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Ethanol and formaldehyde fixation irreversibly alter bones' organic matrix
Niels Hammer1, Christian Voigt, Michael Werner
1Institute of Anatomy, University of Leipzig, Faculty of Medicine, Liebigstraße 13, 04103 Leipzig, Germany.
Journal of the Mechanical Behavior of Biomedical Materials
|October 15, 2013
Summary
Ethanol and formaldehyde fixation irreversibly alter bone material properties, especially the organic matrix. These changes impact bone anisotropy, making fixation unsuitable for studies requiring vital bone characteristics.
Area of Science:
- Biomedical Engineering
- Orthopedics
- Materials Science
Background:
- Biomechanical testing of bone often uses fixed tissues, but the impact of ethanol and formaldehyde fixation on bone material properties is debated.
- Previous studies have controversial findings regarding the appropriateness of these fixation methods for clinical and biomechanical research.
Purpose of the Study:
- To investigate the irreversible changes in bone material properties caused by ethanol and formaldehyde fixation.
- To determine if these alterations are primarily related to the bone's organic matrix.
Main Methods:
- Three-dimensional laser vibrometry-based modal analysis was used on human coxal bones (fresh and macerated).
- Specimens underwent ethanol or formaldehyde fixation, with changes in weight, modal frequencies, and anisotropy (using Modal Assurance Criterion - MAC) recorded.
Main Results:
- Fixation irreversibly altered modal frequencies and bone anisotropy in unfixed specimens.
- Ethanol fixation led to weight loss, while formaldehyde caused structural changes in unfixed bones.
- In macerated bones (inorganic controls), fixation-induced changes were reversible upon rinsing.
Conclusions:
- Ethanol and formaldehyde fixation irreversibly alter unfixed bone's material properties and anisotropy due to changes in the organic matrix.
- Fixation effects were reversible in macerated bones, highlighting the role of the organic component.
- These fixation methods are not recommended when material properties close to the vital state are required; modal analysis can reveal the organic matrix's influence.
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