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Covalent Immobilization of Gold Nanoparticles on Graphene

Hossain, M. Zakir, Shimizu, Natsuhiko
Journal of physical chemistry 2019 v.123 no.6 pp. 3512-3516
biochemical compounds, borohydrides, chemical bonding, graphene, nanogold, silicon carbide
The combination of the extraordinary electrical and optoelectrical properties of graphene and the binding potential of gold nanoparticles (AuNPs) with various small molecules and biological targets can aid in the development of ultrasensitive chemical and biological sensors. In this study, we carried out the covalent immobilization of AuNPs on the surface of graphene and investigated their further reaction with two target molecules. In the first step, epitaxial graphene (EG) on SiC was functionalized with −SH groups through the in situ primary amine diazotization reaction. The −SH-functionalized EG/SiC was then treated with HAuCl₄ during the synthesis of AuNPs via the NaBH₄ reduction process at 80 °C. The HAuCl₄ treatment resulted in the decoration of graphene with covalently bonded (through −S–Au bonding) AuNPs (25–70 nm). The immobilized AuNPs further reacted with other reactive molecules such as hexanedithiol (HSC₆H₁₂SH) and pentachlorobenzenethiol (Cl₅C₆SH). Hence, the results demonstrated that AuNPs can be effectively immobilized on the surface of SH-functionalized EG/SiC, and the resulting assembly can be used for capturing specific biomolecules.