A new longitudinal variation in the structure of collagen fibrils and its relationship to locations of mechanical damage susceptibility.

The hierarchical architecture of the collagen fibril is well understood, involving non-integer staggering of collagen molecules which results in a 67 nm periodic molecular density variation termed D-banding. Other than this variation, collagen fibrils are considered to be homogeneous at the micro-scale and beyond. Interestingly, serial kink structures have been shown to form at discrete locations along the length of collagen fibrils from some mechanically overloaded tendons.