Plasmonic Enhancement of Chiroptical Property in Enantiomers Using a Helical Array of Magnetoplasmonic Nanoparticles for Ultrasensitive Chiral Recognition
Juyong Gwak, Se Jeong Park, Hwa Young Choi, Ji Hoon Lee, Ji Hoon Lee, Ki‐Jae Jeong, Dongkyu Lee, Van Tan Tran, Kyung‐sun Son, Jaebeom Lee, Jaebeom Lee
Abstract
Recognition of enantiomeric molecules is essential in pharmaceutical and biomedical applications. In this Article, a novel approach is introduced to monitor chiral molecules via a helical magnetic field ( h B ), where chiral-inactive magnetoplasmonic nanoparticles (MagPlas NPs, Ag@Fe 3 O 4 core–shell NPs) are assembled into helical nanochain structures to be chiral-active. An in-house generator of h B -induced chiral NP assembly, that is, a plasmonic chirality enhancer (PCE), is newly fabricated to enhance the circular dichroism (CD) signals from chiral plasmonic interaction of the helical nanochain assembly with circularly polarized light, reaching a limit of detection (LOD) of 10 –10 M, a 1000-fold enhancement as compared to that of conventional CD spectrometry. These enhancements were successfully observed from enantiomeric molecules, oligomers, polymers, and drugs. Computational simulation studies also proved that total chiroptical properties of helical plasmonic chains could be readily changed by modifying the chiral structure of the analytes. The proposed PCE has the potential to be used as an advanced tool for qualitative and quantitative recognition of chiral materials, enabling further application in pharmaceutical and biomedical sensing and imaging.