Sehyun Shin

Red blood cells (RBCs) exhibit a unique deformability, which enables them to change shape reversibly in response to an external force. The deformability of RBCs allows them to flow in microvessels while transporting oxygen and carbon dioxide. In this review, we discussed the major determinants of RBC deformability, which include cell geometry, internal viscosity, rheological properties of the membrane, osmotic pressure, calcium, nitric oxide, temperature, ageing, and depletion of adenosine triph

Erythrocyte deformability improves blood flow in the microvessels and in large arteries at high shear rate. The major determinants of RBC deformability include cell geometry, cell shape and internal viscosity (i.e., mean cell hemoglobin concentration and components of the erythrocyte membrane). The deformability is measured by several techniques but filtration of erythrocytes through micro-pore membranes and ektacytometry are two sensitive techniques to detect changes in erythrocytes under varie

The deformability of erythrocytes primarily depends on the composition of the membrane and cytoplasm, which consist of hemoglobin and other constituents. Current techniques that measure erythrocyte deformability often require labor-intensive and time-consuming measurement processes. This article describes a newly developed microfluidic ektacytometer (RheoScan-D) that adopts advanced microfluidic rheometry and conventional laser-diffraction technique to determine the deformability of erythrocytes

There has been an urgent need to quickly screen and isolate patients with viral infections from patients with similar symptoms at point-of-care. In this study, we introduce a new microfluidic method for detection of various viruses using rolling circle amplification (RCA) of pathogens on the surface of thousands of microbeads packed in microchannels. When a targeted pathogen meets the corresponding particular template, the DNAs are rapidly amplified into a specific dumbbell shape through the RCA

The erythrocyte deformability of blood samples, of diabetes mellitus (DM) patients with and without microangiopathic complications such as nephropathy and retinopathy, is determined and is compared with that of healthy control. The erythrocyte deformability is measured in terms of elongation index (EI) with microfluidic ektacytometer, which is very sensitive to detect changes in EI of erythrocytes due to hyperglycemic process. Each measurement of diffraction pattern of erythrocyte suspension in

The coronavirus disease 2019 (COVID-19) pandemic has been a major public health challenge in 2020. Early diagnosis of COVID-19 is the most effective method to control disease spread and prevent further mortality. As such, a high-precision and rapid yet economic assay method is urgently required. Herein, we propose an innovative method to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using isothermal amplification of nucleic acids on a mesh containing multiple microfluidic p

In the analysis of red blood cell (RBC) aggregation using optical detection, various shearing methods have been used to disperse RBCs in confined geometries. This study investigated RBC aggregation measurement in a microchip-stirring system by analysis of light transmission. A stirring-aided disaggregation mechanism in a microchip, consisting of a flat-cylindrical test chamber (D=4 mm, H=0.3 mm) and a magnetic stirrer (d=0.14 mm, l=2.2 mm), was used to generate a given shear which was large enou

The newly developed slit ektacytometer can measure RBC deformability with ease and accuracy. In addition, the slit ektacytometer can be easily used in a clinical setting owing to the incorporation of a disposable element that holds the blood sample.

Extracellular vesicles (EVs) are considered essential biomarkers in liquid biopsies. Despite intensive efforts aimed at employing EVs in a clinical setting, workable approaches are currently limited owing to the fact that EV-isolation technologies are still in a nascent stage. This study introduces a magnetic bead-based ion exchange platform for isolating EVs called ExoCAS-2 (exosome clustering and scattering). Owing to their negative charge, exosomes can easily adhere to magnetic beads coated w

Detailed analysis of red blood cells (RBCs) aggregation is often required in various clinical studies. Most conventional aggregation indices are dimensionless values and not available for comparison of across studies. Quite recently, we have developed microfluidic aggregometry that enables us to yield a critical shear-stress that are required to aggregate RBCs under the shearing hydrodynamic force. The present study investigated the relationships between the values of the critical shear-stress a

Glucose-rich plasma is commonly observed in diabetes mellitus and in-vitro incubation of erythrocytes in glucose-rich media may produce the non-enzymatic glycosylation of erythrocyte proteins. The present study investigates the effects of an increased concentration of glucose in a suspending medium on erythrocyte rheological parameters. Erythrocytes, which were obtained from ten healthy volunteers, were washed and incubated in vitro with glucose solutions at different concentrations and incubati

Tumor-derived extracellular vesicles (EVs) have become important biomarkers of liquid biopsies for precision medicine. However, the clinical application of EVs has been limited due to the lack of EV isolation practical technology applicable to clinical environments. Here, we report an innovative EV isolation method, which is quick and simple, and facilitates high-yield and high-purity EV isolation from blood. Introducing a cationic polymer in plasma resulted in rapid clustering of anionic EVs an