Kawawaki Tokuhisa, Shinjo Naoaki, Tatsuma Tetsu
Institute of Industrial Science, The University of Tokyo.
Anal Sci. 2016;32(3):271-4. doi: 10.2116/analsci.32.271.
Localized surface plasmon resonance (LSPR) sensors based on plasmonic nanoparticles are sensitive to changes in local refractive index, so that they are used for affinity-based chemical sensing and biosensing. Conventional LSPR sensors are generally based on transmission of light through the sensor and a sample solution, which could be colored or turbid. In this study, we develop backward-scattering-based LSPR sensors that can be applied to colored or turbid sample solutions. Au nanospheres (100 nm diameter) and Au nanoshells (25 nm thick) with SiO2 cores (80 nm diameter) are used as plasmonic nanoparticles and immobilized on a glass substrate. The refractive index sensitivities of the Au nanospheres and nanoshells are 128 and 278 nm RIU(-1), respectively, which are in good agreement with simulated values and the values for conventional transmission-based LSPR sensors. The Au nanoshells require a lower amount of Au for the same scattering intensity in comparison with the Au nanospheres. The backward-scattering-based LSPR sensing is possible with the Au nanospheres and nanoshells even in coffee as a colored and turbid sample.
基于等离子体纳米粒子的局域表面等离子体共振（LSPR）传感器对局部折射率的变化敏感，因此可用于基于亲和力的化学传感和生物传感。传统的LSPR传感器通常基于光透过传感器和样品溶液进行传输，而样品溶液可能有颜色或浑浊。在本研究中，我们开发了基于背向散射的LSPR传感器，其可应用于有颜色或浑浊的样品溶液。直径为100 nm的金纳米球和具有80 nm直径SiO2核、壳层厚度为25 nm的金纳米壳被用作等离子体纳米粒子，并固定在玻璃基板上。金纳米球和金纳米壳的折射率灵敏度分别为128和278 nm RIU(-1)，这与模拟值以及传统基于透射的LSPR传感器的值高度吻合。与金纳米球相比，对于相同的散射强度，金纳米壳所需的金量更少。即使在作为有颜色和浑浊样品的咖啡中，基于金纳米球和金纳米壳的背向散射LSPR传感也是可行的。
