We investigate label-free measurement of molecular distribution by super-resolved Raman microscopy using surface plasmon (SP) localization. Localized SP was formed with plasmonic nanopost arrays (PNAs) for measurement of the molecular distribution in HeLa cells. Compared with conventional Raman microscopy on gold thin films, PNAs induce a localized near-field, which allows for the enhancement of the peak signal-to-noise ratio by as much as 4.5 dB in the Raman shifts. Super-resolved distributions of aromatic amino acids and lipids (C-C stretching and C-H2 twist mode) as targets in HeLa cells were obtained after image reconstruction. Results show almost 4-fold improvement on average in the lateral precision over conventional diffraction-limited Raman microscopy images. Combined with axial imaging in an evanescent field, the results suggest an improvement in optical resolution due to superlocalized light volume by more than an order of magnitude over that of conventional diffraction-limited Raman microscopy.
Bibliographical noteFunding Information:
This work was supported by National Research Foundation grants funded by the Korean Government (2019R1A4A1025958, 2019K2A9A2A08000198, and 2019R1A6A3A01096804) and partly sponsored by the Ministry of Trade, Industry and Energy (P048000064). We acknowledge Woo Joong Rhee and Prof. Jeon-Soo Shin at the Department of Microbiology, School of Medicine, Yonsei University for preparing HeLa cells for SEM on PNAs.
© 2020 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanical Engineering