Tetrazine-Derived Near-Infrared Dye for Targeted Photoacoustic Imaging of Bone

J Med Chem. 2023 May 11;66(9):6025-6036. doi: 10.1021/acs.jmedchem.2c01685. Epub 2023 Apr 27.

Abstract

A near-infrared photoacoustic probe was used to image bone in vivo through active and bioorthogonal pretargeting strategies that utilized coupling between a tetrazine-derived cyanine dye and a trans-cyclooctene-modified bisphosphonate. In vitro hydroxyapatite binding of the probe via active and pretargeting strategies showed comparable increases in percent binding vs a nontargeted control. Intrafemoral injection of the bisphosphonate-dye conjugate showed retention out to 24 h post-injection, with a 14-fold increase in signal over background, while the nontargeted dye exhibited negligible binding to bone and signal washout by 4 h post-injection. Intravenous injection, using both active and pretargeting strategies, demonstrated bone accumulation as earlier as 4 h post-injection, where the signal was found to be 3.6- and 1.5-fold higher, respectively, than the signal from the nontargeted dye. The described bone-targeted dye enabled in vivo photoacoustic imaging, while the synthetic strategy provides a convenient building block for developing new targeted photoacoustic probes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bone and Bones / diagnostic imaging
  • Diagnostic Imaging
  • Diphosphonates
  • Heterocyclic Compounds*
  • Photoacoustic Techniques*

Substances

  • Heterocyclic Compounds
  • Diphosphonates

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