Dielectrophoresis Low and High Crossover Frequencies of Cancerous Exosomes.

Exosomes, which constitute a subclass of extracellular vesicles found in various body fluids, play a crucial role in intercellular communication. Exosomes consist of matter derived from their host, such as nucleic acids, proteins, and membrane proteins. Cancer cell-derived exosomes have cancer-specific molecules and are found in the body fluids. As such, they are highly useful in liquid biopsies for cancer diagnosis. For diagnosis, rapid and simple determination of the sampled exosomes is important. Dielectrophoresis (DEP) manipulation has the potential for use in liquid biopsies. DEP behavior based on variations in exosomes has not been well investigated. In this study, the dielectrophoretic characteristics of exosomes derived from four cancer cell lines were investigated: MCF-7, PC-3, HT-29, and COLO 201. The DEP crossover frequencies of these exosomes were determined by directly observing their DEP behaviors at various suspension medium conductivities. Each exosome type exhibited distinct dielectrophoretic characteristics, with significant differences in the lower crossover frequencies linked to variations in the membrane properties and inner conductivity. A single-shell dielectric model was used to estimate the dielectric and physical parameters of the exosomes, aligning with the experimental results. These findings highlight the potential of DEP for specific exosome separation, enabling rapid and simple exosome-based liquid biopsies for cancer diagnosis.