Dynamic Tunable Chiral Plasmonic Properties via Self-Assembly on Helical Threads

Tailorable chiral plasmonic nanostructures have attracted great interest due to their potential applications in photonics and sensing. However, there are limited straightforward fabrication routes to modulate the morphology of chiral materials with an external stimulus. Here, a helical assembly of gold nanospheres (AuNSs) is successfully obtained via self-assembly using glycopeptide helical nanofibers as templates based on electrostatic interactions. The assembly morphology can be readily tailored from short debris to single-/double- and multiple helical threads by changing pHs, resulting in well-controlled modulation of circular dichroism (CD) in the visible range. Further, this tunable assembly and corresponding chiroptical properties are fully reversible in the pH range from 6 to 10. The electromagnetic simulation revealed how the structural geometries of AuNS helices changed the electromagnetic field propagation pattern to facilitate corresponding chiral optical properties. This approach is a unique and facilely obtained example of chiral nanomaterials with in situ tailoring morphology and chiral properties through external stimulus, demonstrating a potential application for biosensing. Chiral plasmonic structure based on helical assembled gold nanoparticles is realized through colloidal self-assembly with glycopeptide-based chiral nanofibers as templates via electrostatic interactions. The chiral assembly demonstrates dynamically tunable of morphology and chiroptical performance under external pH stimulus, which is fully reversible.image