A research team recently developed an extremely sensitive nanopore sensor that particularly identifies COVID-19 viruses and other human adenoviruses in an assortment of samples, including serum, saliva, or environmental specimens like wastewater.
A Nanowerk report specified that the said sensor combines two essential components, including a sensitive nanochannel and extremely specific DNA molecules attached to the channel surface.
The research teams said this method is as accurate as PCR tests, although simpler and faster in providing results that become available in less than two hours.
The membranes' fabrication technology using single nanopores has been developed for GSI Helmholtzzentrum für Schwerionenforschung for several years. Essentially, polymer films are irradiated with an individual high-energy heavy-ion projectile, like GeV gold ion, for example, at the UNILAC linear accelerator.
'Aptamers' DNA Fragments
As results published in Science Advances showed, as the ion passes through a polymer film, it produces a nanoscopic damage trail that's converted into an open nanochannel through chemical etching. The exact diameter, as well as the channel's shape, are adjusted by the etching parameters.
For this particular work, irregular nanopores with a tiny opening of below 50 nanometers were fabricated. The tiny size and the particular geometry guarantee a high level of sensitivity for transport procedures through the channel.
Furthermore, the sensor's selectivity is provided by an in-vitro process selection for DNA fragments known as aptamers integrated into the nanopore.
Such selective aptamer is not just able to identify the particular virus. It can differentiate as well the virus's ineffectiveness status.
GSI reported that Ana Sol Peinetti developed the applied aptamers during her work as a University of Illinois postdoctoral researcher.
GSI Nanopore Technology
Peinetti's familiarity with the GSI nanopore technology from her past stay in Omar Azzaroni's group at the Institute for Theoretical and Applied Physicochemical Research has led to her successful combination of both technologies.
According to the scientists, such an approach can determine infectious from the noncontagious viruses is an important innovation.
The widely used PCR tests detect viral genetic material, although they cannot determine whether a sample or a person is infectious.
The only tests which presently identify contagious viruses are plaque assays. They necessitate special preparation and days of incubation prior to providing results, while the new aptamer-nanopore sensor yields results within half an hour up to two hours and needs no pretreatment for the sample.
Reading out a virus's contagion status not just provides information on whether patients are infectious or not. It also offers a way to find out if specific inactivation strategies are effective.
Maria Eugenia Toimil-Morales, who'd led the ion-track nanotechnology group at GSI, said, Together with Azzaroni and Peinetti, they collaborate in a new project, where, according to the new sensor, the various virus activation protocols' effectiveness will be tested.
Great Protection Beyond the COVID-19 Pandemic
Nanopore-sensor technology has a great promise beyond this present pandemic. To identify other viruses, one needs to search for a pool of molecules that function as aptamers-new molecules for new viruses.
Peinetti explained that they even intend to achieve aptamers that distinguish between different SARS-CoV-2 variants, as explained in the Centers for Disease Control and Prevention site. In their research, they demonstrated the detection of contagious human adenoviruses, which are accountable for water-borne respiratory diseases globally.
Beyond the detection of viruses, the GSI nanopore technology is the basis of other options for the sensor. Many groups all over the world are creating particular functionalization tactics to impart selective uses to nanopore sensors.
Related information about COVID-19 detection through nanopore sequencing is shown on Oxford Nanopore Technology's YouTube video: