Cholera toxin B subunit is used for tract-tracing in neurological research, targeting GM1 ganglioside binding and retrograde transport. CF® dyes are Biotium's line of next-generation fluorescent dyes with advantages in brightness, photostability, and conjugate specificity compared to other fluorescent dyes. Far-red/near-IR fluorescent CF®680R dye has excitation/emission at 680/701 nm.