Scientists at Vanderbilt University have developed a potential new technique using electron microscopy to view gold nanoparticle-tagged proteins on the move in undamaged, whole cells.
Niels de Jonge, assistant professor of physiology and biophysics at the Vanderbilt University, stated that the novel technique can also be used in materials and energy sciences. Establishing the location of proteins within intact cells can help researchers understand cancer processes and the process of how viruses force themselves into healthy cells and then hijack them, de Jonge added.
Current methodologies used for protein study have limitations. Transmission electron microscopes can determine individual protein locations, but for that the cell has to be frozen, cut and then placed in a vacuum for imaging. Optical microscopes can achieve a resolution of 50 nm, which is not sufficient to view individual proteins.
Scientists have so far not been able to view proteins on the move directly. The Vanderbilt researchers employed a scanning transmission electron microscope (STEM) for watching proteins 'in action.' They utilized the annular dark-field (ADF) imaging STEM analysis technique for detecting the proteins. Gold nanoparticles were tagged onto the proteins. ADF detectors are less sensitive to carbon and water and more sensitive to elements such as platinum and gold. The cells are surrounded by a liquid and are placed within a microchip device that has the capability to withstand the vacuum of the STEM. The cells are not alive. The researchers achieved ten times better resolution than optical microscopes using this technique, which was around 4 nm.
When used in combination with optical microscopy the technique can be a powerful tool for study, stated de Jonge. The study results are to be presented at the 58th AVS International Symposium & Exhibition being held Oct. 30 – Nov. 4 at the Nashville Convention Center in Tennessee.
Source: http://www.aip.org/