Korea University Joint Research Discovers Method For Measuring The Chirality Of Ultrasensitive Molecules
The joint research group of Professor Park Q-Han and Professor Lee Seung-woo of KU and Professor Nam Ki-tae of Seoul National University discovered a new physical phenomenon in regard to chiral nanoparticle-based light-matter interactions and successfully applied it to biomolecules and the analysis of their chirality.
This study was supported by the Creative Materials Discovery Program financed by the Ministry of Science and ICT to develop novel materials for realizing new properties and functions by utilizing new research methodologies (computational science, etc.). The results of the study were published in Nature (IF 69.504) on December 15, 2022.
All living things in nature have specific interactions with light according to their structures and the materials that constitute them. The research group conducted a study on the circularly polarized light-specific interactions of molecules possessing chirality, which is one type of light-matter interaction according to the structural characteristics of various biomolecules.
The chirality of molecules can be determined by comparing their interactions with two types of circularly polarized light that rotate in opposite directions (left circularly polarized light and right circularly polarized light). However, because the light-matter interactions are not sufficiently large due to the size inconsistency of molecules and light, the analysis requires samples of high concentration, takes a long measurement time, and is thus extremely limited.
The research group discovered a breakthrough in solving this problem from a new physical phenomenon found in the two-dimensional assembly structure of chiral gold nanoparticles. Due to their unique geometric characteristics, the chiral gold nanoparticles have a resonance with the incident circularly polarized light and may be used to efficiently control the circularly polarized light near the nanoparticles.
By introducing chiral molecules to a two-dimensional nanoparticle array, the research team successfully maximized the interactions between incident circularly polarized light and chiral molecules, achieving a chirality sensitivity that exceeds the conventional chirality detection limit. In addition, focusing on the finding that the chiral signal amplification caused by the chiral gold nanoparticle array is present in a region including visible light, the research group successfully provided a naked eye-based chirality detector that enables one to distinguish the chirality of molecules without a particular tool.
Professor Park Q-Han and Professor Lee Seung-woo of KU, the co-corresponding authors of the article, performed an electromagnetic simulation on the optical properties of the lattice of chiral gold nanoparticles, demonstrating their sensitivity to molecular chirality and establishing a novel physical theory. They said, “Our results are greatly encouraging because we were able to open a new way to chiral molecule detection through the creative convergence of biomimetic material science, engineering, and computational nano-optics. Now, we live in a new era where we can figure out the chirality of molecules with our naked eyes.”
The ultrasensitive molecular chirality analysis based on the chiral gold nanoparticle array is applicable to the analysis of various biomolecules, chemicals, and pharmaceuticals. Therefore, the new technology is expected to have significant ripple effects on not only various industries where biomaterial synthesis and analysis are important, such as analytics, diagnostics, and pharmaceutics, but also on basic sciences, such as chemistry, biology, and physics.