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Metal enhanced fluorescence

Junwei Ye, Raji Feyisa Bogale, Yangwei Shi, Yanzhen Chen, Xigang Liu, Yaoyao Yang, Siqi Zhang, Jianzhang Zhao, Guiling Ning
A stable 3D Tb(III)-based metal-organic framework [Tb(BPDC)2]*(CH3)2NH2 (DUT-101) was synthesized, and it is the first efficient dual-channel luminescence sensor for aqueous UO22+ ion. DUT-101 possesses an anionic three-dimensional framework and protonated dimethylamine molecules embedded within the channels. Intense green emission of DUT-101 could be highly selectively and sensitively quenched by UO22+ ions even in the coexistence of other competing metal ions. The possible sensing mechanism was proposed as well based on both suppression of luminescence resonance energy transfer and enhancement of intermolecular electronic transfer...
April 27, 2017: Chemistry: a European Journal
M N Shinde, R Khurana, N Barooah, A C Bhasikuttan, J Mohanty
The host-guest interactions and the consequent modulation in the prototropic equilibrium of a phenazine dye, neutral red, with p-sulfonatocalix[4]arene (SCX4) and p-sulfonatocalix[6]arene (SCX6) macrocyclic hosts have been investigated. Both the neutral (NR) and cationic (NRH(+)) forms of dyes formed inclusion complexes with SCX6, with a larger binding constant for the latter (K = 8.6 × 10(5) M(-1)versus 4.8 × 10(3) M(-1)) due to the cation receptor behavior of the calixarenes. The distinct differences in the binding constant of NR and NRH(+) provided a finite tuning of pKa between 6...
April 26, 2017: Organic & Biomolecular Chemistry
Fang-Cheng Liang, Chi Ching Kuo, Bo-Yu Chen, Chia-Jung Cho, Chih-Chien Hung, Wen-Chang Chen, Redouane Borsali
Novel red-green-blue (RGB) switchable probes based on fluorescent porous electrospun (ES) nanofibers exhibiting high sensitivity to pH and mercury ions (Hg2+) were prepared with one type of copolymer (poly(methyl methacrylatete-co-1, 8-naphthalimide derivatives-co-rhodamine derivative); poly(MMA-co-BNPTU-co-RhBAM)) by using a single-capillary spinneret. The MMA, BNPTU, and RhBAM moieties were designed to (i) permit formation of porous fibers, (ii) fluoresce for Hg2+ detection, and (iii) fluoresce for pH, respectively...
April 25, 2017: ACS Applied Materials & Interfaces
Paloma Menguer, Thomas Vincent, Anthony J Miller, James K M Brown, Eva Vincze, Søren Borg, Preben Bach Holm, Dale Sanders, Dorina Podar
Zinc (Zn) is essential for all life forms, including humans. It is estimated that around two billion people are deficient in their Zn intake. Human dietary Zn intake relies heavily on plants, which in many developing countries consists mainly of cereals. The inner part of cereal grain, the endosperm, is the part that is eaten after milling but contains only a quarter of the total grain Zn. Here we present results demonstrating that endosperm Zn content can be enhanced through expression of a transporter responsible for vacuolar Zn accumulation in cereals...
April 24, 2017: Plant Biotechnology Journal
Bahram Ghanbari, Morteza Zarepour-Jevinani
The noticeable enhancement in fluorescence emission of O2N2-donor naphthodiaza-crown macrocyclic ligand (L) in the presence of Hg(2+) was observed in which the fluorescence quantum yield of free ligand L as well as L/Hg(2+) complex were found to be as 0.29 and 0.49, respectively. The observed ultra-low limit of detection (LOD) for Hg(2+) by L was determined as low as 1.0 × 10(-11) M in water. A 1:1 stoichiometry was also established for L/Hg(2+) together with a binding constant K BH = 66,543 by employing fluorescence spectrophotometry...
April 20, 2017: Journal of Fluorescence
Xiaofeng Ban, Abhishek S Dhoble, Caiming Li, Yuzhu Zhang, Zhengbiao Gu, Li Cheng, Yan Hong, Zhaofeng Li
Metal ions are essential for the performance of metal-dependent proteins and are known to be important for thermophilic proteins containing a large number of charged residues. The performance of thermophilic proteins may be influenced by metal ions through electrostatic interactions between the metal ions and charged residues. In this study, we investigated the effects of metal ions and glycerol on the activity and stability of the thermophilic 1,4-α-glucan branching enzyme (abbreviated GBE; EC from G...
April 17, 2017: International Journal of Biological Macromolecules
Jiaoliang Wang, Liping Long, Li Xia, Fang Fang
A near-infrared fluorescent probe NIR-Hg ,for detection of Hg2+ ion, has been synthesized directly by condensing Changsha dye with 4-Phenyl-3-thiosemicarbazide and the structure has fully characterized by 1HNMR, 13CNMR, and ESI-MS. The probe has been designed, on the basis of the reaction that Hg2+ ion promotes thiosemicarbazide to oxazole in aqueous media and had been induced to produce turn-on fluorescence via an irreversible spirolactam ring-opening process. The probe NIR-Hg has exhibited fast response (1 min), high sensitivity with 44-fold fluorescence intensity enhancement under 6 equivalent of Hg2+ added, high selectivity over other related metal ions and the low detection limit of 5...
April 18, 2017: Methods and Applications in Fluorescence
Irulappan Manikandan, Chien-Huei Chang, Chia-Ling Chen, Veerasamy Sathish, Wen-Shan Li, Mahalingam Malathi
Novel benzimidazoquinoline derivative (AVT) was synthesized through a substitution reaction and characterized by various spectral techniques. Analyzing the optical properties of AVT under absorption and emission spectral studies in different environments exclusively with respect to solvents and pH, intriguing characteristics viz. aggregation induced emission enhancement (AIEE) in the THF solvent and 'On-Off' pH sensing were found at neutral pH. Sensing nature of AVT with diverse metal ions and bovine serum albumin (BSA) was also studied...
March 25, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Mei Zhang, Baoxiu Liu
Metal tolerance proteins (MTPs) are a gene family of cation efflux transporters that occur widely in plants and might serve an essential role in metal homeostasis and tolerance. Our research describes the identification, characterization, and localization of OsMTP11, a member of the MTP family from rice. OsMTP11 was expressed constitutively and universally in different tissues in rice plant. Heterologous expression in yeast showed that OsMTP11 complemented the hypersensitivity of mutant strains to Mn, and also complemented yeast mutants to other metals, including Co and Ni...
2017: PloS One
Cheng Peng, Chen Xu, Qinglin Liu, Lijuan Sun, Yongming Luo, Jiyan Shi
Agricultural soil is gradually becoming a primary sink for metal-based nanoparticles (MNPs). The uptake and accumulation of MNPs by crops may contaminate food chain and pose unexpected risks for human health. Here, we investigated the fate and transformation of CuO nanoparticles (NPs) in the soil-rice system during the rice lifecycle. The results show that at the maturation stage, 1000 mg/kg CuO NPs significantly decreased redox potential by 202.75 mV but enhanced electrical conductivity by 497.07 mS/cm compared to controls...
April 6, 2017: Environmental Science & Technology
M Lin, Z L Cao, H C Ong
When light emitters are being placed in close proximity to a plasmonic system, not only the emission but also the excitation can be strongly enhanced and both yield the surface plasmon polariton (SPP) mediated fluorescence enhancement. Here, we combine the rate equation model and coupled mode theory to formulate the excitation rate of light emitters located on a periodic metallic array. The rate is expressed in terms of quantities that can be measured by angle- and polarization-resolved reflectivity and photoluminescence spectroscopy...
March 20, 2017: Optics Express
Wei Li, Yumin Hou
In this article, we introduce a new optical energy focusing structure consisting of a circular dielectric Bragg nanocavity and a circular metallic plasmonic lens. Via the hybridization of Bragg cavity modes and surface plasmon modes, optical energy is highly confined in the central region of the Bragg nanocavity under linearly polarized illumination. When either a bowtie nano-antenna (BNA) or a magnetic resonator (MR) is placed on this focusing structure, the energy can be high-efficiently coupled and focused into the BNA or MR...
April 3, 2017: Optics Express
Bin Zhong, Xiangqin Wang, Huilin Mao, Yiqi Wan, Yi Liu, Tao Zhang, Chengyu Hu
Heavy metal exposure impacts basic cellular processes and results in serious toxicological effects. Pb(2+) can activate the response to endoplasmic reticulum (ER) stress by protein denaturation, changing intracellular calcium homeostasis, and inducing cell death. As an ER retention protein, 78-kDa glucose-regulated protein (GRP78) can relieve the Pb(2+)-induced ER stress and enhance cell viability. We previously showed that heavy metal ions such as Pb(2+) etc. are harmful to fish cell lines in a time- and dose-dependent manner...
April 1, 2017: Fish & Shellfish Immunology
Won-Il Lee, Sajal Shrivastava, Le-Thai Duy, Bo Yeong Kim, Young-Min Son, Nae-Eung Lee
The accuracy of a bioassay based on smartphone-integrated fluorescent biosensors has been limited due to the occurrence of false signals from non-specific reactions as well as a high background and low signal-to-noise ratios for complementary metal oxide semiconductor image sensors. To overcome this problem, we demonstrate dual-wavelength fluorescent detection of biomolecules with high accuracy. Fluorescent intensity can be quantified using dual wavelengths simultaneously, where one decreases and the other increases, as the target analytes bind to the split capture and detection aptamer probes...
March 30, 2017: Biosensors & Bioelectronics
Yiru Li, Yang Liu, Haitao Zhou, Wei Chen, Ju Mei, Jianhua Su
Two novel ratiometric fluorometric probes 6a and 6b have been successfully designed and synthesized for the detection of Hg2+ and Ag+, respectively. Each of these probes is comprised of a 9,14-diphenyl-9,14-dihydrodibenzo[a,c]phenazine (DPAC) skeleton, a tetraphenylethylene (TPE) unit, and two thymine/adenine groups. In this proof-of-concept work, the DPAC unit featured with vibration-induced emission (VIE) characteristics serves as a dual-emission chromogen, while the TPE moiety which is noted for its aggregation-induced emission (AIE) properties functions mainly as a signal amplifier...
March 29, 2017: Chemistry: a European Journal
Xixi Cai, Qian Yang, Jiaping Lin, Nanyan Fu, Shaoyun Wang
Marine microorganisms have been proposed as a new kind of protein source. Efforts are needed in order to transform the protein-rich biological wastes left after lipid extraction into value-added bio-products. Thus, the utilization of protein recovered from defatted Schizochytrium sp. by-products presents an opportunity. A specific peptide Tyr-Leu (YL) with calcium-binding capacity was purified from defatted Schizochytrium sp. protein hydrolysates through gel filtration chromatography and RP-HPLC. The calcium-binding activity of YL reached 126...
March 29, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Ting Song, Yuan Cao, Gang Zhao, Lin Pu
Fluorescence responses of two BINOL-based diastereomeric salicylaldimines toward a variety of metal cations have been studied in methanol solution. It is revealed that both compounds show great fluorescence enhancements in the presence of Zn(2+) but not with any other metal ions. Moreover, these two diastereomers exhibit dramatically different responses toward Zn(2+) under the same conditions. That is, one can produce much stronger fluorescence enhancement also at a longer wavelength than the other. This fluorescence recognition of Zn(2+) also shows distinctive color changes under a UV lamp...
March 27, 2017: Inorganic Chemistry
Oluwasesan Adegoke, Masahiro Morita, Tatsuya Kato, Masahito Ito, Tetsuro Suzuki, Enoch Y Park
The current epidemic caused by the Zika virus (ZIKV) and the devastating effects of this virus on fetal development, which result in an increased incidence of congenital microcephaly symptoms, have prompted the World Health Organization (WHO) to declare the ZIKV a public health issue of global concern. Efficient probes that offer high detection sensitivity and specificity are urgently required to aid in the point-of-care treatment of the virus. In this study, we show that localized surface plasmon resonance (LSPR) signals from plasmonic nanoparticles (NPs) can be used to mediate the fluorescence signal from semiconductor quantum dot (Qdot) nanocrystals in a molecular beacon (MB) biosensor probe for ZIKV RNA detection...
March 22, 2017: Biosensors & Bioelectronics
Wenjie Feng, Qing Xia, Haiyan Zhou, Yun Ni, Liulin Wang, Su Jing, Lin Li, Wei Ji
A novel anthrancene-dopamine thioether L compound was designed as fluorescent probe for detecting Hg(2+) in living cells sample. L exhibits a good sensitive and selective recognition towards Hg(2+) ions in the presence of other important relevant metal ions and amino acids in HEPES solution. The addition of Hg(2+) causes a marked enhancement in the fluorescence emission intensity with the detection limit as low as 1.1×10(-6)M, combining with obvious colormetric change from colorless to pale brown. Mechanistic studies show that catechol group and sulfur atom in L all participate in the coordination with Hg(2+), though catechol group contributes mainly to chelation-enhanced fluorescence enhancement and sulfur atom to selectivity...
May 15, 2017: Talanta
Yangyang Zhao, Jing Zhao, Guiye Shan, Dongmei Yan, Yanwei Chen, Yichun Liu
It is important to control drug release and detect the distribution of drug molecules before and after release. In this work, liposome@AgAu nanocomposite is prepared for drug delivery, which not only can control drug release by near infrared laser irradiation but also can monitor drug molecules by surface enhanced Raman scattering (SERS) and fluorescence signal during the release process. The liposome@AgAu core/shell nanocomposite prepared by the galvanic replacement reaction (GRR) shows tunable localized surface plasmon resonance (LSPR) absorption peaks from visible to near-infrared region and good biocompatibility...
March 8, 2017: Colloids and Surfaces. B, Biointerfaces
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