ABSTRACT
Triphenylamine-sensitized 8-dimethylaminoquinoline (TAQ) probes showed fair two-photon absorption and fragmentation cross sections in releasing kainate and GABA ligands. The water-soluble PEG and TEG-analogs allowed cell internalization and efficient light-gated liberation of the rhodamine reporter under UV and two-photon (NIR) irradiation conditions.
ABSTRACT
An efficient nano-sized delivery system is presented here allowing the immobilized, picolinium-tethered organic ligand to be released by X-ray irradiation. A marked difference was observed in the fragmentation efficiency by using conventional Cs-137 vs. pulsed sources.
ABSTRACT
The photolysis of covalently linked N-alkyl picolinium phenylacetate-carbazole dyads was analyzed experimentally and by using density functional theory (DFT) and time dependent-DFT (TD-DFT) calculations. In contrast to earlier observations efficient one and two-photon fragmentations conditions were found for 15 c (δu =0.16â GM at 730â nm) opening the way for the design of a novel class of "caged" compounds.
ABSTRACT
A systematic study on quinoline-derived light sensitive probes, having third-order rotational symmetry is presented. The electronically linked octupolar structures show considerably improved linear and nonlinear photophysical properties under one- and two-photon irradiation conditions compared to the corresponding monomers. Photolysis of the three acetate derivatives shows strong structure dependency: whereas irradiation of the 6- and 7-aminoquinoline derivatives resulted in fast intramolecular cyclization and only trace amounts of fragmentation products, the 8-aminoquinoline derivative afforded clean and selective photolysis, with a sequential release of their acetate groups (δu[730]=0.67â GM).
ABSTRACT
Quadrupolar probes derived from 8-dimethylamino-quinoline (8-DMAQ) having a pegylated fluorene core were prepared and studied under "one-photon" (λ=365â nm) and "two-photon" (TP) (λ=730â nm) irradiation conditions. Compound 1 a was identified as the most efficient probe by UV activation that showed sequential release of acetic acid as a model. Although the probe showed high two-photon absorption it stayed inert under femtosecond irradiation conditions. Fast and selective photolysis was observed, however, by using picosecond irradiation conditions with a remarkably high TP uncaging cross-section (δu =2.3â GM).
ABSTRACT
Photolysis of microdroplets, stabilized by aminoquinoline-derived photosensitive surfactants composed of polyethyleneglycol/perfluorinated polyether (PEG/PFPE) diblock amphiphiles by using 355 nm ps pulsed laser light, resulted in rapid controlled coalescence of targeted microdroplets offering the prospect of a novel type of droplet merging with high stereospatial integrity for microfluidic systems.
ABSTRACT
High two-photon photolysis cross sections and water solubility of probes are important to avoid toxicity in biomedical applications of photolysis. Systematic variation of the position of a carboxyl electron-withdrawing group (EWG) on photolysis of 8-dimethylaminoquinoline protecting groups identified the C5-substituted isomer as a privileged dipole. The 5-benzoyl-8-DMAQ substitution yields a caging group with an enhanced two-photon uncaging cross section (δu = 2.0 GM) and good water solubility (c ≤ 50 mM, pH 7.4).
Subject(s)
Aminoquinolines/chemistry , Photolysis , Photons , Molecular Structure , SolubilityABSTRACT
The first quadrupolar 8-dimethylaminoquinoline-derived 6-(8-DMAQ-OAc)2 (1c) and 5-(8-DMAQ-OAc)2 (2c) photosensitive probes underwent photolysis under UV (365 nm) and NIR (730 nm two-photon (TP)) irradiation conditions, showing Qu = 9.3% and 6.6% quantum yields and δu = 0.07 GM and 0.40 GM uncaging cross-sections, respectively.
Subject(s)
Photons , Photosensitizing Agents/chemistry , Quinolines/chemistry , Molecular Structure , PhotolysisABSTRACT
The systematic SAR study of a "caging" group showed a strong influence of the position of the donor dimethylamino group on the efficiency of photolysis of the DMAQ (2-hydroxymethylene-(N,N-dimethylamino)quinoline) caged acetate under one-photon near-UV or two-photon near-IR excitation. Photorelease of l-glutamate by the most efficient 8-DMAQ derivative strongly and efficiently activated glutamate receptors, generating large, fast rising responses similar to those elicited by glutamate photoreleased from the widely used MNI-caged glutamate.
Subject(s)
Glutamates/chemistry , Photons , Quinolines/chemistry , Molecular Structure , Photolysis , Structure-Activity RelationshipABSTRACT
We report the structure-based design and synthesis of a unique NOS inhibitor, called nanoshutter NS1, with two-photon absorption properties. NS1 targets the NADPH site of NOS by a nucleotide moiety mimicking NADPH linked to a conjugated push-pull chromophore with nonlinear absorption properties. Because NS1 could not provide reducing equivalents to the protein and competed with NADPH binding, it efficiently inhibited NOS catalysis. NS1 became fluorescent once bound to NOS with an excellent signal-to-noise ratio because of two-photon excitation avoiding interference from the flavin-autofluorescence and because free NS1 was not fluorescent in aqueous solutions. NS1 fluorescence enhancement was selective for constitutive NOS in vitro, in particular for endothelial NOS (eNOS). Molecular dynamics simulations suggested that two variable residues among NOS isoforms induced differences in binding of NS1 and in local solvation around NS1 nitro group, consistent with changes of NS1 fluorescence yield. NS1 colocalized with eNOS in living human umbilical vein endothelial cells. Thus, NS1 constitutes a unique class of eNOS probe with two-photon excitation in the 800-950-nm range, with great perspectives for eNOS imaging in living tissues.
Subject(s)
Fluorescent Dyes , Human Umbilical Vein Endothelial Cells/enzymology , Microscopy, Fluorescence, Multiphoton/methods , NADP , Nitric Oxide Synthase Type III , Catalysis , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/chemistry , Fluorescent Dyes/pharmacology , Human Umbilical Vein Endothelial Cells/chemistry , Human Umbilical Vein Endothelial Cells/cytology , Humans , Isoenzymes/chemistry , Isoenzymes/metabolism , Molecular Dynamics Simulation , NADP/analogs & derivatives , NADP/chemical synthesis , NADP/chemistry , NADP/pharmacology , Nitric Oxide/biosynthesis , Nitric Oxide/chemistry , Nitric Oxide Synthase Type III/chemistry , Nitric Oxide Synthase Type III/metabolismABSTRACT
Various substituents could be diastereoselectively introduced into the 5-position of pipecolic acid via electrophilic or free-radical-initiated addition to the carbon-carbon double bond of endocyclic enecarbamates derived from pipecolic acid. This study allowed the diastereoselective synthesis of both cis- and trans-5-guanidino pipecolates, which were designed as constrained arginine mimetics and whose potential inhibition of nitric oxide synthase (NOS) was evaluated with three NOS isoforms.