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Metal enhanced fluorescence

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https://www.readbyqxmd.com/read/28530401/rational-design-of-mof-nanocarrier-based-co-delivery-system-of-doxorubicin-hydrochloride-verapamil-hydrochloride-for-overcoming-multidrug-resistance-with-efficient-targeted-cancer-therapy
#1
Huiyuan Zhang, Wei Jiang, Ruiling Liu, Jing Zhang, Di Zhang, Zhonghao Li, Yuxia Luan
Conventional organic and inorganic drug nanocarriers suffer from serious drawbacks, such as low drug-storage capacity and uncontrolled release. Moreover, multidrug resistance (MDR) has been one of the primary causes leading to chemotherapy failure for cancers. The main reason of MDR is the overexpressed active efflux transporters such as P-glycoprotein. Here, zeolitic imidazolate framework ZIF-8, as one of the biocompatible metal organic frameworks (MOFs), is reported for the first time as the multidrug carrier to realize the efficient co-delivery of verapamil hydrochloride (VER) as the P-glycoprotein inhibitor as well as doxorubicin hydrochloride (DOX) as an anticancer drug to overcome the MDR in addition to realizing the active targeted ability for an efficient anticancer effect...
May 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28522808/plasmonics-enhanced-smartphone-fluorescence-microscopy
#2
Qingshan Wei, Guillermo Acuna, Seungkyeum Kim, Carolin Vietz, Derek Tseng, Jongjae Chae, Daniel Shir, Wei Luo, Philip Tinnefeld, Aydogan Ozcan
Smartphone fluorescence microscopy has various applications in point-of-care (POC) testing and diagnostics, ranging from e.g., quantification of immunoassays, detection of microorganisms, to sensing of viruses. An important need in smartphone-based microscopy and sensing techniques is to improve the detection sensitivity to enable quantification of extremely low concentrations of target molecules. Here, we demonstrate a general strategy to enhance the detection sensitivity of a smartphone-based fluorescence microscope by using surface-enhanced fluorescence (SEF) created by a thin metal-film...
May 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28516765/peptide-microarray-based-metal-enhanced-fluorescence-assay-for-multiple-profiling-matrix-metalloproteinases-activities
#3
Zhen Lei, Hua Zhang, Yaoqi Wang, Xianying Meng, Zhenxin Wang
Matrix metalloproteinases (MMPs) are closely associated with cancer cell invasion and metastasis. Herein, a fluorescence resonance energy transfer (FRET)-peptide microarray-based metal enhanced fluorescence (MEF) assay is proposed for multiple and sensitive profiling MMPs activities on a novel Au/Ag@SiO2 substrate. The Au/Ag@SiO2 substrate is prepared by electroless deposition of silver on gold nanoparticle (GNP) seeds, followed by SiO2 shell coating and surface functionalization. The specific FRET peptides are spotted on the Au/Ag@SiO2 substrate to sensitively detect MMPs (MMP-2, 3, 7, 9, 14) via fluorescence recovery by the MMP cleavage of quenched peptide motifs, and further enhanced by MEF...
May 18, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28509360/supramolecular-assembly-mediated-by-metal-ions-in-aqueous-solution-and-their-analysis-application
#4
Jing Zhang, Qing Tang, Zhongzheng Gao, Sheng Chao Qiu, Ying Huang, Zhu Tao
A water-soluble fluorescent sensor based on the interaction of the twisted cucurbit[14]uril (tQ[14]) and thiazole orange (TO) in aqueous solution has been developed. Formation of the tQ[14]/TO complex gives rise to strong fluorescence in both of neutral and acidic aqueous solutions compared with that of free TO. Further experiments on the interaction of the tQ[14]/TO complex with metal ions revealed that from a series of nineteen selected common metal ions, 1) only Hg2+ ion can lead to the fluorescence enhancement and then quenching of the tQ[14]/TO complex (2:1) in neutral aqueous solution; 2) only Ba2+ can induce fluorescence quenching of the tQ[14]/TO (2:1) complex in aqueous HCl solution (pH 2)...
May 16, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28505405/structural-basis-for-xenosiderophore-utilization-by-the-human-pathogen-staphylococcus-aureus
#5
Nathaniel P Endicott, Eries Lee, Timothy Adam Wencewicz
Staphylococcus aureus produces a cocktail of metallophores (staphylopine, staphyloferrin A, and staphyloferrin B) to scavenge transition metals during infection of a host. In addition, S. aureus displays the extracellular surface lipoproteins FhuD1 and FhuD2 along with the ABC transporter complex FhuCBG to facilitate the use of hydroxamate xenosiderophores such as desferrioxamine B (DFOB) for iron acquisition. DFOB is used as a chelation therapy to treat human iron overload diseases and has been linked to an increased risk of S...
May 15, 2017: ACS Infectious Diseases
https://www.readbyqxmd.com/read/28501902/a-new-4-amino-7-nitro-2-1-3-benzoxadiazole-anbd-based-fluorescent-probe-for-the-detection-of-hg-2
#6
Ke Wang, Xue Mao, Liling Cao, Guoping Lv, Xinfeng Dong, Yan He, Yongju Wei
Based on the photoinduced electron transfer (PET) principle, 4-amino-7-nitro-2,1,3-benzoxadiazole (ANBD) has been used as a fluorophore to develop a new fluorescent probe, 4-(2-N,N-dimethylthioacetamide)amino-7-nitro-2,1,3-benzoxadiazole (2), for the detection of Hg(2+). Upon the addition of Hg(2+), a 46-fold fluorescence enhancement occurs. Moreover the probe 2 exhibits a high selectivity and sensitivity to Hg(2+), even in the presence of other common metal ions. Under optimal reaction conditions, a good linearity can be obtained in the range of 0...
May 13, 2017: Journal of Fluorescence
https://www.readbyqxmd.com/read/28501218/a-modified-fluorescein-derivative-with-improved-water-solubility-for-turn-on-fluorescent-determination-of-hg-2-in-aqueous-and-living-cells
#7
Shanyi Guang, Jiachan Tian, Gang Wei, Zhengquan Yan, Hongfei Pan, Jihong Feng, Hongyao Xu
To improve the water-solubility of heavy-metal sensing materials, a modified fluorescein-based derivative, acryloyl fluorescein hydrazine (ACFH), was designed and developed by incorporating a non-hydrogen-bonding group into the conjugated molecule for weakening intermolecular hydrogen-bonding interactions. In neutral water environments, ACFH presented a fluorescence-enhancement performance at λmax=512nm in the presence of Hg(2+), which could be visualized by naked-eyes. Under the optimized conditions, the linear range of Hg(2+) detection was 1...
August 1, 2017: Talanta
https://www.readbyqxmd.com/read/28501212/a-selective-and-sensitive-fluorescent-probe-for-the-determination-of-hsa-and-trypsin
#8
Shanshan Huang, Fangfang Li, Caiyun Liao, Baozhan Zheng, Juan Du, Dan Xiao
A simple fluorescent probe HBI-GR based on the combination of the fluorophore (p-HBI) in green fluorescent protein (GFP) and Guanine riboside (GR) for HSA was successfully synthesized. HBI-GR showed an obvious fluorescence enhancement toward HSA without interference from other proteins, amino acids, anions and commonly existing metal ions. HBI-GR exhibited high sensitivity towards HSA with a good linear relationship between the fluorescence intensity of HBI-GR and HSA concentration from 0 to 0.06mgmL(-1). The limit of detection, based on a signal-to-noise ratio of 3, was 15...
August 1, 2017: Talanta
https://www.readbyqxmd.com/read/28494305/photovoltage-response-of-xzn-fe2o4-bifeo3-x-mg-mn-or-ni-interfaces-for-highly-selective-cr-3-cd-2-co-2-and-pb-2-ions-detection
#9
Liang Bian, Yu-Jin Li, Jing Li, Jia-Nan Nie, Fa-Qin Dong, Mian-Xin Song, Li-Sheng Wang, Hai-Liang Dong, Hai-Long Li, Xiao-Qin Nie, Xiao-Yan Zhang, Xin-Xi Li, Lei Xie
High-photostability fluorescent (XZn)Fe2O4 (X=Mg, Mn or Ni) embedded in BiFeO3 spinel-perovskite nanocomposites were successfully fabricated via a novel bio-induced phase transfer method using shewanella oneidensis MR-1. These nanocomposites have the near-infrared fluorescence response (XZn or Fe)-O-O-(Bi) interfaces (785/832nm), and the (XZn)Fe2O4/BiFeO3 lattices with high/low potentials (572.15-808.77meV/206.43-548.1meV). Our results suggest that heavy metal ion (Cr(3+), Cd(2+), Co(2+) and Pb(2+)) d↓ orbitals hybridize with the paired-spin X-Zn-Fe d↓-d↓-d↑↓ orbitals to decrease the average polarization angles (-29...
May 1, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28493379/a-highly-selective-fluorescent-chemosensor-for-cu-2-synthesis-and-properties-of-a-rhodamine-b-containing-diarylethene
#10
Dandan Xue, Chunhong Zheng, Shengzu Qu, Guanming Liao, Congbin Fan, Gang Liu, Shouzhi Pu
A diarylethene bearing a triazole-linked rhodamine B unit was synthesized. Its fluorescent emission was significantly enhanced in the presence of protons or Cu(2)(+) due to transformation from the pirocyclic form to open-ring form. The fluorescence was quenched sequentially upon irradiation with 297 nm light based on the intramolecular fluorescence resonance energy transfer mechanism. In an acetonitrile: water binary solvent (1: 1 v/v), the compound showed significant fluorescent enhancement for Cu(2)(+) compared with a wide range of tested metal ions with a fast response and a limit of detection of 2...
June 2017: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/28492624/a-simple-quinolone-schiff-base-containing-chef-based-fluorescence-turn-on-chemosensor-for-distinguishing-zn-2-and-hg-2-with-high-sensitivity-selectivity-and-reversibility
#11
Yuwei Dong, Ruiqing Fan, Wei Chen, Ping Wang, Yulin Yang
A new simple 'dual' chemosensor MQA ((E)-2-methoxy-N-((quinolin-2-yl)methylene)aniline) for distinguishing Zn(2+) and Hg(2+) has been designed, synthesized and characterized. The sensor showed excellent selectivity and sensitivity with a fluorescence enhancement to Zn(2+)/Hg(2+) over other commonly coexisting cations (such as Na(+), Mg(2+), Al(3+), K(+), Mn(2+), Fe(2+), Fe(3+), Co(2+), Ni(2+), Cu(2+), Ga(3+), Cd(2+), In(3+) and Pb(2+)) in DMSO-H2O solution (1/99 v/v), which was reversible with the addition of ethylenediaminetetraacetic acid (EDTA)...
May 11, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28487819/selective-detection-of-mg-2-ions-via-enhanced-fluorescence-emission-using-au-dna-nanocomposites
#12
Tanushree Basu, Khyati Rana, Niranjan Das, Bonamali Pal
The biophysical properties of DNA-modified Au nanoparticles (AuNPs) have attracted a great deal of research interest for various applications in biosensing. AuNPs have strong binding capability to the phosphate and sugar groups in DNA, rendering unique physicochemical properties for detection of metal ions. The formation of Au-DNA nanocomposites is evident from the observed changes in the optical absorption, plasmon band, zeta potential, DLS particle size distribution, as well as TEM and AFM surface morphology analysis...
2017: Beilstein Journal of Nanotechnology
https://www.readbyqxmd.com/read/28485911/photoluminescence-of-functionalized-germanium-nanocrystals-embedded-in-arsenic-sulfide-glass
#13
Tingyi Gu, Jia Gao, Evgeny E Ostroumov, Hyuncheol Jeong, Fan Wu, Romain Fardel, Nan Yao, Rodney D Priestley, Gregory D Scholes, Yueh-Lin Loo, Craig B Arnold
Embedding metallic and semiconductor nanoparticles in a chalcogenide glass matrix effectively modifies the optical properties. Such nanostructured materials could play an important role in optoelectronic devices, catalysis and imaging applications. In this work, we fabricate and characterize germanium nanocrystals (Ge NCs) embedded in arsenic sulfide thin films by pulsed laser ablation in aliphatic amine solutions. Unstable surface termination of aliphatic groups and stable termination by amine on Ge NCs are indicated by Raman and Fourier-transform infrared spectroscopy measurements, respectively...
May 9, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28481503/adhesion-enhancements-and-sers-activity-of-ag-and-ag-sio2-nanoparticle-decorated-ragweed-pollen-micro-particle-sensor
#14
Lucas R Johnstone, Ismael J Gomez, Haisheng Lin, Oluwatimilehin O Fadiran, Vincent W Chen, J Carson Meredith, Joseph W Perry
A simple solution processed layer-by-layer approach was used to immobilize metal nanoparticles (NP) on the surface of ragweed pollen exine to obtain multifunctional particles with significant surface-enhanced Raman scattering (SERS), two-photon excited fluorescence and enhanced adhesion properties. The rugged pollen exine was functionalized with an amine terminated silane and then treated with Ag or Ag@SiO2 NPs that were electrostatically attached to the exterior of the pollen by incubation in a NP solution of the appropriate pH...
May 8, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28475492/a-highly-selective-turn-on-fluorescent-probe-for-al3-in-aqueous-solution-based-on-quinoline-schiff-base
#15
Peng-Cheng Huang, Hao Fang, Jing-Jing Xiong, Fang-Ying Wu
A new Al3+-specific fluorescent probe NQ was designed and synthesized from 2-hydroxy-1-naphthaldehyde and 2-aminoquinoline. Upon addition of Al3+, the fluorescent intensity of NQ has a significant enhancement over other examined metal ions in aqueous solution. The result of Job's plot indicated the formation of 1:1 complex between probe and Al3+, and the possible binding mode of the system between NQ and Al3+ was clarified by IR analysis and 1H NMR titration. Moreover, other metal ions examined had little effect on the detection of Al3+...
May 5, 2017: Methods and Applications in Fluorescence
https://www.readbyqxmd.com/read/28474900/water-soluble-cationic-metalloporphyrins-specific-g-quadruplex-stabilizing-ability-and-reversible-chirality-of-aggregates-induced-by-at-rich-dna
#16
Yan-Fang Huo, Li-Na Zhu, Ke-Ke Liu, Li-Na Zhang, Ran Zhang, De-Ming Kong
Cu-TMPipPrOPP and Zn-TMPipPrOPP, two new cationic metallo derivatives of TMPipPrOPP (5,10,15,20-tetrakis{4-[3-(1-methyl-1-piperidinyl)propoxy]phenyl}porphyrin), a porphyrin with four bulky side chains, were synthesized and characterized. The interactions of the new metalloporphyrins with structurally different DNAs were then compared with those of TMPipPrOPP. The introduction of bulky side chains provides the porphyrin derivatives with excellent binding specificity for G-quadruplex DNA, which is reflected by (1) the significantly different optical responses of TMPipPrOPP toward G-quadruplexes in comparison with single-stranded and duplex DNAs and (2) the ability of the three porphyrin derivatives to effectively stabilize G-quadruplexes, with no or little effect on the stability of duplex DNA...
May 5, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28468496/protein-guided-formation-of-silver-nanoclusters-and-their-assembly-with-graphene-oxide-as-an-improved-bioimaging-agent-with-reduced-toxicity
#17
Niloy Kundu, Devdeep Mukherjee, Tapas Kumar Maiti, Nilmoni Sarkar
As an emerging category of fluorescent metal nanoclusters (NCs), protein-based NCs are considered as one of the promising candidates for the biomedical applications because of their luminescent properties and inherent biocompatibilities. Protein-capped silver NCs impregnated onto graphene oxide (GO) sheets can be internalized into the K562 cell, a human erythroleukemic cell line, and the Ag NCs/GO assembly can act as a synergistic drug carrier for Imatinib, a first-generation tyrosine kinase inhibitor. Further, Ag NCs adsorbed on GO have a great potential to be used as X-ray computer tomography (CT) imaging contrasting agents, and CT images show significant contrast enhancement of bone tissues in mice models...
May 9, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28468368/size-and-distance-dependent-fluorescence-enhancement-of-nanoporous-gold
#18
Chao Chen, Ling Zhang, Min Yang, Chunxian Tao, Zhaoxia Han, Bin Chen, Heping Zeng
Nanoporous gold (NPG) has been reported to provide remarkable fluorescence enhancement of adjacent fluorophores due to the metal-enhanced fluorescence phenomenon (MEF), and the enhancement is related with the characteristic length of nanoporosity. To fully understand the effect of NPG on nearby fluorophores, it is desirable to study systems with well-defined metal-fluorophore distances. In this study we investigated the distance effect by using silica as the spacing layer between fluorophores and NPG. Originating from competition between plasmonic amplifying and metallic quenching, the dye molecule rhodamine 6G was best enhanced by 20-nm SiO<sub>2</sub> coated nanoporous gold with the pore size of 36 nm, while the protein phycoerythrin was best enhanced by 15-nm SiO<sub>2</sub> coated nanoporous gold with the pore size of 42 nm and the quantum dots were best enhanced by 20-nm SiO<sub>2</sub> coated nanoporous gold with the pore size of 42 nm...
May 1, 2017: Optics Express
https://www.readbyqxmd.com/read/28467701/bivalent-aptasensor-based-on-silver-enhanced-fluorescence-polarization-for-rapid-detection-of-lactoferrin-in-milk
#19
Zhu Chen, Hui Li, Wenchao Jia, Xiaohui Liu, Zhoumin Li, Fang Wen, Nan Zheng, Jindou Jiang, Danke Xu
Here we report a novel type of bivalent aptasensor based on silver-enhanced fluorescence polarization (FP) for detection of lactoferrin (Lac) in milk powder with high sensitivity and specificity. The novel two split aptamers were obtained from the aptamer reported in our previous SELEX (systematic evolution of ligands by exponential enrichment) selection, and their minimal structural units were optimized on the basis of their affinity and specificity. Also, dual binding sites of split aptamers were verified...
May 12, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28460166/shielding-against-unfolding-by-embedding-enzymes-in-metal-organic-frameworks-via-a-de-novo-approach
#20
Fu-Siang Liao, Wei-Shang Lo, Yu-Shen Hsu, Chang-Cheng Wu, Shao-Chun Wang, Fa-Kuen Shieh, Joseph V Morabito, Lien-Yang Chou, Kevin C-W Wu, Chia-Kuang Tsung
We show that an enzyme maintains its biological function under a wider range of conditions after being embedded in metal-organic framework (MOF) microcrystals via a de novo approach. This enhanced stability arises from confinement of the enzyme molecules in the mesoporous cavities in the MOFs, which reduces the structural mobility of enzyme molecules. We embedded catalase (CAT) into zeolitic imidazolate frameworks (ZIF-90 and ZIF-8), and then exposed both embedded CAT and free CAT to a denature reagent (i.e...
May 8, 2017: Journal of the American Chemical Society
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