• Tribology and Lubricants
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• v.21 no.5
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• pp.236-240
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• 2005

In order to prepare for the suitable surfaces of implants or medical devices, quantitative evaluation of adhesion between cells and biomaterials is essential. To better understand adhesion formation between cells and biomaterials, we used the cytodetachment technique which measures the adhesive force of a single cell through changing the, culture time and detachment speed. The results showed that the adhesive force could be affected by the culture time of cells on the surface of materials and the detachment speed. Moreover, there was a large discrepancy among the adhesion strength measured by similar techniques conducted on the different cells and substrates. It can be 'concluded that the variation of the force measurement technique can seriously alter the level of the force required to detach a cell on the surface of materials.

• Journal of Animal Reproduction and Biotechnology
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• v.38 no.3
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• pp.121-130
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• 2023

Background: Coating a culture plate with molecules that aid in cell adhesion is a technique widely used to produce animal cell cultures. Extracellular matrix (ECM) is known for its efficiency in promoting adhesion, survival, and proliferation of adherent cells. Gelatin, a cost-effective type of ECM, is widely used in animal cell cultures including feeder-free embryonic stem (ES) cells. However, the optimal concentration of gelatin is a point of debate among researchers, with no studies having established the optimal gelatin concentration. Methods: In this study, we coated plastic plates with gelatin in a concentration-dependent manner and assessed Young's modulus using atomic force microscopy (AFM) to investigate the microstructure of the surface of each plastic plate. The adhesion, proliferation, and differentiation of the ESCs were compared and analyzed revealing differences in surface microstructure dependent on coating concentration. Results: According to AFM analysis, there was a clear difference in the microstructure of the surface according to the presence or absence of the gelatin coating, and it was confirmed that there was no difference at a concentration of 0.5% or more. ES cell also confirmed the difference in cell adhesion, proliferation, and differentiation according to the presence or absence of gelatin coating, and also it showed no difference over the concentration of 0.5%. Conclusions: The optimum gelatin-coating for the maintenance and differentiation of ES cells is 0.5%, and the gelatin concentration-mediated microenvironment and ES cell signaling are closely correlated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1215-1220
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• 2004

Cell adhesion to any material surface is considered to be fundamental and important phenomenon in the fields of tissue engineering. Cell adhesion molecules, mechanism, and attachment force have been studied and described a lot. However, the effects of mechanical stimuli on the adhesive forces still have been left much to be investigated. In this study, to investigate the changes in cell adhesive force due to resting time period during the intermittent hydrostatic pressurizing (IHP), cells were cultured under the IHP with various resting times. Then the cell adhesive forces were measured quantitatively utilizing a cell detachment test system and immunofluorescent staining was performed using fluorescent microscopy. In the results, immediately after mechanical stimuli (150 minutes after seeding) and one hour later (210 minutes after seeding), the average adhesive force of experimental group 5 (resting time: 15min) compared with that of control group at same culture time was increased significantly (p<0.05). The results indicated that IHP can contribute in improving cell adhesive force and some of time intervals were required for the expression of cell response.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.598-598
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• 2013

The short lifetime of Proton Exchange Membrane Fuel Cell (PEMFC) is the one of the main problems to be solved for commercializing. Especially, the weak adhesion between metal nanoparticles and supports deteriorate the performances of nanocatalysts, therefore, it is considered to be a major failure mechanism. Using force-distance spectroscopy of atomic force microscopy (AFM), we characterized the adhesion between Pt nanoparticles and carbon supports that is crucially related to the durability for membrane fuel cell (MFC) electrode. In our study, force distance curves measured with Pt coated AFM cantilever, mimicking the behavior of corresponding nanoparticles on carbon supports, leads to the adhesion between metal nanoparticles and carbon supports. We found that theadhesion between Pt and HNO3-treated carbon is enhanced by a factor of 4, compared to Pt and bare carbon support, that is consistent with the macroscopic durability test of PEMFC. The higher adhesion between Pt and HNO3-treated carbon can be explained in light of the stronger chemical interaction by C/O functional groups.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.69-72
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• 2005

In this study, effects of IHPs with various resting times to cell adhesion were investigated through the measurements of cell adhesive force, number and area of focal contacts (stained vinculin spots), and projected cell area, perimeter and circularity. In addition correlation tests and curve estimations using the experimental results were performed fur the finding an essential factor for increment of cell adhesive force. Tn the results, immediately after mechanical stimuli (150 minutes after seeding) and one hour later (210 minutes after seeding), the average adhesive force of experimental group 5 (resting time: 15min) compared with that of control group at same culture time was increased significantly (p<0.05). Average projected area and perimeter of cells at Group 5 were increased significantly (p<0.05), while average circularity of cells at Group 5 incubated fur 210 minutes was decreased significantly (p<0.05). In the digital image analysis of focal contacts containing vinculins, area and numbers of focal contacts per cell at Group 5 were higher than those of the other groups. This study indicated that IHP with appropriate resting time could contribute in improving cell adhesive force, cell spreading, development of cytoskeleton and formation of focal contacts. And cell adhesive force was correlated to the morphological aspects of cell and development of focal contacts. Particularly, area of focal contacts was closely related to cell adhesive force.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.3
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• pp.140-150
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• 2007

A simple, label-free microfluidic cell purification method is presented for separation of cancer cells by exploiting difference in cell adhesion. To maximize the adhesion difference, three types of polymeric nanostructures (50nm pillars, 50nm perpendicular and 50nm parallel lines with respect to the direction of flow) were fabricated using UV-assisted capillary moulding and included inside a polydimethylsiloxane (PDMS) microfluidic channel bonded onto glass substrate. The adhesion force of human breast epithelial cells (MCF10A) and human breast carcinoma (MCF7) was measured independently by injecting each cell line into the microfluidic device followed by culture for a period of time (e.g., one, two, and three hours). Then, the cells bound to the floor of a microfluidic channel were detached by increasing the flow rate of medium in a stepwise fashion. It was found that the adhesion force of MCF10A was always higher than that of MCF cells regardless of culture time and surface nanotopography at all flow rates, resulting in a label-free detection and separation of cancer cells. For the cell types used in our study, the optimum separation was found for 2 hours culture on 50nm parallel line pattern followed by flow-induced detachment at a flow rate of $300{\mu}l/min$.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.362-366
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• 2004

Quantitative evaluation of substrates for cells is essential to understanding cell-material adhesive interaction and it is also necessary for the development of new biomaterials. Many cells on adhesive molecules will form an organization of actin into bundles and production of the large, highly organized structures termed focal adhesions. To better understand adhesion formations between cells and substrata, we have quantified the force required to displace attached cell. we allowed rabbit knee chondrocyte to attach on a substratum of microscope slide glass. Our results demonstrate that a force is required to detach cells is changed according to detachment time variation.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.2-5
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• 2011

This paper presents a numerical study on multiphase flows induced by wall adhesion The CSF(Continuum Surface Force} model is used for the calculation of the surface tension force and implemented in an in-house solution code(PowerCFD). The present method(code) employs an unstructured cell-centered method based on a conservative pressure-based finite-volume method with volume capturing method(CICSAM) in a volume of fluid(VOF) scheme for phase interface capturing As an application of the present method, the effects of wall adhesion are numerically simulated with the CSF model for a shallow pool of water located at the bottom of a cylindrical tank. Two different cases are computed, one in which the water wets the wall and one in which the water does not wet the wall. It is found that the present method simulates efficiently and accurately surface tension-dominant multiphase flows induced by wall adhesion.

• Journal of the Korean institute of surface engineering
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• v.42 no.5
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• pp.203-207
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• 2009

Interaction between human osteoblast (hFOB 1.19) and CrN films was conducted in vitro. CrN films were produced by cathodic arc plasma deposition. The surface was characterized by atomic force microscopy (AFM). CrN films, glass substrates and TiN films were cultured with human osteoblasts for 48 and 72 hours. Actin stress fiber patterns and cell adhesion of osteoblasts were found less organized and weak on CrN films compared to those on the glass substrates and the TiN films. Human osteoblasts also showed less proliferation and less distributed microtubule on CrN films compared to those on glass substrates and TiN films. Focal contact adhesion was not observed in the cells cultured on CrN films, whereas focal contact adhesion was observed well in the cells cultured on glass substrates and TiN films. As a result, the CrN film is a potential candidate as a surface coating to be used for implantable devices which requires minimal cellular adhesion.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.6
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• pp.30-36
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• 2014

Many different cells types have been found to be highly sensitive to mechanical force imposed by their surroundings. The cellular response to external mechanical forces has very important effects on numerous biological phenomena. In spite of its importance in biological processes, the cell adhesion force remains difficult to measure quantitatively at the cellular level. In this paper, to enhance quantitative measurements of cell adhesive interactions, a new attaching system and a method in which a glass bead can be attached to an AFM cantilever was designed and fabricated, and the degree of range displacement was controlled in the system. In an experiment, the movement of the stage in the attaching system and the attaching process were measured. The effectiveness of this system was confirmed as well in the experiment. In addition, through a commercial AFM system, the spring constant of the modified AFM probe could be measured.