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Figure 6.11 Top: principle of the dual immunohistochemical detection of biomarkers
expressed by human breast cancer cells. Ab1¼anti-human ER mouse mAb. Ab2¼polyclonal
rabbit anti-human c-erbB-2 oncoprotein Ab. EuB1 and TbB2: Bottom: Luminescent assays of
ER and Her2/
neu
receptors expressed in a cancerous breast tissue section.
Redrawn with
permission from [83]. Copyright 2010 The Royal Society of Chemistry.
expressed by the nucleus and human epidermal growth factor receptors (Her2/
neu
)
expressed by the cell membrane. The relative concentrations of the two receptors are rele-
vant for deciding which therapy has to be applied to the patient. For the analysis, 4-mm
sections of formalin-fixed breast carcinomas are pressed against the microchannel and the
two markers are visualized by a dual indirect immunohistochemical luminescent assay
under time-resolved conditions, as illustrated in Figure 6.11. The two bioconjugates used
are a goat anti-mouse IgG antibody labelled with [Eu
2
(H
2
L20)
3
] (EuB1) and a goat anti-
rabbit IgG antibody labelled with [Tb
2
(H
2
L20)
3
] (TbB2). The first and simplest micro-
fluidic devices designed allowed the test to be completed in 20 min versus
>
2 h in the
hospital and using only one-fifth of the expensive reactants [83,84].
Another approach to selective immunohistochemical assays is to incorporate the lumi-
nescent helicates into silica nanoparticles (NP) decorated with linking groups. The photo-
physical properties of monodispersed [Eu
2
(L7)
3
]@SiO
2
and [Eu
2
(L7)
3
]@SiO
2
/NH
2
NPs
are reported in Table 6.1. Nanoparticles with NH
2
-decorated silica contain an average of
2380 molecules of helicates per NP and can be conjugated to avidin or to goat anti-mouse
IgG polyclonal antibody. The latter bioconjugate detects biotinylated 5D10 monoclonal
antibodies expressed by MCF-7 breast cancer cells and bright images of these cells are
obtained by time-resolved luminescence microscopy [48].
6.2.5.3 DNA Analysis
The emission intensity and lifetime of the [Eu
2
(L5)
3
] helicate are severely quenched by
molecules such as ethidium bromide (EB) and acridine orange (AO), which are selective
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