6 research outputs found
Heparin Functionalized Injectable Cryogel with Rapid Shape-Recovery Property for Neovascularization
Cryogel based scaffolds
have high porosity with interconnected
macropores that may provide cell compatible microenvironment. In addition,
cryogel based scaffolds can be utilized in minimally invasive surgery
due to its sponge-like properties, including rapid shape recovery
and injectability. Herein, we developed an injectable cryogel by conjugating
heparin to gelatin as a carrier for vascular endothelial growth factor
(VEGF) and fibroblasts in hindlimb ischemic disease. Our gelatin/heparin
cryogel showed gelatin concentration-dependent mechanical properties,
swelling ratios, interconnected porosities, and elasticities. In addition,
controlled release of VEGF led to effective angiogenic responses both <i>in vitro</i> and <i>in vivo</i>. Furthermore, its
sponge-like properties enabled cryogels to be applied as an injectable
carrier system for <i>in vivo</i> cells and growth factor
delivery. Our heparin functionalized injectable cryogel facilitated
the angiogenic potential by facilitating neovascularization in a hindlimb
ischemia model
Enhanced Osteogenic Commitment of Human Mesenchymal Stem Cells on Polyethylene Glycol-Based Cryogel with Graphene Oxide Substrate
Graphene
oxide (GO) is considered a comparatively recent biomaterial
with enormous potential because of its nontoxicity, high dispersity,
and enhanced interaction with biomolecules. These characteristics
of GO can promote the interactions between the substrates and cell
surfaces. In this study, we incorporated GO in a cryogel-based scaffold
system to observe their influence on the osteogenic responses of human
tonsil-derived mesenchymal stem cells (hTMSCs). Compared to polyethylene
glycol (PEG)-based cryogel scaffold, GO-embedded PEG-based (PEGDA-GO)
cryogels not only showed improved cell attachment and focal adhesion
kinase (FAK) signaling activation but also enhanced cell viability.
Taken together, we demonstrated that PEGDA-GO cryogels can stimulate
osteogenic differentiation under an osteoinductive condition and enhance
osteogenic phenotypes compared to the control group. In summary, we
demonstrate that GO embedded in cryogels system is an effective biofunctionalizing
scaffold to control osteogenic commitment of stem cells
Lineage Specific Differentiation of Magnetic Nanoparticle-Based Size Controlled Human Embryoid Body
Human embryonic stem cells (hESCs)
possess unique properties in
terms of self-renewal and differentiation, which make them particularly
well-suited for use in tissue engineering and regenerative medicine.
The differentiation of hESCs in the form of human embryoid bodies
(hEBs) recapitulates early embryonic development, and hEBs may provide
useful insight into the embryological development of humans. Herein,
cell-penetrating magnetic nanoparticles (MNPs) were utilized to form
hEBs with defined sizes and the differentiation patterns were analyzed.
Through intracellular delivery of MNPs into the hESCs, suspended and
magnetized hESCs efficiently clustered in to hEBs driven by magnetic
pin-based external magnetic forces. The hEB size was controlled by
varying the suspended cell numbers that were applied in the magnetic
pin system. After 3 days of differentiation in a suspended condition,
ectodermal differentiation was observed to have been enhanced in the
small hEBs (150 Ī¼m in diameter) while endodermal and mesodermal
differentiation were enhanced in large hEBs (600 Ī¼m in diameter).
This indicates that the size of the hEBs plays an important role in
the early lineage commitment of hESCs, and MNP-based control of the
hEB size would be a novel, useful methodology for lineage-specific
hESC differentiation
Magnetic Nanoparticle-Embedded Hydrogel Sheet with a Groove Pattern for Wound Healing Application
Endothelial progenitor cells (EPCs)
can induce a pro-angiogenic
response during tissue repair. Recently, EPC transplantations have
been widely investigated in wound healing applications. To maximize
the healing efficacy by EPCs, a unique scaffold design that allows
cell retention and function would be desirable for in situ delivery. Herein, we fabricated an alginate/poly-l-ornithine/gelatin
(alginate-PLO-gelatin) hydrogel sheet with a groove pattern for use
as a cell delivery platform. In addition, we demonstrate the topographical
modification of the hydrogel sheet surface with a groove pattern to
modulate cell proliferation, alignment, and elongation. We report
that the patterned substrate prompted morphological changes of endothelial
cells, increased cellācell interaction, and resulted in the
active secretion of growth factors such as PDGF-BB. Additionally,
we incorporated magnetic nanoparticles (MNPs) into the patterned hydrogel
sheet for the magnetic field-induced transfer of cell-seeded hydrogel
sheets. As a result, enhanced wound healing was observed via efficient
transplantation of the EPCs with an MNP-embedded patterned hydrogel
sheet (MPS). Finally, enhanced vascularization and dermal wound repair
were observed with EPC seeded MPS
Chondroitin Sulfate-Based Biomineralizing Surface Hydrogels for Bone Tissue Engineering
Chondroitin
sulfate (CS) is the major component of glycosaminoglycan
in connective tissue. In this study, we fabricated methacrylated PEGDA/CS-based
hydrogels with varying CS concentration (0, 1, 5, and 10%) and investigated
them as biomineralizing three-dimensional scaffolds for charged ion
binding and depositions. Due to its negative charge from the sulfate
group, CS exhibited an osteogenically favorable microenvironment by
binding charged ions such as calcium and phosphate. Particularly,
ion binding and distribution within negatively charged hydrogel was
dependent on CS concentration. Furthermore, CS dependent biomineralizing
microenvironment induced osteogenic differentiation of human tonsil-derived
mesenchymal stem cells in vitro. Finally, when we transplanted PEGDA/CS-based
hydrogel into a critical sized cranial defect model for 8 weeks, 10%
CS hydrogel induced effective bone formation with highest bone mineral
density. This PEGDA/CS-based biomineralizing hydrogel platform can
be utilized for in situ bone formation in addition to being an investigational
tool for in vivo bone mineralization and resorption mechanisms
General and Facile Coating of Single Cells via Mild Reduction
Cell surface modification has been
extensively studied to enhance
the efficacy of cell therapy. Still, general accessibility and versatility
are remaining challenges to meet the increasing demand for cell-based
therapy. Herein, we present a facile and universal cell surface modification
method that involves mild reduction of disulfide bonds in cell membrane
protein to thiol groups. The reduced cells are successfully coated
with biomolecules, polymers, and nanoparticles for an assortment of
applications, including rapid cell assembly, in vivo cell monitoring,
and localized cell-based drug delivery. No adverse effect on cellular
morphology, viability, proliferation, and metabolism is observed.
Furthermore, simultaneous coating with polyethylene glycol and dexamethasone-loaded
nanoparticles facilitates enhanced cellular activities in mice, overcoming
immune rejection