Trends of Bead Counting-Based Technologies Toward the Detection of Disease-Related Biomarkers

Fan, Wenjiao; Liu, Dou; Ren, Wei; Liu, Chenghui

doi:10.3389/fchem.2020.600317

Cited by 3 publications

(1 citation statement)

References 42 publications

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“…The digital assay, as a highly sensitive single-molecule detection technique, has attracted more and more attention in the analysis of ultralow concentration samples. − The main principle of the digital assay is to stochastically load the target molecules into microreactors in the way of “0” or “1”. Then, a signal amplification reaction (such as enzyme amplification) is carried out in the microreactor containing a single target molecule to generate a signal that can be distinguished from the microreactor without a target molecule.…”

Section: Introductionmentioning

confidence: 99%

A Facile Strategy for Multiplex Protein Detection by a Fluorescent Microsphere-Based Digital Immunoassay

Gong,

Tan,

Shan

et al. 2024

Anal. Chem.

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The digital immunoassay is a highly sensitive detection technique based on single-molecule counting and is widely used in the ultrasensitive detection of biomarkers. Herein, we developed a fluorescent microsphere-based digital immunoassay (FMDIA) by employing fluorescent microspheres as both the carriers for immunoreaction and fluorescent reports for imaging. In this approach, the target protein in the sample was captured by fluorescent microspheres to form a biotin-labeled sandwich immunocomplex, and then, the fluorescent microspheres containing the target protein molecules were captured by adding streptavidin-coated magnetic beads (SA-MBs). By counting the proportion of fluorescence-positive magnetic beads, the concentration of the target protein can be precisely quantified. As a proof of concept, α fetoprotein (AFP) and human interleukin-6 (IL-6) were used to assess the analytical performance of the proposed FMDIA, and limit of detection (LOD) values of 21 pg/mL (0.30 pM) and 0.19 pg/mL (7.3 fM) were achieved, respectively. The results of AFP detection in serum samples of patients and healthy people were consistent with the reference values given by the hospital. Furthermore, by adding fluorescent microspheres of various colors for encoding, the proposed FMDIA can easily realize the simultaneous detection of multiple proteins without the need to introduce multiple modified magnetic beads. This multiplex protein detection strategy, in which the reactions are first carried out on the fluorescent microspheres and then magnetic beads are used to capture the fluorescent reporters containing the target molecules, provides a new idea for digital assays.

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