The electrochemiluminescence of bis(2, 2′-bipyridine) (dipyrido[3, 2-a:2′ 3′-c]phenazine-N4N5) ruthenium(II) ([Ru(bpy)2(dppz)]2+) was used to monitor deoxyribonucleic acid (DNA) charge transfer with tri-n-propylamine as a coreactant. This system was used to measure damage to DNA induced by perfluorooctanoic acid. Fifteen-base pairs of double-stranded DNA with a thiol group at the 5′ end position were covalently bonded to a gold electrode. An electrochemiluminescence sensor was then constructed by incubating the modified gold electrode in [Ru(bpy)2(dppz)]2+ solution for 30 min. For comparison, single-stranded DNA, well-matched double-stranded DNA, and single base-mismatched double-stranded DNA were assembled on the gold surface. The results showed that the electrochemiluminescence behavior of the DNA sensors were unique. The electrochemiluminescence decreased when the [Ru(bpy)2(dppz)]2+-DNA ECL sensor was incubated in a perfluorooctanoic acid solution. The damage to DNA caused by perfluorooctanoic acid was monitored using a combination of DNA charge transfer theory and the interaction between DNA and [Ru(bpy)2(dppz)]2+. The detection limit for perfluorooctanoic acid was 1 × 10?12 mol/L. [Ru(bpy)2(dppz)]2+ was shown to be a sensitive electrochemiluminescence sensor for the determination of DNA damage. 相似文献
An electrochemical competition method was used to study the interaction of carbaryl with natural double-stranded DNA (ds-DNA). Layer-by-layer films of negatively charged natural ds-DNA and polycationic poly (diallyldimethylammonium chloride) were assembled on the surface of a glassy carbon electrode. The DNA intercalator [Ru(bpy)2(dppz)]2+ (bpy?=?2, 2′-bipyridine, dppz?=?dipyrido [3, 2-a: 2′,3′-c] phenazine) was chosen as an electrochemical probe. Tripropylamine was used as an electron donor to chemically amplify the oxidation current of the probe. In order to examine the effects of substituting group on the binding interaction of carbaryl with DNA, the interaction of naphthalene or α-naphthol with DNA was also studied by square wave voltammetry (SWV). The values of binding constant Kb of the three compounds to DNA are determined, which fall in the range of (0.2?×?105) to (1.3?×?105)?M?1. The correlation suggests that the functional groups may play an important role in the DNA/analyte competition binding interaction. We demonstrated that it is conducive to the combination of small molecules and DNA when the functional groups are hydrophobic and have the lone-pair electrons as the electron donor. Furthermore, UV-absorption and fluorescence intensity of Ru-dppz decreases in the presence of carbaryl. These characteristics strongly support the intercalation of carbaryl into double-stranded DNA. 相似文献
The environmental effects on the structural and photophysical properties of [Ru(L)2(dppz)]2+ complexes (L=bpy=2,2′‐bipyridine, phen=1,10‐phenanthroline, tap=1,4,5,8‐tetraazaphenanthrene; dppz=dipyrido[3,3‐a:2′,3′‐c]phenazine), used as DNA intercalators, have been studied by means of DFT, time‐dependent DFT, and quantum mechanics/molecular mechanics calculations. The electronic characteristics of the low‐lying triplet excited states in water, acetonitrile, and DNA have been investigated to decipher the influence of the environment on the luminescent behavior of this class of molecules. The lowest triplet intra‐ligand (IL) excited state calculated at λ≈800 nm for the three complexes and localized on the dppz ligand is not very sensitive to the environment and is available for electron transfer from a guanine nucleobase. Whereas the lowest triplet metal‐to‐ligand charge‐transfer (3MLCT) states remain localized on the ancillary ligand (tap) in [Ru(tap)2(dppz)]2+, regardless of the environment, their character is drastically modified in the other complexes [Ru(phen)2(dppz)]2+ and [Ru(bpy)2(dppz)]2+ upon going from acetonitrile (MLCTdppz/phen or MLCTdppz/bpy) to water (MLCTdppz) and DNA (MLCTphen and MLCTbpy). The change in the character of the low‐lying 3MLCT states accompanying nuclear relaxation in the excited state controls the emissive properties of the complexes in water, acetonitrile, and DNA. The light‐switching effect has been rationalized on the basis of environment‐induced control of the electronic density distributed in the lowest triplet excited states. 相似文献
Abstract An electrochemiluminescence (ECL) method for reduced nicotinamide adenine dinucleotide (NADH) was proposed by immobilizing tris(2,2′‐bipyridyl) ruthenium(II) (Ru(bpy)32+) in multiwall carbon nanotubes (MWCNTs)/Nafion composite membrane that was formed on glassy carbon electrode surface. The electrochemical and ECL behaviors of the immobilized Ru(bpy)32+ were investigated. The cyclic votammogram of the modified electrode in pH 7.0 phosphate buffer solution showed a couple of redox peaks at +1190 and +1060 mV at 100 mV/s. The composite film had a more open structure and a large surface area allowing faster diffusion of Ru(bpy)32+. The presence of MWCNTs resulted in the improved ECL sensitivity and longer‐term stability of the modified electrode. The modified electrode showed a linear response to NADH in the concentration range of 1.0×10?6 to 1.6×10?5 M with a detection limit of 8.2×10?7 M. 相似文献
A novel [Ru(bpy)2(dcbpy)NHS] labeling/aptamer‐based biosensor combined with gold nanoparticle amplification for the determination of lysozyme with an electrochemiluminescence (ECL) method is presented. In this work, an aptamer, an ECL probe, gold nanoparticle amplification, and competition assay are the main protocols employed in ECL detection. With all the protocols used, an original biosensor coupled with an aptamer and [Ru(bpy)2(dcbpy)NHS] has been prepared. Its high selectivity and sensitivity are the main advantages over other traditional [Ru(bpy)3]2+ biosensors. The electrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM) characterization illustrate that this biosensor is fabricated successfully. Finally, the biosensor was applied to a displacement assay in different concentrations of lysozyme solution, and an ultrasensitive ECL signal was obtained. The ECL intensity decreased proportionally to the lysozyme concentration over the range 1.0×10?13–1.0×10?8 mol L?1 with a detection limit of 1.0×10?13 mol L?1. This strategy for the aptasensor opens a rapid, selective, and sensitive route for the detection of lysozyme and potentially other proteins. 相似文献
Subtle ligand modifications on RuII-polypyridyl complexes may result in different excited-state characteristics, which provides the opportunity to tune their photo-physicochemical properties and subsequently change their biological functions. Here, a DNA-targeting RuII-polypyridyl complex (named Ru1 ) with highly photosensitizing 3IL (intraligand) excited state was designed based on a classical DNA-intercalator [Ru(bpy)2(dppz)] ⋅ 2 PF6 by incorporation of the dppz (dipyrido[3,2-a:2′,3′-c]phenazine) ligand tethered with a pyrenyl group, which has four orders of magnitude higher potency than the model complex [Ru(bpy)2(dppz)] ⋅ 2 PF6 upon light irradiation. This study provides a facile strategy for the design of organelle-targeting RuII-polypyridyl complexes with dramatically improved photobiological activity. 相似文献
Many cathodic electrochemiluminescence (ECL) systems require very negative potentials; it is difficult to achieve stable cathodic ECL in aqueous solutions because of hydrogen evolution and instability of intermediates. In this study, tricresyl phosphate-based carbon paste electrode (CPE) was used to achieve cathodic ECL. It exhibits no obvious hydrogen evolution even at a potential up to ?1.6 V and dramatically stabilizes electrogenerated [Ru(bpy)3]+. Therefore, a reversible wave of [Ru(bpy)3]2+/1+ in aqueous solutions at carbon electrode has been observed for the first time, and cathodic ECL of [Ru(bpy)3]2+/S2O82? has been achieved. Under the optimum conditions, the plots of the ECL versus the concentration of S2O82? are linear in the range of 10?6 to 10?2 M with the detection limit of 3.98?×?10?7 M. Common anions have no effect on the ECL intensity of the [Ru(bpy)3]2+/S2O82? system. Since CPEs have been widely used, CPEs with high hydrogen evolution potential are versatile platforms for electrochemical study and cathodic ECL study. 相似文献
A novel polypyridine ligand, dipyrido[3,2‐a:2′,3′‐c]phenazine‐11‐carboxylic acid methyl ester (=dppz‐11‐CO2Me), and its ruthenium(II) complex, [Ru(bpy)2(dppz‐11‐CO2Me)]2+ ( 1 ), were synthesized and characterized. The binding properties of this complex to calf‐thymus DNA (CT‐DNA) were investigated by different spectrophotometric methods and viscosity measurements. The results suggest that the complex binds to DNA in an intercalative mode and serves as a molecular ‘light switch’ for DNA. When irradiated at 365 nm, the complex 1 promoted the photocleavage of plasmid pBR‐322 DNA. 相似文献
Recognition and regulation of G‐quadruplex nucleic acid structures is an important goal for the development of chemical tools and medicinal agents. The addition of a bromo‐substituent to the dipyridylphenazine (dppz) ligands in the photophysical “light switch”, [Ru(bpy)2dppz]2+, and the photochemical “light switch”, [Ru(bpy)2dmdppz]2+, creates compounds with increased selectivity for an intermolecular parallel G‐quadruplex and the mixed‐hybrid G‐quadruplex, respectively. When [Ru(bpy)2dppz‐Br]2+ and [Ru(bpy)2dmdppz‐Br]2+ are incubated with the G‐quadruplexes, they have a stabilizing effect on the DNA structures. Activation of [Ru(bpy)2dmdppz‐Br]2+ with light results in covalent adduct formation with the DNA. These complexes demonstrate that subtle chemical modifications of RuII complexes can alter G‐quadruplex selectivity, and could be useful for the rational design of in vivo G‐quadruplex probes. 相似文献
Electrochemiluminescence (ECL) and electrochemistry are reported for a heterometallic soft salt, [Ru(dtbubpy)3][Ir(ppy)2(CN)2]2 ( [Ir][Ru][Ir] ), consisting of a 2:1 ratio of complementary charged Ru and Ir complexes possessing two different emission colors. The [Ru]2+ and [Ir]? moieties in the [Ir][Ru][Ir] greatly reduce the energy required to produce ECL. Though ECL intensity in the annihilation path was enhanced 18× relative to that of [Ru(bpy)3]2+, ECL in the co‐reactant path with tri‐n‐propylamine was enhanced a further 4×. Spooling spectroscopy gives insight into ECL mechanisms: the unique light emission at 634 nm is due to the [Ru]2+* excited state and no [Ir]?* was generated in either route. Overall, the soft salt system is anticipated to be attractive and suitable for the development of efficient and low‐energy‐cost ECL detection systems. 相似文献
The cationic luminescence probe, tris(2,2′-bipyridyl)ruthenium(II) complex ([Ru(bpy)3]2+), was incorporated into laponite-modified glassy carbon electrode (GCE) via two strategies, namely, the adsorption and intercalation methods. These two incorporation methods resulted in different microenvironment for the immobilized [Ru(bpy)3]2+ within laponite as well as the different host–guest and guest–guest interactions. Herein, cyclic voltammetry and electrochemiluminescence (ECL) were innovatively performed to monitor the interactions. Tripropylamine (TPA) was used as coreactant in the electrochemical and ECL system. 相似文献
An ultrasensitive electrogenerated chemiluminescence (ECL) immunoassay was proposed by using magnetic nanobeads (MNBs) as the carrier of ECL labels for ECL emission amplification. Carcinoembryonic antigen (CEA) and MNBs were initially immobilized on a platform in 1 : 1 molar ratio via sandwich immunoreaction. Subsequently, the MNBs were released from the platform and labeled with Ru(bpy)32+ species. After the MNBs with Ru(bpy)32+ were immobilized on an Au electrode, ECL of the Ru(bpy)32+ was measured for CEA determination. A linear relation between the ECL intensity and CEA concentration was obtained in a range of 1×10?14 to 3×10?13 mol/L (2.0 to 60 pg/mL) with a limit of detection of 8.0×10?15 mol/L (1.6 pg/mL). 相似文献
Photoluminescence (PL) and electrochemiluminescence (ECL) detection techniques are highly sensitive and widely used methods for clinical diagnostics and analytical biotechnology. In this work, a unique ruthenium(II) complex, [Ru(bpy)2(DNBSO-bpy)](PF6)2 (bpy: 2,2′-bipyridine; DNBSO-bpy: 2,4-dinitrobenzenesulfonate of 4-(4-hydroxyphenyl)-2,2′-bipyridine), has been designed and synthesized as a highly sensitive and selective PL and ECL dual-signaling probe for the recognition and detection of bio-thiols in aqueous media. As a thiol-responsive probe, the complex can specifically and rapidly react with bio-thiols in aqueous solutions to yield a bipyridine-Ru(II) complex derivative, [Ru(bpy)2(HP-bpy)]2+ (HP-bpy: 4-(4-hydroxyphenyl)-2,2′-bipyridine), accompanied by the remarkable PL and ECL enhancements. The complex was used as a probe for the PL and ECL detections of cysteine (Cys) and glutathione (GSH) in aqueous solutions. The dose-dependent PL and ECL enhancements showed good linear relationships against the Cys/GSH concentrations with the detection limits at nano-molar concentration level. Moreover, the complex-loaded HeLa cells were prepared for PL imaging of the endogenous intracellular thiols. The results demonstrated the practical utility of the complex as a cell-membrane permeable probe for PL imaging detection of bio-thiols in living cells. 相似文献
Two ruthenium complexes [Ru(MeIm)4(bpy)]2+ (Ru1, MeIm = 1-methylimidazole, bpy = 2,2′-bipyridine) and [Ru(Im)4(bpy)]2+ (Ru2, Im = imidazole) with the same PF6? counter-ion but different lipophilicities were synthesized and characterized and as potent anticancer agents. The relationships between cellular uptake, localization and molecular action mechanisms of these complexes were elucidated. The results showed that Ru1 with higher logPo/w exhibited faster cellular uptake rates, but lower anticancer activity than Ru2. In addition, Ru1 predominantly accumulated in the mitochondria and cytoplasm, and induced G0/G1 cell cycle arrest, whereas the more hydrophilic Ru2 tended to localize and accumulate in the cell nucleus and mitochondria. Further mechanism studies indicated that Ru2 caused cell cycle arrest at S phase by regulating cell cycle related proteins and induced apoptosis in A549 cells through DNA damage, cellular ROS accumulation, activation of the caspase pathway and mitochondrial dysfunction. 相似文献
Two novel chiral ruthenium(II) complexes, Δ‐[Ru(bpy)2(dmppd)]2+ and Λ‐[Ru(bpy)2(dmppd)]2+ (dmppd = 10,12‐dimethylpteridino[6,7‐f] [1,10]phenanthroline‐11,13(10H,12H)‐dione, bpy = 2,2′‐bipyridine), were synthesized and characterized by elemental analysis, 1H‐NMR and ES‐MS. The DNA‐binding behaviors of both complexes were studied by UV/VIS absorption titration, competitive binding experiments, viscosity measurements, thermal DNA denaturation, and circular‐dichroism spectra. The results indicate that both chiral complexes bind to calf‐thymus DNA in an intercalative mode, and the Δ enantiomer shows larger DNA affinity than the Λ enantiomer does. Theoretical‐calculation studies for the DNA‐binding behaviors of these complexes were carried out by the density‐functional‐theory method. The mechanism involved in the regulating and controlling of the DNA‐binding abilities of the complexes was further explored by the comparative studies of [Ru(bpy)2(dmppd)]2+ and of its parent complex [Ru(bpy)2(ppd)]2+ (ppd = pteridino[6,7‐f] [1,10]phenanthroline‐11,13 (10H,12H)‐dione). 相似文献
Tris(2,2′‐bipyridine)ruthenium(II) ([Ru(bpy)3]2+) is one of the most extensively studied and used electrochemiluminescent (ECL) compounds owing to its superior properties, which include high sensitivity and stability under moderate conditions in aqueous solution. In this paper we present a simple method for the preparation of [Ru(bpy)3]2+‐containing microstructures based on electrostatic assembly. The formation of such microstructures occurs in a single process by direct mixing of aqueous solutions of [Ru(bpy)3]Cl2 and K3[Fe(CN)6] at room temperature. The electrostatic interactions between [Ru(bpy)3]2+ cations and [Fe(CN)6]3? anions cause them to assemble into the resulting microstructures. Both the molar ratio and concentration of reactants were found to have strong influences on the formation of these microstructures. Most importantly, the resulting [Ru(bpy)3]2+‐containing microstructures exhibit excellent ECL behavior and, therefore, hold great promise for solid‐state ECL detection in capillary electrophoresis (CE) or CE microchips. 相似文献
The authors describe an electrochemiluminescence (ECL) based aptasensor for the pesticide aldicarb. The method is based on effective ECL energy transfer that occurs between the ruthenium(II) bipyridyl complex [referred to as Ru(bpy)32+] and gold nanoparticles (AuNPs). More specifically, multiwalled carbon nanotubes were modified with dendritic poly(L-arginine) labeled with Ru(bpy)32+, and the aptamers were taggedd with AuNPs. In the absence of aldicarb, the ECL emitted by Ru(bpy)32+ is enhanced by AuNPs under peak wavelength at at a wavelength of 610 nm. In the presence of aldicarb, the capture and competitive binding of aldicarb to the DNA aptamers causes their separation from the DPA6/Ru(bpy)32+/MWCNT. As a result, ECL intensity decreases linearly with increasing aldicarb concentrations in the range between 40 pM and 4 nM, with a detection limit of 9.6 pM. This aptamer switch is highly sensitive, selective and inexpensive. Conceivably, it can be adapted to formats for the determination of other pesticide residues by using different DNA aptamers.
Graphical abstract Schematic of the procedure for aptamer-based detection of aldicarb using the ECL signal of the Ru(bpy)32+ amplified by gold nanoparticles. This assay has high sensitivity, good selectivity, and low cost. It can presumably be transferred to other pesticide detection schemes.
Electrochemiluminescence (ECL) of tris(2,2′‐bipyridine)ruthenium, Ru(bpy)32+ in the presence of various co‐reactants, such as tripropylamine (TPA), oxalate ion (C2O42?), ascorbic acid (H2A) and dehydroascorbic acid (DHA), were investigated under ultrasound irradiation. In sono‐ECL experiments, an indium‐thin‐oxide (ITO) was used as working electrode, and a titanium tipped sonic horn probe (diameter 2 mm) which operated at a frequency of 20 kHz was set in the front of the ITO electrode. Under the ultrasound irradiation, ECL signals were found to be significantly enhanced when TPA and C2O42? were used as co‐reactants, only slightly enhanced in Ru(bpy)32+/DHA system, but total quenched in Ru(bpy)32+/H2A system. The difference of Ru(bpy)32+ ECL behaviors for various co‐reactant could to be due to the different kinetics of catalytic reactions associated in ECL schemes. ECL quenching effect observed in Ru(bpy)32+/H2A system was suggested to be due to electron transfer (ET) route between the excited state *Ru(bpy)32+ and ascorbate anion HA? diffused from the bulk solution, where the diffusional HA? species served as electron donor. The effect becomes more pronounced upon sonication because the effective collision frequency between *Ru(bpy)32+ and HA? would be significantly increased by the enhanced mass transport effect of ultrasound. 相似文献
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