Improved method for estimating adlayer thickness and bulk RI change for gold nanocrescent sensors

Abumazwed, Ahmed; Kubo, Wakana; Tanaka, Takuo; Kirk, Andrew G.

doi:10.1038/s41598-018-24950-7

Cited by 8 publications

(6 citation statements)

References 22 publications

(22 reference statements)

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“…For example, dielectric microresonators were suggested for thickness determination with sub-nanometer precision . In another research, this was achieved using localized plasmon resonances of gold nanocrescents . These platforms usually require complex optical spectroscopy at wavelengths above 1 μm and also require advanced nanofabrication techniques, limiting the broad applicability of these sensors.…”

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confidence: 93%

“…19 In another research, this was achieved using localized plasmon resonances of gold nanocrescents. 20 These platforms usually require complex optical spectroscopy at wavelengths above 1 μm and also require advanced nanofabrication techniques, limiting the broad applicability of these sensors. In addition, for the ring resonator case, the area of a single sensing site is about 50 μm 2 .…”

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confidence: 99%

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Entangled Nanoplasmonic Cavities for Estimating Thickness of Surface-Adsorbed Layers

et al. 2020

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Plasmonic sensors provide real-time and label-free detection of biotargets with unprecedented sensitivity and detection limit. However, they usually lack the ability to estimate the thickness of the target layer formed on top of the sensing surface. Here, we report a sensing modality based on reflection spectroscopy of a nanoplasmonic Fabry–Perot cavity array, which exhibits characteristics of both surface plasmon polaritons and localized plasmon resonances and outperforms its conventional counterparts by providing the thickness of the surface-adsorbed layers. Through numerical simulations, we demonstrate that the designed plasmonic surface resembles two entangled Fabry–Perot cavities excited from both ends. Performance of the device is evaluated by studying sensor response in the refractive index (RI) measurement of aqueous glycerol solutions and during formation of a surface-adsorbed layer consisting of protein (i.e., NeutrAvidin) molecules. By tracking the resonance wavelengths of the two modes of the nanoplasmonic surface, it is therefore possible to measure the thickness of a homogeneous adsorbed layer and RI of the background solution with precisions better than 4 nm and 0.0001 RI units. Using numerical simulations, we show that the thickness estimation algorithm can be extended for layers consisting of nanometric analytes adsorbed on an antibody-coated sensor surface. Furthermore, performance of the device has been evaluated to detect exosomes. By providing a thickness estimation for adsorbed layers and differentiating binding events from background RI variations, this device can potentially supersede conventional plasmonic sensors.

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confidence: 99%

Entangled Nanoplasmonic Cavities for Estimating Thickness of Surface-Adsorbed Layers

et al. 2020

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“…A Fano resonance occurs when a discrete (subradiant) and a continuous state (superradiant) overlap and interfere, leading to a spectral feature exhibiting a strong dependence on the local environment that can be harnessed in sensing applications. − As reported elsewhere, Fano resonances in nanocrescents are influenced by the tip-to-tip distance as well as the height of the structure and result from interference between the dipolar mode of the tips along the height axis (acting as the discrete state) and the quadrupolar mode within the plane of the crescent (which constitutes the continuous state). The sensitivity of the plasmonic response of nanocrescents to their dimensions leads to highly tunable optical properties that provide versatility for many applications such as biological and chemical sensing, nanomedicine, nanolasing, and catalysis. ,,,− For example, Park et al fabricated nanocrescent antennas on mesoporous silica nanospheres for cellular imaging, molecular targeting, and drug delivery . Zhang and co-workers demonstrate the potential of gold nanocrescents in asymmetric catalysis and as a surface-enhanced Raman scattering (SERS) platform for the chiral detection of molecules …”

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confidence: 99%

Plasmonic Properties of Self-Assembled Gold Nanocrescents: Implications for Chemical Sensing

Côté,

Boukouvala,

Richard-Daniel

et al. 2024

ACS Appl. Nano Mater.

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A bottom-up approach, the Langmuir−Blodgett technique, is used for the preparation of composite thin films of gold nanoparticles and polymers: poly(styrene-b-2-vinylpyridine), poly-2-vinylpyridine, and polystyrene. The selfassembly of poly(styrene-b-2-vinylpyridine) at the air−water interface leads to the formation of surface micelles, which serve as a template for the organization of gold nanoparticles into ring assemblies. By using poly-2-vinylpyridine in conjunction with low surface pressure, the distance between nanostructures can be increased, allowing for optical characterization of single nanostructures. Once deposited on a solid substrate, the preorganized gold nanoparticles are subjected to further growth by the reduction of additional gold, leading to a variety of nanostructures which can be divided into two categories: nanocrescents and circular arrays of nanoparticles. The optical properties of individual structures are investigated by optical dark-field spectroscopy and numerical calculations. The plasmonic behavior of the nanostructures is elucidated through the correlation of optical properties with structural features and the identification of dominant plasmon modes. Being based on a self-assembly approach, the reported method allows for the formation of interesting plasmonic materials under ambient conditions, at a relatively large scale, and at low cost. These attributes, in addition to the resonances located in the near-infrared region of the spectrum, make nanocrescents candidates for biological and chemical sensing.

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“…LSP characteristics, such as the absorption of light and the generation of electric fields around metal nanostructures, strongly depend on the shapes of the metal nanostructures and the surrounding dielectric environment (refractive index, RI) [7][8][9]. Therefore, metal nanostructures have been studied for their applications in highly sensitive, label-free sensors that detect surrounding RI changes caused by adsorption or molecule interaction on metal nanostructure surfaces [10,11]. Because the RI sensitivity depends on the properties of the LSP mode, various shapes of metal nanostructures have been studied for improving sensitivity [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Metal-Insulator-Metal Nanostructures Composed of Au-MgF2-Au and Its Potential in Responding to Two Different Factors in Sample Solutions Using Individual Plasmon Modes

et al. 2022

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In this paper, metal–insulator–metal (MIM) nanostructures, which were designed to exhibit two absorption peaks within 500–1100 nm wavelength range, were fabricated using magnesium difluoride (MgF2) as the insulator layer. Since the MIM nanostructures have two plasmon modes corresponding to the absorption peaks, they independently responded to the changes in two phases: the surrounding medium and the inside insulator layer, the structure is expected to obtain multiple information from sample solution: refractive index (RI) and molecular interaction between solution components and the insulator layer. The fabricated MIM nanostructure had a diameter of 139.6 ± 2.8 nm and a slope of 70°, and exhibited absorption peaks derived from individual plasmon modes at the 719 and 907 nm wavelengths. The evaluation of the response to surrounding solution component of the MIM nanostructures revealed a linear response of one plasmon mode toward the RI of the surrounding medium and a large blue shift of the other plasmon mode under conditions where glycerol was present at high concentration. From optical simulation and the evaluation of the MgF2 fabricated by deposition, the blue shift was expected to be due to the swelling of MgF2 interacting with the hydroxyl groups abundantly included in the glycerol molecules. The results indicated the individual responses of two plasmon modes in MIM nanostructures toward medium components, and brought the prospect for the simultaneous measurement of multiple elements using two or more plasmon modes.

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Improved method for estimating adlayer thickness and bulk RI change for gold nanocrescent sensors

Cited by 8 publications

References 22 publications

Entangled Nanoplasmonic Cavities for Estimating Thickness of Surface-Adsorbed Layers

Entangled Nanoplasmonic Cavities for Estimating Thickness of Surface-Adsorbed Layers

Plasmonic Properties of Self-Assembled Gold Nanocrescents: Implications for Chemical Sensing

Fabrication of Metal-Insulator-Metal Nanostructures Composed of Au-MgF2-Au and Its Potential in Responding to Two Different Factors in Sample Solutions Using Individual Plasmon Modes

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