Browsing by Author "Chen, Tzu-Yin"

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Artificial peptide-controlled protein release of Zn2+-triggered, self-assembled histidine-tagged protein microparticle
(2020-03-01)
Chen, Tzu-Yin
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Cheng, Wan-Jung
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Horng, Jia-Cherng
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Hsu, Hsin-Yun
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交大名義發表
Protein microparticles have received attention as drug delivery systems because of their high protein stability and prolonged release in vivo. However, most current preparation processes introduce chemical crosslinkers, which often lead to protein inactivation and limit drug efficacy in delivery systems. In this study, we employed the well-known hexahistidine (His)-tag recombinant protein technology and a metal-triggerable collagen-mimetic peptide to enhance the binding strength between the protein and metal ion and fine-tuned the protein drug release. His-tagged proteins self-assembled to form microparticles (similar to 2 mu m) upon zinc ion treatment and sustained protein drug release was achieved in physiological saline. The results also indicated that by adjusting the peptide concentration and N- and C-terminal hexahistidine-tags, protein release could be controlled. Moreover, no protein denaturation was observed. We developed a universal strategy for facile protein microparticle fabrication under mild conditions and we demonstrated its potential as a therapeutics formulation with tunable protein release.
Comparative study on MoS2 and WS2 for electrocatalytic water splitting
(2013-09-19)
Chen, Tzu-Yin
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Chang, Yung-Huang
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Hsu, Chang-Lung
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Wei, Kung-Hwa
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Chiang, Chia-Ying
Replacing Pt by earth abundant catalysts is one of the most important tasks toward potential large-scale HER applications. Among many potential candidates, low cost and earth abundant transition metal dichalcogenides such as MoS2 and WS2 have been promising as good H-2 evolution electrocatalysts when they are engineered into the structures with active sites. In this work, we have performed systematic studies on the catalytic reactivity of both MoS2 and WS2 materials produced by one-step and scalable thermolysis from (NH4)(2)WS4 and (NH4)(2)MoS4 precursors respectively. Structural analysis shows that these materials prepared at a higher thermolysis temperature exhibit higher crystallinity. The H-2 evolution electrocatalysts efficiency for the MoS2 prepared at a lower temperature is higher than those at higher temperatures, where amorphous MoS2 or S-2(2-) species instead of crystalline MoS2 is the main active site. By contrast, crystalline WS2 prepared at high temperature is identified to be the key reaction site. Both catalysts display excellent efficiency and durability as an electrocatalyst operating in acidic electrolytes. This work provides fundamental insights for further design and preparation of emergent metal dichalcogenide catalysts, beneficial for the development in clean energy. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Enhancing the electrocatalytic water splitting efficiency for amorphous MoSx
(2014-03-26)
Hsu, Chang-Lung
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Chang, Yung-Huang
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Chen, Tzu-Yin
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Tseng, Chien-Chih
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Wei, Kung-Hwa
Amorphous molybdenum sulfide (MoSx) materials have been considered as cheap and promising catalysts for hydrogen evolution reaction (HER). In this contribution, we report that the amorphous MoSx catalysts prepared by the low temperature thermolysis of the (NH4)(2)MoS4 precursors on carbon clothes (catalyst loading: 3.2 mg/cm(2)) exhibit a Tefal slope of 50.5 mV/dec and a high exchange current density of 1.5 x 10(-3) mA/cm(2) in 0.5 M H2SO4 solutions. Spectroscopic studies of the amorphous MoSx catalysts show that the increase of HER efficiency is positively correlated to the concentration of S-2(2-) species, providing strong evidence to support the argument that S-2(2-) is an active species for electrocatalytic HER. Additionally, the method for preparing catalysts is simple, scalable and applicable for large-scale production. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Highly Efficient Electrocatalytic Hydrogen Production by MoSx Grown on Graphene-Protected 3D Ni Foams
(2013-02-06)
Chang, Yung-Huang
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Lin, Cheng-Te
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Chen, Tzu-Yin
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Hsu, Chang-Lung
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Lee, Yi-Hsien
Label-free detection of DNA hybridization using transistors based on CVD grown graphene
(2013-03-15)
Chen, Tzu-Yin
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Phan Thi Kim Loan
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Hsu, Chang-Lung
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Lee, Yi-Hsien
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Wang, Jacob Tse-Wei
The high transconductance and low noise of graphene-based field-effect transistors based on large-area monolayer graphene produced by chemical vapor deposition are used for label-free electrical detection of DNA hybridization. The gate materials, buffer concentration and surface condition of graphene have been optimized to achieve the DNA detection sensitivity as low as 1 pM (10(-12) M), which is more sensitive than the existing report based on few-layer graphene. The graphene films obtained using conventional PMMA-assisted transfer technique exhibits PMMA residues, which degrade the sensing performance of graphene. We have demonstrated that the sensing performance of the graphene samples prepared by gold-transfer is largely enhanced (by 125%). (C) 2012 Elsevier B.V. All rights reserved.
Label-Free Electrical Detection of DNA Hybridization on Graphene using Hall Effect Measurements: Revisiting the Sensing Mechanism
(2013-05-13)
Lin, Cheng-Te
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Phan Thi Kim Loan
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Chen, Tzu-Yin
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Liu, Keng-Ku
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Chen, Chang-Hsiao
There is broad interest in using graphene or graphene oxide sheets as a transducer for label-free and selective electrical detection of biomolecules such as DNA. However, it is still not well explored how the DNA molecules interact with and influence the properties of graphene during the detection. Here, Hall effect measurements based on the Van der Pauw method are used to perform single-base sequence selective detection of DNA on graphene sheets, which are prepared by chemical vapor deposition. The sheet resistance increases and the mobility decreases with the addition of either complementary or one-base mismatched DNA to the graphene device. The hole carrier concentration of the graphene devices increases significantly with the addition of complementary DNA but it is less affected by the one-base mismatched DNA. It is concluded that the increase in hole carrier density, indicating p-doping to graphene, is better correlated with the DNA hybridization compared to the commonly used parameters such as conductivity change. The different electrical observations of p-doping from Hall effect measurements and n-doping from electrolyte-gated transistors can be explained by the characteristic morphology of partially hybridized DNA on graphene and the mismatch between DNA chain length and Debye length in electrolytes.
Three- Dimensional Molybdenum Sulfi de Sponges for Electrocatalytic Water Splitting
(2014-03-01)
Chang, Yung-Huang
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Wu, Feng-Yu
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Chen, Tzu-Yin
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Hsu, Chang-Lung
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Chen, Chang-Hsiao