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Proceedings Paper

Time-domain imaging with quench-based fluorescent contrast agents
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Paper Abstract

Quench-based probes utilize unique characteristics of fluorescence resonance energy transfer (FRET) to enhance contrast upon de-quenching. This mechanism has been used in a variety of molecular probes for imaging of cancer related enzyme activity such as matrix metalloproteinases, cathepsins and caspases. While non-fluorescent upon administration, fluorescence can be restored by separation of donor and acceptor, resulting in higher intensity in the presence of activator. Along with decreased quantum yield, FRET also results in altered fluorescence lifetime. Time-domain imaging can further enhance contrast and information yield from quench-based probes. We present in vivo time-domain imaging for detecting activation of quench-based probes. Quench-based probes utilize unique characteristics of fluorescence resonance energy transfer (FRET) to enhance contrast upon de-quenching. This mechanism has been used in a variety of molecular probes for imaging of cancer related enzyme activity such as matrix metalloproteinases, cathepsins and caspases. While non-fluorescent upon administration, fluorescence can be restored by separation of donor and acceptor, resulting in higher intensity in the presence of activator. Along with decreased quantum yield, FRET also results in altered fluorescence lifetime. Time-domain imaging can further enhance contrast and information yield from quench-based probes. We present in vivo time-domain imaging for detecting activation of quench-based probes. Time-domain diffuse optical imaging was performed to assess the FRET and quenching in living mice with orthotopic breast cancer. Tumor contrast enhancement was accompanied by increased fluorescence lifetime after administration of quenched probes selective for matrix metalloproteinases while no significant change was observed for non-quenched probes for integrin receptors. These results demonstrate the utility of timedomain imaging for detection of cancer-related enzyme activity in vivo.

Paper Details

Date Published: 2 February 2012
PDF: 7 pages
Proc. SPIE 8233, Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications IV, 82330G (2 February 2012); doi: 10.1117/12.915917
Show Author Affiliations
Walter J. Akers, Washington Univ. School of Medicine in St. Louis (United States)
Metasebya Solomon, Washington Univ. School of Medicine in St. Louis (United States)
Gail P. Sudlow, Washington Univ. School of Medicine in St. Louis (United States)
Mikhail Berezin, Washington Univ. School of Medicine in St. Louis (United States)
Samuel Achilefu, Washington Univ. School of Medicine in St. Louis (United States)


Published in SPIE Proceedings Vol. 8233:
Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications IV
Samuel Achilefu; Ramesh Raghavachari, Editor(s)

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