Novel heptamethine cyanine dyes with large Stoke's shift for biological applications in the near infrared.

A series of novel functionalized, water-soluble, pH-unsensitive, highly photostable heptamethine cyanine dyes (HCDs) has been synthesized. The aim of the synthesis was to obtain novel effective probes for fluorescence detection in the near infrared. Synthesis and characterization of a special HCD with large Stokes' shift (>100 nm), bioconjugation to IgG and effect of pH upon the new structure are presented.