Rapid detection of β-conglutin with a novel lateral flow aptasensor assisted by immunomagnetic enrichment and enzyme signal amplification

Abstract

A simple, rapid and economic lateral flow immunochromatographic assay (LFICA) was designed for ultrasensitive detection of β-conglutin. Instead of antibodies and gold nanoparticles (AuNPs) used in conventional LFICA, a cognate aptamer duo, binding to β-conglutin and Fe₃O₄@Au core-shell nanoparticles, was applied in this study. An enzyme signal amplification strategy was used to enhance sensitivity. In addition, a new magnetic enrichment strategy was employed to further enhance sensitivity of the assay, slowing down movement of the capture probe (i.e., Fe₃O₄@Au nanostructures) using an external magnetic field. The novel LFICA assay can be completed within 20 min and achieved a detection limit of 8 fM, a thousand-times lower than similar assays without magnetic focusing. Overall, our results demonstrated the potential for the proposed LFICA sensor in rapid detection of β-conglutin without any special analytical expertise or instrumentations.

Keywords: Aptamer; Food allergen; Lateral flow; Magnetic gold nanoparticles; β-Conglutin.