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Metal enhanced fluorescence

Bing Yuan, Xiangxu Jiang, Chu Yao, Meimei Bao, Jiaojiao Liu, Yujiang Dou, Yinze Xu, Yao He, Kai Yang, Yuqiang Ma
Metal-enhanced fluorescence shows great potential for improving the sensitivity of fluoroscopy, which has been widely used in protein and nucleic acid detection for biosensor and bioassay applications. In comparison with the traditional glass-supported metal nanoparticles (MNPs), the introduction of a silicon substrate has been shown to provide an increased surface-enhanced Raman scattering (SERS) effect due to the coupling between the MNPs and the semiconducting silicon substrate. In this work, we further study the fluorescence-enhanced effect of the silicon-supported silver-island (Ag@Si) plasmonic chips...
February 22, 2017: Analytica Chimica Acta
Teresa Vargas-Cortez, Jose Ruben Morones-Ramirez, Isaias Balderas-Renteria, Xristo Zarate
Recombinant protein expression in the bacterium Escherichia coli still is the number one choice for large-scale protein production. Nevertheless, many complications can arise using this microorganism, such as low yields, the formation of inclusion bodies, and the requirement for difficult purification steps. Most of these problems can be solved with the use of fusion proteins. Here, the use of the metal-binding protein CusF3H+ is described as a new fusion protein for recombinant protein expression and purification in E...
January 10, 2017: Protein Expression and Purification
Xuechuan Gao, Manjue Zhai, Weihua Guan, Jingjuan Liu, Zhiliang Liu, Alatangaole Damirin
As a result of their extraordinarily large surfaces and well-defined pores, the design of multifunctional metal-organic framework (MOF) is crucial for drug delivery while has been rarely reported. In this paper, a novel drug delivery system (DDS) based on nanoscale metal-organic framework (MOF) was developed for using in cancer diagnosis and therapy. This MOF based tumour targeting DDS was fabricated by a simple post-synthetic surface modification process. Firstly, magnetic mesoporous nanomaterial Fe-MIL-53-NH2 was devoted for encapsulating the drug and served as a magnetic resonance (MR) contrast agent...
January 12, 2017: ACS Applied Materials & Interfaces
Shu Zhu, Xia Lin, Peiyao Ran, Qiao Xia, Chengcheng Yang, Jiao Ma, Yingzi Fu
A novel solid-state electrochemiluminesence (ECL) "on-off" switch system for highly sensitive detection of tryptophan based on the luminescence-functionalized ruthenium metal-organic framework (Ru-MOF) nanoflowers and CdS quantum dots (CdSQDs) was described. Ru-MOF nanoflowers were prepared by a one-step solvothermal method at low temperature and characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectra and fluorescence (FL) spectra...
January 3, 2017: Biosensors & Bioelectronics
Leo Alvarez-Fraga, Esteban Climent-Pascual, Montserrat Xochitl Aguilar-Pujol, Rafael Ramírez-Jiménez, Félix Jiménez-Villacorta, Carlos Prieto, Alicia de Andres
The detection, identification and quantification of different types of molecules and the optical imaging of, for example, cellular processes are important challenges. Here we present how interference enhanced Raman scattering (IERS) in adequately designed heterostructures can provide amplification factors relevant both for detection and imaging. Calculations demonstrate that the key factor is maximizing the absolute value of the refractive indices difference between dielectric and metal layers. Accordingly Si/Al/Al2O3/graphene heterostructures have been fabricated optimizing thickness and roughness and reaching enhancement values up to 700 for 488 nm excitation...
January 5, 2017: ACS Applied Materials & Interfaces
Guojian Chen, Dongzhu Wang, Wei Hong, Lu Sun, Yongxiang Zhu, Xudong Chen
Discontinuous plasmonic-3D photonic crystal hybrid structures are fabricated in order to evaluate the coupling effect of surface plasmon resonance and the photonic stop band. The nanostructures are prepared by silver sputtering deposition on top of hydrophobic 3D photonic crystals. The localized surface plasmon resonance of the nanostructure has a symbiotic relationship with the 3D photonic stop band, leading to highly tunable characteristics. Fluorescence enhancements of conjugated polymer and quantum dot based on these hybrid structures are studied...
January 5, 2017: Small
Guangqian Zhang, Denis Jacquemin, Daniela Buccella
In this joint theoretical and experimental work, we investigate the properties of Mag-fura-2 and seven structurally related fluorescent sensors designed for ratiometric detection of Mg2+ cations. The synthesis of three new compounds is described, and the absorption and emission spectra of all sensors in both their free and metal-bound forms are reported. A Time-Dependent Density Functional Theory approach accounting for hydration effects using a hybrid implicit/explicit model is employed to calculate the absorption and fluorescence emission wavelengths, and to study the origins of the hypsochromic shift caused by metal binding for all the sensors in this family, as well as to investigate the auxochromic effects of various modification of the "fura" core...
January 4, 2017: Journal of Physical Chemistry. B
Yun-Liang Deng, Dang-Dang Xu, Dai-Wen Pang, Hong-Wu Tang
A three-layer core-shell nanostructure consisting of a silver core, a silica spacer, and a fluorescent dye RuBpy-doped outer silica layer was fabricated, and the optimal metal-enhanced fluorescence (MEF) distance was explored through adjusting the thickness of the silica spacer. The results show that the optimal distance is ∼10.4 nm with the maximum fluorescence enhancement factor 2.12. Then a new target-triggered MEF 'turn-on' strategy based on the optimized composite nanoparticles was successfully constructed for quantitative detection of prostate specific antigen (PSA), by using RuBpy as the energy donor and BHQ-2 as the acceptor...
January 3, 2017: Nanotechnology
Minh-Kha Nguyen, Wei-Nien Su, Ching-Hsiang Chen, John Rick, Bing-Joe Hwang
Surface-enhanced Raman scattering (SERS) and fluorescence microscopy are a widely used biological and chemical characterization techniques. However, the peak overlapping in multiplexed experiments and rapid photobleaching of fluorescent organic dyes is still the limitations. When compared to Ag nanocubes (NCs), higher SERS sensitivities can be obtained with thin shelled silica Ag@SiO2 NCs, in contrast metal-enhanced photoluminescence (MEPL) is only found with NCs that have thicker silica shells. A 'dual functionality' represented by the simultaneous strengthening of SERS and MEPL signals can be achieved by mixing Ag@SiO2 NCs, with a silica shell thickness of ~1...
December 18, 2016: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Lixiao Ni, Lili Su, Shiyin Li, Peifang Wang, Dandan Li, Xiang Ye, Yi Li, Yong Li, Yiping Li, Chao Wang
This study examines the uptake of the heavy metal cadmium (Cd) by Microcystis aeruginosa (M. aeruginosa) in the presence of dissolved organic matter (DOM) from different origins. The DOM used in this study were extracted from soil, sediment taken from Meiliang Bay at Taihu Lake and from M. aeruginosa cultured in the laboratory. The three different DOM were characterized using UV-visible absorption spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The excitation-emission matrix (EEM) fluorescence spectroscopy was used to characterize the interactions of DOM with Cd(2+) ...
January 2, 2017: Environmental Toxicology and Chemistry
Hua Lu, Sisi Wang, Yanping Wu, Xuqiong Xiao, Zhifang Li, Mitsuo Kira, Zhen Shen
We describe herein the first facile synthesis of silyl- and disilanyl-BODIPYs through transition-metal-catalyzed dehalosilylation of iodo-BODIPYs using a Pd(P(t-Bu)3)2/Et3N/toluene system. Various mono- and bis-silyl-BODIPYs, mono and bis-disilanyl-BODIPYs and bis-BODIPYs linked by silylene and SiOSi groups have been synthesized by using this straightforward method. Silyl- and disilanyl-substitution significantly modifies the spectroscopic properties of the BODIPY, in which the fluorescence quantum yields of the silyl-BODIPYs are remarkably enhanced, whereas the emission spectra of disilanyl-BODIPYs are red-shifted due to the effective sigma(SiSi)-pi(BODIPY) conjugation...
December 28, 2016: Chemistry, An Asian Journal
Ibrahim Uyanik, Mehmet Oguz, Asif Ali Bhatti, Arzu Uyanik, Mustafa Yilmaz
In this study, we report the synthesis of new Schiff base E-1-(((1-benzylpiperidin-4-yl)imino)methyl)naphthalenee-2-ol (L) and evaluation of its fluorescence response toward Cu(2+) ion. Preliminary, solvent effect, metal selectivity and metal ligand ratio were analyzed through UV-Visible study. Fluorescence response toward Cu(2+) was carried to assess the fluorescent property of synthesized Schiff base. The probe exhibited a higher fluorescence enhancement in the presence of Cu(2+) over other metal ions (Ni(2+), Zn(2+), Hg(2+), Co(2+), Cd(2+), Al(3+), Fe(2+), and Pb(2+))...
December 28, 2016: Journal of Fluorescence
Tasir S Per, Asim Masood, Nafees A Khan
Nitric oxide (NO) is an important gaseous signalling molecule that participates in many developmental and physiological processes, including defense responses against toxic metals in plants. The role of NO in cadmium (Cd)-induced toxic effects on photosynthesis was examined in mustard (Brassica juncea L.) plants. Exposure of plants to 50 μM Cd significantly enhanced oxidative stress (H2O2 content and lipid peroxidation) and impaired plant growth and photosynthesis, chlorophyll fluorescence and reduced chlorophyll content and stomatal conductance...
December 25, 2016: Nitric Oxide: Biology and Chemistry
Kazuyoshi Yano, Akira Iwasaki
A functional modification of the surface of a 96-well microplate coupled with a thin layer deposition technique is demonstrated for enhanced fluorescence-based sandwich immunoassays. The plasma polymerization technique enabling the deposition of organic thin films was employed for the modification of the well surface of a microplate. A silver layer and a plasma-polymerized film were consecutively deposited on the microplate as a metal mirror and the optical interference layer, respectively. When Cy3-labeled antibody was applied to the wells of the resulting multilayered microplate without any immobilization step, greatly enhanced fluorescence was observed compared with that obtained with the unmodified one...
December 25, 2016: Sensors
Hui Wang, Richard Revia, Kui Wang, Rajeev J Kant, Qingxin Mu, Zheng Gai, Kunlun Hong, Miqin Zhang
A boron-doped graphene quantum dot (B-GQD) as a metal-free multimodal contrast agent (CA) for safe magnetic resonance imaging and fluorescence imaging is reported. In vivo T1 -weighted magnetic resonance images show that B-GQDs induce significant contrast enhancement on heart, liver, spleen, and kidney, and sustain for more than 1 h, about 10 times longer than Gd-based CAs currently used in clinic.
December 27, 2016: Advanced Materials
Chang Lu, Yibo Liu, Yibin Ying, Juewen Liu
Interfacing DNA with two-dimensional (2D) materials has been intensely researched for various analytical and biomedical applications. Most of these studies have been performed on graphene oxide (GO) and two metal dichalcogenides, molybdenum disulfide (MoS2) and tungsten disulfide (WS2); all of them can all adsorb single-stranded DNA. However, they use different surface forces for adsorption based on their chemical structures. In this work, fluorescently labeled DNA oligonucleotides were used and their adsorption capacities and kinetics were studied as a function of ionic strength, DNA length, and sequence...
January 5, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Chang Seop Hong, Kwang Soo Lim, So Yeon Jeong, Dong Won Kang, Jeong Hwa Song, Hyuna Jo, Woo Ram Lee, Won Ju Phang, Dohyun Moon
With regard to the fluorescence quenching commonly observed during metal ion detection, "turn-on" chemical sensing has been rarely reported but could be extremely important because it facilitates the selective recognition of target objects of interest against a dark background. We prepared a metal-organic framework (MOF) chemosensor that serves as an efficient platform for the selective detection of Cu2+ and Cd2+ ions over other metal ions. In particular, this framework shows the highest fluorescence enhancement (~60 fold relative to Cd-free MOF) for the hazardous metal ion Cd2+ among luminescent MOFs and displays excellent reusability in repeated cycles...
December 23, 2016: Chemistry: a European Journal
Meng Jin, Zhao-Li Mou, Rui-Ling Zhang, Si-Si Liang, Zhi-Qi Zhang
The development of a simple and accurate quantitative method for the determination of 6-mercaptopurine (6-MP) is of great importance because of its serious side effects. Ratiometric fluorescence (RF) sensors are not subject to interference from environmental factors, and exhibit enhanced precision and accuracy. Therefore, a novel RF sensor for the selective detection of 6-MP was developed based on a dual-emission nanosensor. The nanosensor was fabricated by combining a blue-emission metal-organic framework (MOF) NH2-MIL-53(Al) (λem=425nm) with green-emission 3-mercaptopropionic acid-capped CdTe quantum dots (MPA-CdTe QDs) (λem=528nm) under a single excitation wavelength (335nm)...
December 9, 2016: Biosensors & Bioelectronics
Hussain Fida, Gaoke Zhang, Sheng Guo, Abdul Naeem
The La-Fe montmorillonite (La-Fe MMT) composite was synthesized by a simple precipitation method and was used for the degradation of dyes in both batch and fixed bed experiments. X-ray diffraction (XRD) and high-resolution transmission electron microscope analysis (HRTEM) confirmed the existence of Fe2O3 and La2O3 in the composite. The presence of La enhanced the degradation efficiency of dyes by the composite at neutral pH and results in little iron leaching consequently increasing the lifetime. More than 97% and 96% removal of the MB and RhB (100mg/L each) by the La-Fe MMT Fenton system could be achieved in less than 1h...
March 15, 2017: Journal of Colloid and Interface Science
Soojeong Cho, Wooram Park, Dong-Hyun Kim
Bioinspired melanin nanoparticle (Mel NP) synthesized with dopamine has been of great interest in various biomedical applications. However, the utilization of fascinating characters of Mel NP such as innate MR contrast effects, high affinity to metal ions, strong light absorption requires special design with strategic synthetic method for its own purpose. Here, we have introduced paramagnetic Gd(3+) metal ions and silica nanocoating on Mel NP for the dual-modal MRI/fluorescent contrast-enhanced imaging and therapeutics...
December 19, 2016: ACS Applied Materials & Interfaces
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