Adjustment of Micro- and Macroporosity of ß-TCP Scaffolds Using Solid-Stabilized Foams as Bone Replacement

Lukas Dufner; Bettina Oßwald; Jan Eberspaecher; Bianca Riedel; Chiara Kling; Frank Kern; Michael Seidenstuecker

doi:10.3390/bioengineering10020256

Adjustment of Micro- and Macroporosity of ß-TCP Scaffolds Using Solid-Stabilized Foams as Bone Replacement

Bioengineering (Basel). 2023 Feb 15;10(2):256. doi: 10.3390/bioengineering10020256.

Authors

Lukas Dufner¹, Bettina Oßwald¹, Jan Eberspaecher¹, Bianca Riedel², Chiara Kling², Frank Kern¹, Michael Seidenstuecker²

Affiliations

¹ Institute for Manufacturing Technologies of Ceramic Components and Composites, University of Stuttgart, 70569 Stuttgart, Germany.
² G.E.R.N. Center of Tissue Replacement, Regeneration & Neogenesis, Department of Orthopedics and Trauma Surgery, Medical Center-Albert-Ludwigs-University of Freiburg, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Hugstetter Straße 55, 79106 Freiburg, Germany.

Abstract

To enable rapid osteointegration in bioceramic implants and to give them osteoinductive properties, scaffolds with defined micro- and macroporosity are required. Pores or pore networks promote the integration of cells into the implant, facilitating the supply of nutrients and the removal of metabolic products. In this paper, scaffolds are created from ß-tricalciumphosphate (ß-TCP) and in a novel way, where both the micro- and macroporosity are adjusted simultaneously by the addition of pore-forming polymer particles. The particles used are 10-40 wt%, spherical polymer particles of polymethylmethacrylate (PMMA) (Ø = 5 µm) and alternatively polymethylsilsesquioxane (PMSQ) (Ø = 2 µm), added in the course of ß-TCP slurry preparation. The arrangement of hydrophobic polymer particles at the interface of air bubbles was incorporated during slurry preparation and foaming of the slurry. The foam structures remain after sintering and lead to the formation of macro-porosity in the scaffolds. Furthermore, decomposition of the polymer particles during thermal debindering results in the formation of an additional network of interconnecting micropores in the stabilizing structures. It is possible to adjust the porosity easily and quickly in a range of 1.2-140 μm with a relatively low organic fraction. The structures thus prepared showed no cytotoxicity nor negative effects on the biocompatibility.

Keywords: bioceramics; capillary suspension; foaming; polymer particles; sacrificial templating.

Grants and funding

This publication was funded by the German Research Foundation (DFG) grant “Open Access Publication Funding/2023–2024/University of Stuttgart” (512689491).