Porous scaffolds for bone regeneration

Globally, bone fractures due to osteoporosis occur every 20 s in people aged over 50 years. The significant healthcare costs required to manage this problem are further exacerbated by the long healing times experienced with current treatment practices. Novel treatment approaches such as tissue engineering, is using biomaterial scaffolds to stimulate and guide the regeneration of damaged tissue that cannot heal spontaneously. Scaffolds provide a three-dimensional network that mimics the extra cellular micro-environment supporting the viability, attachment, growth and migration of cells whilst maintaining the structure of the regenerated tissue in vivo. The osteogenic capability of the scaffold is influenced by the interconnections between the scaffold pores which facilitate cell distribution, integration with the host tissue and capillary ingrowth. Hence, the preparation of bone scaffolds with applicable pore size and interconnectivity is a significant issue in bone tissue engineering. To be effective however in vivo, the scaffold must also cope with the requirements for physiological mechanical loading. This review focuses on the relationship between the porosity and pore size of scaffolds and subsequent osteogenesis, vascularisation and scaffold degradation during bone regeneration.