Highly sensitive detection of a small molecule by a paired labels recognition system based lateral flow assay
Small molecules are difficult to detect by conventional gold lateral flow assay (GLFA) sensitively because the test system must satisfy the conflict requirements between enough signal intensity and limited antibody (Ab) amount. In this work, a paired labels recognition (PLR)-based biosensor was designed by utilizing the specific binding of Ab and secondary antibody (anti-Ab) to enhance signal intensity and reduce antibody amount applied in small molecule detection. The PLR amplification system is fabricated by self-assembling the common detection probe, Au-labeled Ab (Au-Ab), and the signal booster, Au-labeled anti-Ab (Au-anti-Ab). Benefiting from this, a powerful network structure can be generated to accumulate numerous gold nanoparticles (GNPs) and thus significantly strengthen the signal intensity of detection. Therefore, a lower Ab amount will be applied to offer adequate signal strength, and further, the limit of detection will be obviously downregulated due to the more effective competition reaction. Using furazolidone (FZD) as a model analyte, we achieve a detection limit of as low as 1 ng mL−1, which was at least fivefold improved over that of the traditional GLFA. Furthermore, the practicality of this strategy was certificated in five different food samples.
KeywordsLateral flow assay Gold nanoparticles Signal amplification Furazolidone Food analysis
This work was supported by the National Natural Science Foundation of China (No. 21675127, 31501560), the New Century Excellent Talents in University (NCET-13-0483), and the Fundamental Research Funds for the Central Universities (2014YB093, 2452015257).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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