Biomimetic scaffolds offer great potentials in the development of bone analogs for tissue engineering. The studies presented in this paper focus specifically on the osteogenic potential of the novel PCL/CaP matrices and its degradation behavior. Biodegradable Polymer-ceramic Scaffolds were fabricated using the solid free form fabrication technology: Fused Deposition Modeling (FDM). The scaffold architecture was characterized by a honeycomb-like design and a complete interconnectivity of the pores. Human mesenchymal stem cells (MSCs) were seeded together with fibrin glue into PCL/CaP scaffolds and cultured in vitro for periods of up to eight weeks. Cellular adhesion, proliferation and osteogenic differentiation were assessed in these constructs using a range of histological and microscopic techniques. In additional experiments, degradation was assessed by measuring mass loss, diameter change, molecular weight change and by scanning electron micrographs. MSCs were able to adhere, migrate, and differentiate along the osteogenic lineage with in these scaffolds. The PCL/CaP scaffolds showed up to 27 fold increased degradation of compared to PCL scaffolds.

Osteogenic differentiation of mesenchymal progenitor cells in computer designed fibrin-polymer-ceramic scaffolds manufactured by fused deposition modeling

Biphasic electric current stimulates proliferation and induces VEGF production in osteoblasts

The objective of the present study was to prepare chitosan nanoparticles incorporating a relatively large plasmid encoding for osteogenic protein (OP)-1 and to determine the ability of these nanoparticles to transfect adult canine articular chondrocytes in vitro. The positive charge of chitosan acted to condense the relatively large negatively-charged OP-1 plasmid such that it could be incorporated into nanoparticles. Incorporation of the plasmid into the chitosan nanoparticles did not affect the structural integrity of the plasmid as demonstrated by gel electrophoresis. The morphology and size of the nanoparticles were found to vary with the chitosan:plasmid weight ratio. Nanoparticles formulated with a chitosan:plasmid ratio of 10:1 were of uniformly small size (less than 250 nm) and spherical shape. These nanoparticles had a positive charge of about 20 mV. FITC-labeled chitosan nanoparticles were found in virtually all of the cells after 24 h of incubation with the nanoparticles, and confocal microscopy revealed FITC-related fluorescence in the nucleus of the chondrocytes. Although transfection of the chondrocytes was demonstrated by the fluorescence of cells treated with chitosan nanoparticles containing the plasmid for the enhanced green fluorescence protein, cells transfected with nanoparticles incorporating the larger OP-1 plasmid did not show OP-1 expression measured by ELISA for up to 2 weeks in culture. These results indicate that although a large plasmid can be successfully incorporated within chitosan nanoparticles, the size of the plasmid incorporated within the nanoparticles may still significantly affect gene transfer to cells.

Plasmid size influences chitosan nanoparticle mediated gene transfer to chondrocytes.

Sequential treatment of ovariectomized mice with bFGF and risedronate restored trabecular bone microarchitecture and mineralization.

Electrical stimulation of titanium to promote stem cell orientation, elongation and osteogenesis.

Objective: To elucidate the effects of exogenous basic fibroblast growth factor ( bFGF ) on biological characteristics of rat osteoblasts cultured in vitro.
Methods: The osteoblasts isolated from a Sprague-Dawley rat and cultured in vitro were treated with different concentrations of bFGF (5-50 ng/ml) respectively. At 24 hours after treatment, the proliferating cell nuclear antigen was measured with immunocytochemistry, alkaline phosphatase ( ALP) activity was determined and the expression of transforming growth factor beta 1 (TGF-β1) was detected to observe the effects of bFGF on growth and differentiation of osteoblasts. Results: bFGF ( 5-50 ng/ml ) could obviously promote the growth of osteoblasts. The intracellular expression of TGF-β, mRNA increased significantly, but the intracellular ALP content decreased.
Conclusions: bFGF can obviously stimulate the proliferation of osteoblasts and promote the synthesis of TGF-β1, but cannot promote the differentiation of osteoblasts.

Jing-yuan Du

Papers

Effects of basic fibroblast growth factor on biological characteristics of osteoblasts.

Bioactivity of bioresorbable osteosynthetic devices made of hydroxyapatite/poly-DL-lactide composites: an experimental study.

Effects of TGF beta1 autocrine blockage on osteosarcoma cells.

Expression of rhBMP-7 gene in transduced bone marrow derived stromal cells.