Preparation and cell infiltration of lotus-type porous nano-hydroxyapatite/polyurethane scaffold for bone tissue regeneration

The pore size, porosity and pore connectivity are important structural parameters that affect the mechanical strength and biological performance of a scaffold for bone tissue regeneration. A lotus-type porous nano-hydroxyapatite/polyurethane (n-HA/PU) scaffold was designed and fabricated, and its mechanical property and cell behavior were evaluated. The results showed that the scaffold had an anisotropic pore structure, the porosity was about 84% and the macropore size on cross-section was uniform, close to 600 µm. The mechanical properties also showed an anisotropic feature according to the oriented pore structure. When stress applied parallel to the pore orientation, the longitudinal compressive strength and elastic modulus were 3.52 MPa and 44.25 MPa respectively, much higher than the lateral 2.59 MPa and 10.42 MPa. Cell culture indicated that the lotus-type n-HA/PU scaffold exhibited good cell affinity and cytocompatibility, the proper pore size and high pore's connectivity were favourable for cell infiltration into the inner part of the scaffold. The lotus-type n-HA/PU scaffold has promising prospect in bone tissue regeneration field.