Abstract: Embodiments of the present invention provide a staining solution and of method of using the staining solution for selectively detecting proteins that contain two or more ?-helical transmembrane domains. The staining solution comprises a lipophilic dyes and at least about a 30% hydrophobic solvent. The dyes of the present are represented by the general formula A-B-E wherein A is a nitrogen heterocycle, B is a bridge moiety and E is an electron pair accepting moiety that comprises either a carbonyl or nitrogen atom. In one embodiment these lipophilic dyes are merocyanine dye, a cyanine dye, a styryl dye or a carbazolylvinyl dye.