We have been investigating the rational design and in vivo applications of target-cell specific activatable probes. Designing these probes based on their photo-chemical (e.g. activation strategy), pharmacological (e.g. biodistribution), and biological (e.g. target specificity) properties has recently allowed the rational design and synthesis of target-cell specific activatable fluorescence imaging probes, which can be conjugated to a wide variety of targeting molecules. Several different photo-chemical mechanisms have been utilized, each of which offers a unique capability for probe design. These include: self-quenching, homo- and hetero-fluorescence resonance energy transfer (FRET), H-dimer formation and photon-induced electron transfer (PeT). In addition, the repertoire is further expanded by the option for reversibility or irreversibility of the signal emitted using the aforementioned mechanisms. Given the wide range of photochemical mechanisms and properties, target-cell specific activatable probes possess considerable flexibility and can be adapted to specific diagnostic needs. From a translational viewpoint, including considerations of both the clinical value and regulatory approval requirements, several clinically applicable candidates including indocyanine green labeled antibodies or a small molecular gamma-glutamyltransferase activatable probe, which are designed to be used during surgical or endoscopic procedures, have been tested.
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|Sano, Kohei; Nakajima, Takahito; Miyazaki, Kiminori et al. (2013) Short PEG-linkers improve the performance of targeted, activatable monoclonal antibody-indocyanine green optical imaging probes. Bioconjug Chem 24:811-6|
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