Low-cost Isolation and Ultrasensitive Detection of Extracellular Vesicles
Abstract: Extracellular vesicles (EVs), including exosomes and other membraneous vesicles, are abundantly secreted into the extracellular space by most cells from where they can ultimately accumulate in the circulation. EVs actively participate in diseaseinitiation, progression, and metastasis, shuttle signaling molecules (proteins and nucleic acids) that reflect their parental cell and tissue origins. However, translating EVs into clinical applications has been challenging due to the lack of 1) simple methods for EV analysis and 2) biomarkers that distinguish disease-related EVs from normal EVs. Here, we report two EV isolation methods called ExoTIC (exosome total isolation chip, Patent#:WO2017136430A1) and EV hunter (US Patent#: 62/593,128) which are simple, fast, cost-effective (as low as $1), and scalable, and provides high-yield isolation of EVs from cell culture media and a variety of bodily fluids (plasma, urine, lavage, cerebrospinal fluid, etc.). Then, we report a rapid, ultrasensitive and inexpensive nanoplasmon-enhanced scattering (nPES) assay that directly quantifies tumor-derived EVs from as little as 1 µL of plasma. We identified a pancreatic cancer EV biomarker, ephrin type-A receptor 2 (EphA2), and demonstrate that an nPES assay for EphA2-EVs distinguishes pancreatic cancer patients from pancreatitis patients and healthy subjects. These technologies have the potential to enable accelerated EV-based biomarker discovery and small molecular analysis that aresimple, reliable, and quantitative with broad applicability to diagnosis, prognostication, and treatment monitoring in patients with cancer and neurodegenerative diseases.