FLUORESCENCE MISCROSCOPY

FLUORESCENCE MISCROSCOPY

WHY IN NEWS?

• Recently, researchers at the Winona State University, Minnesota, have created a design for a ‘glowscope’.

WHAT IS GLOWSCOPE?

• It is a device that could democratise the access to fluorescence microscopy.
• Glowscopes may be suitable for some research applications.
• Its development was to meet the needs of science educators and outreach programs.

WHAT IS FLUORESCENCE MICROSCOPY?

• It is an optical microscope that views an object by studying how it absorbs, reflects or scatters visible light.
• A fluorescence microscope views an object by studying how it re-emits light that it has absorbed, i.e. how it fluoresces.
• There are versions of fluorescent microscopes with more sophisticated abilities, such as epifluorescence and confocal laser-scanning microscopes.
• Fluorescence microscopes range in cost from several thousand to several hundred thousand US dollars.

FUNCTIONING OF FLUORESCENCE MICROSCOPY

• The object is illuminated with light of a specific wavelength.
• Particles in the object absorb this light and re­emit it at a higher wavelength (i.e. different colour).
• These particles are called fluorophores.
• When the fluorophores fluoresce, a fluorescent microscope can track them as they move inside the object, revealing the object’s internal shape and other characteristics.

USE OF FLUORESCENCE MICROSCOPY IN BIOTECHNOLOGY

• A fluorophore called the Hoechst stain binds to the DNA and is excited by ultraviolet light.
• So, a tissue sample collected from a person could be injected with the Hoechst stain and placed under a fluorescent microscope.
• When the sample is illuminated by ultraviolet light, the stain absorbs the light and re­emits it at a higher wavelength.
• The microscope will point out where this is happening: in the nuclei of cells, where DNA is located.
• This way, the nuclei in the tissue can be labelled for further study.
• Scientists have developed different fluorophores to identify and study different entities, from specific parts of the DNA to protein complexes.

BENEFITS OF GLOWSCOPE

• The researchers were able to image the creatures’ brain, spinal cord (using a fluorophore called DsRed), heart (mCherry), and head and jaw bones (mRFP).

• They were able to zoom in and out using the smartphone camera and the clip-on lens, and by adjusting the distance between the sample and the smartphone platforms.
• To detect green and red fluorophores and to monitor and detect changes to heart rate and rhythmicity in embryonic zebrafish.

FUNCTIONING OF GLOWSCOPES

• Their set­up consists of two plexiglass surfaces, an LED flashlight, three theatre stage-lighting filters, a clip-on macro lens, and a smartphone.
• The smartphone (with the lens attached) is placed on one surface that is suspended at a height (say, a foot above).
• The second sheet is placed below and holds the object.
• One of the stage-lighting filters was held between the flashlight and the object and the other two were held between the object and the smartphone.

• The role of these filters was to ensure that light of the right frequency reached the object and that fluoresced light of a suitable frequency reached the camera.

CHALLENGES IN THE USE OF GLOWSCOPE

• The total estimated cost of set­up used to obtain these microscopes range in cost from several thousand to several hundred thousand US dollars.
• Such huge cost can prevent many individuals in India to get access to latest technological interventions.
• Using a ‘glowscope’ still requires access to fluorophores, suitable biological samples, the know­how to combine the two, and some knowledge of physics to work out which LED flashlight to buy.

WAY FORWARD

• Instead of being entirely out of reach, researchers can prepare samples from fluorescent microscope, which can be set up with a few thousand rupees and then take them to schools where students can observe them using glowscope.
• The Foldscope was truly remarkable because all its required components were simple to understand.
• Researchers and students in resource­ poor labs can also use foldscopes and ‘glowscopes’ together to learn more about the microscopic affairs.

SOURCE : THE HINDU

SYLLABUS : MAINS, GS-3, SCIENCE&TECHNOLOGY