Interaction of endothelial cells with biodegradable strontium-doped calcium polyphosphate for bone tissue engineering

Angiogenesis is of great importance in bone tissue engineering, and has gained large attention in the recent 10 years. However, little research has been done on the effect of biodegradable materials, especially their degradation products on the angiogenesis process. Strontium-doped calcium polyphosphate (SCPP) has been proved to be able to promote osteoblasts growth in vitro before. In the present work, the interaction of endothelial cells (ECs) with the scaffold of SCPP was investigated to evaluate its potential influences on angiogenesis. The cell adhesion on SCPP scaffold as well as the angiogenic behaviors including proliferation, migration and tube-like structure (TLS) formation of ECs treated by its degradation products was tested. The results were compared with those of CPP group and physiological saline (negative control). As the results showed, the surface of SCPP could promote the adhesion and spreading of ECs. Ca2+ and Pi as well as Sr2+ were the main degradation products of SCPP. They did not inhibit but could promote the proliferation of ECs within 90 days. Moreover, they could induce the migration and TLS formation of ECs. Since SCPP bears the ability to improve the adhesion and angiogenic behaviors of endothelial cells, it might benefit angiogenesis and serve as a more promising scaffold for bone tissue engineering application. Besides, this work may provide a new method for in vitro evaluation of biodegradable materials' potential effects on angiogenesis.