Peptide-Directed Assembly of Single-Helical Gold Nanoparticle Superstructures Exhibiting Intense Chiroptical Activity

• DOI: 10.1021/jacs.6b07322
• Publication Date: 2016-09-26T15:18:10Z
• Authors: Andrea D. Merg; Jennifer C. Boatz; Abhishek Mandal; Gongpu Zhao; Soumitra Mokashi-...; Chong Liu; Xianting Wang; Peijun Zhang; Patrick C. A. van...; Nathaniel L. Rosi
• Keywords: Polyproline helix

Chiral nanoparticle assemblies are an interesting class of materials whose chiroptical properties make them attractive for a variety applications. Here, C18-(PEPAuM-ox)2 (PEPAuM-ox = AYSSGAPPMoxPPF) is shown to direct the assembly single-helical gold superstructures that exhibit exceptionally strong activity at plasmon frequency with absolute g-factor values up 0.04. Transmission electron microscopy (TEM) and cryogenic tomography (cryo-ET) results indicate single helices have periodic pitch approximately 100 nm consist oblong nanoparticles. The morphology assembled structure studied using TEM, atomic force (AFM), Fourier transform infrared (FTIR) spectroscopy, circular dichroism (CD) X-ray diffraction (XRD), solid-state nuclear magnetic resonance (ssNMR) spectroscopy. TEM AFM reveal assembles into linear amyloid-like 1D helical ribbons having structural parameters correlate those superstructures. FTIR, CD, XRD, ssNMR presence cross-β polyproline II secondary structures. A molecular model presented takes account all experimental observations supports architecture. This provides basis design future programmable structures properties.