Factors Influencing the Surface Functionalization of Citrate Stabilized Gold Nanoparticles with Cysteamine, 3-Mercaptopropionic Acid or l -Selenocystine for Sensor Applications

SAKELLARI, Georgia I., HONDOW, Nicole and GARDINER, Philip H.E. (2020). Factors Influencing the Surface Functionalization of Citrate Stabilized Gold Nanoparticles with Cysteamine, 3-Mercaptopropionic Acid or l -Selenocystine for Sensor Applications. Chemosensors, 8 (3), e80.

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Open Access URL: https://www.mdpi.com/2227-9040/8/3/80 (Published online)
Link to published version:: https://doi.org/10.3390/chemosensors8030080
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    Abstract

    Thiols and selenides bind to the surface of gold nanoparticles (AuNPs) and thus provide suitable platforms for the fabrication of sensors. However, the co-existence of adsorbed citrate on the surface of the nanoparticles can influence their functionalization behavior and potentially their sensing performance measured by the extent of particle aggregation. In this study, the functionalization of purchased (7.3 ± 1.2 nm) and in-house prepared AuNPs (13.8 ± 1.2 nm), under the same experimental conditions with either cysteamine (Cys), 3-mercaptopropionic acid (3-MPA), or l-selenocystine (SeCyst) was investigated. 1H-NMR measurements showed distinct citrate signatures on the in-house synthesized citrate-stabilized AuNPs, while no citrate signals were detected on the purchased AuNPs other than evidence of the presence of α-ketoglutaric acid. Carboxylate-containing species attributed to either citrate or α-ketoglutaric acid were identified in all functionalized AuNPs. ATR-FTIR spectroscopy confirmed the functionalization of AuNPs with Cys and 3-MPA, and energy dispersive X-ray (EDX) spectroscopy measurements suggested the formation of SeCyst functionalized AuNPs. Co-adsorption rather than displacement by the functionalizing agents and carboxylate-containing molecules was indicated, which for Cys and SeCyst functionalized AuNPs was also the aggregation limiting factor. In contrast, the behavior of 3-MPA functionalized AuNPs could be attributed to electrostatic repulsions between the functionalized groups.

    Item Type: Article
    Additional Information: ** From MDPI via Jisc Publications Router ** Licence for this article: https://creativecommons.org/licenses/by/4.0/ **Journal IDs: eissn 2227-9040 **History: published 31-08-2020; accepted 26-08-2020
    Uncontrolled Keywords: gold nanoparticles, cysteamine, 3-Mercaptopropionic Acid, l-Selenocystine, functionalization, self-assembled monolayers, sensor applications
    Identification Number: https://doi.org/10.3390/chemosensors8030080
    Page Range: e80
    SWORD Depositor: Colin Knott
    Depositing User: Colin Knott
    Date Deposited: 02 Sep 2020 12:20
    Last Modified: 02 Sep 2020 12:20
    URI: http://shura.shu.ac.uk/id/eprint/27142

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