3D nanoscale analysis of bone healing around degrading Mg implants evaluated by X-ray scattering tensor tomography
Journal article, 2021

The nanostructural adaptation of bone is crucial for its biocompatibility with orthopedic implants. The bone nanostructure also determines its mechanical properties and performance. However, the bone's temporal and spatial nanoadaptation around degrading implants remains largely unknown. Here, we present insights into this important bone adaptation by applying scanning electron microscopy, elemental analysis, and small-angle X-ray scattering tensor tomography (SASTT). We extend the novel SASTT reconstruction method and provide a 3D scattering reciprocal space map per voxel of the sample's volume. From this reconstruction, parameters such as the thickness of the bone mineral particles are quantified, which provide additional information on nanostructural adaptation of bone during healing. We selected a rat femoral bone and a degrading ZX10 magnesium implant as model system, and investigated it over the course of 18 months, using a sham as control. We observe that the bone's nanostructural adaptation starts with an initially fast interfacial bone growth close to the implant, which spreads by a re-orientation of the nanostructure in the bone volume around the implant, and is consolidated in the later degradation stages. These observations reveal the complex bulk bone-implant interactions and enable future research on the related biomechanical bone responses. Statement of significance: Traumatic bone injuries are among the most frequent causes of surgical treatment, and often require the placement of an implant. The ideal implant supports and induces bone formation, while being mechanically and chemically adapted to the bone structure, ensuring a gradual load transfer. While magnesium implants fulfill these requirements, the nanostructural changes during bone healing and implant degradation remain not completely elucidated. Here, we unveil these processes in rat femoral bones with ZX10 magnesium implants and show different stages of bone healing in such a model system.

Tomography

X-ray scattering

Biomineralization

Degradable magnesium implants

Implant degradation

Author

Marianne Liebi

Swiss Federal Laboratories for Materials Science and Technology (Empa)

Chalmers, Physics, Materials Physics

Paul Scherrer Institut

Viviane Lutz-Bueno

Paul Scherrer Institut

Manuel Guizar-Sicairos

Paul Scherrer Institut

Bernd M. Schönbauer

University of Natural Resources and Life Sciences

Johannes Eichler

Medical University of Graz

Elisabeth Martinelli

Medical University of Graz

Jörg F. Löffler

Swiss Federal Institute of Technology in Zürich (ETH)

Annelie Weinberg

Medical University of Graz

Helga Lichtenegger

University of Natural Resources and Life Sciences

Tilman A. Grünewald

European Synchrotron Radiation Facility (ESRF)

Acta Biomaterialia

1742-7061 (ISSN)

Vol. In Press

Subject Categories

Bio Materials

Biomaterials Science

Medical Materials

DOI

10.1016/j.actbio.2021.07.060

More information

Latest update

8/26/2021