Chiral Nanostructures and Optical Activity

Chiral nanostructures are nanoscale materials whose three-dimensional architectures lack mirror symmetry, endowing them with distinct left- or right-handed geometries. When exposed to polarised light, these assemblies interact differently with left- and right-circularly polarised electromagnetic fields, giving rise to optical activity manifest as circular dichroism, optical rotatory dispersion or more exotic phenomena such as hyper-Raman optical activity. Advances in synthetic control—from seed-mediated growth of twisted metal nanorods to bioinspired assembly of inorganic frameworks—have allowed precise tuning of chiral morphology and the resultant optical response across the ultraviolet, visible and infrared regimes. These developments underpin applications in enantioselective catalysis, chiroptical sensing, photonic devices and biomedical imaging. Moreover, the ability to amplify and transfer chirality from molecular templates to extended nanostructures offers new routes to functional materials that mimic biological homochirality. Ongoing research aims to deepen mechanistic insight into field-driven chirality conferral, improve characterisation methods and harness plasmonic enhancement to boost sensitivity and selectivity in real-world applications.

Research from Nature Portfolio

Recent studies have reported the experimental observation of hyper-Raman optical activity in field-driven chiral systems. By designing gold nanohelices coupled to achiral dye molecules in a doubly resonant configuration, researchers have directly measured the elusive hyper-Raman chiroptical signal predicted decades ago. This work provides a theoretical framework that extends conventional Raman and surface-enhanced scattering formalisms to include chirality conferral via electromagnetic fields, opening avenues for new spectroscopic tools and nanoscale chirality manipulation. In parallel, bioinspired approaches have been demonstrated for the synthesis of inorganic chiral nanomaterials that emulate natural motifs. Studies on templated mineralisation and ligand-directed assembly have elucidated design principles for transferring molecular handedness into robust, inorganic architectures with strong circular dichroism and plasmonic resonances. These findings bridge fundamental understanding of biomolecular chirality transfer with practical schemes for scalable fabrication of chiral photonic platforms.

Chiral Nanostructures and Optical Activity publication trend

The graph below shows the total number of articles in chiral nanostructures and optical activity across all publications each year (not limited to Nature Index journals).

Technical terms

Chirality: A property of a structure that is not superimposable on its mirror image, often described as left- or right-handedness.

Optical activity: The capacity of a chiral medium to rotate the plane of polarised light or produce differential absorption of circular polarisations.

Circular dichroism (CD): An absorption difference between left- and right-circularly polarised light, used to characterise chiral materials.

Plasmonic chirality: Chiroptical phenomena arising from collective electron oscillations (plasmons) in metal nanostructures with chiral geometries.

Hyper-Raman optical activity: A nonlinear chiroptical effect in which vibrational modes exhibit chirality-dependent scattering in the presence of intense fields.

References

1. Circularly Polarized Light-Enabled Chiral Nanomaterials: From Fabrication to Application. Nano-Micro Letters (2023).
2. Chiral supramolecular nanomaterials: From chirality transfer and amplification to regulation and applications. Interdisciplinary Materials (2023).
3. Chirality conferral enables the observation of hyper-Raman optical activity. Nature Photonics (2024).
4. Bioinspired chiral inorganic nanomaterials. Nature Reviews Bioengineering (2023).
5. Chiral acidic amino acids induce chiral hierarchical structure in calcium carbonate. Nature Communications (2017).
6. Chiral Seeded Growth of Gold Nanorods Into Fourfold Twisted Nanoparticles with Plasmonic Optical Activity. Advanced Materials (2022).