Biomedical Engineering Reference
In-Depth Information
A
Self-assembly
PBS, pH 7.4
E
ndocyto
sis
DOX-loaded
mPEG-S
2
-
PZLL
micelle
Intracellular DOX release with
reductive cleavage of disulfide linkage
a
B
C
a
c
b
c
d
90
b
100
60
50
30
0
0
10
-1
10
0
10
1
0
20
40
60
Time (h)
Flurescence Intensity
Figure 15.2
(A) Schematic illustration of DOX loading and targeting intracellular release.
(B) DOX release from (a and b) h e DOX-loaded mPEG
113
-
S
2
-PZLL
18
micelles and (c and
d) mPEG
113
-S
2
-PZLL
35
micelles at pH 7.4 (a and c) without GSH and with (b and d) 10.0
mM GSH in PBS at 37 °C. (C) Flow cytometric proi les of HeLa cells incubated with the
DOX-loaded mPEG
113
-
S
2
-PZLL
18
micelles for 2 h: (a) cells without pretreatment; (b) cells
pretreated with 0.5 mM BSO; (c) cells pretreated with 10.0 mM GSH-OEt. Reproduced
with permission from [2].
15.2.2 Polypeptide Vesicles
Polymeric vesicles (also known as polymersomes) are one kind of
nanoscale or microscale hollow reservoir-like spheres composed of hydro-
phobic interlayer, hydrophilic external and internal shells [55-59]. In con-
trast to the polymeric micelles, polymeric vesicles can both encapsulate
hydrophilic therapeutic molecules in their aqueous cavities and integrate
hydrophobic bioactive agents within the hydrophobic membrane [57,
58]. Polymeric vesicles have great potential as versatile carriers ascribed
to their colloidal stability, tunable membrane thickness and permeability,
