Permeability and mechanical properties of triply periodic minimal surface scaffolds for bone regeneration

Permeability and mechanical properties of triply periodic minimal surface scaffolds for bone regeneration

Bobbert, F.S.L.

Zadpoor, A.A. (mentor)

Mechanical, Maritime and Materials Engineering

Biomedical engineering

Tissue biomechanics and implants

2016-02-11

Scaffolds for bone regeneration have been investigated as bone substitutes in critical sized bone defects. It is known that the architecture of these scaffolds is important for the bone regeneration process, which depends on cell response and vascular ingrowth into the scaffold. With advanced fabrication techniques, such as selective laser melting, it is possible to manufacture complex geometries. In this study, Ti6Al4V scaffolds based on four different minimal surfaces, primitive, I-WP, gyroid and diamond, with different porosities were evaluated. Of these scaffolds, the morphological and mechanical properties, and the permeability were determined with micro-CT, static compression tests and fatigue tests, and permeability experiments and computational fluid dynamic simulations. Porosities of 71.3-49.2%, 65-44.3%, 65.6-52% and 59.7-44.2% were found for the primitive, I-WP, gyroid and diamond scaffolds, respectively. It was observed that the permeability depends on the shape of the unit cell as well as on the apparent density of the scaffold. Permeability values of 5.48 10-11-6.10 10-9m2 and 1.29-6.96 10-9m2 were obtained from the laminar experimental and computational approaches, respectively. The static compression tests showed that the mechanical properties, such as the plateau stress, quasi-elastic gradient, plateau end stress, and the yield strength depend on the type of unit cell and the porosity. The lowest fatigue lives were found for the primitive unit cells, while the I-WP scaffolds and the diamond scaffolds with the lowest and highest apparent density, respectively, were still intact after 106 cycles. The results in this study suggest that some of the scaffolds evaluated would be suitable as scaffolds for bone regeneration.

bone regeneration

http://resolver.tudelft.nl/uuid:af0df733-9bfe-4c74-8032-7714d23127dd

2017-02-11

Student theses

master thesis

(c) 2016 Bobbert, F.S.L.