Development of a bone substitute material based on alpha-tricalcium phosphate scaffold coated with carbonate apatite/poly-epsilon-caprolactone

Interconnected porous tricalcium phosphate ceramics are considered to be potential bone substitutes. However, insufficient mechanical properties when using tricalcium phosphate powders remain a challenge. To mitigate these issues, we have developed a new approach to produce an interconnected alpha-tricalcium phosphate (alpha-TCP) scaffold and to perform surface modification on the scaffold with a composite layer, which consists of hybrid carbonate apatite / poly-epsilon-caprolactone (CO(3)Ap/PCL) with enhanced mechanical properties and biological performance. Different CO(3)Ap combinations were tested to evaluate the optimal mechanical strength and in vitro cell response of the scaffold. The alpha-TCP scaffold coated with CO(3)Ap/PCL maintained a fully interconnected structure with a porosity of 80% to 86% and achieved an improved compressive strength mimicking that of cancellous bone. The addition of CO(3)Ap coupled with the fully interconnected microstructure of the alpha-TCP scaffolds coated with CO(3)Ap/PCL increased cell attachment, accelerated proliferation and resulted in greater alkaline phosphatase (ALP) activity. Hence, our bone substitute exhibited promising potential for applications in cancellous bone-type replacement.