Bergenia Under the Microscope: How Is a Flower Photo Made Using an Electron Microscope?

What exactly is a Scanning Electron Microscope (SEM)?
A Scanning Electron Microscope, or SEM for short, is a special device that uses electrons instead of light to create a highly detailed image of a sample’s surface. Electrons have a much shorter wavelength than light, so they can reveal structures on the micro- and even nano-scale, which are unattainable for a regular optical microscope. The SEM “scans” the sample’s surface in small sections, creating a black-and-white image with tremendous depth of field, allowing us to see the surfaces of flowers, pollen grains, or even butterfly wings in incredible detail. This microscope is a key tool in biology, material sciences, and industry – and at our faculty, you can learn to work with too.

How is a flower photographed using an SEM?
In spring, everything is in bloom, and the microscopists (simply someone who loves microscopes) heads out into the field. They pick fresh flowers, stick them onto a special holder using double-sided tape, and prepare them for a big adventure. Because flowers are non-conductive, they must be coated with a thin layer of metal – such as gold and palladium. This prevents electrical charge from building up on them during observation.

Then, the sample is placed into the vacuum chamber of the electron microscope, the magnification is set (which can be truly wild – from 6x up to a million times!), focused, and… click! A black-and-white image appears on the monitor, which you can later colorize on the computer if you wish.

Can you describe what working with a scanning electron microscope looks like at your department?
We have a microscope with a large chamber, into which you can place objects the size of a paving stone or a tennis ball. Most often, though, we work with flatamples about 1 cm² in size. We obtain various types of information from them – for example, using a secondary electron detector, which provides spatially expressive black-and-white images of the surface. Other detectors allow us to determine the material’s composition or create color maps of the distribution of elements. However, these colored images are mostly the result of post-processing, where colors are assigned artificially for better clarity.

Do you enjoy the creative part of coloring the images?
Honestly, I prefer automated processing, where the machine creates color maps of elements based on data. On the other hand, coloring images is laborious, but even someone without much artistic talent can do it if they have a sharp image with good contrast and suitable software tools. The result is nicely defined and color-differentiated areas in the images.

Can you tell us more about automated data processing and color element maps in electron microscopy?
Absolutely! In electron microscopy, we have various detectors at our disposal that, in addition to classic black-and-white images of the surface created by electrons, can also provide information about the chemical composition of the sample. These detectors, for example, capture X-rays generated by the interaction of electrons with the sample, which allows us to determine which elements are present on the surface and how they are distributed.
Automated processing means that the computer itself creates color maps of elements based on this data – that is, images where individual elements are marked with different colors. This is a big advantage compared to manual coloring, which is very labor-intensive and requires a lot of time and artistic sense. Moreover, manual coloring is not objective, because colors are assigned by a person according to their own judgment.
Thanks to automation, we get precise and clear distribution of elements in the sample, which helps us better understand its structure and properties. Color maps are not only beautiful to look at, but above all scientifically valuable. This process significantly speeds up analysis and allows us to focus on interpreting results and further scientific research.
So even though coloring images can be fun, automated processing is efficient, precise, and opens up new possibilities in microscopic analysis. And best of all – at our faculty, you can learn how to work with these technologies!

When you were a child, did you want a microscope, or did microscopes start to interest you later?
Already in elementary school, I was fascinated that with a microscope I could see things invisible to the naked eye. My first microscopic memory is the classic observation of onion cells, when you first see cell nuclei and walls. That’s an experience I remember to this day – suddenly you see a completely new world.

When did you first encounter an electron microscope?
I only encountered electron microscopy at university, when I started teaching optics and optometry. Back then, I had the opportunity to work with various optical microscopes, and later I was offered the chance to take care of a scanning electron microscope. At first, I hesitated because I knew nothing about electron microscopy. Gradually, I got into it, and today I really enjoy electron microscopy.

What fascinates you most about microscopy?
The fascination lies in the fact that you can put almost anything into an electron microscope and discover something new about it. For example, the surface of plants hides many structures that are invisible to the naked eye – various hairs, bottles, spines, or the famous stinging nettle, whose stinging mechanism is beautifully visible under the microscope. Working with colleagues who can name and explain these things is extremely inspiring. Together, we create the scientific story of what we are imaging.

How do students get involved in working with microscopes?
Students have the opportunity to get acquainted with microscopes as part of their studies, where they undergo short training and demonstrations of methods. Some then choose a bachelor’s or master’s thesis focused on microscopy, and those receive more thorough training and specialization in specific samples. If they are capable and reliable, they can then measure independently.

Why is Brno talked about as a center of microscopy?
Brno is unique in the world in that three companies producing electron microscopes are based here, together accounting for about a third of the world’s production of these devices. That also means a quarter of the global turnover in the field. These companies need qualified workers of various specializations – from theorists to experimenters, to graphic designers and operators. Studying at our Faculty of Science and subsequently working in these companies is therefore a great choice. Brno has a great future in this field and is at the global forefront.

Is it possible for graduates to find jobs abroad?
Yes, I know of cases where students, after completing their bachelor’s and master’s studies in Brno, went, for example, to Canada, where they were in high demand thanks to their knowledge and experience with electron microscopes. They thus gained not only international experience but also recognition in the field.

Fluffy few-layer graphene nanosheets synthesized in the gas-phase by decomposition of ethanol in the microwave plasma at atmospheric pressure. Nanosheets are stabilized by curving of their edges and bonding hydrogen to the unsaturated dangling bonds in the periphery of the hexagonal network. Gas-phase synthesized graphene exhibits exceptionally high and tunable high-temperature oxidation resistance controlled by the amount of structural disorder formed directly during its growth.