Shabaninezhad Masoud, Ramakrishna Guda
Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008, USA.
Department of Chemistry, Western Michigan University, Kalamazoo, Michigan 49008, USA.
J Chem Phys. 2019 Apr 14;150(14):144116. doi: 10.1063/1.5090885.
The change in refractive index around plasmonic nanoparticles upon binding to biomolecules is routinely used in localized surface plasmon resonance (LSPR)-based biosensors and in biosensing platforms. In this study, the plasmon sensitivity of hollow gold (Au) nanoshells is studied using theoretical modeling where the influence of shape, size, shell thickness, and aspect ratio is addressed. Different shapes of hollow Au nanoshells are studied that include sphere, disk, triangular prism, rod, ellipsoid, and rectangular block. Multilayered Mie theory and discrete dipole approximation were used to determine the LSPR peak position and LSPR sensitivity as a function of size, shell thickness, shape, and aspect ratio. The change in LSPR peak wavelength per unit refractive index is defined as the sensitivity, and interesting results were obtained from the analysis. The rectangular block and rod-shaped Au nanoshells have shown maximum LSPR sensitivity when compared to other shaped Au nanoshells. In addition, increased sensitivity was observed for higher aspect ratio as well as for smaller shell thicknesses. The results are rationalized based on the inner and outer surface plasmonic coupling.
等离子体纳米颗粒与生物分子结合时折射率的变化通常用于基于局域表面等离子体共振（LSPR）的生物传感器和生物传感平台中。在本研究中，通过理论建模研究了中空金（Au）纳米壳的等离子体灵敏度，其中探讨了形状、尺寸、壳厚度和纵横比的影响。研究了不同形状的中空Au纳米壳，包括球体、圆盘、三角棱柱、棒体、椭球体和长方体。使用多层米氏理论和离散偶极近似来确定作为尺寸、壳厚度、形状和纵横比函数的LSPR峰位置和LSPR灵敏度。将每单位折射率的LSPR峰波长变化定义为灵敏度，分析得出了有趣的结果。与其他形状的Au纳米壳相比，长方体和棒状Au纳米壳表现出最大的LSPR灵敏度。此外，对于更高的纵横比以及更小的壳厚度，观察到灵敏度增加。基于内表面和外表面等离子体耦合对结果进行了合理化解释。
