Researchers from the Catalan Institute of Nanoscience and Nanotechnology and other European centers will create a biosensor device to analyze the presence of the new coronavirus in patient samples in less than 30 minutes. The project called CoNVat uses the best diagnostic systems available, such as PCR testing and rapid testing.
European project VAT,by Catalan Institute of Nanoscience and Nanotechnology (ICN2) By researcher Laura Lettuce of CSIC, A new COVID-19 diagnosis system will be designed that will collect the best of various existing technologies.
Through a biosensor platform based on optical nanotechnology, it aims to diagnose diseases caused by the SARS-CoV-2 coronavirus accurately, quickly and without the need for complex equipment.
In this project, Two million euros The EU adopts a quick appeal for COVID-19 within the framework Horizon 2020,Cooperation University of Barcelona, This University of Aix-Marseille (France) and National Institute of Infectious Diseases (Italy).
Sensor technology includes Interference waveguide microchipAt present, it has the highest sensitivity to the diagnosis of clinical biomarkers.These microchips allow the detection and quantification of molecules or viruses in a single step without prior or subsequent amplification, so complete analysis can be performed In less than 30 minutes.
Combine the virus and identify its RNA
On the one hand, it will monitor the combination of viruses and sensors in real time through the following methods: Specific antibody Immobilized in the sensing surface (related to the antigen or protein of the pathogen), this will allow rapid diagnostic response and quantification of viral load in nasopharyngeal fluid, saliva or any other liquid samples of interest.
On the other hand, it will recognize ARN virus Use complementary DNA probes. This genomic assay does not require a PCR amplification process and allows several simultaneous tests on the same chip to distinguish the type of virus contained in the sample.
An illustration of a nanophotonic biosensor used to detect SARS-CoV-2. / ICN2
next to Hebron Valley Hospital At the University of Barcelona and Aix-Marseille, ICN2 has also begun to study the possibility of applying sensor technology to serological analysis (detection of antibodies in serum).
All in all, the idea is to develop a biosensor device for very fast analysis of intact coronavirus in patient samples. This system will enable it to distinguish it from other viruses (such as influenza) and to assess its viral load.
In the first year of the project, biosensors will be manufactured and used with real patients; in the second year, animals carrying the virus will be monitored in the laboratory.
The system tries to overcome some of the advantages of current tools (PCR and rapid antigen and serological testing), and makes full use of the advantages of each strategy, and tries to eliminate their disadvantages.
In fact, in parallel with the biosensor proposal, Nano Biosensor and Bioanalysis Application Group Researchers at ICN2 have prepared a study to review the different diagnostic methods that can be used for COVID-19.
this is report Provides an overview of conventional technologies used in clinical laboratories and new systems that are being developed and commercialized, which may be useful for population surveillance and rapid detection of SARS-CoV-2 virus and COVID-19 disease.
Three systems for diagnosing COVID-19
As reviewed in the ICN2 report, respiratory virus detection methods can be divided into three different strategies:
1. Detect the genetic material (RNA) of the virus by PCR
This is the most complex test, but due to the major investment in genome research to obtain the human genome in previous years, it has been developed the fastest. One of its steps is polymerase chain reaction (PCR).
This technology can induce genes to replicate as quickly as in nature. It needs time, precise and controllable temperature, and it needs to provide “food” for genetically correct reagents. In addition, there are only operations and commercial methods for copying human genes (DNA), so it is necessary to convert virus genes (RNA) into DNA before use.
One of the advantages of PCR technology is that it is established and commercialized by many companies. In view of the current technical level and a large number of different reagents, it can quickly adapt to new viruses within a few days. In addition, it can detect different viruses separately and even handle a very small amount of viruses very accurately.
One of its shortcomings is the need to use complex, precise and expensive instruments. For this, the samples must be concentrated in a laboratory with professional personnel. You must also know how to handle the samples reliably and follow the process very strictly, because in this The situation is sensitive and very susceptible to contamination. It will take a few more hours to get the results, plus the time required to ship the samples to the laboratory and return the results. All of these are relatively expensive.
There are several alternative technologies that can detect viral genes in other ways, but there are not enough technologies that can be deployed in hospitals and used for decision-making. In addition, many of these new technologies can only be used with musical instruments that are not currently mass-produced. Therefore, in order to reliably and operably detect viral genes at this time, only PCR technology exists.
2. Detect the virus as a single entity (antigen test)
In this case, the whole virus is detected by using antibodies designed to interact with molecules, which are the antigens (proteins) present in the virus coat, which are very specific and can be detected in principle.
The process of finding reagents is a difficult task. These reagents are actually similar to antibodies produced by patients that target specific proteins of the virus but not saliva, human cells, other normal bacteria, or other proteins present in other bacteria. virus. Since the current coronavirus is very similar to the virus we call SARS, some reagents have been developed for this occasion and are currently available.
These methods are based on the color change of reagents when they encounter viruses, which are due to reactions with their coat proteins. Therefore, a large amount of virus must be present in the sample to be effective. Since there is no amplification phase of several hours, these tests are fast and can produce results in minutes.
This is one of its undeniable advantages: it is a very fast technology that can be mass-produced at low cost. In addition, although you have to be careful when handling samples, it can replace samples to obtain results and does not require professionals. In principle, as long as there is a sufficient number of viruses, it will detect the disease from the first day.
However, it has encountered great difficulties: it requires a sufficient amount of virus in the sample, so it may be negative even in the presence of disease. In addition, the reagent must be very specific, so it is necessary to control the quality Test to ensure that the quality (reliability) is the same between batches.
3. Detection of antibodies in infected organisms (serological testing)
Once the infection begins, a sufficient number of antibodies will be produced for detection. In fact, usually, after overcoming the infection, the antibodies will remain for a period or a lifetime, which will confer immunity. This is the effect that the vaccine aims to achieve without spreading the disease.
Antibodies are found in the blood, especially serum, which is why they are called serological tests. To detect them, reagents containing parts similar to antigens are used, that is, contrary to other previous tests.
The execution of these tests is very simple, requiring only a small amount of blood samples to obtain results very quickly between 5 and 15 minutes. It is a technology that allows low-cost mass production. It is also portable, that is, no professional is required to obtain results on the sample site, and the results have been determined for other types of use or other viruses.
Its disadvantage is that a sufficient amount of antibodies is required in the sample, so it may be negative even when the disease is present, and the disease cannot be detected even at the beginning, because the antibody absorbs multiple antibodies. The number of days based on the person and his health.