Three dimensional polyurethane/ hydroxyapatite bioactive scaffolds: The role of hydroxyapatite on pore generation

Abstract Fabrication of a suitable scaffold with highly interconnected and well‐distributed pores for cell proliferation and growth in the field of bone tissue engineering is of high importance. In this study, three‐dimensional porous polyurethane (PU) scaffolds, with 0, 15, 25, and 32 wt% hydroxyapatite (HA), were fabricated. In this regard, HA was incorporated into PU constituents prior to starting in‐situ polymerization of PU. Porosity and density measurement of the scaffolds revealed that higher amount of HA in the scaffolds led to increasing the former and decreasing the latter quantity. The field emission scanning electron microscopy (FESEM) images revealed that by increasing HA content, the pore size showed a descending trend while the number of pores increased. This would be attributed to the type of interactions between HA and PU, and the role of HA in pore formation. Mechanical test revealed that Young's Modulus of the samples was reduced by increasing scaffold porosity caused by the increase of HA content. Bioactivity tests in the simulated body fluid (SBF) showed the ability of scaffolds forming apatite precipitates. MTT assay showed that by increasing HA content, MG63 osteoblast cell viability increased and FESEM images revealed proper attachment of the cells to the scaffold surface.