Minamikawa Takeo, Sakaguchi Reiko, Harada Yoshinori, Tanioka Hiroki, Inoue Sota, Hase Hideharu, Mori Yasuo, Takamatsu Tetsuro, Yamasaki Yu, Morimoto Yukihiro, Kawasaki Masahiro, Kawasaki Mitsuo
Department of Systems Innovation, Graduate School of Engineering Science, Osaka University, Osaka, 560-8531, Japan.
Division of Interdisciplinary Researches for Medicine and Photonics, Institute of Post-LED Photonics, Tokushima University, Tokushima, 770-8506, Japan.
Light Sci Appl. 2024 Oct 28;13(1):299. doi: 10.1038/s41377-024-01655-3.
We demonstrate long-range enhancement of fluorescence and Raman scattering using a dense random array of Ag nanoislands (AgNIs) coated with column-structured silica (CSS) overlayer of over 100 nm thickness, namely, remote plasmonic-like enhancement (RPE). The CSS layer provides physical and chemical protection, reducing the impact between analyte molecules and metal nanostructures. RPE plates are fabricated with high productivity using sputtering and chemical immersion in gold(I)/halide solution. The RPE plate significantly enhances Raman scattering and fluorescence, even without proximity between analyte molecules and metal nanostructures. The maximum enhancement factors are 10-fold for Raman scattering and 10-fold for fluorescence. RPE is successfully applied to enhance fluorescence biosensing of intracellular signalling dynamics in HeLa cells and Raman histological imaging of oesophagus tissues. Our findings present an interesting deviation from the conventional near-field enhancement theory, as they cannot be readily explained within its framework. However, based on the phenomenological aspects we have demonstrated, the observed enhancement is likely associated with the remote resonant coupling between the localised surface plasmon of AgNIs and the molecular transition dipole of the analyte, facilitated through the CSS structure. Although further investigation is warranted to fully understand the underlying mechanisms, the RPE plate offers practical advantages, such as high productivity and biocompatibility, making it a valuable tool for biosensing and biomolecular analysis in chemistry, biology, and medicine. We anticipate that RPE will advance as a versatile analytical tool for enhanced biosensing using Raman and fluorescence analysis in various biological contexts.
我们展示了使用涂覆有厚度超过100nm的柱状结构二氧化硅（CSS）覆盖层的密集随机排列的银纳米岛（AgNIs）实现荧光和拉曼散射的远程增强，即远程类等离子体增强（RPE）。CSS层提供物理和化学保护，减少分析物分子与金属纳米结构之间的相互作用。通过溅射和在金（I）/卤化物溶液中的化学浸渍，以高生产率制造RPE板。即使分析物分子与金属纳米结构之间没有接近，RPE板也能显著增强拉曼散射和荧光。拉曼散射的最大增强因子为10倍，荧光的最大增强因子为10倍。RPE成功应用于增强HeLa细胞内信号动力学的荧光生物传感和食管组织的拉曼组织成像。我们的发现与传统的近场增强理论存在有趣的偏差，因为在其框架内无法轻易解释这些发现。然而，基于我们所展示的现象学方面，观察到的增强可能与AgNIs的局域表面等离子体与分析物的分子跃迁偶极之间的远程共振耦合有关，这种耦合通过CSS结构得以促进。尽管需要进一步研究以充分理解其潜在机制，但RPE板具有实际优势，如高生产率和生物相容性，使其成为化学、生物学和医学中生物传感和生物分子分析的有价值工具。我们预计RPE将发展成为一种通用的分析工具，用于在各种生物环境中使用拉曼和荧光分析增强生物传感。
