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

Conventional gold nanoparticles-based lateral flow immunoassays (AuNPs-LFIA) lack sensitivity. In this work, we developed a graphite-like carbon nitride-laden AuNPs (g-CN@Au) assisted LFIA to improve sensitivity for 17β-estradiol (E2) in foods. g-CN 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-CN@Au-based LFIA (g-CN@Au-LFIA). The lowest visual limit of detection (vLOD) of E2 is 0.5 ng mL for g-CN@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-CN@Au based LFIA for its application in food products.