Linear optical methods of determining the chirality of organic and inorganic materials have relied on weak chiral optical (chiroptical) effects. Nonlinear chiroptical characterization holds the potential of much greater sensitivity and smaller interaction volumes. However, suitable materials on which to perform measurements have been lacking for decades. Here, we present the first nonlinear chiroptical characterization of crystallographic chirality in gold helicoids (≈150 nm size) and core/shell helicoids with the newly discovered hyper-Rayleigh scattering optical activity (HRS OA) technique. The observed chiroptical signal is, on average, originating from between ≈0.05 and ≈0.13 helicoids, i.e., less than a single nanoparticle. The measured HRS OA ellipticities reach ≈3°, for a concentration ≈10 9 times smaller than that of chiral molecules with similar nonlinear chiroptical response. These huge values indicate that the helicoids are excellent candidates for future nonlinear chiroptical materials and applications.

ombinatorial nanochemistry allows tens to millions of mixtures to be produced in a single process 1,2 , generating large chemical libraries [3][4][5][6][7] and making implementation of artificial intelligence algorithms possible. Following the rapid development of chiral nanostructures [8][9][10][11][12][13] , such synthetic and analytical platforms can be applied to the high-throughput assessment of enzyme mimics, contrast agents, antibiotic agents, drug delivery vehicles, as well as other applications of these bioinspired materials. These analyses should be carried out in microplates of 1,536, 3,456 or 9,600 wells, with sample volumes as small as, and smaller than, 1 µl (ref.

The design and synthesis of water soluble, amino-acid-functionalised naphthalenediimides (NDIs) as potential ligands of native G-quadruplexes is reported. The NDIs were tested on a panel of oncogene promoters, on the human telomeric sequence h-telo, and on double-stranded DNA. Out of the ligands tested, NDI 3 (N -Boc-l-lysine NDI) exhibited a highly discriminating nature by only stabilising the oncogene promoter c-kit2, which is up-regulated up to 80 % in ovarian, gastrointestinal, and breast malignancies.

In 3D isotropic liquids, optical third‐harmonic generation is forbidden, with circularly polarized light (CPL). Yet the associated nonlinear susceptibility directly influences the optical properties at the fundamental frequency by intensity dependence (Kerr effect). Here, the hidden third‐harmonic optical properties upon CPL illumination are revealed by demonstrating a new effect, in hyper‐Rayleigh scattering. This effect is succinctly enunciated: the intensity of light scattered at the third‐harmonic frequency of the CPL incident light depends on the chirality of the scatterers. It is referred to as third‐harmonic (hyper) Rayleigh scattering optical activity (THRS OA) and was observed from Ag nanohelices randomly dispersed in water. The first analytical theory model for the new effect in nanohelices is also provided, highlighting the role of localized transition dipoles along the helical length. THRS OA is remarkably user‐friendly. It offers access to intricate optical properties (hyperpolarizabilities) that have so far been more easily accessible by computation and that are essential for the understanding of light−matter interactions. The new effect could find applications in hyper‐sensitive characterization of the chirality in molecules and in nanostructures; this chirality plays a fundamental role in the function of bio/nano‐machinery, with promising applications in next generation technologies.

Uncovering the role of global protein dynamics in enzyme turnover is needed to fully understand enzyme catalysis. Recently, we have demonstrated that the heat capacity of catalysis, Δ C P ‡ , can reveal links between the protein free energy landscape, global protein dynamics, and enzyme turnover, suggesting that subtle changes in molecular interactions at the active site can affect long-range protein dynamics and link to enzyme temperature activity. Here, we use a model promiscuous enzyme (glucose dehydrogenase from Sulfolobus solfataricus ) to chemically map how individual substrate interactions affect the temperature dependence of enzyme activity and the network of motions throughout the protein. Utilizing a combination of kinetics, red edge excitation shift (REES) spectroscopy, and computational simulation, we explore the complex relationship between enzyme–substrate interactions and the global dynamics of the protein. We find that changes in Δ C P ‡ and protein dynamics can be mapped to specific substrate–enzyme interactions. Our study reveals how subtle changes in substrate binding affect global changes in motion and flexibility extending throughout the protein.