Microscopes are a mainstay in life science research but advances in imaging have allowed their use to expand into most areas of science and technology. They are commonly used to view different types of cells, analyze clinical specimens and to scan nanomaterials. The three main categories of microscopy are defined by the method used to magnify the sample and they are: optical, electron and scanning probe.
Applications:
Microscopy is used in many fields and microscopes are useful for different types of imaging. These tasks include, but are not limited to:
- Fluorescence imaging
- Cell imaging
- 3D imaging
- Live cell imaging
- Tissue imaging
- Clinical laboratory imaging
Range of Microscopes:
Many different types of microscopes exist and finding the right one for your lab depends on the type of imaging desired.
Light Microscopes are ideal for viewing living or dead samples looking at either the surface or a cross-section of the sample. This class of microscopes is by far the most commonly used in life science research particularly when used in conjunction with fluorescently labeled antibodies or reporters to identify cellular processes or protein localization.
Electron Microscopes use an electron beam (instead of a light beam) to produce an image of the sample; because the wavelength of an electron is around 100,000 times shorter than that of a photon of light, images can be viewed with a resolution down to around 50pm. Scanning electron microscopes (SEM) and transmission electron microscopes (TEM) are the two main types of electron microscopes and they can be used for cell surface imaging, trace evidence analysis and single particle analysis. Often microscopes come bundled with a computer for automatic data collection and image analysis.
Considerations when selecting a microscope:
Since a microscope is first and foremost an optical device, quality optics are of primary importance in selecting an instrument. The ocular lens brings the image into focus and provides a certain amount of magnification. The objective lens is responsible for the primary image formation and is central to determining the quality of images a microscope can produce. The resolution limit of a microscope is determined by the objective lens characteristics, including the wavelength of light used to illuminate the specimen, the angular aperture and the refractive index in the space between the objective front lens and the specimen.
Selecting a microscope is largely dependent upon your sample. You may wish to view a live sample, determine the fluorescence of a sample or count cells. After application-specific choices and quality optics, one might consider a wide array of features and conveniences, such as slide scanning, programmable controls or included software, the available range of magnification, filtering, noise reduction, ease of use, size and ergonomics.