Design and Simple Assembly of Gold Nanostar Bioconjugates for Surface-Enhanced Raman Spectroscopy Immunoassays
Immunoassays using Surface-Enhanced Raman Spectroscopy are especially interesting on account not only of their increased sensitivity, but also due to its easy translation to point-of-care formats. The bases for these assays are bioconjugates of polyclonal antibodies and anisotropic gold nanoparticle...
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| Format: | Article |
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MDPI AG
2019-11-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/9/11/1561 |
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| author | Maria João Oliveira Miguel P. de Almeida Daniela Nunes Elvira Fortunato Rodrigo Martins Eulália Pereira Hugh J. Byrne Hugo Águas Ricardo Franco |
| author_facet | Maria João Oliveira Miguel P. de Almeida Daniela Nunes Elvira Fortunato Rodrigo Martins Eulália Pereira Hugh J. Byrne Hugo Águas Ricardo Franco |
| author_sort | Maria João Oliveira |
| collection | DOAJ |
| description | Immunoassays using Surface-Enhanced Raman Spectroscopy are especially interesting on account not only of their increased sensitivity, but also due to its easy translation to point-of-care formats. The bases for these assays are bioconjugates of polyclonal antibodies and anisotropic gold nanoparticles functionalized with a Raman reporter. These bioconjugates, once loaded with the antigen analyte, can react on a sandwich format with the same antibodies immobilized on a surface. This surface can then be used for detection, on a microfluidics or immunochromatographic platform. Here, we have assembled bioconjugates of gold nanostars functionalized with 4-mercaptobenzoic acid, and anti-horseradish peroxidase antibodies. The assembly was by simple incubation, and agarose gel electrophoresis determined a high gold nanostar to antibody binding constant. The functionality of the bioconjugates is easy to determine since the respective antigen presents peroxidase enzymatic activity. Furthermore, the chosen antibody is a generic immunoglobulin G (IgG) antibody, opening the application of these principles to other antibody-antigen systems. Surface-Enhanced Raman Spectroscopy analysis of these bioconjugates indicated antigen detection down to 50 µU of peroxidase activity. All steps of conjugation were fully characterized by ultraviolet-visible spectroscopy, dynamic light scattering, <inline-formula> <math display="inline"> <semantics> <mi>ζ</mi> </semantics> </math> </inline-formula>-Potential, scanning electron microscopy, and agarose gel electrophoresis. Based on the latter technique, a proof-of-concept was established for the proposed immunoassay. |
| first_indexed | 2024-12-20T06:22:05Z |
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| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-12-20T06:22:05Z |
| publishDate | 2019-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-f28a9a2697504cee800bb61483e8072d2022-12-21T19:50:23ZengMDPI AGNanomaterials2079-49912019-11-01911156110.3390/nano9111561nano9111561Design and Simple Assembly of Gold Nanostar Bioconjugates for Surface-Enhanced Raman Spectroscopy ImmunoassaysMaria João Oliveira0Miguel P. de Almeida1Daniela Nunes2Elvira Fortunato3Rodrigo Martins4Eulália Pereira5Hugh J. Byrne6Hugo Águas7Ricardo Franco8UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, PortugalREQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, 4169-007 Porto, PortugalCENIMAT-I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, PortugalCENIMAT-I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, PortugalCENIMAT-I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, PortugalREQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, 4169-007 Porto, PortugalFOCAS Research Institute, Technological University Dublin, Kevin Street, Dublin 8, IrelandCENIMAT-I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, PortugalUCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, PortugalImmunoassays using Surface-Enhanced Raman Spectroscopy are especially interesting on account not only of their increased sensitivity, but also due to its easy translation to point-of-care formats. The bases for these assays are bioconjugates of polyclonal antibodies and anisotropic gold nanoparticles functionalized with a Raman reporter. These bioconjugates, once loaded with the antigen analyte, can react on a sandwich format with the same antibodies immobilized on a surface. This surface can then be used for detection, on a microfluidics or immunochromatographic platform. Here, we have assembled bioconjugates of gold nanostars functionalized with 4-mercaptobenzoic acid, and anti-horseradish peroxidase antibodies. The assembly was by simple incubation, and agarose gel electrophoresis determined a high gold nanostar to antibody binding constant. The functionality of the bioconjugates is easy to determine since the respective antigen presents peroxidase enzymatic activity. Furthermore, the chosen antibody is a generic immunoglobulin G (IgG) antibody, opening the application of these principles to other antibody-antigen systems. Surface-Enhanced Raman Spectroscopy analysis of these bioconjugates indicated antigen detection down to 50 µU of peroxidase activity. All steps of conjugation were fully characterized by ultraviolet-visible spectroscopy, dynamic light scattering, <inline-formula> <math display="inline"> <semantics> <mi>ζ</mi> </semantics> </math> </inline-formula>-Potential, scanning electron microscopy, and agarose gel electrophoresis. Based on the latter technique, a proof-of-concept was established for the proposed immunoassay.https://www.mdpi.com/2079-4991/9/11/1561surface enhanced raman spectroscopy surfaceenhanced raman spectroscopygold nanostarsgold nanoparticlesimmunoconjugatesimmunoassayhorseradish peroxidaseraman reporteragarose gel electrophoresisdynamic light scattering |
| spellingShingle | Maria João Oliveira Miguel P. de Almeida Daniela Nunes Elvira Fortunato Rodrigo Martins Eulália Pereira Hugh J. Byrne Hugo Águas Ricardo Franco Design and Simple Assembly of Gold Nanostar Bioconjugates for Surface-Enhanced Raman Spectroscopy Immunoassays Nanomaterials surface enhanced raman spectroscopy surface enhanced raman spectroscopy gold nanostars gold nanoparticles immunoconjugates immunoassay horseradish peroxidase raman reporter agarose gel electrophoresis dynamic light scattering |
| title | Design and Simple Assembly of Gold Nanostar Bioconjugates for Surface-Enhanced Raman Spectroscopy Immunoassays |
| title_full | Design and Simple Assembly of Gold Nanostar Bioconjugates for Surface-Enhanced Raman Spectroscopy Immunoassays |
| title_fullStr | Design and Simple Assembly of Gold Nanostar Bioconjugates for Surface-Enhanced Raman Spectroscopy Immunoassays |
| title_full_unstemmed | Design and Simple Assembly of Gold Nanostar Bioconjugates for Surface-Enhanced Raman Spectroscopy Immunoassays |
| title_short | Design and Simple Assembly of Gold Nanostar Bioconjugates for Surface-Enhanced Raman Spectroscopy Immunoassays |
| title_sort | design and simple assembly of gold nanostar bioconjugates for surface enhanced raman spectroscopy immunoassays |
| topic | surface enhanced raman spectroscopy surface enhanced raman spectroscopy gold nanostars gold nanoparticles immunoconjugates immunoassay horseradish peroxidase raman reporter agarose gel electrophoresis dynamic light scattering |
| url | https://www.mdpi.com/2079-4991/9/11/1561 |
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