Biomedical Engineering Reference
In-Depth Information
d
n
4
y
3
n
g
|
7
Figure 9.7
Illustration of shell crosslinking of DTX-loaded polymer micelles with
redox-labile
disulfide
crosslinks
and
triggered
release
of
DTX
by
intracellular GSH.
12
Wang et al.
13
synthesized an amphiphilic triblock copolymer of poly(e-
caprolactone)-block-poly(mercaptoethyl ethylene phosphate)-block-poly(ethyl-
ene glycol) (PCL-b-PPE
SH
-b-PEG), which could form CSC micelles with free
thiols in the shell as indicated in Figure 9.8. Crosslinking of the micelles within
the shell reduced their CMC and enhanced their stability against severe
conditions. The redox-sensitive crosslinkage allowed the facilitated release of
entrapped anticancer drugs in the cytoplasm in response to the intracellular
reductive environment. With enhanced stability during circulation after
administration, and accelerated intracellular drug release at the target site,
the biocompatible and biodegradable shell-crosslinked polymeric micelle was
proposed as a promising drug vehicle for cancer chemotherapy.
Polymeric micelle-based nanocarriers always encounter premature drug
leakage in sample storage or during blood circulation and poor accumulation
of drug-loaded micelles in tumor cells. Shuai et al.
14
described a novel
multifunctional CSC micelle for tumor-targeted intracellular drug release and
fluorescent imaging (Figure 9.9) to solve these problems. A triblock copolymer
of poly(ethylene glycol)-poly[N-(N9,N9-diisopropylaminoethyl)aspartamide]-
cholic acid [PEG-PAsp(DIP)-CA] was used to self-assemble into CSC micelles
