Near-infrared fluorescence imaging of mouse myocardial microvascular endothelium using Cy5.5-lectin conjugate

Cy5.5-lectin, a non-toxic conjugate, combines the benefits of near-infrared (NIR) imaging, such as significant reduction of background fluorescence and increased tissue depth penetration, with its affinity for vascular endothelial cells. When compared to endothelial staining methods using FITC-lectin and ICAM2 antibodies, Cy5.5-lectin was confirmed to specifically bind endothelial cells and produce a fluorescence signal both in real-time and post-infusion. Ex-vivo experiments with isolated hearts demonstrated that binding was limited to perfused areas of the myocardium. With mouse in-vivo tail-vein injections, other organs such as the liver, spleen, and kidney were also stained and yielded similar quality images of the heart.