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1.
A fluorescence and absorption chemosensor (SAAT) based on 5-(hydroxymethyl)-salicylaldehyde (SA) and o-aminothiophenol (AT) was designed and synthesized. SAAT in DMSO–HEPES (20.0 mM, v/v, 1:99, pH = 7.0) solution shows a highly selective and sensitive absorption and an ‘on–off’ fluorescence response to Cu2+ ions in aqueous solutions over all other competitive metal ions including Na+, Ag+, Ba2+, Ca2+, Cd2+, Mg2+, Zn2+, Cr3+, Al3+, Hg2+, K+, Mn2+, Ni2+, Sr2+, Tb3+ and Co2+. SAAT exhibits ratiometric absorption sensing ability for Cu2+ ions. Importantly, SAAT also can sense Cu2+ ions using fluorescence quenching, the fluorescence intensity of SAAT showed a good linear relationship with Cu2+ concentration, and the detection limit of Cu2+ was 0.34 μM. The results of Job's plot, Benesi–Hildebrand plot, mass spectra, and density functional theory calculations confirmed that the selective absorption and fluorescence response were attributed to the formation of a 1:1 complex between SAAT and Cu2+. SAAT in test film could identify Cu2+ in water samples using the intuitive fluorescence colour change under a UV lamp. SAAT has great application value as a selective and sensitive chemosensor to discriminate and detect Cu2+ ions. 相似文献
2.
Araghni Bhattacharya Satyajit Mahata Ashutosh Bandyopadhyay Biman B. Mandal Vadivelu Manivannan 《Luminescence》2022,37(6):883-891
The 2,4,5-tris(2-pyridyl)imidazole ( L ) molecule has been evaluated as a probe for dual sensing of Hg2+ and Cu2+ ions in EtOH/HEPES buffer medium (5 mM, pH = 7.34, 1:1, v/v). Probe L shows a good sensitive and selective turn-off response in the presence of both Hg2+ and Cu2+ ions, which is comprehensible under long UV light. The probe can detect Cu2+ ion in the pH range 3–11 and Hg2+ ion in pH 6–8. The limit of detection for Cu2+ (0.77 μM) is well under the allowable limit prescribed by the United States Environmental Protection Agency. Two metal (Cu2+/Hg2+) ions are needed per L for complete fluorescence quenching. The probe shows marked reversibility on treatment with Na2EDTA, making the protocol more economical for practical purposes. Paper strip coated with the L solution of EtOH can detect the presence of Cu2+ and Hg2+ ions in the sample using visible quenching of the fluorescence intensity. Density functional theory–time-dependent density functional theory (DFT–TDDFT) calculations support experimental observations, and d-orbitals of Cu2+/Hg2+ provide a nonradiative decay pathway. Cell imaging study using HDF and MDA-MB-231 cells also supported the viability of L in detecting Cu2+ and Hg2+ ions in living cells. 相似文献
3.
Mikoshiba K 《Biochemical and biophysical research communications》2008,369(1):57-61
The red fluorescent protein, DsRed, and a few of its mutants have been shown to bind copper ions resulting in quenching of its fluorescence. The response to Cu2+ is rapid, selective, and reversible upon addition of a copper chelator. DsRed has been employed as an in vitro probe for Cu2+ determination by us and other groups. It is also envisioned that DsRed can serve as an intracellular genetically encoded indicator of Cu2+ concentration, and can be targeted to desired subcellular locations for Cu2+ determination. However, no information has been reported yet regarding the mechanism of the fluorescence quenching of DsRed in the presence of Cu2+. In this work, we have performed spectroscopic investigations to determine the mechanism of quenching of DsRed fluorescence in the presence of Cu2+. We have studied the effect of Cu2+ addition on two representative mutants of DsRed, specifically, DsRed-Monomer and DsRed-Express. Both proteins bind Cu2+ with micromolar affinities. Stern-Volmer plots generated at different temperatures indicate a static quenching process in the case of both proteins in the presence of Cu2+. This mechanism was further studied using absorption spectroscopy. Stern-Volmer constants and quenching rate constants support the observation of static quenching in DsRed in the presence of Cu2+. Circular dichroism (CD)-spectroscopic studies revealed no effect of Cu2+-binding on the secondary structure or conformation of the protein. The effect of pH changes on the quenching of DsRed fluorescence in the presence of copper resulted in pKa values indicative of histidine and cysteine residue involvement in Cu2+-binding. 相似文献
4.
Fluorescent proteins show fluorescence quenching by specific metal ions, which can be applied towards metal biosensing applications. In order to develop metal-biosensor, we performed spectroscopic analysis of the fluorescence quenching of fluorescent protein AmCyan and mOrange2 by various metal ions. The fluorescence intensity of AmCyan was reduced to 48.54% by Co2+ and 67.77% by Zn2+; Cu2+ reduced the fluorescence emission of AmCyan to 19.30% of its maximum. The fluorescence intensity of mOrange2 was quenched by only Cu2+, to 11.48% of its maximum. When analyzed by Langmuir equation, dissociation constants for AmCyan and mOrange2 were 56.10 and 21.46 µM, respectively. The Cu2+ quenching of AmCyan and mOrange2 were reversible upon treatment with the metal chelator EDTA, indicating that the metal ions were located on the protein surface. Their model structures suggest that AmCyan and mOrange2 have novel metal-binding sites. 相似文献
5.
V. N. Danilevich V. V. Sorokin Ya. P. Moiseev S. V. Sizova 《Doklady. Biochemistry and biophysics》2018,479(1):118-122
The patterns of formation of RNA nanoparticles (NPs) during thermal cycling of bacterial total tRNA in the presence of cations Ca2+, Mn2+, Ni2+, Zn2+, Co2+, and Cu2+ were studied. The optimal conditions for the production of NPs were found, and it was revealed that their size depends on the ratio of the concentrations of Me2+ and tRNA. The concentration of reagents for obtaining NPs of small size (from 5 to 100 nm) was selected. It was shown that tRNA-based nanoparticles can comprise short (20–50 nt) ribooligonucleotides, including aptamers and siRNAs. The stability of NPs during storage in buffer solutions of various composition was studied. It was found that the initial suspensions of NPs are quite stable, but they are rapidly destroyed in PBS buffer (pH 7.4). A simple and effective stabilizer (polyarginine) was found, the additives of which ensure the preservation of nanoparticles in PBS buffer for more than 5 h. Nanoparticles modified with the stabilizer are resistant to blood serum nucleases and can be used for transfection. 相似文献
6.
Naked eye sensing of toxic metal ions in aqueous medium using thiophene‐based ligands and its application in living cells
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Duraisamy Udhayakumari Sivalingam Suganya Sivan Velmathi Davoodbasha MubarakAli 《Journal of molecular recognition : JMR》2014,27(3):151-159
Thiophene‐based diimine (R1) and monoimine (R2) were synthesized in a single step, and their cation binding affinity was tested using colorimetric and UV–vis spectral studies. R1 selectively shows a colorimetric turn‐on response for Pb2+, Hg2+ ions and colorimetric turn‐off with Sn2+ ions, and R2 shows visual response for Cu2+ and Hg2+ over other examined metal ions in aqueous medium. R1 forms 1:1 complex with Pb2+, Hg2+, and Sn2+ and exhibits fluorescence quenching, whereas R2 shows 2:1 complex with Hg2+, Cu2+ and shows fluorescence enhancement. The structural and electronic properties of the sensors and their metal complexes were also investigated using Density Functional Theory calculations. R2 was also successfully demonstrated as a fluorescent probe for detecting Cu2+ ions in living cells. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
7.
Na'il Saleh 《Luminescence》2009,24(1):30-34
A water‐soluble, high‐output fluorescent sensor, based on a lumazine ligand with a thiophene substituent for Cd2+, Hg2+ and Ag+ metal ions, is reported. The sensor displays fluorescence enhancement upon Cd2+ binding (log β = 2.79 ± 0.08) and fluorescence quenching by chelating with Ag+ and Hg2+ (log β = 4.31 ± 0.15 and 5.42 ± 0.1, respectively). The mechanism of quenching is static and occurs by formation of a ground‐state non‐fluorescent complex followed by rapid intersystem crossing. The value of the Stern–Volmer quenching rate constant (kq) by Ag+ ions is close to 6.71 × 1012 mol/L/s at 298 K. The thermodynamic parameters (ΔG, ΔH and ΔS) were also evaluated and indicated that the complexation process is spontaneous, exothermic and entropically favourable. The quantitative linear relationship between the softness values of Klopman (σK) or Ahrland (σA) and the experimental binding constants (β) being in the order of Hg2+ > Ag+ > Cd2+ suggests that soft–soft interactions are the key for the observed sensitivity and selectivity in the presence of other metal ions, such as: Pb2+, Ni2+, Mn2+, Cu2+, Co2+, Zn2+ and Mg2+ ions. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
8.
人血清白蛋白与金属离子作用的荧光光谱研究 总被引:27,自引:0,他引:27
通过金属离子对人血清白蛋白内源荧光的猝灭,探讨了金属离子Cu2+,Mn2+,Ni2+,Co2+,Cr3+等与人血清白蛋白的结合;基于Förster无辐射能量转移机理,得出了人血清白蛋白第一类Cu2+结合部位与214位色氨酸残基间的距离。 相似文献
9.
Extracellular synthesis of cuprous selenide nanospheres by a biological‐chemical coupling reduction process in an anaerobic microbial system
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Biosynthesis of metal nanoparticles represents a clean, eco‐friendly and sustainable “green chemistry” engineering. Lately, a number of metal selenides were successfully synthesized by biological methods. Here, cuprous selenide (Cu2Se) nanospheres were prepared under mild conditions by a novel biological‐chemical coupling reduction process. The simple process takes place between EDTA‐Cu and Na2SeO3 in presence of an alkaline solution containing NaBH4 and a selenite‐reducing bacteria, Pantoea agglomerans. It is noteworthy that the isolated Pantoea agglomerans and Cu+ ions, where the latter are obtained from reducing Cu2+ ions by NaBH4, play a key role, and Cu+ ions not only can promote the generation of Se2? ions as a catalyst, but also can react with Se2? ions to form Cu2Se. XRD pattern, SEM, and TEM images indicated that Cu2Se nanoparticles were tetragonal crystal structure and the nanospheres diameter were about 100 nm. EDX, UV–vis, and FTIR spectra show that the biosynthesized Cu2Se nanospheres are wrapped by protein and have a better stability. This work first proposes a new biosynthesis mechanism, and has important reference value for biological preparation of metal selenide nanomaterials. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1264–1270, 2016 相似文献
10.
Two new twinborn benzimidazole derivates ( L and A ), which bonded pyridine via the ester space on the opposite and adjacent positions of the benzene ring of benzimidazole respectively, were designed and synthesized. Compound L displayed fluorescence quenching response only towards copper(II) ions (Cu2+) in acetonitrile solution with high selectivity and sensitivity. However, compound A presented ‘on–off’ fluorescence response towards a wide range of metal ions to different degrees and did not have selectivity. Furthermore, compound L formed a 1:1 complex with Cu2+ and the binding constant between sensor L and Cu2+ was high at 6.02 × 104 M?1. Job's plot, mass spectra, IR spectra, 1H‐NMR titration and density functional theory (DFT) calculations demonstrated the formation of a 1:1 complex between L and Cu2+. Chemosensor L displayed a low limit of detection (3.05 × 10?6 M) and fast response time (15 s) to Cu2+. The Stern–Volmer analysis illustrated that the fluorescence quenching agreed with the static quenching mode. In addition, the obvious difference of L within HepG2 cells in the presence and absence of Cu2+ indicated L had the recognition capability for Cu2+ in living cells. 相似文献
11.
The divalent metal ions Cu2+, Co2+, Mn2+, and Zn2+ form complexes with the fluorescent etheno analogs of the adenine nucleotides. The fluorescence intensity is thereby diminished. The binding strength of the metals to etheno-adenosine triphosphate is higher than to etheno-adenosine di- and monophosphate. The quenching effect of the divalent metal ions can be exploited as a simple routine activity measurement for various kinases and phosphohydrolases. 相似文献
12.
Amit Jaiswal Pallab Sanpui Arun Chattopadhyay Siddhartha Sankar Ghosh 《Plasmonics (Norwell, Mass.)》2011,6(1):125-132
Water dispersible zinc sulfide quantum dots (ZnS QDs) with an average diameter of 2.9 nm were synthesized in an environment
friendly method using chitosan as stabilizing agent. These nanocrystals displayed characteristic absorption and emission spectra
having an absorbance edge at 300 nm and emission maxima (λ
emission) at 427 nm. Citrate-capped silver nanoparticles (Ag NPs) of ca. 37-nm diameter were prepared by modified Turkevich process.
The fluorescence of ZnS QDs was significantly quenched in presence of Ag NPs in a concentration-dependent manner with K
sv value of 9 × 109 M−1. The quenching mechanism was analyzed using Stern–Volmer plot which indicated mixed nature of quenching. Static mechanism
was evident from the formation of electrostatic complex between positively charged ZnS QDs and negatively charged Ag NPs as
confirmed by absorbance study. Due to excellent overlap between ZnS QDs emission and surface plasmon resonance band of Ag
NPs, the role of energy transfer process as an additional quenching mechanism was investigated by time-resolved fluorescence
measurements. Time-correlated single-photon counting study demonstrated decrease in average lifetime of ZnS QDs fluorescence
in presence of Ag NPs. The corresponding F?rster distance for the present QD–NP pair was calculated to be 18.4 nm. 相似文献
13.
Study of fluorescence quenching of mercaptosuccinic acid‐capped CdS quantum dots in the presence of some heavy metal ions and its application to Hg(II) ion determination
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In this study, CdS quantum dots (QDs) capped with mercaptosuccinic acid (MSA) were prepared in one step. The size, shape, component and spectral properties of MSA‐capped CdS QDs were characterized by transmission electron microscopy (TEM), photoluminescence (PL) and infrared (IR) spectrometry. The results showed that the prepared QDs with an average diameter of 6 nm have favorable fluorescence, which is greatly influenced by the pH of the environment. The interaction of some heavy metal ions including Ag+, Hg2+, Cu2+, Ni2+ and Co2+ with MSA‐capped CdS QDs was investigated in different buffering pH media. Based on the fluorescence quenching of the QDs in the presence of each of the metal ions, the feasibility of their determinations was examined according to the Stern–Volmer equation. The investigations showed that Hg(II) ions can be determined in the presence of many co‐existing metal ions at a buffering pH of 5. This method was satisfactorily applied to the measurement of Hg(II) ions in some environmental samples. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
14.
Huang L Hou FP Xi P Bai D Xu M Li Z Xie G Shi Y Liu H Zeng Z 《Journal of inorganic biochemistry》2011,105(6):800-805
A new fluorescent probe 1, N-(Rhodamine-6G)lactam-hydrazinecarbothioamide, was synthesized as a fluorescent and colorimetric chemodosimeter in aqueous solution for Cu2+. Following Cu2+-promoted ring opening, redox and hydrolysis reactions, comparable amplifications of absorption and fluorescence signals were observed upon addition of Cu2+; this suggests that chemodosimeter 1 effectively avoided the fluorescence quenching caused by the paramagnetic nature of Cu2+. Importantly, 1 can selectively recognize Cu2+ in aqueous media in the presence of other trace metal ions in organisms, abundant cellular cations and the prevalent toxic metal ions in the environment with high sensitivity (detection limit < 3 ppb) and a rapid response time (< 2 min). In addition, the biological imaging study has demonstrated that 1 can detect Cu2+ in the living cells. 相似文献
15.
Bovine carbonic anhydrase shows an intrinsic fluorescence which results from tryptophans located in different microenvironments. It is possible to attribute the whole fluorescence to at least two types of tryptophan.This fluorescence is differently affected by the binding of different metals. In fact while Zn2+ causes an increase of the fluorescence yield, the binding of Co2+, Cu2+ and Hg2+ is followed by a quenching of the fluorescence. The quenching is about 40% for the cobalt, 80% for the copper and 60% for the mercury derivative. The binding of Cu2+ and Hg2+ induces also a change in the shape of the fluorescence emission spectrum. This fact suggests a different influence of the metals on the various types of tryptophan.The fluorescence quenching induced by iodide which can bind to the metal and act as a fluorescence perturbing agent is also indicative of the presence of different tryptophans. 相似文献
16.
Titrations of the quenching of the tryptophan fluorescence of yeast hexokinase isozymes P-I and P-II by Mg2+, Mn2+, Ca2+, Cd2+, and Zn2+ ions and by glucose in the presence of each of these ions (10mM) were performed at pH 5.5 and 6.5 at 20°C. At the higher pH there was a reversal of the type of glucose-binding cooperativity for P-II from negative to positive when either Mn2+ or Ca2+ was present in the buffered isozyme solution before the glucose titration, whereas Mg2+ caused the glucose binding to become noncooperative. Zn2+ and Cd2+ decreased the glucose quenching of P-II fluorescence drastically at pH 5.5, from a value of 15% in buffer to only 4%. Thus, only these two ions, of the five studied, cause the conformation change that results in quenching of the glucose-quenchable cleft tryptophan of P-II. Glucose binding to the P-I isozyme exhibited positive cooperativity in the presence of either Ca2+, Mg2+, or Mn2+, as well as in buffer alone, at both pH's. At the lower pH, Ca2+ enhanced the efficiency of glucose quenching of P-I fluorescence several-fold, while Mn2+ increased it only about 40% and Mg2+ not at all. Further, Ca2+ raised the degree of cooperativity (Hill coefficient) of glucose binding to P-I at this pH from the value of 1.42 in buffer and in the presence of Mg2+ and Mn2+ to 1.94, i.e., almost up to the highest possible value, 2, for dimeric hexokinase. However, at pH 6.5 the Ca2+ effect on the cooperativity was negligible, while Mg2+ and Mn2+ decreased the coefficient from 1.6 in buffer to about 1.4. The biological implications of these diverse metal ion effects are discussed. 相似文献
17.
A new Schiff base as a turn‐off fluorescent sensor for Cu2+ and its photophysical properties
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A new Schiff base receptor 1 was synthesized and its photophysical properties were investigated by absorption, emission and excitation techniques. Furthermore, its chromogenic and fluorogenic sensing abilities towards various metal ions were examined. Receptor 1 selectively detects Cu2+ ion through fluorescence quenching and detection was not inhibited in the presence of other metal ions. From fluorescence titration, the limit of detection of receptor 1 as a fluorescent ‘turn‐off’ sensor for the analysis of Cu2+ was estimated to be 0.35 μM. 相似文献
18.
Tasawan Keawwangchai Banchob Wanno Nongnit Morakot Somchai Keawwangchai 《Journal of molecular modeling》2013,19(10):4239-4249
Two BODIPY derivatives for Cu2+ ion chemosensors containing 4-[2-(diethylamino)-2-oxoethoxy]phenyl (BDP1) and 3,4-bis[2-(diethylamino)-2-oxoethoxy]phenyl (BDP2) were synthesized by coupling appropriate N,N-diethyl-2-(4-formylphenoxy)acetamide and 2,4-dimethylpyrrole moieties in the presence of trifluoroacetic acid and anhydrous dichloromethane at room temperature. The binding abilities between these chemosensors and 50 equivalents of Na+, K+, Ag+, Ca2+, Fe2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ ions were studied using UV-vis and fluorescence spectrophotometry. The results show that, compared to other ions, both the UV-vis absorption and fluorescence emission intensity of BDP2 decreased dramatically when Cu2+ ion was added. To explain this behavior, ab initio quantum chemical calculations were performed using correlated second-order Møller-Plesset perturbation theory (MP2/LanL2DZ). The calculated orbital energies indicated that the decrease in UV-vis absorption intensity and the quenching of fluorescene emission were due to the single-electron reduction of Cu2+ to Cu+ ion. Figure
Optimized structure, fluorescent spectra, frontier orbital energy diagrams and electron-transfer paths in receptor BDP2 before and after attachment to Cu2+ ion 相似文献
19.
The authors report that a marine Shewanella sp. CNZ-1 is capable of producing Au NPs under various conditions. Results showed that initial concentration of Au(III), pH values and electron donors affected nucleation of Au NPs by CNZ-1, resulting in different apparent color of the as-obtained bio-Au NPs, which were further characterized by UV-Vis, TEM, XRD, and XPS analyses. Mechanism studies revealed that Au(III) was first reduced to Au(I) and eventually reduced to EPS-coated Au0 NPs. FTIR and FEEM analyses revealed that some amides and humic acid-like matters were involved in the production of bio-Au NPs through CNZ-1 cells. In addition, the authors also found that the catalytic activity of bio-Au NPs for 4-nitrophenol (4-NP) reduction could be enhanced by various metal ions (Ca2+, Cu2+, Co2+, Fe2+, Fe3+, Ni2+, Sr2+, and Cr3+) and metal oxides (Fe3O4, Al2O3, and SiO2), which is beneficial for their further practical application. The maximum zero-order rate constant k 1 and first-order rate constant k2 of all metal ions/oxides supplemented systems can reach 99.65 mg/(L.min) and 2.419 min−1, which are 11.3- and 12.6-fold higher than that of control systems, respectively. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2727, 2019. 相似文献
20.
Metal ions such as Zn2+ and Cu2+ can mediate interactions between copolypeptides (Glux, Tyry)n and polynucleotides. CD data show that these ternary complexes are characterized by an unstacking of nucleic acid bases, while the polypeptide adopts an α-helical conformation as observed in the two binary complexes polynucleotide–cation and polypeptide–cation. Fluorescence studies demonstrate that tyrosyl side chains interact with nucleic acid bases in the ternary complexes, leading to a quenching of tyrosine fluorescence. 相似文献