• 대한의용생체공학회:의공학회지
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• 제27권6호
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• pp.418-426
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• 2006

In the artificial heart application, productivity and hemodynamic properties of artificial heart valves are crucial in successiful application to long term in vivo trials. This paper is about manufacture and assessment of trileaflet polymer heart valves using vacuum forming process(VFP). The VFP has many advantages such as reduced fabrication time, reproducibility due to relatively easy and simple process for manufacturing. Prior to VFP of trileaflet polymer heart valves, polyurethane(Pellethane 2363 80AE, Dow Chemical) sheet was prepared by extrusion. The sheets were heated and formed to mold shape by vacuum pressure. The vacuum formed trileaflet polymer heart valves fabrication is composed of two step method, first, leaflet forming and second, conduit forming. This two-step forming process made the leaflet-conduit bonding stable with any organic solvents. Hydrodynamic properties and hemocompatibility of the vacuum formed trileaflet polymer heart valves was compared with sorin bicarbon bileaflet heart valve. The percent effective orifice area of vacuum formed trileaflet polymer heart valves was inferior to bileaflet heart valve, but the increase of plasma free hemoglobin level which reflect blood damage was superior in vacuum formed trileaflet polymer heart valves Vacuum formed trileaflet polymer heart valves has high productivity, and superior hemodynamic property than bileaflet heart valves. Low manufacturing cost and blood compatible trileaflet polymer heart valves shows the advantages of vacuum forming process, and these results give feasibility in in vivo animal trials in near future, and the clinical artificial heart development program.

• 대한의생명과학회지
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• 제20권3호
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• pp.180-184
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• 2014

Mitochondria play a crucial role in many essential biological events by way of the electron transport chains and intermembrane proteins that they contain. Abnormalities in the mitochondria are strongly correlated with the development of diseases such as atherosclerosis, cancer, and diabetes. However, the study of mitochondria has been referred to as 'labor-intensive' because of the difficulty in isolating the organelles from their various sources, which can include cultured cells and tissues. Multiple companies provide mitochondria isolation kits, and it is possible for investigators to use different kits and apply different protocols depending on the source of the mitochondria. Therefore, we focused on producing an isolation buffer that could be applied to both cultured cells and tissues, and optimized an isolation protocol that could be used with both. Specifically, we adjusted the buffer condition that can be applied to human cervical cancer cells, fibroblasts, and tissues such as mouse liver and spleen. We also optimized the protocol to improve the efficacy and efficiency of the steps involved in the isolation of mitochondria. These methodological improvements may contribute to advanced research by allowing investigators to overcome the difficulties involved in isolation of mitochondria from biological samples.

• 폴리머
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• 제30권1호
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• pp.1-9
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• 2006

생체의료용 기능성 고분자재료의 개발에 관한 연구를 고분자의 기능성, 생체적합성 및 생분해성을 토대로 다루었다. 본 연구실에서 합성한 기능성 생분해 고분자들을 비롯하여 생분해성 고분자 생체재료, 온도 감응성 고분자재료, 양이온성 고분자재료, 비축합성 고분자 생체재료, 조직공학을 위한 생체고분자 DNA 매트릭스 및 RNAi 기법을 위한 고분자 등의 기능성 고분자 생체재료에 관련된 연구들을 정리하고, 가까운 장래에 의료용으로 이용될 수 있는 기능성 생체고분자에 대한 연구들을 제안하였다.

• Journal of Microbiology and Biotechnology
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• 제21권11호
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• pp.1193-1198
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• 2011

Encapsulation of biological material in the permiselective membrane allows to construct a system separating cells from their products, which may find biotechnological as well as biomedical applications in biological processes regulation. Application of a permiselective membrane allows avoiding an attack of the implanted microorganisms on the host. Our aim was to evaluate the performance of Bacillus subtilis encapsulated in an elaborate membrane system producing listeriolysin O, a cytolysin from Listeria monocytogenes, with chosen eukaryotic cells for future application in anticancer treatment. The system of encapsulating in membrane live Bacillus subtilis BR1-S secreting listeriolysin O was proven to exert the effective cytotoxic activity on eukaryotic cells. Interestingly, listeriolysin O showed selective cytotoxic activity on eukaryotic cells: more human leukemia Jurkat T cells were killed than human chronic lymphocytic B cells leukemia at similar conditions in vitro. This system of encapsulated B. subtilis, continuously releasing bacterial products, may affect selectively different types of cells and may have future application in local anticancer treatment.

• 대한의생명과학회지
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• 제7권1호
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• pp.47-51
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• 2001

To investigate an effect of the topical toluene application to .at skin on the liver injury, toluene (35 mg/$cm^2$) was sequentially applied for 3 or 5 days to rat skin and then the animals were sacrificed. 5 day toluene-treated rats showed the slight increase of live. weight per body weight(%) compared with control. Serum levels of xanthine oxidase and alanine aminotransferase activity were significantly increased both in 3 days and 5 days toluene-treated animals compared with control. In the histopathological findings, cytoplasmic degeneration of hepatocytes around the central vein was noted in the liver of rats applied with toluene to the skin. These results indicate toluene application to rat skin feds to somewhat slight liver injury. On the other hand, the hepatic benzylalcohol or aldehyde dehydrogenase activities were significantly decreased by toluene application to rat skin. In conclusion, the liver min was induced by toluene application to rat skin, and it can be hypothesized that accumulation of benzaldehyde in liver cell may be responsible for liver injury.

• Food Science and Biotechnology
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• 제17권1호
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• pp.26-30
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• 2008

This study was conducted to identify the effect of chilling temperature (-3 and $6^{\circ}C$) and aging (1- and 7-day) on objective meat quality, collagen solubility, and free amino acids in pork (longissimus muscle of Yorkshire). Warner-Bratzler (WB)-shear force indicated that variation in chilling temperature had no detectable effect on meat tenderness and tenderization during the 7-day aging period. Among the 13 detected free amino acids, only 3 amino acids (histidine, valine, leucine) were significantly affected by the temperature treatment (p<0.05). Collagen solubility was significantly increased at $6^{\circ}C$ treatment (p<0.05). There was a significant linear relationship (r=0.67, p<0.05) between changes in free amino acids and WB-shear force during the 7-day aging period. These results confirmed that chilling conditions had significantly affected collagen solubility, and meat tenderization occurred in direct proportion to an increase in free amino acids.

• 대한의생명과학회지
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• 제21권1호
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• pp.40-49
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• 2015

Mesenchymal stem cells (MSCs) have the ability to self-renew and differentiate into multi-lineage cells, thus highlighting the feasibility of using umbilical cord blood-derived MSCs (UCB-MSCs) for cell-therapy and tissueengineering. However, the low numbers of UCB-MSC derived from clinical samples requires that an ex vivo expansion step be implemented. As most stem cells reside in low oxygen tension environments (i.e., hypoxia), we cultured the UCBMSCs under 3% $O_2$ or 21% $O_2$ and the following parameters were examined: proliferation, senescence, differentiation and stem cell specific gene expression. UCB-MSCs cultured under hypoxic conditions expanded to significantly higher levels and showed less senescence compared to UCB-MSCs cultured under normoxic conditions. In regards to differentiation potential, UCB-MSCs cultured under hypoxic and normoxic conditions both underwent similar levels of osteogenesis as determined by ALP and von Kossa assay. Furthermore, UCB-MSCs cultured under hypoxic conditions exhibited higher expression of OCT4, NANOG and SOX2 genes. Moreover, cells expanded under hypoxia maintained a stem cell immnunophenotype as determined by flow cytometry. These results demonstrate that the expansion of human UCB-MSCs under a low oxygen tension microenvironment significantly improved cell proliferation and differentiation. These results demonstrate that hypoxic culture can be rapidly and easily implemented into the clinical-scale expansion process in order to maximize UCB-MSCs yield for application in clinical settings and at the same time reduce culture time while maintaining cell product quality.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2005년도 2005 Annual Meeting & International Symposium
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• pp.258-260
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• 2005

• Clinical Endoscopy
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• 제56권1호
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• pp.53-54
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• 2023

• 대한의생명과학회지
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• 제29권4호
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• pp.344-354
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• 2023

This study emphasizes the importance of early diagnosis and response to COVID-19, leading to the development of a rapid diagnostic kit using quantum dots. The research focuses on finely tuning bioconjugation with quantum dots to enhance the accuracy and sensitivity of COVID-19 diagnosis. We have developed a COVID-19 rapid diagnostic kit that exhibits a sensitivity more than 50 times higher than existing COVID-19 diagnostic kits. Quantum dots enable the accurate detection of COVID-19 viral antigens even at low concentrations, providing a rapid response in the early stages of infection. The COVID-19 quantum dot diagnostic kit offers quick analysis time, utilizing the quantum properties of particles to swiftly measure COVID-19 infection for immediate response and isolation measures. Additionally, this diagnostic kit allows for multiple analyses with ease, as multiple quantum dots can detect various antigens and antibodies simultaneously in a single experiment. This efficiency enhances testing, reduces sample requirements, and lowers experimental costs. The application of this diagnostic technology is anticipated in the future for early diagnosis and monitoring of other infectious diseases.