Monodisperse Ag nanoparticles with diameters of about 3.4 nm were synthesized by a facile ultrasonic synthetic route at room temperature with the reduction of borane-tert-butylamine in the presence of oleylamine (OAm...Monodisperse Ag nanoparticles with diameters of about 3.4 nm were synthesized by a facile ultrasonic synthetic route at room temperature with the reduction of borane-tert-butylamine in the presence of oleylamine (OAm) and oleic acid (OA). The reaction parameters of time, the molar ratios of OAm to OA were studied, and it was found that these parameters played important roles in the morphology and size of the products. Meanwhile, surface enhanced Raman spectrum (SERS) property suggested the Ag nanoparticles exhibited high SERS effect on the model molecule Rhodamine 6G. And also, two-photon fluorescence images showed that the silver nanoparticles had high performances in fluorescence enhancement.展开更多
A series of fluorescent chemosensors 1-3 were synthesized to detect transition metal ions. At the room temperature, fluorescence intensities of these chemosensors in acetonitrile without transition metal ions were fou...A series of fluorescent chemosensors 1-3 were synthesized to detect transition metal ions. At the room temperature, fluorescence intensities of these chemosensors in acetonitrile without transition metal ions were found to be very weak, due to the process of the efficient intramolecular photoinduced electron transfer (PET). However, after addition of the transition metal ions, the chemoscnsor 1-3 exhibits obvious fluorescence enhancement. Moreover, the intensity of the fluorescence emission of chemosensors increases significantly in the presence of Zn^2+ and Cd^2+. The fluorescent chemosensors with different polyamine as receptors show diverse affinity abilities to the transition metal ions and signal the receptor-metal ion interaction by the intensity change of fluorescence emission.展开更多
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
The regulator of expression of virion(Rev)protein binds specifically to the Rev-responsive element(RRE)RNA in order to regulate the expression of the human immunodeficiency virus(HIV)-1 genes.Fluorescence indicator di...The regulator of expression of virion(Rev)protein binds specifically to the Rev-responsive element(RRE)RNA in order to regulate the expression of the human immunodeficiency virus(HIV)-1 genes.Fluorescence indicator displacement assays have been used to identify ligands that can inhibit the ReveRRE interaction;however,the small fluorescence indicators cannot fully replace the Rev peptide or protein.As a result,a single rhodamine B labeled Rev(RB-Rev)model peptide was utilized in this study to develop a direct and efficient ReveRRE inhibitor screening model.Due to photon-induced electron transfer quenching of the tryptophan residue on the RB fluorophore,the fluorescence of RB in Rev was weakened and could be dramatically reactivated by interaction with RRE RNA in ammonium acetate buffer(approximately six times).The interaction could reduce the electron transfer between tryptophan and RB,and RRE could also increase RB fluorescence.The inhibitor screening model was evaluated using three known positive ReveRRE inhibitors,namely,proflavin,6-chloro-9-[3-(2-chloroethylamino)propylamino]-2-methoxyacridine(ICR 191),and neomycin,as well as a negative drug,arginine.With the addition of the positive drugs,the fluorescence of the ReveRRE decreased,indicating the displacement of RB-Rev.This was confirmed using atomic force microscopy(AFM)and the fluorescence was essentially unaffected by the addition of arginine.The results demonstrated that RB-Rev can be used as a fluorescent probe for recognizing small ligands that target RRE RNA.The ReveRRE inhibitor screening model offers a novel approach to evaluating and identifying long-acting Rev inhibitors.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
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
Enhancement of uorescent radiation is of great importance for applications including biological imaging,high-sensitivity detectors,and integrated light sources.Strong electromagnetic elds can be created around metalli...Enhancement of uorescent radiation is of great importance for applications including biological imaging,high-sensitivity detectors,and integrated light sources.Strong electromagnetic elds can be created around metallic nanoparticles or in gap of nanostructures,where the local state density of radiating mode is then dramatically enhanced.While enhanced uorescent emission has been demonstrated in many metallic nanoparticles and nanoparticle pairs,simultaneous mediation of absorption and emission processes of uorescent emitters remains challenging in metallic nanostructures.Here,we investigate uorescent emission mediated by metal-dielectric-metal fishnet metasurface,in which localized surface plasmon(LSP)and magnetic plasmon polaritons(MPPs)modes are coupled with absorption and emission processes,respectively.For absorption process,coupling of the LSP mode enables spatially-selective excitation of the uorescent emitters by rotating the polarization of the pump laser beam.In addition,the polarization-dependent MPP mode enables manipulation of both polarization and wavelength of the uorescent emission by introducing a rectangular fishnet structure.All the experimental observations are further corroborated by nite-difference time-domain simulations.The structure reported here has great potential for application to color light-emitting devices and nanoscale integrated light sources.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
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
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 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
Degradation reaction of doxycycline or methacycline was carried out in KOH solution and intense fluorescence was obtained.A degradation mechanism of doxycycline or methacycline was suggested.
The ability of nanoscaled ZnO films to enhance fluorescence was studied. We found that the fluorescence intensities of Cy5, rhodamine 6G, and fiuorescein can be enhanced about 10-fold on nanoscaled ZnO films as compar...The ability of nanoscaled ZnO films to enhance fluorescence was studied. We found that the fluorescence intensities of Cy5, rhodamine 6G, and fiuorescein can be enhanced about 10-fold on nanoscaled ZnO films as compared to that on glass substrates. The lifetimes of all samples were measured, and no obvious change in lifetime was observed for dyes on different substrates. The mechanism for the nanoscaled ZnO film enhanced fluorescence appears to be different from that for the metal-fluorophore systems.展开更多
A facile and rapid approach for detecting low concentration of iron ion(Fe3+) with improved sensitivity was developed on the basis of plasmon enhanced fluorescence and subsequently amplified fluorescence quenching.Au1...A facile and rapid approach for detecting low concentration of iron ion(Fe3+) with improved sensitivity was developed on the basis of plasmon enhanced fluorescence and subsequently amplified fluorescence quenching.Au1Ag4@Si O2 nanoparticles were synthesized and dispersed into fluorescein isothiocyanate(FITC) solution. The fluorescence of the FITC solution was improved due to plasmon enhanced fluorescence. However, efficient fluorescence quenching of the FITC/Au1Ag4@Si O2 solution was subsequently achieved when Fe3+, with a concentration ranging from17 n M to 3.4 l M, was added into the FITC/Au1Ag4@Si O2 solution, whereas almost no fluorescence quenching was observed for pure FITC solution under the same condition. FITC/Au1Ag4@Si O2 solution shows a better sensitivity for detecting low concentration of Fe3+compared to pure FITC solution. The quantized limit of detection toward Fe3+was improved from 4.6 l M for pure FITC solution to 20 n M for FITC/Au1Ag4@Si O2 solution.展开更多
The fluorescence enhancement mechanism of Dy3+-Gd3+- SSA-CTMAB system was studied by the resonance light scattering and fluorescence spectrum. In this paper, the influencing factors including the concentration of Gd...The fluorescence enhancement mechanism of Dy3+-Gd3+- SSA-CTMAB system was studied by the resonance light scattering and fluorescence spectrum. In this paper, the influencing factors including the concentration of Gd3+, ligands, pH value as well as surfactants were studied. As a result, the optimal experimental conditions were obtained. The existence of molecule congeries was proved by scattering-light spectrum.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
Ti_(2)C quantum dots(QDs)with rich surface functional groups have been synthesized using a hydrothermal method,and used to detect tetracycline(Tc)based on enhanced fluorescence.The interaction between the surface func...Ti_(2)C quantum dots(QDs)with rich surface functional groups have been synthesized using a hydrothermal method,and used to detect tetracycline(Tc)based on enhanced fluorescence.The interaction between the surface functional groups of Ti_(2)C QDs and Tc enhanced the fluorescence of Tc at 514 nm,which is used to detect Tc quickly and accurately.Under optimal conditions,the fluorescence intensity was linear to the concentration of Tc in the range of 50.0–30.0μM,with a detection limit of 21.6 nM.Furthermore,the Tc-Ti_(2)C QDs detection system was evaluated for detection of Tc in milk and artificial urine.This study demonstrates a new and simple strategy for Tc detection,which is important for food safety and human health.展开更多
[Objective] The research aimed to construct the fusion protein expression vector of α-galactosidase-EGFP (enhanced green fluorescent protein) in cucumber controlled by CaMV35S promoter.[Method] CaMV35S promoter seq...[Objective] The research aimed to construct the fusion protein expression vector of α-galactosidase-EGFP (enhanced green fluorescent protein) in cucumber controlled by CaMV35S promoter.[Method] CaMV35S promoter sequence and the coding region of EGFP were amplified by polymerase chain reactions (PCR) with vector pCambia 1303 as the template.Using reverse transcript PCR technology,with total RNAs of cucumber as template,the coding region of acid α-galactosidase Ⅰ in cucumber was amplified.The above three fragments were inserted into the multiple cloning sites of expression vector pCambia 1381c.The fusion expression vector of α-galactosidase-EGFP located at the C-terminal of the target genes was constructed.[Result] After enzyme digestion and sequencing,the fusion expression of α-galactosidase-EGFP in cucumber was constructed successfully.[Conclusion] The research laid the experimental basis for further study on the subcellular localization of α-galactosidase in cucumber.展开更多
基金V. ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (No.21071136), the National Basic Research Program of China (No.2010CB934700and No.2012CB932001), the Research FUnd for the Doctoral Program of Higher Education of China (No.20103402110033) and Anhui Provincial Education Department (No.KJ2012ZD11).
文摘Monodisperse Ag nanoparticles with diameters of about 3.4 nm were synthesized by a facile ultrasonic synthetic route at room temperature with the reduction of borane-tert-butylamine in the presence of oleylamine (OAm) and oleic acid (OA). The reaction parameters of time, the molar ratios of OAm to OA were studied, and it was found that these parameters played important roles in the morphology and size of the products. Meanwhile, surface enhanced Raman spectrum (SERS) property suggested the Ag nanoparticles exhibited high SERS effect on the model molecule Rhodamine 6G. And also, two-photon fluorescence images showed that the silver nanoparticles had high performances in fluorescence enhancement.
基金supported by the National Natural Science Foundation of China(No.20332020,No.20472079).
文摘A series of fluorescent chemosensors 1-3 were synthesized to detect transition metal ions. At the room temperature, fluorescence intensities of these chemosensors in acetonitrile without transition metal ions were found to be very weak, due to the process of the efficient intramolecular photoinduced electron transfer (PET). However, after addition of the transition metal ions, the chemoscnsor 1-3 exhibits obvious fluorescence enhancement. Moreover, the intensity of the fluorescence emission of chemosensors increases significantly in the presence of Zn^2+ and Cd^2+. The fluorescent chemosensors with different polyamine as receptors show diverse affinity abilities to the transition metal ions and signal the receptor-metal ion interaction by the intensity change of fluorescence emission.
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 Natural Science Foundation of Shaanxi Province of China(Grant No.:202012119)the Start-up Funding of Shaanxi University of Science and Technology(Grant No.:2019BJ-48)the Innovation Capability Support Program of Shaanxi Province of China(Grant No.:2021PT-044).
文摘The regulator of expression of virion(Rev)protein binds specifically to the Rev-responsive element(RRE)RNA in order to regulate the expression of the human immunodeficiency virus(HIV)-1 genes.Fluorescence indicator displacement assays have been used to identify ligands that can inhibit the ReveRRE interaction;however,the small fluorescence indicators cannot fully replace the Rev peptide or protein.As a result,a single rhodamine B labeled Rev(RB-Rev)model peptide was utilized in this study to develop a direct and efficient ReveRRE inhibitor screening model.Due to photon-induced electron transfer quenching of the tryptophan residue on the RB fluorophore,the fluorescence of RB in Rev was weakened and could be dramatically reactivated by interaction with RRE RNA in ammonium acetate buffer(approximately six times).The interaction could reduce the electron transfer between tryptophan and RB,and RRE could also increase RB fluorescence.The inhibitor screening model was evaluated using three known positive ReveRRE inhibitors,namely,proflavin,6-chloro-9-[3-(2-chloroethylamino)propylamino]-2-methoxyacridine(ICR 191),and neomycin,as well as a negative drug,arginine.With the addition of the positive drugs,the fluorescence of the ReveRRE decreased,indicating the displacement of RB-Rev.This was confirmed using atomic force microscopy(AFM)and the fluorescence was essentially unaffected by the addition of arginine.The results demonstrated that RB-Rev can be used as a fluorescent probe for recognizing small ligands that target RRE RNA.The ReveRRE inhibitor screening model offers a novel approach to evaluating and identifying long-acting Rev inhibitors.
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.
基金supported by the National Nature Science Foundation of China(No.11674303 and No.11574293)the USTC Center for Micro and Nanoscale Research and Fabrication
文摘Enhancement of uorescent radiation is of great importance for applications including biological imaging,high-sensitivity detectors,and integrated light sources.Strong electromagnetic elds can be created around metallic nanoparticles or in gap of nanostructures,where the local state density of radiating mode is then dramatically enhanced.While enhanced uorescent emission has been demonstrated in many metallic nanoparticles and nanoparticle pairs,simultaneous mediation of absorption and emission processes of uorescent emitters remains challenging in metallic nanostructures.Here,we investigate uorescent emission mediated by metal-dielectric-metal fishnet metasurface,in which localized surface plasmon(LSP)and magnetic plasmon polaritons(MPPs)modes are coupled with absorption and emission processes,respectively.For absorption process,coupling of the LSP mode enables spatially-selective excitation of the uorescent emitters by rotating the polarization of the pump laser beam.In addition,the polarization-dependent MPP mode enables manipulation of both polarization and wavelength of the uorescent emission by introducing a rectangular fishnet structure.All the experimental observations are further corroborated by nite-difference time-domain simulations.The structure reported here has great potential for application to color light-emitting devices and nanoscale integrated light sources.
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.
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(?)
文摘Degradation reaction of doxycycline or methacycline was carried out in KOH solution and intense fluorescence was obtained.A degradation mechanism of doxycycline or methacycline was suggested.
基金Project supported by the National Institutes of Health of USA (Grant Nos. HG002655,HG005090,and EB006521)the National Natural Science Foundation of China (Grant No. 50872129)
文摘The ability of nanoscaled ZnO films to enhance fluorescence was studied. We found that the fluorescence intensities of Cy5, rhodamine 6G, and fiuorescein can be enhanced about 10-fold on nanoscaled ZnO films as compared to that on glass substrates. The lifetimes of all samples were measured, and no obvious change in lifetime was observed for dyes on different substrates. The mechanism for the nanoscaled ZnO film enhanced fluorescence appears to be different from that for the metal-fluorophore systems.
基金supported by the National Natural Science Foundation of China (51003069)Natural Science Foundation of Jiangsu Higher Education Institutions of China (10KJB430014)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘A facile and rapid approach for detecting low concentration of iron ion(Fe3+) with improved sensitivity was developed on the basis of plasmon enhanced fluorescence and subsequently amplified fluorescence quenching.Au1Ag4@Si O2 nanoparticles were synthesized and dispersed into fluorescein isothiocyanate(FITC) solution. The fluorescence of the FITC solution was improved due to plasmon enhanced fluorescence. However, efficient fluorescence quenching of the FITC/Au1Ag4@Si O2 solution was subsequently achieved when Fe3+, with a concentration ranging from17 n M to 3.4 l M, was added into the FITC/Au1Ag4@Si O2 solution, whereas almost no fluorescence quenching was observed for pure FITC solution under the same condition. FITC/Au1Ag4@Si O2 solution shows a better sensitivity for detecting low concentration of Fe3+compared to pure FITC solution. The quantized limit of detection toward Fe3+was improved from 4.6 l M for pure FITC solution to 20 n M for FITC/Au1Ag4@Si O2 solution.
基金Acknowledgement: The authors are thankful to the Natural Science Foundation of Shandong Province for its financial support (No. J06105) and the Youth Foundation of ghandong Agricultural University.
文摘The fluorescence enhancement mechanism of Dy3+-Gd3+- SSA-CTMAB system was studied by the resonance light scattering and fluorescence spectrum. In this paper, the influencing factors including the concentration of Gd3+, ligands, pH value as well as surfactants were studied. As a result, the optimal experimental conditions were obtained. The existence of molecule congeries was proved by scattering-light spectrum.
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.
基金supported by the National Natural Science Foundation of China(Nos.22175019 and 52002007)the Fundamental Research Funds for the Central Universitiesthe Youth Teacher International Exchange&Growth Program(No.QNXM20220019).
文摘Ti_(2)C quantum dots(QDs)with rich surface functional groups have been synthesized using a hydrothermal method,and used to detect tetracycline(Tc)based on enhanced fluorescence.The interaction between the surface functional groups of Ti_(2)C QDs and Tc enhanced the fluorescence of Tc at 514 nm,which is used to detect Tc quickly and accurately.Under optimal conditions,the fluorescence intensity was linear to the concentration of Tc in the range of 50.0–30.0μM,with a detection limit of 21.6 nM.Furthermore,the Tc-Ti_(2)C QDs detection system was evaluated for detection of Tc in milk and artificial urine.This study demonstrates a new and simple strategy for Tc detection,which is important for food safety and human health.
基金Supported by National Basic Research Program of China( 2009CB119000)National Natural Science Foundation(30871721)~~
文摘[Objective] The research aimed to construct the fusion protein expression vector of α-galactosidase-EGFP (enhanced green fluorescent protein) in cucumber controlled by CaMV35S promoter.[Method] CaMV35S promoter sequence and the coding region of EGFP were amplified by polymerase chain reactions (PCR) with vector pCambia 1303 as the template.Using reverse transcript PCR technology,with total RNAs of cucumber as template,the coding region of acid α-galactosidase Ⅰ in cucumber was amplified.The above three fragments were inserted into the multiple cloning sites of expression vector pCambia 1381c.The fusion expression vector of α-galactosidase-EGFP located at the C-terminal of the target genes was constructed.[Result] After enzyme digestion and sequencing,the fusion expression of α-galactosidase-EGFP in cucumber was constructed successfully.[Conclusion] The research laid the experimental basis for further study on the subcellular localization of α-galactosidase in cucumber.