Biomedical Engineering Reference
In-Depth Information
10.3 Analytical Applications
Depending upon the distance and geometry, a metal surface can
result in the quenching of luorescence or its enhancement by
factors of up to 1000. As a result, luorophores on metal surface can
be employed in developing sensitive detection systems. In order to
make the systems practical, recognition molecules such as antibody,
enzymes, DNA, and ligands must be introduced. We now focus on
their applications in protein immunoassays, DNA analysis, cell
imaging, and metal ion detection.
10.3.1 Protein Immunoassays
Homogeneous and competitive luorescence quenching
immunoassays are sensitive for the analysis of proteins. One example
is the use of Au NP/polyelectrolyte-coated polystyrene particles
for the determination of the presence of biotin. Figure 10.7 shows
a schematic illustration of a competitive luorescence quenching
immunoassay using a suspension of Au NP/PE-coated latexes.
79
(C)
(B)
(A)
Figure 10.7
Schematic illustration of competitive immunoassays using
a suspension of Au NP/PE-coated latexes. (A) Fluorophore-
labeled antibodies are quenched before injection of analyte
(biotin). (B) Injection of analyte. (C) Fluorophore-labeled
antibodies luoresce after being competitively released by
biotin. Reprinted with permission from Ref. 79.
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