3.4 Cellular localization of UCNP-based nanocarrier in tumor
cells
The efficiency of PDT treatment is highly dependent on PS cellular
uptake and accumulation in malignant tissues (Nawalany et al., 2009).
The
fate of the UCNP-based carrier in tumor cells were investigated using
confocal
laser scanning microscopy. As shown in Figure 7, the confocal microscopy
assay was based on the red
autofluorescence
of Pha, and the blue fluorescence from DAPI bound to the nucleus, and
F-actin in the cytoplasm stained by Alexa Fluor 488 phalloidin.
For MCF7 cells treated with free Pha, the red fluorescence signal from
Pha detected in MCF7 cells was quite weak (Figure 7B). On the other
hand, UCNP-based Pha carriers, FA-PEAH-UCNPs-Pha and
CH3-PEAH-UCNPs-Pha, showed higher red fluorescence Pha
signal compared with the free Pha sample. Especially, after
FA-PEAH-UCNPs-Pha treatment, MCF7 cells produced strong red fluorescence
from Pha around the nucleus and at the inner part of the cells,
indicating that
Pha
molecules were effectively internalized into the MCF7 cells (Figure 7D).
The results indicate that the UCNP-based Pha carrier improved the Pha
water solubility, and FA ligands could effectively enhance the cellular
uptake of Pha molecules into MCF7 cells by an active targeting effect.
These
strong
fluorescence signals from Pha could be also used to clearly understand
the dynamics of signal transduction in the intracellular networks and in
diagnostics.