1. Colorimetric and Reverse Fluorescence Dual-Signal Readout Immunochromatographic Assay for the Sensitive Determination of Sibutramine
- Author
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Gui, Yun, Zhao, Yun, Liu, Pengyan, Wang, Yulong, Mao, Xinxin, Peng, Chifang, Hammock, Bruce D, and Zhang, Cunzheng
- Subjects
Analytical Chemistry ,Chemical Sciences ,Nanotechnology ,Bioengineering ,Chemical Engineering ,Materials Engineering ,Macromolecular and materials chemistry ,Physical chemistry ,Chemical engineering - Abstract
Later flow immunochromatographic assay has been widely used in clinical, environmental, and other diagnostic applications owing to its high sensitivity and throughput. However, most immunoassays operate in the "turn-off" mode for detecting targets of low molecular weight. The signal intensity decreases as the analyte concentration increases, which poses a challenge for achieving ultrasensitive detection at low concentrations and is counterintuitive to new users. In this work, a fluorometric immunochromatographic assay (FICA) is developed to simultaneously read "turn-on" fluorescent and "turn-off" colorimetric signals, where ZnCdSe/ZnS quantum dots act as fluorescence donors and gold nanoparticles (AuNPs) act as quenchers. The fluorescent signal (excitation/emission wavelengths of 365/525 nm) is positively correlated with analytes' concentration. Taking sibutramine (SBT) as the analysis target, the visual limit of detection for SBT reached 3.9 ng/mL, and the limit of Quantitation was 5.0 ng/mg in spiked samples. The developed FICA achieves a high sensitivity in SBT detection, which is much lower than that of the colloidal gold-based immunochromatographic assay. This dual-function detection mode has great potential to be used as a rapid on-site semiquantitative method, providing an alternative mode for the determination of low levels of target analytes.
- Published
- 2024