Characterization of the cutting edge of glass knives for ultramicrotomy byscanning force microscopy using cantilevers with a defined tip geometry

The geometry of glass knife edges for ultramicrotomy was studied with nanos cale resolution using scanning force microscopy (SFM) in the contact mode. The local shape of the cutting edge was estimated from single line profiles of the SFM topographic images by taking into account the exact radius of t he ultrasharp silicon tip. The tip radius was estimated from secondary elec tron micrographs recorded at low voltage by field emission scanning electro n microscopy (FESEM). The radius of the investigated cutting edges was foun d to be in range 5-20 nm. The results obtained illustrate that the combinat ion of SFM and high resolution FESEM provides a unique means to determine p recisely the radius of glass knives.