4.7 Article

Microfluidic point-of-care device for detection of early strains and B.1.1.7 variant of SARS-CoV-2 virus

Journal

LAB ON A CHIP
Volume 22, Issue 7, Pages 1297-1309

Publisher

ROYAL SOC CHEMISTRY
DOI: 10.1039/d2lc00021k

Keywords

-

Funding

  1. Foxconn Interconnect Technology sponsored Center for Networked Intelligent Components and Environments (C-NICE) at the University of Illinois at Urbana-Champaign
  2. NSF Rapid Response Research (RAPID) [2028431]
  3. University of Illinois
  4. Carly Skadden of Carle Foundation Hospital (Urbana, IL) [20CRU3150]
  5. National Heart, Lung, and Blood Institute at the National Institutes of Health from UMass Medical School [3U54HL143541-02S2]
  6. Directorate For Engineering
  7. Div Of Electrical, Commun & Cyber Sys [2028431] Funding Source: National Science Foundation

Ask authors/readers for more resources

This study presents a microfluidic assay and device for rapid detection and differentiation of the Alpha variant and early strains of the SARS-CoV-2 virus in saliva samples. The detection assay utilizes isothermal RT-LAMP amplification and takes advantage of the S-gene target failure to distinguish between different variants using a binary detection system. Clinical sample testing confirms the high sensitivity and specificity of the developed point-of-care device.
Since the beginning of the COVID-19 pandemic, several mutations of the SARS-CoV-2 virus have emerged. Current gold standard detection methods for detecting the virus and its variants are based on PCR-based diagnostics using complex laboratory protocols and time-consuming steps, such as RNA isolation and purification, and thermal cycling. These steps limit the translation of technology to the point-of-care and limit accessibility to under-resourced regions. While PCR-based assays currently offer the possibility of multiplexed gene detection, and commercial products of single gene PCR and isothermal LAMP at point-of-care are also now available, reports of isothermal assays at the point-of-care with detection of multiple genes are lacking. Here, we present a microfluidic assay and device to detect and differentiate the Alpha variant (B.1.1.7) from the SARS-CoV-2 virus early strains in saliva samples. The detection assay, which is based on isothermal RT-LAMP amplification, takes advantage of the S-gene target failure (SGTF) to differentiate the Alpha variant from the SARS-CoV-2 virus early strains using a binary detection system based on spatial separation of the primers specific to the N- and S-genes. We use additively manufactured plastic cartridges in a low-cost optical reader system to successfully detect the SARS-CoV-2 virus from saliva samples (positive amplification is detected with concentration >= 10 copies per mu L) within 30 min. We demonstrate that our platform can discriminate the B.1.1.7 variant (USA/CA_CDC_5574/2020 isolate) from SARS-CoV-2 negative samples, but also from the SARS-CoV-2 USA-WA1/2020 isolate. The reliability of the developed point-of-care device was confirmed by testing 38 clinical saliva samples, including 20 samples positive for Alpha variant (sensitivity > 90%, specificity = 100%). This study highlights the current relevance of binary-based testing, as the new Omicron variant also exhibits S-gene target failure and could be tested by adapting the approach presented here.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.7
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available