Charged-balanced imaging agents
View Patent ↗The present invention relates to compositions and methods of optically imaging tissues or cells using imaging agents have in vivo properties that result in signal-to-background ratios of at least about 1:1. TL is a targeting ligand and n is −1, 0 or +1.
1. A method of imaging tissue or cells, the method comprising:
(a) contacting the tissue or cells with an imaging agent comprising a dye;
(b) irradiating the tissue or cells at a wavelength absorbed by the dye;
(c) detecting an optical signal from the irradiated tissue or cells, wherein the signal-to-background ratio of the detected optical signal is at least about 1.1, thereby imaging the tissue or cells;
wherein the dye has the formula X:
or an ester thereof, which permits covalent conjugation of the fluorophore to targeting ligands.
2. A dye, having the formula X:
or an ester, an acid, a salt, or a combination of an acid or a salt, thereof, which permits covalent conjugation of the fluorophore to targeting ligands.
3. The dye of claim 2 , wherein the ester is a N-hydroxysuccinimide ester.
4. The dye of claim 2 , wherein the dye is a salt, an acid, or a combination of a salt and an acid.
5. A method of imaging tissue or cells, the method comprising:
(a) contacting the tissue or cells with an imaging agent comprising a conjugate of a dye;
(b) irradiating the tissue or cells at a wavelength absorbed by the conjugate;
(c) detecting an optical signal from the irradiated tissue or cells, wherein the signal-to-background ratio of the detected optical signal is at least about 1.1, thereby imaging the tissue or cells;
wherein the conjugate has the formula VII:
Wherein n is 0, +1, or −1; and
TL is a targeting ligand.
6. A conjugate having the formula VII:
Wherein n is 0, +1, or −1; and
TL is a targeting ligand.
7. An imaging agent comprising the conjugate of claim 6 which is characterized as having detectable fluorescence with a signal-to-background ratio of at least about 1.1.