Biomedical Engineering Reference
In-Depth Information
efficiency as well as lower cytotoxicity compared to 25 kDa PEI in various
tumor cell lines and different mouse models. Xiao and co-workers synthesized
(dextran-hexamethylene diisocyanate)-g-polyethylenimine [(Dex-HMDI)-g-
PEI] as a siRNA vector (Scheme 4.2B).
17
This dextran-linked compound
showed reduced cytotoxicity and significant knockdown ability compared to
25 kDa PEI.
Luo et al. developed a ''hydroxylation camouflage'' strategy to pro-
mote serum-tolerant capability of polycation-based gene delivery systems
(Scheme 4.2C).
18
In this design, a 25 kDa PEI surface was coated with
abundant hydroxyl groups via a catalyst-free ring-opening aminolysis reaction
with 5-ethyl-5-(hydroxymethyl)-1,3-dioxan-2-one (EHDO). The results indi-
cated that the serum-tolerant capability largely depended on the surface
composition and substitution degree. The hydroxyl-enriched ''skin'' would
render PEI-g-EHDO with remarkably improved biocompatibility and stronger
resistance against the serum-associated detrimental effects such as protein
d
n
4
y
3
n
g
|
3
Scheme
4.2
Synthesis
of
(A) b-CD-modified
PEI,
(B)
dextran-modified
PEI
copolymers, and (C) hydroxyl-enriched PEI.
