(61h) Nanoplasmonic Quantification of Pathogen-Derived Extracellular Vesicles in Plasma Microsamples

Extracellular vesicles (EVs) are small membrane bound vesicles secreted by most cells and which circulate at high abundance. EVs function as carriers of genes, soluble factors and membrane-bound receptors/ligands from a parent cell/bacteria to local or distant cells, where EV uptake can alter the phenotype of the recipient cell. EVs are thus excellent candidates for biomarkers. EVs secreted by cancer cells can modulate alter the phenotype of adjacent and distant cells to promote tumor growth and metastasis. Our group has thus employed proteomics to analyze EVs derived from infected or cancerous cells to identify new diagnostic biomarkers. For example, we have used this approach to identify transmembrane proteins overexpressed on EVs derived from non-malignant versus malignant pancreatic and lung cell lines that can be utilized as biomarkers of pancreatic and lung cancer. Most current EV assays require an EV isolation step prior to analysis, which renders them impractical for most clinical applications. We have therefore developed nanoplasmonic near-field and far-field dark field microscopy assays that could directly analyze specific EV biomarker abundance from serum samples. We also developed an assay approach in which EVs directly captured from plasma are fused with reagent-loaded liposomes to sensitively amplify and detect a SARS-CoV-2 gene target. This approach accurately identified patients with COVID-19, including challenging cases missed by RT–qPCR.