Improved performance of lateral flow immunoassays for alpha-fetoprotein and vanillin by using silica shell-stabilized gold nanoparticles
The sensitivity of lateral flow assays (LFA) was increased 30-fold by making use of spherical core-shell gold-silica nanoparticles (AuNP@SiO2 NPs). They can be prepared by silylation of surfactant stabilized AuNPs. The AuNP@SiO2 NPs are highly stable and can be used to label antibodies at virtually any concentration. The detection limit of an LFA for alpha-fetoprotein (AFP) can be decreased from 10 ng·mL−1 to 300 pg·mL−1 which makes it comparable to an enzyme-linked immunosorbent assay. To demonstrate the applicability to an immunoassay, a sandwich assay was developed for vanillin by covalent modification of the AuNP@SiO2 NPs with antibody. By using the method, vanillin can be detected visually in milk powder samples in concentrations as low as 100 ng·g−1. With unique optical property and great stability, this AuNP@SiO2 endows great potential in biosensing applications.
KeywordsCore-shell gold nanoparticle AFP Vanillin Lateral flow assay
This work was supported by the National Natural Science Foundation of China (81602608, 21402204 and 31671933, 81703333), Nanshan Scholar Program of Guangzhou Medical University (B185006006008 and B185006006009), Natural Science Foundation of Guangdong (020204003).
Compliance with ethical standards
The author(s) declare that they have no competing interests.
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