FIB characterisation of cell/device interface

Abstract

Cryo‐preparation of biological samples for electron microscopy has many advantages against the chemical fixation. Cryo‐fixation is extremely rapid which can inhibit, within milliseconds, the intracellular movements of macromolecules and other substances. Due to its rapidity, it may even allow the detection of the processes of contacting between the vesicles and the membrane in the cells. One can try to capture the processes at synapse contact, which would be impossible with much slower chemical fixation. The problems may arrive if the biological sample is contacting to the solids for example at the interface of biological sensor. Due to different thermal expansion coefficient of the solid and biological materials, it may lead to unwonted artefacts at the interface area. We will present the information about the interface between our structurally modified biosensors and biological cells of different preparation techniques. We have used cryo‐fixation, standard chemical fixation with critical point drying and epoxy embedding. For characterisation of the interface, we apply SEM and FIB (FEI Helios NanoLab DualBeam) sectioning at cryo‐ and room temperatures.