Microscopy And Microscope

Microscopy And Microscope

Microscopy

• Microscopy is the technical field of using microscopes to view samples and objects that cannot be seen with the unaided eye (objects that are not within the resolution range of the normal eye).
• So, it is the examination of minute objects by means of a microscope, an instrument that provides an enlarged image of an object not visible with the naked eye.
• There are three well-known branches of microscopy: optical, electron, and scanning probe microscopy.

Microscope

• The microscope is the instrument most characteristic of the microbiology laboratory.
• Microscopes are devices that are used to magnify small objects.
• The magnification it provides enables us to see microorganisms and their structures otherwise invisible to the naked eye.
• The magnifications attainable by microscopes range from X100 to X400,000.
• They come in a wide range of shapes and sizes and use many types of illumination sources (light, electrons, ions, x-rays and even mechanical probes) and signals to produce an image. 
•  A microscope can be as simple as a hand-held magnifying glass or as complex as a multi-million-dollar research instrument.
• Each type of microscopy and each method of preparing specimens for examination offers advantages for the demonstration of specific morphological features.
• Microscopes are of two categories, light (or optical) and electron, depending upon the principle on which magnification is based.
• Light microscopy, in which magnification is obtained by a system of optical lenses using light waves, includes (l) bright-field, (2) dark-field, (3) fluorescence, and (4) phase-contrast microscopy.
• The electron microscope, as the name suggests, uses a beam of electrons in the plage of light waves to produce the image.
• Specimens can be examined by either transmission or scanning electron microscopy.
• In addition, several different kinds of microscopy are available, and many techniques have been developed by which specimens of microorganisms can be prepared for the examination.

•  In the first microbiology course, students perform most of their examinations, if not all, with the bright-field microscope.
• This is the most widely used instrument for routine microscopic work.
• The other types of microscopy are used for special purposes or research investigations.
• However, students should be acquainted with their applications, since, each has some unique feature that is useful for demonstrating particular structures of the cell.

Applications:

• The goal of any laboratory microscope is to produce clear, high-quality images, whether an optical microscope, which uses light to generate the image, a scanning or transmission electron microscope (using electrons), or a scanning probe microscope (using a probe).
• Upright microscopes are the most common type, with the lighting system below the stage and the lens system above; inverted microscopes, particularly useful for cell culture, reverse this configuration.
• Applications include biotechnology, pharmaceutical research, nanophysics, microelectronics, and geology.
• Commonly used compound microscopes are usually binocular (two eyepieces) and use multiple lenses to produce a 2-D image.
• They can achieve a maximum of about X1000-X2000 magnification and are popular for use in biology and in forensic labs.
• Stereo microscopes offer 3-D viewing at lower magnification and are available in fixed and zoom variations.
• Digital microscopes eliminate eyepieces, combining optics with a CCD camera to view images on a computer screen.
• Techniques range from simple brightfield to darkfield, phase contrast, differential interference contrast, confocal (useful for thick specimens), and fluorescence microscopy, which continues to prove its value in areas such as cell biology, genetics, and embryology.
•  The use of polarized light in polarizing microscopes results in increased image contrast.
• Optical and electron microscopy involve the diffraction, reflection, or refraction of electromagnetic radiation/electron beams interacting with the specimen, and the subsequent collection of this scattered radiation or another signal in order to create an image.
• This process may be carried out by wide-field irradiation of the sample (for example standard light microscopy and transmission electron microscopy) or by scanning of a fine beam over the sample (for example confocal laser scanning microscopy and scanning electron microscopy).
• Scanning probe microscopy involves the interaction of a scanning probe with the surface of the object of interest.
• The development of microscopy revolutionized biology and remains an essential technique in the life and physical sciences.

References:

• https://www.labcompare.com/Microscopy-and-Laboratory-Microscopes/243-Laboratory-Microscopes/
• https://www.medicinenet.com/script/main/art.asp?articlekey=13024
• https://www.microscopy.co.za/what-is-microscopy
• https://www.khanacademy.org/science/high-school-biology/hs-cells/hs-introduction-to-cells/a/microscopy
• https://en.wikipedia.org/wiki/Microscopy