Multiple Label-Free Detection of Antigen−Antibody Reaction Using Localized Surface Plasmon Resonance-Based Core−Shell Structured Nanoparticle Layer Nanochip

Faculty of Engineering, Okayama University of Science, Okayama, Okayama, Japan
Analytical Chemistry (Impact Factor: 5.64). 10/2006; 78(18):6465-75. DOI: 10.1021/ac0608321
Source: PubMed


In this research, a localized surface plasmon resonance (LSPR)-based bioanalysis method for developing multiarray optical nanochip suitable for screening bimolecular interactions is described. LSPR-based label-free monitoring enables to solve the problems of conventional methods that require large sample volumes and time-consuming labeling procedures. We developed a multiarray LSPR-based nanochip for the label-free detection of proteins. The multiarray format was constructed by a core-shell-structured nanoparticle layer, which provided 300 nanospots on the sensing surface. Antibodies were immobilized onto the nanospots using their interaction with Protein A. The concentrations of antigens were determined from the peak absorption intensity of the LSPR spectra. We demonstrated the capability of the array measurement using immunoglobulins (IgA, IgD, IgG, IgM), C-reactive protein, and fibrinogen. The detection limit of our label-free method was 100 pg/mL. Our nanochip is readily transferable to monitor the interactions of other biomolecules, such as whole cells or receptors, with a massively parallel detection capability in a highly miniaturized package. We anticipate that the direct label-free optical immunoassay of proteins reported here will revolutionize clinical diagnosis and accelerate the development of hand-held and user-friendly point-of-care devices.

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Available from: Naoki Nagatani, Apr 25, 2014
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    • "The change in integrated absorbance was measured, rather than an LSPR peak shift. Antigens were detected for concentrations in the region of 100 pg/mL (Endo, et al., 2006). "
    Nanofabrication, 12/2011; , ISBN: 978-953-307-912-7
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    • "In particular, when binding molecules to the surface of LSPparticles , the according increase in the refractive index causes the extinction resonances to red-shift, as reported in various studies on the real-time molecular binding monitored by simple optical transmission spectrometry [3] [4] [5]. Among the studied analytes, LSP-based detection has been essayed with, e.g., heavy metal ions [6], toxin [7], glucose [8], nucleic acids [9], biotin-streptavidin [10], or antigen-antibody interactions [11] [12]. An ordered array of similar particles is usually applied for a high signal-to-noise ratio, with recent developments aiming at single molecule detection [13] [14]. "
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    • "These charge density oscillations are simply defined as LSPR [30]. Gold nanoparticles are mainly used for LSPR excitation and development of respective optical biosensors for medical and food applications as reported by Endo et al. [31] [32] [33] [34] [35]. Several recent studies indicate "
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