Papers by Author: Sylvain Deville

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Authors: J. Russias, Eduardo Saiz, Sylvain Deville, Antoni P. Tomsia
Abstract: The development of novel biodegradable scaffolds for the treatment of bone and cartilage defects is the subject of intense research. A successful scaffold will guide cell-attachment, proliferation and tissue regeneration. The objective of this study is to use freeform fabrication (robocasting) for the preparation of porous hybrid organic/inorganic materials with a well controlled architecture and porosity. Polymer/hydroxyapatite (HA) pastes with ceramic contents ranging between 0 to 70 wt. % are prepared by mixing ceramic powders with a solution of the polymer in methylene chloride. Two different polymers are studied: polylactide (PLA) and polycaprolactone (PCL). During the compression tests, the scaffolds show an elasto-plastic behavior with large plastic yielding and do not fail in a brittle manner. The mechanical response is anisotropic and depends significantly on the ceramic content and the type of polymer.
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Authors: Sylvain Deville, Eduardo Saiz, Ravi K. Nalla, Antoni P. Tomsia
Abstract: Despite extensive efforts in the development of fabrication methods to prepare porous ceramic scaffolds for osseous tissue regeneration, all porous materials have a fundamental limitation- the inherent lack of strength associated with porosity. Shells (nacre), tooth and bone are frequently used as examples for how nature achieves strong and tough materials made out of weak components. So, the unresolved engineering dilemma is how to create a scaffold that is both porous and strong. The objective of this study was to mimic the architecture of natural materials in order to create a new generation of strong hydroxyapatite-based porous scaffolds. The porous inorganic scaffolds were fabricated by the controlled freezing of water-based hydroxyapatite (HA) slurries. The scaffolds obtained by this process have a lamellar architecture that exhibits similarities with the meso- and micro- structure of the inorganic component of nacre. Compressive strengths of 20 MPa were measured for lamellar scaffolds with densities of 32%, significantly better than for the HA with random porosity. In addition, the lamellar materials exhibit gradual fracture unlike conventional porous HA scaffolds. These biomimetic scaffolds could be the basis for a new generation of porous and composite biomaterials.
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