2 research outputs found
Rh(II)/Brønsted Acid Cocatalyzed Intramolecular Trapping of Ammonium Ylides with Enones: Diastereoselective Synthesis of 2,2,3-Trisubstituted Indolines
Highly diastereoselective intramolecular
trapping of ammonium ylides
with enones has been developed through a RhÂ(II)/Brønsted acid
cocatalytic strategy. This process allows rapid and efficient construction
of <i>N</i>-unprotected polyfunctional 2,2,3-trisubstituted
indolines in moderate to good yields with excellent diastereoselectivity
Thermoresponsive Citrate-Based Graphene Oxide Scaffold Enhances Bone Regeneration from BMP9-Stimulated Adipose-Derived Mesenchymal Stem Cells
Effective
bone tissue engineering is important to overcome the
unmet clinical challenges as more than 1.6 million bone grafts are
done annually in the United States. Successful bone tissue engineering
needs minimally three critical constituents: osteoprogenitor cells,
osteogenic factors, and osteoinductive/osteoconductive scaffolds.
Osteogenic progenitors are derived from multipotent mesenchymal stem
cells (MSCs), which can be prepared from numerous tissue sources,
including adipose tissue. We previously showed that BMP9 is the most
osteogenic BMP and induces robust bone formation of immortalized mouse
adipose-derived MSCs entrapped in a citrate-based thermoresponsive
hydrogel referred to as PPCNg. As graphene and its derivatives emerge
as promising biomaterials, here we develop a novel thermosensitive
and injectable hybrid material by combining graphene oxide (GO) with
PPCNg (designated as GO-P) and characterize its ability to promote
bone formation. We demonstrate that the thermoresponsive behavior
of the hybrid material is maintained while effectively supporting
MSC survival and proliferation. Furthermore, GO-P induces early bone-forming
marker alkaline phosphatase (ALP) and potentiates BMP9-induced expression
of osteogenic regulators and bone markers as well as angiogenic factor
VEGF in MSCs. In vivo studies show BMP9-transduced MSCs entrapped
in the GO-P scaffold form well-mineralized and highly vascularized
trabecular bone. Thus, these results indicate that GO-P hybrid material
may function as a new biocompatible, injectable scaffold with osteoinductive
and osteoconductive activities for bone regeneration