In vivo response of porous hydroxyapatite and β‐tricalcium phosphate prepared by aqueous solution combustion method and comparison with bioglass scaffolds

Abstract

Pure hydroxyapatite (HAp) and a biphasic calcium phosphate [containing 90% of beta-tri-calcium phosphate (beta-TCP) and 10% HAp] were tailored through an aqueous solution combustion synthesis. Porous struts were prepared using all the powders along with bioglass, a known bioactive material, and subsequently characterized. Sterilized struts were implanted to the lateral side of radius bone of 24 black Bengal goats of either sex, in which a blank hole was left unfilled in a group of six specimens to act as control. The bone formation response of the three implanting materials in vivo has been studied using scanning electron microscope and histological analysis in contrast with positive controls. Push-out tests were used to assess the mechanical strength at the bone-biomaterial interface. It was observed that interfacial response was strongly dependent on combinations of different physical and chemical parameters. The surface of beta-TCP exhibited similar characteristics of bone and was distinct from those of intervening apatite layer of bioglass. Lower bone ingrowth and reduced strength was observed with HAp compared to beta-TCP/bioglass-based implants. Bone formation response of the Ca-P material varied according to the composition of the implanting material, which could be tailored through this novel synthesis.

Bioactive glass and glass-ceramic scaffolds for bone tissue engineering

“…In vivo results have confirmed that BG is able to stimulate and promote neo-vascularization [52,55,[120][121][122]164,203,206,[208][209][210][211]. For example, Leu et al [211] filled calvarial defects in SpragueDawley rats with 45S5 Bioglass ® impregnated (1.2 mg) collagen sponges (volume = 0.05 cm 3 ) and unloaded, empty sponge as a control.…”

“…Bioactive silicate glasses exhibit several advantages in comparison to other bioactive ceramics, e.g., sintered hydroxyapatite, in tissue engineering applications. For example, it has been demonstrated that dissolution products from bioactive glasses up-regulate the expression of genes that control osteogenesis [7,51], which explains the higher rate of bone formation in comparison to other inorganic ceramics such as hydroxyapatite [52]. Further studies using 45S5 Bioglass ® particles have shown encouraging results regarding potential angiogenic effects of Bioglass ® , i.e., increased secretion of vascular endothelial growth factor (VEGF) and VEGF gene expression in vitro, as well as enhancement of vascularization in vivo [53][54][55][56] (see §4).…”

“…Recent developments related to bone TE try to bridge this gap and overcome this problem by architectures and components carefully designed from comprehensive levels, i.e., from the macro-, meso-, micrometer down to the nanometer scale [101], including both multifunctional bioactive glass composite structures (see §3.2) and advanced bioactive glass-ceramic scaffolds exhibiting oriented microstructures, controlled porosity and directional mechanical properties [99,[102][103][104][105], as discussed in the following paragraphs. Most studies have investigated mainly the mechanical properties, in vitro and cell biological behavior of glass-ceramic scaffolds [13][14][15]30,43,52,94,95,97,99,, as summarized in Table 1, and scaffolds with compressive strength [99,102] and elastic modulus values [99,105] in magnitudes far above that of cancellous bone and close to the lower limit of cortical bone have been realized. Fu et al [99] fabricated bioactive glass (13-93) scaffolds with oriented (i.e., columnar and lamellar) microstructures and found that at an equivalent porosity of 55-60%, the columnar scaffolds had a compressive strength of 25 ± 3 MPa, compressive modulus of 1.2 GPa, and pore width of 90-110 µm, compared to values of 10 ± 2 MPa, 0.4 GPa, and 20-30 μm, respectively, for the lamellar scaffolds.…”

“…In addition to providing excellent in vitro bioactivity [14,43,94,109,110,115], cell biology behavior [15,105,114,118,119] and favorable mechanical properties [99,102,105], bioactive glassceramic scaffolds have shown superior in vivo behavior (e.g., bone formation, mineralization, higher interfacial strength between implant and bone) compared to the glass in particulate form [113] or compared to other bioactive materials (HA, tricalcium phosphate) [52].…”

45S5-Bioglass®-Based 3D-Scaffolds Seeded with Human Adipose Tissue-Derived Stem Cells Induce In Vivo Vascularization in the CAM Angiogenesis Assay

“…Recent in vivo studies using different animal models described an effect of 45S5 Bioglass Ò on the angiogenic response in soft connective and bone tissue. 16 Ghosh et al 19 and Nandi et al…”