A search for apatite crystals in the gap zone of collagen fibrils in bone using dark-field illumination

Bright-field transmission electron microscope (TEM) images of ion milled or focused ion beam (FIB) sections of cortical bone sectioned parallel to the long axis of collagen fibrils display an electron-dense phase in the gap zones of the fibrils, as well as elongated plates (termed mineral lamellae) comprised of apatite crystals, which surround and lie between the fibrils. Energy dispersive X-ray spectroscopy (EDS) and electron energy loss …