Micro- and nanostructure specific X-ray tomography reveals less matrix formation and altered collagen organization following reduced loading during Achilles tendon healing
Journal article, 2024

Recovery of the collagen structure following Achilles tendon rupture is poor, resulting in a high risk for re-ruptures. The loading environment during healing affects the mechanical properties of the tendon, but the relation between loading regime and healing outcome remains unclear. This is partially due to our limited understanding regarding the effects of loading on the micro- and nanostructure of the healing tissue. We addressed this through a combination of synchrotron phase-contrast X-ray microtomography and small-angle X-ray scattering tensor tomography (SASTT) to visualize the 3D organization of microscale fibers and nanoscale fibrils, respectively. The effect of in vivo loading on these structures was characterized in early healing of rat Achilles tendons by comparing full activity with immobilization. Unloading resulted in structural changes that can explain the reported impaired mechanical performance. In particular, unloading led to slower tissue regeneration and maturation, with less and more disorganized collagen, as well as an increased presence of adipose tissue. This study provides the first application of SASTT on soft musculoskeletal tissues and clearly demonstrates its potential to investigate a variety of other collagenous tissues. Statement of significance: Currently our understanding of the mechanobiological effects on the recovery of the structural hierarchical organization of injured Achilles tendons is limited. We provide insight into how loading affects the healing process by using a cutting-edge approach to for the first time characterize the 3D micro- and nanostructure of the regenerating collagen. We uncovered that, during early healing, unloading results in a delayed and more disorganized regeneration of both fibers (microscale) and fibrils (nanoscale), as well as increased presence of adipose tissue. The results set the ground for the development of further specialized protocols for tendon recovery.


3D organization

Phase-contrast microtomography

Small-angle X-ray scattering tensor tomography


Hierarchical tissue structure


Isabella Silva Barreto

Institutionen för Biomedicinsk Teknik

Maria Pierantoni

Institutionen för Biomedicinsk Teknik

Leonard Nielsen

Chalmers, Physics, Materials Physics

Malin Hammerman

Linköping University

Institutionen för Biomedicinsk Teknik

Ana Diaz

Paul Scherrer Institut

Vladimir Novak

Paul Scherrer Institut

Pernilla Eliasson

Sahlgrenska University Hospital

Linköping University

Marianne Liebi

Chalmers, Physics, Materials Physics

Swiss Federal Institute of Technology in Lausanne (EPFL)

Paul Scherrer Institut

Hanna Isaksson

Institutionen för Biomedicinsk Teknik

Acta Biomaterialia

1742-7061 (ISSN) 18787568 (eISSN)

Vol. 174 245 257-

Subject Categories

Biomaterials Science





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