Smallest-ever Leiden University logo
The logo of Leiden University, with letters as small as a bacterium. Researchers from LUMC and the Institute of Biology have created the smallest logo of our university ever produced. It is a piece of fun with a serious real-world application: the new microscope with which the logo was made allows scientists to look into cells even more closely.
Sometimes the easiest way to find out how something works is to examine it minutely. The same is true for cell biology: by examining cells ever more closely, we are able to learn a lot about the mechanisms within the cells. Cryo-electron microscopy is often used to do this: biological samples are examined at 165 degrees below zero (or even colder) under an electron microscope. This creates an image of the cell in its natural state. The development of this technique was awarded last year’s Nobel Prize in Chemistry.
Opening cells
Until now, however, it was only possible to view very small samples, including individual proteins, viruses and small bacterial cells. The Institute of Biology (IBL) has now purchased a new type of cryogenic microscope, with which more complex samples such as a cluster of cells or a piece of tissue can be viewed. The state-of-the-art device can 'open up' a very specific part of a cell while the cell remains in its natural state due to the cryo-temperature. By using an ion beam, the outer layers of the cell are shaved away with nanometer precision, leaving a very thin cell layer. The researchers can follow this shaving process accurately with the built-in microscope. Then, an image can be made of the interior of the cell through the thin layer that has been created. The transmission electron microscopes at the Centre for Nanoscopy (NeCEN) of the IBL makes this possible even at molecular level.
Bacterial-size letters
The researchers have to undergo an extensive training to learn how to work effectively with the ion beam. As an exercise in precision, they carved the logo of Leiden University into a plate on which microscopy samples are placed. The letters of the logo are the size of bacteria: the large letters are the size of a Streptomyces bacterium – the bacterium that produces most types of antibiotics – and the dots on the ‘i’s’are about the same size as a Vibrio cholerae, the bacterium that causes cholera. Both bacterial species are being studied within the IBL, and the new microscope will also be deployed for this.
