microscope

The microscope is one of the most important medical instruments. It is indispensable for the diagnosis of numerous diseases.

What is a microscope?

With the help of a microscope, very small objects can be enlarged so much that they can be represented graphically. As a rule, the objects to be examined are of a size that is below the resolution of the human eye. The technique in which the microscope is used is called microscopy.

The microscope is particularly important in medicine for performing various examinations. It is also used in biology and materials science.

Basically, the microscope is one of the most important inventions of mankind. A large number of scientific and medical questions could be answered using this instrument. The term microscope or microscopy comes from ancient Greek. While Mikros means “very small” in German, Skopie means “to look at”.

Shapes, types & types

A distinction is made between different types of microscope. These are the light microscope, the electron microscope and the scanning probe microscope. The oldest and best-known technique is light microscopy. It was brought into being around 1595 by Dutch eyeglass grinders and lens technicians. The objects are viewed in light microscopy through one or different glass lenses. The maximum resolution of a classic light microscope depends on the wavelength of the light that is used. There is a limitation of around 0.2 micrometers. The name for this limit is the Abbe limit. This is how the German physicist Ernst Abbe (1840-1905) described the corresponding laws. From the 1960s onwards, microscopes were also developed that were beyond Abbe's resolution limits.

An even higher resolution is possible with the help of electron microscopes. These instruments were made in the 1930s. The German electrical engineer Ernst Ruska (1906-1988) was the inventor of the electron microscope. The electron beams have a shorter wavelength than light, which enables a closer look. In this way, medicine and biology had even better examination options, as they could also use an electron microscope to inspect objects that were no longer possible with a light microscope. These include a. Viruses, Prions, Chromatin and DNA.

Another variant of the microscope is the atomic force microscope. It was developed in 1985 by Gerd Binnig, Christoph Gerber and Calvin Quate. The special scanning probe microscope is equipped with fine needles that are used to scan surfaces. Their functionality is based on a different principle.

The use of light microscopes, scanning probe microscopes and electron microscopes takes place in numerous different variants. For example, there is the magnetic resonance microscope, the X-ray microscope, the ultrasound microscope, the neuron microscope and the helium-ion microscope.

Structure & functionality

The structure of a conventional microscope consists of a stand that is attached to a heavy foot and ensures the stability of the instrument. The light is generated on the underside with an electric light source or a mirror. With the help of an adjustable diaphragm, known as a condenser, the light can be directed onto the slide from below through an opening in the specimen stage. The object to be examined is accommodated in the slide. Two metal clamps ensure the stability of the slide so that the image does not shake.

Another important component of the microscope is the optical apparatus. This includes different objects with several magnification factors that are located on the rotating turret. The magnification is usually 4x, 10x, or 40x. In addition, 50x and 100x objectives are also available. With the help of a mirror that is housed in the tripod, the light finds its way to the tube. It then falls into the eyepiece through which the object can be viewed.

A light microscope works by looking at the object against the light. The light, which is also known as the beam path, begins at the light source under the slide. The object is penetrated by the light, which creates a real intermediate image with the lens inside the tube. The microscope's eyepiece acts like a magnifying glass, which in turn creates a significantly enlarged virtual intermediate image.

Medical & health benefits

The use of the microscope is of fundamental importance for medicine. It is primarily used to assess tissue samples, microorganisms, blood components and cells. In particular, the identification of germs such as bacteria or fungi is often indispensable in order to carry out a suitable therapy.

With the help of microscopic examinations, the medical professionals can detect certain pathogens. For this purpose, infected samples such as blood, wound secretion or pus are examined under a light microscope to determine the causative bacterium. However, viruses can hardly be detected with a light microscope. This is only possible with an electron microscope.

Microscopic examinations also play an important role in early cancer detection. Tissue samples obtained from a biopsy or a cell smear are examined with the instrument in order to clarify a suspected cancer. But the microscope also provides valuable information after the tumor has been surgically removed. So u. a. determine what type of cancer it is and whether the tumor is aggressive or is growing slowly.

Special medical examinations are carried out with the microscope in pathology laboratories that specialize in this diagnosis.