Exosomes are cell-derived nanoscale (30-150 nm) vesicles found in body fluids. It has been reported that exosomes carry cell-of-origin specific nucleic acids, proteins and lipid molecules. Therefore, the potential of exosomes as biomarkers for disease detection has been intensively studied. Before any clinical usage of exosomes as biomarkers, in-depth characterization of exosomes, especially, analysis of inclusion molecules is essential. The majority of recent studies have focused on analyzing exosomal membrane proteins. In this study, we have utilized impedance spectroscopy (EIS) to analyze exosomes, which provides valuable information about the dielectric properties of exosomes. EIS is a label-free technique of characterizing samples suspended in a buffer solution. This study examined the magnitude and phase spectra of the exosomes produced by cultured non-cancerous (hTERT-HPNE) and cancerous (MIA PaCa-2) exosomes. EIS was measured using a microscale electrode device consisting of an FR4, a fiberglass laminate material for printed circuit boards, substrate with 10 ounces of copper, with 35 μm cladding. In addition, circuit models with constant phase element (CPE) for the exosome samples with electrodes were developed and analyzed to support our experimental findings. The results indicate that the impedance phase spectra can, in higher concentration samples, characterize samples using the magnitude and phase of the impedance.
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