High levels of molecular orientation of surface azo chromophores can be optically induced even in a wet biological environment

Abstract

We have developed polyelectrolyte multilayer bio-films containing azobenzene chromophores that enhance reversible photo-orientation upon irradiation with linearly polarized light, to effect surface photoswitching of adjacent biological systems. When conditions of film preparation and irradiation were optimized, we could observe the highest measured birefringence to date in amorphous systems (Dn > 0.2). This birefringence change to probe orientation was also for the first time measured and determined to be stable completely underwater, permitting optimization for in situ applications immersed in biological conditions.