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Abstract Characterization of bone quality during the healing process is crucial for successful implantation procedures and patient comfort. In this study, a bone implant specimen that underwent a 4-week healing period was investigated. Bimodal atomic force microscopy (AFM) was employed to simultaneously obtain the morphology and elastic modulus maps of the newly formed and pre-existing bone regions within the sample. Results indicate that the new bone matrix possessed lower mineralization levels and presented larger, uneven mineral grains, exhibiting the attributes of a woven bone. On the other hand, the old bone matrix exhibited a more uniform and mineralized structure, which is characteristic of lamellar bones. The new bone had a lower overall elastic modulus than the old bone. Bimodal AFM further confirmed that the new bone displayed three regions comprising unmineralized, partially mineralized, and fully matured sections, which indicate a turbulent change in its composition. Meanwhile, the old bone exhibited two sections comprising partially mineralized and matured bone parts, which denote the final phase of mineralization. This study provides valuable insights into the morphological and nanomechanical differences between the old and new bone matrixes and presents a novel approach to investigate bone quality at different phases of the bone-healing process.
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Evaluation of bone formation on orthopedic implant surfaces using an ex-vivo bone bioreactor system
Abstract Recent advances in materials and manufacturing processes have allowed the fabrication of intricate implant surfaces to facilitate bony attachment. However, refinement and evaluation of these new design strategies are hindered by the cost and complications of animal studies, particularly during early iterations in the development process. To address this problem, we have previously constructed and validated an ex-vivo bone bioreactor culture system that can maintain the viability of bone samples for an extended period ex-vivo. In this study, we investigated the mineralization of a titanium wire mesh scaffold under both static and dynamic culturing using our ex vivo bioreactor system. Thirty-six cancellous bone cores were harvested from bovine metatarsals at the time of slaughter and divided into five groups under the following conditions: Group 1) Isolated bone cores placed in static culture, Group 2) Unloaded bone cores placed in static culture in contact with a fiber-mesh metallic scaffold, Group 3) Bone cores placed in contact with a fiber-mesh metallic scaffold under the constant pressure of 150 kPa, Group 4) Bone core placed in contact with a fiber-mesh metallic scaffold and exposed to cyclic loading with continuous perfusion flow of media within the ex-vivo culture system and Group 5) Bone core evaluated on Day 0 to serve as a positive control for comparison with all other groups at weeks 4 and 7. Bone samples within Groups 1–4 were incubated for 4 and 7 weeks and then evaluated using histological examination (H&E) and the Live-Dead assay (Life Technologies). Matrix deposits on the metallic scaffolds were examined with scanning electron microscopy (SEM), while the chemical composition of the matrix was measured using energy-dispersive x-ray spectroscopy (EDX). We found that the viability of bone cores was maintained after seven weeks of loading in our ex vivo system. In addition, SEM images revealed crystallite-like structures on the dynamically loaded metal coupons (Group 4), corresponding to the initial stages of mineralization. EDX results further confirmed the presence of carbon at the interface and calcium phosphates in the matrix. We conclude that a bone bioreactor can be used as an alternate tool for in-vivo bone ingrowth studies of new implant surfaces or coatings.
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- PAR ID:
- 10311868
- Date Published:
- Journal Name:
- Scientific Reports
- Volume:
- 11
- Issue:
- 1
- ISSN:
- 2045-2322
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1038/s41598-021-02070-z
