection using colorimetric and fluorescent modes, compared to conventional LFIA. The quantitative detection limits were 1.03-1.54 ng/g and 0.1-0.78 ng/g in colorimetric and fluorescent mode for amphenicols in chicken. The proposed LFIA offers a rapid, accurate, and reliable method for food safety monitoring.