Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. II. In vitro and in vivo biological evaluation

Abstract

In Part I, the in vitro degradation of bioactivAR52115e glass scaffolds with a microstructure similar to that of human trabecular bone, but with three different compositions, was investigated as a function of immersion time in a simulated body fluid. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO2 content of 13-93 was replaced by B2O3, respectively. This work is an extension of Part I, to investigate the effect of the glass composition on the in vitro response of osteogenic MLO-A5 cells to these scaffolds, and on the ability of the scaffolds to support tissue infiltration in a rat subcutaneous implantation model. The results of assays for cell viability and alkaline phosphatase activity showed that the slower degrading silicate 13-93 and borosilicate 13-93B1 scaffolds were far better than the borate 13-93B3 scaffolds in supporting cell proliferation and function. However, all three groups of scaffolds showed the ability to support tissue infiltration in vivo after implantation for 6 weeks. The results indicate that the required bioactivity and degradation rate may be achieved by substituting an appropriate amount of SiO2 in 13-93 glass with B2O3, and that these trabecular glass scaffolds could serve as substrates for the repair and regeneration of contained bone defects.

Bioceramic Scaffolds

“…The ability of bioactive glass scaffolds to support cell proliferation and function in-vitro and tissue ingrowth in-vivo has been shown in numerous studies [115][116][117][118][119][120][121][122]. Fu et al showed that 13-93 bioactive glass scaffolds prepared using a polymer foam by replica method supported the attachment and proliferation of MC3T3-E1 preosteoblastic cells both on the surface and within the interior pores of the scaffold [115].…”

Design and Properties of Novel Substituted Borosilicate Bioactive Glasses and Their Glass-Ceramic Derivatives

“…Baiano et al 18 used bioactive 6 glass-based trabecular coating for the development of a novel prosthetic acetabular cup to have an 7 improved in vivo interfacial bond with bone. 8 While studies have been demonstrating the ability of BBGs to better control degradation, thus 9 increasing the beneficial properties of ions release, there are still concerns regarding toxicity when 10 those glasses are implanted 19,20 . There are several metal ions that at higher concentrations are 11 extremely toxic.…”

High Borate Networks as a Platform to Modulate Temporal Release of Therapeutic Metal Ions Gallium and Strontium

“…tumor embolization) [2][3][4][5]. Interestingly, and despite the exceptionally large number of non-crystalline solids (NCS) that can be synthesized from the useful elements on the periodic table of elements (estimates are upwards of 1.3 x 10 52 potential NCS), the compositional palette of bioactive glasses has largely focused on the silicate-based 45S5 glass, as a platform, for the continued development of new degradable bioactive glass systems [6][7][8].…”

“…However, more recently boron based-glasses, particularly those networks where B is the sole former, are increasingly investigated for medical applications [6][7][8][9]. Contrary to historical concerns regarding borate glasses' low chemical durability, several compositions have recently displayed excellent potential in hard tissue and soft tissue augmentation/repair, specifically, enabling accelerated bone remodeling and healing of chronic wounds (e.g.…”

“…Contrary to historical concerns regarding borate glasses' low chemical durability, several compositions have recently displayed excellent potential in hard tissue and soft tissue augmentation/repair, specifically, enabling accelerated bone remodeling and healing of chronic wounds (e.g. diabetic ulcers) [1,7,[9][10][11][12]. An interesting characteristic of vitreous boron oxides is its complete degradation.…”