Final Activity Report Summary - NEWEXTLIFESCAFF (Development of Extended-Lifetime Organic-Inorganic Scaffolds for Orthopaedical Applications)
A new generation of biomaterials for orthopaedic applications was developed. A novel processing technique, called robocasting or direct-write assembly, was successfully applied to fabricate porous bioceramic (hydroxyapatite and 61472 and 61538 tricalcium phosphate) scaffolds for bone tissue engineering.
The scaffolds consisted of a three-dimensional network of perfectly joined calcium phosphate rods fabricated in a pre-determined geometry. This was achieved by the computer-controlled robotic deposition of dense water-based suspensions of calcium phosphate powders capable of supporting their own weight. The calcium phosphate scaffold encouraged bone cells to proliferate into its designed pore structure, helping the body to regenerate a damaged tissue region after its implantation. The processing technique that was used had significant advantages over more conventional techniques for fabricating porous scaffolds that did not allow for a precise control of their three-dimensional external shape and internal morphology, as well as over other technologies capable of producing analogous controlled structures, such as stereolithography, three-dimensional printing etc, in terms of simplicity and cost. Moreover, it avoided the use of potentially toxic binders.
Calcium phosphate scaffolds were inherently brittle and this study allowed us to identify the damage modes occurring in the scaffold structures. Computer finite element models of the scaffolds were developed to calculate and predict their mechanical behaviour as a function of the different geometrical variables that could be controlled in the fabrication procedure. These computer models were anticipated to allow us to optimise in the near future the geometrical design of the scaffolds in order to improve their mechanical performance for load-bearing orthopaedic applications.
Finally, the mechanical performance of the scaffold could be greatly improved via infiltration of the porous structure with biodegradable polymers, such as polylactic acid, polyglycolic acid, polycaprolactone etc, to create a composite. The degradation of the polymer after implantation would create in situ the necessary porosity for bone in-growth into the composite scaffolds. This possibility opened up a most promising, and yet unexplored, way to create damage tolerant scaffolds for load bearing applications in bone tissue engineering. The viability of this concept was preliminarily explored in this project with very promising results, though additional work was still needed to bring this concept to reality.
The scaffolds consisted of a three-dimensional network of perfectly joined calcium phosphate rods fabricated in a pre-determined geometry. This was achieved by the computer-controlled robotic deposition of dense water-based suspensions of calcium phosphate powders capable of supporting their own weight. The calcium phosphate scaffold encouraged bone cells to proliferate into its designed pore structure, helping the body to regenerate a damaged tissue region after its implantation. The processing technique that was used had significant advantages over more conventional techniques for fabricating porous scaffolds that did not allow for a precise control of their three-dimensional external shape and internal morphology, as well as over other technologies capable of producing analogous controlled structures, such as stereolithography, three-dimensional printing etc, in terms of simplicity and cost. Moreover, it avoided the use of potentially toxic binders.
Calcium phosphate scaffolds were inherently brittle and this study allowed us to identify the damage modes occurring in the scaffold structures. Computer finite element models of the scaffolds were developed to calculate and predict their mechanical behaviour as a function of the different geometrical variables that could be controlled in the fabrication procedure. These computer models were anticipated to allow us to optimise in the near future the geometrical design of the scaffolds in order to improve their mechanical performance for load-bearing orthopaedic applications.
Finally, the mechanical performance of the scaffold could be greatly improved via infiltration of the porous structure with biodegradable polymers, such as polylactic acid, polyglycolic acid, polycaprolactone etc, to create a composite. The degradation of the polymer after implantation would create in situ the necessary porosity for bone in-growth into the composite scaffolds. This possibility opened up a most promising, and yet unexplored, way to create damage tolerant scaffolds for load bearing applications in bone tissue engineering. The viability of this concept was preliminarily explored in this project with very promising results, though additional work was still needed to bring this concept to reality.