Abstract: The invention relates to activatable imaging probes that includes a chromophore attachment moiety and one or more, e.g., a plurality of, chromophores, such as near-infrared chromophores, chemically linked to the chromophore attachment moiety so that upon activation of the imaging probe the optical properties of the plurality of chromophores are altered. The probe optionally includes protective chains or chromophore spacers, or both. Also disclosed are methods of using the imaging probes for optical imaging.

Abstract: Nucleic acid-imaging compositions and methods for noninvasive imaging of a nucleic acid introduced into somatic tissues of an animal or human are disclosed. The noninvasive imaging enables quantitative assessment of the biodistribution of the introduced nucleic acid. The disclosed imaging compounds include a base-binding moiety, a phosphate-binding moiety, and a metal-binding moiety. A chelated metal is non-invasively detected for imaging by radioactivity or magnetic resonance.

Abstract: An intramolecularly-quenched, near infrared fluorescence probe that emits substantial fluorescence only after interaction with a target tissue (i.e., activation) is disclosed. The probe includes a polymeric backbone and a plurality of near infrared fluorochromes covalently linked to the backbone at fluorescence-quenching interaction-permissive positions separable by enzymatic cleavage at fluorescence activation sites. The probe optionally includes protective chains or fluorochrome spacers, or both. Also disclosed are methods of using the intramolecularly-quenched, near infrared fluorescence probes for in vivo optical imaging.