The mantis shrimp eye imaged in 3D using 4th generation synchrotron multiscale phase contrast tomography.

The stomatopod eye is a fascinating biological system capable of detecting both colour and polarization of light, making it a highly complex, mixed-tissue sample. In the investigation of complex biological systems, three-dimensional methods spanning multiple length scales with the power to resolve soft tissues are required. In this study, propagation-based phase contrast X-ray computed tomography with stitching at a 4th generation synchrotron was used to image a full stomatopod eye with sub-micron voxel size to illustrate how this method accommodates these demands. The images are based on natural X-ray contrast and without any added labels or staining agents. Key features of the eye were identified and segmented. Utilizing these segmentations, photo filter volumes, chitin porosity volumes, and muscle fiber periodicities were measured, demonstrating the ability to perform quantitative as well as qualitative investigations. Neural compartments and associated cells were discernable, showing the power of 4th generation synchrotron phase contrast for the study of soft tissues. The illustrated properties along with its non-invasive nature proves phase contrast synchrotron X-ray computed tomography with stitching to be a powerful tool for the investigation of biological materials.