Shape and size of isolated bone mineralites measured using atomic force microscopy.

The inorganic phase of bone is comprised primarily of very small mineralites. The size and shape of these mineralites play fundamental roles in maintaining ionic homeostasis and in the biomechanical function of bone. Using atomic force microscopy, we have obtained direct three-dimensional visual evidence of the size and shape of native protein-free mineralites isolated from mature bovine bone. Approximately 98% of the mineralites are less than 2 nm thick displaying a plate-like habit. Distributions of both thickness and width show single peaks. The distribution of lengths may be multimodal with distinct peaks separated by approximately 6 nm. Application of our results is expected to be of use in the design of novel orthopaedic biomaterials. In addition, they provide more accurate inputs to molecular-scale models aimed at predicting the physiological and mechanical behavior of bone.