Scientists have used different types of microscopes to observe objects since the 17th century. However, the earliest microscopes did not look like the ones today. Scientists and researchers put more effort into modifying previous microscopes and designing more advanced instruments.
Ultramicroscope and electron microscope are two such pieces of equipment developed after extensive study of different aspects of microscopy. They enable you to observe minute-sized particles you cannot see under a compound microscope.
The electron microscope uses a beam of electrons to create a detailed specimen image. Contrarily, ultramicroscopes allow you to see objects with a shorter diameter than the wavelength of visible light. The diameter makes it difficult to observe such objects under visible light. In terms of intricate observation, electron microscopes deliver better precision than ultramicroscopes by providing a clear image.
Let’s tell you the characteristics and differences between ultramicroscope and electron microscope in-depth for better understanding.
Comparison Table
| Characteristics | Ultramicroscope | Electron Microscope |
| Development | 1902 | 1931 |
| Source of Illumination | Scattered UV rays | Electron Beam |
| Imaging | Bright spots on dark background | Clear images on the ocular lens |
| Condenser | Cytoviva-enhanced darkfield illumination | Electromagnetic lens |
| Specimen | Dispersed colloidal particles | Non-living biological & non-biological samples |
| Application | Brownian motion, biological ultrastructure examination | Biological and inorganic sample study and quality analysis |
Ultra Microscope
Ultra Microscopes are high-intensity illumination microscopes that observe objects with a diameter shorter than the wavelength of visible light. They are typically used to keep colloidal particles that scatter the light and appear as bright spots on a dark background. This type of microscopy is also called dark-field microscopy.
History
While observing prepared slides with specimens having a diameter shorter than the wavelength of visible light, such as colloidal particles, researchers faced problems studying the specimen. Thus, Richard Adolf Zsigmondy and Henry Siedentopf developed the ultramicroscope in 1902. They determined the size of 4nm nanoparticles in cranberry glass using bright sunlight for illumination. These scientists further improved ultramicroscopes, giving birth to immersion ultramicroscopes to observe suspended nanoparticles in defined fluidic volumes. Richard Adolf Zsigmondy received the Nobel Prize in Chemistry in 1925 for his study on ultramicroscopes and colloids.
Working Principle
The working principle of ultramicroscopy is the same as dark field microscopy, in which bright spots appear on a dark or black background. The microscope makes use of a high numerical aperture illumination. The Cyto-viva condenser arrangement allows you to observe the samples through a quasi-perpendicular illumination preventing direct illumination from entering the objective lens. So, the lens only detects the photons scattered by the particles in the direction of the objective lens. It is similar to seeing dust particles in the air when the sun illuminates them on a dark background to see on the ocular lens.
Particle Measurement
The nanoparticles observed by the scattered photons appear in the objective lens representing a bright illuminated object over a dark background. Besides viewing the specimen, the ultramicroscope also measures the size distribution by following the individual particles.
Eventually, you can calculate the diffusion coefficient offline by applying the Stokes-Einstein equation. It gives you the size of every particle passing the field of view of the ultramicroscope. However, the size determination method in ultramicroscopy depends on the light scattering techniques.
Condenser
Ultra Microscopes have a Cytoviva-enhanced darkfield illumination system to observe the colloidal particles of nanosize. The illumination source focuses on highly collimated light on oblique angles with fixed geometry on the specimen. It helps improve contrast and provides optimized resolving power to non-fluorescing samples for better imaging.
Sample Requirements
Ultra Microscopes observe nanoparticles that you cannot see in ordinary light microscopes. Dispersion of nanoparticles in any solvent allows you to study them thoroughly through dispersed particles.
Electron Microscope
An electron microscope is the most advanced equipment to see micro details on organisms and objects. You can observe biological and non-biological specimens with electron microscopes. You can observe objects magnified up to 10,000,000x, with a resolution of 50 picometers. Opposed to ultra or light microscopes, electron microscopes use an electron beam to illuminate the object under observation.
History
Hans Busch developed the first electromagnetic lens in 1926 and filed a patent for the electron microscope two years later. However, the first electron microscope was constructed by Ernst Ruska and Max Knoll with 400x magnification. While Ernst Ruska, Bodo von Borries, and Helmut Ruska worked to improve the magnification of the electron microscope, Manfred von Ardenne created the first scanning electron microscope. The electron microscope won Ernst Ruska the Nobel Prize in Physics in 1986. Heinrich Rohrer and Gerd Binnig shared the award for developing the Scanning Tunneling Microscope.
Working Principle
The electron microscope works on an entirely different method than the working principle of compound or ultra microscopes. The electron microscope uses electrons to obtain information about the structure and properties of the specimens. The electron gun generates electrons that the condenser lenses and voltage focus into a 200x thinner beam. The thin electron beam falls on the object, scattering according to the refractive index of the specimen components. The darker areas on the object scatter more electrons. The objective lens picks the image, which is then focused onto the ocular lens.
Particle Measurement
An electron microscope makes it incredibly easy to measure the size and diameter of the specimen with high precision. It uses automated software to produce multiple images and calculate the distribution of particles.
Condenser
Typically electron microscopes consist of two condenser lenses that work to centralize the electrons to produce a sharp image of the sample. The first lens de-magnifies the electron beam and converges into a thin beam of ～1/10 in size. The second condenser lens transfers the beam onto the objective lens to produce an image on a clean ocular lens.
Sample Requirements
Electron microscopes offer an in-depth analysis of all kinds of biological and non-biological samples up to 0.2 microns. They are considered the best microscopes for microbiology and molecular biology. Some electrons may also study atoms to provide better insight into the observation. However, the only drawback of observing specimens in an electron microscope is its inability to study living objects.
Differences between Ultramicroscope and Electron Microscope
Development
Richard Adolf Zsigmondy and Henry Siedentopf developed the ultramicroscope in 1902, which could study 4nm nanoparticles in cranberry glass using bright sunlight.
Conversely, Hans Busch developed the first electromagnetic lens in 1926, and Ernst Ruska and Max Knoll invented the first microscope in 1931.
Source of Illumination
An ultramicroscope illuminates objects using scattered ultraviolet radiation instead of the light absorption technique.
On the contrary, electron microscopes use a beam of electrons to brighten the specimen for observation.
Imaging
Imaging in an ultramicroscope is not as clear as in an electron microscope as the object appears as spots on a dark background.
However, an electron microscope produces a clear image on the ocular lens through the condenser and objective lens.
Condenser
Ultramicroscopy consists of a Cytoviva-enhanced darkfield illumination system focusing highly collimated light on oblique angles.
Alternatively, electron microscopes use two condenser lenses; the first demagnetizes the electron beam, and the next converges and controls the convergence angle.
Specimen Requirements
Ultra Microscopes typically observe dispersed nanoparticles or colloids of smaller sizes to study their properties.
On the other hand, an electron microscope is only suitable for non-living samples as the bombardment of electrons kills living cells.
Application
Ultra Microscopes have been used to observe colloids and aerosols, study Brownian motion and examine biological ultrastructures.
Electron microscopes help investigate biological and inorganic samples, including cells, molecules, metals, and quality analysis.
The Bottom Line
Ultra Microscopes have been widely used, while electron microscopes are more utilized in research and scientific studies. Electron microscopes help you analyze objects at a higher magnification than the standard compound microscope. Ultra Microscopes use bright illumination to produce observations on a dark background. Consequently, electron microscopes use an electron beam converged to create images on the ocular lens. Besides their illumination source, the type of observation is a distinct difference between ultra and electron microscopy. The former is used to observe colloids and ultrastructures, whereas the latter studies various biological and inorganic samples. Various microscope brands, like the OMAX and AmScope, offer different options to select from. Choose which suits you the best.
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