DELMIC Microscopy Blog

Understanding the relationship between structure and function in biology requires continuous developments in the field of microscopy. While electron microscopes and fluorescence microscopes have been go-to techniques for studying organic samples at a high resolution, individually they fall short in offering the exhaustive data needed for truly in-depth life science research.

In 2011, the Charged Particle Optics group at TU Delft completed the development of the SECOM. This system integrates a light and electron microscope, thus combining the labelling capabilities of fluorescence microscopy with the high-resolution nanoscale data obtained from electron microscopy. Six years later, the department of Imaging Physics houses no less than five SECOM systems.

In order to make new discoveries in the life sciences, innovations need to be continuously made in microscopy. This way, scientists can take an ever-closer look at phenomena that are happening on a molecular scale.

Fluorescence microscopy is considered a reliable tool for studying organic samples at a high resolution. Nevertheless, the diffraction barrier of light poses the problem of not being able to distinguish objects that are smaller than the wavelength of light. Proteins, for example, can be as small as four nanometers. Even recent developments in light microscopy - such as super-resolution which can resolve objects at a smaller scale - come with the problem of providing no contextual or structural information besides the objects that glow under fluorescence.

Scientists of all fields are most certainly familiar with the miniature worlds unearthed by electron microscopy. From the complex structures of viruses to extremely small forensic evidence, the revelations brought about by this technology have led to enormous developments in the scientific world. The wavelength of fast electrons is significantly smaller than that of visible light, creating images that were previously unobtainable with conventional light microscopy. For life scientists in particular, the main advantage of electron microscopy (from here on referred to as EM) is the contrast that the black-and-white high-resolution images reveal, providing essential information on the structure of a cell, organelle, or organic tissue.

Characterization at the nanoscale is becoming increasingly important as new discoveries are made and structures are developed at smaller scales. Optical characterization alone is not sufficient to study materials at a scale smaller than the wavelength of light, and electron microscopy results in limited data. This is an issue faced by scientists in fields ranging from materials science to the geosciences. 

This is why DELMIC has developed the SPARC cathodoluminescence (CL) system, which is designed to fit on a scanning electron microscope and detect CL emission using any of available five imaging modes. The SPARC is unmatched in terms of its unique features and high performance, and is recommended for any researcher that wants to keep pace with the competitive scientific community.

Choosing for the right correlative light and electron microscope can be a challenge. It is a sizable investment in terms of time and funding. Furthermore, as knowledge grows in scientific disciplines and as publishing becomes ever more competitive, increasingly complex technology is needed to ensure the accuracy and the integrity of research. In a labyrinth of options, we offer the technology and the ongoing personal service needed for today's ambitious researchers in the life sciences: the SECOM system, and a team of committed engineers to help you throughout the process of your research.

Those who understand the basic mechanisms of cathodoluminescence (CL) know that it is essentially a useful byproduct of electron microscopy. Fast electrons that are fired at a material cause it to become excited, thereby emitting photons of characteristic wavelengths. CL intensity measurement is one of the many useful methods using CL emission to obtain valuable information about your sample complementary to other techniques such as SE, BSE, EBSD or EDS.

This article further explains how CL intensity mapping exactly works and how it can be employed in various types of research.

It is rare that scientific research will rely on a single method. Instead, findings need to be built on multiple types of data to ensure accuracy. For this reason, overlaying images from different microscopes is often a chosen method for researchers, particularly in the life sciences. What is frequently combined is data from an electron microscope (EM) and a fluorescence microscope (FM). These images are then often “overlayed” for a complete picture of the data.

In 1897, the electron was discovered by Sir Joseph John Thomson. The physicist and eventual Nobel Prize winner was in fact conducting research on “cathode rays”. At the time, cathode rays were only known as the consequence of an electric current that was passed through a vacuum tube. It was observed that electrically charged particles would collide with atoms at the end of the tube and excite them, thus causing them to fluoresce, or emit fluorescent light. It was further made evident that these were rays travelling in a straight line from one end of the tube to the next, by placing a shape in the middle of the tube and observing that very shape casting a shadow at the end of the tube.

As a researcher in the life sciences, your work will very likely involve studying various parts of a cell at small length scales. In particular, you may be interested in examining biomolecules and their function within the greater context of the cell as a whole. Recent technological and methodological developments in microscopy have made this process much more straightforward, with integrated fluorescence and electron microscopy. Such a system allows for automatically overlayed images from both an electron and a light microscope, providing you with the ability to identify certain organelles or biomolecules by tagging, at the same time that you are able to localize where they are situated within the cell. More recently, super-resolution fluorescence imaging has been developed, which opens up even greater opportunities for learning about the complexities of life.