ABSTRACT
SARS-CoV-2 has mutated many times since the onset of the COVID-19 pandemic, and the omicron is currently the most dominant variant. Determining the specific strain of the virus is beneficial in providing proper care and containment of the disease. We have previously reported a novel method of counting the number of particle immunoagglutination on a paper microfluidic chip using a smartphone-based fluorescence microscope. A single-copy-level detection was demonstrated from clinical saline gargle samples. In this work, we further evaluated two different SARS-CoV-2 monoclonal antibodies to spike vs. nucleocapsid antigens for detecting omicron vs. delta and spike vs. nucleocapsid proteins. The SARS-CoV-2 monoclonal antibody to nucleocapsid proteins could distinguish omicron from delta variants and nucleocapsid from spike proteins. However, such distinction could not be found with the monoclonal antibody to spike proteins, despite the numerous mutations found in spike proteins among variants. This result may suggest a clue to the role of nucleocapsid proteins in recognizing different variants.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , COVID-19/diagnosis , Spike Glycoprotein, Coronavirus , Pandemics , Microfluidics , Antibodies, Viral , Nucleocapsid Proteins/genetics , Immunoassay , Antibodies, MonoclonalABSTRACT
Paper microfluidics has had a rich history in medical diagnostics owing to their portability, low-cost and capacity for mass manufacture. While nitrocellulose has widespread use in commercial paper-based assays, shortages can become a bottleneck for deployment. Here, we seek to overcome this limitation by enabling swift and efficient production of cellulose-based paper assays with minimal substrate processing via protein engineering. We demonstrate good clinical and lab-based performance for both serological and antigen rapid tests and their compatibility with roll-to-roll mass manufacturing, which validates our proposed workflow for commercialization. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.