Harnessing cyanine reactivity to prepare novel fluorophores for in vivo imaging applications

Cyanines are the most commonly used fluorescent probes for in vivo FGS applications, despite challenging properties for in vivo use. To address this, our research focuses on developing new synthetic methods that modify the key polymethine chromophore unit. We have developed probes with rapid and exclusive renal or hepatobiliary clearance for abdominal surgery applications. Additionally, we have extensively examined the role of probe chemistry on tumor targeting of monoclonal antibody (mAb) conjugates. This research has led to the discovery of FNIR-Tag, a molecule with excellent characteristics for in vivo mAb-targeted imaging, including improved labeling properties, reduced hepatic clearance, and enhanced in vivo tumor uptake and signal. Collaborative studies have shown that FNIR-Tag also enhances the in vivo properties of various other targeting agents, including virus-like particles, nanobodies, and peptides. An ongoing challenge in the field is the development of probes that target intracellular structures. To address this, we've recently developed probes capable of reversible cyclization chemistry, enabling efficient intracellular labeling.