The emission maximum of IRDye 800CW infrared dye is at 789 nm in aqueous solution.
Since the emission of IRDye® 800CW infrared dye is separated by more than 100 nm from most commonly used dyes (Cy5, for example, emits at 670 nm), there is no risk of spectral overlap or cross-talk between channels.
Very low autofluorescence at 800 nm: NIH 3T3 cells were fixed in 0.2% glutaraldehyde. These unstained cells were viewed using standard blue, green, and red filters, plus an IRDye 800 infrared dye filter set from Chroma Technology Corp. Glutaraldehyde fixation caused strong autofluorescence in the visible fluorescence channels (blue, green, and red). However, no autofluorescent background could be seen in the IRDye 800 infrared dye channel, even with a very long exposure (signal would be shown as red in false color).
Image captured with Leica DM RXA epifluorescent deconvolution microscope, outfitted as follows: xenon light source, IRDye 800 filter set from Chroma Technology (EX: HQ740/35x, DC: 770DCXR, EM: HQ780LP), and Cooke Sensicam CCD camera without extended spectral range. Image courtesy of Mark Winey and Harold Fisk, University of Colorado at Boulder.