The present invention provides for water-soluble mono- and dicationic fluorescent dyes with the latter exhibiting stable fluorescence at elevated temperatures. The present invention also provides for methods for the production of the fluorescent dyes and for using these dyes in biological assays such as multiplexing qPCR and tissue staining.

The present invention provides for water-soluble mono- and dicationic fluorescent dyes with the latter exhibiting stable fluorescence at elevated temperatures. The present invention also provides for methods for the production of the fluorescent dyes and for using these dyes in biological assays such as multiplexing qPCR and tissue staining.

A novel non-fluorescent rhodamine dye forms a twisted intramolecular charge transfer state. A substituent that causes steric hindrance is introduced at an ortho position of a dimethylamino group on the xanthene ring of tetramethylrhodamine, which is a general rhodamine that exhibits strong fluorescence, and a certain amount of twist is imparted in a ground state. As a result, the formation of the twisted intramolecular charge transfer state is promoted in the excited state and non-fluorescence is exhibited.

Provided are a photoactive fluorophore, a photoactive ligand, and a photoactive complex. The photoactive fluorophore includes a photoactivatable derivative of an azetidine-containing Janelia-Fluor dye. The photoactive ligand includes a photoactive fluorophore and a protein tag. The photoactive complex includes a photoactive ligand conjugated to a protein. Also provided are methods of in vivo labeling with and photoactivation of the photoactive fluorophore, ligand, and complex.

Provided are a photoactive fluorophore, a photoactive ligand, and a photoactive complex. The photoactive fluorophore includes a photoactivatable derivative of an azetidine-containing Janelia-Fluor dye. The photoactive ligand includes a photoactive fluorophore and a protein tag. The photoactive complex includes a photoactive ligand conjugated to a protein. Also provided are methods of in vivo labeling with and photoactivation of the photoactive fluorophore, ligand, and complex.

The present invention relates to a compound of the following formula (I). The invention also relates to uses thereof as a chromophore as such or for building pigments displaying special optical effects, including metal-like reflection. ##STR00001##

The present invention relates to a compound of the following formula (I). The invention also relates to uses thereof as a chromophore as such or for building pigments displaying special optical effects, including metal-like reflection. ##STR00001##

Provided herein are novel photoactive fluorescent compounds and their use in labeling proteins, for example, tagged proteins, and their use for visualizing the location and dynamics of proteins in living cells.

Provided herein are novel photoactive fluorescent compounds and their use in labeling proteins, for example, tagged proteins, and their use for visualizing the location and dynamics of proteins in living cells.

The invention relates to novel fluorescent rhodamine dyes with enhanced cell permeability which are rhodamine 4′-isomers having the following general structural formula A: wherein Z is selected from O(alkyl), O(aryl), S(aryl), S(O)(alkyl), S(O) (aryl), S(O).sub.2(alkyl), S(O).sub.2(aryl), S(O).sub.2(—O-alkyl), S(O).sub.2(—O-aryl), S(O).sub.2NH(alkyl), S(O).sub.2NH(aryl), S(O).sub.2N(alkyl).sub.2, S(O).sub.2N(aryl).sub.2, S(O).sub.2N(alkyl)(aryl), C(O)O(alkyl), C(O)O(aryl), C(O)(alkyl), C(O)(aryl), P(O)OH(—NH-alkyl), P(O)OH(—O-alkyl), P(O)OH(—NH-aryl), P(O)OH(—O-aryl), P(O)(—O-alkyl).sub.2, P(O)(—NH-alkyl).sub.2, P(O)OH(—N(alkyl).sub.2), P(O)OH(—N(aryl).sub.2), P(O)(—N(aryl).sub.2).sub.2, P(O) (—N(alkyl).sub.2)(—N(alkyl).sub.2), P(O)(—O-aryl).sub.2, P(O)(—NH-aryl).sub.2, P(O)(—O-alkyl)(-O-aryl), P(O)(—NH-alkyl)(-O-aryl), P(O)(-O-alkyl)(-NH-aryl), P(O)(—NH-alkyl)(-NH-aryl), C(O)OH, C(O)NH(alkyl), C(O)NH(aryl), CON(alkyl).sub.2, CON(aryl).sub.2, in particular C(O)OH, C(O)NH(alkyl), C(O)NH(aryl), CON(alkyl).sub.2, CON(aryl).sub.2, C(O)O(alkyl) and C(O)O(aryl), or any group which is neither Cl, NH.sub.2 or NO.sub.2 and which induces a neighboring group effect via steric, ionic or bonding interactions with the adjacent carboxyl group resulting in a shift of the equilibrium between zwitterionic form and spirolactone form towards the spirolactone form. The invention further relates to 4′-isomer derivatives and probes comprising such 4′-isomers coupled to at least one reactive group or ligand which is capable to interact with or bind to other molecules, wherein said reactive group or ligand may be coupled to the rhodamine 4′-isomer fluorophore either directly or via a linker. Another aspect of the invention relates to the use of these compounds and conjugates as labels in microscopic, spectroscopic and other imaging techniques and/or as cell permeable substances penetrating through membranes of living and fixed cells in vivo or in vitro.

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