Journal of Electron Microscopy Advance Access originally published online on February 13, 2009
Journal of Electron Microscopy 2009 58(2):47-53; doi:10.1093/jmicro/dfp005
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Visualization of the ultrastructural interface of cells with the outer and inner-surface of coral skeletons
1 Department of Life Sciences
2 National Institute for Biotechnology in the Negev
3 Department of Biotechnology Engineering, Ben-Gurion University of the Negev, Beer Sheva 84105
4 Ariel University Center of Samaria, Ariel 44837, Israel
* To whom correspondence should be addressed. E-mail: dbaranes{at}bgu.ac.il
Crystalline, porous biomaterials, such as marine invertebrate skeletons, have been widely used for functional reconstruction of human tissues like bone and dental implants. Since in such an abrasive microenvironment adequate cell–material interactions are crucial for a successful treatment, it is of great importance to improve the means to examine these interactions. We developed a method that reveals the ultrastructure of the interface between coral skeletons and cultured neural cells to a higher quality than do traditional methods as it does not include damaging procedures like decalcification or sectioning non-decalcified skeletons. It is rather based on generating two electron opacity distinct Araldite masks, of the skeleton and its surrounding, by polymerizing them to different durations. The contrast created at the border of the two masks outlined the fine and fragile crystals of the coral skeleton's outer and inner surfaces and their contact sites with the cells. The skeleton's internal structure contains a mesh of narrow (few microns wide) and large channel-shaped gaps interrupted by irregular-shaped crystalline material. Neural cells grew on the skeleton surface by stretching between crystal tips, with occasional rearrangements of cytoskeletal fibers located near the anchorage focal adherence points. Cell processes infiltrated the skeleton interior by stretching between inter-surface crystals and by adjusting their volume to the space of the conduits they grew into. The technique advances the study of coral biology and of neural cells–hard biomaterial interaction; it can be applied to other biomaterials and cell types and open new ways for studying tissue development and engineering.
Keywords transmission electron microscopy, electron opacity, carbonate skeleton, coral, neurons, cell–material interface
Received 1 October 2008, accepted 16 January 2009