Robocasting of single and multi-functional calcium phosphate scaffolds and its hybridization with conventional techniques: design, fabrication and characterization

Mehdi Mohammadi (1) , Patricia Pascaud-Mathieu (2) , Valeria Allizond (3) , Jean-Marc Tulliani (1) , Bartolomeo Coppola (1) , Giuliana Banche (3) , Christophe Chaput (4) , Anna Maria Cuffini (3) , Fabrice Rossignol (5) , Paola Palmero (1)

1 DISAT - Department of Applied Science and Technology [Politecnico di Torino]
2 IRCER-AXE4 - IRCER - Axe 4 : céramiques sous contraintes environnementales
3 UNITO - Università degli studi di Torino = University of Turin
4 3D-Ceram Company (Sinto Group)
5 IRCER-AXE1 - IRCER - Axe 1 : procédés céramiques

In this work, dense, porous and, for the first time, functionally-graded bi-layer scaffolds with a cylindrical geometry were produced from a commercially available hydroxyapatite powder using the robocasting technique. The bi-layer scaffolds were made of a dense core part attached to a surrounding porous part. Subsequently, these bi-layer robocast scaffolds were joined with an outer shell of an antibacterial porous polymer layer fabricated by solvent casting/salt leaching techniques, leading to hybrid ceramic-polymer scaffolds. The antibacterial functionality was achieved through the addition of silver ions to the polymer layer. All the robocast samples, including the bi-layer ones, were first characterized through scanning electron microscopy observations, mechanical characterization in compression and preliminary bioactivity tests. Then, the hybrid bi-layer ceramic-polymer scaffolds were characterized through antimicrobial tests. After sintering at 1300 °C for 3 h, the compressive strengths of the structures were found to be equal to 29 ± 4 MPa for dense samples and 7 ± 4 MPa for lattice structures with a porosity of 34.1%. Bioactivity tests performed at 37 °C for 4 weeks showed that the precipitated layer on the robocast samples contained octacalcium phosphate. Finally, it was evidenced that the hybrid structure was effective in releasing antibacterial Ag+ ions to the surrounding medium showing its potential efficiency in limiting Staphylococcus aureus proliferation during surgery.

Domaines: Matériaux

Mehdi Mohammadi, Patricia Pascaud-Mathieu, Valeria Allizond, Jean-Marc Tulliani, Bartolomeo Coppola, et al.. Robocasting of single and multi-functional calcium phosphate scaffolds and its hybridization with conventional techniques: design, fabrication and characterization. Applied Sciences, 2020, 10 (23), pp.8677. ⟨10.3390/app10238677⟩. ⟨hal-03039117⟩