Graphite-like carbon nitride-laden gold nanoparticles as signal amplification label for highly sensitive lateral flow immunoassay of 17β-estradiol

Abstract

Conventional gold nanoparticles-based lateral flow immunoassays (AuNPs-LFIA) lack sensitivity. In this work, we developed a graphite-like carbon nitride-laden AuNPs (g-C₃N₄@Au) assisted LFIA to improve sensitivity for 17β-estradiol (E2) in foods. g-C₃N₄ nanosheets were applied as carriers, because of their excellent chemical stability, large surface areas and low-cost, loading large numbers of AuNPs to amplify signals and improve the overall response of g-C₃N₄@Au-based LFIA (g-C₃N₄@Au-LFIA). The lowest visual limit of detection (vLOD) of E2 is 0.5 ng mL^-1 for g-C₃N₄@Au-LFIA, which exhibit a significantly three-fold improved analytical performance compared with that of AuNPs-LFIA. Additionally, this method was successfully used to the detection of E2 in four spiked food samples, offering a great potential of the g-C₃N₄@Au based LFIA for its application in food products.

Keywords: 17β-estradiol; Food samples; Gold nanoparticles; Graphite-like carbon nitride; Lateral flow immunoassay; Signal amplification.