Bones are bio-composites with biologically tunable mechanical properties, where a polymer matrix of nanofibrillar collagen is reinforced by apatite mineral crystals. Some bones, such as antler, form and change rapidly, while other bone tissues, such as human tooth dentine, develop slowly and maintain constant composition and architecture for entire lifetimes. When studying apatite mineral microarchitecture, mineral distributions or mineralization activity of bone-forming cells, representative samples of tissue are best studied at submicrometre resolution while minimizing sample-preparation damage. Here, we demonstrate the power of ptychographic X-ray tomography to map variations in the mineral content distribution in three dimensions and at the nanometre scale. Using this non-destructive method, we observe nanostructures surrounding hollow tracts that exist in human dentine forming dentinal tubules. We reveal unprecedented quantitative details of the ultrastructure clearly revealing the spatially varying mineralization density. Such information is essential for understanding a variety of natural and therapeutic effects for example in bone tissue healing and ageing.

The complexity of lung diseases makes pre-clinical in vivo respiratory research in mouse lungs of great importance for a better understanding of physiology and therapeutic effects. Synchrotron-based imaging has been successfully applied to lung research studies, however longitudinal studies can be difficult to perform due to limited facility access. Laboratory-based x-ray sources, such as inverse Compton x-ray sources, remove this access limitation and open up new possibilities for pre-clinical small-animal lung research at high spatial and temporal resolution. The in vivo visualization of drug deposition in mouse lungs is of interest, particularly in longitudinal research, because the therapeutic outcome is not only dependent on the delivered dose of the drug, but also on the spatial distribution of the drug. An additional advantage of this approach, when compared to other imaging techniques, is that anatomic and dynamic information is collected simultaneously. Here we report the use of dynamic x-ray phase-contrast imaging to observe pulmonary drug delivery via liquid instillation, and by inhalation of micro-droplets. Different liquid volumes (4 l  , 20 l  , 50 l ) were tested and a range of localized and global distributions were observed with a temporal resolution of up to 1.5 fps. The in vivo imaging results were confirmed by ex vivo x-ray and fluorescence imaging. This ability to visualize pulmonary substance deposition in live small animals has provided a better understanding of the two key methods of delivery; instillation and nebulization.

We describe the first dynamic and the first in vivo X-ray imaging studies successfully performed at a laser-undulator-based compact synchrotron light source. The X-ray properties of this source enable time-sequence propagation-based X-ray phase-contrast imaging. We focus here on non-invasive imaging for respiratory treatment development and physiological understanding. In small animals, we capture the regional delivery of respiratory treatment, and two measures of respiratory health that can reveal the effectiveness of a treatment; lung motion and mucociliary clearance. The results demonstrate the ability of this set-up to perform laboratory-based dynamic imaging, specifically in small animal models, and with the possibility of longitudinal studies.

The imaging of live animals at a synchrotron source presents challenges in terms of remote monitoring and intervention, in addition to a sample that is changing and moving with time. This work describes experimental techniques that have been developed to address these challenges and capture image sequences that can equip a range of biomedical studies.