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Metal enhanced fluorescence

Thangaraj Anand, S K Ashok Kumar, Suban K Sahoo
In this communication, we have developed an optical chemosensor 2-amino N-(6-bromo-1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)benzamide (NAPH) for selective detection of Al3+ by reacting 4-bromo-1,8-naphthalic anhydride with 2-aminobenzohydrazide. In (DMSO:H2 O, 1:1, v/v) medium, the selective and specific nature of NAPH towards Al3+ was observed by the quenching along with a blue-shift in the absorption of NAPH at 465 nm that resulted in the distinct colour change from light brown to colourless. The selective complexation that occurred between NAPH and Al3+ was investigated by 1 H NMR and DFT methods...
June 11, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Qiuju Yin, Yujie Chen, Meng Zhou, Xiangsheng Jiang, Junjun Wu, Yang Sun
In order to improve the metabolism of pirfenidone (5-methyl-1-phenylpyridin-2-one, PFD), the methyl-deuterated version of pirfenidone via the substitution of hydrogen (H) at C-5 by its isotope deuterium (D, 5D-PFD) was synthesized and its photophysical properties were investigated. The negative solvatochrom was observed in absorption and fluorescence spectra with increasing solvent polarity, which implied that intermolecular charge transfer (ICT) involved n → π* transition for both of PFD and 5D-PFD...
June 7, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Yusra Rahman, Shumaila Afrin, Mohammad Tabish
Studying the interaction of therapeutic molecules with serum albumin is important to understand their biopharmaceutics, pharmacokinetics and toxicity as well as their relation with the structure and function of protein. The biomolecular interaction of an anti-spasmodic drug, pirenzepine with bovine serum albumin (BSA) was investigated using multi-spectroscopic, calorimetric and docking studies. Fluorescence quenching of BSA on interaction with pirenzepine revealed the static mode of quenching. Pirenzepine exhibited a moderate binding to serum albumin with the binding constant value in the order of 104  M-1 ...
June 13, 2018: Archives of Biochemistry and Biophysics
Giulia Zampini, Luigi Tarpani, Giuseppina Massaro, Marta Gambucci, Eugenio Peli, Loredana Latterini
The use of plasmonic nanomaterials is a challenging strategy to control radiation and radiation-induced processes at a nanometric scale. The localized surface plasmons of metal nanoparticles have been shown to affect the efficiency of a variety of radiative and non-radiative processes occurring in organic molecules. In this contribution, we present an overview of the results obtained through an original approach based on the hierarchical assembly of plasmonic gold colloids on silica templates, covalently doped with organic dyes...
June 15, 2018: Photochemical & Photobiological Sciences
Gurpreet Kaur, Preeti Garg, Baljinder Kaur, Ganga Ram Chaudhary, Sandeep Kumar, Neeraj Dilbaghi, P A Hassan, Santosh L Gawali
Bovine serum albumin (BSA) is one of the most copious and significant blood proteins with dynamic structure. The understanding of the structural functionality of BSA and its interaction with metal ions is desired for various biological functions. Herein, three different metallosurfactants containing different transition metals and the same hydrophobic tail were engaged to investigate the structural transition of BSA. The metallosurfactants have been prepared by a combination of metal ions (M = Fe, Co and Ni) with cetylpyridinium chloride surfactant via the ligand insertion method and were characterized by elemental, FTIR, 1H-NMR, and thermogravimetric analysis (TGA)...
June 15, 2018: Soft Matter
Benhua Wang, Jinsong Han, N Maximilian Bojanowski, Markus Bender, Chao Ma, Kai Seehafer, Andreas Herrmann, Uwe H F Bunz
Wet-chemical discrimination of amino acids is still a challenge due to their structural similarity. Here, an optimized self-assembled eight-member sensor array is reported. The optimized sensor array stems from the combination of elements of different tongues, containing poly(para-phenyleneethynylene)s (PPE) and a supercharged green fluorescent protein (GFP) variant. The responsivity of the sensor dyes (PPEs and GFP) is enhanced in elements that contain adjuvants, such as metal salts but also cucurbit[7]uril (CB[7]) and acridine orange; a suitable and robust eight element array discriminates all of the 20 natural amino acids in water at 25mM concentration with 100% accuracy...
June 13, 2018: ACS Sensors
Sharon Xiaodai Lim, Gavin Kok Wai Koon, Zheng Zhang, Antonio H Castro Neto, Eng Soon Tok, Chorng-Haur Sow
We report a functional hybrid made of silver nanoparticles (AgNPs) embedded in an amorphous aluminium oxide (alumina) film. This laser-initiated process allows formation of AgNPs and amorphous alumina in localized regions defined by the scanning laser beam. Due to metal enhanced fluorescence, this hybrid exhibits strong blue fluorescence emission under ultraviolet excitation. Upon irradiating with electrons at dosages of 1 to 20 mC cm-2, AgNPs become more metallic while the Al film is further oxidised. As a result, the fluorescing property is intensified...
June 12, 2018: Nanoscale
Cheng-Zhe Sun, Li-Yi Zhang, Jin-Yun Wang, Zhong-Ning Chen, Feng-Rong Dai
A new sulfonylcalix[4]arene-based dinuclear terbium molecular container (1) was conveniently synthesized and utilized as a fluorescence probe for the detection of a well-known biomarker 1-hydroxypyrene (1-OHP), which is used for the evaluation of polycyclic aromatic hydrocarbons (PAHs). The sulfonylcalix[4]arene ligand could not only serve as an efficient antenna ligand to promote the ligand-to-metal energy transfer but also provide a suitable cavity to accommodate 1-OHP. Promising fluorescence quenching effects were well established during the titration of the compound 1 with 1-OHP, and these effects were due to the enhancement in the host-guest intermolecular charge transfer and the decrease in the ligand-to-metal energy transfer after the formation of the stable host-guest complex...
June 12, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Zsolt Fejes, Zsolt Czimmerer, Tibor Szük, Szilárd Póliska, Attila Horváth, Enikő Balogh, Viktória Jeney, Judit Váradi, Ferenc Fenyvesi, György Balla, István Édes, József Balla, János Kappelmayer, Béla Nagy
We previously found higher level of endothelial cell (EC) activation in patients who suffered from in-stent restenosis after bare-metal stenting compared to subjects who underwent drug-eluting stenting (DES) showing no complications. Here we investigated the potential transcriptional and post-transcriptional regulatory mechanisms by which everolimus attenuated EC activation after DES. We studied the effect of everolimus on E-selectin (SELE) and VCAM1 mRNA levels when human coronary artery (HCAECs) and human umbilical vein ECs were challenged with recombinant TNF-α (100 ng/mL) for 1-24 hours in the presence or absence of everolimus using 0...
2018: PloS One
Tae-Kyoung Kim, Taeyeon Kim, Areum Jo, Suhyun Park, Kyungho Choi, Kyung-Duk Zoh
In this study, we developed a UV-LED/H2 O2 /Cu2+ system to remove cyanide, which is typically present in metal electroplating wastewater. The results showed the synergistic effects of UV-LED, H2 O2 , and Cu2+ ions on cyanide removal in comparison with UV-LED photolysis, H2 O2 oxidation, UV-LED/H2 O2 , and H2 O2 /Cu2+ systems. Cyanide was removed completely in 30 min in the UV-LED/H2 O2 /Cu2+ system, and its loss followed pseudo-first order kinetics. Statistically, both H2 O2 and Cu2+ ions showed positive effects on cyanide removal, but Cu2+ ions exhibited a greater effect...
June 1, 2018: Chemosphere
Zhengye Gu, Heyong Cheng, Xi Shen, Tian He, Kezhi Jiang, Huayu Qiu, Qian Zhang, Shouchun Yin
A BODIPY-based colorimetric and fluorescent chemosensor 1 anchored with dipyridylamino (DPA) receptor has been designed, synthesized and characterized. It exhibited a simultaneous sensitive recognition for Cu2+ , Hg2+ and Pb2+ ions. With the addition of these three kinds of metal ions into 1 in CH3 CN, its initial absorption maximum displayed obvious blue shifts, and the color changes of the solution could be clearly observed by naked eyes. Besides, the fluorescence intensity was significantly enhanced accompanied with the appearance of new emission peaks at 587 nm for Pb2+ and Hg2+ ions and 545 nm for Cu2+ ions...
May 30, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Ji Hu, Zhechao Zhang, Cai Zhang, Shuxia Liu, Haifeng Zhang, Dong Li, Jun Zhao, Zhengbing Han, Xiaoya Liu, Jianming Pan, Wei Huang, Minhui Zheng
The rapid development and application of nanotechnology have led to increasing concern about the environmental implications of released nanomaterials and potential risks to public health and aquatic ecosystems. Information on the joint effect of nanomaterials and co-existing contaminants such as heavy metals is still inadequate. Our work investigated the effect of Al2 O3 nanoparticles (NPs; nano-Al2 O3 ) on the toxic effect of Pb in the unicellular marine phytoplankton Isochrysis galbana. Results showed that a dose-response effect of nano-Al2 O3 was found...
June 4, 2018: Ecotoxicology and Environmental Safety
Yi Wen, Volker M Vogt, Gerald W Feigenson
Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2 or PIP2), is a key component of the inner leaflet of the plasma membrane in eukaryotic cells. In model membranes, PIP2 has been reported to form clusters, but whether these locally different conditions could give rise to distinct pools of unclustered and clustered PIP2 is unclear. By use of both fluorescence self-quenching and Förster resonance energy transfer assays, we have discovered that PIP2 self-associates at remarkably low concentrations starting below 0...
June 5, 2018: Biophysical Journal
Antonio Meola, Jianghong Rao, Navjot Chaudhary, Mayur Sharma, Steven D Chang
Background: Demarcation of malignant brain tumor boundaries is critical to achieve complete resection and to improve patient survival. Contrast-enhanced brain magnetic resonance imaging (MRI) is the gold standard for diagnosis and pre-surgical planning, despite limitations of gadolinium (Gd)-based contrast agents to depict tumor margins. Recently, solid metal-based nanoparticles (NPs) have shown potential as diagnostic probes for brain tumors. Gold nanoparticles (GNPs) emerged among those, because of their unique physical and chemical properties and biocompatibility...
2018: Frontiers in Neurology
Olga D Bekasova, Vita A Stein-Margolina, Boris I Kurganov
Bioconjugates prepared from photoactive molecules and metal nanoparticles are suitable for development of new optoelectronic devices and for theranostic applications in medicine. We produced a bioconjugate of R-phycoerythrin (R-PE), a photosynthetic pigment of red algae, with Ag0 nanoparticles (Ag0 NPs) synthesized in its tunnel cavities by mixing aqueous solutions of AgNO3 and R-PE without exogenous reductant. In freshly prepared bioconjugate (Ag0R-PE), the diameter of Ag0 NPs measured in electron microscopic images was 6...
June 3, 2018: Current Pharmaceutical Biotechnology
Tasuku Hirayama, Satoki Kadota, Masato Niwa, Hideko Nagasawa
Mitochondria are iron-rich organelles that are involved in the process of energy production through the electron-transporting system and heme synthesis. We developed a new mitochondria-targeted fluorescent probe, MtFluNox/Ac-MtFluNox, for Fe(ii) based on N-oxide chemistry, which we recently established as a Fe(ii)-selective fluorogenic switch. The deacetylated form MtFluNox showed a turn-on response towards Fe(ii) with high metal selectivity in cuvette experiments, and an imaging study using its cell-compatible analogue Ac-MtFluNox demonstrated mitochondria-specific fluorescence enhancement in response to Fe(ii) in living cells...
June 4, 2018: Metallomics: Integrated Biometal Science
Niranjan Meher, Swagatika Panda, Sachin Kumar, Parameswar Krishnan Iyer
Restriction of intramolecular motion (RIM) of rigid aromatic cores is the most universal mechanism so far that can successfully explain almost all AIE/AIEEgenic systems. By designing two novel naphthalimide derivatives ( NIB and NIBD ), we experimentally demonstrated the effect of a single formyl group that can efficiently transform an aggregation caused quenching (ACQ) system ( NIB ) into an AIEEgenic system ( NIBD ) by strengthening the RIM process. Besides, the newly designed naphthalimide AIEEgen ( NIBD ) accomplished ultrasensitive detection of hydrazine at the parts per trillion level (LOD/81 ppt) in aqueous media with high selectivity and enormous improvement over the existing state of the art...
April 28, 2018: Chemical Science
Naruphorn Dararatana, Farzad Seidi, Daniel Crespy
In 2015, the global cost of corrosion in the world was estimated to be around 2.5 trillion dollars and is continuously increasing. The active protection by corrosion inhibitors is a well-known technique for protecting metal against corrosion. However, one major disadvantage is that corrosion inhibitors can be leached in the environment, even when corrosion does not occur. We design and synthesize smart polymer/corrosion inhibitor conjugates as new generation of materials for corrosion protection. These materials release inhibitors upon acidification, which may occur either by acidic rain or as consequence of the metal corrosion process itself...
May 29, 2018: ACS Applied Materials & Interfaces
Bagher Eftekhari-Sis, Khadijeh Samadneshan, Saleh Vahdati-Khajeh
A novel nanosensor based on CdSe quantum dots (QDs) capped with 8-hydroxyqunoline (HQ) was developed for Al3+ ions determination in aqueous solutions. The method is based on the fluorescence enhancement of the HQ functionalized QDs in the presence of Al3+ ions, due to the strong interaction between Al3+ and HQ. Prepared nanosensor exhibited an acceptable selectivity and sensitivity for Al3+ ions in the presence of other metal ions. Plot of Log(I/I0 ) against Log[Al3+ ] shows a good linearity in the range of 0...
May 28, 2018: Journal of Fluorescence
Yuxi Liu, Gang Chen, Chong Tian, Rajender Gupta, Xiaogang Wang, Hongbo Zeng
Mercury is an extremely toxic element that is primarily released by anthropogenic activities and natural sources. Controlling Hg emissions, especially from coal combustion flue gas, is of practical importance in protecting the environment and preventing human health risks. In the present work, three metal oxides (MnO2 , CuO, and ZnO) were loaded on graphene oxide (GO) sorbents (designated as MnO2 -GO, CuO-GO, and ZnO-GO). All three adsorbents were successfully synthesized and were well characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS)...
May 28, 2018: Environmental Technology
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