Aptamer-capped nanoporous anodic alumina for SARS-CoV-2 spike protein detection

The COVID-19 pandemic, which began in 2019, has highlighted the importance of testing and tracking infected individuals as a means of mitigating the spread of the virus. In this context, the development of sensitive and rapid methods for the detection of SARS-CoV-2, the virus responsible for COVID-19, is crucial. Herein, a biosensor based on oligonucleotide-gated nanomaterials for the specific detection of SARS-CoV-2 spike protein is presented. The sensing system consists of a nanoporous anodic alumina disk loaded with the fluorescent indicator rhodamine B and capped with a DNA aptamer that selectively binds the SARS-CoV-2 spike protein. The system is initially evaluated using pseudotype virus systems based on vesicular stomatitis virus carrying different SARS-CoV-2 S-proteins on their surface. When the pseudotype virus is present, the cap of the solid is selectively removed, triggering the release of the dye from the pore voids to the medium. The nanodevice demonstrated its ability to detect pseudotype virus concentrations as low as 7.5·103 PFU mL. In addition, the nanodevice is tested on nasopharyngeal samples from individuals suspected of having COVID-19.