Limits...
MMP-2/9-Specific Activatable Lifetime Imaging Agent.

Rood MT, Raspe M, ten Hove JB, Jalink K, Velders AH, van Leeuwen FW - Sensors (Basel) (2015)

Bottom Line: Ir(ppy)3 and Cy5 were used because in close proximity the emission intensities of both luminophores were quenched and the influence of Cy5 shortens the Ir(ppy)3 luminescence lifetime from 98 ns to 30 ns.Upon cleavage in vitro, both effects are undone, yielding an increase in Ir(ppy)3 and Cy5 luminescence and a restoration of Ir(ppy)3 luminescence lifetime to 94 ns.As a reference for the luminescence activation, a similar imaging agent with the more common Cy3-Cy5 fluorophore pair was used.

View Article: PubMed Central - PubMed

Affiliation: Interventional Molecular Imaging Laboratory, Department of Radiology, Leiden University Medical Center, Leiden 2300RC, The Netherlands. m.t.m.rood@lumc.nl.

ABSTRACT
Optical (molecular) imaging can benefit from a combination of the high signal-to-background ratio of activatable fluorescence imaging with the high specificity of luminescence lifetime imaging. To allow for this combination, both imaging techniques were integrated in a single imaging agent, a so-called activatable lifetime imaging agent. Important in the design of this imaging agent is the use of two luminophores that are tethered by a specific peptide with a hairpin-motive that ensured close proximity of the two while also having a specific amino acid sequence available for enzymatic cleavage by tumor-related MMP-2/9. Ir(ppy)3 and Cy5 were used because in close proximity the emission intensities of both luminophores were quenched and the influence of Cy5 shortens the Ir(ppy)3 luminescence lifetime from 98 ns to 30 ns. Upon cleavage in vitro, both effects are undone, yielding an increase in Ir(ppy)3 and Cy5 luminescence and a restoration of Ir(ppy)3 luminescence lifetime to 94 ns. As a reference for the luminescence activation, a similar imaging agent with the more common Cy3-Cy5 fluorophore pair was used. Our findings underline that the combination of enzymatic signal activation with lifetime imaging is possible and that it provides a promising method in the design of future disease specific imaging agents.

Show MeSH
Synthesis of the activatable imaging agents discussed in this research. (a) Cy5, PyBOP, DIPEA, DMF; (b) TFA, H2O, TIS; (c) Cy3-NHS, H2O/DMSO; (d) Ir(ppy)3-β-Ala-COOH, DCC, NHS, H2O/DMSO. The amino acid sequence for cleavage is highlighted in red and comprised of either l-amino acid or d-amino acids. All other amino acids used to generate these structures were d-amino acids.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4481940&req=5

sensors-15-11076-f007: Synthesis of the activatable imaging agents discussed in this research. (a) Cy5, PyBOP, DIPEA, DMF; (b) TFA, H2O, TIS; (c) Cy3-NHS, H2O/DMSO; (d) Ir(ppy)3-β-Ala-COOH, DCC, NHS, H2O/DMSO. The amino acid sequence for cleavage is highlighted in red and comprised of either l-amino acid or d-amino acids. All other amino acids used to generate these structures were d-amino acids.


MMP-2/9-Specific Activatable Lifetime Imaging Agent.

Rood MT, Raspe M, ten Hove JB, Jalink K, Velders AH, van Leeuwen FW - Sensors (Basel) (2015)

Synthesis of the activatable imaging agents discussed in this research. (a) Cy5, PyBOP, DIPEA, DMF; (b) TFA, H2O, TIS; (c) Cy3-NHS, H2O/DMSO; (d) Ir(ppy)3-β-Ala-COOH, DCC, NHS, H2O/DMSO. The amino acid sequence for cleavage is highlighted in red and comprised of either l-amino acid or d-amino acids. All other amino acids used to generate these structures were d-amino acids.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481940&req=5

sensors-15-11076-f007: Synthesis of the activatable imaging agents discussed in this research. (a) Cy5, PyBOP, DIPEA, DMF; (b) TFA, H2O, TIS; (c) Cy3-NHS, H2O/DMSO; (d) Ir(ppy)3-β-Ala-COOH, DCC, NHS, H2O/DMSO. The amino acid sequence for cleavage is highlighted in red and comprised of either l-amino acid or d-amino acids. All other amino acids used to generate these structures were d-amino acids.
Bottom Line: Ir(ppy)3 and Cy5 were used because in close proximity the emission intensities of both luminophores were quenched and the influence of Cy5 shortens the Ir(ppy)3 luminescence lifetime from 98 ns to 30 ns.Upon cleavage in vitro, both effects are undone, yielding an increase in Ir(ppy)3 and Cy5 luminescence and a restoration of Ir(ppy)3 luminescence lifetime to 94 ns.As a reference for the luminescence activation, a similar imaging agent with the more common Cy3-Cy5 fluorophore pair was used.

View Article: PubMed Central - PubMed

Affiliation: Interventional Molecular Imaging Laboratory, Department of Radiology, Leiden University Medical Center, Leiden 2300RC, The Netherlands. m.t.m.rood@lumc.nl.

ABSTRACT
Optical (molecular) imaging can benefit from a combination of the high signal-to-background ratio of activatable fluorescence imaging with the high specificity of luminescence lifetime imaging. To allow for this combination, both imaging techniques were integrated in a single imaging agent, a so-called activatable lifetime imaging agent. Important in the design of this imaging agent is the use of two luminophores that are tethered by a specific peptide with a hairpin-motive that ensured close proximity of the two while also having a specific amino acid sequence available for enzymatic cleavage by tumor-related MMP-2/9. Ir(ppy)3 and Cy5 were used because in close proximity the emission intensities of both luminophores were quenched and the influence of Cy5 shortens the Ir(ppy)3 luminescence lifetime from 98 ns to 30 ns. Upon cleavage in vitro, both effects are undone, yielding an increase in Ir(ppy)3 and Cy5 luminescence and a restoration of Ir(ppy)3 luminescence lifetime to 94 ns. As a reference for the luminescence activation, a similar imaging agent with the more common Cy3-Cy5 fluorophore pair was used. Our findings underline that the combination of enzymatic signal activation with lifetime imaging is possible and that it provides a promising method in the design of future disease specific imaging agents.

Show MeSH