A few months after the death of Margarita Salas, the technology that this researcher helped to develop appears to be a promising tool for dealing with one of the great challenges posed by the new SARS-CoV-2 virus: being able to detect it quickly , simple and effective, especially in asymptomatic patients. A team made up of researchers from the Higher Council for Scientific Research (CSIC) and the National Center for Oncological Research (CNIO) has obtained funding from the Carlos III Health Institute to apply the DNA polymerase of the phi29 virus (phi29pol) in the early detection of the new virus. coronavirus.
Phage phi29 polymerase
One of Margarita Salas’s greatest contributions to science was this biotechnological tool that allows very small samples of genetic material to be amplified millions of times, facilitating their analysis. Phage phi29 polymerase is used throughout the world in disciplines such as archeology, forensics, and oncology.
“Its ability to amplify genetic material starting from a very small sample, even damaged, gives us the clue that it can be an extremely sensitive method to detect the presence of the genetic material of the virus , and therefore confirm the infection, even in those cases with a small viral load such as asymptomatic patients, ”says Felipe Cortés, head of the CNIO’s Topology and DNA Breaks Group and one of the coordinators of the new project.
Advantages over other detection methods
The current tests to detect the RNA of the new coronavirus are based on RT-PCR techniques that require highly specialized equipment and personnel. This greatly limits its ability to perform massive tests and obtain results in a short time , which is most desirable in order to take isolation measures in positive cases in time.
On the other hand, the alternatives based on the rapid detection of antibodies currently present important limitations in terms of their sensitivity and fidelity.
In the case of the polymerase of the phi29 virus, in addition to being capable of multiplying thousands or millions of times a sample of genetic material, its mechanism works even at room temperature, and it also allows the diagnosis of a large number of samples to be completed in less than one hour.
“This characteristic has also been key to developing the project, since it allows us to detect the virus at room temperature without the need to use specialized equipment or technical personnel,” adds Luis Blanco, Research Professor at the Severo Ochoa Molecular Biology Center (CBMSO ), joint center of the CSIC and the Autonomous University of Madrid and also coordinator of the new project.
Simple technology to diagnose at street level
The aim is to develop a portable device (similar to a pregnancy test) that allows the disease to be diagnosed easily, quickly and reliably, even at home. Likewise, this methodology will be adapted to detect the presence of the virus in the environment and on surfaces.
“This would allow us to diagnose at street level, even in primary care centers, nursing homes or other especially sensitive places, thus avoiding the sending of samples to trained laboratories, facilitating logistics and avoiding new infections”, they state researchers.
When will it be ready?
The Covid-19 diagnostic method proposed in the project is based on an improvement of the enzyme, developed by Miguel de Vega, CSIC researcher at CBMSO. The research is already underway, and in a first phase the sensitivity of the technique for the detection of the virus will be studied, including clinical samples from patients. The second phase will consist of an optimization of the system for its subsequent application in the clinic.
Those responsible for the project hope to have the first version ready by autumn, a time that could coincide with an eventual outbreak of the disease.
Image: 3D model of the chimeric variant of phi29 DNA polymerase called Qualify. Adapted from Vega et al, (2010) PNAS 107, 16506-11.
