PERFORATED SUPPORT FOILS WITH PREDEFINED HOLE SIZE, SHAPE AND ARRANGEMENT

Perforated support foils with holes of pre-defined size, shape and arr angement and with hole sizes down to the sub-micrometer range, named Q uantifoil, are presented. The foils are fabricated using semiconductor lithographic techniques. For the first time, a sacrificial layer that consists of a biopolymer, i.e, glutaraldehyde cross-linked gelatin, i s used. This layer is removed by proteinase treatment, thus introducin g an enzymatic reaction as a tool in microsystems technology. The foil s are particularly beneficial in electron microscopy, when a specimen support is required with holes smaller than those attainable with meta l grids (similar to 10 mu m). Their advantages in cryo-electron micros copy, for example, are illustrated. Furthermore, foils with a specific hole size and arrangement permit a further automation of electron mic roscopic (EM) data acquisition procedures. (C) 1998 Elsevier Science B .V. All rights reserved.