Nanofluidics for Simultaneous Size and Charge Profiling of Extracellular Vesicles

Abstract

Extracellular vesicles (EVs) are cell-derived membrane structures that circulate in body fluids and show considerable potential for noninvasive diagnosis. EVs possess surface chemistries and encapsulated molecular cargo that reflect the physiological state of cells from which they originate, including the presence of disease. In order to fully harness the diagnostic potential of EVs, there is a critical need for technologies that can profile large EV populations without sacrificing single EV level detail by averaging over multiple EVs. Here we use a nanofluidic device with tunable confinement to trap EVs in a free-energy landscape that modulates vesicle dynamics in a manner dependent on EV size and charge. As proof-of-principle, we perform size and charge profiling of a population of EVs extracted from human glioblastoma astrocytoma (U373) and normal human astrocytoma (NHA) cell lines.

Characterization and modulation of surface charges to enhance extracellular vesicle isolation in plasma

“…This observation also matched with differential movements of EVs and LDLs seen in electrophoretic measurements 22 . At the physiological pH (7.4), the computed σ values were -3.6 mC/m 2 for (V)LDLs and -6.2 mC/m 2 for cancer EVs, whose values agreed with previous reports 23 , 24 . We also found that a slightly acidic pH maximizes the charge difference between EVs and (V)LDL ( Figure 2 C ).…”

“…Cancer EVs were most negatively charged. Symbols indicate σ values (pH 7.4) reported in other studies for EVs (◼) 24 and for LDLs (▲) 23 . (C) The estimated σ differences between EVs and (V)LDLs were plotted.…”

Characterizing interaction of multiple nanocavity confined plasmids in presence of large DNA model nucleoid

“…The device fabrication protocol is described in detail in ref. 18,19 and 27 To summarize, we use photolithography followed by reactive ion etching (RIE) to define the fluidic channel (the slit) on a borosilicate glass wafer. Electron beam lithography followed by RIE is then used to create the nanofluidic cavities.…”

MoS2-Plasmonic Nanocavities for Raman Spectra of Single Extracellular Vesicles Reveal Molecular Progression in Glioblastoma

“…Such approaches average over at least 10 EVs bound per bead or surface element. , A third wave of technologies has extended existing fluorescence-based single-cell and single-molecule analytical approaches to perform individualized EV analysis. Nano flow cytometry can now profile populations of 1000s of EVs down to 100 nm in size stained for a limited number of surface biomarkers. , Alternatively, single EVs can be surface immobilized and then exposed sequentially to a series of fluorescent antibody probes targeting specific markers, − achieving higher multiplexing and signal at the expense of throughput. This latter approach has been extended to the detection of EV-encapsulated RNA via fusing of surface bound EVs to liposomes containing molecular beacon probes that hybridize to given RNA/microRNA targets .…”