• Toxicological Research
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• v.35 no.2
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• pp.161-165
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• 2019

Cysteamine has been used in cosmetics as an antioxidant, a hair straightening agent, and a hair waving agent. However, recent studies indicate that cysteamine can act as an allergen to hairdressers. The objective of this study was to develop and validate a simple and effective reversed-phase high-performance liquid chromatography (RP-HPLC) method for the measurement of cysteamine and its dimer, cystamine. Sodium 1-heptanesulfonate (NaHpSO) was used as an ion-pairing agent to improve chromatographic performance. Separation was performed on a Gemini C18 column ($250mm{\times}4.6mm$, $5{\mu}m$ particle size) using a mobile phase composed of 85:15 (v/v) 4 mM NaHpSO in 0.1% phosphoric acid:acetonitrile. UV absorbance was monitored at 215 nm. The RP-HPLC method developed in this study was validated for specificity, linearity, limit of detection, limit of quantitation, precision, accuracy, and recovery. Cysteamine and cystamine were chromatographically resolved from other reducing agents such as thioglycolic acid and cysteine. Extraction using water and chloroform resulted in the recovery for cysteamine and cystamine ranging from 100.2-102.7% and 90.6-98.7%, respectively. This validated RP-HPLC method would be useful for quality control and monitoring of cysteamine and cystamine in cosmetics.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2134-2136
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• 2004

A microcantilever-based biosensor with piezoresistor has been fabricated using surface micromachining technique, which is cost effective and simplifies a fabrication procedure. To evaluate the characteristics of the cantilever, the cystamine terminated with thiol was covalently immobilized on the gold-coated side of the cantilever and glutaraldehyde that would be bonded with amine group in the cystamine was injected subsequently. This process was characterized by measuring the deflection of the cantilever in real time monitoring. Using a piezoresistive read-out and a well-known optical beam deflection method as well carried out the measurement of deflection.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.1
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• pp.11-15
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• 2006

We propose an optical and an electrical detection methods for detecting various bio-molecules effectively with microcantilevers. The microcantilevers were fabricated employing surface micromachining technique that has attractive advantages in terms of cost efficiency, simplicity and ability of fabricating in array. The fluid cell system for injection of bio-molecular solution is fabricated using polydimethylsiloxane (PDMS) and a fused silica glass. The microcantilever is deflected with respect to the difference of the surface stress caused by the formation of self-assembled bio-molecules on the gold coated side of the microcantilever. It detected cystamine dihydrochloride and glutaraldehyde molecules and analyzed individual concentrations of the cystamine dihydrochloride solution. We confirm that the deflections of bending-up or bending-down are occurred by the bio-molecule adsorption and microcantilever can be widely used to a ${\mu}-TAS$ and a lab-on-a-chip for a potential detection of various bio-molecules.

• Journal of Microbiology and Biotechnology
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• v.16 no.10
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• pp.1523-1528
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• 2006

The optimization of a batch-type quartz crystal microbalance (QCM)-precipitation sensor measuring acetylcholinesterase (AChE) activity was conducted. To covalently bind AChE onto the gold electrode of a QCM surface, glutaraldehyde cross-linking to a cystamine self-assembled monolayer was tried at different cystamine concentrations. At the optimum conditions of the QCM-precipitation sensor, 0.1 M potassium phosphate buffer (pH 8.0), containing 0.01% Tween 80, was used as the reaction buffer, with the enzyme amount of 5 units for immobilization and the substrate concentration of 50 mg/ml. The current biosensor might find a future applicability to the sum parameter detection on organophosphorus and carbamate pesticides.

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.61-61
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• 2003

We have investigated the novel function of tissue transglutaminase (tTG) in the germinal vesicle breakdown (GVBD) of mouse oocyte. tTG was identified in ooplasm and germinal vesicle by immunostaining assay. Spontaneous maturation of the oocytes elevated in situ activity of tTG by over 2.5 fold at 3 hr, which was determined by a confocal microscopic assay. However, incubation with monodansylcadaverine (MDC), a tTG inhibitor, blocked the activation of tTG. The possible role of tTG in GVBD was investigated by the use of two tTG inhibitors, MDC and cystamine. MDC largely inhibited the GVBD by a concentration dependent manner. GV-stage oocytes were matured to the GVBD stage by 78% at 3 hr in BWW culture medium. However, in the oocytes incubated with MDC for 3 hr, the GVBD rates were 43 and 11% by 50 and 100 mM, respectively. MDC also blocked the entry of 70 kDa TRITC-dextran from the ooplasm to the compartment of germinal vesicle, indicating a possible inhibition of nuclear pore disassembly by MDC. The role of tTG in GVBD was further investigated by microinjection with cystamine. The control oocytes, injected with DPBS, showed about 80 % of GVBD at 3 hr. But the oocytes injected with cystamine showed 15% of GVBD at 3 hr and a little higher rate at 6 hr. In addition, the inhibition of GVBD maturation by MDC was reversible by washing. These results suggested that tTG was involved in the early event of mouse oocyte maturation

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2407-2409
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• 2005

본 논문에서는 다양한 생물분자 감지를 위한 센서로 마이크로캔틸레버를 제안하였고 이것을 이용해 여러 생물 분자들을 광학적, 전기적으로 분석하였다. 마이로캔틸레버는 표면 미세 가공 기술로 제작되었고, 이러한 제작 방식은 공정이 간단하고 비용이 적게 들며 센서 array가 가능하다는 장점을 갖는다. 생물분자를 포함하는 용액을 주입하기 위하여 PDMS와 fused silica glass를 이용해 fluid cell system을 제작하였다. 마이크로캔틸레버 상단의 gold가 코팅된 부분에서 생물분자의 자기조립 (self assembly)현상이 일어나고 이는 마이크로캔틸레버 상, 하단의 표면 스트레스 차이를 야기 시킨다. 이로 인해 마이크로캔틸레버 자체의 휘어짐 현상이 일어나게 되고 이러한 휘어진 정도를 측정함으로써 마이크로캔틸레버의 생물분자 감지능을 확인할 수 있었다. Cystamine dihydrochloride와 glutaraldehyde 분자를 분석하였고 각기 다른 농도의 cystamine dihydrochloride 용액에서도 실험함으로써 농도별 감지능 또한 확인하였다. 이러한 생물분자 감지를 위한 마이크로캔틸레버의 센서로써의 성능은 u-TAS 와 lab-on-a-chip에서 유용히 이용될 수 있으리라 확신한다.

• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.85.2-85.2
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• 2008

• Biomolecules & Therapeutics
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• v.22 no.3
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• pp.207-212
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• 2014

Skin hyperpigmentation is one of the most common skin disorders caused by abnormal melanogenesis. The mechanism and key factors at play are not fully understood. Previous reports have indicated that cystamine (CTM) inhibits melanin synthesis, though its molecular mechanism in melanogenesis remains unclear. In the present study, we investigated the effect of CTM on melanin production using ELISA reader and the expression of proteins involved in melanogenesis by Western blotting, and examined the involvement of transglutaminase-2 (Tgase-2) in SK-MEL-2 human melanoma cells by gene silencing. In the results, CTM dose-dependently suppressed melanin production and dendrite extension in a-MSH-induced melanogenesis of SK-MEL-2 human melanoma cells. CTM also suppressed a-MSH-induced chemotactic migration as well as the expressions of melanogenesis factors TRP-1, TRP-2 and MITF in a-MSH-treated SK-MEL-2 cells. Meanwhile, gene silencing of Tgase-2 suppressed dendrite extension and the expressions of TRP-1 and TRP-2 in a-MSH-treated SK-MEL-2 cells. Overall, these findings suggested that CTM suppresses a-MSH-induced melanogenesis via Tgase-2 inhibition and that therefore, Tgase-2 might be a new target in hyperpigmentation disorder therapy.

• Biomolecules & Therapeutics
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• v.21 no.3
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• pp.204-209
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• 2013

Osteoprotegerin (OPG) is a secreted glycoprotein and a member of the tumor necrosis factor receptor superfamily. It usually functions in bone remodeling, by inhibiting osteoclastogenesis through interaction with a receptor activator of the nuclear factor ${\kappa}B$ (RANKL). Transglutaminases-2 (Tgase-2) is a group of multifunctional enzymes that plays a role in cancer cell metastasis and bone formation. However, relationship between OPG and Tgase-2 is not studied. Therefore, we investigated the involvement of 12-O-Tetradecanoylphorbol 13-acetate in the expression of OPG in MG-63 osteosarcoma cells. Interleukin-$1{\beta}$ time-dependently induced OPG and Tgase-2 expression in cell lysates and media of the MG-63 cells by a Western blot. Additional 110 kda band was found in the media of MG-63 cells. 12-O-Tetradecanoylphorbol 13-acetate also induced OPG and Tgase-2 expression. However, an 110 kda band was not found in TPA-treated media of MG-63 cells. Cystamine, a Tgase-2 inhibitor, dose-dependently suppressed the expression of OPG in MG-63 cells. Gene silencing of Tgase-2 also significantly suppressed the expression of OPG in MG-63 cells. Next, we examined whether a band of 110 kda of OPG contains an isopeptide bond, an indication of Tgase-2 action, by monoclonal antibody specific for the isopeptide bond. However, we could not find the isopeptide bond at 110 kda but 77 kda, which is believed to be the band position of Tgase-2. This suggested that 110 kda is not the direct product of Tgase-2's action. All together, OPG and Tgase-2 is induced by IL-$1{\beta}$ or TPA in MG-63 cells and Tgase-2 is involved in OPG expression in MG-63 cells.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.703-706
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• 2000

We constructed a biospecific affinity surface using hyper-branched dendrimers on gold for biospecific recognition, and characterized the resulting surfaces by using confocal fluorescence microscopy. The dendrimer monolayer was firstly constructed on the mercaptoundecanoic acid SAM/Au with pentafluorophenyl ester activation and further functionalized with sulfo-NHS-biotin, an activated ester of biotin. To confirm the formation of biospecific affinity surface, FITC(fluorescein isothiocyanate)-labeled avidin was loaded onto the biotinylated dendrimer monolayer, and fluorescence images of the bound avidins were investigated with a confocal microscope. The constructed biospecific affinity surface showed a much more dense and uniform fluorescence compared to those from poly-L-lysine- and cystamine SAM-based affinity surfaces. For the dependency on the concentration of added FITC-labeled avidin on the affinity surface, derived fluorescence could be detectable from as low as $1{\mu}g/ml$, and intensified up to $50{\mu}g/ml$. Further reaction of FITC-labeled avidin layer with TMR(tetramethylrhodamine)-biocytins resulted in the efficient FRET(fluorescence resonance energy transfer) phenomenon. As an extension of the study, we attempted a patterning of the affinity surfaces on gold by microcontact printing. Fluorescence of the patterned surface demonstrated that FITC-labeled avidin molecules were specifically bound to the biotinylated patches.