Purpose:
To image the ultrastructure of the intact, anterior primate lens capsule using Atomic Force Microscopy (AFM).
Methods:
A commercial Asylum AFM was used to image the collagen structure of two fully hydrated lens capsules at the nanoscale level. Lenses obtained from a human cadaver (45 y/o, 10 days postmortem) and a cynomologus monkey (10.4 y/o, 17 days postmortem) were used for these experiments. Prior to imaging, a portion of the anterior lens capsule approximately 5mm in diameter was removed from the lens by means of a continuous curvilinear capsulorhexis technique, placed on a petri dish, and transported to the Asylum AFM. The images were obtained in contact mode, in which the cantilever tip is kept in continuous contact with the sample surface, maintaining constant cantilever deflection while scanning. The piezoelectric mechanism applies vertical position corrections to keep this deflection constant, thereby mapping the actual three-dimensional topography of the sample surface.
Results:
AFM was successful in providing high resolution images of the nano-structure of the primate lens capsule (Figure 1). The images demonstrated an interwoven beehive structure of the capsule collagen.
Conclusions:
AFM can provide high-resolution, quantitative images of intact, hydrated lens capsules.
Figure1. Resulting AFM images. Height images of (A) human cadaveric and (B) non-human primate lens capsules.
Keywords: topography • cataract • accommodation