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Three-dimensional migration of neutrophils through an electrospun nanofibrous membrane.
Jin, Songwan,Park, Tae-Min,Kim, Cho-Hee,Kim, Jin-Soo,Le, Binh Duong,Jeong, Young Hun,Kwak, Jong-Young,Yoon, Sik Eaton Pub. Co 2015 Biotechniques Vol.58 No.6
<P>The study of immune cell migration is important for understanding the immune system network, which is associated with the response to foreign cells. Neutrophils act against foreign cells before any other immune cell, and they must be able to change shape and squeeze through narrow spaces in the extracellular matrix (ECM) during migration to sites of infection. Conventional in vitro migration assays are typically performed on two-dimensional substrates that fail to reproduce the three-dimensional (3-D) nature of the ECM. Here we present an in vitro method to simulate the 3-D migration of neutrophils using an electrospun nanofibrous membrane, which is similar to the ECM in terms of morphology. We examined the properties of neutrophil movement and the effects of gravity and the presence of IL-8, which has been widely used as a chemotactic attractant for neutrophils. The number of neutrophils passing through the nanofibrous membrane were higher, and their movement was more active in the presence of IL-8. Also, we confirmed that neutrophils could migrate against gravity toward IL-8 through a nanofibrous membrane.</P>
Jin, Songwan,Kim, Jae-Hun,Yun, Won-Soo Korean Society for Precision Engineering 2015 International Journal of Precision Engineering and Vol.16 No.10
Investigating the effects of various physical stimuli on cells is important for improving the efficiency of tissue repair and regeneration. In this research, we developed a dynamic well plate system by integrating the advantages of conventional well plates and a bioreactor to provide simultaneous physical stimuli of shear stress and a static magnetic field. The dynamic well plate involving perfusion of culture medium can control hydrodynamic shear while retaining the inherent simplicity of conventional well plates. The specific well plate cover was designed to load shear stress on cells during cultivation and was built to fit over a standard six-well plate. Additionally, to investigate the effects of a magnetic field on cell proliferation, a static neodymium magnet was placed beneath each well. To assess the system developed, calf pulmonary artery endothelial (CPAE) cells were cultured using the developed system. CPAE cells under hydrodynamic shear stress conditions were elongated and aligned in the direction of the flow and the magnetic field enhanced CPAE cell proliferation. Simultaneous application of a magnetic field and shear flow in CPAE cell cultivation allowed the development of optimized culture conditions, initially for cell proliferation and then for functional expression, such as cell shape changes.
[PD-0033] Digital Tools for Rice Genomics and Phenomics to Accelerate Breeding
Locedie Mansueto(Locedie Mansueto ),Lord Hendrix Barboza(Lord Hendrix Barboza ),Venice Juanillas(Venice Juanillas ),Jeffrey Detras(Jeffrey Detras ),Songwan Joun(Songwan Joun),Frances Nikki Borja(Franc 한국육종학회 2022 한국육종학회 공동학술발표집 Vol.2022 No.-
Flow Near the Meniscus of a Pressure-Driven Water Slug in Microchannels
Sungwook Kim,Songwan Jin,Jung Yul Yoo 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.5
Micro-PIV system with a high speed CCD camera is used to measure the flow field near the advancing meniscus of a water slug in microchannels. Image shifting technique combined with meniscus detecting technique is proposed to measure the relative velocity of the liquid near the meniscus in a moving reference frame. The proposed method is applied to an advancing front of a slug in microchannels with rectangular cross section. In the case of hydrophilic channel, strong flow from the center to the side wall along the meniscus occurs, while in the case of the hydrophobic channel, the fluid flows in the opposite direction. Further, the velocity near the side wall is higher than the center region velocity, exhibiting the characteristics of a strong shear-driven flow. This phenomenon is explained to be due to the existence of small gaps between the slug and the channel wall at each capillary corner so that the gas flows through the gaps inducing high shear on the slug surface. Simulation of the shape of a static droplet inside a cubic cell obtained by using the Surface Evolver program is supportive of the existence of the gap at the rectangular capillary corners. The flow fields in the circular capillary, in which no such gap exists, are also measured. The results show that a similar flow pattern to that of the hydrophilic rectangular capillary (i.e., center-to-wall flow) is always exhibited regardless of the wettability of the channel wall, which is also indicative of the validity of the above-mentioned assertion.
전반사형광현미경법과 타원체맞춤 방법을 이용한 고체벽면 근처에서의 3 차원 박테리아 경로 추적
구상모(Sangmo Koo),진송완(Songwan Jin),이용구(Yongkoo Lee),전호정(Hojeong Jeon),유정열(Jung Yul Yoo) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6
The motion of flagellated bacteria close to surfaces is relevant to understanding the early stage of Biofilm formation. When Bacterium cells are close to a surface, the cells often swim parallel to the surface in a circle for some time. The simplest and most effective way of understanding this motion is the individual cell tracking. In the present study, TIRFM is used to generate the evanescent wave near the surface so that it emits a green light due to eGFP gene transfection and illuminates a small specimen volume of about 100-㎚ depth. Also, using the PTV method, we can obtain the 3D motion data of bacteria near the surface. However, most of current 3D tracking methods, which are designed for spherical particles, is not optimized to track a bacteriumlike cell which is of a prolate ellipsoid. In this study, using the PTV method and proposing the ellipsoidal fitting to model the shape of bacteria realistically, we obtain the more accurate data of bacteria motion near the wall.
전반사 형광 이미지 분석을 통한 세포의 부착점 형성의 3차원 모델링
이용구(Yongkoo Lee),진송완(Songwan Jin),구상모(Sangmo Koo),전호정(Hojeong Jeon),유정열(Jung Yul Yoo) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6
We carried out a time-series analysis of images which were obtained while a living cell was forming its focal contact at the bottom of the gap between the cell and the substrate. In order to visualize the contact area selectively, we adopted total-internal-reflection-fluorescence (TIRF) method, which can illuminate specimen volume within only several hundred nano-meters above the substrate. From the fluorescent intensity of the TIRF image, we could calculate the distance of the cell surface from the substrate. As a result, we visualized the change of cell-contact type from the close-contact into focal-contact with information of its vertical displacement, and presented the three-dimensional evolution process of the cell-surface-profile near the contact area during this metamorphosis.
최충효(Choonghyo Choi),진송완(Songwan Jin),유정열(Jung Yul Yoo) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
Effects of cross-section geometry of capillary on the evaporation from the meniscus have been investigated by adopting several circular and rectangular capillaries. The evaporating meniscus shape, evaporation rate and flow near the evaporating meniscus of various liquids such as water, ethanol and methanol are determined. The shapes of water and ethanol menisci in circular capillary are quite different from each other due to the difference in surface tension. But the difference in meniscus shapes is relatively small in rectangular channel. The averaged evaporation fluxes in rectangular channel are much larger than that in circular capillary. The rotating vortex motion is observed near the evaporating menisci of ethanol and methanol except for the case of methanol in 200 × 20-㎛ capillary. The reason for these is considered to be the existence of the corner menisci at the four corners.