X-ray phase contrast imaging of soft biomaterials in a whole-animal model

Statement of Purpose: Imaging soft biomaterials in vivo is a challenge as most conventional techniques fall short in resolution, penetration depth, or acquisition time. Also, many techniques require additional contrast agents to visualize biomaterials, which have risks associated with their use. Having the capability to observe whole biomaterial constructs while they are still implanted without introducing exogenous contrast would improve the process of developing them for clinical use. Monitoring material properties such as degradation, stability, interaction with surrounding tissue, and point of failure in real time would allow for more relevant information gathering and remove potential sources of error due to processing the tissue after sacrifice. Conventional x-ray imaging allows fast, high-resolution imaging at high penetration depth. However, the low absorption of soft biomaterials and surrounding tissue limits contrast in x-ray-based imaging methods. Previous studies have shown that techniques based on x-ray phase contrast (XPC) may enable imaging soft biomaterials invivo without contrast agents. Previous studies employing XPC used a synchrotron source for high-energy x-rays, resulting in useful images, but this is not practical for widespread use¹. The purpose of this paper is to evaluate the capability of imaging soft biomaterials through XPC tomography in a small animal model using a commercially available, in-lab liquid metal jet source.