Ex Vivo and In Vivo Analyses of Novel 3D-Printed Bone Substitute Scaffolds Incorporating Biphasic Calcium Phosphate Granules for Bone Regeneration

Abstract

(1) Background: The aim of this study was examining the ex vivo and in vivo properties of a composite made from polycaprolactone (PCL) and biphasic calcium phosphate (BCP) (synprint, ScientiFY GmbH) fabricated via fused deposition modelling (FDM); (2) Methods: Scaffolds were tested ex vivo for their mechanical properties using porous and solid designs. Subcutaneous implantation model analyzed the biocompatibility of PCL + BCP and PCL scaffolds. Calvaria implantation model analyzed the osteoconductive properties of PCL and PCL + BCP scaffolds compared to BCP as control group. Established histological, histopathological and histomorphometrical methods were performed to evaluate new bone formation.; (3) Results Mechanical testing demonstrated no significant differences between PCL and PCL + BCP for both designs. Similar biocompatibility was observed subcutaneously for PCL and PCL + BCP scaffolds. In the calvaria model, new bone formation was observed for all groups with largest new bone formation in the BCP group, followed by the PCL + BCP group, and the PCL group. This finding was influenced by the initial volume of biomaterial implanted and remaining volume after 90 days. All materials showed osteoconductive properties and PCL + BCP tailored the tissue responses towards higher cellular biodegradability. Moreover, this material combination led to a reduced swelling in PCL + BCP; (4) Conclusions: Altogether, the results show that the newly developed composite is biocompatible and leads to successful osteoconductive bone regeneration. The new biomaterial combines the structural stability provided by PCL with bioactive characteristics of BCP-based BSM. 3D-printed BSM provides an integration behavior in accordance with the concept of guided bone regeneration (GBR) by directing new bone growth for proper function and restoration.

The Granule Size Mediates the In Vivo Foreign Body Response and the Integration Behavior of Bone Substitutes

“…The histopathological analysis was performed on basis of a previously described protocol via a light microscope (Axio.Scope.A1, Zeiss, Oberkochen, Germany) [ 19 ]. In brief, this examination focused on the occurrence of the following parameters: fibrosis; hemorrhage; necrosis; vascularization; and the presence of neutrophils, lymphocytes, plasma cells, macrophages, and multinucleated giant cells.…”

Modified Histopathological Protocol for Poly-ɛ-Caprolactone Scaffolds Preserving Their Trabecular, Honeycomb-like Structure

“…The elements of the scaffold visible in these images, in contrast to those obtained in our study, were fused, melted, and swollen. Moreover, the trabecular structure of the scaffold with its fibers arranged in a honeycomb-like structure was not visible [ 35 ]. The same histopathological technique was used by Yun et al They investigated a bone-derived decellularized extracellular matrix (bdECM) and tricalcium phosphate (TCP), individually and in combination, as an osteogenic promoter between bone and a 3D-printed PCL scaffold in rat calvarial defects.…”

Recent Advances in Engineering Bioinks for 3D Bioprinting

“…Paclitaxel‐loaded PCL‐OX microspheres have been found to be rapidly degraded in vivo within 28 d while maintaining a stable plasma drug concentration. [ 136 ] In addition, PCL is commonly used for printing bone, [ 137 ] blood vessel, [ 138 ] skin, [ 139 ] cartilage, [ 140 ] and nerve [ 141 ] tissues and for developing drug delivery systems. [ 142 ] However, PCL is poorly soluble in water and cannot be used to encapsulate cells.…”