20August2018

Nano-Micro Letters

Hierarchical Nanogold Labels to Improve the Sensitivity of Lateral Flow Immunoassay

Kseniya Serebrennikova1, 2, *, Jeanne Samsonova1, 2, Alexander Osipov1, 2

Abstract
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Nano-Micro Lett. (2018) 10: 24

First Online: 23 November 2017 (Article)

DOI:10.1007/s40820-017-0180-2

*Corresponding author. E-mail: ksenijasereb@mail.ru

 

Abstract

 


Fig. 1 Scheme of LFIA using gold nanoparticles as labels: (1) Sample pad, (2) Conjugate pad, (3) Test line, (4) Control line, (5) Absorbent pad

Lateral flow immunoassay (LFIA) is a widely used express method and offers advantages such as a short analysis time, simplicity of testing and result evaluation. However, an LFIA based on gold nanospheres lacks the desired sensitivity, thereby limiting its wide applications. In this study, spherical nanogold labels along with new types of nanogold labels such as gold nanopopcorns and nanostars were prepared, characterized, and applied for LFIA of model protein antigen procalcitonin. It was found that the label with a structure close to spherical provided more uniform distribution of specific antibodies on its surface, indicative of its suitability for this type of analysis. LFIA using gold nanopopcorns as a label allowed procalcitonin detection over a linear range of 0.5-10 ng mL−1 with the limit of detection of 0.1 ng mL−1, which was five-fold higher than the sensitivity of the assay with gold nanospheres. Another approach to improve the sensitivity of the assay included the silver enhancement method, which was used to compare the amplification of LFIA for procalcitonin detection. The sensitivity of procalcitonin determination by this method was 10 times better than that of the conventional LFIA with gold nanosphere as a label. The proposed approach of LFIA based on gold nanopopcorns improved the detection sensitivity without additional steps and prevented the increased consumption of specific reagents (antibodies).


 

Keywords

Lateral flow immunoassay; Gold nanosphere; Gold nanopopcorn; Gold nanostar; Silver enhancement; Procalcitonin

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