Fluorescent conjuates of α -Bungarotoxin bind to the nicotinic acetylcholine receptor with high affinity, and thus can be used to image the distribution of the receptor at the neuromuscular junctions. CF® dyes are Biotium's line of next-generation fluorescent dyes with advantages in brightness, photostability, and conjugate specificity compared to other fluorescent dyes. Blue fluorescent CF®405S has excitation/emission at 404/431 nm.