Porous 3D Printed Scaffolds For Guided Bone Regeneration In a Rat Calvarial Defect Model

The application of 3D printed scaffolds for bone tissue regeneration has been explored in previous studies. In this study, we combined 3D printing with porogen leaching to develop scaffolds with dual-scale porosity and investigated their capability in guided bone regeneration in a rat critical size calvarial defect model. The scaffolds were additively manufactured from medical grade polycaprolactone (mPCL) doped with porogen microparticles having an average size of 22 μm, which were subsequently leached to create microscale porosity. Morphological analysis revealed an interconnected macroscale porosity of about 60% with an average pore size of 700 µm and intra-strut microscale pores with a porosity of nearly 40% and average pore size of 20–70 µm. The microscale porosity resulted in a 3-fold increase in the scaffolds’ surface area, a 2-fold enrichment in negatively charged surface groups, which did lead to significantly increased protein adsorption and faster hydrolysis-driven degradation in vitro. An in vitro blood clotting assay demonstrated an increased TGF-β1 release from the clots formed on the dual-scale porous scaffolds. In a rat calvarial defect, bone formation was found in both the macro- and microscale pores and was at a similar level when compared to calcium phosphate coated mPCL scaffolds.