Observing DNAs by murkiness
Researchers at the Kavli Institute of Nanoscience Delft have developed a breakthrough method to detect alien material, such as the coronavirus, in genes. The result is visible to the naked eye in about one hour. “The method does not need a lot of chemicals or high-tech equipment, making it cheap and sustainable,” says the researcher Kasper Spoelstra.
The main muscle behind the new methodology is CRISPR-Cas proteins. These are genetic cutters that can edit DNA molecules with extreme precision. In this study, the researchers apply new proteins: Cas12a and Cas13a. If the commonly used Cas9 is compared to a scalpel, these are the shredders.
Detecting DNA is quite tricky because of its minuscule scale. Spoelstra and his team used a clever way, inspired by a water and oil emulsion made of countless tiny droplets, to observe the molecular activity with the naked eye.
The shredders will only chop the sample DNA if the identification is positive – which means that there is something wrong in the DNA – leaving the surrounding liquid clear. When the proteins do not find any cleaving point, an emulsion forms, and the liquid becomes murky from the droplets. That means a negative result, and the DNA is in good shape.
There is a catch though! This technique is only applicable to DNAs with long strands (> 200 nm) as the water remains clear with the short ones, even when the result is negative.
Rayan Suryadikara / Science Desk Intern
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