Biomedical Engineering Reference
In-Depth Information
activity than the DOX-loaded nanogels at er incubation for 72 h, while
free CAD and DAD showed lower cytotoxicities toward both HeLa and
HepG2 cells in contrast to free DOX for the duration of test. Furthermore,
in Chen's group, the diselenide bond was employed to crosslink methoxy
poly(ethylene glycol)-
block
-poly(L-glutamic acid-
co
-γ-2-chloroethyl-L-
glutamate) micelle, yielding a pH and dual-redox responsive nanogel [23].
DOX was loaded into nanogel through the dif usion approach, and a faster
release was observed in the presence of GSH (only 0.5 mmol).
Deng, Zhong and coworkers have exploited the pH and reduction
dual-responsive nanogels through crosslinking lipoic acid (LA) and
cis
-
1,2-cyclohexanedicarboxylic acid (CCA) decorated PEG-
b
-PLL (PEG-
b
-
P(LL-
g
-LA/CCA)) micelles in the presence of a catalytic amount of DTT
in PBS at pH 7.4 [79]. DOX was loaded into nanogels through nanopre-
cipitation and subsequent core crosslinking. h e release of DOX from
drug-loaded nanogels was improved at endosomal pH (i.e., 5.0) or under
a reductive condition containing 10.0 mM GSH, possibly triggered by the
cleavage of acid-labile amide bond of CCA or disuli de bond, respectively.
h e pH and reduction dual-responsive nanogels were biocompatible,
whereas the DOX-loaded nanogels caused pronounced cytotoxic ef ects
toward HeLa and HepG2 cells.
15.2.4
Other Smart Polypeptide Nanovehicles
In addition to the abovementioned mainstream systems, there are some
other interesting smart polypeptide nanovehicles with various morphol-
ogies (e.g., nanocapsules) and stimuli-responsivenesses (e.g., thermo-
responsiveness) for intelligent antitumor drug delivery. For example,
Huang and coworkers have prepared polypeptide nanocapsule through
layer-by-layer self-assembly of PLGA and platinum(IV) conjugated PLL
(PLL-
g
-Pt(IV)) on colloidal silica templates, followed by removal of the
templates [80]. h e release rate and amount of platinum from nanocap-
sule were increased in acidic and/or reductive conditions. In addition, the
PLGA/PLL-
g
-Pt(IV) nanocapsule displayed enhanced antitumor ei cacy
against CT-26 cells (a murine colon carcinoma cell line) in comparison
with free CDDP. Moreover, a series of thermo-responsive micelles based
on “hairy-rod” polypeptides, which were ei ciently synthesized by grat -
ing of azide-terminated copolymers of 2-(2-methoxyethoxy)ethyl meth-
acrylate (MEO
2
MA) or 2-(2-(2-methoxyethoxy)ethoxy)ethyl methacrylate
(MEO
3
MA) (
i.e.
,
N
3
-PMEO
i
MA) onto PPLG through a “click” reaction,
were exploited by Chen's group [39]. DOX was ei ciently loaded into
