The fluorescence of terbium (Ⅲ) was enhanced by about three orders of magnitude in the presence of trimellitic acid (benzene-1, 2, 4-tricarboxylic acid (TLA)) in aqueous solution at pH 6. The fluorescence inten...The fluorescence of terbium (Ⅲ) was enhanced by about three orders of magnitude in the presence of trimellitic acid (benzene-1, 2, 4-tricarboxylic acid (TLA)) in aqueous solution at pH 6. The fluorescence intensity could be greatly increased when the system of Tb^3+-TLA was treated with La^3+ (or Gd^3+) and TritonX- 100. The addition of La^3+ (or Gd^3+) enhanees the fluorescence of the system by about two orders of magnitude due to cofluorescenee, and the TritonX-100 micellar medium plays an important role for stabilization of the system. Both the intermolecular energy transfer mode and intramolecular energy transfer mode are responsible for the mechanism of fluorescence enhancement. In the optimum condi- tions, the fluorescence intensity is a linear function of Tb3~ concentration in the range of 7.8 × 10^-9-3.6 × 10^4 mol/L for the system Tb^3+-La^3+-TLA and 1.0 × 10^-8-4.7 × 10^-5 mol/L for the system Tb^3+-Gd^3+-TLA, and the limits of detection are 4.6 × 10^-10 mol/L and 6.0 × 10^-10 mol/L, respectively.展开更多
The spectral properties of trivalent erbium ions(Er^3+) are systematically studied in a melt-quenched germanate glass(60 GeO2-20PbO-10BaO-10K2O-0.1Ag2O) containing silver(Ag) particles.Thermal treatment of the ...The spectral properties of trivalent erbium ions(Er^3+) are systematically studied in a melt-quenched germanate glass(60 GeO2-20PbO-10BaO-10K2O-0.1Ag2O) containing silver(Ag) particles.Thermal treatment of the material leads to the precipitation of Ag particles as observed by transmission electron microscopy and confirmed by absorption spectrum for the obvious surface plasmon resonance peak of Ag particles.The fluorescence from Er^3+ in the 10-min-annealed sample with Ag particles is found to be 4.2 times enhanced compared with the unannealed sample excited by 488-nm Ar+ laser.A comparison is made between a spectral study performed on the unannealed Er^3+-doped sample and the one annealed for 20 min.The data of absorption cross section and Judd-Ofelt intensity parameters show the agreement between the two samples no matter whether there are Ag particles,indicating that the introduction of Ag particles by post-heat treatment has no effect on the crystal field environment of Er^3+ ions.The fluorescence enhancement is attributed to the surface plasmon oscillations of Ag particles in germanate glass.展开更多
Fluorescence and cofluorescence properties of Tb(Ⅲ) solid complexes werestudied using pyromellitic acid (PMA) as ligand and fluorescence inert ions as doping elements. Thecofluorescence enhancement, a result of ligan...Fluorescence and cofluorescence properties of Tb(Ⅲ) solid complexes werestudied using pyromellitic acid (PMA) as ligand and fluorescence inert ions as doping elements. Thecofluorescence enhancement, a result of ligand sensitized fluorescence, was observed in Tb(Ⅲ) solidcomplexes doped with fluorescent inert ions La(Ⅲ), Gd(Ⅲ), Ca(Ⅲ), and Sr(Ⅲ). The effect of thetype and content of doping elements on fluorescence enhancement was studied, and optimum conditionswere determined. The results show that Gd (La, Ca, Sr) has clear cofluorescence effect in solidcomplex Tb-M-PMA system, and in present work, rare earth complex fluorescent powder that emitsbright green fluorescence at ultraviolet excitation was obtained, which had potential application asfluorescent anti-counterfeit ink.展开更多
We fabricate nano-structural metal films to improve photoluminescence of perovskite films. When the perovskite film is placed on an ammonia-treated alumina film, stronger photoluminescence is found due to local field ...We fabricate nano-structural metal films to improve photoluminescence of perovskite films. When the perovskite film is placed on an ammonia-treated alumina film, stronger photoluminescence is found due to local field en- hancement effects. In addition, the oxide spacer layer between the metal (e.g., AI, Ag and Au) substrate and the perovskite film plays an important role. The simulations and experiments imply that the enhancement is related to surface plasmons of nano-structural metals.展开更多
We present a theoretical study of the influence of a single silver sphere on the fluorescence of radix angelica dahurica, which is a kind of traditional Chinese medicine. The enhancement factors of the excitation and ...We present a theoretical study of the influence of a single silver sphere on the fluorescence of radix angelica dahurica, which is a kind of traditional Chinese medicine. The enhancement factors of the excitation and the relaxation processes are deduced. The excitation can be enhanced more than 100 times at 315 nm. The enhancement factor of the emission can reach up to 9 at a center wavelength of 400 nm.展开更多
The study of fluorescence enhancement has attracted attention recently. For example, the sensitivity and selectivity of Eu-thenoyltrifluoroacetone (TTA)phenan-throline and Eu-diphacinone-ammonia systems in Triton X-...The study of fluorescence enhancement has attracted attention recently. For example, the sensitivity and selectivity of Eu-thenoyltrifluoroacetone (TTA)phenan-throline and Eu-diphacinone-ammonia systems in Triton X-100 micelles are increased by the addition of La;Gd;, Tb;, Lu;or Y;. The mechanism of this fluorescence(?)展开更多
[ Objective] The study aims at developing a novel fluorescence enhancement method to determine anionic surfactants. [ Method] Based on Fe3O4 @ PAA-RB fluorescent nanoparticles as fluorescent probes, we have developed ...[ Objective] The study aims at developing a novel fluorescence enhancement method to determine anionic surfactants. [ Method] Based on Fe3O4 @ PAA-RB fluorescent nanoparticles as fluorescent probes, we have developed a novel fluorescence enhancement method for the determi- nation of an anionic surfactant sodium dodecyl sulfate (SDS) through the gradual optimization of experiment conditions. [ Result] Under the opti- mum conditions, the extent of fluorescence enhancement is directly proportional to SDS concentration varying from 0.5 to 16.0 μmol/L, and the de- tection limit reaches 0.051 μmol/L. The relative standard deviation (RSD) for 4.0 μmol/L SDS is 3.3% ( n =6). The proposed method has been successfully applied to the determination of SDS in environmental water samples, with recovery of 96.3% -105.5%. E Conclusion] The novel fluo- rescence enhancement method is not only simple and rapid, but also has avoided using tedious solvent-extraction and toxic organic solvents.展开更多
A new theoretical equation for fluorescence enhancement effect between donor and acceptor has been introduced. By using-it we determined the binding constants and numbers of binding sites of five medicines, including ...A new theoretical equation for fluorescence enhancement effect between donor and acceptor has been introduced. By using-it we determined the binding constants and numbers of binding sites of five medicines, including chlorogenic acid, forsythiaside norfloxacin, Ciprofloxacin and fluorenone, to gamma-globulin.展开更多
Potential utilization of proteins for early detection and diagnosis of various diseases has drawn considerable interest in the development of protein-based detection techniques. Metal induced fluorescence enhancement ...Potential utilization of proteins for early detection and diagnosis of various diseases has drawn considerable interest in the development of protein-based detection techniques. Metal induced fluorescence enhancement offers the possibility of increasing the sensitivity of protein detection in clinical applications. We report the use of tunable plasmonic silver nanostructures for the fluorescence enhancement of a near-infrared (NIR) dye (Alexa Fluor 790). Extensive fluorescence enhan- cement of -2 orders of magnitude is obtained by the nanoscale control of the Ag nanostructure dimensions and interparticle distance. These Ag nanostructures also enhanced fluorescence from a dye with very high quantum yield (7.8 fold for Alexa Fluor 488, quantum efficiency (Qy) = 0.92). A combination of greatly enhanced excitation and an increased radiative decay rate, leading to an associated enhancement of the quantum efficiency leads to the large enhancement. These results show the potential of Ag nanostructures as metal induced fluorescence enhancement (MIFE) substrates for dyes in the NIR "biological window" as well as the visible region. Ag nanostructured arrays fabricated by colloidal lithography thus show great potential for NIR dye-based biosensing applications.展开更多
A novel fluorescent aqueous polyurethane emulsion DDAQ-TDI-PU was synthesized by blocking the anthraquinone moiety of 1,4-diamino-2,3-diphenoxyanthraquinone(DDAQ) into polyurethane chain using 2,4-tolylene diisocyan...A novel fluorescent aqueous polyurethane emulsion DDAQ-TDI-PU was synthesized by blocking the anthraquinone moiety of 1,4-diamino-2,3-diphenoxyanthraquinone(DDAQ) into polyurethane chain using 2,4-tolylene diisocyanate(TDI),poly(propylene glycol) and 2,2-dimethylol propionic acid.The chain structure of DDAQ-TDI-PU was confirmed by means of Fourier transform infrared spectroscopy and UV-vis analysis.Comparing to the UV-vis spectrum of DDAQ,DDAQ-TDI-PU showed a hypsochromic shift from the absorption maxima of 518,558,609 nm to 510,548,586 nm,respectively.It was found that the fluorescence intensity of DDAQ-TDI-PU emulsion was enhanced greatly comparing with that of DDAQ.The fluorescence of DDAQ-TDI-PU was very stable not only for the long term storage but also for the fluorescence quencher.展开更多
A new substrate,aligned Ag nanowires decorated with silver nanoparticle composite structure(AgNWs@AgNPs),was fabricated to investigate metalenhanced fluorescence(MEF) and its mechanism.The new composite structure was ...A new substrate,aligned Ag nanowires decorated with silver nanoparticle composite structure(AgNWs@AgNPs),was fabricated to investigate metalenhanced fluorescence(MEF) and its mechanism.The new composite structure was fabricated via a three-phase interface assembly method followed by SnCl2 sensitization and AgNO3 reduction process.The size and distribution of the nanoparticles on silver nanowires increased with the sensitization and reduction cycles.The formation of AgNPs on the surfaces of AgNWs was confirmed by multiple characterization methods including scanning electron microscopy(SEM),transmission electron microscope(TEM),atomic force microscopy(AFM) and X-ray diffraction(XRD).The results show that the fluorescence intensity of the poly(3-hexylthiophene)(P3HT) on the composite structure was greatly enhanced compared with that on bare glass substrate,and the intensity increased with the increase in particle sizes and density.The mechanism was basedo n the increase in excitation rate and the radiation decay rate.The new type of substrate could serve as a good and efficient MEF substrate for high-performance fluorescence-based devices.展开更多
A new water-stable europium MOF,(Me_(2)NH_(2))[Eu(abtc)(phen)]·2H_(2)O (1),has been synthesized from Eu(NO_(3))_(3)·6H_(2)O with 1,10-phenanthroline (phen) and 3,3′,5,5′-azobenzenetetracarboxylic acid (H_4...A new water-stable europium MOF,(Me_(2)NH_(2))[Eu(abtc)(phen)]·2H_(2)O (1),has been synthesized from Eu(NO_(3))_(3)·6H_(2)O with 1,10-phenanthroline (phen) and 3,3′,5,5′-azobenzenetetracarboxylic acid (H_4abtc) ligands under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction analysis,IR,TGA and PXRD.It crystallizes in monoclinic system,C2/c space group,with a=16.278(3),b=14.261(3),c=27.936(5)?,b=103.464(3)°,V=6307(2)A^(3),Z=8,C_(30)H_(26)Eu N_5O_(10),M_(r)=768.5,D_(c)=1.543 g/cm^(3),F(000)=2912,m(Mo Ka)=2.044 mm^(-1),R=0.0315 and w R=0.0663.In the structure of 1,the Eu O_7N_(2) polyhedra are assembled into a 2D layer with rhombic windows and these layers are further condensed to form a 3D framework.It can be used as selective and sensitive fluorescence sensors capable of detecting diethyl ether vapor.展开更多
Fluorescence enhancement of red and blue concurrently emitting Ba3MgSi2O8:Eu2+,Mn2+ phosphors for plant cultivation has been investigated by Dy3+ addition.The Ba3MgSi2O8:Eu2+,Mn2+,Dy3+(BMS-EMD) phosphors have two-colo...Fluorescence enhancement of red and blue concurrently emitting Ba3MgSi2O8:Eu2+,Mn2+ phosphors for plant cultivation has been investigated by Dy3+ addition.The Ba3MgSi2O8:Eu2+,Mn2+,Dy3+(BMS-EMD) phosphors have two-color emissions at the wavelength peak values of 437 nm and 620 nm at the excitation of 350 nm.The two emission bands are coincident with the absorption spectrum for photosynthesis of plants.An obvious enhancement effect has been observed upon addition of Dy3+ with amount of 0.03 mol%,in which the intensities of both blue and red bands reach a maximum.The origin of red and blue emission bands is analysed.The photochromic parameters of the samples at the nearly UV excitation are tested.This fluoresence enhancement is of great significance for special solid state lighting equipment used in plant cultivation.展开更多
A novel β-diketone, 1-(3,4,5-trisbenzyloxy)benzoyl-5-benzoyl acetylacetone (TBAA), and its corresponding binary Tb(Ⅲ) complex Tb(TBAA)3·2H2O and ternary complex Tb(TBAA)3Phen with 1,10-phenanthroline ...A novel β-diketone, 1-(3,4,5-trisbenzyloxy)benzoyl-5-benzoyl acetylacetone (TBAA), and its corresponding binary Tb(Ⅲ) complex Tb(TBAA)3·2H2O and ternary complex Tb(TBAA)3Phen with 1,10-phenanthroline (Phen) were prepared. The ligand was characterized based on elemental analysis, FT-IR, and 1H NMR. The complexes were characterized with elemental analysis, FT-IR and thermogravimetry and derivative thermogravimetry (TG-DTG). Photoluminescence measurements indicated that the energy absorbed by the organic ligand was efficiently transferred to the central Tb3+ ions, and the complex showed intense and characteristic emissions due to the 5D4→7FJ transitions of the central Tb3+ ions. Both complexes showed longer fluorescence lifetimes. After the introduction of the second ligand Phen group, the relative emission intensities and fluorescence lifetimes of the ternary complex Tb(TBAA)3Phen enhanced more obviously than that of the binary complex Tb(TBAA)3·2H2O. This indicated that the presence of the ligand TBAA and the second ligand Phen could sensitize fluorescence intensities of Tb(Ⅲ) ions, and the introduction of Phen group resulted in the enhancement of the fluorescence properties of the Tb(Ⅲ) ternary rare earth complex.展开更多
The interaction of 7 kinds of cephalosporin-medicine with HSA and BSA was studied and compared using fluorescence enhancement and fluorescence quenching method, then deeply analyzed. The binding characteristics of med...The interaction of 7 kinds of cephalosporin-medicine with HSA and BSA was studied and compared using fluorescence enhancement and fluorescence quenching method, then deeply analyzed. The binding characteristics of medicine with albumin and usual characteristic constants such as dissociation constant, quenching constant, quenching efficiency, energy-transfer efficiency and the distance between donor and accepter were also deeply analyzed.展开更多
The effect of cucurbit[7]uril(CB[7]) on fluorescence properties and biocompatibility of the bis-viologen biphenyl molecule(BPV22+) was investigated by using 1 H NMR spectroscopy,fluorescence emission titration,and in ...The effect of cucurbit[7]uril(CB[7]) on fluorescence properties and biocompatibility of the bis-viologen biphenyl molecule(BPV22+) was investigated by using 1 H NMR spectroscopy,fluorescence emission titration,and in vitro cytotoxicity experiments.CB[7] can be combined with BPV22+ in a stoichiometric ratio of 1:1 and 2:1.After the formation of host-guest complex,the fluorescence emission intensity of BPV22+ increased significantly,and the emission spectrum blue shifted.Meanwhile,the host-guest complexes showed better biocompatibility than BPV22+ in cell cytotoxicity studies.Results of this paper lay a foundation for the development of host-guest type of fluo rescent probes,biological imaging and so forth.展开更多
fluorescence enhancement phenomenon shown by adding scandium ion to thesamarium-thenoyltrifluoroacetone (TTA)-cetyltrimethylammonium bromide(CTMAB)-Triton X-100(TX-100) system was observed and the effect of the condi-...fluorescence enhancement phenomenon shown by adding scandium ion to thesamarium-thenoyltrifluoroacetone (TTA)-cetyltrimethylammonium bromide(CTMAB)-Triton X-100(TX-100) system was observed and the effect of the condi-tions on the system was studied in detail. The excitation and emission wavelengthswere 370 nm, 565 nm, 603 nm and 645 nm, respectively. The optimum conditionsforming Sm-Sc-TTA-CTMAB-TX-100 system were that the concentration of Sc ̄(3+)was equal to 5.0× 10 ̄(-5) mol/L, pH was 7. 7. Under these conditions, the fluores-cence intensity can be increased about 10 times higher than that of the system con-taining no Sc ̄(3+) , and it was a linear function of the concentration of samariumn therange of 1. 0 × 10 ̄(-9)-4. 0 × 10 ̄(-7) mol/L. The detection limit was 6. 0 ×10 ̄(-10) mol/L.This system was used for the spectrofluorimetric determination of samarium withsatisfactory results. The nature of enhanced fluorescence was explained using in-tramolecular and intermolecular energy transfer theory.展开更多
The surface enhanced fluorescence effect of acridine orange fluorophore in the proximity of Au nanoparticles has been investigated experimentally in the system of aqueous solution.Significant enhancement of the fluore...The surface enhanced fluorescence effect of acridine orange fluorophore in the proximity of Au nanoparticles has been investigated experimentally in the system of aqueous solution.Significant enhancement of the fluorescence intensity was observed when the system was excited with 532 nm or 442 nm CW lasers.The influence of the distances between neighboring Au particles as well as that between the fluorophore molecules and the Au surface were explored experimentally.The results demonstrated that a compact distribution of metallic particles was able to produce stronger fluorescence enhancement.Proper separation between the fluorophore molecules and the metal surface was favorable for a better enhancement.展开更多
For the first time, LB films containing Eu(TTA)3Phen are obtained by using composite subphase. Eu(TTA)3Phen itself is dimcult to be transferred onto solid substrate.mixed or alternate LB films are prepared. Hydrogen b...For the first time, LB films containing Eu(TTA)3Phen are obtained by using composite subphase. Eu(TTA)3Phen itself is dimcult to be transferred onto solid substrate.mixed or alternate LB films are prepared. Hydrogen bonds form between Eu(TTA)3Phen and AA or TPP(-COOH). TOPO and SB have a fluorcscence enhanGement effect on Eu(TTA)3Phen. TPP(-COOH) and Fc have a fluorescence quenching effect on it.展开更多
A novel gap-plasmon of Fe3O4@Ag core-shell nanoparticles for surface enhanced fluorescence detection of Rhodamine B(RB) was developed. Fe3O4@Ag core-shell nanostructures with Ag shell and Fe3O4 core were synthetized...A novel gap-plasmon of Fe3O4@Ag core-shell nanoparticles for surface enhanced fluorescence detection of Rhodamine B(RB) was developed. Fe3O4@Ag core-shell nanostructures with Ag shell and Fe3O4 core were synthetized by self-assembled method with the assistance of 3-mercaptopropyl trimethoxy silane(MPTS). To study the RB fluorescence enhanced by gap-plasmon, the fluorescence properties of RB on the substrates with different nanogap densities were systematically investigated, and the results showed that the fluorescence intensity of RB on Fe3O4@Ag core-shell NPs substrate was much stronger than that on bare glass substrate, and the fluorescence intensity was further improved by using multilayer Fe3O4@Ag core-shell NPs substrate which had higher nanogap density. Different from the mechanism that is based on the maximum overlap of the surface plasmon resonance(SPR) band and emission band, the mechanism of the fluorescence enhancement in our work is based on the localized surface plasmon(LSP) and the gap plasmon near-field coupling with the Fe3O4@Ag core-shell NPs. Besides, the detection limit obtained was as low as 1×10^(-7) mol/L, and the Fe3O4@Ag core-shell NPs substrate had high selectivity for RB fluorophores. It was demonstrated that the Fe3O4@Ag core-shell NPs substrate had activity, good stability, and selectivity for fluorescence detection of RB. And the detection of RB by the surface plasmon enhanced fluorescence was more convenient and rapid than the traditional detection methods in previous works.展开更多
基金This work was financially supported by the Science Foundation of Hunan Province, China (No. 01C030)
文摘The fluorescence of terbium (Ⅲ) was enhanced by about three orders of magnitude in the presence of trimellitic acid (benzene-1, 2, 4-tricarboxylic acid (TLA)) in aqueous solution at pH 6. The fluorescence intensity could be greatly increased when the system of Tb^3+-TLA was treated with La^3+ (or Gd^3+) and TritonX- 100. The addition of La^3+ (or Gd^3+) enhanees the fluorescence of the system by about two orders of magnitude due to cofluorescenee, and the TritonX-100 micellar medium plays an important role for stabilization of the system. Both the intermolecular energy transfer mode and intramolecular energy transfer mode are responsible for the mechanism of fluorescence enhancement. In the optimum condi- tions, the fluorescence intensity is a linear function of Tb3~ concentration in the range of 7.8 × 10^-9-3.6 × 10^4 mol/L for the system Tb^3+-La^3+-TLA and 1.0 × 10^-8-4.7 × 10^-5 mol/L for the system Tb^3+-Gd^3+-TLA, and the limits of detection are 4.6 × 10^-10 mol/L and 6.0 × 10^-10 mol/L, respectively.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61078061 and 11104023)the Natural Science Foundation of Liaoning Province,China (Grant No. 20111032)+1 种基金the State Key Development Program for Basic Research of China (Grant No. 2012CB626801)the Fundamental Research Funds for the Central Universities (Grant No. 2011QN152)
文摘The spectral properties of trivalent erbium ions(Er^3+) are systematically studied in a melt-quenched germanate glass(60 GeO2-20PbO-10BaO-10K2O-0.1Ag2O) containing silver(Ag) particles.Thermal treatment of the material leads to the precipitation of Ag particles as observed by transmission electron microscopy and confirmed by absorption spectrum for the obvious surface plasmon resonance peak of Ag particles.The fluorescence from Er^3+ in the 10-min-annealed sample with Ag particles is found to be 4.2 times enhanced compared with the unannealed sample excited by 488-nm Ar+ laser.A comparison is made between a spectral study performed on the unannealed Er^3+-doped sample and the one annealed for 20 min.The data of absorption cross section and Judd-Ofelt intensity parameters show the agreement between the two samples no matter whether there are Ag particles,indicating that the introduction of Ag particles by post-heat treatment has no effect on the crystal field environment of Er^3+ ions.The fluorescence enhancement is attributed to the surface plasmon oscillations of Ag particles in germanate glass.
基金This work is financially supported by the Natural Science Foundation of Hunan Province (No. 01JJY3004) and Technology of China National Packaging Corporation.
文摘Fluorescence and cofluorescence properties of Tb(Ⅲ) solid complexes werestudied using pyromellitic acid (PMA) as ligand and fluorescence inert ions as doping elements. Thecofluorescence enhancement, a result of ligand sensitized fluorescence, was observed in Tb(Ⅲ) solidcomplexes doped with fluorescent inert ions La(Ⅲ), Gd(Ⅲ), Ca(Ⅲ), and Sr(Ⅲ). The effect of thetype and content of doping elements on fluorescence enhancement was studied, and optimum conditionswere determined. The results show that Gd (La, Ca, Sr) has clear cofluorescence effect in solidcomplex Tb-M-PMA system, and in present work, rare earth complex fluorescent powder that emitsbright green fluorescence at ultraviolet excitation was obtained, which had potential application asfluorescent anti-counterfeit ink.
基金Supported by the Ministry of Science and Technology of China under Grant No 2016YFA0202201the National Natural Science Foundation of China under Grant Nos 61290304,11574335 and 61376016+1 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciencesthe 333 Project of Jiangsu province under Grant No BRA2017352
文摘We fabricate nano-structural metal films to improve photoluminescence of perovskite films. When the perovskite film is placed on an ammonia-treated alumina film, stronger photoluminescence is found due to local field en- hancement effects. In addition, the oxide spacer layer between the metal (e.g., AI, Ag and Au) substrate and the perovskite film plays an important role. The simulations and experiments imply that the enhancement is related to surface plasmons of nano-structural metals.
基金supported by the National Natural Science Foundation of China(Grant Nos.61405085 and 61275147)the Research Fund for the Doctoral Program of Liaocheng University,China+1 种基金the Key Project of Science and Technology of Shandong Province of China(Grant No.2010GGX10127)the Shandong Province Natural Science Foundation of China(Grant Nos.ZR2013EML006 and ZR2012AL11)
文摘We present a theoretical study of the influence of a single silver sphere on the fluorescence of radix angelica dahurica, which is a kind of traditional Chinese medicine. The enhancement factors of the excitation and the relaxation processes are deduced. The excitation can be enhanced more than 100 times at 315 nm. The enhancement factor of the emission can reach up to 9 at a center wavelength of 400 nm.
文摘The study of fluorescence enhancement has attracted attention recently. For example, the sensitivity and selectivity of Eu-thenoyltrifluoroacetone (TTA)phenan-throline and Eu-diphacinone-ammonia systems in Triton X-100 micelles are increased by the addition of La;Gd;, Tb;, Lu;or Y;. The mechanism of this fluorescence(?)
基金Supported by the Project of Chongqing Municipal Education Commis-sion(KJ101101)Project of Innovation Team for"Water Quality Vari-ation and Water Environmental Security of Three Gorge Reservoir"of Higher Education in Chongqing City(201024)
文摘[ Objective] The study aims at developing a novel fluorescence enhancement method to determine anionic surfactants. [ Method] Based on Fe3O4 @ PAA-RB fluorescent nanoparticles as fluorescent probes, we have developed a novel fluorescence enhancement method for the determi- nation of an anionic surfactant sodium dodecyl sulfate (SDS) through the gradual optimization of experiment conditions. [ Result] Under the opti- mum conditions, the extent of fluorescence enhancement is directly proportional to SDS concentration varying from 0.5 to 16.0 μmol/L, and the de- tection limit reaches 0.051 μmol/L. The relative standard deviation (RSD) for 4.0 μmol/L SDS is 3.3% ( n =6). The proposed method has been successfully applied to the determination of SDS in environmental water samples, with recovery of 96.3% -105.5%. E Conclusion] The novel fluo- rescence enhancement method is not only simple and rapid, but also has avoided using tedious solvent-extraction and toxic organic solvents.
文摘A new theoretical equation for fluorescence enhancement effect between donor and acceptor has been introduced. By using-it we determined the binding constants and numbers of binding sites of five medicines, including chlorogenic acid, forsythiaside norfloxacin, Ciprofloxacin and fluorenone, to gamma-globulin.
文摘Potential utilization of proteins for early detection and diagnosis of various diseases has drawn considerable interest in the development of protein-based detection techniques. Metal induced fluorescence enhancement offers the possibility of increasing the sensitivity of protein detection in clinical applications. We report the use of tunable plasmonic silver nanostructures for the fluorescence enhancement of a near-infrared (NIR) dye (Alexa Fluor 790). Extensive fluorescence enhan- cement of -2 orders of magnitude is obtained by the nanoscale control of the Ag nanostructure dimensions and interparticle distance. These Ag nanostructures also enhanced fluorescence from a dye with very high quantum yield (7.8 fold for Alexa Fluor 488, quantum efficiency (Qy) = 0.92). A combination of greatly enhanced excitation and an increased radiative decay rate, leading to an associated enhancement of the quantum efficiency leads to the large enhancement. These results show the potential of Ag nanostructures as metal induced fluorescence enhancement (MIFE) substrates for dyes in the NIR "biological window" as well as the visible region. Ag nanostructured arrays fabricated by colloidal lithography thus show great potential for NIR dye-based biosensing applications.
基金Financial supports from the National Natural Science Foundation of China(No.51073144)Natural Science Foundation of Anhui Education Department(No.KJ2011B051)
文摘A novel fluorescent aqueous polyurethane emulsion DDAQ-TDI-PU was synthesized by blocking the anthraquinone moiety of 1,4-diamino-2,3-diphenoxyanthraquinone(DDAQ) into polyurethane chain using 2,4-tolylene diisocyanate(TDI),poly(propylene glycol) and 2,2-dimethylol propionic acid.The chain structure of DDAQ-TDI-PU was confirmed by means of Fourier transform infrared spectroscopy and UV-vis analysis.Comparing to the UV-vis spectrum of DDAQ,DDAQ-TDI-PU showed a hypsochromic shift from the absorption maxima of 518,558,609 nm to 510,548,586 nm,respectively.It was found that the fluorescence intensity of DDAQ-TDI-PU emulsion was enhanced greatly comparing with that of DDAQ.The fluorescence of DDAQ-TDI-PU was very stable not only for the long term storage but also for the fluorescence quencher.
基金financially supported by the National Natural Science Foundation of China (No.51273048)Science and Technology Planning Project of Guangdong Province (No.2017B090915004)the Open Operation of Guangdong Provincial Key Laboratory of Advanced Coatings Research and Development (No.2017B030314105)
文摘A new substrate,aligned Ag nanowires decorated with silver nanoparticle composite structure(AgNWs@AgNPs),was fabricated to investigate metalenhanced fluorescence(MEF) and its mechanism.The new composite structure was fabricated via a three-phase interface assembly method followed by SnCl2 sensitization and AgNO3 reduction process.The size and distribution of the nanoparticles on silver nanowires increased with the sensitization and reduction cycles.The formation of AgNPs on the surfaces of AgNWs was confirmed by multiple characterization methods including scanning electron microscopy(SEM),transmission electron microscope(TEM),atomic force microscopy(AFM) and X-ray diffraction(XRD).The results show that the fluorescence intensity of the poly(3-hexylthiophene)(P3HT) on the composite structure was greatly enhanced compared with that on bare glass substrate,and the intensity increased with the increase in particle sizes and density.The mechanism was basedo n the increase in excitation rate and the radiation decay rate.The new type of substrate could serve as a good and efficient MEF substrate for high-performance fluorescence-based devices.
基金supported by the National Natural Science Foundation of China(21972060)。
文摘A new water-stable europium MOF,(Me_(2)NH_(2))[Eu(abtc)(phen)]·2H_(2)O (1),has been synthesized from Eu(NO_(3))_(3)·6H_(2)O with 1,10-phenanthroline (phen) and 3,3′,5,5′-azobenzenetetracarboxylic acid (H_4abtc) ligands under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction analysis,IR,TGA and PXRD.It crystallizes in monoclinic system,C2/c space group,with a=16.278(3),b=14.261(3),c=27.936(5)?,b=103.464(3)°,V=6307(2)A^(3),Z=8,C_(30)H_(26)Eu N_5O_(10),M_(r)=768.5,D_(c)=1.543 g/cm^(3),F(000)=2912,m(Mo Ka)=2.044 mm^(-1),R=0.0315 and w R=0.0663.In the structure of 1,the Eu O_7N_(2) polyhedra are assembled into a 2D layer with rhombic windows and these layers are further condensed to form a 3D framework.It can be used as selective and sensitive fluorescence sensors capable of detecting diethyl ether vapor.
基金supported by National Natural Science Foundation of China (Grant No 50872091)the Natural Science Foundation of Tianjin,China(06YFJMJC02300,06TXTJJC14602)
文摘Fluorescence enhancement of red and blue concurrently emitting Ba3MgSi2O8:Eu2+,Mn2+ phosphors for plant cultivation has been investigated by Dy3+ addition.The Ba3MgSi2O8:Eu2+,Mn2+,Dy3+(BMS-EMD) phosphors have two-color emissions at the wavelength peak values of 437 nm and 620 nm at the excitation of 350 nm.The two emission bands are coincident with the absorption spectrum for photosynthesis of plants.An obvious enhancement effect has been observed upon addition of Dy3+ with amount of 0.03 mol%,in which the intensities of both blue and red bands reach a maximum.The origin of red and blue emission bands is analysed.The photochromic parameters of the samples at the nearly UV excitation are tested.This fluoresence enhancement is of great significance for special solid state lighting equipment used in plant cultivation.
基金Project supported by Shanxi (20072194 and 20072185) Provincial Youth Technology Research Foundationthe Foundation of Taiyuan Graduate Innovation (100115133 and 100115131)
文摘A novel β-diketone, 1-(3,4,5-trisbenzyloxy)benzoyl-5-benzoyl acetylacetone (TBAA), and its corresponding binary Tb(Ⅲ) complex Tb(TBAA)3·2H2O and ternary complex Tb(TBAA)3Phen with 1,10-phenanthroline (Phen) were prepared. The ligand was characterized based on elemental analysis, FT-IR, and 1H NMR. The complexes were characterized with elemental analysis, FT-IR and thermogravimetry and derivative thermogravimetry (TG-DTG). Photoluminescence measurements indicated that the energy absorbed by the organic ligand was efficiently transferred to the central Tb3+ ions, and the complex showed intense and characteristic emissions due to the 5D4→7FJ transitions of the central Tb3+ ions. Both complexes showed longer fluorescence lifetimes. After the introduction of the second ligand Phen group, the relative emission intensities and fluorescence lifetimes of the ternary complex Tb(TBAA)3Phen enhanced more obviously than that of the binary complex Tb(TBAA)3·2H2O. This indicated that the presence of the ligand TBAA and the second ligand Phen could sensitize fluorescence intensities of Tb(Ⅲ) ions, and the introduction of Phen group resulted in the enhancement of the fluorescence properties of the Tb(Ⅲ) ternary rare earth complex.
基金Project supported by the National Natural Science Foundation of China (No. 30470408) and the Shanxi Provincial Natural Science Foundation
文摘The interaction of 7 kinds of cephalosporin-medicine with HSA and BSA was studied and compared using fluorescence enhancement and fluorescence quenching method, then deeply analyzed. The binding characteristics of medicine with albumin and usual characteristic constants such as dissociation constant, quenching constant, quenching efficiency, energy-transfer efficiency and the distance between donor and accepter were also deeply analyzed.
基金supported by the National Natural Science Foundation of China (No.21374055)the Fundamental Research Funds of Shandong University (No.11190078614092)。
文摘The effect of cucurbit[7]uril(CB[7]) on fluorescence properties and biocompatibility of the bis-viologen biphenyl molecule(BPV22+) was investigated by using 1 H NMR spectroscopy,fluorescence emission titration,and in vitro cytotoxicity experiments.CB[7] can be combined with BPV22+ in a stoichiometric ratio of 1:1 and 2:1.After the formation of host-guest complex,the fluorescence emission intensity of BPV22+ increased significantly,and the emission spectrum blue shifted.Meanwhile,the host-guest complexes showed better biocompatibility than BPV22+ in cell cytotoxicity studies.Results of this paper lay a foundation for the development of host-guest type of fluo rescent probes,biological imaging and so forth.
文摘fluorescence enhancement phenomenon shown by adding scandium ion to thesamarium-thenoyltrifluoroacetone (TTA)-cetyltrimethylammonium bromide(CTMAB)-Triton X-100(TX-100) system was observed and the effect of the condi-tions on the system was studied in detail. The excitation and emission wavelengthswere 370 nm, 565 nm, 603 nm and 645 nm, respectively. The optimum conditionsforming Sm-Sc-TTA-CTMAB-TX-100 system were that the concentration of Sc ̄(3+)was equal to 5.0× 10 ̄(-5) mol/L, pH was 7. 7. Under these conditions, the fluores-cence intensity can be increased about 10 times higher than that of the system con-taining no Sc ̄(3+) , and it was a linear function of the concentration of samariumn therange of 1. 0 × 10 ̄(-9)-4. 0 × 10 ̄(-7) mol/L. The detection limit was 6. 0 ×10 ̄(-10) mol/L.This system was used for the spectrofluorimetric determination of samarium withsatisfactory results. The nature of enhanced fluorescence was explained using in-tramolecular and intermolecular energy transfer theory.
基金supported by the Foundation for the Key Project of the Chinese Ministry of Education (Grant No. 108118)the Fundamental Research Funds for the Central Universities (Grant No. GK200901022)
文摘The surface enhanced fluorescence effect of acridine orange fluorophore in the proximity of Au nanoparticles has been investigated experimentally in the system of aqueous solution.Significant enhancement of the fluorescence intensity was observed when the system was excited with 532 nm or 442 nm CW lasers.The influence of the distances between neighboring Au particles as well as that between the fluorophore molecules and the Au surface were explored experimentally.The results demonstrated that a compact distribution of metallic particles was able to produce stronger fluorescence enhancement.Proper separation between the fluorophore molecules and the metal surface was favorable for a better enhancement.
文摘For the first time, LB films containing Eu(TTA)3Phen are obtained by using composite subphase. Eu(TTA)3Phen itself is dimcult to be transferred onto solid substrate.mixed or alternate LB films are prepared. Hydrogen bonds form between Eu(TTA)3Phen and AA or TPP(-COOH). TOPO and SB have a fluorcscence enhanGement effect on Eu(TTA)3Phen. TPP(-COOH) and Fc have a fluorescence quenching effect on it.
基金Funded by the National Natural Science Foundation of China(NSFC)(Nos.51273048 and 51203025)the Natural Science Foundation of Guangdong Province(No.S2012040007725)
文摘A novel gap-plasmon of Fe3O4@Ag core-shell nanoparticles for surface enhanced fluorescence detection of Rhodamine B(RB) was developed. Fe3O4@Ag core-shell nanostructures with Ag shell and Fe3O4 core were synthetized by self-assembled method with the assistance of 3-mercaptopropyl trimethoxy silane(MPTS). To study the RB fluorescence enhanced by gap-plasmon, the fluorescence properties of RB on the substrates with different nanogap densities were systematically investigated, and the results showed that the fluorescence intensity of RB on Fe3O4@Ag core-shell NPs substrate was much stronger than that on bare glass substrate, and the fluorescence intensity was further improved by using multilayer Fe3O4@Ag core-shell NPs substrate which had higher nanogap density. Different from the mechanism that is based on the maximum overlap of the surface plasmon resonance(SPR) band and emission band, the mechanism of the fluorescence enhancement in our work is based on the localized surface plasmon(LSP) and the gap plasmon near-field coupling with the Fe3O4@Ag core-shell NPs. Besides, the detection limit obtained was as low as 1×10^(-7) mol/L, and the Fe3O4@Ag core-shell NPs substrate had high selectivity for RB fluorophores. It was demonstrated that the Fe3O4@Ag core-shell NPs substrate had activity, good stability, and selectivity for fluorescence detection of RB. And the detection of RB by the surface plasmon enhanced fluorescence was more convenient and rapid than the traditional detection methods in previous works.