Choose your label wisely: water-soluble fluorophores often interact with lipid bilayers.

Water-soluble organic fluorophores are widely used as labels in biological systems. However, in many cases these fluorophores can interact strongly with lipid bilayers, influencing the interaction of the target with the bilayer and/or leading to misleading fluorescent signals. Here, we quantify the interaction of 32 common water-soluble dyes with model lipid bilayers to serve as an additional criterion when selecting a dye label.