• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.393-394
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• 2005

• Journal of the Korean Society of Visualization
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• v.18 no.3
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• pp.84-89
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• 2020

Cancer cells secrete angiogenic factors, and nearby vasculatures make new blood vessels essential for cancer development and metastasis in response to these soluble factors. Many efforts have been made to elucidate cancer-endothelial cell interactions in vitro. However, not much is known due to the lack of a suitable co-culture platform. Here, we introduce a 3D printing-based microfluidic system that mimics the in vivo-like cancer-endothelial cell interactions. The tumoroids and endothelial cells are co-cultured, physically separated by porous fibrin gel, allowing communication between two cell types through soluble factors. Using this microfluidic system, we were able to visualize new vessel formation induced by tumoroids of different origins, including liver, breast, and ovary. We confirmed that the ovarian tumoroids most induced angiogenesis while the other two cancer types suppressed it. Utilization of the proposed co-culture platform will help the researchers unveil the underlying mechanisms of the dynamic interplay between tumor and angiogenesis.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1700-1703
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• 2008

The purpose of this study was to examine the effects of various mechanical stimuli for MC3T3-E1 cells. Among the several mechanical stimulations, we focused on compressive stain and ultrasound. In this study, we developed a bioreactor capable of applying controlled stimuli to scaffolds. PLLA/PCL scaffold was fabricated by using salt-leaching method. We performed dynamic cell culture using preosteoblasts MC3T3-E1 cells with 1MHz, 30mW/cm2 ultrasound and 10% of compressive strain. Result of CCK-8 analysis at 1, 4, 7, 10 days showed that mechanical stimuli had no significant effect for cell proliferation. However, those stimuli influenced ALP(Alkaline phopatase) activity, which is one of differentiation marker.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.2
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• pp.103-108
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• 2005

For more accurately describing the durations of the light and the dark phases of micro-algal cells over the whole light-dark cycle, and probing into the relationship between the liquid circulation time or velocity, the aeration rate and cell density, a series of experiments was carried out in 10 cm light-path flat plate photobioreactors. The results indicated that the liquid flow in the flat plate photobioreactor could be described by liquid dynamic equations, and a high biomass output, higher content and productivity of arachidonic acid, $70.10\;gm^{-2}d^{-1},\;9.62\%$ and 510.3 mg/L, respectively, were obtained under the optimal culture conditions.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.5
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• pp.671-675
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• 2014

This paper presents a fabrication of hydrophilic Poly(dimethylsiloxane) (PDMS) with periodic wrinkling surface. The proposed periodic wrinkling surface was fabricated using the sequential processes of typical curing process of PDMS, cutting process, platinum deposition process, and wrinkling transfer process. The surface morphology of the fabricated wrinkling surface was observed by using optical and dynamic atomic force microscopy and discussed. The measured period and amplitude of wrinkling was about $2.2{\mu}m$ and $0.31{\mu}m$, respectively. And, the contact angles of water droplets on the wrinkled surface were measured in order to understand effect of the wrinkling surface on surface modification of hydrophobic PDMS. Our new finding was that the proposed wrinkling surface was hydrophilic and the measured contact angle was about $62^{\circ}$. Moreover, it was found out from the simple cell culture test that the fabricated wrinkling surface was more effective for cell spreading and adhesion than the case of native PDMS substrate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.3
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• pp.352-358
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• 2009

The physicochemical properties of dextran culture fermented by Leuconostoc citreum S5 were evaluated by the addition of various polysaccharides and heat-treatment. The consistency of dextran culture increased with the addition of carrot juice residue (CJR) in submerged culture, resulting in the highest consistency of 150 $Pa{\cdot}s^n$ and viable cell counts of $2.36{\times}10^9$ CFU/mL at 20% level of CJR. The dextran culture showed the pseudoplastic behavior and its consistency was greatly increased with the addition of various polysaccharides at 2% level. Addition of glucomannan indicated the highest consistency of 1275 $Pa{\cdot}s^n$ and their heat-treatment resulted in the increase of consistency except for glucomannan. After heat-treatment, the fermented dextran culture containing CJR fortified with gellan gum and carrageenan showed great change in rheology, indicating the highest consistency and hardness value resulted in the great increase of elastic and viscous moduli. The dynamic viscoelastic properties of dextran culture were greatly increased by the heat-treatment after fortification of various polysaccharides. Thus, the consistency and viable cell counts of dextran culture were increased with the addition of CJR. The rheological properties of dextran culture were manipulated by the fortification of various polysaccharides and heat-treatment.

• Journal of Microbiology and Biotechnology
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• v.22 no.3
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• pp.400-406
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• 2012

To improve the hydrogen yield from biological fermentation of organic wastewater, a co-culture system of dark- and photo-fermentation bacteria was investigated. In a pure-culture system of the dark-fermentation bacterium Clostridium butyricum, a pH of 6.25 was found to be optimal, resulting in a hydrogen production rate of 18.7 ml-$H_2/l/h$. On the other hand, the photosynthetic bacterium Rhodobacter sphaeroides could produce the most hydrogen at 1.81mol-$H_2/mol$-glucose at pH 7.0. The maximum specific growth rate of R. sphaeroides was determined to be 2.93 $h^{-1}$ when acetic acid was used as the carbon source, a result that was significantly higher than that obtained using either glucose or a mixture of volatile fatty acids (VFAs). Acetic acid best supported R. sphaeroides cell growth but not hydrogen production. In the co-culture system with glucose, hydrogen could be steadily produced without any lag phase. There were distinguishable inflection points in a plot of accumulated hydrogen over time, resulting from the dynamic production or consumption of VFAs by the interaction between the dark- and photo-fermentation bacteria. Lastly, the hydrogen production rate of a repeated fed-batch run was 15.9 ml-$H_2/l/h$, which was achievable in a sustainable manner.

• Biomedical Science Letters
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• v.13 no.4
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• pp.251-261
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• 2007

A myofiber of skeletal muscle is composed of myofibrils, sarcolemma (plasma membrane), and constameres, which anchor the myofibrils to the sarcolemma. Achvillin is a recently identified F-actin binding muscle protein, co-isolates with dystrophin and caveolin-3 in low-density sarcolemma of striated muscle, and colocalizes with dystrophin at costameres, the specialized adhesion sites in muscle. Archvillin also binds to nebulin and localizes at myofibrillar Z-discs, the lateral boundaries of the sarcomere in muscle. However other roles of archvillin on the dynamics of myofibrillogenesis remain to be defined. The goal of this study is, by using siRNA-mediated gene silencing technique, to investigate the effect of archvillin on the dynamics of myofibrillogenesis in cell culture of a mouse skeletal myogenic cell line (C2C12), where presumptive myoblasts withdraw from the cell cycle, fuse, undergo de novo myofibrillogenesis, and differentiate into mature myotubes. The roles of archvillin in the assembly and maintenance of myofibril and during the progression of myofibrillogenesis induced in skeletal myoblast following gene silencing in the cell culture were investigated. Fluorescence microscopy demonstrated that the distribution of archvillin was changed along the course of myofibril assembly with nebulin, vinculin and F-actin and then located at Z-lines with nebulin. Fluorescence microscopy demonstrated that knockdown of mouse archvillin expression led to an impaired assembly of new myofibrillar clusters and delayed fusion and myofibrillogenesis although the mouse archvillin siRNA did not affect those expressions of archvillin binding proteins, such as nebulin and F-actin. This result is corresponded with that of RT-PCR and western blots. When the perturbed archvillin was rescued by co-transfection with GFP or Red tagged human archvillin construct, the inhibited cell fusion and myotube formation was recovered. By using siRNA technique, archvillin was found to be involved in early stage of myofibrillogenesis. Therefore, the current data suggest the idea that archvillin plays critical roles on cell fusion and dynamic myofibril assembly.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.4
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• pp.492-499
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• 2009

A Silkie Bantam embryo fibroblast line (named SBF59 line) was successfully established by using direct explant culture and cryopreservation techniques. Cell morphology, viability, dynamic growth and contamination were tested and the karyotype and levels of isoenzymes of lactic dehydrogenase and malic dehydrogenase were analyzed. Four kinds of fluorescent protein extrogenes, including $pEGFP-N_3$, $pECFP-N_1$, $pEYFP-N_1$ and $pDsRed1-N_1$ were transfected into the cells. The results showed that the cells were healthy and possessed a fibrous structure without a change in morphology. The average viability of the cells was 96% before freezing and 90.5% after thawing. The growth curve appeared as typical "S" shape and the cell growth passed through a detention phase, a logarithmic phase and a platform phase; the estimated population doubling time (PDT) was 38.5 h; assays for the presence of bacteria, fungi, viruses and mycoplasmas were negative; the cell line showed no cross contamination when assessed by isoenzyme analysis; the chromosome number was 2n = 78 on more than 88% of occasions; four kinds of fluorescent protein extro-genes appeared to be expressed effectively with a high transfection efficiency between 18.3% and 42.3%. The cell line met the required quality control standard. It not only preserves the genetic resources of the important Silkie Bantam at the cellular level but also provides valuable materials for genomic, post-genomic, somatic cell cloning research and other applications.

• Journal of the Optical Society of Korea
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• v.18 no.2
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• pp.174-179
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• 2014

Since in vitro neural recording and imaging applications based on a surface plasmon resonance (SPR) technique have expanded dramatically in recent years, cytotoxicity assessment to ensure the biosafety and biocompatibility for those applications is crucial. Here, we report the cytotoxicity of the SPR substrate incorporating a flint glass whose refractive index is larger than that of a conventional crown glass. A high refractive index glass substrate is essential in neural signal detection due to the advantages such as high sensitivity and wide dynamic range. From experimental data using primary hippocampal neurons, it is found that a lead-based flint glass is not appropriate as a neural recording template although the neuron cells are not directly attached to the toxic glass. We also demonstrate that the adhesion layer between the glass substrate and the gold film plays an important role in achieving the substrate stability and the cell viability.