Maria Pierantoni (1), Isabella Silva Barreto (1), Malin Hammerman (1,2), Lissa Verhoeven (1), Elin Törnquist (1), Vladimir Novak (3), Rajmund Mokso (3,4), Pernilla Eliasson (2), Hanna Isaksson (1)
Scientific Reports, 11, Issue 17313, August 2021. DOI: 10.1038/s41598-021-96589-w

Keywords

Tendons; X-ray tomography

Abstract

Achilles tendons are mechanosensitive, and their complex hierarchical structure is in part the result of the mechanical stimulation conveyed by the muscles. To fully understand how their microstructure responds to mechanical loading a non-invasive approach for 3D high resolution imaging suitable for soft tissue is required. Here we propose a protocol that can capture the complex 3D organization of the Achilles tendon microstructure, using phase-contrast enhanced synchrotron micro-tomography (SR-PhC-μCT). We investigate the effects that sample preparation and imaging conditions have on the resulting image quality, by considering four types of sample preparations and two imaging setups (sub-micrometric and micrometric final pixel sizes). The image quality is assessed using four quantitative parameters. The results show that for studying tendon collagen fibers, conventional invasive sample preparations such as fixation and embedding are not necessary or advantageous. Instead, fresh frozen samples result in high-quality images that capture the complex 3D organization of tendon fibers in conditions as close as possible to natural. The comprehensive nature of this innovative study by SR-PhC-μCT breaks ground for future studies of soft complex biological tissue in 3D with high resolution in close to natural conditions, which could be further used for in situ characterization of how soft tissue responds to mechanical stimuli on a microscopic level.

How Our Software Was Used

Dragonfly was used to perform 3D rendering and to create videos.

Author Affiliation

(1) Department of Biomedical Engineering, Lund University, Box 118, 221 00 Lund, Sweden.
(2) Department of Biomedical and Clinical Sciences, Linköping University, 581 83 Linköping, Sweden.
(3) Swiss Light Source, Paul Scherrer Institute, 5232Villigen, Switzerland.
(4) Division of Solid Mechanics, Lund University, Box 118, 221 00 Lund, Sweden.