SARS COV-2 detected with aptamers and ion track technology

Towards point-of-care diagnostics

© GSI Helmholtzzentrum für Schwerionenforschung GmbH / FAIR GmbH
ion track nanotechnology example
October 2021. Based on single-nanopore membranes of GSI, an interdisciplinary team of researchers from Darmstadt (DE), Urbana and Chicago, Il (US) and Buenos Aires (AR) developed a test method that detects SARS-CoV-2 in saliva, without sample pre-treatment. The sensor combines two key components: a sensitive nanochannel and highly specific DNA molecules attached to the channel surface. According to the research groups, the method is with the same sensitivity as a qPCR test, but simpler and faster providing results in less than two hours.

The technology for the fabrication of membranes with single nanopores has been developed at GSI over many years. Thin polymer films are irradiated with one individual high-energy heavy ion projectile (e.g. 1 GeV gold ion) at the linear accelerator UNILAC. As the ion passes through the film, it creates a nanoscopic damage trail that is converted into an open nanochannel by chemical etching. The precise diameter and the shape of the channel are adjusted by the etching parameters. For this work, asymmetric nanopores with a small opening of less than 50 nm were fabricated. The small size and the specific geometry ensure a particularly high level of sensitivity for transport processes through the channel.

© Ana Sol Peinetti 2021zoom
Nanopores coated with aptamers bind to viruses
The selectivity of the sensor is provided by an in-vitro selection process for DNA fragments, so-called aptamers, which are incorporated into the nanopore. These selective aptamers are not only able to recognize the specific virus but can also differentiate the infectivity status of the virus, in other words distinguish infectious from non-infectious corona viruses, which inventors say is crucial innovation.

GSI nanopore technology is the basis of other sensor options. Numerous groups around the world are developing specific functionalization strategies to impart selective functionalities to nanopore sensors. Nanopores in ion-track membranes are very versatile because they can be modified to respond to many different external changes, such as temperature, pH, light, voltage, or the presence of specific ion species, molecules, or drugs. GSI currently develops several highly sensitive sensor platforms and aims to integrate the functionalized nanopore membrane into a portable device for rapid and efficient virus detection and diagnosis.

Reference/s

Peinetti AS, Lake RJ, Cong W, Cooper L, Wu Y, Ma Y, Pawel GT, Toimil-Molares ME, Trautmann C,  (2021): Direct detection of human adenovirus or SARS-CoV-2 with ability to inform infectivity using DNA aptamer-nanopore sensors. Contributed: Azzaroni O, Mariñas B, Rong L. Science Advances, September 22: 1-12.

Source: GSI Helmholtzzentrum für Schwerionenforschung GmbH / FAIR GmbH

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