Toughening 3D printed biomimetic hydroxyapatite scaffolds: Polycaprolactone-based self-hardening inks
Por:
del Mazo-Barbara L, Johansson L, Tampieri F and Ginebra MP
Publicada:
15 mar 2024
Ahead of Print:
1 mar 2024
Resumen:
The application of 3D printing to calcium phosphates has opened unprecedented possibilities for the fabrication of personalized bone grafts. However, their biocompatibility and bioactivity are counterbalanced by their high brittleness. In this work we aim at overcoming this problem by developing a self -hardening ink containing reactive ceramic particles in a polycaprolactone solution instead of the traditional approach that use hydrogels as binders. The presence of polycaprolactone preserved the printability of the ink and was compatible with the hydrolysis -based hardening process, despite the absence of water in the ink and its hydrophobicity. The microstructure evolved from a continuous polymeric phase with loose ceramic particles to a continuous network of hydroxyapatite nanocrystals intertwined with the polymer, in a configuration radically different from the polymer/ceramic composites obtained by fused deposition modelling. This resulted in the evolution from a ductile behavior, dominated by the polymer, to a stiffer behavior as the ceramic phase reacted. The polycaprolactone binder provides two highly relevant benefits compared to hydrogel-based inks. First, the handleability and elasticity of the as -printed scaffolds, together with the proven possibility of eliminating the solvent, opens the door to implanting the scaffolds freshly printed once lyophilized, while in a ductile state, and the hardening process to take place inside the body, as in the case of calcium phosphate cements. Second, even with a hydroxyapatite content of more than 92 wt.%, the flexural strength and toughness of the scaffolds after hardening are twice and five times those of the all -ceramic scaffolds obtained with the hydrogel-based inks, respectively. Statement of significance Overcoming the brittleness of ceramic scaffolds would extend the applicability of synthetic bone grafts to high load -bearing situations. In this work we developed a 3D printing ink by replacing the conventional hydrogel binder with a water -free polycaprolactone solution. The presence of polycaprolactone not only enhanced significantly the strength and toughness of the scaffolds while keeping the proportion of bioactive ceramic phase larger than 90 wt.%, but it also conferred flexibility and manipulability to the as -printed scaffolds. Since they are able to harden upon contact with water under physiological conditions, this opens up the possibility of implanting them immediately after printing, while they are still in a ductile state, with clear advantages for fixation and press -fit in the bone defect. (c) 2024 The Authors. Published by Elsevier Ltd on behalf of Acta Materialia Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )
Filiaciones:
del Mazo-Barbara L:
Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Engineering and Research Centre for Biomedical Engineering, Universitat Politècnica de Catalunya. BarcelonaTech (UPC), Barcelona, Spain
Barcelona Research Centre in Multiscale Science and Engineering, UPC, Barcelona, Spain
Institut de Recerca Sant Joan de Déu, Barcelona, Spain
Johansson L:
Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Engineering and Research Centre for Biomedical Engineering, Universitat Politècnica de Catalunya. BarcelonaTech (UPC), Barcelona, Spain
Barcelona Research Centre in Multiscale Science and Engineering, UPC, Barcelona, Spain
Institut de Recerca Sant Joan de Déu, Barcelona, Spain
Mimetis Biomaterials S.L., Barcelona, Spain
Tampieri F:
Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Engineering and Research Centre for Biomedical Engineering, Universitat Politècnica de Catalunya. BarcelonaTech (UPC), Barcelona, Spain
Barcelona Research Centre in Multiscale Science and Engineering, UPC, Barcelona, Spain
Institut de Recerca Sant Joan de Déu, Barcelona, Spain
CIBER de Bioingeniería, Biomateriales y Nanomedicina, Instituto de Salud Carlos III
Ginebra MP:
Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Engineering and Research Centre for Biomedical Engineering, Universitat Politècnica de Catalunya. BarcelonaTech (UPC), Barcelona, Spain
Barcelona Research Centre in Multiscale Science and Engineering, UPC, Barcelona, Spain
CIBER de Bioingeniería, Biomateriales y Nanomedicina, Instituto de Salud Carlos III
Institute for Bioengineering of Catalonia (IBEC), Barcelona Institute of Science and Technology, Barcelona, Spain
Green Submitted, hybrid
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