| Objective:Through the study of the hydrogels encapsulating rat bone marrow mesenchymal stem cells in vitro and the induction of cell proliferation and osteogenic differentiation, oligo (poly(ethylene glycol) fumarate) hydrogel materials with appropriate molecular weights were selected. Oligo (poly(ethylene glycol) fumarate)/graphene oxide composite hydrogel was developed and related bilological evaluation of composite hydrogel encapsulated stem cells for promoting their osteogenic differentiation was carried out.Methods:Oligo (poly(ethylene glycol) fumarate) was crosslinked by a redox radical initiation system, oligo (poly(ethylene glycol) fumarate) hydrogels with four kinds of molecular weights were prepared and their gelation times, swelling and degradation properties were measured. Bone marrow mesenchymal stem cells were encapsulated in the hydrogels with four molecular weights and the experiments were divided into four groups. They were all cultured in osteogenic culture medium for 1-3 weeks and the effects of hydrogel materials on cellular morphology and osteogenic differentiation of bone marrow mesenchymal stem cells were evaluated via histological staining (Hematoxylin-Eosin staining and alizarin red staining) and immunofluorescence staining to select out the oligo (poly(ethylene glycol) fumarate) hydrogel with suitable molecular weight. Oligo (poly(ethylene glycol) fumarate)/graphene oxide composite hydrogel was prepared via a physical blending method that graphene oxide was mingled in the oligo (poly(ethylene glycol) fumarate) and its physical and chemical properties were evaluated. Bone marrow mesenchymal stem cells were then encapsulated in this hydrogel and experienced osteogenic induction culture. After 3,7, 14 and 21 days, the effects of this composite hydrogel on the morphology and osteogenic differentiation of bone marrow mesenchymal stem cells were detected by Hematoxylin-Eosin staining, Von Kossa staining, alizarin red staining and immunofluorescence staining.Results:With the increase of the molecular weight of the hydrogel, when the gelation time is shorter, the swelling degree increases significantly. And over tine, the larger the molecular weight of the hydrogel is, the faster is the degradation rate, that is to say the hydrogel degradation rate is proportional to the molecular weight. The result of toxicity test shows that oligo (poly(ethylene glycol) fumarate) hydrogel has good biocompatibility. The results of histological and immunofluorescence staining of cells encapsulated in composite hydrogel scaffold suggested that, afher induction, the number of mineralized nodules formed in the hydrogels with the molecular weights (3K and 10K) that possess appropriate swelling and degradation properties was significantly higher than that of other two molecular weights, which shows that it is beneficial for cell proliferation and differentiation. Though the histological and immunofluorescence staining of cell encapsulated oligo (poly(ethylene glycol) fumarate)/graphene oxide composite hydrogel at different time points (3,7,14 and 21 days), it is found that cells in the hydrogels grows and proliferates well. And with the extension of osteogenic induction, mineralized nodules and osteogenic gene expression gradually increases. Moreover, oligo (poly(ethylene glycol) fumarate)/graphene oxide composite hydrogel can significantly improve the osteogenenic differentiation of bone marrow mesenchymal stem cells compared to the pure oligo (poly (ethylene glycol) fumarate) hydrogel.Conclusion:Research shows that oligo (poly(ethylene glycol) fumarate) hydrogel has good biocompatibility for bone marrow mesenchymal stem cells and the hydrogels with molecular weights of 3K and 10K have a benign regulation for osteogenenic differentiation in a certain extent. Oligo (poly(ethylene glycol) fumarate)/graphene oxide composite hydrogel can promote cells proliferation and induce their osteogenenic differentiation and it is a good scaffold for bone tissue engineering. |
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