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Article

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

1
Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield S1 1WB, UK
2
School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, UK
*
Author to whom correspondence should be addressed.
Present address: School of Chemical Engineering, University of Birmingham, Birmingham B15 2TT, UK.
Chemosensors 2020, 8(3), 80; https://doi.org/10.3390/chemosensors8030080
Received: 9 July 2020 / Revised: 20 August 2020 / Accepted: 26 August 2020 / Published: 31 August 2020
(This article belongs to the Section Materials for Chemical Sensing)
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. View Full-Text
Keywords: gold nanoparticles; cysteamine; 3-Mercaptopropionic Acid; l-Selenocystine; functionalization; self-assembled monolayers; sensor applications gold nanoparticles; cysteamine; 3-Mercaptopropionic Acid; l-Selenocystine; functionalization; self-assembled monolayers; sensor applications
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MDPI and ACS Style

Sakellari, G.I.; Hondow, N.; Gardiner, P.H.E. Factors Influencing the Surface Functionalization of Citrate Stabilized Gold Nanoparticles with Cysteamine, 3-Mercaptopropionic Acid or l-Selenocystine for Sensor Applications. Chemosensors 2020, 8, 80. https://doi.org/10.3390/chemosensors8030080

AMA Style

Sakellari GI, Hondow N, Gardiner PHE. Factors Influencing the Surface Functionalization of Citrate Stabilized Gold Nanoparticles with Cysteamine, 3-Mercaptopropionic Acid or l-Selenocystine for Sensor Applications. Chemosensors. 2020; 8(3):80. https://doi.org/10.3390/chemosensors8030080

Chicago/Turabian Style

Sakellari, Georgia I., Nicole Hondow, and Philip H.E. Gardiner. 2020. "Factors Influencing the Surface Functionalization of Citrate Stabilized Gold Nanoparticles with Cysteamine, 3-Mercaptopropionic Acid or l-Selenocystine for Sensor Applications" Chemosensors 8, no. 3: 80. https://doi.org/10.3390/chemosensors8030080

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