Mirror-Image Nanoparticles Patterned On Peptides

Researchers have shown that chirality, which is typically observed in organic molecules, can be extended to three-dimensional metallic nanostructures.

AsianScientist (May 4, 2018) – Scientists in South Korea have successfully created optically active, chiral gold nanoparticles using amino acids and peptides. Their synthesis method has been published in Nature.

Many chemicals significant to life have mirror-image twins (left-handed and right-handed structures), a characteristic that is called chirality. In this study, researchers at Seoul National University (SNU), Pohang University of Science and Technology (POSTECH) and LG Display showed how chirality can be extended from nature to three-dimensional metallic nanostructures.

The researchers observed that the chirality of peptides can be directly transferred to gold nanoparticles. The resulting chiral nanoparticles can be further tuned by varying the sequence of the peptide used.

In the nanoparticles, chiral elements are arranged on cube-like structures with a side length of only about 100 nm. They can be easily dispersed in solutions and deposited on the substrates while maintaining high chiro-optical activities.

The chiral gold nanoparticles with different handedness interacted differently with circularly polarized visible light, displaying extensive color modulation. As a result, color change is possible by controlling the polarization of light. This property has potential applications in future displays, the researchers said.

“Based on our understanding of the interface between peptides and inorganic materials, we have built a new platform technology to control the crystallographic asymmetry,” explained study leader Professor Nam Ki Tae of SNU. “This finding can make a direct and immediate impact on optical devices and could be further applied for the development of enantioselective bioinspired catalysts in the near future.”

“The potential applications [of this technology] include active color displays, holography, chirality sensors and all-angle negative refractive index materials,” said Professor Rho Junsuk at POSTECH, who is the co-corresponding author of the study.

The article can be found at: Lee et al. (2018) Amino-acid- and Peptide-directed Synthesis of Chiral Plasmonic Gold Nanoparticles.


Source: Seoul National University.
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