Speaker
Description
Calcium phosphate scaffolds have been widely studied in the last decades as valuable solution for bone regeneration. However, the design and preparation of large bioceramic scaffolds for load-bearing applications, provided with tailored porosity, still represents a remarkable challenge. On the other hand, their porosity, pore size distribution and interconnection strongly reflect their bioactivity and osteoconductivity in vivo, that is the capacity of the scaffold to promote cell migration and proliferation.
Several methods are reported to produce porous scaffolds, including replica, sacrificial template and direct foaming [1]. In addition, the 3D Printing technology, which involves the extrusion of a bioceramic suspension as a filament following a three-dimensional project, has also shown itself short of preparing scaffolds with controlled porosity.
The issue comes around as all these techniques are based on the manipulation of slurries, that is highly concentrated powder suspensions with critical processing. In this context, a detailed rheological characterization of bioceramic suspensions is highly desired. For example, it was reported that the thermal calcination of the powder and the amount of dispersant agents significantly affect both the viscoelasticity of the slurry and the final properties of the scaffold.
In this work, concentrated hydroxyapatite (HA)-based slurries were prepared, while evaluating the effect of calcination treatment (800 and 1000°C), concentrations of powder (45, 60 and 75 wt%) and dispersing agent (3, 4 and 5 wt%) on the rheological properties of the suspensions. The stability of suspensions was monitored by pH and ζ-potential measurements, while both viscosity and viscoelasticity tests were performed.
The stability of the suspensions was mainly affected by the calcination temperature, while the effect of the dispersant becomes significant with increasing the powder concentration.
[1] Studart et al., Processing Routes to Macroporous Ceramics: A Review, J. Am. Ceram. Soc., 89 [6] 1771–1789 (2006)
| Speaker Country | Italy |
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