Evaluation of desialylation effect on zeta potential of extracellular vesicles secreted from human prostate cancer cells by on-chip microcapillary electrophoresis

Abstract

Extracellular vesicles including exosomes have the potential to be used in therapeutic and diagnostic applications. Towards the noninvasive diagnosis of prostate cancer using urinary exosomes, technical challenges lie in developing precise methods of analyzing exosomes. Previously, we developed an on-chip microcapillary electrophoresis (µCE) system equipped with a laser dark-field microscope. The zeta potential of exosomes of cancer cells was found to be larger than that of normal cells. In this study, the zeta potential of exosomes of normal and cancer prostate cells was evaluated using this system after treating with sialidase. The large negative charge of cancer exosomes was found to be due to the large amount of sialic acids. These results suggest that an on-chip µCE system is useful for the accurate evaluation of events that occur on the exosome surfaces at the single-particle level and promising for the prescreening of prostate cancer exosomes without the need for labeling.

Measurement of Individual Nanobioparticles on Microfluidic Chips by Laser Dark-field Imaging

“…2(a) [18,19]. Briefly, the platform comprises a microcapillary electrophoresis ( CE) chip, a pair of platinum electrodes, a DC power supply [Matsusada Precision HVL-1.1P(A)], a 404 nm laser source (Coherent Obis laser system, 50 mW), a microscope (Nikon, Ti-U), and a COMS camera (Andor Neo sCOMS).…”

“…Zeta potential of individual exosomes was evaluated by a procedure described previously [17][18][19]. Briefly, after of a sample chip, the chip was placed on the stage of an inverted microscope, and then electrodes were dipped into the reservoirs at both ends of the microchannel.…”

“…Recently, we have developed an on-chip microcapillary electrophoresis ( CE) platform equipped with a laser-dark field microscope that enables the zeta potential of individual nanobioparticles to be obtained [17][18][19]. Additionally, an analytical method for profiling the surface proteins of individual exosomes that employs the principle of on-chip particle immunoelectrophoresis has been proposed [19].…”

Microfluidic approaches for isolation, detection, and characterization of extracellular vesicles: Current status and future directions

“…The system composed of different compartments such as electrodes, power supply, a 488-nm laser source, an electron multiplying charge-coupled device (EM-CCD) camera, and an inverted microscope (Nikon Ti-U). Adapted with permission from ref (Akagi 2014). Copyright 2014, IOP Science.…”

Adsorption Phenomena of Anionic and Cationic Nanoliposomes on the Surface of Poly(dimethylsiloxane) Microchannel

“…This chip technology has been recognized as an important fundamental tool for NP characterization and multiparametric profiling of NPs, such as structure, size distribution, and zeta potential, within a single instrument [19,20]. Moreover, the potential difference between the medium and stationary layers of the fluid attached to the particle disperse in the medium represents the zeta potential, whereas the electroosmotic flow (EOF) is the electrolyte movement in an applied electric field in the fluid relative to a stationary charged surface [21,22].…”