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

A near-infrared photoacoustic probe was used to image bone through active and bioorthogonal pretargeting strategies that utilized coupling between a tetrazine-derived cyanine dye and a -cyclooctene-modified bisphosphonate. hydroxyapatite binding of the probe active and pretargeting strategies showed comparable increases in percent binding 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.

Tetrazine-Derived Near-Infrared Dye as a Facile Reagent for Developing Targeted Photoacoustic Imaging Agents.

A new photoacoustic (PA) dye was developed as a simple-to-use reagent for creating targeted PA imaging agents. The lead molecule was prepared via an efficient two-step synthesis from an inexpensive commercially available starting material. With the dye's innate albumin-binding properties, the resulting tetrazine-derived dye is capable of localizing to tumor and exhibits a biological half-life of a few hours, allowing for an optimized distribution profile.