Molecular probes for multimodality imaging and tracking of stem cells

A method for performing cell therapy, comprising:

• administering to a subject cells labeled with a compound having the formula:
• wherein
• B is a chelating moiety capable of complexing to a radioactive metal;
• R and R1 are substituent groups independently selected from the group consisting of alkyl, alkenyl, alkynyl, alkaryl and aralkyl, each of R and R1 comprising one or more linear or branched hydrocarbon chains having from about 2 to about 30 carbon atoms, and each of R and R1 being unsubstituted or substituted with one or more non-polar functional groups;
• L comprises a fluorophore with emission in the range from about 650 nm to about 850 nm;
• R2 is a spacer moiety having the formula:
• —(R3)p-Q-(R4-Q′)q-(R5-Q″)r-(R6-Q′″)s-(R7Q″″)t,
• wherein
• R3 is an aliphatic hydrocarbon, R4, R5, R6 and R7 are independently selected from the group consisting of aliphatic, alicyclic or aromatic hydrocarbons, heterocycles or CH2C(CO2H)═CH,
• Q, Q′, Q″, Q′″ and Q″″ are linking groups independently selected from the group consisting of amide, thiourea, hydrazone, acylhydrazone, ketal, acetal, orthoester, ester, anhydride, disulfide, urea, carbamate, imine, amine, ether, carbonate, thioether, sulfonamide, carbonyl, amidine and triazine, a valence bond, the aliphatic or alicyclic hydrocarbons having from about 1 to about 12 linear carbon atoms, and the aromatic hydrocarbons having from about 6 to about 12 carbon atoms;
• p, q, r, s and t each is 0 or 1;
• and
• n is 0 or 1;
• and
• tracking the cells via two or more modalities comprising optical imaging and radiological imaging of the labeled cells.