Strategy for Sensor Based on Fluorescence Emission Red Shift of Conjugated Polymers: Applications in pH Response and Enzyme Activity Detection

2012 ◽  
Vol 85 (2) ◽  
pp. 825-830 ◽  
Author(s):  
Yanli Tang ◽  
Yue Liu ◽  
Ali Cao
Keyword(s):  
Enzyme Activity ◽  
Conjugated Polymers ◽  
Fluorescence Emission ◽  
Red Shift ◽  
Activity Detection ◽  
Ph Response

Enzymatic condensation of dopamine and acetaldehyde: a salsolinol synthase from rat brain

Biologia ◽  
2011 ◽  
Vol 66 (6) ◽  
Author(s):  
Xuechai Chen ◽  
Abida Arshad ◽  
Hong Qing ◽  
Rui Wang ◽  
Jianqing Lu ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Substantia Nigra ◽  
Human Subjects ◽  
Enzymatic Reaction ◽  
Brain Regions ◽  
Activity Detection ◽  
Reaction Products ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Salsolinol Synthase

AbstractSalsolinol (1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline; Sal) is structurally similar to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, which is supposed to have a role in the development of Parkinson-like syndrome in both human and non-human subjects. In the human brain, the amount of (R)-enantiomer of Sal is much higher than (S)-enantiomer, suggesting that a putative enzyme may participate in the synthesis of (R)-salsolinol, called (R)-salsolinol synthase. In this study, the (R)-salsolinol synthase activity in the condensation of dopamine and acetaldehyde was investigated in the crude extracts from the brains of Sprague Dawley rats. Identification of the enzymatic reaction products and enzyme activity detection were achieved by HPLC-electrochemical detection. The discovery of this enzyme activity in rat’s brain indicates the natural existence of (R)-salsolinol synthase in the brains of humans and rats, and it is distributed in most brain regions of rat with higher activity in soluble proteins extracted from striatum and substantia nigra.

scholarly journals Tuning the near infrared II emitting wavelength of small molecule dyes by single atom alteration

2020 ◽  
Vol 56 (4) ◽  
pp. 523-526 ◽  
Author(s):  
Kun Qian ◽  
Chunrong Qu ◽  
Xiangyu Ma ◽  
Hao Chen ◽  
Martha Kandawa-Schulz ◽  
...  
Keyword(s):  
Small Molecule ◽  
Near Infrared ◽  
Fluorescence Emission ◽  
Red Shift ◽  
Single Atom

Replacing donors’ S with O and Se will red shift NIR-II dyes’ fluorescence emission and offer good clarity/brightness for imaging.

Synthesis, characterization and fluorescence properties study of meso-tetrakis(1-arylpyrazole-4-yl)porphyrins

2005 ◽  
Vol 09 (06) ◽  
pp. 430-435 ◽  
Author(s):  
Can-Cheng Guo ◽  
Tie-Gang Ren ◽  
Jian Wang ◽  
Chun-Yan Li ◽  
Jian-Xin Song
Keyword(s):  
Elemental Analysis ◽  
Mass Spectra ◽  
Fluorescence Spectra ◽  
Fluorescence Emission ◽  
Red Shift ◽  
Fluorescence Properties ◽  
Quantum Yields ◽  
Fluorescence Quantum Yields ◽  
H Nmr ◽  
Reaction Condition

Five new meso-tetrakis(1-arylpyrazol-4-yl)porphyrins were synthesized to investigate their fluorescence properties. Preparation of these porphyrins was carried out by cyclization of tetramethoxypropane with substituted phenylhydrazine, followed by formylation to give the corresponding aldehydes, which reacted with pyrrole under the Adler reaction condition to get the target porphyrins (1a-1e). All the porphyrins were characterized by 1 H NMR, elemental analysis, UV-vis spectra and mass spectra. Red fluorescence emission of these porphyrins was observed in fluorescence spectra. Compared with meso-tetraphenylporphyrin (TPPH2), these meso-tetrakis(1-arylpyrazol-4-yl) porphyrins had a significant red shift in UV-vis and fluorescence spectra with increased fluorescence quantum yields.

Multicarbazolyl substituted TTM radicals: red-shift of fluorescence emission with enhanced luminescence efficiency

2017 ◽  
Vol 1 (10) ◽  
pp. 2132-2135 ◽  
Author(s):  
Shengzhi Dong ◽  
Ablikim Obolda ◽  
Qiming Peng ◽  
Yadong Zhang ◽  
Seth Marder ◽  
...  
Keyword(s):  
Fluorescence Emission ◽  
Red Shift ◽  
Luminescence Efficiency ◽  
Enhanced Luminescence

Rotation restricted multicarbazolyl substituted TTM radicals: red-shift of fluorescence emission with enhanced luminescence efficiency.

scholarly journals Fluorescence anisotropy imaging of a polydiacetylene photopolymer film

2019 ◽  
Vol 97 (6) ◽  
pp. 422-429
Author(s):  
Hamid Soleimaninejad ◽  
Kenneth P. Ghiggino ◽  
Trevor A. Smith ◽  
Matthew F. Paige
Keyword(s):  
Conjugated Polymers ◽  
Single Molecule ◽  
Fluorescence Anisotropy ◽  
Fluorescence Emission ◽  
Future Studies ◽  
Preparation Conditions ◽  
Uv Illumination ◽  
Emission Transition ◽  
The Individual ◽  
Defocused Imaging

UV-illumination of phase-separated surfactant films prepared from mixtures of photopolymerizable 10,12-pentacosadiynoic acid and perfluorotetradecanoic acid results in the formation of fluorescent polydiacetylene fibers and aggregates. In this work, the orientation of polymer strands that comprise the resulting photopolymer structures has been probed using fluorescence anisotropy imaging in combination with defocused single-molecule fluorescence imaging. Imaging experiments indicate the presence of significant fiber-to-fiber heterogeneity, as well as anisotropy within each fiber (or aggregate), with both of these properties changing as a function of film preparation conditions. This anisotropy can be attributed to various alignments of the constituent polymer strands that comprise the larger fibers and aggregates. Intriguingly, when using defocused imaging, fiber images consisted of a series of discrete “doughnut” fluorescence emission patterns, which exhibited intermittent on–off blinking behavior; both of these properties are characteristic of individual emission transition dipoles (single molecules). Further, all of the individual emission transition dipoles had a uniform orientation with respect to the axis of the fiber, indicating a common orientation of discrete emitters in the larger polymer fiber. The implications of these results for future studies of the electronic properties of conjugated polymers in larger macroscopic systems are noted.

scholarly journals Highly Sensitive Detection of Benzoyl Peroxide Based on Organoboron Fluorescent Conjugated Polymers

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1655 ◽  
Author(s):  
Mingyuan Yin ◽  
Caiyun Zhang ◽  
Jing Li ◽  
Haijie Li ◽  
Qiliang Deng ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Benzoyl Peroxide ◽  
Boronic Acid ◽  
Limit Of Detection ◽  
Fluorescence Emission ◽  
High Sensitivity ◽  
Ammonium Persulfate ◽  
Sensitive Detection ◽  
Polymerization Reaction ◽  
Charge Transfer Complexes

The method capable of rapid and sensitive detection of benzoyl peroxide (BPO) is necessary and receiving increasing attention. In consideration of the vast signal amplification of fluorescent conjugated polymers (FCPs) for high sensitivity detection and the potential applications of boron-containing materials in the emerging sensing fields, the organoboron FCPs, poly (3-aminophenyl boronic acid) (PABA) is directly synthesized via free-radical polymerization reaction by using the commercially available 3-aminophenyl boronic acid (ABA) as the functional monomer and ammonium persulfate as the initiator. PABA is employed as a fluorescence sensor for sensing of trace BPO based on the formation of charge-transfer complexes between PABA and BPO. The fluorescence emission intensity of PABA demonstrates a negative correlation with the concentration of BPO. And a linear range of 8.26 × 10−9 M–8.26 × 10–4 M and a limit of detection of 1.06 × 10–9 M as well as a good recovery (86.25%–111.38%) of BPO in spiked real samples (wheat flour and antimicrobial agent) are obtained. The proposed sensor provides a promising prospective candidate for the rapid detection and surveillance of BPO.

Temperature Dependent Conformation Changes of Ribulose-1,5-bisphosphate Carboxylase Studied by the Use of 1-Anilino-8-naphthalene Sulfonate

1977 ◽  
Vol 32 (3-4) ◽  
pp. 226-228 ◽  
Author(s):  
Günter F. Wildner ◽  
Jürgen Henkel
Keyword(s):  
Enzyme Activity ◽  
Binding Sites ◽  
Fluorescence Probe ◽  
Fluorescence Emission ◽  
Binding Constants ◽  
Temperature Dependent ◽  
Bisphosphate Carboxylase ◽  
Influence Of Temperature On ◽  
Number Of Binding Sites ◽  
Enzyme Molecules

Abstract The influence of temperature on the structure and enzyme activity of ribulose-1,5-bisphosphate carboxylase, isolated from Euglena gracilis cells, was studied. Freezing of the purified ribulose-1,5-bisphosphate carboxylase preparation causes a severe loss of enzyme activity, which can be restored again by incubation of the enzyme molecules at higher temperatures (50 °C). The titration of both enzyme samples with the fluorescence probe 1-anilino-8-naphthalene sulfonate (ANS) re­vealed an increase of the fluorescence emission of the low temperature form of the enzyme. Two different enzyme conformations can be assumed which differ in the number of binding sites for ANS and Vmax values for the carboxylase reaction but show similar binding constants for ANS and the apparent Km values for C02 .

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