NON-DESTRUCTIVE CHARACTERIZATION OF PRINTED HYDROGEL SCAFFOLDS USING SYNCHROTRON-BASED IMAGING
Date
2020-08-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Thesis
Degree Level
Masters
Abstract
Hydrogel scaffolds have shown great promise as main components in the artificial tissue-engineered scaffolds for the repair of injured tissues. The fabrication of hydrogel scaffolds with precise geometry can be achieved by three-dimension (3D) printing (also known as additive manufacturing) technology. One of the key requirements in 3D printing of hydrogels is to achieve high fidelity or printability to fabricate the scaffolds that can resemble the designed structure. For the printability characterization, non-destructive visualization of 3D printed scaffolds is essentially needed. Also, the 3D printed scaffolds, when implanted in vivo, need to be visualized for tracking their success, which may include the scaffold status such as mechanical deformation and formation of new tissues. Hence, 3D visualization of the hydrogel scaffold structure is vital to characterize the printability and scaffold status. Unfortunately, conventional imaging techniques in tissue engineering are impossible to non-destructively visualize the whole 3D structure of hydrogel scaffolds due to the limited imaging capability. To address these issues mentioned, the aim of this research is to 1) study synchrotron propagation-based imaging technique with computed tomography (SR-PBI-CT) imaging parameters to visualize the printed scaffolds non-destructively, 2) 3D print the gelatin methacrylate (GelMA) hydrogel scaffolds, and non-destructively characterize the printed scaffolds printability and mechanical deformation using the optimal SR-PBI-CT imaging method.
The SR-PBI-CT imaging parameters were examined using a standard sample alginate scaffold and found optimal Sample to Detector Distance (SDD), X-ray energy, and the number of projections to visualize printed hydrogel scaffolds. Upon finding optimal SR-PBI-CT imaging parameters, the characterization of printability and mechanical deformation of printed GelMA scaffolds was conducted based on the imaging results. The hydrogels were clearly visualized and characterized from the phase-retrieved reconstructed slices. From the phase-retrieved reconstructed slices, the printability results show the best printing speed for printing GelMA scaffolds, and the compression study shows the strength and status of the printed scaffold under different levels of deformation. The results of the printability and mechanical deformation characterization can be used to improve the design and fabrication of GelMA scaffolds. This study illustrates that SR-PBI-CT is feasible for non-destructive visualization of the hydrogel scaffolds as well as the quantification of their structures.
iii
The contribution of this research also rests on determining the optimal imaging setup or parameters for hydrogel scanning using SR-PBI-CT. Also, this research illustrates it is feasible to lower the X-ray dose during the imaging by reducing the number of projections from 1800 to 450, thus reducing the radiation exposure by 75% to the imaged samples. This would represent a significant step towards the application of the SR-PBI-CT to visualize hydrogel scaffolds implanted in living animal models and eventually to human patients.
Description
Keywords
Hygrogel scaffolds, tissue engineering, synchrotron imaging, non-destructive, visualization
Citation
Degree
Master of Science (M.Sc.)
Department
Biomedical Engineering
Program
Biomedical Engineering