Photo-Controllable Förster Resonance Energy Transfer Based on Dynamic Chiral Self-Assembly of Sequence-Defined Amphiphilic Alternating Azopeptoids.

Endowing biomimetic sequence-controlled polymers with chiral functionality to construct stimuli-responsive chiral materials offers a promising approach for innovative chiroptical switch, but it remains challenging. Herein, it is reported that the self-assembly of sequence-defined chiral amphiphilic alternating azopeptoids to generate photo-responsive and ultrathin bilayer peptoidosomes with a vesicular thickness of ≈1.50 nm and a diameter of around ≈290 nm. The photoisomerization of azobenzene moiety facilitates a reversible structural transformation from isotropic peptoidosomes to anisotropic 1D helical nanoribbons (≈80 nm width) under the alternating irradiation with UV and visible lights, consequently leading to the chirality expression and transfer from chiral asymmetric center to achiral azobenzene units. As a biomimetic model with deformation-induced energy transfer, a non-invasive azobenzene-based Förster resonance energy transfer system is unprecedentedly constructed via the introduction of a fluorescent donor of pyrene derivatives and sequentially photo-regulated the donor/acceptor ratio, displaying a reversible gradient fluorescent color variation from blue to yellow (a broad Stokes shift of ≈200 nm) and a high-efficient energy transfer efficiency of 97.2%. The photo-controllable photoluminescence phenomenon endows these chiral aggregates with a proof-of-concept application on multi-colored information encryption. This work provides a prospective strategy to fabricate stimuli-responsive chiral biomimetic materials with a potential on the light-controllable switches.