Rapid, sensitive detection of intact SARS-CoV-2 using DNA nets and a smartphone-linked fluorimeter

We report a single-step, room-temperature, 5-10 minute SARS-CoV-2 saliva self-monitoring method that overcomes the limitations of existing approaches through the use of fluorophore-releasing Designer DNA Nanostructures (DDNs) that bind with the multivalent pattern of spike proteins on the exterior intact virions and an inexpensive smartphone-linked, pocket-size fluorimeter, called a V-Pod for its resemblance to an Apple AirPod (TM) headphone case. We characterize the V-Pod fluorimeter performance and the DDN-based assay to demonstrate a clinically relevant detection limit of 10(4) virus particles/mL for pseudo-typed WT SARS-CoV-2 and 10(5) virus particles/mL for real pathogenic variants, including Delta, Omicron, and D614g.

Automated summary

We present a novel method for self-monitoring of SARS-CoV-2 in saliva, which involves the use of fluorophore-releasing Designer DNA Nanostructures (DDNs) that bind with spike proteins on the virus particles and a smartphone-linked, pocket-size fluorimeter called V-Pod. The method demonstrates a clinically relevant detection limit for different variants of the virus.