Highly degradable porous melt-derived bioactive glass foam scaffolds for bone regeneration

A challenge in using bioactive melt-derived glass in bone regeneration is to produce scaffolds with interconnected pores while maintaining the amorphous nature of the glass and its associated bioactivity. Here we introduce a method for creating porous melt-derived bioactive glass foam scaffolds with low silica content and report in vitro and preliminary in vivo data. The gel-cast foaming process was adapted, employing temperature controlled gelation of gelatin, rather than the in situ acrylic polymerisation used previously. To form a 3D construct from melt derived glasses, particles must be fused via thermal processing, termed sintering. The original Bioglass® 45S5 composition crystallises upon sintering, altering its bioactivity, due to the temperature difference between the glass transition temperature and the crystallisation onset being small. Here, we optimised and compared scaffolds from three glass compositions, ICIE16, PSrBG and 13–93, which were selected due to their widened sintering windows. Amorphous scaffolds with modal pore interconnect diameters between 100–150 µm and porosities of 75% had compressive strengths of 3.4 ± 0.3 MPa, 8.4 ± 0.8 MPa and 15.3 ± 1.8 MPa, for ICIE16, PSrBG and 13–93 respectively. These porosities and compressive strength values are within the range of cancellous bone, and greater than previously reported foamed scaffolds. Dental pulp stem cells attached to the scaffold surfaces during in vitro culture and were viable. In vivo, the scaffolds were found to regenerate bone in a rabbit model according to X-ray micro tomography imaging

Tailoring of bone scaffold properties using silicate/phosphate glass mixtures

Different ratios of a resorbable phosphate glass (ICEL) and a bioactive silicate glass (CEL2) were co-sintered to obtain 3D porous scaffolds by gel-cast foaming method. The scaffold morphology, crystalline phases and compressive strength were studied. All the scaffolds showed a 3D structure with highly interconnected pores. The ICEL/CEL2 co-sintering resulted in a lower shrinkage leading to higher scaffold porosity (more than 70 vol%) compared to pure ICEL and CEL2 (about 65 vol%). Tuning ICEL/CEL2 ratio allowed the modulation of the scaffold resorption rate, with weight loss ranging from 20% to 75% after soaking for 3 months in simulated body fluid. Scaffolds containing higher amount of CEL2 silicate glass, resulted in a very high bioactivity.In vitrobiological test showed no toxic effect of the scaffolds on human osteoblast-like cells.</jats:p