Photochromic polypeptides

The article provides a detailed overview of current research in the held of photochromic polypeptides. Polypeptides are special polymers because of their ability to exist in well-defined ordered structures, such as alpha-helix and beta-structures. When photochromic units, such as azobenzene and spiropyran, are introduced into the side chains of these macromolecules, photochromic polypeptides may respond to light giving photoinduced reversible structural changes, including random coil/alpha-helix transitions, helix-sense reversals, photostimulated aggregation/disaggregation processes, and photomechanical effects. Moreover, experimental findings provide evidence that the photoinduced structural changes occur as cooperative transitions, therefore photochromic polypeptides actually work as amplifiers and transducers of the primary photochemical event occurring in the side chains. These fascinating properties suggest that photochromic polypeptides may have many future opportunities as suitable materials for application in photo-optical technology, and for designing sensors and devices that can be photomodulated.