Browsing by Author "Hsieh, You-Zung"

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1-Butyl-3-methylimidazolium-based ionic liquids and an anionic surfactant: Excellent background electrolyte modifiers for the analysis of benzodiazepines through capillary electrophoresis
(2010-04-23)
Su, Hsiu-Li
;
Kao, Wan-Chun
;
Lin, Kuan-Wen
;
Lee, Cheng-yu
;
Hsieh, You-Zung
In this study, we found that adding 1-butyl-3-methylimidazolium-based ionic liquids (ILs) and sodium dodecyl sulfate (SOS) as modifiers in the background electrolyte (BGE) for capillary electrophoresis enhanced the separation of benzodiazepines. In particular, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([BMIM][NTf(2)]) was the best IL additive for the separation system because its anionic moiety interacted favorably with the benzodiazepines. We added SDS because of its known effect on the separation of hydrophobic analytes. We optimized the separation conditions in terms of the concentrations of the IL, SOS, and organic solvent, the pH, and the BGE's ionic strength. The optimal BGE, containing 170 mM [BMIM][NTf(2)] and 10 mM SOS, provided baseline separation, high efficiency, and satisfactory peak shapes for the benzodiazepines. The separation mechanism was based on heteroassociation between the anionic moiety of the IL and the benzodiazepines, with SOS improving the resolution of the separation. The limits of detection for the seven analytes ranged from 2.74 to 4.42 mu g/mL. We subjected a urine sample to off-line solid phase extraction (SPE) prior to the analysis of its benzodiazepine content. Our experimental results reveal that the combination of [BMIM][NTf(2)] and SDS provides adequate separation efficiency for its application to CE analyses of benzodiazepines after SPE concentration. (C) 2010 Elsevier B.V. All rights reserved.
A Pentacyclic Nitrogen-Bridged Thienyl-Phenylene-Thienyl Arene for Donor-Acceptor Copolymers: Synthesis, Characterization, and Applications in Field-Effect Transistors and Polymer Solar Cells
(2012-09-01)
Tseng, Cheng-An
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Wu, Jhong-Sian
;
Lin, Tai-Yen
;
Kao, Wei-Shun
;
Wu, Cheng-En
A pentacyclic benzodipyrrolothiophene (BDPT) unit, in which two outer thiophene rings are covalently fastened with the central phenylene ring by nitrogen bridges, was synthesized. The two pyrrole units embedded in BDPT were constructed by using one-pot palladium-catalyzed amination. The coplanar stannylated Sn-BDPT building block was copolymerized with electron-deficient thieno[3,4-c]pyrrole-4,6-dione (TPD), benzothiadiazole (BT), and dithienyl-diketopyrrolopyrrole (DPP) acceptors by Stille polymerization. The bridging nitrogen atoms make the BDPT motif highly electron-abundant and structurally coplanar, which allows for tailoring the optical and electronic properties of the resultant polymers. Strong photoinduced charge-transfer with significant band-broadening in the solid state and relatively higher oxidation potential are characteristic of the BDPT-based polymers. Poly(benzodipyrrolothiophene-alt-benzothiadiazole) (PBDPTBT) achieved the highest field-effect hole mobility of up to 0.02 cm2?V-1?s-1. The photovoltaic device using the PBDPTBT/PC71BM blend (1:3, w/w) exhibited a Voc of 0.6 V, a Jsc of 10.34 mA?cm-2, and a FF of 50?%, leading to a decent PCE of 3.08?%. Encouragingly, the device incorporating poly(benzodipyrrolothiophene-alt-thienopyrrolodione) (PBDPTTPD)/PC71BM (1:3, w/w) composite delivered a highest PCE of 3.72?%. The enhanced performance arises from the lower-lying HOMO value of PBDPTTPD to yield a higher Voc of 0.72 V.
A pyrophosphatase biosensor with photocurrent analysis
(2019-04-01)
Lee, Cheng-Yu
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Liao, Chi-Hsiang
;
Tso, Jen-Te
;
Hsieh, You-Zung
;
交大名義發表
A light-induced photochemical biosensor was developed for the analysis of inorganic pyrophosphatase (PPase). PPase hydrolyzes pyrophosphate (PPi) into two independent o-phosphate ions. Two PPi units can chelate a copper ion (Cu2+), forming a PPi-Cu2+-PPi complex and preventing the Cu2+ triggers other reactions. A transparent indium tin oxide (ITO) electrode was coated with a layer of CdS quantum dots (QDs), and then 3,4-diaminobenzoic acid (DBA) was deposited as the anchor. A solution of the PPi-Cu2+-PPi complex and o-phenylenediamine (OPD) was mixed with the analytical sample and then a drop of the mixture was placed on the modified ITO electrode. In the absence of PPase, no reaction occurred between OPD and DBA. A photocurrent was obtained upon excitation of the CdS QDs under light. In the presence of PPase, Cu2+ was released from the complex, triggering the reaction of OPD with DBA on the electrode surface, thereby shielding the CdS QDs from excitation by the light. The observed photocurrent decreased. The difference in the two measured photocurrents corresponded to the activity of PPase. This photochemical biosensor had excellent sensitivity for PPase in the range from 0.8 to 5000 mU, with a limit of detection of 0.41 mU.
Analysis of Calix[4]arenes Using Nonaqueous Capillary Electrophoresis
(2013-01-01)
Su, Hsiu-Li
;
Lee, Yi-Ping
;
Hung, Huan-Yi
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Lee, Cheng-Yu
;
Chung, Wen-Sheng
In nonaqueous capillary electrophoresis (NACE), an organic solvent is used in place of an aqueous medium as the background solution to improve the solubility and selectivity for hydrophobic analytes. In this study, we employed NACE with UV detection for the analysis of eight calix[4]arenes. We examined the influence of several parameters-the buffer composition, the nonaqueous solvent's composition and proportion, and the concentration of the electrolyte of the nonaqueous buffer-on the efficiency of the electrophoretic separation. The separation was achieved through the analyte's different effective mobility via different degrees of deprotonation on the phenolic OH groups of the calix[4]arene. This deprotonation can further affect the analyte's ability to form a complex with the metal ion. The optimized background electrolyte (BGE), comprising a mixture of N-methylformamide/acetonitrile (30:70, v/v) and 100 mM AcOH/20 mM NH4OAc, provided rapid (<11 min) separation of the calix[4]arenes with good resolution. The relative standard deviations of the migration times for the eight analytes were all less than 1%. Within the calibration concentration range, the coefficients of determination (R-2) were all greater than 0.9914. Thus, the present study demonstrated NACE can provide adequate separation for the analysis of calix[4]arenes.
Analysis of metal ion impurities in liquid crystals using high resolution inductively coupled plasma mass spectrometry
(2012-11-01)
Hung, Huan-Yi
;
Lu, Chien-Wei
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Lee, Cheng-Yu
;
Hsu, Chain-Shu
;
Hsieh, You-Zung
We have developed a method, using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS), to directly analyze metal ion impurities in liquid crystals (LCs). From measurements of resistivity, a commonly used technique for quality control of liquid crystal display (LCD) cells, we found that the resistivities of the LCs decreased significantly upon progressing through the different stages of the LCD cell manufacturing process. We determined the levels of metal ion impurities in the LCs through direct loading of diluted LC samples into the HR-ICP-MS system at a steady flow rate. Solutions featuring LC contents of 10% (v/v) were formed by dissolving each LC in isopropanol (IPA) containing acetone as a modifier. We quantified the trace metal ion impurities in the LC samples using a certified standard of metal ions diluted in IPA (external calibration) without the need for digestion pretreatment. Next, we compared the levels of metal ion impurities with the resistivities of the LCs at the different stages of the LCD cell manufacturing process. We confirmed that the resistivities of the LCs decreased as the total levels of metal ion impurities in the LCs increased. The total content of metal ion impurities added into the LC was higher in the siphoning process than in the one-drop filling process during the fabrication of LCD cells. The HR-ICP-MS method could, therefore, be used to directly measure metal ion impurities in LCs during the LCD cell manufacturing process, potentially replacing resistivity measurements of LCs as a means of quality control. We suggest setting 1400 ng L-1 as the limit of the total metal ion concentration in LCs used for LCD cell manufacturing. We used the HR-ICP-MS method to analyze a stained LCD panel to confirm that the content of metal ion impurities was indeed significantly greater in the stained area of the defected LCD. HR-ICP-MS appears to be a promising technique for the direct and effective analyses of metal ion impurities in LCs.
Chaotropic salts: Novel modifiers for the capillary electrophoretic analysis of benzodiazepines
(2008-08-01)
Su, Hsiu-Li
;
Lan, Min-Tsu
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Hsieh, You-Zung
;
應用化學系
;
Department of Applied Chemistry
This paper describes a CE method for analyzing benzodiazepines using the chaotropic salts lithium trifluoromethanesulfonate (LiOTf), lithium hexafluorophosphate (LiPF6), and lithium bis(trifluoromethanesulfonyl)imide (LiNTf2) as modifiers in the running buffer. Although adequate resolution of seven benzodiazepine analytes occurred under the influence of each of the chaotropic anions, the separation efficiency was highest when bis(trifluoromethanesulfonyl)imide (Tf2N-) was the modifier. We applied affinity CE in conjunction with linear analysis to determine the association constants for the formation of complexes between the Tf2N- anion and the benzodiazepines. According to the estimated Gibbs free energies, the interactions between this chaotropic anion and the benzodiazepines were either ion-dipole or ion-induced dipole interactions. Adding chaotropic salts as modifiers into CE buffers is a simple and reproducible technique for separating benzodiazepines.
Combining aptamer-modified gold nanoparticles with barcode DNA sequence amplification for indirect analysis of ethanolamine
(2018-01-01)
Lee, Cheng-Yu
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Shiau, Ru-June
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Chou, Han-Wen
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Hsieh, You-Zung
;
應用化學系
An indirect analysis strategy for small organic molecules is presented herein, combining aptamermodified gold nanoparticles (AuNPs) with a designed barcode sequence for amplification. Ethanolamine, which could not be analyzed directly through liquid chromatography coupled with mass spectrometry (LC/MS), was used as a model compound to demonstrate the feasibility of the proposed scheme. A poly adenosine barcode sequence was part of the designed cDNA Al (cDNA + barcode sequence) to provide a large number of adenine bases for signal amplification. In the presence of fixed amounts of the aptamer and cDNA Al, the concentration of ethanolamine could be estimated indirectly through measurement of the concentration of the hydrolyzed bases of the unbound cDNA Al. The thiol-terminated aptamer was immobilized on the AuNPs through Au-S self-assembly. The aptamer-immobilized AuNPs were removed, with their bound ethanolamine and cDNA Al, through centrifugation. The unbound cDNA Al remaining in the supernatant was hydrolyzed and analyzed. Through indirect analysis and amplification of the cDNA Al, the concentration of ethanolamine could be analyzed with a linear range (on a logarithmic scale) between 5 and 5000 nM (detection limit: 1.2 nM). This developed method might be applied as a general platform for indirect detection using LC/MS analysis. (C) 2017 Elsevier B.V. All rights reserved.
Combining DNA-stabilized silver nanocluster synthesis with exonuclease III amplification allows label-free detection of coralyne
(2018-12-26)
Lee, Cheng-Yu
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Lin, Shun-Wen
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Wu, Yi-Hsuan
;
Hsieh, You-Zung
;
交大名義發表
In this paper we describe a label-free biosensor for coralyne, prepared by combining DNA-stabilized silver nanoclusters (Ag NCs) with an exonuclease III amplification strategy. An artificial DNA probe having a polyadenine (poly-A) sequence at both the 3'- and 5'-ends was used as a probe to detect coralyne. In the absence of coralyne, the probe existed in a hairpin conformation that left both its 3'- and 5'-ends free. In the presence of coralyne, two adjacent adenine (A) bases in the poly-A sequence of the probe formed an A(2) unit and then coordinated with coralyne through non-Watsone-Crick base pairing. The DNA probe, having captured coralyne, was subsequently digested by exonuclease III, even though the distance between the A(2) units in the A(2)-ecoralynee-A(2) complex would be much larger than that found in common Watsone-Crick base pairing. After digestion, the DNA probe became a single-stranded DNA (ssDNA) residue and released its captured coralyne. The liberated coralyne was then coordinated by another DNA probe having the hairpin conformation; as a result, many ssDNA residues formed after digestion. Two kinds of Ag NCs having different optical utilities were obtained: one corresponding to the hairpin conformational DNA probe and the other to the ssDNA residue. The difference in fluorescence intensity at 588 nm of these two kinds of Ag NCs reflected the concentration of coralyne. The linear range (on a logarithmic scale) for detecting coralyne spanned from 5 to 1000 nM, with an estimated detection limit of 1.83 nM. (C) 2018 Elsevier B.V. All rights reserved.
Determination of cocaine and its metabolites using cation-selective exhaustive injection and sweeping-MEKC
(2008-11-01)
Su, Hsiu-Li
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Feng, Lan-Ing
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Jen, Hsiu-Ping
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Hsieh, You-Zung
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應用化學系
We have employed a high-sensitivity on-line preconcentration method, cation-selective exhaustive injection (CSEI) and sweeping MEKC, for the analysis of cocaine, benzoylecgonine, norcocaine, and cocaethylene. We monitored the effects of several of the CSEI-sweeping-MEKC parameters - including the pH, the concentrations of SDS and organic modifier, the injection length of the high-conductivity buffer, and the injection time of the sample - to optimize the separation process. The optimal BGE was 100 mM phosphoric acid (pH 1.8) containing 75 mM SDS with 10% 2-propanol and 10% tetrahydrofuran as the organic modifier. In addition, electrokinetic injection of the sample at 15 kV for 900 s provided both high separation efficiency and enhanced sweeping sensitivity. The sensitivity enhancements for cocaine, norcocaine, and cocaethylene ranged from 2.06 x 10(4) to 3.96 x 10(4); for benzoylecgonine it was 1.75 x 10(3); the coefficients of determination exceeded 0.9958. The LODs, based on an SIN ratio of 3:1, of sweeping-MEKC ranged from 33.5 to 52.8 ng/mL; in contrast, when using CSEI-sweeping-MEKC the sensitivity increased to range from 29.7 to 236 pg/mL. Under the optimal conditions, we analyzed cocaine in a human urine sample prepared using off-line SPE to minimize the influence of the matrix. The recovery of the SPE efficiency was satisfactory (ca. 74.9-87.6%). Our experimental results suggest that, under the optimal conditions, the CSEI-sweeping-MEKC method can be used to determine cocaine and its metabolites with high sensitivity in human urine.
Disposable aptasensor combining functional magnetic nanoparticles with rolling circle amplification for the detection of prostate-specific antigen
(2018-02-01)
Lee, Cheng-Yu
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Fan, Hsiao-Ting
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Hsieh, You-Zung
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應用化學系
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Department of Applied Chemistry
This paper describes a disposable and accurate aptasensor that functions with signal amplification for prostate-specific antigen (PSA) analysis in neutral (pH 7.4) condition. Combining aptamer-immobilized magnetic nanoparticles with rolling circle amplification (RCA) has provided a PSA detector with adequate sensitivity. In the absence of PSA, a portion of the complementary DNA-primer (cDNA-primer) bound with the aptamer and became the primer for the RCA reaction. The product of RCA contained G-rich bases that bound specifically with methylene blue (MB), thereby providing a measurable signal. In the presence of PSA, the aptamer would bind to it and fold, leading to fewer bound cDNA-primer units. Because the number of RCA primer elements decreased, the signal of MB weakened. The difference in the currents of MB measured in the presence and absence of PSA reflected the concentration of PSA. The intensity of the signal had a linear relationship with the logarithm of the PSA concentration over the range from 100 fM to 10 nM. The correlation of determination (R-2) of this calibration curve was 0.993, with a limit of detection of 22.3 fM. (C) 2017 Elsevier B.V. All rights reserved.
Electrooxidation of catecholamines at carbon nanotube-modified indium tin oxide electrodes
(2008-06-30)
Lin, Kuan-Wen
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Lin, Chang-Hao
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Hsieh, You-Zung
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應用化學系
;
Department of Applied Chemistry
In this study, we prepared carbon nanotube (CNT)/Nafion-modified ITO electrodes and investigated their electrochemical behavior. The CNTs were dissolved in a solution of the ionic polymer Nafion and then CNT/Nafion composite films were deposited onto ITO electrodes through spin-coating of this homogeneous solution. We studied the effects of chemical pretreatment of the CNTs and the pH of the buffer on the electroanalytical behavior of the CNT/Nafion-modified ITO electrodes toward catecholamines. The modified electrodes enhanced the peak current and lowered the overpotentials. We observed high electrooxidative performance for the modified ITO electrodes: the oxidative currents of the catecholamines were up to 125-fold higher than those obtained using bare ITO electrodes. (C) 2008 Elsevier B.V. All rights reserved.
Fabrication of a flexible and disposable microreactor using a dry film photoresist
(2006-06-01)
Tsai, Yuan-Chien
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Yang, Shung-Jim
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Lee, Hsun-Tsing
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Jen, Hsiu-Ping
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Hsieh, You-Zung
In this paper, we demonstrate that a low-cost flexible microreactor can be manufactured using a dry film photoresist in conjunction with photolithographic and hot roll lamination techniques. A microfluidic flow path and sample reservoir patterns were prefabricated in a dry film photoresist tape using traditional photolithographic methods. This tape was sandwiched between two plastic films - wells were prepouched on the cover film - that were bonded upon passage through a hot roll laminator. A simple Plexiglas reactor holder was designed and constructed to use in evaluating the flexible microchip reactor. We demonstrate a chemical synthesis of polyaniline that was performed with this polymeric microreactor using a hydrodynamic flow control system. The fabrication of this microreactor suggests that there is great potential for designing and prototyping disposable microscale reaction systems using dry film photoresist for a range of chemical and biochemical syntheses.
Functional magnetic nanoparticles-assisted electrochemical biosensor for eosinophil cationic protein in cell culture
(2018-03-01)
Lee, Cheng-Yu
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Wu, Li-Ping
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Chou, Tzu-Ting
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Hsieh, You-Zung
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應用化學系
A low-cost electrochemical biosensor, assisted by a new type of functional magnetic nanoparticles (NPs), has been developed to detect eosinophil cationic protein (ECP), a known biomarker of asthma, in cell culture. The heparin-modified magnetic NPs were mixed with a sample solution containing ECP. After ECP had been captured by the NPs, a magnetic field was applied behind a graphite-based screen-printed electrode. The functional magnetic NPs were attracted to the electrode, raising the ECP concentration near its surface. Because of the use of the functional magnetic NPs, the difference in the signal was amplified when applying larger sample volumes for detection, thereby enhancing the sensitivity of the biosensor. This approach provided a linear range for the analysis of the logarithm of the ECP concentration from 1 to 1000 nM, with a coefficient of determination 0.992; the limit of detection was 0.30 nM. The fabricated biosensor displayed good recovery in a cell culture medium incubated with the Beas-2 B cell line. The ability to detect the concentration of ECP in a cell culture at any time point should be useful for explaining contradictory findings regarding the relationship between the initial ECP concentration and the cell line. (c) 2017 Elsevier B.V. All rights reserved.
Glucose sensing by electrochemically grown copper nanobelt electrode
(2009-11-15)
Huang, Ting-Kai
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Lin, Kuan-Wen
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Tung, Sze-Ping
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Cheng, Ta-Ming
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Chang, I-Chun
A simple design of growing Cu nanobelt (NB) electrode for glucose sensing is presented. Cu NBs were grown directly on carbon electrodes by using electrochemical deposition. The average width, thickness and length of the NBs were about 50 nm, 20 nm and several tens of micrometers, respectively. Cyclic voltammetric (CV) experiments showed that a Cu NB electrode grown by a reduction charge of 0.5 C on a substrate of 0,018 cm(2) enhanced glucose oxidation ability. For glucose sensing, the electrode exhibited a high sensitivity of 79.8 mu A/mM and a measurable detection limit of 10 mu M in amperometric detection. (C) 2009 Elsevier B.V. All rights reserved.
Graphene Oxide Based Nanocarrier Combined with a pH-Sensitive Tracer: A Vehicle for Concurrent pH Sensing and pH-Responsive Oligonucleotide Delivery
(2015-06-03)
Hsieh, Chia-Jung
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Chen, Yu-Cheng
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Hsieh, Pei-Ying
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Liu, Shi-Rong
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Wu, Shu-Pao
We chemically tuned the oxidation status of graphene oxide (GO) and constructed a GO-based nanoplatform combined with a pH-sensitive fluorescence tracer that is designed for both pH sensing and pH-responsive drug delivery. A series of GOs oxidized to distinct degrees were examined to optimize the adsorption of the model drug, poly dT(30). We determined that highly oxidized GO was a superior drug-carrier candidate in vitro when compared to GOs oxidized to lesser degrees. In the cell experiment, the synthesized pH-sensitive rhodamine dye was first applied to monitor cellular pH; under acidic conditions, protonated rhodamine fluoresces at 588 mm (lambda(ex) = 561 nm). When the nanocarrier was introduced into cells, a rhodamine-triggered competition reaction occurred, and this led to the release of the oligonucleotides and the quenching of rhodamine fluorescence by GO. Our results indicate high drug loading (FAM-dT(30)/GO = 25/50 mu g/mL) and rapid cellular uptake (<0.5 h) of the nanocarrier which can potentially be used for targeted RNAi delivery to the acidic milieu of tumors.
In-channel simplified decoupler with renewable electrochemical detection for microchip capillary electrophoresis
(2008-06-30)
Lin, Kuan-Wen
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Huang, Yan-Kai
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Su, Hsiu-Li
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Hsieh, You-Zung
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應用化學系
Electrochemical (EC) detection is comparable to fluorescence detection in that it is simple to perform, economical, and highly sensitive. In this study, we used replica molding to fabricate a PDMS microchip for microchip capillary electrophoresis (CE). A decoupler electrode and a working electrode were implanted into the PDMS chip during the molding process to prevent leakage into the electrode channel. The working electrode could be renewed readily through its slight withdrawal (ca. 3 mm) from the PDMS; its detection ability was highly reproducible in the microchip CE-EC system. The relative standard deviation (R.S.D.) of the detecting current for the renewed working electrode was 1.2% (n = 5). The calibration curves were linear for both dopamine and catechol analytes over the concentration range 10-1000 mu M, with coefficients ofdetermination (R-2) of 0.999 and 0.976, respectively. The number of theoretical plates (N/m) for these analytes was greater than 133,000. (C) 2008 Elsevier B.V. All rights reserved.
Non-metallic nanomaterials in cancer theranostics: a review of silica- and carbon-based drug delivery systems
(2013-08-01)
Chen, Yu-Cheng
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Huang, Xin-Chun
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Luo, Yun-Ling
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Chang, Yung-Chen
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Hsieh, You-Zung
The rapid development in nanomaterials has brought great opportunities to cancer theranostics, which aims to combine diagnostics and therapy for cancer treatment and thereby improve the healthcare of patients. In this review we focus on the recent progress of several cancer theranostic strategies using mesoporous silica nanoparticles and carbon-based nanomaterials. Silicon and carbon are both group IV elements; they have been the most abundant and significant non-metallic substances in human life. Their intrinsic physical/chemical properties are of critical importance in the fabrication of multifunctional drug delivery systems. Responsive nanocarriers constructed using these nanomaterials have been promising in cancer-specific theranostics during the past decade. In all cases, either a controlled texture or the chemical functionalization is coupled with adaptive properties, such as pH-, light-, redox- and magnetic field-triggered responses. Several studies in cells and mice models have implied their underlying therapeutic efficacy; however, detailed and long-term in vivo clinical evaluations are certainly required to make these bench-made materials compatible in real bedside circumstances.
Oligonucleotides as 'bio-solvent' for in situ extraction and functionalisation of carbon nanoparticles
(2014-01-01)
Chen, Yu-Cheng
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Wen, Cheng-Che
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Liau, Ian
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Hsieh, You-Zung
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Hsu, Hsin-Yun
A simple yet novel one-pot approach is developed to prepare carbon nanoparticles with diameters of similar to 2 nm and modified by oligonucleotides. We use single-stranded deoxyribonucleic acid (ssDNA), which serves as a unique 'bio-solvent' for carbon nanoparticle (CNP) preparation and as a target molecule for functionalisation. Proposed interactions relevant to the stabilisation of the final oligonucleotide-CNP complex include pi-pi stacking and pi-HN bonding with sp(2) carbon atoms on the CNP surface. Furthermore, oligonucleotide-enriched CNPs can be readily extracted within seconds from a crude mixture of single-walled carbon nanotubes (SWCNTs) without any need for post-synthesis chemical modification. The established CNPs are biocompatible, possess intrinsic fluorescence, and do not result in the undesirable photobleaching effect, rendering them potential candidates for in vivo biological applications.
Oligonucleotides as \'bio-solvent\' for in situ extraction and functionalisation of carbon nanoparticles
(2014-01-01)
Chen, Yu-Cheng
;
Wen, Cheng-Che
;
Liau, Ian
;
Hsieh, You-Zung
;
Hsu, Hsin-Yun
A simple yet novel one-pot approach is developed to prepare carbon nanoparticles with diameters of similar to 2 nm and modified by oligonucleotides. We use single-stranded deoxyribonucleic acid (ssDNA), which serves as a unique \'bio-solvent\' for carbon nanoparticle (CNP) preparation and as a target molecule for functionalisation. Proposed interactions relevant to the stabilisation of the final oligonucleotide-CNP complex include pi-pi stacking and pi-HN bonding with sp(2) carbon atoms on the CNP surface. Furthermore, oligonucleotide-enriched CNPs can be readily extracted within seconds from a crude mixture of single-walled carbon nanotubes (SWCNTs) without any need for post-synthesis chemical modification. The established CNPs are biocompatible, possess intrinsic fluorescence, and do not result in the undesirable photobleaching effect, rendering them potential candidates for in vivo biological applications.
One-pot formation of fluorescent gamma-lactams having an alpha-phosphorus ylide moiety through three-component alpha(delta ')-Michael reactions of phosphines with an enyne and N-tosyl aldimines
(2014-01-07)
Lin, Yu-Wei
;
Deng, Jie-Cheng
;
Hsieh, You-Zung
;
Chuang, Shih-Ching
;
應用化學系
We demonstrate a straightforward synthesis of gamma-lactams possessing an a-phosphorus Aide moiety from assembly of phosphines, N-tosyl aldimines and an enyne through an initial alpha(delta')-attack of phosphines to an enyne in up to 79% yield. The investigated multicomponent reaction tolerates a variety of triaryl-phosphines and electron-poor aldimines to give gamma-lactams in one pot. One of the lactams, with the tri(p-tol)phosphine and 4-cyanophenyl moiety, exhibits fluorescence emission at 447 nm with a quantum yield of 0.11.