Direct ink writing of highly porous and strong glass scaffolds for load-bearing bone defects repair and regeneration

Abstract

The quest for synthetic materials to repair load-bearing bone lost because of trauma, cancer, or congenital bone defects requires development of porous and high-performance scaffolds with exceptional mechanical strength. However, the low mechanical strength of porous bioactive ceramic and glass scaffolds, compared with that of human cortical bone, has limited their use for these applications. In the present work, bioactive 6P53B glass scaffolds with superior mechanical strength were fabricated using a direct ink writing technique. The rheological properties of Pluronic® F-127 (referred to hereafter simply as F-127) hydrogel-based inkswere optimized for the printing of features as fine as 30 μm and of the three-dimensional scaffolds. The mechanical strength and in vitro degradation of the scaffolds were assessed in a simulated body fluid (SBF). The sintered glass scaffolds show a compressive strength (136 ± 22 MPa) comparable to that of human cortical bone (100-150 MPa), while the porosity (60%) is in the range of that of trabecular bone (50-90%).The strength is ~100 times that of polymer scaffolds and 4–5 times that of ceramic and glass scaffolds with comparable porosities. Despite the strength decrease resulting from weight loss during immersion in an SBF, the value (77 MPa) is still far above that of trabecular bone after three weeks. The ability to create both porous and strong structures opens a new avenue for fabricating scaffolds for load-bearing bone defect repair and regeneration.

Additive Manufacturing of Ceramic‐Based Materials

“…[152] Another approach is to embed particles into a thermoreversible hydrogel. [147,[153][154][155] This route is also applied in socalled bioplotting, which works similar to FDC whereas the liquid phase of the feedstock is not frozen upon deposition but passes a gel point and thus solidifies in a cooled bath. For UV/ heat-curable inks, the powder is embedded and dispersed into a monomer/oligomer liquid doped with UV-sensitive polymerization initiators.…”

Tailoring Mechanical Properties of Sol–Gel Hybrids for Bone Regeneration through Polymer Structure

“…Porous bioactive glass scaffolds can be fabricated with inter-connected pores and compressive strengths that match porous bone 5,6,7 , but they are too brittle for sites that are subjected to cyclic loading 5,8,9 . Inorganic-organic hybrids are of great interest because their molecular level interaction between the two components can provide synergistic properties while acting as a single phase material 10,11,12,13 .…”

Osseous differentiation on freeze casted 10CeTZP-Al2O3 structures

“…No noticeable differences or trend are appreciated among the average closed porosity values (~6% ± 1% in every case), which indicates that they do not depend on solid concentrations or cooling rates. Pore size is critical to determine the suitability of a specific structure for bone scaffold applications, since osteoblast-like cells, which need to enter and colonize the scaffold, measure approximately 20-30 µm in diameter [32]. During this study, both the small and the large diameters of the elliptical pores were considered.…”