The tissue engineering focuses on synthesis or regeneration of tissues and organs. The hierarchical structure of nearly all
porous scaffolds on the macro, micro- and nanometer scales resembles that of engineering foams dedicated for technical
applications, but differ from the complex architecture of long bone. A major obstacle of scaffold architecture in tissue
regeneration is the limited cell infiltration as the result of the engineering approaches. The biological cells seeded on the
three-dimensional constructs are finally only located on the scaffold's periphery. This paper reports on the successful
realization of calcium phosphate scaffolds with an anatomical architecture similar to long bones. Two base materials,
namely nano-porous spray-dried hydroxyapatite hollow spheres and tri-calcium phosphate powder, were used to
manufacture cylindrically shaped, 3D-printed scaffolds with micro-passages and one central macro-canal following the
general architecture of long bones. The macro-canal is built for the surgical placement of nerves or larger blood vessels.
The micro-passages allow for cell migration and capillary formation through the entire scaffold. Finally, the nanoporosity
is essential for the molecule transport crucial for signaling, any cell nutrition and waste removal.
Rapid Prototyping and especially the 3D printing, allows generating complex porous ceramic scaffolds directly from powders. Furthermore, these technologies allow manufacturing patient-specific implants of centimeter size with an internal pore network to mimic bony structures including vascularization. Besides the biocompatibility properties of the base material, a high degree of open, interconnected porosity is crucial for the success of the synthetic bone graft. Pores with diameters between 100 and 500 μm are the prerequisite for vascularization to supply the cells with nutrients and oxygen, because simple diffusion transport is ineffective. The quantification of porosity on the macro-, micro-, and nanometer scale using well-established techniques such as Hg-porosimetry and electron microscopy is restricted. Alternatively, we have applied synchrotron-radiation-based micro computed tomography (SRμCT) to determine the porosity with high precision and to validate the macroscopic internal structure of the scaffold. We report on the difficulties in intensity-based segmentation for nanoporous materials but we also elucidate the power of SRμCT in the quantitative analysis of the pores at the different length scales.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.