Catching Bubbles: Targeting Ultrasound Microbubbles Using Bioorthogonal Inverse‐Electron‐Demand Diels–Alder Reactions

Catching bubbles: Tetrazine‐functionalized microbubbles were prepared for use as ultrasound contrast agents, and shown to selectively localize on cells labeled with a TCO‐derivatized antibody against VEGFR2. This capture approach based on labeling and bioorthogonal chemistry was validated in a flow‐chamber assay and in vivo through ultrasound imaging of VEGFR2‐positive and VEGFR2‐negative murine tumor models. TCO=trans‐cyclooctene.