A SIMPLE FREEZE-FRACTURE TECHNIQUE FOR SCANNING ELECTRON-MICROSCOPY OF COLLAGENOUS BIOMATERIALS

A simple freeze fracture technique for the ultrastructural analysis of fragile collagenous biomaterials is presented. Following standard met hods of preparation and dehydration, fragile biomaterials are fracture d with a sharp blade attached to a modified slide hammer. The sliding mass imparts a sudden impact load on the frozen surface of the materia l, creating a distortion free cleavage plane across the material. More traditional methods including bending and cutting with scissors intro duce artifacts indirectly associated with stress concentration produce d by bending, and sample compression at the edges with cutting. The im pact loading of the sample during fracture results in preservation of edge detail, showing clear structural features up to the surface of th e collagenous biomaterial.