(Production: Pablo Cantudo)
Several decades ago, researchers Luis Blanco and Margarita Salas developed a tool that uses a viral enzyme (phage phi29 polymerase) to exponentially amplify very small amounts of genetic material. This technique is used today throughout the world and has very diverse applications in disciplines such as archeology or forensic medicine.
Today, a few months after the death of Margarita Salas, her colleague Luis Blanco, a researcher at the Higher Council for Scientific Research (CSIC), has embarked on an ambitious project that will apply this technique to fine-tune a genetic test to detect the coronavirus . The project has been funded by the Carlos III Health Institute and coordinated jointly by a team from the National Cancer Research Center led by Felipe Cortés, who has told us more details about this promising method in this interview.
“The basis is the same as that of PCR: it is about detecting the genetic material of the virus and amplifying it “, the researcher explains. “In this case we use the phage phi29 polymerase, which, unlike PCR, is capable of operating continuously at room temperature.”
“The idea is to use a specific probe that only activates when the SARS-CoV-2 genetic material is present. At that moment, there would be an exponential amplification by the polymerase, and thanks to this we will be able to detect the virus and confirm its presence in the sample ”, indicates Cortés.
Advantages: quick and easy to implement
Since phage phi29 polymerase is a very sensitive enzyme, the researchers hope to achieve a genetic test as accurate and reliable as that of PCR . “One of the problems of some of the tests that are being used now is their low reliability, we want to solve that with a rapid genetic test”, explains the scientist.
The main limitation of PCR is that it requires temperature cycles and, therefore, it is necessary to have very specific equipment and specialized personnel to perform this test. “One of the advantages of this test is that, since it can be performed at room temperature, it could be implemented in laboratories with minimal equipment such as health centers or even pharmacies, ” says Cortés. “The greatest limitation of PCR is that it requires centralizing the diagnosis and that greatly slows down decision-making.”
Phases of the project
Although there are good expectations, the researcher insists that it is necessary to validate the method well and verify that the technique is really effective in detecting the genetic material of the new coronavirus. “The biotechnological capacity of this enzyme is well proven, but it is necessary to test it specifically with SARS-CoV-2, with patient samples and under the conditions that would be optimal to implement it as a diagnostic test, ” explains Cortés.
“We have planned the study in three phases: the first would be to test it in ideal laboratory conditions to see if it really works,” explains the CNIO researcher. “In a second phase we would test it with patient samples, ideally with cases that have been positive, negative and doubtful with PCR . In this phase, the methodology will be validated and the level of sensitivity will be determined. The third phase will consist of developing a test prototype that can be taken to health centers and even pharmacies ”.
When would it be ready?
“If this were a normal project, the deadlines would be very different, but due to the current emergency situation we have set very tight times,” explains Cortés. “Ideally we would like to be able to have something for autumn, thinking about an eventual re-outbreak of the disease, but perhaps it is too optimistic. The rush in science is not good. The situation is dire, but you have to do things right ”, concludes the researcher.
