Azobenzene-Modified Temperature-Responsive Short Elastin-like Peptides for Photo-Controlled Phase Transition

Elastin-like peptides (ELPs) have attracted attention as temperature-responsive biomaterials that can be used as drug carriers. In this study, temperature- and photoresponsive self-assembling peptide analogues were developed by conjugating short ELPs (total 20 amino acid residues) and azobenzene derivatives. The synthesized ELP-azobenzene conjugates exhibited reversible spectral changes upon UV or visible-light irradiation and temperature-responsive phase separation in aqueous solutions. The aggregation ability of the trans-isomers of the ELP-azobenzene conjugates was stronger than that of the cis-isomers. This phenomenon was attributed to the change in the hydrophilicity of the azobenzene moiety associated with photoisomerization from the trans- to the cis-isomer. In addition, aggregates of the ELP-azobenzene conjugate could be controlled by light irradiation. Therefore, this study provides a methodology for photo- and temperature-responsive ELP analogues with low molecular weights that can be easily synthesized by simple chemical reactions and are potential candidates for drug carriers that enable precise control of drug release.

elastin-like peptide; phase separation; photoresponsive peptide; repetitive sequence; temperature-responsive peptide.