Wenpeng Yan

Chiral Transformation of Cyanine Dye Aggregates Induced by Small Peptides

Three small peptides (K4, K5, and K6) with different length were designed to induce the transformation of the assembled state and the chirality of cyanine dye supramolecule. The absorption and circular dichroism (CD) results indicated that, the peptides tend to induce cyanine dye to H-aggregation, competed with Na(+) in PBS, which would induce dye to J-aggregation. Meanwhile, all three peptides could influence the chirality of both J-aggregates induced by Na(+) and H-aggregates, among which K6 could induce chiral reversion of J-aggregates. Furthermore, molecular modeling and energy calculation results have shown that the peptides with different chain length have different conformations. This might be the reason for cyanine dye to form the different chiral assembly induced by these oligo-peptide templates.

Femtosecond time-resolved excited state dynamics of cyanine encapsulated by β-cyclodextrin

Fluorescence dynamics of a cyanine dye, 3,3′-di(3-sulfopropyl)-thiacyanine triethylaminium salt, encapsulated by β-cyclodextrin was investigated by femtosecond fluorescence time-resolved up-conversion technique. The quickening up of the fluorescence decay was found in comparison with the fluorescence dynamics of the dye in water. This phenomenon may be a good experimental support for the expanded BFO theory with two-dimensional excited potential surface.