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Digital Analysis With Droplet-Based Microfluidic for the Ultrasensitive Detection of β-gal and AFP

Songbai Tian, Zhen Zhang, Jinyang Chen, Mingyuan Du, Zheng Li, Hai Yang, Xinghu Ji, Zhike He

Talanta. 2018 Aug 15;186:24-28.

PMID: 29784356

Abstract:

In this study, we presented a digital analysis with droplet-based microfluidic, which was applied for the detection of β-galactosidase (β-Gal) and AFP. The β-Gal was quantified according to the Poisson Distribution in digital analysis with droplets containing β-Gal and fluorogenic substrate fluorescein di-β-D-galactopyranoside (FDG). In our method, the lowest concentration of β-Gal we could accurately detect was 5 fM. We found that the digital detection could be applied in quantifying protein biomarkers, take AFP for model sample. The AFP was detected through indirect detection with excess streptavidin-conjugated β-galactosidase (SA-β-gal) as signal tag. To be specific, firstly SA-β-gal was conjugated to biotin-labeled AFP antibody, and then the unbounded signal tag in the reaction solution was taken out for digital detection with droplet-based microfluidic. As a result, the AFP could be also indirectly quantified at an fM level through subtraction. This experimental result demonstrated that the indirect detection with droplet-based digital analysis was able to detect biomarkers at a low level with a few samples on an ordinary flow-focusing microfluidic chip.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP17817208 Fluorescein di(β-D-galactopyranoside) Fluorescein di(β-D-galactopyranoside) 17817-20-8 Price
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