Controlled delivery of icariin on small intestine submucosa for bone tissue engineering

Small intestine submucosa (SIS) has been reported as an excellent biomaterial for tissue engineering because of its naturally occurring collagenous extracellular matrix property with growth factors. However, SIS from submucosal layer of intestine provides different microenvironment from bone tissue, which limits its application to bone regeneration. The object of this study was to improve osteoinductivity of SIS by controlled local delivery of icariin (Ic), a potent osteogenic compound. Sustained release of icariin from SIS scaffold was achieved for >30days and the loading of icariin on SIS scaffold was uniform as scanned by SEM. In vitro experiments revealed that expression of osteogenic differentiation markers (Alp, Bsp and Ocn) was increased after treatment of Ic-SIS scaffold, without significant cytotoxicity. In an in vivo mouse calvarial defect model, bone regeneration was enhanced by SIS implantation at 8weeks, compared to control defect. New bone formation was further improved by implantation with Ic-SIS (low and high) at both 4 and 8weeks. The results of this study suggest that SIS scaffold has the potential as an icariin delivery carrier for enhancement of bone regeneration.