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by Keyword: 3D-printing


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Barba, Albert, Maazouz, Yassine, Diez-Escudero, Anna, Rappe, Katrin, Espanol, Montserrat, Montufar, Edgar B., Öhman-Mägi, Caroline, Persson, Cecilia, Fontecha, Pedro, Manzanares, Maria-Cristina, Franch, Jordi, Ginebra, Maria-Pau, (2018). Osteogenesis by foamed and 3D-printed nanostructured calcium phosphate scaffolds: Effect of pore architecture Acta Biomaterialia 79, 135-147

There is an urgent need of synthetic bone grafts with enhanced osteogenic capacity. This can be achieved by combining biomaterials with exogenous growth factors, which however can have numerous undesired side effects, but also by tuning the intrinsic biomaterial properties. In a previous study, we showed the synergistic effect of nanostructure and pore architecture of biomimetic calcium deficient hydroxyapatite (CDHA) scaffolds in enhancing osteoinduction, i.e. fostering the differentiation of mesenchymal stem cells to bone forming cells. This was demonstrated by assessing bone formation after implanting the scaffolds intramuscularly. The present study goes one step forward, since it analyzes the effect of the geometrical features of the same CDHA scaffolds, obtained either by 3D-printing or by foaming, on the osteogenic potential and resorption behaviour in a bony environment. After 6 and 12 weeks of intraosseous implantation, both bone formation and material degradation had been drastically affected by the macropore architecture of the scaffolds. Whereas nanostructured CDHA was shown to be highly osteoconductive both in the robocast and foamed scaffolds, a superior osteogenic capacity was observed in the foamed scaffolds, which was associated with their higher intrinsic osteoinductive potential. Moreover, they showed a significantly higher cell-mediated degradation than the robocast constructs, with a simultaneous and progressive replacement of the scaffold by new bone. In conclusion, these results demonstrate that the control of macropore architecture is a crucial parameter in the design of synthetic bone grafts, which allows fostering both material degradation and new bone formation. Statement of Significance: 3D-printing technologies open new perspectives for the design of patient-specific bone grafts, since they allow customizing the external shape together with the internal architecture of implants. In this respect, it is important to design the appropriate pore geometry to maximize the bone healing capacity of these implants. The present study analyses the effect of pore architecture of nanostructured hydroxyapatite scaffolds, obtained either by 3D-printing or foaming, on the osteogenic potential and scaffold resorption in an in vivo model. While nanostructured hydroxyapatite showed excellent osteoconductive properties irrespective of pore geometry, we demonstrated that the spherical, concave macropores of foamed scaffolds significantly promoted both material resorption and bone regeneration compared to the 3D-printed scaffolds with orthogonal-patterned struts and therefore prismatic, convex macropores.

Keywords: Osteogenesis, Pore architecture, 3D-printing, Foaming, Calcium phosphate


Barba, A., Diez-Escudero, A., Maazouz, Y., Rappe, K., Espanol, M., Montufar, E. B., Bonany, M., Sadowska, J. M., Guillem-Marti, J., Öhman-Mägi, C., Persson, C., Manzanares, M. C., Franch, J., Ginebra, M. P., (2017). Osteoinduction by Foamed and 3D-Printed Calcium Phosphate Scaffolds: Effect of Nanostructure and Pore Architecture ACS Applied Materials & Interfaces , 9, (48), 41722-41736

Some biomaterials are osteoinductive, that is, they are able to trigger the osteogenic process by inducing the differentiation of mesenchymal stem cells to the osteogenic lineage. Although the underlying mechanism is still unclear, microporosity and specific surface area (SSA) have been identified as critical factors in material-associated osteoinduction. However, only sintered ceramics, which have a limited range of porosities and SSA, have been analyzed so far. In this work, we were able to extend these ranges to the nanoscale, through the foaming and 3D-printing of biomimetic calcium phosphates, thereby obtaining scaffolds with controlled micro- and nanoporosity and with tailored macropore architectures. Calcium-deficient hydroxyapatite (CDHA) scaffolds were evaluated after 6 and 12 weeks in an ectopic-implantation canine model and compared with two sintered ceramics, biphasic calcium phosphate and β-tricalcium phosphate. Only foams with spherical, concave macropores and not 3D-printed scaffolds with convex, prismatic macropores induced significant ectopic bone formation. Among them, biomimetic nanostructured CDHA produced the highest incidence of ectopic bone and accelerated bone formation when compared with conventional microstructured sintered calcium phosphates with the same macropore architecture. Moreover, they exhibited different bone formation patterns; in CDHA foams, the new ectopic bone progressively replaced the scaffold, whereas in sintered biphasic calcium phosphate scaffolds, bone was deposited on the surface of the material, progressively filling the pore space. In conclusion, this study demonstrates that the high reactivity of nanostructured biomimetic CDHA combined with a spherical, concave macroporosity allows the pushing of the osteoinduction potential beyond the limits of microstructured calcium phosphate ceramics.

Keywords: 3D-printing, Calcium phosphate, Foaming, Nanostructure, Osteoinduction


Serra, T., Ortiz-Hernandez, M., Engel, E., Planell, J. A., Navarro, M., (2014). Relevance of PEG in PLA-based blends for tissue engineering 3D-printed scaffolds Materials Science and Engineering: C 38, (1), 55-62

Achieving high quality 3D-printed structures requires establishing the right printing conditions. Finding processing conditions that satisfy both the fabrication process and the final required scaffold properties is crucial. This work stresses the importance of studying the outcome of the plasticizing effect of PEG on PLA-based blends used for the fabrication of 3D-direct-printed scaffolds for tissue engineering applications. For this, PLA/PEG blends with 5, 10 and 20% (w/w) of PEG and PLA/PEG/bioactive CaP glass composites were processed in the form of 3D rapid prototyping scaffolds. Surface analysis and differential scanning calorimetry revealed a rearrangement of polymer chains and a topography, wettability and elastic modulus increase of the studied surfaces as PEG was incorporated. Moreover, addition of 10 and 20% PEG led to non-uniform 3D structures with lower mechanical properties. In vitro degradation studies showed that the inclusion of PEG significantly accelerated the degradation rate of the material. Results indicated that the presence of PEG not only improves PLA processing but also leads to relevant surface, geometrical and structural changes including modulation of the degradation rate of PLA-based 3D printed scaffolds.

Keywords: 3D-printing, Polylactic acid, Rapid prototyping, Scaffold, Surface characterization