ATOMIC-FORCE MICROSCOPIC STUDIES OF ISOLATED COLLAGEN FIBRILS OF THE BOVINE CORNEA AND SCLERA

Isolated collagen fibrils from the bovine cornea and sclera were inves tigated by atomic force microscopy (AFM) in a non-contact mode. AFM im aging visualized the surface topography of both corneal and scleral co llagen fibrils with quantitative information on their height and width . The corneal collagen fibrils had a height of 15.6+/-1.5 nm and a D-p eriodicity of 63.9+/-0.5 nm. On the other hand, the height and D-perio dicity of scleral collagen fibrils were 74.2+/-55.7 nm and 65.4+/-0.7 nm, respectively. A periodic banding pattern of grooves and ridges was found in individual fibrils, although the groove depth was 2.81+/-0.2 9 nm in the cornea and 5.47+/-0.66 nm in the sclera, When collagen fib rils were treated with acetic acid, they swelled and untwisted into su bfibrils. The AFM is useful to analyze surface morphology of collagen fibrils and their subfibrils at high resolution with quantitative info rmation.