22.2.2.4 Peptides
Oligopeptides have various functions; some could be used as NP production
templates, and others could be utilized as charged molecules for NP production,
especially homo-oligomers [35]. Small peptides are usually the type of drugs that
are incorporated into NPs. Many other peptides are utilized as targeting groups,
such as RGD [36], NC-1900, which is an active fragment analog of arginine
vasopressin [37], and hexa-L-aspartic acid, which targets bone tissues [38].
Oligopeptides have similar advantages to aptamers when used as targeting groups.
22.3 In Vitro, Ex Vivo, and In Vivo Multiplex Molecular
Imaging by SERS
22.3.1 SERS Nanoparticles (SERS NPs)
SERS NPs can cause a plasmonic effect that adsorbs molecules onto a noble metal
surface (gold or silver), enhancing the Raman signal as much as 10
14 -fold to 10
15 -
fold [39]. These NPs have multiplex capability and high sensitivity [40].
Furthermore, the low autofluorescence and photobleaching of SERS NPs can
increase the diagnostic accuracy in SERS NP-based imaging.
22.3.2 In Vitro Cell Analysis
The gold standard of identifying tumor cells has been histopathology based on
hematoxylin and eosin (H&E) staining in clinical study. However, this classification method provides no or little data about the cells’ chemical and immunologic
components.; So, Raman spectroscopy has the potential to complement H&E
staining. Raman spectroscopy’s high diagnostic value to identify tumor cells has
been proven over the years. Chan et al. [41] demonstrated sensitivity of more than
98% when they categorize hematopoietic immortalized cell lines as normal or
neoplastic through laser tweezers confocal Raman spectroscopy and principal
component analysis from the Raman spectra. The results showed that distinction
between normal and tumor cells could be quantified based on the differences of
DNA and protein concentration.
Although the variation in immortalized cell lines may have been lower than that
in potential samples from patients, the same group further verified that individual
leukemia cells could be identified in blood that were acquired from cancer patients
[42].
22 Molecular Imaging Using Radionanomedicine
417
Oligopeptides have various functions; some could be used as NP production
templates, and others could be utilized as charged molecules for NP production,
especially homo-oligomers [35]. Small peptides are usually the type of drugs that
are incorporated into NPs. Many other peptides are utilized as targeting groups,
such as RGD [36], NC-1900, which is an active fragment analog of arginine
vasopressin [37], and hexa-L-aspartic acid, which targets bone tissues [38].
Oligopeptides have similar advantages to aptamers when used as targeting groups.
22.3 In Vitro, Ex Vivo, and In Vivo Multiplex Molecular
Imaging by SERS
22.3.1 SERS Nanoparticles (SERS NPs)
SERS NPs can cause a plasmonic effect that adsorbs molecules onto a noble metal
surface (gold or silver), enhancing the Raman signal as much as 10
14 -fold to 10
15 -
fold [39]. These NPs have multiplex capability and high sensitivity [40].
Furthermore, the low autofluorescence and photobleaching of SERS NPs can
increase the diagnostic accuracy in SERS NP-based imaging.
22.3.2 In Vitro Cell Analysis
The gold standard of identifying tumor cells has been histopathology based on
hematoxylin and eosin (H&E) staining in clinical study. However, this classification method provides no or little data about the cells’ chemical and immunologic
components.; So, Raman spectroscopy has the potential to complement H&E
staining. Raman spectroscopy’s high diagnostic value to identify tumor cells has
been proven over the years. Chan et al. [41] demonstrated sensitivity of more than
98% when they categorize hematopoietic immortalized cell lines as normal or
neoplastic through laser tweezers confocal Raman spectroscopy and principal
component analysis from the Raman spectra. The results showed that distinction
between normal and tumor cells could be quantified based on the differences of
DNA and protein concentration.
Although the variation in immortalized cell lines may have been lower than that
in potential samples from patients, the same group further verified that individual
leukemia cells could be identified in blood that were acquired from cancer patients
[42].
22 Molecular Imaging Using Radionanomedicine
417