Titanium Bone Scaffolds

The treatment of large bone defects still poses a major challenge in orthopaedic and craniomaxillafacial surgery. One possible solution is the development of personalized porous titanium based implants, designed to meet all mechanical needs with a minimum amount of titanium and maximum of osteopromotive properties.

In this project, we developed specific designs of unit cells to fill out bony defect site with an open-porous lattice structure. The mechanic response of the scaffold depends on the chosen lattice architecture. This is of great importance for mimic human bone by titanium scaffolds in order to reduce stress shielding. The designed titanium scaffolds are 3D-printed by selective laser melting and then implanted into calvarial defects in rabbits to examine bone formation and osseointegration. Significant differences are noted between defects filled with implants and untreated defects. The studies further aimed to apply SLM that allows a high degree of microarchitectural freedom to generate lattice structures and to determine the optimal distance between rods and the optimal diameter of rods for osteoconduction (bone ingrowth into scaffolds) and bone regeneration. For the biological readout, diverse SLM-fabricated titanium implants were placed in the calvarium of rabbits and new bone formation and defect bridging were determined after 4 weeks of healing. To link 3D scaffold architecture to biological readouts, bone ingrowth, bone to implant contact, and defect bridging of noncritical-sized defects in the calvarial bone of rabbits were determined. We further elucidated the optimal microarchitecture for osteoconduction and determine compression strength and Young’s Modulus of the selected architectures.

3D-printed titanium scaffolds_2.png

3D-printed titanium scaffolds for preclinical study. From: M. de Wild et al., Bone regeneration by the osteoconductivity of porous titanium implants manufactured by selective laser melting: A histological and µCT study in the rabbit, Tissue Engineering Part A, 19 (23-24):2645-54 (2013).

Modified surface of the 3D-printed implants. From: M. de Wild et al., Bone regeneration by the osteoconductivity of porous titanium implants manufactured by selective laser melting: A histological and µCT study in the rabbit, Tissue Engineering Part A, 19 (23-24):2645-54 (2013).

FEM simulation of open-porous scaffold. From: W. Hoffmann, S. Fabbri, R. Schumacher, S. Zimmermann, M. de Wild, FEM analysis of porous titanium bone scaffolds. European Cells and Materials, 26, Suppl. 4, 28 (2013). And winner of the Student Awards 2013 for the best poster presentation.

Influence of porosity and lattice angle.png

Influence of porosity and lattice angle on mechanic properties of the scaffold. From: S. Zimmermann, M. de Wild, Density- and Angle-Dependent Stiffness of Titanium 3D Lattice Structures, BioNanoMat 15 (S1), S35, (2014).

Referenzen

M. de Wild, C. Ghayor, S. Zimmermann, J. Rüegg, F. Nicholls, F. Schuler, T.-H. Chen, F.E. Weber, Osteoconductive Lattice Microarchitecture for Optimized Bone Regeneration, 3D Printing and Additive Manufacturing, doi.org/10.1089/3dp.2017.0129 6(1):40-49 (2019).
T.H. Chen, C. Ghayor, B. Siegenthaler, F. Schuler, J. Rüegg, M. de Wild, F.E. Weber, Lattice microarchitecture for bone tissue engineering from calcium-phosphate compared to titanium, Tissue Engineering Part A, 14 (19-20):1554-1561. doi: 10.1089/ten.TEA.2018.0014, (2018).
J. Rüegg, R. Schumacher, F.E. Weber, M. de Wild, Mechanical anisotropy of titanium scaffolds, Current Directions in Biomedical Engineering 3(2): 607–611 (2017).
M. de Wild, S. Zimmermann, J. Rüegg, R. Schumacher, T. Fleischmann, C. Ghayor, F.E. Weber, Influence of microarchitecture on osteoconduction and mechanics of porous titanium scaffolds generated by selective laser melting, J. 3D printing and additive manufacturing, 3(3): 142-151 (2016).
S. Zimmermann, F.E. Weber, R. Schumacher, J. Rüegg, M. de Wild, stiffness-anisotropy of porous implant geometries, European Cells and Materials, 29, Suppl. 2, 22 (2015).
L.S. Karfeld-Sulzer, C. Ghayor, B. Siegenthaler, M. de Wild, J.-C. Leroux, F.E. Weber, N-methyl Pyrrolidone/Bone Morphogenetic Protein-2 Double Delivery with In Situ Forming Implants, J. Contr Release, 203, 181-188 (2015).
F. E. Weber, M. de Wild, L. Karfeld-Sulzer, An Osteoconductive Titanium scaffold To Deliver BMP And Its Enhancer NMP, BioNanoMat 15 (S1), S59, DOI 10.1515/bnm-2014-9017 (2014).
M. de Wild, R. Schumacher, E. Schkommodau, F.E. Weber, In-Vivo Study of 3D Printed Open-Porous Ti implants. Poster at Annual Meeting 2014 of the Swiss Society of Biomedical Engineering, 27./28. Aug. 2014, ETHZ Zürich (Switzerland).
M. de Wild, R. Schumacher, K. Mayer, E. Schkommodau, D. Thoma, M. Bredell, A. Kruse, K.W. Grätz, F.E. Weber, Bone regeneration by the osteoconductivity of porous titanium implants manufactured by selective laser melting: A histological and µCT study in the rabbit, Tissue Engineering Part A, 19 (23-24):2645-54 (2013).