[Observation of human corneal and scleral collagen fibrils by atomic force microscopy]

We attempted to analyze the three-dimensional ultrastructure of human corneal and scleral collagen fibrils with an atomic force microscope (AFM).

A normal eye removed from a 66-year-old male was used in the study. Suspended corneal and scleral collagen fibrils were individually attached to glass slides by centrifugation. These collagen fibrils were air-dried and observed with a non-contact mode AFM in air.

AFM imaging provided information on the surface topography of both corneal and scleral collagen fibrils. The corneal collagen fibrils had a height of 11.9 +/- 1.0 (mean +/- standard deviation) nm and the scleral fibrils of 82.5 +/- 35.6 nm. A periodic banding pattern of grooves and ridges was clearly found in both types of fibrils; the D-periodicity and the groove depth were 65.7 +/- 0.8 nm and 1.46 +/- 0.50 nm in the corneal fibrils, and 67.3 +/- 1.1 nm and 6.16 +/- 1.23 nm in the scleral fibrils.

Surface topographic images of human corneal and scleral collagen fibrils were clearly obtained with the AFM. This technique provides quantitative information on the surface morphology of the collagen fibrils at high resolution.