Optical transition induced by molecular transformation in peptide nanostructures

In this letter we present a variation in the optical properties of bio-organic peptide nanostructures, which are induced by molecular transformation. The self-assembled tubular structures are formed from short aromatic di-peptides. Upon thermal induction, the structure changes its molecular conformation, and the linear di-peptide closes into a cyclic peptide. This irreversible transition changes the molecular packing at the nanoscale, which results in reconstruction of the native quantum dot-like packing to quantum well-like packing and the generation of blue luminescence. We further show that the same cyclic peptide can exhibit different photoluminescence properties according to the formed structure. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3691254]