Bioactive glass–gelatin hybrids: building scaffolds with enhanced calcium incorporation and controlled porosity for bone regeneration

Abstract

Thanks to their active promotion of bone formation, bioactive glasses (BG) offer unique properties for bone regeneration, but their brittleness prevents them from being used in a wide range of applications.

Optimized Bioactive Glass: the Quest for the Bony Graft

“…Calcium incorporation could be achieved with Ca(NO 3 ) 2 by heating the dried gels above 400 °C , and toxic nitrates were also burnt off at this temperature . In contrast, calcium ions incorporate the glass network at room temperature when employing calcium alkoxides (Ca(OR) 2 where R is an alkyl group) as sol–gel precursors, as demonstrated in many studies on sol–gel derived BAG‐based materials involving calcium methoxyethoxide and calcium ethoxide . Silicate glasses obtained by sol–gel chemistry differ from melt‐quenched glasses in terms of structure.…”

“…Recently, Lao et al developed a protocol that allows the synthesis of BAG‐gelatin class‐II hybrid scaffolds with Ca(OEt) 2 as the calcium source . The gelation of the hybrid solution was delayed to 2 h by using a reduced water‐to‐tetraethylorthosilicate molar ratio of two under dilute conditions.…”

Mechanism of Calcium Incorporation Inside Sol–Gel Silicate Bioactive Glass and the Advantage of Using Ca(OH)2 over Other Calcium Sources

“…6-8 Even though BG-pol ym er hybrid scaffolds appear as promising bone substitutes, their development is hindered by the difficulty of incorporating calcium ions into the BG silicate network. Calcium pla ys a central role in the bioactivity of BG 9 and its release is known to favor the adsorption of proteins involved in osteogenic processes and infi ammatory response, 10 and to induce osteoblast proliferation and differentiation.11 Traditionally, sol-gel BG are prepared from salts like CaG 2 or Ca(NO 3 ) 21 but these calcium sources require a thermal treatment above 400 °C to allow calcium to enter the silicate network and to remove the counterion, as this has been well established in pioneering works by Lin, Y u, and Jones et al 12•13 In the synthesis of hybrids, the presence of a pol ym er at an early stage of the sol-gel process forbids such thermal treatments; as a consequence, hybrids prepared from calcium salts are likely made of a pure silica-pol ym er hybrid in which the silicate network is coated with these salts.…”

One‐Pot Fabrication of Poly(ε‐Caprolactone)‐Incorporated Bovine Serum Albumin/Calcium Alginate/Hydroxyapatite Nanocomposite Scaffolds by High Internal Phase Emulsion Templates

“…[1][2][3][4] For achieving the goals of tissue engineering, one of the major issues is to fabricate appropriate porous scaffolds as tissue substitutes. [5][6][7][8][9] These porous scaffolds can not only offer a suitable environment for the delivery of cells into the damaged or diseased tissues, but also can serve as a template for the repair and regeneration of tissues. In essence, the ideal porous scaffolds used in tissue engineering must satisfy certain specific requirements, such as good biocompatibility, high porosity, and pore interconnectivity, suitable mechanical properties, controlled biodegradability, excellent drug and/or growth factor loading and sustained release ability.…”