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Proceedings ArticleDOI

A novel 'Gold on Gold' biosensing scheme for an on-fiber immunoassay

05 May 2015-Proceedings of SPIE (International Society for Optics and Photonics)-Vol. 9506, pp 492-498
TL;DR: A novel „gold on gold” biosensing scheme for absorbance based fiber-optic biosensor that demonstrated the potential in improving the limit of detection for the fiber- optic biosensors and its response was found to be more than five-fold higher than the control bioassay.
Abstract: In this paper, we propose a novel „gold on gold‟ biosensing scheme for absorbance based fiber-optic biosensor. First, a self-assembled monolayer of gold nanoparticles is formed at the sensing region of the fiber-optic probe by incubating an amino-silanized probe in a colloidal gold solution. Thereafter, the receptor moieties, i.e. Human immunoglobulin G (HIgG) were immobilized by using standard alkanethiol and classic carbodiimide coupling chemistry. Finally, biosensing experiments were performed with different concentrations of gold nanoparticle-tagged analyte, i.e. Goat anti- Human immunoglobulin G (Nanogold-GaHIgG). The sensor response was observed to be more than five-fold compared to the control bioassay, in which the sensor matrix was devoid of gold nanoparticle film. Also, the response was found to be ~10 times higher compared to the FITC-tagged scheme and ~14.5 times better compared to untagged scheme. This novel scheme also demonstrated the potential in improving the limit of detection for the fiber-optic biosensors.
Citations
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Journal ArticleDOI
TL;DR: A new platform for sensitive detection of amyloid fibrils and monomer of α-Synuclein (independently as well as in mixtures) for potential applications in inhibition and aggregation based studies is introduced.
Abstract: α-Synuclein protein, whose aggregation is associated with Parkinson’s disease, is detected using a compact, label-free, localized surface plasmon resonance (LSPR) based optical sensor. U-shaped fiber optic probe immobilized with gold nanoparticles (GNP), and subsequently functionalized using a film of chitosan was used as a sensing platform. The chitosan film acts as a sensitive and selective polysaccharide bioreceptor for detection of α-Synuclein. Binding of amyloid proteins to this film causes a localized change of dielectric constant surrounding the nanoparticles, leading to a change in the spectrum at the output end of the fiber. The combination of binding rate kinetics and intensity change was measured to develop a robust sensing platform. The sensor could detect the presence of monomers & amyloid fibrils independently up to 70 nM and could differentiate them in mixtures having fibril to monomer ratio from 0.1 to 10, within 15 min. The present study introduces a new platform for sensitive detection of amyloid fibrils and monomer of α-Synuclein (independently as well as in mixtures) for potential applications in inhibition and aggregation based studies.

30 citations

Journal ArticleDOI
TL;DR: In this article, a review of optical fiber biosensors based on luminescence and absorption is presented, where a comprehensive insight of the different aspects that must be taken into account when working with this kind of sensors is provided.

14 citations

Journal ArticleDOI
TL;DR: In this article, a U-shaped polyester waveguide is used for point-of-care (POC) detection of myeloperoxidase, achieving a sensitivity of 6.2 ΔA/RIU.

5 citations

Journal ArticleDOI
TL;DR: In this article, the U-shaped optical fiber probes were fabricated with aggregate-free Au nanoparticles exhibiting a sharp localized surface plasmon resonance (LSPR) spectra, and the process was monitored and controlled in real time through the changes induced into the fiber's extinction spectra by the laser irradiation.
Abstract: A novel experimental methodology is presented for fabricating U-shaped optical fiber probes decorated with aggregate-free Au nanoparticles exhibiting sharp localized surface plasmon resonance (LSPR) spectra. The U-type tip is coated with gold nanoparticles (AuNPs) using a simple and time-efficient dip-coating procedure, without initially taking any care to prevent the formation of nanoparticle aggregates in the coated area. In a second step, the coating was irradiated with a few tens of laser pulses of 5-ns duration at 532 nm with intensities in the range of 2–14 MW/cm2, leading to the formation of aggregate-free LSPR optical fiber probes. The process was monitored and controlled in real time through the changes induced into the fiber’s extinction spectra by the laser irradiation, and the coated fibers were characterized by electron microscopy. The proposed methodology resulted into the fabrication of U-type optical fiber probes coated with AuNPs exhibiting a sharp plasmon peak, which is a perquisite for their application as sensing devices.

5 citations

References
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Journal ArticleDOI
TL;DR: In this paper, a preliminary survey with the electron microscope of various preparations of colloidal gold, a study was made of the process of nucleation and growth in gold colloids, and it was shown that nucleating agents may be identified with reducing agents which form a mixed polymer with chlorauric ion before the reduction to the nucleus takes place.
Abstract: After a preliminary survey with the electron microscope of various preparations of colloidal gold, a study was made of the process of nucleation and growth in gold colloids. It was shown that nucleating agents may be identified with reducing agents which form a mixed polymer with chlorauric ion before the reduction to the nucleus takes place. It was also shown that the law of growth is exponential. The average size, the deviation from the average size and the character of the particle size distribution curve are determined by the amount of gold, the nucleation process and the law of growth.

6,593 citations


"A novel 'Gold on Gold' biosensing s..." refers methods in this paper

  • ...…was then brought under the butane flame and both the sections around the decladded portion were gently pressed towards each other, so as to give the „U‟ shape to the fiber, having diameter of ~1.5 mm. Gold nanoparticles were synthesized using the protocol developed by Turkevich et al. (1951) 10 ....

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Journal ArticleDOI
TL;DR: The basis behind LSPR sensing is described, the latest progress regarding nanostructure fabrication techniques and biosensing applications are summarized, and the challenges that L SPR biosensors should face are discussed.

860 citations


"A novel 'Gold on Gold' biosensing s..." refers background in this paper

  • ...(1), that this absorption is dependent on optical constants of the analyte like refractive index contrast between fiber core material and analyte and absorption coefficient of the analyte....

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  • ...303 2 core analyte CL A r n n      (1)...

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Journal ArticleDOI
TL;DR: Multiplex sensing was demonstrated by the distinct response of the plasmon spectra of the GNrMPs to binding events of three targets, which can play a key role in developing novel optical biosensors for both in vivo and in vitro detection and single-receptor kinetics.
Abstract: Gold nanorods (GNRs) with different aspect ratios were fabricated through seed-mediated growth and surface activation by alkanethiols for the attachment of antibodies to yield gold nanorod molecular probes (GNrMPs). Multiplex sensing was demonstrated by the distinct response of the plasmon spectra of the GNrMPs to binding events of three targets (goat anti-human IgG1 Fab, rabbit anti-mouse IgG1 Fab, rabbit anti-sheep IgG (H+L)). Plasmonic sensors are highly specific and sensitive and can be used to monitor refractive index changes caused by molecular interactions in their immediate vicinity with potential to achieve single-particle biosensing. This technique can play a key role in developing novel optical biosensors for both in vivo and in vitro detection and single-receptor kinetics.

503 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the recent advances in the development of gold nanoparticles-based optical, electrochemical, and piezoelectric biosensors is presented.
Abstract: The unique properties of gold nanoparticles have stimulated the increasing interest in the application of GNPs in interfacing biological recognition events with signal transduction and in designing biosensing devices exhibiting novel functions. The optical properties of GNPs provide wide range opportunities for construction optical biosensors. The excellent biocompatibility, conductivity, catalytic properties and high surface-to-volume ratio and high density of GNPs facilitate extensive application of GNPs in construction of electrochemical and piezoelectric biosensors with enhanced analytical performance with respect to other biosensor designs. In this article, the recent advances in construction of GNP-based optical, electrochemical and piezoelectric biosensors are reviewed, and some illustrative examples given, with a focus on the roles GNPs play in the biosensing process and the mechanism of GNPs for improving the analytical performances. Finally, the review concludes with an outline of present and future research for the real-world applications.

409 citations


"A novel 'Gold on Gold' biosensing s..." refers background in this paper

  • ...(2), refractive loss also depends on the refractive index of the analyte....

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  • ...2 10log a L r NA P NA         (2)...

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Journal ArticleDOI
TL;DR: A sensor for sensitive measurement of refractive index (RI) with the help of optical absorbance properties of gold nanoparticles (GNP) coupled to an efficient optical transducer in the form of a U-bent fiber optic probe is described.

261 citations