Biomedical Engineering Reference
In-Depth Information
Fig. 19
Representative two-photon luminescence image (800 nm excitation) of MCF-7 cells
with internalized C-dots. Adapted from Cao et al., with permission from American Chemical
Society. Copyright 2007
lines, HeLa cells (human cervical cancer cell lines) and C6 cells (rat glioma cell
lines) and normal healthy cells, CHO cells (Chinese hamster ovary cell lines) were
selected. TTA1-C-dots exhibited higher targeting efficiency compared with SH-gC-
dots in HeLa and C6 cells. Increased fluorescence emission intensity for HeLa and
C6 cell lines treated with TTA1-C-dots indicated enhanced targeting with respect to
the SH-gC-Dots. However, in CHO cells, no detectable difference in fluorescence
intensity was observed between TTA1-C-dots and SH-gC-dots (Lee et al. 2013).
Song et al. (2012) reported the synthesis of folic acid conjugated fluorescent car-
bon nanodots (C-dots-FA), which are endocytosible by the overexpressed folate
receptor (FR) molecule. The assembly was able to distinguish folate positive HeLa
cancer cells from folate negative MCF-7 cancer cells. Additionally, HeLa cells pro-
duced bright fluorescence in comparison to normal NIH-3T3 cells due to lower
expression of FR receptor in normal cells, resulting in lesser uptake of C-dots-FA.
This clearly indicates that the C-dots-FA system could discriminate FR-positive
cancerous cells from normal cells. The above reported studies highlight that C-dots
are amenable to various cell imaging applications without the use of any compli-
cated protocols.
4.1.2 In Vivo Imaging
C-dots have exhibited the same or even better performances for in vivo imaging
in mice models compared to commercially available CdSe-ZnS QDs for optical
imaging applications (Cao et al. 2012). The use of C-dots and C
ZnS
-dots passi-
vated by PEG1500N for in vivo mice imaging was first ever reported by Sun's
group (Fig.
20
). Upon subcutaneous injection, mice exhibited bright emissions
upon excitation of 470 and 545 nm due to uptake of C-dots and C
ZnS
-dots.
