Deformation analysis of gellan-gum based bone scaffold using on-the-fly tomography

Porous hydrogel-based structures reinforced by bioactive nano-particles allows one to design scaffolds with controlled stiffness, strength, and permeability for bone-tissue engineering applications. To be able to reliably assess the mechanical properties, it is necessary to study the material's deformation response on a volumetric basis and in high detail. In this paper, we present an investigation on the compressive characteristics of highly-relaxing gellan-gum bioactive-glass scaffold subjected to continuous uniaxial quasi-static compression. The sample was compressed with a loading rate of 0.4 mu m.s(-1) and simultaneously irradiated by X-rays during several micro-tomographical scans to obtain data for the evaluation of the deformation and strain fields using digital volume correlation (DVC). Such DVC evaluated on-the-fly micro-tomography was very challenging due to the low thickness of cell-walls and the material's intrinsic low attenuation of X-rays. Thus, we employed loading and tomographical devices equipped with a single-photon counting detector coupled with a DVC procedure, all developed in-house. From the acquired 34 tomographical scans, high-resolution voxel models with a resolution of 29.77 mu m were developed and subjected to DVC to obtain detailed deformation and strain fields of the material. It is shown that the presented method is suitable for the precise determination of the deformation response of the predominantly organic material developed as a biocompatible, bioresorbable bone scaffold. (C) 2017 The Authors. Published by Elsevier Ltd.