Multivalent fluorescent probes

A method of detecting light from a sample or subject, the method comprising (a) administering to the sample or subject one or more multivalent fluorescent probes having the structure:

• wherein X and Y are O, S, Se or CR15R16;
• n is 0 to 3;
• R1 to R11, and R13-16 are independently selected from the group consisting of hydrogen, alkyl having 1 to 20 carbons, alkoxy having 1 to 20 carbons, trifluoromethyl, halogen, methylthio, sulfonyl, carbonyl, hydroxy, amino and thiol;
• wherein R represents a targeting moiety and the four targeting moieties are linked to X, Y, N and N+ via the L1, L2, L3 and L4, wherein L1, L2, L3, and L4 are linkers and comprise 10 to 50 linear atoms selected from carbon, nitrogen, oxygen, phosphorus and sulfur that are further substituted by hydrogen, alkyl having from 1 to 20 carbons, alkoxy having from 1 to 20 carbons, trifluoromethyl, halogen, methylthio, sulfonyl, carbonyl, hydroxy, amino, thiol, amino acid residues RGD, zinc (Zn) or a ligand that binds to a cell surface receptor;
• wherein the probe emits light having a wavelength of 550 to 1200 nm and wherein the targeting moiety is a molecule that specifically targets the multivalent fluorescent probe to a specific cell present in the sample or the subject;
• (b) exposing the sample or subject to light of a wavelength of light that excites the fluorochrome of the fluorescent probe;
• and
• (c) detecting light emitted by the fluorescent probe.