Early cancer detection is crucial for survival. Many cancer screening methods and biopsies, though, require complex and invasive surgical procedures causing cancers to go undetected during the early stages. Exosomes, or cell-secreted nanoscale extracellular vesicles, contain biomarkers that indicate cancers and other diseases, and they are constantly circulating in all body fluids. While the body fluids that contain these biomarkers are easy to access, the exosomes themselves have been challenging to purify.
Currently, in order to separate and purify exosomes from body fluids, differences in physical properties like size and density are exploited. Separation methods include repeated ultracentrifugation and filtration, chromatography, and precipitation, all of which require more than 10 hours and a large sample volume. This makes them ineffective for point-of-care cancer diagnostics.
Dr. Leyla Esfandiari is a professor in Electrical and Biomedical Engineering at the University of Cincinnati; she has invented a device that makes point-of-care noninvasive cancer screening and biopsies possible. The device is a low-voltage, ultrasensitive and rapid dielectrophoretic tool that works with borosilicate nanopipettes. It isolates nanovesicles based on both size and surface charge. With the vesicles still intact, the device can characterize them by sensing their dielectric properties. This rapid exosome capture and characterization allows for effective liquid cancer biopsy, which can detect cancer noninvasively and, most importantly, early.