Preparation and in vitro evaluation of bioactive glass (13-93) scaffolds with oriented microstructures for repair and regeneration of load-bearing bones.

Bioactive glass (13-93) scaffolds with oriented microstructures, referred to as 'columnar' and 'lamellar', were prepared by unidirectional freezing of suspensions, and evaluated in vitro for potential use in the repair and regeneration of load-bearing bones in vivo. Both groups of scaffolds showed an 'elastic-plastic' mechanical response in compression, large strain for failure (>20%), and strain rate sensitivity, but the columnar scaffolds had the additional advantages of higher strength and larger pore width. At the equivalent porosity (55-60%) and deformation rate (0.5 mm/min), the columnar scaffolds had a compressive strength of 25 +/- 3 MPa, elastic modulus of 1.2 GPa, and pore width of 90-110 microm, compared to values of 10 +/- 2 MPa, 0.4 GPa, and 20-30 microm, respectively, for the lamellar scaffolds. Cellular response to the scaffolds was evaluated using murine MLO-A5 cells, an osteogenic cell line. While the cellular response to both groups of scaffolds was better than control wells, the columnar scaffolds with the larger pore width provided the most favorable substrate for cell proliferation and function. These results indicate that 13-93 bioactive glass scaffolds with the columnar microstructure could be used for the repair and regeneration of load-bearing bones in vivo.