Dual-readout lateral flow immunoassay for detection of amphenicols using intensified colorimetric–fluorescent carbon dots nanocomposite

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 SiO 2 nanospheres to obtain the SiO 2 /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 SiO 2 /CDs with polydopamine (PDA) enables efficient antibody conjugation. The strong light absorption capacity of PDA also endowed the nanocomposites with good colorimetric signals. The SiO 2 /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.