A New Class of Stable Heptamethine Cyanine Fluorophores and Biomedical Applications Thereof

Heptamethine cyanines are among the most widely used near-IR fluorophores. The near-IR range (between about 650 nm and 900 nm) is very useful for imaging applications due to the absence of background autofluorescence. Despite extensive use, many of these fluorophores suffer from chemical instability. Specifically, most of the current and commonly used fluorophores undergo a phenoxy to thiol exchange reaction in the presence of primary thiols. This exchange reaction is problematic during conjugation reactions of cysteine containing macromolecules. These exchange reactions are further complication by the fact that they occur intracellularly.

Researchers at the National Cancer Institute (NCI) have developed an improved class of fluorophore dyes comprised of heptamethine cyanines. These improved dyes present a novel and much needed tool for imaging applications in the near-IR range. Specifically, these dyes display greater resistance to thiol nucleophiles, and are therefore, more robust while maintaining their useful optical properties. The preparation of these dyes is more facile with higher yields than preparative routes for other competing fluorphore dyes. The inventors have taken advantage of these useful properties to apply the dyes to various in vivo imaging applications.
The researchers at the National Cancer Institute (NCI) continue to develop these dyes as targetable agents for optical-guided surgical interventions.

 This technology is available for licensing and collaboration opportunities for joint development are available to qualified entities.