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In JoVE (1)
Other Publications (7)
- The International Journal of Health Planning and Management
- Asia-Pacific Journal of Public Health / Asia-Pacific Academic Consortium for Public Health
- Biomedical Microdevices
- Lab on a Chip
- Lab on a Chip
- Bulletin of the World Health Organization
- Proceedings of the National Academy of Sciences of the United States of America
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Articles by Kidong Park in JoVE
JoVE Bioengineering
חרוזים ועל הפרדת תאים ריבוי ערוצים מכשירים microfluidic שימוש dielectrophoresis ו זרימה למינרית
1Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, 2Micro and Nanotechnology Lab, University of Illinois at Urbana-Champaign, 3Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 4Bioengineering, University of Illinois at Urbana-Champaign
Dielectrophoresis (DEP) היא שיטה יעילה לתפעל תאים. מעגלים מודפסים (PCB) יכול לספק אלקטרודות זול, לשימוש חוזר ויעיל מניפולציה מגע חופשי בתוך התא מכשירים microfluidic. על ידי שילוב של PDMS מבוססי ערוצי microfluidic עם coverslips על PCBs, אנחנו מדגימים מניפולציה חרוז תא הפרדה בתוך מכשירים microfluidic רב.
Other articles by Kidong Park on PubMed
Disease Coding Errors by Health Care Organizations: Effects of a Government Quality Intervention
Disease coding errors in claims data can cause serious problems for financing, reimbursement systems, public health surveillance and health research. This study analysed a government intervention to improve coding accuracy of health care organizations in South Korea. The intervention was implemented in 1997 by 226 organizations that had submitted erroneous claims in 1996 for five selected diseases. In 1998, 94% of these organizations eliminated coding errors for these diseases. Those organizations least responsive to the intervention were tertiary hospitals, those publicly owned, and those with other complex organizational characteristics. Overall, this simple intervention appeared extremely effective, and wider adoption of such techniques should be explored.
A Framework for Monitoring the Malaria Eradication Programme in Korea
The World Health Organisation established the Roll Back Malaria (RBM) strategy to reduce the global burden of malaria in 1998. A set of RBM indicators will not be suitable to the Republic of Korea due to the differences of the epidemiological and socio-cultural situation. Therefore, we have developed a framework and indicators for monitoring the outcomes and impact of the national malaria eradication programme that are appropriate for the situation in Korea. We reviewed the existing data in the national malaria eradication programme. We adopted general principles in developing a monitoring framework and indicators for monitoring RBM. Monitoring areas were recombined components and content that included the project plan, training health personnel, health education and public information, supply for manpower, equipment and materials, disease control, information system, supervision, community participation, intersectoral collaboration within practical guidelines for the national malaria eradication programme along with malaria control and RBM strategy of WHO. Twenty one monitoring areas were selected that identified critical areas for the national malaria eradication programme. Fifteen indicators of ten categories are proposed for use by the national malaria eradication programme in Korea.
Electrical Capture and Lysis of Vaccinia Virus Particles Using Silicon Nano-scale Probe Array
A probe array with nano-scale tips, integrated into a micro-fluidic channel was developed for the capture and lysing of small number of vaccinia virus particles using dielectrophoresis. The nano-scale probe array was fabricated in Silicon on Insulator (SOI) wafers, and sharpened with repeated oxidation steps. The gap between each probe ranged from 100 nm to 1.5 microm depending on fabrication parameters. The probe array was used to capture vaccinia virus using positive dielectrophoresis (DEP) from a flow within the microfluidic channel, and then the same probe array was used to apply high electric field to lyse the virus particles. It was shown that under electric field strengths of about 10(7)V/m, the permeability of ethidium bromide into the vaccinia virus particles was increased. Upon SEM analysis, the particles were found to be damaged and exhibited tubules networks, indicating disintegration of the virus outer layer. In addition, elongated strands of DNA were clearly observed on the chip surface after the application of the high electric field, demonstrating the possibility of electrical lysis of virus particles.
'Living Cantilever Arrays' for Characterization of Mass of Single Live Cells in Fluids
The size of a cell is a fundamental physiological property and is closely regulated by various environmental and genetic factors. Optical or confocal microscopy can be used to measure the dimensions of adherent cells, and Coulter counter or flow cytometry (forward scattering light intensity) can be used to estimate the volume of single cells in a flow. Although these methods could be used to obtain the mass of single live cells, no method suitable for directly measuring the mass of single adherent cells without detaching them from the surface is currently available. We report the design, fabrication, and testing of 'living cantilever arrays', an approach to measure the mass of single adherent live cells in fluid using silicon cantilever mass sensor. HeLa cells were injected into microfluidic channels with a linear array of functionalized silicon cantilevers and the cells were subsequently captured on the cantilevers with positive dielectrophoresis. The captured cells were then cultured on the cantilevers in a microfluidic environment and the resonant frequencies of the cantilevers were measured. The mass of a single HeLa cell was extracted from the resonance frequency shift of the cantilever and was found to be close to the mass value calculated from the cell density from the literature and the cell volume obtained from confocal microscopy. This approach can provide a new method for mass measurement of a single adherent cell in its physiological condition in a non-invasive manner, as well as optical observations of the same cell. We believe this technology would be very valuable for single cell time-course studies of adherent live cells.
Dielectrophoresis-based Cell Manipulation Using Electrodes on a Reusable Printed Circuit Board
Particle manipulation based on dielectrophoresis (DEP) can be a versatile and useful tool in lab-on-chip systems for a wide range of cell patterning and tissue engineering applications. Even though there are extensive reports on the use of DEP for cell patterning applications, the development of approaches that make DEP even more affordable and common place is still desirable. In this study, we present the use of interdigitated electrodes on a printed circuit board (PCB) that can be reused to manipulate and position HeLa cells and polystyrene particles over 100 microm thick glass cover slips using DEP. An open-well or a closed microfluidic channel, both made of PDMS, was placed on the glass coverslip, which was then placed directly over the PCB. An AC voltage was applied to the electrodes on the PCB to induce DEP on the particles through the thin glass coverslip. The HeLa cells patterned with DEP were subsequently grown to confirm the lack of any adverse affects from the electric fields. This alternative and reusable platform for DEP particle manipulation can provide a convenient and rapid method for prototyping a DEP-based lab-on-chip system, cost-sensitive lab-on-chip applications, and a wide range of tissue engineering applications.
Local Governments' Dependence on Tobacco Tax Revenue: a Deterrent to Tobacco Control in the Republic of Korea
To investigate, in the Republic of Korea, whether local governments' participation in an anti-smoking programme supported by the National Health Promotion Fund in 2002-2003 was related to the percentage of local tax revenue comprised by the tobacco consumption tax (TCT).
Measurement of Adherent Cell Mass and Growth
The characterization of physical properties of cells such as their mass and stiffness has been of great interest and can have profound implications in cell biology, tissue engineering, cancer, and disease research. For example, the direct dependence of cell growth rate on cell mass for individual adherent human cells can elucidate the mechanisms underlying cell cycle progression. Here we develop an array of micro-electro-mechanical systems (MEMS) resonant mass sensors that can be used to directly measure the biophysical properties, mass, and growth rate of single adherent cells. Unlike conventional cantilever mass sensors, our sensors retain a uniform mass sensitivity over the cell attachment surface. By measuring the frequency shift of the mass sensors with growing (soft) cells and fixed (stiff) cells, and through analytical modeling, we derive the Young's modulus of the unfixed cell and unravel the dependence of the cell mass measurement on cell stiffness. Finally, we grew individual cells on the mass sensors and measured their mass for 50+ hours. Our results demonstrate that adherent human colon epithelial cells have increased growth rates with a larger cell mass, and the average growth rate increases linearly with the cell mass, at 3.25%/hr. Our sensitive mass sensors with a position-independent mass sensitivity can be coupled with microscopy for simultaneous monitoring of cell growth and status, and provide an ideal method to study cell growth, cell cycle progression, differentiation, and apoptosis.
