A Standardised Approach to the Biomechanical Evaluation of Tracheal Grafts

Abstract

The ideal tracheal substitute must have biomechanical properties comparable to the native trachea, but currently there is no standardised approach to evaluating these properties. Here we propose a novel method for evaluating and comparing the properties of tracheal substitutes, thus systematising both measurement and data curation. This system was tested by comparing native rabbit tracheas to frozen and decellularised specimens and determining the histological characteristics of those specimens. We performed radial compression tests on the anteroposterior tracheal axis and longitudinal axial tensile tests with the specimens anastomosed to the jaw connected to a measuring system. All calculations and results were adjusted according to tracheal size, always using variables relative to the tracheal dimensions, thus permitting comparison of different sized organs. The biomechanical properties of the decellularised specimens were only slightly reduced compared to controls and significant in regard to the maximum stress withstood in the longitudinal axis (−0.246 MPa CI [−0.248, −0.145] MPa) and the energy stored per volume unit (−0.124 mJ·mm−3 CI [−0.195, −0.055] mJ·mm−3). The proposed method is suitable for the systematic characterisation of the biomechanical properties of different tracheal substitutes, regardless of the size or nature of the substitute, thus allowing for direct comparisons.

Assessing the 3D Printability of an Elastomeric Poly(caprolactone-co-lactide) Copolymer as a Potential Material for 3D Printing Tracheal Scaffolds

“…The higher ratios PLCL91 and PLCL82 represent a typical glassy behavior with immediate failure after the yield point with higher crystallinity as evidenced from the DSC thermograms, whereas PLCL65 and PLCL73, due to their increased caprolactone content, showed an elastic behavior with an elongation at break of 200.47 ± 9 and 99.8 ± 2% and tensile strength of 63.4 ± 3 and 112.5 ± 7, respectively, showing that the synthesized material is mechanically superior to the native rabbit trachea. 21 Since the higher ratios were brittle and less elastic, PLCL65 and PLCL73 were chosen for our further 3D printing studies.…”

The Growing Medical Need for Tracheal Replacement: Reconstructive Strategies Should Overcome Their Limits

“…Indeed, several in vivo preclinical studies have been carried out to evaluate biochemical properties of decellularized ( Zhao et al, 2016 ), synthetic ( Dharmadhikari et al, 2019 ) or scaffold-free constructs ( Machino et al, 2019 ). However, since the first requirement for an adequate tracheal substitute is to mimic the tracheal’s native biomechanical properties, the definition of standard approaches and biomechanical tests would be extremely helpful to obtain comparable results among different studies and further improve this field ( Martínez-Hernández et al, 2021 ).…”

A facile 3D bio‐fabrication of customized tubular scaffolds using solvent‐based extrusion printing for tissue‐engineered tracheal grafts

“…In past research work, a few reports reported systematic mechanical investigations of the native trachea. 46,47 To our knowledge, only one report attempted to address the traction test of the native trachea. 47 However, the test was performed by pulling the sutured trachea till the breakpoint, but not directly measuring the traction force due to the sliding action of the tracheal scaffold and esophagus.…”

“…46,47 To our knowledge, only one report attempted to address the traction test of the native trachea. 47 However, the test was performed by pulling the sutured trachea till the breakpoint, but not directly measuring the traction force due to the sliding action of the tracheal scaffold and esophagus. In this regard, the present investigation could provide insight quantitatively the traction force generated during the sliding motion of the two components.…”

“…From the present study, spiral‐shaped scaffolds could be one of the suitably patterned grafts in the development of flexible tracheal scaffolds. In past research work, a few reports reported systematic mechanical investigations of the native trachea 46,47 . To our knowledge, only one report attempted to address the traction test of the native trachea 47 .…”