Biomedical Engineering Reference
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Raman reporter molecules and target-speciic antibody as described
in Fig. 11.8. Although SERS enhancement diminishes as the size of
particles decreases, it is still possible to generate detectable SERS
upon aggregation of relatively small NPs. As demonstrated in
Reference 67 which NPs labeled with a secondary antibody targeting
the β-adrenergic receptors are used to label mouse cardiac myocytes.
The authors carefully passivated the NPs and relied upon the
receptors-mediated aggregation to produce a detectable SERS signal.
Because these receptors are known to form signaling domains of
~140 nm in size which typically containing ~15 dimerized receptor
units, NP labeling allowed the authors to obtain a complete receptor
map on the cell surface.
(1). Fabrication of SERS probes
+
+
(2). Cell Labeling
AB
(3). SERS Detection
SERS
Signal
Excitation
Laser
Figure 11.8
Schematics representation of the SERS-based cell microscopy.
(1) SERS active probes are fabricated through co-labeling
of Raman reporter molecule, secondary antibody, and
passivation molecules. (2) Receptors on the cells are irst
labeled with primary antibody before being exposed to SERS
nanoprobes. (3) SERS detection of receptors. See also Color
Insert.
Figure 11.9A shows an optical image of HeLa cells expressing
the transmembrane domain of the platelet-derived growth factor
receptor (TM) which has been labeled with NPs co-functionalized
with a nitrile-reporter molecule and a target-speciic recognition
unit. The nitrile vibrational group uniquely falls in a spectroscopically
quiet region which enables its ease of detection. The SERS intensity
map shown in Fig. 11.9B revealed three SERS active sites marked
as I, II, and III. These SERS-active regions are further characterized
in SEM in Fig. 11.9C,D. The three observed SERS hot-sites are
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