Nondestructive micro-computed tomography for biological imaging and quantification of scaffold–bone interaction in vivo

Scaffolds, also called bioscaffolds, are needed in all tissue engineering applications as carriers for cells and biochemical factors, as constructs providing appropriate mechanical conditions, or as a combination of the two. The aim of this paper is to present recent developments in micro-computed tomography (μCT) analyses of scaffolds. The focus will be on imaging and quantification aspects in bone research, and will deal with the assessment of scaffold architecture and how it interacts with bone tissue. We show that micro-architectural imaging is a nondestructive and noninvasive procedure that allows a precise three-dimensional (3D) measurement of scaffold architecture. Direct μCT-based image analysis allows to accurately quantify scaffold porosity, surface area, and 3D measures such as pore size, pore distribution, and strut thickness; furthermore, it allows for a precise measurement of bone growth into the scaffold and onto its surface. This methodology is useful for quality control of scaffold fabrication processes, to assess scaffold degradation kinetics, and to assess bone tissue response. Even more so, in combination with bioreactors or in vivo animal models, μCT allows to qualitatively and quantitatively assess the spatial and temporal mineralization of bone tissue formation in scaffolds; such longitudinal studies improve the assessment of bone response due to scaffold architecture. Computational models will be helpful in further analyses of these data in order to improve our understanding of mechanical and biochemical stimuli on bone formation, and are likely to provide valuable knowledge to optimize scaffold design.