CBM2

Soper Gives Keynote Presentation at SelectBio Circulating Biomarkers 2021

Prof. Steven A. Soper, Director of CBM2, gave a keynote presentation February 26, 2021, at the SelectBio Circulating Biomarkers Digital Conference. His talk was titled, “Repurposing Microfluidic Tools for the Analysis of Liquid Biopsy Markers for COVID-19 Diagnostics.”

Prof. Steven A. Soper
Prof. Steven A. Soper

Extracellular vesicles (EVs), which are sub-micrometer sized particles produced from biological cells, can be isolated from liquid biopsy samples and used to manage a variety of diseases including the oncology-related diseases as well as others. However, disease-associated EVs must first be isolated in high purity to secure quality molecular data because even non-diseased cells produce EVs that can mask subtle disease-related molecular alterations. We have developed a plastic microfluidic chip, which is injection molded, consisting of 1.5M micropillars decorated with affinity agents to allow for selecting EVs from plasma. We have repurposed this chip to select SARS-CoV-2 virus particles (VPs) directly from saliva. In this presentation, Dr. Soper discussed an assay that can accept saliva samples and search for VPs (VP selection chip), and then count the number of VPs selected using a label-free approach; nano-Coulter Counter chip (nCC). The VP selection chip affinity targeted SARS-CoV-2 VPs using an aptamer surface immobilized to pillars contained within the chip that were directed against the SARS-CoV-2 Spike protein. The VP selection chip allowed for affinity loading up to 1010 SARS-CoV-2 VPs. Following selection (VP recovery >40%) and subsequent release (~89% efficiency) from the VP selection chip using a photocleavable linker and a blue-light LED, the selected particles were counted using the nCC chip. For high throughput VP counting, 5 nCCs were placed in parallel and offered 100% detection efficiency for VPs travelling through a 200 nm in-plane pore. The entire assay could be completed in ~20 min with full process automation. In addition, the selected particles were available for analysis of their RNA content using RT-qPCR. For a 20 sample set, RT-qPCR identified 4 samples of infected individuals and our assay was successful in identifying all 4 of those samples. The chips and controlling electronics could be packaged into a handheld instrument to allow for point-of-care testing or even at-home testing.