Toughening of porous bioceramic scaffolds by bioresorbable polymeric coatings

The mechanical properties of poly(epsilon-caprolactone) (PCL)-coated porous bioceramic scaffolds made of calcium phosphates were studied and analysed using a statistical experimental design and Taguchi methods. In this study, both the flexural strength of the coated scaffolds and the amount of deposited PCL were considered as the measured responses. A statistical experimental design using the analysis of means and orthogonal array was applied to optimize these responses. The removal technique of excess polymer Solution, the concentration of PCL in the solution, a heat treatment temperature, and the number of times that the scaffolds were dipped in the solution were chosen as the significant processing variables. The removal technique of excess polymer solution and the number of times that the scaffolds were dipped in the solution showed the major effects on the flexural strength, while the technique for removal of excess polymer solution was found to have the major effect on the mass of the deposited PCL. The optimal conditions for achieving the maximal flexural strength of the coated scaffolds at the minimal amount of the deposited PCL were determined and tested. High-quality porous bioresorbable scaffolds with approximately 19 MPa flexural strength and approximately 0.4g of the total (PCL coating + calcium phosphates) mass with dimensions of 8.5 mm diameter and 13 mm width were manufactured as a result.