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저주파진동의 미세유동에의 영향 관찰을 위한 실험적 접근
김진수(Jin Soo Kim),채기운(Ki Woon Chae),배진현(Jin Hyun Bae),정영훈(Young Hun Jeong),진송완(Songwan Jin) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
Recently, there have been various studies for fluidic behavior in micro-channel due to the rapid growth of biochip and MEMs applications. In this study, the fluidic behavior in micro-channel was investigated when low-frequency vibration was given to the micro-channel environment. Especially, an actuation using flexure mechanism and piezo-electric stack actuator was used to generate vibration up to 300 Hz, which was given to the micro-channel directly. The structural characteristics of the experimental setup were investigated to identify the vibratory behavior of the micro-channel. Consequently, the influence of the low-frequency vibration on the fluidic behavior in micro-channel could be observed.
산소 민감 발광 염료를 이용한 마이크로 채널 내에서 배양되는 세포 주변의 산소 농도 측정
이승열(SeungYoul Lee),진송완(Songwan Jin) 대한기계학회 2012 大韓機械學會論文集B Vol.36 No.5
본 논문에서는 산소 민감 발광 염료를 이용하여 마이크로 채널 내에서 세포가 배양되고 있을 때 산소농도를 측정하였다. 현재까지 알려진 여러 산소 민감 발광 염료 중 본 논문에서는 물에 잘 녹으며 장 시간 동안 사용하여도 독성이 없는 것으로 알려진 [Ru(bpy)3]<sup>2+</sup>를 사용하였으며 이와 더불어 산소 민감 염료 측정법의 단점을 보완하기 위하여 칼세인 염료를 이용하여 두 염료의 밝기 비율을 구하여 농도를 측정하였다. SCOMS 카메라와 마이크로 채널을 이용하여 캘리브레이션을 실시하고 농도와 밝기와의 관계를 구하였으며 이 관계를 이용하여 세포가 배양되는 조건에서의 배양액의 산소농도를 측정하였다. 실험 결과 채널입구에서 점점 멀어질수록 마이크로 채널 내에서 산소농도는 점점 낮아진다는 것을 관찰 할 수 있었다. In this study, we used an O<sub>2</sub>-sensitive luminescent dye to measure the O<sub>2</sub> concentration of culture media around HeLa cells cultured in a microchannel. [Ru(bpy)3]<sup>2+</sup>, which dissolves easily in water and which has no phototoxic effect, was used as the O<sub>2</sub>-sensitive dye. The ratiometric sensing method was applied by introducing calcein as the O<sub>2</sub>-insensitive dye, in order to overcome the disadvantages of intensity-based sensing. By performing calibration with an amperometric O<sub>2</sub> sensor, we could calculate the exact concentration of O<sub>2</sub> in the culture media. We applied this technique to measure the O<sub>2</sub> concentration around the cultured cells in the microchannel. As expected, the O<sub>2</sub> concentration gradually decreased as the cells moved farther away from the channel. This method is expected to be applicable to the investigation of hypoxia, which occurs commonly in scaffolds.
아가로스 겔에 포함된 세포의 농도가 확산 계수에 미치는 영향 측정
이병룡(Byung Ryong Lee),진송완(Songwan Jin) 한국가시화정보학회 2013 한국가시화정보학회지 Vol.11 No.1
In this study, diffusion coefficients of 20 kDa FITC-dextran in 2% agarose gel with different cell concentrations were measured using fiberoptic-based fluorescence recovery after photobleaching technique. As increasing cell concentration suspended in agarose gel, the diffusion coefficients were decreased. The diffusion coefficient of agarose gel which contains 10×106 cells/ml was decreased to 11% that of in agarose gel without cells. The distribution of fluorescence dye in 3D scaffold was also simulated. The simulation result shows that the diffusion coefficient is more significant factor than the scaffold structure.
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.
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.
마이크로 스케일 유동에서의 속도장 온도장 동시 측정 기법과 동전기 유동에의 적용
이범준(Beomjoon Lee),진송완(Songwan Jin),김영원(Young Won Kim),유정열(Jung Yul Yoo) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
In this paper, a technique of simultaneously measuring the velocity and the temperature in micro-scale flow is proposed. This method uses particle tracking velocimetry (PTV) for measuring the velocity and laser induced fluorescence (LIF) for measuring the temperature. To measure the accurate velocity and temperature, images for PTV and for LIF are separated by using two light sources and a shutter which is synchronized with a camera. By using only one camera, measurement system can be simplified and the error from complicate optical system can be minimized. Error analyses regarding the concentrations of fluorescent dye and particle and the light source fluctuation are also conducted. It is found that the error of the temperature and the velocity highly depends on the concentration of fluorescent particles which are used for PTV. This technique is applied to the simultaneous measurement of the velocity and the temperature in the electrokinetic flow. It is found that the velocity and temperature vary with the electric field strength and the concentration of electrolyte.
벽 근처에서 회전하는 박테리아 편모형 프로펠러 주변의 유동 가시화
조재형(JaeHyeong Cho),진송완(Songwan Jin) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
In this paper, flow field generated by rotating flagellar propeller near wall was visualizaed using particle image velocimetry technique. Macro scale model in high viscosity silicone oil was used to make low Reynolds number condition From the result, we could see that the center of rotating flow was shifted outward from the rotational axis of flagellar propeller.