Resorbable Glass–Ceramic Phosphate-based Scaffolds for Bone Tissue Engineering: Synthesis, Properties, andIn vitroEffects on Human Marrow Stromal Cells

Abstract

Highly porous bioresorbable glass-ceramic scaffolds were prepared via sponge replication method by using an open-cell polyurethane foam as a template and phosphate-based glass powders. The glass, belonging to the P2O5-SiO2-CaO-MgO-Na2O-K2O system, was synthesized by a melting-quenching route, ground, and sieved to obtain powders with a grain size of less than 30 μm. A slurry containing glass powders, polyvinyl alcohol, and water was prepared to coat the polymeric template. The removal of the polymer and the sintering of the glass powders were performed by a thermal treatment, in order to obtain an inorganic replica of the template structure. The structure and properties of the scaffold were investigated from structural, morphological, and mechanical viewpoints by means of X-ray diffraction, scanning electron microscopy, density measurements, image analysis, and compressive tests. The scaffolds exhibited a trabecular architecture that closely mimics the structure of a natural spongy bone. The solubility of the porous structures was assessed by soaking the samples in acellular simulated body fluid (SBF) and Tris-HCl for different time frames and then by assessing the scaffold weight loss. As far as the test in SBF is concerned, the nucleation of hydroxyapatite on the scaffold trabeculae demonstrates the bioactivity of the material. Biological tests were carried out using human bone marrow stromal cells to test the osteoconductivity of the material. The cells adhered to the scaffold struts and were metabolically active; it was found that cell differentiation over proliferation occurred. Therefore, the produced scaffolds, being biocompatible, bioactive, resorbable, and structurally similar to a spongy bone, can be proposed as interesting candidates for bone grafting.

Trabecular coating on curved alumina substrates using a novel bioactive and strong glass-ceramic

“…The high compressive strength suggests the suitability of S50P3 scaffolds as trabecular coatings for load-bearing prosthetic applications. The fracture energy of S50P3 scaffolds (around 6.5×10 −4 J mm −3 ) is comparable to that assessed for SCNA scaffolds with the same porosity [33], but is significantly higher (more than one order of magnitude) than that of HA [34] and phosphate glass scaffolds [35] reported in the literature. The good in vitro bioactivity of S50P3 scaffolds is demonstrated by the formation of an apatite-like layer on the pore struts (Fig.…”

Quantifying the micro-architectural similarity of bioceramic scaffolds to bone

“…The requirements that an ideal scaffold for bone tissue engineering should fulfill include high porosity (above 50 vol% as in trabecular bone), presence of macropores with size exceeding 100 µm to permit cell migration and scaffold colonization/vascularization, and three-dimensional (3D) interconnectivity of the pore network to allow adequate perfusion of nutrient-rich medium or biological fluids [3][4][5]. When mechanical support is required till healing, scaffold mechanical properties should match those of the specific bone tissue to replace and material degradation rate should also match the kinetics of bone ingrowth [6,7].…”

Electrophoretic deposition of mesoporous bioactive glass on glass–ceramic foam scaffolds for bone tissue engineering

“…The scaffolds compressive strength is above the standard reference range (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) ) considered for human trabecular bone as well as most of foam-like scaffolds with the same porosity reported in the literature [11]; therefore, the produced samples can be proposed even for load-bearing applications like in joint prostheses [13,14]. The fracture energy is from one to two orders of magnitude higher than that reported for other glass-ceramic scaffolds produced by the same method and having analogous macroporous architecture [44,45]; in this regard, a key role is played by the formulation of the starting glass (SCNA) in affecting the sintering behaviour of glass particles and the densification of the scaffold struts.…”