Sensitive, smartphone-based SARS-CoV-2 detection from clinical saline gargle samples

Lane E. Breshears, Brandon T. Nguyen, Patarajarin Akarapipad, Katelyn Sosnowski, Kattika Kaarj, Grace Quirk, Jennifer L. Uhrlaub, Janko Nikolich-Žugich, Michael Worobey, Jeong Yeol Yoon

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Saliva specimens have drawn interest for diagnosing respiratory viral infections due to their ease of collection and decreased risk to healthcare providers. However, rapid and sensitive immunoassays have not yet been satisfactorily demonstrated for such specimens due to their viscosity and low viral loads. Using paper microfluidic chips and a smartphone-based fluorescence microscope, we developed a highly sensitive, low-cost immunofluorescence particulometric SARS-CoV-2 assay from clinical saline gargle samples. We demonstrated the limit of detection of 10 ag/μL. With easy-to-collect saline gargle samples, our clinical sensitivity, specificity, and accuracy were 100%, 86%, and 93%, respectively, for n = 27 human subjects with n = 13 RT-qPCR positives.

Original languageEnglish (US)
Article numberpgac028
JournalPNAS Nexus
Issue number1
StatePublished - Mar 1 2022


  • COVID-19
  • biosensor
  • clinical samples
  • immunoassay
  • microfluidics
  • point-of-care
  • smartphone
  • smartphone-based fluorescence microscope

ASJC Scopus subject areas

  • General


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