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Enantioselective sensing by collective circular dichroism
Ryeong Myeong Kim1, Ji-Hyeok Huh2, SeokJae Yoo3
1Department of Materials Science and Engineering, Seoul National University, Seoul, Republic of Korea.
Nature
|December 14, 2022
Summary
Detecting molecular chirality at low concentrations is difficult. This study introduces collective resonances from chiral gold nanoparticles, offering a uniform chiral field for improved enantioselective sensing.
Area of Science:
- Nanophotonics
- Spectroscopy
- Chiral sensing
Background:
- Quantitative determination of molecular chirality at low concentrations is challenging due to scale mismatch with light.
- Conventional nanophotonic approaches rely on localized resonances, which are sensitive to molecular orientation and concentration.
- Existing methods struggle with spatial variations in chiral hotspots, leading to potential errors in enantioselective sensing.
Purpose of the Study:
- To identify enantioselective characteristics of collective resonances (CRs) for improved chiral sensing.
- To overcome limitations of conventional nanophotonic approaches in detecting molecular chirality.
- To develop a method for sensitive and reliable enantioselective sensing.
Main Methods:
- Assembling 2D crystals of isotropic, 432-symmetric chiral gold nanoparticles (helicoids).
- Investigating collective resonances (CRs) arising from these assembled structures.
- Analyzing the chiral near-field properties and their interaction with analytes.
Main Results:
- Collective resonances (CRs) exhibit a strong and uniform chiral near field over a large volume.
- The chiral near field is generated by collectively spinning, optically induced dipoles.
- Analyte handedness causes opposite shifts in CRs, maximizing modulation of collective circular dichroism (CD).
Conclusions:
- Collective resonances from 2D chiral nanoparticle crystals offer a robust platform for enantioselective sensing.
- The uniform chiral near field minimizes errors associated with molecular orientation and concentration.
- This approach significantly enhances the modulation of collective circular dichroism for sensitive chiral detection.
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