Porous akermanite scaffolds for bone tissue engineering: preparation, characterization, and in vitro studies

The aim of this study was to develop a bioactive, degradable, and cytocompatible akermanite (Ca2MgSi2O7) scaffold with high porosity and pore interconnectivity. In brief, porous akermanite scaffolds were prepared using polymer sponge method. The porosity and corresponding compressive strength were evaluated. The in vitro degradability was investigated by soaking the scaffolds in Ringer's solution. Hydroxyapatite (HAp)-formation ability of akermantite scaffolds in simulated body fluid (SBF) and the effect of ionic products from the scaffolds dissolution on osteoblasts were investigated. In addition, bone marrow stromal cells (BMSC) adhesion and proliferation on the scaffolds were evaluated. Differentiation of the cells was assessed by measuring alkaline phosphatase (ALP) activity. The results showed that akermanite scaffolds possessed 63.5-90.3% of porosity, with a corresponding compressive strength between 1130 and 530 kPa. The weight loss of the scaffolds and ionic content of the Ringer's solution increased with the increase in soaking time, indicating the degradability of scaffolds. HAp was formed on the scaffolds in SBF and the ionic products from akermanite scaffolds dissolution stimulated osteoblasts proliferation, indicating good in vitro bioactivity. Furthermore, BMSC adhered and spread well on akermanite scaffolds and proliferated with the increase in the culture time, and the differentiation rate of osteoblasts on scaffolds was comparable to that on blank culture plate control. Our results suggested that akermanite scaffolds were bioactive, degradable, and cytocompatible, and might be used as bone tissue engineering materials.