Browsing by Author "Liu, Yen-Yu"

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A nanoporous optically transparent CdS-pHEMA hybrid with high optical sensing capability to dielectric liquids
(2009-03-04)
Liao, Hung-Chou
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Liu, Yen-Yu
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Chen, San-Yuan
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Liu, Dean-Mo
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材料科學與工程學系
A hydrogel-based functional hybrid with highly uniformly dispersed nanoparticulate CdS semiconductors is proposed. The hybrid is synthesized using an in situ polymerization following an in situ chemical reduction, where the resulting particle size and the distribution of CdS nanocrystals (NCs) can be narrowly manipulated. The hybrids, containing a relatively small amount of the CdS NCs, exhibit a pronounced photoluminescence spectrum shift when in contact with a number of dielectric liquids and such a pronounced dielectric-confinement effect has been experimentally verified and modeled in this study. The sensing capability of the hybrids with respect to dielectric liquids or molecules can be optically characterized and varied depending upon the intensity of the dielectric environment surrounding the hybrids. This work suggests that the transparent, nanoporous CdS-pHEMA hybrids can be used as highly efficient optical sensing materials.
A novel nanomolar highly selective fluorescent probe for imaging mercury (II) in living cells and zebrafish
(2018-12-20)
Liu, Yen-Yu
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Naha, Sanay
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Thirumalaivasan, Natesan
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Velmathi, Sivan
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Wu, Shu-Pao
A novel fluorescent probe, PES, which contains a bisethylsulfane moiety, displayed high specificity for Hg2+ detection. With Hg2+, PES showed significant blue fluorescence enhancement, while the metal ions Al3+, Ag+, Cr3+, Ca2+, Cu2+, Co2+, Cd2+, Fe3+, Fe2+, Mn2+, Mg2+, Ni2+, Zn2+, and Pb2+ exhibited only negligible fluorescence change. PES has been found to be an effective quantitative detector (LOD, 57 nM) for Hg2+ in semi-aqueous medium based on the Hg2+-induced removal of bisethylsulfane. It resulted in a turn-on blue fluorescence response. The fluorescence enhancement induced by Hg2+ was observed over the pH range of 4-10. Our fluorescence cell-imaging experiments revealed the applicability of the new probe, PES, to be a reliable and effective fluorescent marker for Hg2+ in living cells.
Electrochemical Behavior of Nano Cu/Poly(2-hydroxyethyl methacrylate) Composite
(2009-02-01)
Liu, Yen-Yu
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Liu, Dean-Mo
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Do, Jing-Shan
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Chen, San-Yuan
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材料科學與工程學系
A novel electro-activated Cu/pHEMA nanocomposite was fabricated by coupling nano copper particles with poly(2-hydroxyethyl methacrylate) (pHEMA) matrix. The nano-sized copper particles ranging from 5 nm to 10 nm were in-situ synthesized in the presence of three-dimensional polymer matrixes by photo-polymerization of the copper ions with the HEMA monomer and followed by a strong reducing reaction. The electrochemical behaviors of the Cu/pHEMA nanocomposite were charcterized by cyclic voltammetry and alternating current impedance method. The results showed that the redox behavior of Cu/pHEMA nanocomposite was controlled by the crystallinity of copper particles and the interaction between copper and pHEMA.
In situ synthesis of hybrid nanocomposite with highly order arranged amorphous metallic copper nanoparticle in poly(2-hydroxyethyl methacrylate) and its potential for blood-contact uses
(2008-11-01)
Liu, Yen-Yu
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Liu, Dean-Mo
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Chen, San-Yuan
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Tung, Tsan-Hua
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Liu, Tse-Ying
A hybrid consisting of a highly ordered nanostructure of metallic Cu(0) nanoparticles embedded in a poly(2-hydroxyethyl methacrylate) (pHEMA) matrix was successfully synthesized by in situ photopolymerization, followed by in situ chemical reduction. The evolution of an ordered nanostructure of Cu(0) showing a nearly amorphous nature is discussed, and it is proposed that it is due to a coupling interaction between the Cu precursor and the unpaired O of the COOR group, associated with water molecules, among pHEMA molecules. The hybrids showed a negative surface charge and considerable improvement in blood compatibility compared to neat pHEMA and the widely used biomaterial polysulfonate. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Structural Evolution and Copper-Ion Release Behavior of Cu-pHEMA Hybrids Synthesized In Situ
(2009-11-01)
Liu, Yen-Yu
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Tung, Tsan-Hua
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Liu, Kun-Ho
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Chen, San-Yuan
;
Liu, Dean-Mo
A novel Cu-pHEMA hybrid was successfully prepared by in situ photopolymerization of 2-hydroxyethyl methacrylate (HEMA) monomer in the presence of COP copper ions, following an in situ chemical reduction. Experimental observations indicate that intermolecular interactions such as the coupling force and hydrogen bonding between the Cu and the hydroxyl groups further stabilize the hybrid structure to a considerable extent. Localization of the metallic copper particles within the pHEMA network structure as a result of those intermolecular interactions gives rise to the formation of discretely distributed nanocrystallites with particle sizes ranging from 5 to 25 nm in diameter, A crystallographic change of the Cu nanophase from an amorphous-like to a crystalline structure is observed as the H(2)O:HEMA molar ratio increases, upon synthesis, accompanied with an increase in the particle size, A relatively slow and sustained release of the Cu (in the form of cupric ions) from the hybrids was measured for a time period of about 10 days, which also illustrates a Cu(II)-induced proliferation of the endothelial cells over a relatively small range of release rate of the Cu from the hybrids. Such a new type of Cu-loaded hybrid hydrogel is expected to be compatible and may be considered as a candidate biomaterial for biomedical/therapeutic uses.
Synthesis and characterization of nanoporous SiO2/pHEMA biocomposites
(2008-08-01)
Liu, Yen-Yu
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Liu, Tse-Ying
;
Chen, San-Yuan
;
Liu, Dean-Mo
;
材料科學與工程學系
Porous SiO2/pHEMA biocomposites were synthesized in situ by incorporating silica nanoparticles with a hydroxyethyl methacrylate (HEMA) monomer, following a UV-induced photopolymerization. The nanostructure of the composites was characterized and the resulting physical properties were examined. The release kinetics of the model molecule-vitamin B12-and the hemocompatibility of the porous SiO2/pHEMA composites were investigated. Heterogeneous reaction kinetics is proposed to be the formation mechanism of the nanoporosity in the pHEMA matrix as a result of incorporating silica nanoparticles following photopolymerization. Experimental results also demonstrated that the incorporation of the silica nanoparticles into the pHEMA matrix not only enhanced the mechanical property but also maintained a good hemocompatibility of the resulting biocomposites. In addition, it was observed that the drug release profile of the composites (in the form of a membrane) can be precisely regulated from a two-stage pattern to one-stage pattern by varying the concentration of both the SiO2 nanoparticles and HEMA monomer during synthesis. The permeability of the model drug was enhanced by two orders of magnitude from 4.22 x10(-7) cm(2)/h to 3.92 x 10(-5) cm(2)/h by controlling the micro-to-nanostructure of the composites. The platelet adhesion experiment demonstrated low aggregation of the platelets on the surface of the biocomposite membranes, indicating a promising antithrombotic property.