Explaining Diamond Knives

Glass knives for cutting ultrathin sections for electron microscopy were first introduced by Latta and Hartman in 1950, replacing the almost impossible process of sharpening metal knives or blades to an edge suitable for ultramicrotomy. In 1953 Dr Humberto Fernandez Moran published his results with the sharpening of gem quality diamond knives (thus free of flaws) for ultramicrotomy and eventually set up a group manufacturing diamond knives in his native Venezuela. Initially specimens sectioned were soft metals but this rapidly expanded into the biological sciences. The manufacturing process was slow and delivery for new knives was at least 12 months although each knife was delivered with a panoramic photo of the entire cutting edge. He also designed an ultramicrotome which was built and marketed by Leitz and could be adapted for cryoultramicrotomy.