Composite scaffolds based on magnesium doped hydroxyapatite and mesoporous nanosized bioactive glass

Abstract

Bioceramic materials based on hydroxyapatite (HAP) are widely used as scaffolding material for bone tissue engineering due to their similarity with inorganic part of human bones. Magnesium ion as a dopant in hydroxyapatite was previously shown to improve mechanical properties of HAP based materials, as well as to improve osteoblasts cell proliferation, and induce angiogenesis which stimulate the bone regeneration. Mesoporous bioactive glass nanoparticles (MBGNPs) present the latest generation of the sol-gel glasses, having high surface area and large pore volume that allow the loading of drugs (antiinflammatory, anti-osteoporotic, anti-cancer etc.) and growth factors for stimulating cell differentiation and proliferation. MBGNPs are highly soluble and more bioactive compared to the hydroxyapatite. However, their high porosity leads to poor mechanical properties of pure MBGNP-based scaffolds. Here we propose composite scaffolds based on magnesium doped hydroxyapatite and MBGNPs obtained by a modified microemulsion-assisted sol-gel synthesis for bone tissue engineering application. Hydrothermally obtained hydroxyapatite doped with 5 mol. % of magnesium ions was calcinated at 1000 °C and mixed with 10-20 wt.% BGNPs to form composite scaffolds by sponge replica method. The addition of MBGNPs has the influence on the sinterability, mechanical properties and bioactivity of the scaffolds.