Type I collagen with proteoglycans

Transmission electron micrograph showing collagen fibrils in the human sclera. This sample has been treated with a cationic dye to reveal dermatan/chondroitin sulphate proteoglycans attached to type I collagen fibrils. These proeteoglycans are visible as the small projections along the sides of the larger collagen fibrils. The a-e repeat periodic banding pattern is also clearly seen in these fibrils. The fibrils are approximately 130-210 nm in diameter.