By Brian Owens
When the COVID-19 pandemic started Khashayar Ghandi, a materials chemist at the University of Guelph, had already been experimenting with using microwaves to kill bacteria and other pathogens. So he decided to see if the technique could work on the virus as well, either as a treatment or a disinfectant.
Ghandi and his colleagues used a microwave system they had developed to test the effect of electromagnetic radiation on the SARS-CoV-2 spike protein. They found that just four minutes of radiation, applied at body temperature, changed the conformation of the protein, denaturing it to criple the virus’ ability to infect host cells. Using heat to achieve the same effect takes an hour at 70-80 degrees Centigrade. The work was published recently in Scientific Reports.
It’s not yet clear how, exactly, the microwaves disrupt the proteins. “At this stage no one is 100% sure of that,” says Ghandi, but he does have some theories.
The microwaves may be acting on the differences in charge between different parts of the protein at sub-nanometer levels, he says, altering those charges leading to changes in the shape of the protein. Those changes in shape themselves could disrupt the protein’s activity, or the friction of that motion could also generate microscopic hot spots – hot enough to break chemical bonds, but on such a small scale that they do not affect the overall temperature of the protein.
Jean-Paul Jay-Gerin, a professor of nuclear medicine at the University of Sherbrooke, says the work shows the potential for using electromagnetic radiation as a disinfectant or therapeutic treatment. The fact that the technique works at body temperature is particularly promising, he says. “This suggests the system can be used for disinfection without damaging the material by high temperature,” he says. “As for treatment, the complete denaturation might not even be necessary since a modest disruption of the spike protein may be adequate to stop intrusion.”
Ghandi’s group has received a grant from the military to study how the technology could be used to disinfect surfaces and protective equipment, which has become the main focus of the research in recent months. But they are still experimenting with how microwaves could be used as a treatment. Working with researchers at the Ontario Veterinary College, Ghandi has shown that the same technique works against bovine coronaviruses, with no significant impact on immune cells. “We are working on making something that can be used not just for humans but also animals,” he says.
Ghandi envisions a couple of different potential treatment modes. One possibility is an endoscopic probe that could be inserted into the lungs to kill the virus at the source. The other is an MRI-like system that could treat an infection from outside the body.
Whether it is used for disinfecting surfaces or treating patients, Ghandi is pleased that the work he has devoted much of his career to is showing potential to have important real-world benefits. “This work started from curiosity, trying to solve fundamental questions in chemistry,” he says. “That led to a chain reaction all the way to applying the same technology to help with the pandemic.”