Fig. 13

Au thiolate hierarchically organized particles (HOPs) with Cys ligands. a–c SEM images of Au–l-Cys and Au–d-Cys coccolith-like particles (CLIPs) (a and b) and Au–DL-Cys kayak particles (c). d–f SEM images and corresponding schematic illustrations of segments of Au–l-Cys (d), Au–d-Cys (e), and Au–dl-Cys (f). g, h CPP (g) and CD (h) spectra of Au–l-Cys CLIPs (blue), Au–d-Cys CLIPs (red), and Au–dl-Cys kayak particles (black). Inset in g Photos of Au–l-Cys, Au–d-Cys, and Au–dl-Cys dispersions under daylight (top) and UV light (bottom) illumination. i, j circularly polarized emission (i) and CD (j) spectra of Au–l-Cys (blue) and Au–d-Cys (red) after sonication. Inset in j The same spectra for the 500- to 1350-nm spectral window to confirm the absence of the CD peaks associated with differential scattering of assembled CLIPs. The helicity of the nanoribbon stacks of Au–l-Cys is left-handed, and therefore the light scattered by Au–l-Cys has left-handed polarization. After disassembly of the stacks into single right-handed nanoribbons, the light passing through these dispersions acquires right-handed circular polarization. Reproduced with permission from [12].