IR820 is a non-invasive near-infrared (NIR) fluorescence imaging dye that belongs to the family of the heptamethine dyes and has a rigid cyclohexenyl ring, increasing molecular stability and photostability. IR820 could be used as both an imaging dye and a hyperthermia agent.1
IR820 has a little absorption in the visible range thus exhibit low autofluorescence, tissue absorbance, and scatter at NIR wavelengths (700-900 nm).
Dibenzocyclooctyne derivative of the IR820 dye offer the opportunity to develop optimal conjugates. Dibenzocyclooctyne reactive groups provide an efficient and convenient way to selectively link IR820 dyes to azides on various substrates (Antibodies, peptides, proteins, nucleic-acid, fatty acids, small molecule drug…). Dibenzocyclooctyne are very reactive against azides. The conjugation is based on Huisgen cycloaddition of an azide to strained cyclic alkyne (dibenzocyclooctyne). Unlike traditional azide/alkine reaction it does not require Cu(I) catalyst. Dibenzocyclooctyne are non-endogeneous functional groups, thus they are not naturally present on targeting molecules (biomolecules). On the other hand, azides derivatives of biomolecules and small molecules are widely in research and are commercially available from numerous sources. The reaction proceeds under aqueous conditions at physiological temperatures and pressures. The dibenzocyclooctyne/azide combination is thus a bioorthogonal reaction.