Biological Niches within Human Calcified Aortic Valves: Towards Understanding of the Pathological Biomineralization Process

Figure 6

Transmission electron microscopy (TEM) analyses of needle/rod-like pathological crystals. (a) Bright field (BF) image of a needle/rod-like nanocrystal collected from a calcified bicuspid aortic valve. In the bright field (BF) mode of the TEM, an aperture is placed in the back focal plane of the objective lens, which allows only the direct beam to pass. In this case, the image results from a weakening of the direct beam by its interaction with the sample. Therefore, mass thickness and diffraction contrast contribute to image formation: thick areas, in which heavy atoms are enriched, and crystalline areas appear with dark contrast. (b) EDS spectrum corresponding to the nanocrystal showed in panel (a). The spectrum clearly demonstrated the calcium phosphate nature of the nanocrystal. Ni and Cu belong to the 3 mm diameter Ni-Cu grid.

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