Bio-Rad Bio-Plex Pro™ Human Cancer Biomarker Assays - Manual (Page 4)

Principle
Technology
The Bio-Plex
® suspension array system is built upon the three core
elements of xMAP technology:
n
Fluorescently dyed microspheres (also called beads), each with a distinct
color code or spectral address to permit discrimination of individual tests
within a multiplex suspension. This allows simultaneous detection of more
than 100 different types of molecules in a single well of a 96-well microplate
n
A dedicated flow cytometer with two lasers and associated optics to
measure the different molecules bound to the surface of the beads
n
A high-speed digital signal processor that efficiently manages the
fluorescence data
Assay Format
Bio-Plex Pro
™ human cancer assays are essentially immunoassays
formatted on magnetic beads. The assay principle is similar to that of
a sandwich ELISA (Figure 1). Capture antibodies directed against the
desired biomarker are covalently coupled to the beads. Coupled beads
react with the sample containing the biomarker of interest. After a series
of washes to remove unbound protein, a biotinylated detection antibody
is added to create a sandwich complex. The final detection complex is
formed with the addition of streptavidin-phycoerythrin (SA-PE) conjugate.
Phycoerythrin serves as a fluorescent indicator, or reporter.
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