Session: Nanoscience:

Plasmonic intra-nanogap particles create a strong electromagnetic field in the nanogap region due to plasmonic coupling between core and shell, which can be beneficial for optical signal enhancements such as surface-enhanced Raman scattering (SERS). The strategy for synthesizing plasmonic intra-nanogap particles with well-defined nanogaps, especially around the 1 nm region, in high yields as well as positioning various Raman dyes in the gap is crucial to generate strong and multiplexable SERS signals. However, the reproducible synthesis of the uniform intra-nanogap that can accommodate various Raman dyes with a simple and facile approach is still challenging. Here, we develop a synthetic strategy to form cyclodextrin-based intra-nanogap particle (CDIP) with a well-defined ~1 nm gap by forming a gold shell on the β-cyclodextrin-modified Au core. The cyclodextrin molecules on the core facilitate the formation of the uniform nanogap as well as the accommodation of various Raman dyes through inclusion complexes, giving rise to strong and multiplexable SERS signals. The average SERS enhancement factor (EF) is 3.0×10⁹ with a narrow distribution within around 1 order of magnitude ranging from 9.5×10⁸ to 9.5×10⁹ for ~ 95% of the measured CDIPs. Remarkably, 10 different Raman dyes can be loaded within the nanogap of CIPs, and 6 different Raman dye-loaded CIPs with little spectral overlaps were distinctly detected for cancer cell imaging applications with a single excitation source. Our strategy is a simple and facile synthetic method to form a uniform and well-defined plasmonic intra-nanogap particle with strong SERS signals and the capability of various Raman dyes accommodation through cyclodextrin molecules.

Synthetic strategy to prepare cyclodextrin-based plasmonic intra-nanogap particles in a high yield and their surface-enhanced Raman scattering-based multiplexable cancer cell imaging applications.

Synthetic strategy to prepare cyclodextrin-based plasmonic intra-nanogap particles in a high yield and their surface-enhanced Raman scattering-based multiplexable cancer cell imaging applications.

MinJi Ha

Seoul National University

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