Experimental Study on the Construction of Tissue Engineered Bone by Bone Marrow Mesenchymal Stem Cells Induced by MiR-29b Composite Bionic Scaffold

MiR-29b promotes osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Our study aims to evaluate MiR-29b's role in composite bionic scaffold-induced BMSCs in the construction of tissue engineered bone. Rat BMSCs were isolated and transfected with NC (negative control) and MiR-29b plasmid. Cell proliferation was assessed by MTT assay and the expression of osteogenic genes Runx2 and OC was analyzed by Real time PCR. Healthy male SD rats were divided into fracture group; negative control group; and MiR-29b group followed by analysis of the changes of bone mineral density, ALP activity, and expression of MiR-29b, type I collagen and Runx2 by Real time PCR. Up-regulation of MiR-29b significantly promoted BMSCs cell proliferation, inhibited Caspase 3 activity, and promoted Runx2 and OC expression compared to NC group (P < 0 05). NC group showed significantly increased bone density, ALP activity and the expression of type I collagen and Runx2 compared with control group (P < 0 05). Transfection of BMSCs induced by MiR-29b combined with biomimetic scaffold significantly promoted the expression of MiR-29b in fractured rats, increased bone mineral density and ALP activity, as well as upregulated type I collagen and Runx2, compared to NC group (P < 0 05). Up-regulation of MiR-29b promotes cell proliferation and osteogenic differentiation of BMSCs. Implantation of BMSCs induced by MiR-29b composite bionic scaffold can promote osteogenic differentiation and promote bone healing in bone defects.

Experimental Study on Construction of Tissue Engineered Bone by Autologous Oxygen Release Nano-Bionic Scaffold Combined with Bone Morphogenetic Protein-2 Induced Bone Marrow Mesenchymal Stem Cells

Bone marrow mesenchymal stem cells (BMSCs) are used for bone tissue engineering. BMP-2 and autologous oxygen-releasing nano-bionic scaffolds promote bone differentiation of BMSCs. Our study intends to evaluate the role of autologous oxygen-releasing nano-bionic scaffolds combined with BMP-2-induced BMSCs in the construction of tissue engineered bone. Rat BMSCs were isolated and transfected with NC (negative control group) and BMP-2 (BMP-2 plasmid group), respectively. Healthy male SD rats were randomly and equally divided into fracture group, negative control group and the BMP-2 group which was implanted with autologous oxygen-releasing nano-bionic scaffolds to synthesize BMSCs and transfected with BMP-2 plasmids respectively followed by analysis of osteophytes growth, ALP activity, expression of BMP-2, type II collagen, Runx2 and OC by real time PCR, TGF-β1 secretion by ELISA and BMP-2 protein expression by western blot. BMSCs induced by autologous oxygen release nano-bionic scaffold combined with BMP-2 can significantly promote the increase of bone mineral density, increase the expression of Runx2 and OC, promote ALP activity, upregulate type II collagen, BMP-2 mRNA and protein, and TGF-β1 secretion compared to fracture group (P < 0.05). The BMSCs induced by autologous oxygen-releasing nanobionic scaffolds transfected with BMP-2 had a more significant effect on bone repair. Autologous oxygen-releasing nano-bionic scaffolds combined with BMP-2-induced BMSCs can promote bone healing by regulating BMP-2 and increasing osteogenesis at the bone defect.

Finite Element Analysis of the Bionic Tissue Engineering Scaffold for the Defect Cranium

The relationship between the porosity and the mechanical property was still a bottle-neck in bone tissue engineering scaffold. Porosity increasing may reduce the scaffold strength. In order to solve the contradiction, the idea of enhancing the mechanical properties by controlling the scaffold porosity was proposed in this paper. Using reverse engineering technology, 5 different porosity cranium scaffolds were first established. Their FE models were built through FE surface preprocessing and volume fitted meshing. According to results of static analysis, the displacements and stresses of the 5 porosity scaffolds were compared and discussed and it indicated that the 36% porosity bionic scaffold have good porous level and mechanical properties.

Freeze Drying Technology Forming Drug Release Bionic Scaffolds with Gradient Structure

A kind of drug release bionic scaffold with gradient structure was designed to release drugs. The scaffold mould had been designed with CAD software and fabricated with rapid prototype. The bionic beta-tricalcium phosphate (β-TCP) scaffold was fabricated with freeze drying. It was composed of two coaxial cylindrical porous scaffolds. The internal loose scaffold was embedded in the outer dense layer. The two different density layers of the scaffold could be used to adjust the drug releasing rate through regulating the slurry concentration. The scaffold was distributed with pores ranged from 30μm to 100μm. The research indicated that the scaffold with gradient structure could be loaded with two kinds of drugs which were released at different rate. The scaffolds were fit as the substitute materials for bone repairing.