Context: 

Researchers at the Winona State University, Minnesota, have created a design for a ‘glowscope’, a device that could democratise access to fluorescence microscopy.

Image Source: The Hindu

What is fluorescence microscopy? 

• An optical microscope 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. This is its basic principle. 
• The object is illuminated with light of a specific wavelength. Particles in the object absorb this light and re-emit it at a higher wavelength (i.e. different colour). 
• These particles are called fluorophores; the object is infused with them before being placed under the microscope. 
• Versions of fluorescent microscopes: epifluorescence and confocal laser scanning microscopes. 
• 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. 
  • For example, 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 re-emits 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.

How does the new device improve access?

• Fluorescence microscopes cost at least a lakh rupee, but often up to crores. The newly invented device will be at a cost of $30-­$50 (₹2,500­- ₹4,100). 
• Many individuals in India may not be able to afford this, but schools and colleges can.
• Using a ‘glowscope’ still requires access to fluorophores, suitable biological samples, the know-how to combine the two, and some knowledge of physics to work out which LED flashlight to buy.
• However, the fact that a simple fluorescent microscope can be set up with a few thousand rupees means, instead of being entirely out of reach, researchers can prepare samples and take them to schools, where students can observe them.

News Source: The Hindu