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151.
T. Trimaille C. Chaix T. Delair C. Pichot H. Teixeira C. Dubernet P. Couvreur 《Colloid and polymer science》2001,279(8):784-792
Cationic nanoemulsions containing an oily core as potential carriers of nucleic acids were prepared by a solvent displacement
method in the presence of a nonionic surfactant (Pluronic F68). With a view to functionalize such nanoemulsions for further
incorporation of a fusogenic peptide, a poly(maleic anhydride-alt-methyl vinyl ether) (M
n=67,000) grafted with variable amount of acetylspermine (or acetylspermidine) and decylamine was nanodeposited during the
nanoemulsion formation step. Functionalized nanoemulsions were characterized in terms of particle size (by quasi-elastic light
scattering and electron microscopy), electrophoretic mobility and long-term stability as a function of the amount of polymer
used in the formulation. It was found that increases in the level of the copolymer led to a reduction in the particle size
and a decrease in colloidal stability. In addition, the incorporation of the grafted copolymers at the interface of the nanoemulsions
was clearly evidenced, a shift towards low pH at the point of zero charge being attributed to the formation of carboxylic
groups induced by hydrolysis of the residual maleic anhydride groups of the copolymer.
Received: 1 September 2000 / in revised form: 29 November 2000 Accepted: 12 December 2000 相似文献
152.
离子液体对某些无机和有机物溶解性能好、液态温度和电化学窗口范围宽、热稳定性高、易制备,因而近年来成为国内外研究的热点,目前的离子液体大多由烷基吡啶或双烷基咪唑季铵盐阳离子与氯铝酸根、氟硼酸根、六氟磷酸根以及其它大的阴离子构成,在季铵盐类离子液体中, 相似文献
153.
N‐Arylaminomethyl‐3H‐1,3,4‐oxadiazole‐2‐thiones 2a,b were prepared from the corresponding N‐arylglycinoylhydrazides. A number of their thioglycoside derivatives 4–7a–c and S‐functionalized analogs 8–11a,b were synthesized by the reaction with different acetobromosugars and acyclic hydroxyalkylating agents. The antiviral activity of a number of the synthesized compounds against herpes simplex virus type 1 (HSV‐1) and hepatitis A virus (HAV) was evaluated. Compounds 5a and 5b showed promising results against HAV. 相似文献
154.
The heterogeneous carbonyl allylation of aldehydes and ketones with allylic chlorides was achieved in DMF using SnCl2 as reducing agent at 25-40 °C in the presence of a 3-(2-aminoethylamino)propyl-functionalized MCM-41-immobilized palladium(II) complex [MCM-41-2N-Pd(II)], yielding a variety of homoallylic alcohols in good to high yields. This heterogeneous palladium catalyst exhibited higher activity than (N-propylethylenediamine)PdCl2 and can be recovered and recycled by a simple filtration of the reaction solution and used for at least 5 consecutive trials without any decreases in activity. 相似文献
155.
In this work, an advanced sandwich-type electrochemical aptasensor for thrombin was proposed by integrating hemin/G-quadruplex with functionalized graphene-Pd nanoparticles composites (PdNPs-RGs). The hemin/G-quadruplex formed by intercalating hemin into thrombin binding aptamer (TBA), firstly acted as a NADH oxidase, assisting the oxidation of NADH to NAD+ accompanying with the generation of H2O2 in the presence of dissolved O2. Subsequently, the hemin/G-quadruplex acted as HRP-mimicking DNAzyme that rapidly bioelectrocatalyze the reduction of the produced H2O2. At the same time, the Pd nanoparticles supported on p-iodoaniline functionalized graphene were also adopted to catalyze the reduction of H2O2. Thus, with the dual catalysis, a dramatically amplified electrochemical signal could be obtained. Besides, the avidin–biotin system for binding aptamer sequences on electrodes not only improved the sensitivity of thrombin analysis but also obtained an acceptable repeatability of the aptasensor. With several factors mentioned above, a wide linear ranged from 0.1 pM to 50 nM was acquired with a relatively low detection limit of 0.03 pM (defined as S/N = 3). These excellent performances provided our approach a promising way for ultrasensitive assay in electrochemical aptasensors. 相似文献
156.
Zimple Matharu Pratibha Pandey M. K. Pandey Vinay Gupta B. D. Malhotra 《Electroanalysis》2009,21(14):1587-1596
Mediator free enzyme sensor has been fabricated by covalently immobilizing cholesterol oxidase (ChOx) onto 11‐mercaptoundecanoic acid functionalized gold nanoparticles (MUDA‐AuNPs) – octadecylamine (ODA) hybrid Langmuir–Blodgett film. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) studies reveal that MUDA‐AuNP/ODA LB film has good affinity for ChOx and provides favorable microenvironment for direct electron transfer between enzyme and electrode. Interference free estimation of cholesterol has been realized at 0.3 V with linear range from 25 to 500 mg/dL, detection limit of 23.38 mg/dL, sensitivity of 1.085 μA mM?1 and response time of 20 s at pH 7.0. 相似文献
157.
Dipak Kumar Dutta J. Derek Woollins Alexandra M.Z. Slawin Amy L. Fuller Biswajit Deb Podma Pollov Sarmah Madan Gopal Pathak Dilip Konwar 《Journal of molecular catalysis. A, Chemical》2009,313(1-2):100-106
The reaction of dimeric rhodium precursor [Rh(CO)2Cl]2 with two molar equivalent of 1,1,1-tris(diphenylphosphinomethyl)ethane trichalcogenide ligands, [CH3C(CH2P(X)Ph2)3](L), where X = O(a), S(b) and Se(c) affords the complexes of the type [Rh(CO)2Cl(L)] (1a–1c). The complexes 1a–1c have been characterized by elemental analyses, mass spectrometry, IR and NMR (1H, 31P and 13C) spectroscopy and the ligands a–c are structurally determined by single crystal X-ray diffraction. 1a–1c undergo oxidative addition (OA) reactions with different electrophiles such as CH3I, C2H5I and C6H5CH2Cl to give Rh(III) complexes of the types [Rh(CO)(COR)ClXL] {R = –CH3 (2a–2c), –C2H5 (3a–3c); X = I and R = –CH2C6H5 (4a–4c); X = Cl}. Kinetic data for the reaction of a–c with CH3I indicate a first-order reaction. The catalytic activity of 1a–1c for the carbonylation of methanol to acetic acid and its ester is evaluated and a higher turn over number (TON = 1564–1723) is obtained compared to that of the well-known commercial species [Rh(CO)2I2]− (TON = 1000) under the reaction conditions: temperature 130 ± 2 °C, pressure 30 ± 2 bar and time 1 h. 相似文献
158.
Hong‐gang Liao Hong Wu Jun Wang Jun Liu Yan‐Xia Jiang Shi‐Gang Sun Yuehe Lin 《Electroanalysis》2010,22(19):2297-2302
This paper describes the direct electrochemistry and electrocatalysis of myoglobin immobilized on graphene‐cetylramethylammonium bromide (CTAB)‐ionic liquid nanocomposite film on a glassy carbon electrode. The nanocomposite was characterized by transmission electron microscopy, scanning electron microscopy, X‐ray photoelectron spectroscopy, and electrochemistry. It was found that the high surface area of graphene was helpful for immobilizing more proteins and the nanocomposite film could provide a favorable microenvironment for MB to retain its native structure and activity and to achieve reversible direct electron transfer reaction at an electrode. The ionic liquid may play dual roles here: it keeps the protein's activity and improves stability of the nanocomposite film; it also serves as a binder between protein and electrode, therefore, enhancing the electron transfer between the protein and the electrode. The nanocomposite films also exhibit good stability and catalytic activities for the electrocatalytic reduction of H2O2. 相似文献
159.
Taste sensing with polyacrylic acid grafted cellulose membrane 总被引:1,自引:0,他引:1
There are reports of fabrication of taste sensor by adsorbing lipids into Millipore filter paper, which improved the taste sensing efficiency of membrane remarkably. We have made an attempt to prepare taste sensor material by grafting polyacrylic acid (PAA) to cellulose. The research work covers polymer membrane preparation, morphology study, and structural characterization of the membrane and study of the taste sensing characteristics of this membrane for five different taste substances. FTIR spectroscopic analysis and SEM were done to get an idea about the structure and morphology of the PAA grafted cellulose membrane. Surface charge density of the membrane was estimated. The sensor characteristics like temporal stability, response stability, response to different taste substances, and reproducibility of sensing performance were studied using PAA grafted cellulose membrane. Sensor device prepared with this membrane has shown distinct response patterns for different taste substances in terms of membrane potential. Threshold concentrations of PAA grafted cellulose membrane for HCl, NaCl, quinine-hydrochloride (Q-HCl), sucrose and monosodium glutamate are 0.001 mM, 0.01 mM, 0.08 mM, 0.08 mM and 0.01 mM, respectively. The threshold concentrations except that in Q-HCl are below human threshold concentrations. Membranes also showed characteristic response patterns for organic acids like acetic acid, citric acid, formic acid, etc., mineral acids like HCl, H2SO4 and HNO3, etc., salts, bitter substances, sweet substances and umami substances. Sensor device prepared with this membrane has excellent shelf life. 相似文献
160.
The reaction of anhydrous FeBr2 with two equivalents of in situ generated anionic aryloxo-functionalized N-heterocyclic carbene [NaO-4,6-di-C(CH3)3-C6H2-2-CH2{C(NCHCHNR)}] (R = CH(CH3)2, NaL1; R = CH2Ph, NaL2) affords two bis-ligand Fe(II) complexes (1) and (2) in good yield, respectively. Attempt to synthesize mono-ligand Fe(II) bromide by the 1:1 molar ratio of NaL to FeBr2 is unsuccessful, the same complexes of 1 and 2 were obtained. Both of 1 and 2 have been fully characterized by elemental analysis, 1H NMR spectra and X-ray structure determination. Preliminary studies show that 1 can catalyze the ring-opening polymerization of ε-caprolactone as a single component catalyst. The mechanism of the present ROP of ε-caprolactone has been investigated by the end group analysis. 相似文献