Engineering a Localized Surface Plasmon Resonance Platform for Molecular Biosensing

Abstract

In this work, we introduce a new perspective on the development of Localized Surface Plasmon Resonance (LSPR) optical biosensors. Computational simulations, focused on the assessment of the LSPR spectrum and spatial distribution of the electromagnetic field enhancement near a metallic nanoparticle, elucidated the behavior of crucial parameters, as figure of merit, bulk and molecular sensitivity, which governs a LSPR sensor performance. Gold and silver nanospheres were explored as starting point to assess plasmonic optical characteristics of the nanostructured sensor platform. Here, for the first time in the literature, Campbell's model was evaluated exploiting a NP size-dependence approach. The theoretical analyses indicate a nonlinear behavior of the bulk and molecular sensitivity as function of the NP size. Substantial LSPR peak shifts due to the adsorption of molecules layer on a NP surface were observed for nanoparticles with ~5 nm and ~40 nm radius. Moreover, on molecular sensing, LSPR peak shift is also determined by the thickness of adsorbed molecular shell layers. We observed that for 40 nm radius gold and silver nanospheres, significant LSPR peak shift could be induced by small (few nm) thickness change of the adsorbate shell layer. Moreover, this work provides insights on the LSPR behavior due to adsorption of molecular layer on a NP surface, establishing a new paradigm on engineering LSPR biosensor. Furthermore, the proposed approach can be extended to engineer an efficiently use of different nanostructures on molecular sensing.

Structural, Optical and Electrical Properties of Al+MoO3 and Au+MoO3 Thin Films Prepared by Magnetron Codeposition

“…The broadening of the peak is the consequence of the broadening of the Au NP size distribution from A1 to A3 (see the parameter σ R , Table 2 ). Otherwise, the width of the plasmon peak should have the opposite behavior [ 31 , 40 ].…”

Effects of Different Aspect Ratios and Junction Lengths on the Coupled Plasmon Gold Nanorod Dimers

“…Sensing performance can also be evaluated by exploring the Figure of Merit (FoM) factor. The FoM is defined as the ratio of bulk sensitivity to the full width at half maximum (FWHM) (Farooq, and Araujo 2018), and is expressed as: Numerical values for the bulk sensitivity of AuNR dimer were identified as 381 nm/RIU, which is higher than single nanorod value (300 nm/RIU). The AuNR dimer also presents a higher figure of merit (11.7) after linked by silica cylinder with appropriate aspect ratio (AR = 3).…”

“…respect to the change in RI unit (RIU) of the medium, and its unit is eV/RIU or nm/RIU (Farooq, and Araujo 2018). The most commonly employed equation for refractive index (RI) based sensitivity or bulk sensitivity can be written as:…”

Plasmonic nanostructures for advanced interfacial solarvapor generation

“…(Localized Surface Plasmon, LSP)源于光与金属颗粒 表面自由电子集体振荡的耦合. 在Mie散射理论中, 由 于边界条件的限制, 本征模式由连续解转变为离散的 级数解, 表现为不同角动量量子数l所对应的共振模式 的叠加(图1(c)) [17] . 通常当颗粒的尺寸远小于波长时, 只有l=1的模式较为显著, 对应ε=−2ε m 处的Frohlich窄 带共振吸收 [18] .…”