Multifunctional au-DTNB-ag nanoparticles immunoprobes based on color-Raman properties for lateral flow immunoassay detection of Glycinin

Glycinin is a common food allergen, which may cause allergic shock in severe cases, thus posing a threat to public health. Therefore, rapid and accurate detection of glycinin is crucial. In this study, we synthesized AuAg core–shell nanoparticles loaded with the Raman reporter molecule 5,5′-dithiobis(2-nitrobenzoic acid) (DTNB), which provides both colorimetric and Raman signal capabilities. These nanoparticles were applied to colorimetric lateral flow immunoassay (CM-LFIA) and surface-enhanced Raman scattering-based lateral flow immunoassay (SERS-LFIA), respectively. The CM-LFIA achieved a visual limit of detection (LOD) of 1 ng/mL, while the SERS-LFIA exhibited a LOD of 40 pg/mL, with good linearity over the range of 1 ng/mL to 10⁴ ng/mL (R² = 0.997). Moreover, the quantitative SERS-LFIA demonstrated satisfactory performance in spiked food matrix samples, achieving acceptable recoveries of 82–88 % and RSD ranging from 4.88 % to 6.97 %.