A metallo-biopolymer conjugate of elastin-like polypeptide: photoluminescence enhancement in the coacervate microenvironment.

An optically active metallo-polymer assembly is demonstrated via conjugation of a genetically engineered elastin-like polypeptide (ELP) and a ruthenium(II) polypyridyl complex. By taking advantage of the phase transition of ELPs in water, photophysical properties of the resultant conjugate are investigated for both phases, below and above the critical transition temperature. Upon coacervation, the luminescence of the metallo-ELP is greatly enhanced as a consequence of local effects on the metal-ligand luminophore. These findings open a possibility to harness the temperature control of stimuli-responsive properties of biopolymers.