Multi-user equipment approved in grant 14/50906-9 - cryotransfer holder for TEM

Abstract

The objective of this project is the acquisition of accessories that will be installed in an Electronic Transmission Microscope (Libra 120 - Zeiss), which was acquired as part of an INCT / Inomat project already closed (Proc. Fapesp 2008/57867-8). The current project aims to increase the analytical capacity of the microscope by implementing electronic cryomicroscopy techniques. In this technique, the samples are prepared and examined in the form of ultra-thin films whose matrix is vitrified water. This dispenses with the contrast application or fixation steps, which may introduce contaminants into the sample thus causing the appearance of artifacts. This technique is especially important in water soluble or dispersed samples, biological or otherwise: emulsions, micelles, nanoparticles, nanoaggregates, biomacromolecules and nanostructures of biological origin. In addition, non-hydrated samples that are very sensitive to the electronic beam may benefit from the cryomicroscopy examination, since the samples are kept at a low temperature. The Libra 120 microscope in which this equipment will be installed has been intensively used in research on nanocomposites, polymers and even some electron beam sensitive samples that cannot stand electrons accelerated to high voltages (nanoparticles and polymer nanowires). Under current conditions, the hydrated samples require previous intensive drying for analysis and sometimes they have to be processed with fixative and / or contrast-enhancing elements, such as uranium, to achieve sample stability and contrast. This type of treatment will be dispensed with the possibility of cryomicroscopy examination. In the desired configuration, this instrument will allow the combination of up to three powerful tools: electron energy loss spectroscopy, electronic tomography and cryomicroscopy, in a combination that is not often found, even in laboratories with excellent facilities. The implementation of cryomicroscopy in this laboratory will allow important progress in Inomat current research project (Proc. FAPESP 2014 / 50906-9), especially in the activities of nanotoxicology and in the development of new polymer or hybrid nanostructures. (AU)