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

Franciska Oberdiek,Jose Manuel Baena,Carlos Ivan Vargas,Oliver Görke,Ole Jung,Stevo Najman,Mike Barbeck,Milena Radenković,Patrick Rider,Milijana Batinic

doi:10.3390/ijms22073588

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.

Highlights

The aim of bone regeneration is repairing a bony defect caused by a trauma, tumor, or disease
Biphasic compounds of CaP composed of hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP) are already used in the daily clinical practice due to their adapted degradation behavior that has shown to be favorable for the process of bone regeneration [6,7]
The analysis showed that significantly more biomaterial and connective tissue (CT) were found in the PCL+biphasic calcium phosphate (BCP)-group compared to the amount of newly formed bone (** p < 0.01 and *** p < 0.001) (Table 4 and Figure 11)

Summary

Introduction

The aim of bone regeneration is repairing a bony defect caused by a trauma, tumor, or disease. Bone augmentation can be achieved using biomaterials that function as an anchoring structure for new bone formation These bone augmentation materials are divided into autografts, allografts, xenografts, and synthetic materials. In contrast to natural bone grafts, synthetic materials can be provided in higher quantities with low risks of immunological reaction and rejection by the body [1]. Ceramic synthetic materials such as calcium phosphate (CaP) demonstrate excellent bioactivity and strong mechanical properties that make them ideal for use in bone tissue regeneration [5]. The possibilities of creating patient-individualized scaffolds from pure CaP are still limited in comparison to that of natural bone grafts, which can contain both mineral and collagen structures in a more durable structure [10]

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Conclusion