Beschreibung:
<jats:p>Shear stress measurements are routinely calculated using local fluid velocity gradients and estimated static viscosity values. However, since blood viscosity is dependent on local hematocrit and is affected by non‐Newtonian shear‐thinning, a methodology allowing concurrent blood velocity and viscosity measurement should improve intracardiac shear mapping accuracy. Our objective was to develop such a methodology using viscosity‐sensitive fluorescent molecular rotors coupled to inert microspheres and validate the approach in a zebrafish model. Microinjection parameters have been optimized for effective delivery of rotors into the zebrafish vascular bed. Age‐dependent injection targets have been identified to facilitate reproducible bolus delivery. Finally, FCVJ reflect local hemodynamic profiles demonstrating a functionality consistent with their <jats:italic>in vitro</jats:italic> performance. Taken together, our data indicate that fluorescent molecular rotors provide the spatial and temporal resolution required for use in planar and volumetric digital defocusing particle image velocimetry (DDPIV) technology to facilitate real‐time 3‐dimensional <jats:italic>in vivo</jats:italic> shear mapping. (This work funded by AHA 10IRG4020025.)</jats:p>