Computed Tomography as a Characterization Tool for Engineered Scaffolds with Biomedical Applications

Abstract

The ever-growing field of materials with applications in the biomedical field holds great promise regarding the design and fabrication of devices with specific characteristics, especially scaffolds with personalized geometry and architecture. The continuous technological development pushes the limits of innovation in obtaining adequate scaffolds and establishing their characteristics and performance. To this end, computed tomography (CT) proved to be a reliable, nondestructive, high-performance machine, enabling visualization and structure analysis at submicronic resolutions. CT allows both qualitative and quantitative data of the 3D model, offering an overall image of its specific architectural features and reliable numerical data for rigorous analyses. The precise engineering of scaffolds consists in the fabrication of objects with well-defined morphometric parameters (e.g., shape, porosity, wall thickness) and in their performance validation through thorough control over their behavior (in situ visualization, degradation, new tissue formation, wear, etc.). This review is focused on the use of CT in biomaterial science with the aim of qualitatively and quantitatively assessing the scaffolds’ features and monitoring their behavior following in vivo or in vitro experiments. Furthermore, the paper presents the benefits and limitations regarding the employment of this technique when engineering materials with applications in the biomedical field.

Development of Conjugated Kefiran-Chondroitin Sulphate Cryogels with Enhanced Properties for Biomedical Applications

“…Morphological properties of scaffolds refer to their physical characteristics, such as shape, size, and surface structure. These properties can significantly impact the scaffold’s ability to support tissue growth and repair, and must be carefully designed and optimized to match the specific requirements of the intended application [ 41 ].…”

“…SEM imaging and Micro-CT ( Figure 5 ), as imaging techniques, are commonly used to evaluate the scaffold’s microstructure by providing high-resolution two-dimensional images of the surface of specimens down to the nanometer scale [ 41 ]. Thus, the SEM investigation of freeze-dried kefiran-CS cryogels showed lightweight, porous materials with a sponge-like structure that were created during, and subsequent to, freeze-drying ( Figure 5 B).…”

Modified Histopathological Protocol for Poly-ɛ-Caprolactone Scaffolds Preserving Their Trabecular, Honeycomb-like Structure

“…Despite the considerable developments in imaging techniques allowing for comprehensive in vivo and postmortem scaffold evaluation, and even the creation of 3D virtual models [ 29 , 30 ], little attention has been paid to the refinement and updating of histopathological techniques, which remain the basic tool for assessments of scaffold morphology, biocompatibility, and interactions with the surrounding cells. The standard techniques used today only allow for evaluations of selected representative fragments, where the scaffold is often cleared, melted, or swollen, and it is not possible to obtain the full cross-section view with the preserved scaffold’s honeycomb-like structure [ 31 , 32 ].…”

A Beginner’s Guide to the Characterization of Hydrogel Microarchitecture for Cellular Applications

“…In the µ-CT equipment, the sample is placed on a rotational stage and exposed to an X-ray source, and the passing light is captured by an X-ray detector. The passing X-rays can be attenuated (i.e., absorbed or scattered) by the sample thickness, density, and composition, providing phase contrast to the structures and components [ 111 ]. The µ-CT images can be reconstructed in 3D with an up to 1 μm voxel (3D pixel) resolution, making this a high-resolution technique.…”

“…Other limitations include vibrations in the µ-CT’s rotatory stage, which can cause motion artefacts by displacing the sample if it is not properly fixed—a common challenge with wet materials [ 123 ]. Information on the in-depth specifications and further limitations of µ-CT in materials research can be found elsewhere [ 111 , 123 ].…”