• 대한기계학회논문집A
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• 제32권10호
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• pp.831-835
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• 2008

We present a continuous electrical cell lysis chip, using a DC bias voltage to generate the focused high electric field for cell lysis as well as the electroosmotic flow for cell transport. The previous cell lysis chips apply an AC voltage between micro-gap electrodes for cell lysis and use pumps or valves for cell transport. The present DC chip generates high electrical field by reducing the width of the channel between a DC electrode pair, while the previous AC chips reducing the gap between an AC electrode pair. The present chip performs continuous cell pumping without using additional flow source, while the previous chips need additional pumps or valves for the discontinuous cell loading and unloading in the lysis chambers. The experimental study features an orifice whose width and length is 20 times narrower and 175 times shorter than the width and length of a microchannel. With an operational voltage of 50 V, the present chip generates high electric field strength of 1.2 kV/cm at the orifice to disrupt cells with 100% lysis rate of Red Blood Cells and low electric field strength of 60 V/cm at the microchannel to generate an electroosmotic flow of $30{\mu}m/s{\pm}9{\mu}m/s$. In conclusion, the present chip is capable of continuous self-pumping cell lysis at a low voltage; thus, it is suitable for a sample pretreatment component of a micro total analysis system or lab-on-a-chip.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.2137-2139
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• 2004

Cancer cell lysis at pulsed DC is realized using micromachined electrodes. In this research, quantitative analyses are performed on cell lysis results. The cell volume increasing at the pulses applied are analyzed in different medium conditions on osmotic pressure and conductivity, and the cell lysis procedures are studied in detail experimentally. Phosphate buffered saline (PBS) is used as the medium. To change the conductivity of PBS, NaCl concentration of PBS is adjusted, and inositol is used with PBS to control the effects of the osmotic pressure to cell lysis performance.

• Journal of Microbiology
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• 제45권6호
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• pp.593-596
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• 2007

In this study, we describe the development of a simple and efficient method for cell lysis via the insertion of a bacteriophage lambda lysis gene cluster into the pET22b expression vector in the following order; the T7 promoter, a gene for a target protein intended for production, Sam7 and R. This insertion of R and Sam7 into pET22b exerted no detrimental effects on cellular growth or the production of a target protein. The induction of the T7 promoter did not in itself result in the autolysis of cells in culture but the harvested cells were readily broken by freezing and thawing. We compared the efficiency of the cell lysis technique by freezing and thawing to that observed with sonication, and determined that both methods completely disintegrated the cells and released proteins into the solution. With our modification of pET22b, the lysis of cells became quite simple, efficient, and reliable. This strategy may prove useful for a broad variety of applications, particularly in experiments requiring extensive cell breakage, including library screening and culture condition exploration, in addition to protein purification.

• Mass Spectrometry Letters
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• 제11권2호
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• pp.36-40
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• 2020

Untargeted metabolomics is a useful tool for drug development focusing on novel chemotherapeutic and chemopreventative agents against cancer cells. In recent years, quadrupole time of flight liquid chromatography-mass spectrometry (Q-TOF LC/MS)-based untargeted metabolomic approaches have gained importance to evaluate the effect of these agents at the molecular level. The researchers working on cell culture studies still do not apply standardized methodologies on sample preparation for untargeted metabolomics approaches. In this study, the rough and wet lysis techniques performed on MCF-7 breast cancer cells were compared with each other via the Q-TOF LC/MS-based metabolomic approach. The C18 and hydrophilic interaction liquid chromatography (HILIC) columns were used for the separation of the metabolites in MCF-7 cell lysates. 505 peaks were detected through the HILIC column and 551 peaks were found through the C18 column for the wet lysis technique. This situation supported by the base peak chromatograms showed that the wet lysis technique allowed us to extract higher number of non-polar metabolites. Almost equal number of metabolites was found for the C18 and HILIC columns (697 peaks for the HILIC column and 695 peaks for the C18 column) when the rough lysis technique was used. However, the intensities of polar metabolites were higher for the rough lysis technique on base peak chromatograms for both the HILIC and C18 columns. Although cell lysis technique, which is the first step in the sample preparation for cell culture studies, does not cause dramatic differences in the number of the detected metabolite peaks, it affects the polar and non-polar metabolite ratio significantly. Therefore, it must be considered carefully especially for in vitro drug development studies.

• 대한기계학회논문집A
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• 제34권12호
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• pp.1785-1791
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• 2010

중합효소 연쇄반응(PCR)을 수행하려면 세포 용해(cell lysis)와 DNA추출(DNA purification)과정이 포함된 시료 전처리 과정을 거쳐야 한다. 종래의 시료 전처리 과정은 계면활성제와 같은 세포용해 버퍼를 이용하거나 열 또는 전기적 방법으로 세포막 파열을 유도하여 세포벽을 깬 후에 잔여물 처리과정을 거쳐 DNA를 추출하게 된다. 본 연구에서는 마이크로 비드와 PDMS 기둥을 이용한 필터가 있는 시료 전처리용 바이오칩을 설계 및 제작하였다. 또한 제작된 바이오칩을 사용하여 $80^{\circ}C$에서 2분간 세포용해를 수행하고 DNA를 추출하였다. 칩에서 전처리과정을 거친 시료내의 DNA농도와 순도를 측정하고 DNA PCR과 겔 전기영동을 통해 시료 전처리용 바이오칩의 성능을 평가하였다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권4호
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• pp.288-292
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• 2006

Through statistically designed experiments, lysis agents were optimized to effectively disrupt bacterial cells in a microfluidic device. Most surfactants caused the efficient lysis of Gram-positive microbes, but not of Gram-negative bacteria. A Plackett-Burman design was used to select the components that increase the efficiency of the lysis of the Gram-negative bacteria Escherichia coli. Using this experimental design, both lysozyme and benzalkonium chloride were shown to significantly increase the cell lysis efficiency, and ATP was extracted in proportion to the lysis efficiency. Benzalkonium chloride affected the cell membrane physically, while lysozyme destroyed the cell wall, and the amount of ATP extracted increased through the synergistic interaction of these two components. The two-factor response-surface design method was used to determine the optimum concentrations of lysozyme and benzalkonium chloride, which were found to be 202 and 99 ppm, respectively. The lysis effect was further verified by microscopic observations in the microchannels. These results indicate that Gram-negative cells can be lysed efficiently in a microfluidic device, thereby allowing the rapid detection of bacterial cells using a bioluminescence-based assay of the released ATP.

• 대한기계학회논문집A
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• 제32권10호
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• pp.844-849
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• 2008

We present a novel cell deformability monitoring chip based on the digitally measured cell lysis rate which is dependent on the areal strain of the cell membrane. This method offers simple cell deformability monitoring by automated high-throughput testing system. We suggest the filter design considering the areal strain imposed on the cell membrane passing through the filter array having gradually increased orifice length. In the experiment using erythrocytes, we characterized the cell deformability in terms of average fracture areal strain which was $0.24{\pm}0.014\;and\;0.21{\pm}0.002$ for normal and chemically treated erythrocytes, respectively. We also verified that the areal strain of 0.15 effectively discriminates the deformability difference of normal and chemically treated erythrocytes, which can be applied to the clinical situation. We compared the lysis rates and their difference for the samples from different donors and found that the present chips can be commonly used without any calibration process. The experimental results demonstrate the simple structure and high performance of the present cell deformability monitoring chips, applicable to simple and cost-effective cell aging process monitoring.

• 공업화학
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• 제9권6호
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• pp.857-863
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• 1998

Beer의 법칙을 이용하여 lysozyme-M. lysodeikticus cell의 용해반응속도 및 lysozyme의 활성을 측정할 수 있는 간단하고 새로운 실험방법을 제시하였다. M.lysodeikticus cell의 농도에 따라 용액의 UV 투과도를 측정하였으며 이것은 Beer의 법칙에 따르는 것으로 나타났다. 또한 용액 내의 lysozyme 농도 및 용해반응에 의해 생성되는 생성물은 UV 투과도에 전혀 영향을 미치지 않는 것으로 실험적으로 증명되었다. 따라서 lysozyme의 용해반응이 진행되는 동안 용액내에 존재하는 M. lysodeikticus cell의 농도는 UV-분광광도계를 이용하여 in-situ로 측정될 수 있었다. 이렇게 얻어진 M. lysodeikticus cell의 농도변화를 Michaelis-Menten식을 이용하여 lysozyme-M. lysodeikticus cell의 용해 반응속도 상수들을 결정하였다. 최대반응속도상수 $k_3$은 약 $0.1734sec^{-1}$로 나타났으며 Michaelis-Menten 상수는 약 $9.83{\times}10^{-6}M$으로 나타났다. Lysozyme의 용해반응속도가 활성에 의존하므로 이와 같은 측정을 통해 lysozyme의 활성도도 측정할 수 있었다.

• Childhood Kidney Diseases
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• 제21권1호
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• pp.31-34
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• 2017

Tumor lysis syndrome is a serious complication of malignancy, resulting from the massive and rapid release of cellular components into the blood. Generally, it occurs after initiation of chemotherapy. The onset of spontaneous tumor lysis syndrome (STLS) before anti-cancer treatment is rare and occurs mostly in Burkitt lymphoma and non-Hodgkin's lymphoma. There are only a few case reports in children. Here, we report a case of STLS secondary to T-cell acute lymphoblastic leukemia (ALL), which presented with urinary stone and subsequent acute kidney injury with severe hyperuricemia. Occult malignancy should be considered in case of unexplained acute kidney injury with extreme hyperuricemia.

• 한국식품영양학회지
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• 제3권1호
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• pp.23-28
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• 1990

Effect of lauric acid and whir derivatives on the growth of Bacillus subtilis var niger was studied. Lauric acid showed the strongest inhibition among the fatty acids tested, Lysis rate of lauric acid proved to be greatly sensitibility against logarithmic phase cells but was not so influenced by cell concentration. On the other hand, lauric acid was inhibited lysis activity when the pH shift from 7.0 to 5.5