Label-free optical biosensor based on localized surface plasmon resonance of immobilized gold nanorods

Huang, Haowen; Tang, Chunran; Zeng, Yanwei; Yu, Xianyong; Liao, Bo; Xia, Xiaodong; Yi, Pinggui; Chu, Paul K.

doi:10.1016/j.colsurfb.2009.01.014

Cited by 50 publications

(21 citation statements)

References 29 publications

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“…The total peak shift of the longitudinal SP bands, which was induced by the adsorption of antibodies and antigens, was about 123 nm. This peak shift is much larger than that observed in the previous work 10 and difficult to explain in terms of simple refractive index changes around the NRs. 4 Structural changes of the polyion layers should be taken into account.…”

Section: ¹1contrasting

confidence: 75%

“…4 Structural changes of the polyion layers should be taken into account. In the previous work, 10 NRs were fixed on a glass substrate with alkanethiols. Molecular assemblies of the hydrophobic alkanethiols were not affected by adsorption of the hydrophilic polypeptide.…”

Section: ¹1mentioning

confidence: 99%

“…46 In previous papers, label-free optical sensors based on peak shifts of the longitudinal SP bands have been used to determine refractive indices of solvents 7 and to detect avidin biotin conjugation 8 and antibodyantigen binding. 9, 10 We also reported that longitudinal SP bands of NRs on a clean surface of a glass substrate showed peak shifts when they were immersed in some solvents.7 However, the peak shift from water to chloroform (36 nm) was much smaller than the half bandwidth of NRs (205 nm). It was shown that the refractive indices of the surrounding medium did not perturb the local refractive indices of the NRs on a glass substrate.…”

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confidence: 93%

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Label-free Biosensor Using Polyion-modified Gold Nanorods Adsorbed on a Glass Substrate

Honda¹,

Kawazumi²,

Nakashima³

et al. 2010

Chemistry Letters

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Gold nanorods (NRs), which were modified with polyions, were fixed on polycation-modified glass substrates. Adsorption of antibodies and antigens on the glass substrates induced large peak shifts (44 nm) of longitudinal surface plasmon bands in the near-infrared region. The shifts were assignable to changes of refractive indices of polyion layers at the glass surfaces.Gold nanorods (NRs) are rod-shaped nanoparticles that exhibit transverse and longitudinal surface plasmon (SP) bands in the visible and near-infrared (near-IR) regions, respectively. 13 The positions of the SP bands are tunable depending on the shape of the NRs and the refractive indices of their surroundings. 46 In previous papers, label-free optical sensors based on peak shifts of the longitudinal SP bands have been used to determine refractive indices of solvents 7 and to detect avidin biotin conjugation 8 and antibodyantigen binding. 9, 10 We also reported that longitudinal SP bands of NRs on a clean surface of a glass substrate showed peak shifts when they were immersed in some solvents.7 However, the peak shift from water to chloroform (36 nm) was much smaller than the half bandwidth of NRs (205 nm). It was shown that the refractive indices of the surrounding medium did not perturb the local refractive indices of the NRs on a glass substrate.In the present work, NRs were deposited on a glass substrate through electrostatic interaction between polyanions on NRs and polycationic-modified surfaces. Peak shifts of the longitudinal SP bands were monitored as a function of concentration of antigen in aqueous solution.The NRs were synthesized by a photochemical method 11 in a joint research project between Mitsubishi Materials Corp. and Dai-Nihon-Toryo Co., Ltd. The initial ¦ potential of the NRs was +20 mV, which originates from hexadecyltrimethylammonium bromide (CTAB) bilayers on the NR surfaces. A typical procedure for surface modification of NRs was as follows. Asprepared NRs were centrifuged twice at 15000 © g for 10 min and decanted to remove excess CTAB from the solution. The positively charged surfaces of the NRs were wrapped with poly(styrene sulfonate) (PSS, M w = 70000 g mol ¹1, Aldrich) through electrostatic interaction.12,13 The PSS-modified NRs are denoted PSSNR. The ¦ potential of PSSNRs was typically ¹21.5 mV. The absorption spectrum of a PSSNR solution shows double peaks that are typical for colloidal NRs, indicating modification by PSS of the NRs without formation of aggregates.To deposit PSSNRs on a glass substrate, water-soluble polymers were coated on the substrate layer-by-layer. 7 The resulting hydrophilic glass substrate was sequentially immersed in a poly(allylamine hydrochloride) (PAH, M w = 15000 g mol , 20 min) to obtain a multilayered polymer film (polyion substrate). The outermost layer on the substrate was positively charged due to the presence of PAH. The polyionsubstrate was then immersed in a PSSNR solution for 24 h to deposit PSS NR on the substrate surface. After immersion, the substrate was washed with water an...

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Section: ¹1contrasting

confidence: 75%

Section: ¹1mentioning

confidence: 99%

mentioning

confidence: 93%

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Label-free Biosensor Using Polyion-modified Gold Nanorods Adsorbed on a Glass Substrate

Honda¹,

Kawazumi²,

Nakashima³

et al. 2010

Chemistry Letters

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“…The Au 2 S/AuAgS-coated GNRs immobilized on glass slides have the advantage of keeping a constant concentration of nanoparticles throughout the experiments, monitoring its plasmon absorption intensity change at a fixed wavelength and suitable for dynamic SPR measurements in immunoassays, as described in our previous report [36]. A glass slide was transformed into a sensor firstly by the immobilization of Au 2 S/AuAgS-coated GNRs on a thiol-terminated glass substrate.…”

Section: Fabrication Of Integrated Lspr Optical Biosensormentioning

confidence: 99%

A Localized Surface Plasmon Resonance Biosensor Based on Integrated Controllable Au2S/AuAgS-Coated Gold Nanorods Composite

et al. 2010

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In this work, we have demonstrated that the exquisite optical properties based on localized surface plasmon resonance (LSPR) of Au 2 S/AuAgS-coated gold nanorods (Au 2 S/AuAgS-coated GNRs) can be utilized to develop a simple and sensitive biosensor, and goat antihuman IgG can be detected by the human IgG probe as low as 0.2 nM. Moreover, we introduce an integrated LSPR biosensor constructed by integrating Au 2 S/AuAgS-coated GNRs immobilized on glass slide and isolated Au 2 S/ AuAgS-coated GNRs in the form of liquid. The detection of target binding was performed via direct spectral changes induced by changes of refractive index in the vicinity of individual particles. The integrated LSPR optical biosensor is label-free, cost-effective, and easy to fabricate and requires only a visible/near-infrared spectrometer for detection purposes. Additionally, the investigation on the mutual influence of the two types of nanorods in the integrated LSPR biosensor was performed. The results of separate experiments indicate that the nanorods in the form of isolate or in integrated exhibit a similar behavior.

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“…Common techniques for fabricating nanostructured transducers include immobilization of nanoparticles on chemically modified substrates, 14,15 nanolithography (including nanosphere lithography, 16,17 and electron-beam lithography 18,19 ), and evaporation of a thin layer of metal on a glass surface followed by thermal annealing. 20 Although immobilized nanoparticles (e.g., nanorods, nanostars, nanoprisms, nanorice) show good LSPR responses, there can be some disadvantages with regard to stability and reproducibility.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical synthesis of nanostructured gold film for the study of carbohydrate–lectin interactions using localized surface plasmon resonance spectroscopy

Bhattarai

Sharma

Fujikawa

et al. 2015

Carbohydrate Research

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Localized surface plasmon resonance (LSPR) spectroscopy is a label-free chemical and biological molecular sensing technique whose sensitivity depends upon development of nanostructured transducers. Herein, we report an electrodeposition method for fabricating nanostructured gold films (NGFs) that can be used as transducers in LSPR spectroscopy. The NGF was prepared by electrodepositing gold from potassium dicyanoaurate solution onto a flat gold surface using two sequential controlled potential steps. Imaging by scanning electron microscopy reveals a morphology consisting of randomly configured block-like nanostructures. The bulk refractive index sensitivity of the prepared NGF is 100 ± 2 nm RIU−1 and the initial peak in the reflectance spectrum is at 518 ± 1 nm under N2(g). The figure of merit is 1.7. In addition, we have studied the interaction between carbohydrate (mannose) and lectin (Concanavalin A) on the NGF surface using LSPR spectroscopy by measuring the interaction of 8-mercaptooctyl-α-D-mannopyranoside (αMan-C8-SH) with Concanavalin A by first immobilizing αMan-C8-SH in mixed SAMs with 3,6-dioxa-8-mercaptooctanol (TEG-SH) on the NGF surface. The interaction of Con A with the mixed SAMs is confirmed using electrochemical impedance spectroscopy. Finally, the NGF surface was regenerated to its original sensitivity by removing the SAM and the bound biomolecules. The results from these experiments contribute toward the development of inexpensive LSPR based sensors that could be useful for studying glycan–protein interactions and other bioanalytical purposes.

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Label-free optical biosensor based on localized surface plasmon resonance of immobilized gold nanorods

Cited by 50 publications

References 29 publications

Label-free Biosensor Using Polyion-modified Gold Nanorods Adsorbed on a Glass Substrate

Label-free Biosensor Using Polyion-modified Gold Nanorods Adsorbed on a Glass Substrate

A Localized Surface Plasmon Resonance Biosensor Based on Integrated Controllable Au2S/AuAgS-Coated Gold Nanorods Composite

Electrochemical synthesis of nanostructured gold film for the study of carbohydrate–lectin interactions using localized surface plasmon resonance spectroscopy

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