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SERS-based immunoassay on 2D-arrays of Au@Ag core-shell nanoparticles: influence of the sizes of the SERS probe and sandwich immunocomplex on the sensitivity
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Metadata
Document Title
SERS-based immunoassay on 2D-arrays of Au@Ag core-shell nanoparticles: influence of the sizes of the SERS probe and sandwich immunocomplex on the sensitivity
Author
Karn-Orachai K.,Sakamoto K.,Laocharoensuk R.,Bamrungsap S.,Dharakul T.,Miki K.
Name from Authors Collection
Affiliations
National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan; Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan; National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani, 12120, Thailand; Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand
Type
Article
Source Title
RSC Advances
ISSN
20462069
Year
2017
Volume
7
Issue
23
Open Access
All Open Access, Gold
Publisher
Royal Society of Chemistry
DOI
10.1039/c7ra00154a
Abstract
We report a sandwich-type SERS-based immunoassay using a two-dimensional (2D) array of gold core@silver shell (Au@Ag) nanoparticles (NPs) as the SERS substrate and antibody-conjugated gold NPs labeled with 4-mercaptobenzoic acid (MBA) as the SERS probes. To achieve highly sensitive detection, the size of the SERS probes was first optimized for the immunoassay of Human-IgG (H-IgG), where the Au core size of the SERS probes was varied from 26 to 110 nm in diameter. The maximum SERS intensity was observed at an Au core size of 53 nm. Then, the influence of the size of the sandwich immunocomplexes on the sensitivity was examined by performing sandwich SERS immunoassays for H-IgG and prostate-specific antigen (PSA) using SERS probes with 53 nm Au core size. The sensitivity improvement by using the SERS substrate (2D-array of Au@Ag NPs) instead of an Au evaporated film, which was used as a reference substrate, was evaluated for each immunoassay. The sensitivity improvement for H-IgG and PSA detection was 2.3-fold and 6.4-fold, respectively. The larger sensitivity improvement for the PSA system can be attributed to the smaller immunocomplex of PSA; the shorter separation distance between the SERS probes and the SERS substrate induces stronger plasmon coupling. This result indicates that the sensitivity of the sandwich-type immunoassay performed on the SERS substrate increases with decreasing size of sandwich immunocomplex, suggesting that the sensitivity can be improved by adopting an antibody-fragment with the same affinity for the target antigen as that of the antibody. © The Royal Society of Chemistry.
Industrial Classification
Knowledge Taxonomy Level 1
Knowledge Taxonomy Level 2
Knowledge Taxonomy Level 3
Funding Sponsor
Japan Society for the Promotion of Science; Ministry of Education, Culture, Sports, Science and Technology; Japan Science and Technology Agency; National Science and Technology Development Agency; National Institute for Materials Science; National Nanotechnology Center; Yazaki Memorial Foundation for Science and Technology
License
CC BY-NC
Rights
Author
Publication Source
Scopus