Researchers at ORNL and Vanderbilt University have unveiled a new technique for imaging whole cells in liquid using a scanning transmission electron microscope. Electron microscopy is the most important tool for imaging objects at the nano-scale the size of molecules and objects in cells. But electron microscopy requires a high vacuum, which has prevented imaging of samples in liquid, such as biological cells." The new technique — liquid STEM — uses a micro-fluidic device with electron transparent windows to enable the imaging of cells in liquid. A team led by Niels de Jonge imaged individual molecules in a cell, with significantly improved resolution and speed compared with existing imaging methods. "Liquid STEM has the potential to become a versatile tool for imaging cellular processes on the nanometer scale," said de Jonge. "It will potentially be of great relevance for the development of molecular probes and for the understanding of the interaction of viruses with cells." The work was recently described in the on-line Proceedings of the National Academy of Sciences.