Fluorescent labels having near-infrared (NIR) emission wavelengths have the ability to penetrate tissue deeper than other emission wavelengths, providing enormous potential for non-invasive imaging applications. However, advancement of optical imaging (particularly NIR imaging) is hindered by the limitation of narrow Stokes shift of most infrared dyes currently available in the market. Vanderbilt researchers have developed a novel NIR dye (4-Sulfonir) for multichannel imaging that enables in vivo imaging of multiple targets due to its large Stokes shift. 4-Sulfonir with its unique large Stokes shift (~150 nm) and wide excitation spectrum could be used in parallel with other NIR dyes for imaging two molecular events simultaneously in one target.
