Browsing by Author "Thomas, Mallory M."

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Digital droplet RT-LAMP increases speed of SARS-CoV-2 viral RNA detection
(Wiley, 2024-06) Yuan, Yuan; Ellis, Perry; Tao, Ye; Bikos, Dimitri A.; Loveday, Emma K.; Thomas, Mallory M.; Wilking, James N.; Chang, Connie B.; Ye, Fangfu; Weitz, David A.
Nucleic acid amplification testing (NAAT) remains one of the most reliable methods for pathogen identification. However, conventional bulk NAATs may not be sufficiently fast or sensitive enough for the detection of clinically-relevant pathogens in point-of-care testing. Here, we have developed a digital droplet RT-LAMP (ddRT-LAMP) assay that rapidly and quantitatively detects the SARS-CoV-2 viral E gene in microfluidic drops. Droplet partitioning using ddRT-LAMP significantly accelerates detection times across a wide range of template concentrations compared to bulk RT-LAMP assays. We discover that a reduction in droplet diameter decreases assay times up to a certain size, upon which surface adsorption of the RT-LAMP polymerase reduces reaction efficiency. Optimization of drop size and polymerase concentration enables rapid, sensitive, and quantitative detection of the SARS-CoV-2 E gene in only 8 min. These results highlight the potential of ddRT-LAMP assays as an excellent platform for quantitative point-of-care testing.
Respiratory viruses: New frontiers—a Keystone Symposia report
(Wiley, 2023-02) Cable, Jennifer et al.; Thomas, Mallory M.
Respiratory viruses are a common cause of morbidity and mortality around the world. Viruses like influenza, RSV, and most recently SARS-CoV-2 can rapidly spread through a population, causing acute infection and, in vulnerable populations, severe or chronic disease. Developing effective treatment and prevention strategies often becomes a race against ever-evolving viruses that develop resistance, leaving therapy efficacy either short-lived or relevant for specific viral strains. On June 29 to July 2, 2022, researchers met for the Keystone symposium “Respiratory Viruses: New Frontiers.” Researchers presented new insights into viral biology and virus–host interactions to understand the mechanisms of disease and identify novel treatment and prevention approaches that are effective, durable, and broad.
Single-Cell Infection of Influenza A Virus Using Drop-Based Microfluidics
(American Society for Microbiology, 2022-10) Loveday, Emma Kate; Sanchez, Humberto S.; Thomas, Mallory M.; Chang, Connie B.
Drop-based microfluidics has revolutionized single-cell studies and can be applied toward analyzing tens of thousands to millions of single cells and their products contained within picoliter-sized drops. Drop-based microfluidics can shed insight into single-cell virology, enabling higher-resolution analysis of cellular and viral heterogeneity during viral infection. In this work, individual A549, MDCK, and siat7e cells were infected with influenza A virus (IAV) and encapsulated into 100-μm-size drops. Initial studies of uninfected cells encapsulated in drops demonstrated high cell viability and drop stability. Cell viability of uninfected cells in the drops remained above 75%, and the average drop radii changed by less than 3% following cell encapsulation and incubation over 24 h. Infection parameters were analyzed over 24 h from individually infected cells in drops. The number of IAV viral genomes and infectious viruses released from A549 and MDCK cells in drops was not significantly different from bulk infection as measured by reverse transcriptase quantitative PCR (RT-qPCR) and plaque assay. The application of drop-based microfluidics in this work expands the capacity to propagate IAV viruses and perform high-throughput analyses of individually infected cells.