Imaging plasma membrane phase behaviour in live cells using a thiophene-based molecular rotorThis paper is dedicated to Prof. Tomás Torres on the occasion of his 65th birthday.Electronic supplementary information (ESI) available: Materials and methods; additional spectroscopic and computational data. See DOI: 10.1039/c6cc05954f

Molecular rotors have emerged as versatile probes of microscopic viscosity in lipid bilayers, although it has proved difficult to find probes that stain both phases equally in phase-separated bilayers. Here, we investigate the use of a membrane-targeting viscosity-sensitive fluorophore based on a thiophene moiety with equal affinity for ordered and disordered lipid domains to probe ordering and viscosity within artificial lipid bilayers and live cell plasma membranes. A thiophene-based molecular rotor was used to probe ordering and viscosity within artificial lipid bilayers and live cell plasma membranes.