S. Raymond et al. Accelerated hardening of nanotextured 3D-plotted self-setting calcium phosphate inks. Acta Biomaterialia

S. Raymond, Y. Maazouz, E.B. Montufar, R.A. Perez, B. González, J. Konka, J. Kaiser, M.P. Ginebra. Accelerated hardening of nanotextured 3D-plotted self-setting calcium phosphate inks. Acta Biomaterialia 75 (2018) 451–462. 

doi: doi.org/10.1016/j.actbio.2018.05.042

Abstract

Direct ink writing (DIW) techniques open up new possibilities for the fabrication of patient-specific bone grafts. Self-setting calcium phosphate inks, which harden at low temperature, allow obtaining nanostructured scaffolds with biomimetic properties and enhanced bioactivity. However, the slow hardening kinetics hampers the translation to the clinics. Different hydrothermal treatments for the consolidation of DIW scaffolds fabricated with an α-tricalcium phosphate /pluronic F127 ink were explored, comparing them with a biomimetic treatment. Three different scaffold architectures were analysed. The hardening process, associated to the conversion of α-tricalcium phosphate to hydroxyapatite was drastically accelerated by the hydrothermal treatments, reducing the time for complete reaction from 7 days to 30 minutes, while preserving the scaffold architectural integrity and retaining the nanostructured features. β-tricalcium phosphate was formed as a secondary phase, and a change of morphology from plate-like to needle-like crystals in the hydroxyapatite phase was observed. The binder was largely released during the treatment. The hydrothermal treatment resulted in a 30% reduction of the compressive strength, associated to the residual presence of β-tricalcium phosphate. Biomimetic and hydrothermally treated scaffolds supported the adhesion and proliferation of rat mesenchymal stem cells, indicating a good suitability for bone tissue engineering applications.