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M. Liu et al. / Carbohydrate Polymers 142 (2016) 38–44
Fig. 5. The Cell viability of TPE-CMS LPNs. HepG2 cells were incubated with different
concentrations of TPE-CMS LPNs for 8 and 24 h. It can be seen that the cell viability
value of HepG2 cells is still greater than 90% for 24 h incubation.
Fig. 4. PL spectra of TPE-CMS LPNs. It can be seen that the maximum excitation and
emission wavelength of the TPE-CMS LPNs was located at 488 nm.
further implied that TPE-CMS LPNs possess excellent water dis-
given the additional evidence for the formation of amphiphilic
AIE-active copolymers through the one-pot strategy. The lumines-
cent properties of TPE-CMS LPNs were examined using fluorescent
spectroscopy in detail (Fig. 4). The maximum emission wavelength
of the TPE-CMS LPNs was located at 488 nm (excitation wave-
length was set as 365 nm). Furthermore, the fluorescence excitation
wavelength was located at 390 nm (using 488 nm as the emission
wavelength). More importantly, we found that the emission wave-
length was not changed when TPE-CMS LPNs were excited using
different excitation wavelength. The emission behavior of TPE-
CMS LPNs is obviously different from that of the fluorescent starch
obtained by hydrothermal treatment and carbon quantum dots.
The above results implied that the emission fluorescence of TPE-
CMS LPNs is possible generated from the aggregation of TPE dyes.
Furthermore, the AIE properties of TPE-CMS LPNs were measured
using H2O and THF mixture with different volume ratio. As shown
in Fig. S3, the fluorescent spectra showed that the fluorescent inten-
sity of TPE-CMS LPNs was gradually increased as the volume ratio of
H2O to THF was increased from 1:9 to 9:1. These results implied that
TPE-CMS LPNs also exhibited obvious AIE properties. The abnor-
mal fluorescent properties make TPE-CMS LPNs very suitable for
biological imaging due to their AIE active properties. The fluores-
cence stability of TPE-CMS LPNs has also examined. As shown in
Fig. S4, the fluorescent intensity of TPE-CMS LPNs was slightly
decreased after they were continually irradiated by UV lamp for
1 h. the fluorescent intensity value of TPE-CMS LPNs is 3864 before
UV lamp irradiation. After 1 h irradiation, the fluorescent inten-
sity value was decreased to 3623. The excellent photostability of
thiocyanate can be conjugated with chitosan to fabricate the turn
on probes. They found that the AIE nanoprobes TPE-CS showed
obvious good photostability as compared with the FITC modified
chitosan (FCS) (Wang et al., 2013). These results suggested that AIE
dyes based nanoprobes could not only overcome the ACQ effect
of conventional organic dyes, but also obviously improved their
photostability. These advantages make AIE dyes based nanoprobes
very promising for long term biological imaging applications. The
fluorescence quantum yield (QY) luminescent materials is another
very important parameter for their biomedical applications. Here
we found that the QY of TPE-CMS LPNs is as high as 29.6% using
quinine sulfate as the reference dye. These above results clearly
demonstrated that TPE-CMS LPNs possess high QY and excellent
tions.
probes (Zhang et al., 2011). In this work, the cytocompatibility of
TPE-CMS LPNs was quantitatively determined using cell counting
kit-8 (CCK-8) assay (Qi et al., 2013; Yin et al., 2014a; Zhang, Hu, Li,
Tao, & Wei, 2012a; Zhang et al., 2012b, 2013c, 2015a). As shown
in Fig. 5, the cell viability values were gradually decreased as the
concentrations of TPE-CMS LPNs increased. Even the concentration
of TPE-CMS LPNs as high as 100 g mL−1, the cell viability value
of TPE-CMS LPNs is still greater than 90% for 24 h incubation. The
IC50 values of TPE-CMS LPNs were also calculated based on the
cell viability results. We demonstrated that the IC50 values of TPE-
CMS LPNs are 977.8 and 167.2 g mL−1, respectively. All the above
results suggested that TPE-CMS LPNs possess excellent biocompat-
ibility, which is very promising for biomedical applications.
Considered their high water dispersibility, strong fluorescence
of TPE-CMS LPNs was examined by CLSM observation. The HepG2
cells were first incubated with 20 g mL−1 for 3 h, and then the
cell uptake behavior of TPE-CMS LPNs were monitored by CLSM.
As shown in Fig. 6A, Strong blue-green fluorescence signal was
detected in the location of cells. The outline of cells can be eas-
ily discriminated. On the other hand, the areas with relative weak
fluorescence signals was also observed at the center of cells, that
were revolved by the areas with strong fluorescence signals. The
could be facilely internalized by cells and mostly distributed in
the cytoplasm. More importantly, we found that cells still adhered
to cell plate very well, and the cell morphology showed no obvi-
ous change (Fig. 6B), further implied that TPE-CMS LPNs are well
biocompatible with cells. All these result suggested that TPE-CMS
LPNs could be a great glycosylated bioprobe with the potential
prospect for biomedical applications. Previously, the preparation
linkage, polymerization and formation of dynamic bonds have been
developed. Various AIE-active polymeric nanoprobes have been
fabricated (Liu et al., 2014a; Lu, Zhao, Tian, Wang, & Shi, 2014;
Zhang et al., 2013h). However, to the best of our knowledge, only
limited reports have devoted for the fabrication of glycosylated