Evaluation of porous polyurethane scaffold on facilitating healing in critical sized bone defect

Abstract

Bone graft substitute is a continuously developing field in orthopedics. When compared to tradition biomaterial in the field such as PLA or PCL, elastomer like polyurethane offers advantages in its high elasticity and flexibility, which establish an intimate contact with surrounding bones. This tight contact can provide a stable bone-material interface for cell proliferation and ingrowth of bone. The aim of this study is to evaluate the osteogenesis capabilities of a porous polyurethane scaffold in a critical size bone defect. In this study, a porous scaffold synthesized from segmented polyurethane is put under in vitro and in vivo tests to evaluate its potential in acting as a bone graft substitute for critical size bone defects. In vitro results indicate osteoblast-like cells are proliferating on the polyurethane scaffold during the 21-days experiment. Cells express their normal morphology when seeded on polyurethane under fluorescent staining. Although cells show a relatively lower cell activity then that seeded on culture plate, they share a similar alkaline phosphatase activity profile with the controls during the experiment period. In the in vivo animal model, reconstructed images from micro CT scanning indicates there are bone ingrowth inside the scaffold. Histology also indicates a tight interface has formed between bone and polyurethane, with osteogenic cells proliferating on the surface. The result has indicates polyurethane is a potential material for orthopedics in acting as a bone graft substitute.