Production and characterisation of porous calcium phosphate structures with controllable hydroxyapatite/ β -tricalcium phosphate ratios

Because bone tissue engineering (TE) strategies encounter patient specificities, like site of implantation and different bone turnover rate, scaffolds with tunable characteristics are required. With this regard, custom made open porous calcium phosphate (CaP) structures with variable chemical and structural compositions were produced using an optimised gel casting technique. The phase composition was altered by changing the initial hydroxyapatite (HA) to β-tricalcium phosphate (β-TCP) powder ratio. After sintering, an HA/β-TCP ratio between 100 : 0 and 0 : 100 was predictably attained. Average pore sizes ranged from 182 to 466 m m and corresponded to porosity values of respectively 71 and 86%. Mechanical strength and dynamic E-modulus respectively decreased with decreasing HA content from 10·1 to 0·4 MPa and 9·46 to 0·27 GPa. It was concluded that this optimised gel casting method enables the production of CaP scaffolds with a custom made HA/β-TCP ratio with variable pore size, porosity and corresponding mechanical strength.