Various strategies have been explored to overcome critically sized bone defects via bone tissue engineering approaches that incorporate biomimetic scaffolds. Biomimetic scaffolds may provide a novel platform for phenotypically stable tissue formation and stem cell differentiation. In recent years, osteoinductive and inorganic biomimetic scaffold materials have been optimized to offer an osteo-friendly microenvironment for the osteogenic commitment of stem cells. Furthermore, scaffold structures with a microarchitecture design similar to native bone tissue are necessary for successful bone tissue regeneration. For this reason, various methods for fabricating 3D porous structures have been developed. Innovative techniques, such as 3D printing methods, are currently being utilized for optimal host stem cell infiltration, vascularization, nutrient transfer, and stem cell differentiation. In this progress report, biomimetic materials and fabrication approaches that are currently being utilized for biomimetic scaffold design are reviewed.
Uncontrolled bleeding can lead to
many complications that might
cause multiple organ failures and even death. Of all the hemostatic
agents used, chitosan has been reported to show better hemostatic
potential. It acts through one mechanism involved in hemostasis that
is plug formation by adhering to the injured site. Hence our focus
is to enhance the hemostatic potential of chitosan (Ch) hydrogel by
incorporating nano whitlockite (nWH: Ca18Mg2(HPO4)2(PO4)12) that
would release Ca2+, Mg2+, and PO4
3– ions that would simultaneously initiate the
coagulation cascade. Ch-nWH composite hydrogel can act simultaneously
on different mechanisms involved in hemostasis and bring about rapid
bleeding control. The nWH particles were synthesized using precipitation
technique and were characterized. Particle size of nWH was found to
be 75 ± 5 nm. Composite hydrogel was characterized using FTIR
and XRD to confirm the presence of different constituents of the hydrogel.
Rheological studies showed the shear-thinning property and increased
elastic modulus of the composite hydrogel compared to Ch hydrogel.
2%Ch-4%nWH hydrogel was observed to be cytocompatible with Human Umbilical
Vein Endothelial Cells (HUVEC). In the in vitro blood clotting analysis
using citrated human whole blood, 2%Ch-4%nWH hydrogel showed rapid
blood clot formation compared to control 2%Ch hydrogel. Further in
vivo experiments performed on liver and femoral artery injuries created
on Sprague–Dawley (S.D) rat model reveals that 2%Ch-4%nWH hydrogel
promoted rapid bleeding control and less volume of blood loss compared
to Ch hydrogel. These in vitro and in vivo results showed that incorporation
of nWH has enhanced the hemostatic potential of Ch hydrogel. Therefore,
the synthesized 2%Ch-4%nWH hydrogel may be a promising system that
could bring about rapid hemostasis during life threatening bleeding.
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