Whether nasopharyngeal or salivary, Covid tests must be sent to a specialized laboratory for analysis. Researchers have just developed a “CoroNaspresso” kit to obtain the result at home, using a simple coffee capsule and a pot of boiling water. Here’s how to play little chemist-biologists.
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Around 3.5 million Covid tests are performed each week in France. The tests RT-PCR, which serve as a reference, must be sent to the laboratory where they undergo various treatments (extraction, amplification, passage through a thermal cycler, etc.). There are also rapid self-tests with which we obtain the result thanks to a strip that changes color. But like the DNA structure
DNA is a very long molecule, composed of a succession of nucleotides attached to each other by phosphodiester bonds. There are four … “data-image =” https://cdn.futura-sciences.com/buildsv6/images/midioriginal/e/6/5/e65f7c1212_95629_adn-definition.jpg “data-url =” https: / /www.futura-sciences.com/sante/definitions/medecine-adn-87/ “data-more =” Read more “>ADN is not amplified, they are less reliable and only detect viral loads high. Vittorio Saggiomo, a researcher in bionanotechnologies at the University of Wageningen in the Netherlands, therefore invented a method to detect the virus at home and in a safe way, using a simple pod of Nespresso coffee and a saucepan of ‘boiling water.
CoroNaspresso, DNA amplification for everyone
A device ” very inexpensive, easy to produce in millions of copies, universal and zero waste “, Boasts the researcher who describes his invention called CoroNaspresso on the pre-publication site ChemArxiv. The test relies on isothermal loop-mediated amplification (LAMP). The latter uses primers that recognize distinct regions of the target DNA. First, a DNA DNA polymerases
Les ADN polymérases catalysent…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/1/b/c/1bc6add11d_117115_polymerase-adn.jpg” data-url=”https://www.futura-sciences.com/sante/definitions/genetique-polymerase-231/” data-more=”Lire la suite”>polymerase move the strands, which initiates synthesis, then two of the primers form loop structures to facilitate subsequent rounds of amplification. The sample can then be subjected to a reagent which will indicate by fluorescence whether the test is positive or negative. This method therefore allows an amplification similar to the test RT-PCR but, unlike him, the temperature necessary for the amplification reaction is constant (around 65 ° C). It must nevertheless be very precisely controlled.
A result in 25 minutes flat
Rather than using an expensive The different types of thermostats
The thermostat can be of two types: passive, it allows to keep a given temperature for a limited time (this is the case for example of “Thermos”); … “data-image =” https: // cdn. futura-sciences.com/buildsv6/images/midioriginal/b/9/c/b9cf145485_50037630_honeywell-thermostat-02.jpg “data-url =” https://www.futura-sciences.com/maison/definitions/maison-thermostat -10937 / “data-more =” Read more “>thermostat Vittorio Saggiomo came up with the idea of using a phase change material. By absorbing heat Physicists qualify heat as thermal energy. In the international system, it is therefore measured in joules (J). The heat corresponds more precisely to a transfer … “data-image =” https://cdn.futura-sciences.com/buildsv6/images/midioriginal/7/3/5/735709801b_92578_chaleur.jpg “data-url =” https://www.futura-sciences.com/sciences/definitions/physique-chaleur-15898/ “data-more =” Read more “>heat As they melt, these materials help maintain a constant temperature. Luckily, the researcher found a paraffin called Rubitherm®, which melts exactly at the required temperature (65 ° C) and is very cheap (around 13 euros per kilo). All that remained was to find a heat-resistant container to insert this wax into. This is where Vittorio Saggiomo thought of a simple one Nespresso coffee machine capsule, made up of
Symbol: Al Atomic number: 13 Electrons per energy level: 2, 8, 3 Atomic mass: 26.98 uMost isotopes … “data-image =” https://cdn.futura-sciences.com/buildsv6/images/ midioriginal / 2 / f / c / 2fc0ec5ad5_50037559_268722347-0327d1d78b-o-02.jpg “data-url =” https://www.futura-sciences.com/sciences/definitions/chimie-aluminium-14515/ “data-more = “Read more”>aluminium with strong heat transfer power.
All that remained was to place the sample in the dish and immerse everything in a liter of boiling water for 25 minutes. Paraffin stabilizes the temperature which therefore remains constant during the DNA amplification phase. Once out of the bath, just observe the color of the tube (which contains a reagent whose color changes depending on the pH) to see if the test is positive (yellow) or negative (orange).
20 euro cents the test!
The researcher tested the device on six members of his team and successfully detected the three cases of Covid. In the end, the test is barely 20 euro cents, against more than 70 euros for a test PCR or 10 euros for a quick test. Great savings in prospect for Social Security! ” The capsules are reusable, do not produce any waste and it is even possible to prepare a large number of them in advance to store them for months or even years at room temperature. », Assures Vittorio Saggiomo.
The only problem: do not confuse the test capsule with a real Nespresso capsule when you want to prepare a coffee. The researcher did not verify if the test tasted good.
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