杏吧原创

A magnetic-levitation device can sort viruses and bacteria that naturally float in the air, making them ready for further analysis.

A cubic metre of indoor air can contain hundreds of thousands of bacteria and viruses, but conventional devices for analysing which may be harmful can often take a long time or are not sensitive enough to pick up on particularly small viruses. at the University of British Columbia in Canada and her collaborators turned to magnetic levitation to see if it could make the process more effective.

Magnetic levitation is a method that uses magnetic forces to push objects upwards against gravity, making them float. The researchers wanted to take a sample of air and use this method to levitate different particles within it, like dust or viruses, into separate groups instead of being mixed.

They placed a magnet at the top and the bottom of a glass, which was filled with a solution of the metal gadolinium. Next, they injected a mixture of air and viruses or bacteria into the tube where they mixed with the gadolinium solution.

Instead of gravity making them all fall to the tube鈥檚 bottom, magnetic forces levitated these particles at different heights depending on their density. For instance, bacteria levitated closer to the tube鈥檚 bottom while viruses, which are less dense, levitated closer to its top.

Pakpour says the team knew that levitation would happen, but it was less clear whether the very small viruses would stay intact and active enough to then be extracted and analysed further. Testing their device with bacteriophage viruses 鈥� viruses that attack bacteria 鈥� and SARS-CoV-2 showed that not only is this possible, but that the magnetic levitation process also produced fairly pure samples of these objects.

鈥淐onventional approaches to isolate viable viruses require high skills and expensive equipment and it takes a long time to get results. This new approach seems to address the challenges well, at least in laboratory tests,鈥� says at the University of Miami in Florida. However, he says the method would work less well when it comes to separating different viruses that have a similar density.

The goal for Pakpour and her colleagues is to eventually turn it into a portable, automated device that anyone could use. She says the team is close to commercialising a similar device specifically for influenza viruses.