PHOTOCHROMIC POLYPEPTIDES

The article provides a detailed overview of current research in the he ld of photochromic polypeptides. Polypeptides are special polymers bec ause of their ability to exist in well-defined ordered structures, suc h as alpha-helix and beta-structures. When photochromic units, such as azobenzene and spiropyran, are introduced into the side chains of the se macromolecules, photochromic polypeptides may respond to light givi ng photoinduced reversible structural changes, including random coil/a lpha-helix transitions, helix-sense reversals, photostimulated aggrega tion/disaggregation processes, and photomechanical effects. Moreover, experimental findings provide evidence that the photoinduced structura l changes occur as cooperative transitions, therefore photochromic pol ypeptides actually work as amplifiers and transducers of the primary p hotochemical event occurring in the side chains. These fascinating pro perties suggest that photochromic polypeptides may have many future op portunities as suitable materials for application in photo-optical tec hnology, and for designing sensors and devices that can be photomodula ted.