Jaesung Park

Extracellular vesicles are released by various cell types, particularly tumor cells, and may be potential targets for blood-based cancer diagnosis. However, studies performed on blood-borne vesicles to date have been limited by lack of effective, standardized purification strategies. Using in situ prepared nanoporous membranes, we present a simple strategy employing a microfluidic filtration system to isolate vesicles from whole blood samples. This method can be applied to purify nano-sized part

An extracorporeal bioartificial liver device has the potential to provide temporary hepatic support for patients with liver failure. Our goal was to optimize the flow environment for the cultured hepatocytes in a flat-plate bioreactor, specifically focusing on oxygen delivery using high medium flow rates while reducing the detrimental effects of the resulting shear stresses. We used photolithographic techniques to fabricate microgrooves onto the underlying glass substrate. The microgrooves, perp

We propose a microfluidic system that generates nanovesicles (NVs) by slicing living cell membrane with microfabricated 500 nm-thick silicon nitride (SixNy) blades. Living cells were sliced by the blades while flowing through microchannels lined with the blades. Plasma membrane fragments sliced from the cells self-assembled into spherical NVs of ~100-300 nm in diameter. During self-assembly, the plasma membrane fragments enveloped exogenous materials (here, polystyrene latex beads) from the buff

Extracellular vesicles (EVs) are secreted nano-sized vesicles that contain cellular proteins, lipids, and nucleic acids. Although EVs are expected to be biologically diverse, current analyses cannot adequately characterize this diversity because most are ensemble methods that inevitably average out information from diverse EVs. Here we describe a single vesicle analysis, which directly visualizes marker expressions of individual EVs using a total internal-reflection microscopy and analyzes their

We present a simple and rapid method to isolate extracellular vesicles (EVs) by using a polyethylene glycol/dextran aqueous two-phase system (ATPS). This system isolated more than ~75% of melanoma-derived EVs from a mixture of EVs and serum proteins. To increase the purity of EVs, a batch procedure was combined as additional steps to remove protein contaminants, and removed more than ~95% of the protein contaminants. We also performed RT-PCR and western blotting to verify the diagnostic applicab

Extracellular vesicles (EVs) are nano-sized vesicles secreted by cells, having beneficial effects for various types of regenerative processes. Although EVs have shown promising effects as therapeutic agents, these effects are difficult to research due to the limitations of EV production. In this study, an EV production method based on a flat-plate bioreactor is introduced. The bioreactor produces approximately seven times more mesenchymal stem cell-derived EVs than static culture conditions. The

We demonstrate a fluorescence-based nanoparticle tracking analysis (NTA) system for the characterization of both the size and membrane protein expression of individual extracellular vesicles (EVs). A sheet of lasers with four different wavelengths was sequentially shone onto extracellular vesicles according to a preprogrammed schedule, providing scattering images intercalated by three fluorescent images. The presence of extracellular vesicles was tracked frame by frame from scattering images. Fl

Analyzing extracellular vesicles (EVs) is an attractive approach to diagnosis of prostate diagnosis. However, existing methods of EVs isolation have low efficiency, purity, and long process time, and therefore have low diagnostic ability. To solve these the problems, a two-phase system is adapted to isolate EVs from a patient's urine. Urine from 20 prostate cancer (PCA) patients and 10 benign prostate hyperplasia patients was used to quantify the EVs-isolation ability of an aqueous two-phase sys

Extracellular vesicles can enhance cell proliferation by stimulating signal transduction and delivering genetic materials, and thus may have applications in regenerative medicine and other therapeutic applications. The processes employed to isolate extracellular vesicles, however, are complex and achieve low yield. To overcome these obstacles, a large-scale, micropore device for generating extracellular vesicle-mimetic nanovesicles that have characteristics similar to those of extracellular vesi