Biomedical Engineering Reference
In-Depth Information
Doxorubicin release-profile from the hexamethylene diisocyanate-Pluronic
®
F127/
HA composite hydrogel was almost zero-order release during 28 days [
73
]. This
system also showed antitumor efficacy and therapeutic effects in animal study.
HA and fibrin hydrogels with plasmid DNA (pDNA)/PEI polyplexes loaded
through the caged nanoparticle encapsulation were able to deliver genes in vivo
without aggregation [
112
]. Oxidized alginate hydrogels loaded with DNA/PEI
nDNA were shown to achieve sustained release in vitro and achieve enhanced
revascularization in vivo [
113
]. Alginate hydrogels conjugated with various RGD
densities for siRNA-mediated knockdown of eGFP demonstrated that increasing
RGD density resulted in significantly higher knockdown of the targeted protein
[
114
]. Nanostructured micelles-containing PEG based hydrogels that encapsulated
cationic bolaamphiphile/DNA complexes and human mesenchymal stem cells
(hMSCs) showed higher gene expression efficiency in hMSCs than the PEI/DNA
complexes [
24
]. A CD-based supramolecular hydrogel system with supramolec-
ularly anchored active cationic copolymer/pDNA polyplexes was able to sustain
release of pDNA up to 6 days [
115
]. Hydrogel stiffness can also be used to modu-
late migration and gene delivery rates; stiffer gels result in slower release rates of
encapsulated polyplexes and decreased cell populations, spreading, and transfec-
tion [
116
].
Hydrogels have been used for wound healing as moist wound dressing mate-
rials. Hydrogels not only keep the wound moist, but also help proliferation of
fibroblasts to recover defects. Rutin-conjugated chitosan-PEG-tyramine hydro-
gels showed enhanced dermal wound healing efficacy and tissue-adhesive prop-
erty [
117
]. Fibroblasts encapsulated PEG-L-PA hydrogels significantly improved
in vivo wound healing rate than controls of PBS treated or cell-free PEG-L-PA
hydrogel treated group [
118
]. Treatment of dextran based hydrogels on burn
wound promoted neovascularization and skin regeneration [
119
]. The PECE
hydrogel was treated to the full-thickness skin incision wounds and accelerated
wound healing compared to untreated controls [
111
]. In situ forming hydrogels
also can be used for prevention of postoperarive adhesion [
120
]. When biodegrad-
able and thermoreversible PCLA-PEG-PCLA hydrogel treated onto the peritoneal
wall defect, postoperative adhesion significantly reduced.
In situ hydrogel systems have been used for tissue engineering. For tissue engi-
neering, usually patient-derived healthy cells are expanded in vitro, mixed with
polymer solutions and bioactive molecules, and then inject into a defect area to
form a hydrogel in situ. Fibronectin- and NT-3-functionalized silk hydrogels that
triggered axonal bundling [
121
] and self-assembling peptide hydrogel of RADA
16
-
IKVAV (AcN-RADARADARADARADAIKVAV-CONH
2
) that accelerated cen-
tral nervous system brain tissue regeneration [
122
] were developed as neural
tissue engineering systems. Thermosensitive PNIPAAm-O-phosphoethanolamine
grafted poly(acrylic acid)-PNIPAAm hydrogel showed potential as an osteogenic
matrix [
123
]. Mixture of chondroitin sulfate succinimidyl succinate (CS-NHS) and
freeze-thawed bone marrow aspirate formed hydrogels and showed potentials as
a meniscus repair system [
124
] or an articular cartilage regenerative matrix when
rhBMP-2 localized within the hydrogel [
125
]. Thermoresponsive and various
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