독특한 색 변화를 나타내는 polydiacetylene 집합체의 제조 및 센서로의 응용

학위논문(박사) - 한국과학기술원 : 생명화학공학과, 2016.2 ,[viii, 76 p. :]Amine-functionalized polydiacetylene demonstrated a specific color response to an aminoglycosidic anti-biotic such as neomycin. This phenomenon is very interesting because the presented system lacks any specif-ic interacting binding site and possesses only amine functional groups. The effect of functional groups in polydiacetylene system was characterized, and the substrate effects were also characterized for other amino-glycosidic antibiotics. The system consisting of amine-functionalized polydiacetylene and neomycin only showed the color change at a 10 $\mu$ M concentration of neomycinat 1 $\mu$ M of neomycin it could be detected using fluorescence. The results from zeta potential measurements and pH variations revealed color response to be the result of interaction between the vesicle and neomycin. The strength of the interaction depended on the number of amine functional groups in the polydiacetylene that are in contact with one neomycin mole-cule. In the next study the noble vesicular system of polydiacetylene showed a red shift by two kinds of detect-ing systems. One of the systems involves absorption of target materials from outer side of the vesicle, and the other system involves the permeation through the vesicular layers from within the vesicle. The chromatic mixed vesicles of N-(2-aminoethyl)pentacosa-10,12-diynamide (AEPCDA) and dimethyldioctadecylammo-nium chloride (DODAC) were fabricated by sonication, followed by polymerization by UV irradiation. The stability of monomeric vesicles was observed to increase with polymerization of the vesicles. Methotrexate was used as a target material. The polymerized mixed vesicles having a blue color were exposed to a concen-tration gradient of methotrexate, and a red shift was observed indicating the adsorption of methotrexate on the polydiacetylene bilayer. In order to check the chromatic change by the permeation of methotrexate, we separated the vesicle portion, which contained methotrexate inside the vesicle, and checked chromatic change during the permeation of methotrexate through the vesicle. The red shift apparently indicates the dis-turbance in the bilayer induced by the permeation of methotrexate. The maximum contrast of color ap-peared at the equal molar ratio of AEPCDA and DODAC, indicating that the formation of flexible and de-formable vesicular layers is important for red shift. Therefore, it is hypothesized that the system can be appli-cable for chromatic detection of the permeation of methotrexate through the polydiacetylene layer. In the next study the thermal chromatic sensitivity of polydiacetylenes (PDAs) with 10,12-pentacosadiynoic acid (PCDA) derivatives, which have a hydroxyl group (HEEPCDA) and an amine group (APPCDA), were investigated using $D_2O$ and $H_2O$ as solvents. The vesicle solution with polymerized HEEPCDA exhibited a reversible chromatic response during the heating and cooling cycle in $D_2O$, but not in $H_2O$. On the other hand, the vesicle solution with the polymerized APPCDA exhibited a reversible chromatic response in $H_2O$ during the heating and cooling cycle, but the color of the solution did not change much in $D_2O$. The critical vesicle con-centration of HEEPCDA was lower in $D_2O$ than in $H_2O$, and the chromatic sensitivity of the polymerized vesi-cles to temperature was slower in $D_2O$ than in $H_2O$. We think that it is due to $D_2O$ being a more highly struc-tured solvent than $H_2O$ with the hydrogen bonding in $D_2O$ stronger than that in $H_2O$.한국과학기술원 :생명화학공학과

분자가 각인된 자기 조립 단분자층의 감지 능력

학위논문(석사) - 한국과학기술원 : 생명화학공학과, 2012.2, [ vi, 46 p. ]한국과학기술원 : 생명화학공학과

Tat-aldose reductase prevents dopaminergic neuronal cell death by inhibiting oxidative stress and MAPK activation

Aldose reductase (AR) is known to detoxify aldehydes and prevent oxidative stress. Although AR exerts antioxidant effects, the role of AR in Parkinson's disease (Pd) remains unclear. The objective of the present study was to investigate the protective effects of AR protein against 1-methyl-4-phenylpyridinium (MP

Protective Role of Transduced Tat-Thioredoxin1 (Trx1) against Oxidative Stress-Induced Neuronal Cell Death via ASK1-MAPK Signal Pathway

Oxidative stress plays a crucial role in the development of neuronal disorders including brain ischemic injury. Thioredoxin 1 (Trx1), a 12 kDa oxidoreductase, has anti-oxidant and anti-apoptotic functions in various cells. It has been highly implicated in brain ischemic injury. However, the protective mechanism of Trx1 against hippocampal neuronal cell death is not identified yet. Using a cell permeable Tat-Trx1 protein, protective mechanism of Trx1 against hydrogen peroxide-induced cell death was examined using HT-22 cells and an ischemic animal model. Transduced Tat-Trx1 markedly inhibited intracellular ROS levels, DNA fragmentation, and cell death in H2O2-treatment HT-22 cells. Tat-Trx1 also significantly inhibited phosphorylation of ASK1 and MAPKs in signaling pathways of HT-22 cells. In addition, Tat-Trx1 regulated expression levels of Akt, NE-kappa B, and apoptosis related proteins. In an ischemia animal model, Tat-Trx1 markedly protected hippocampal neuronal cell death and reduced astrocytes and microglia activation. These findings indicate that transduced Tat-Trx1 might be a potential therapeutic agent for treating ischemic injury

Transduced Tat-PRAS40 prevents dopaminergic neuronal cell death through ROS inhibition and interaction with 14-3-sigma protein

Proline rich Akt substrate (PRAS40) is a component of mammalian target of rapamycin complex 1 (mTORC1) and activated mTORC1 plays important roles for cellular survival in response to oxidative stress. However, the roles of PRAS40 in dopaminergic neuronal cell death have not yet been examined. Here, we examined the roles of Tat-PRAS40 in MPP+- and MPTP-induced dopaminergic neuronal cell death. Our results showed that Tat-PRAS40 effectively transduced into SH-SY5Y cells and inhibited DNA damage, ROS generation, and apoptotic signaling in MPP+-induced SH-SY5Y cells. Further, these protective mechanisms of Tat-PRAS40 protein display through phosphorylation of Tat-PRAS40, Akt and direct interaction with 14-3-3 sigma protein, but not via the mTOR-dependent signaling pathway. In a Parkinson's disease animal model, Tat-PRAS40 transduced into dopaminergic neurons in mouse brain and significantly protected against dopaminergic cell death by phosphorylation of Tat-PRAS40, Akt and interaction with 14-3-3 sigma protein. In this study, we demonstrated for the first time that Tat-PRAS40 directly protects against dopaminergic neuronal cell death. These results indicate that Tat-PRAS40 may provide a useful therapeutic agent against oxidative stress-induced dopaminergic neuronal cell death, which causes diseases such as PD