Novel Fluorescent Probe Based on Anthryl Dendron Having Oligo(ethyleneoxide) Groups at the Terminals

Amphiphilic anthryl dendrons 5 and 6, which have carboxylate groups or oligo(ethyleneoxide) groups at the terminals, show solvatochromic properties. Reaction efficiency of photodimerization and dynamic light scattering (DLS) experiment of 5 and 6 reveal that formation of the aggregate of dendrons 5 or 6 plays a crucial role in this solvatochromism. Interestingly, solvatochromic property of anthryl dendron 6 was useful for determination of the ratio of methanol/water in solution as a fluorescent probe

Determination of the Critical Micelle Concentration of Triton X-100 Using the Compound 3-(benzoxazol-2-yl)-7-(N,N-diethylamino)chromen-2-one as Fluorescent Probe

In the present study we estimated the Critical Micelle Concentration (CMC) of Triton X-100 in an aqueous buffered medium (PBS buffer, pH 7.4), using 3-(benzoxazol-2-yl)-7-(N,N-diethylamino)chromen-2-one (BDC), a push-pull compound, as extrinsic fluorescence probe. The CMC value found, 0.33 mmol L-1, shows good agreement with data from literature obtained using the fluorescence probe technique. Additionally, the polarity, in terms of the ET(30) scale, and the viscosity of the micelle microenvironment in which the probe is preferentially allocated, was estimated as being 46.9 kcal mol-1 and 70.3 cP, respectively, confirming that this microdomain is polar and highly viscous, with characteristics of polyethylene glycol groups consisting in the palisade layer at the micelle-water interface. DOI: http://dx.doi.org/10.17807/orbital.v0i0.92

A ratiometric Al³⁺ ion probe based on the coumarin-quinoline FRET system

A coumarin-quinoline based fluorescence resonance energy transfer (FRET) system (TCQ) has been synthesized and employed as a ratiometric fluorescence probe. The selective fluorescent response of the probe TCQ toward Al³⁺ was devised by employing a quinoline moiety as a FRET energy donor with a coumarin moiety as an energy acceptor. The quinoline emission at 390 nm decreased and the coumarin emission at 480 nm increased concurrently on addition of Al³⁺ under excitation wavelength at 253 nm. The TCQ probe exhibited high selectivity for Al³⁺ as compared to other tested metal ions and the ratiometric sensing of Al³⁺ was determined by plotting the fluorescence intensity ratio at 480 nm and 390 nm versus Al³⁺ ion concentration. Moreover, test strips based on TCQ were fabricated, which were found to act as a convenient and efficient Al³⁺ ion detection kit. Furthermore, this system has been used for imaging of Al³⁺ in living cells

Toward an Alternative Intrinsic Probe for Spectroscopic Characterization of a Protein

The intrinsic fluorescent amino acid tryptophan is the unanimous choice for the spectroscopic investigation of proteins. However, several complicacies in the interpretation of tryptophan fluorescence in a protein are inevitable and an alternative intrinsic protein probe is a longstanding demand. In this contribution, we report an electron-transfer reaction in a human transporter protein (HSA) cavity which causes the tryptophan residue (Trp214) to undergo chemical modification to form one of its metabolites kynurenine (Kyn214). Structural integrity upon modification of the native protein is confirmed by dynamic light scattering (DLS) as well as near and far circular dichroism (CD) spectroscopy. Femtosecond-resolved fluorescence transients of the modified protein describe the dynamics of solvent molecules in the protein cavity in both the native and denatured states. In order to establish general use of the probe, we have studied the dipolar interaction of Kyn214 with a surface-bound ligand (crystal violet, CV) of the protein. By using the sensitivity of FRET, we have determined the distance between Kyn214 (donor) and CV (acceptor). Our study is an attempt to explore an alternative intrinsic fluorescence probe for the spectroscopic investigation of a protein. In order to establish the efficacy of the modification technique we have converted the tryptophan residues of other proteins (bovine serum albumin, chymotrypsin and subtilisin Carlsberg) to kynurenine and confirmed their structural integrity. We have also shown that catalytic activity of the enzymes remains intact upon the modification

Preparation and Characterization of Fluorescence Probe from Assembly Hydroxyapatite Nanocomposite

A new nanocomposite fluorescence probe with thioglycolic acid (TA) functional layers embedded inside the hydroxyapatite nanoribbon spherulites has been synthesized. The fluorescence intensity of the novel probe is about 1.5–3.3-fold increase compared with the probe containing no TA. When used to detect cadmium ion, the most of original assembly nanoribbon spherulites structure in the novel probe is found to have been damaged to new flake structures. The mechanism of determining cadmium ion in alcohol solution has been studied. The present systematic study provides significant information on the effect of assembly nanostructure on the metal-enhanced fluorescence phenomenon

G-Quadruplex Visualization in Cells via Antibody and Fluorescence Probe

G-quadruplexes (G4s) are noncanonical nucleic acids structures involved in key regulatory and pathological roles in eukaryotes, prokaryotes, and viruses: the development of specific antibodies and fluorescent probes represent an invaluable tool to understand their biological relevance. We here present three protocols for the visualization of G4s in cells, both uninfected and HSV-1 infected, using a specific antibody and a fluorescent G4 ligand, and the effect of the fluorescent ligand on a G4 binding protein, nucleolin, upon binding of the molecule to the nucleic acids structure

Fluorescence probe for determining the ozone dose delivered by plasmas

Plasma composition is typically studied by absorption and emission spectroscopy, mass spectrometry and computational studies. While these techniques provide valuable information about the chemical species in the gas phase, in many applications it is desirable to have a direct measurement of the dose of chemical species delivered to a particular target. In this work, we will use a fluorescent chemical probe in order to characterize actual flux of ozone experienced by a target exposed to plasma