Hierarchical Nanogold Labels to Improve the Sensitivity of Lateral Flow Immunoassay

Kseniya Serebrennikova,Jeanne Samsonova,Alexander Osipov

doi:10.1007/s40820-017-0180-2

Kseniya Serebrennikova, Jeanne Samsonova + Show 1 more

Open Access

https://doi.org/10.1007/s40820-017-0180-2

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Abstract

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 fivefold 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 the sensitivity 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).

Highlights

The growing interest in the rapid detection of various biologically active substances has necessitated the need for the development of quick methods of analysis
The specific antibodies were immobilized in the test zone of the analytical membrane, and the conjugate pad was impregnated with the paired detection antibodies labeled with gold nanoparticles
No increase in the antibody consumption was observed with hierarchical nanoparticles such as gold nanopopcorns (GNPNs)

Summary

Introduction

The growing interest in the rapid detection of various biologically active substances has necessitated the need for the development of quick methods of analysis. Lateral flow immunoassay (LFIA), one of the most common express methods of analysis, offers advantages such as a short analysis time, long-term stability of test strips, ease of use, and cost-effectiveness, resulting in the expansion of its applications in different fields. LFIA is performed on membrane-based strips with pre-immobilized immunoreagents that are activated upon the flow of liquid samples. Despite the advantages of LFIA, some of the rapid tests lack the desired sensitivity and quantitative accuracy. A few approaches have been used to improve LFIA detection sensitivity such as the development of new labels with an detectable signal and the use of suitable readout techniques [3, 4]

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