Multiscale Mineralization in the Leopard Gecko Eggshell

Researchers from McGill University have published a study outlining new ultrastructural details within the eggshell of the common leopard gecko. Using advanced imaging techniques, they reveal the intertwined composite structure of calcium carbonate mineral and organic fibers. Within the gecko eggshell, the authors highlight the mineral's sensitivity to aqueous environments and the importance of cryogenic methods for accurate structure and compositional preservation. They describe heretofore unknown nano- and microscale details of mineral motifs that include mineralized nodular scutes, rosettes, and corollas, whose function may relate to the eggshell's evolutionary adaptation for protection and embryonic development. These hierarchical and multiscale arrangements between organic fibers and mineral formations contribute to the mechanical properties of the eggshell. They also provide insight into biomineralization processes and potential applications in materials science.

According to corresponding author Prof. Marc D. McKee, “Dragonfly 3D World has become an essential tool in our 3D imaging workflow for structural biology in the biomineralization field.  We use the Deep Learning Tool extensively to process data from X-ray microscopy (XRM) and focused ion beam – scanning electron microscopy (FIB-SEM) volumes.  The use of multi-ROIs, watershed transform, and thickness mapping tools have greatly simplified our quantitative assessment of complex features in the eggshell.”

Video Presentation

Publication

Deering, J., Nelea, V., and McKee, M.D. (2024). Multiscale mineralization in the leopard gecko eggshell. Advanced Functional Materials, 34(24). https://doi.org/10.1002/adfm.202316422

Research Center

McGill University, Faculty of Dental Medicine and Oral Health Sciences (https://www.mcgill.ca/dentistry/)

McGill University, Department of Anatomy and Cell Biology (https://www.mcgill.ca/anatomy/)

McGill University, Faculty of Medicine and Health Sciences (https://www.mcgill.ca/medhealthsci/)

Keywords: Leopard Gecko, Eggshell Biomineralization, Collagen-based Materials, Reptilian Eggshell, X-Ray Microscopy

X-ray microscopy reconstruction of an intact, fertilized leopard gecko egg after 50 days of incubation. The embryo is in an advanced stage of skeletal development as it nears hatching.
(Left/top) Nodular mineral scutes are sporadically patterned across the exterior portion of some gecko eggshells. (Right/bottom) Larger mineral rosettes are more sparsely distributed across the eggshell in some gecko eggs.
Thickness map of a scute-containing gecko eggshell fragment.
Segmentation of a FIB-SEM volume across the full eggshell thickness showing interconnected scutes and the underlying fiber network. Using 2.5D deep learning models can help segment features through charging artifacts.