ICG-PEG12-OSu

Indocyanine green (ICG) is a cyanine dye used in medical diagnostics. It is used for determining cardiac output, hepatic function, and liver blood flow, and for ophthalmic angiography. It has a peak spectral absorption close to 800 nm. These infrared frequencies penetrate retinal layers, allowing ICG angiography to image deeper patterns of circulation than fluorescein angiography. Conventional activated ICG dye, ICG-Sulfo-OSu, has been used for preparing ICG-antibody conjugates utilized in in vivo imaging research as antibody conjugates. However, the ICG hydrophobicity often causes some unspecific bindings and antibody aggregation. The PEG12-modified ICG dyes are the most water-soluble ICG dyes. Their antibody conjugates shows better water solubility and significantly reducing unspecific binding.