FITC/PEG Functionalized Nanographene Oxide/Gold Nanocomposites Enable Efficient Response to Dopamine

Abstract Dopamine (DA) plays a crucial role in the regulation of human bodily functions and metabolism. It is necessary to detect and then to regulate DA levels for health maintenance. Electrochemical sensors have intrinsic advantages in DA determination, especially for metal nanoparticles‐based sensors with excellent physicochemical properties and efficient activity. In this article, AuNPs located on functional nanographene oxide (NGO) are fabricated for DA detection. As the facial platform, NGO has large surface areas to maintain AuNPs well disperse and provided enough carboxyls and epoxy groups for conjugating with poly(ethylene glycol) (PEG) and thiol active site. Functional biological fluorescence dye (FITC) is also introduced to this NGO platform. With stepwise functionalization, NGO is reconstructed as an optimal foundation for AuNPs presenting the inherent physicochemical properties. Finally, AuNPs are in‐situ grown on the platform by reduction of HAuCl₄ under mild conditions, i.e., AuNPs@SH‐NGO‐PEG‐FITC. In the detection of DA levels, AuNPs/NGO nanocomposites are coated on a glassy carbon electrode (GCE). Relying on corresponding cyclic voltammetric curves and typical ready‐state amperometric curves, it is informed that GCE/AuNPs@SH‐NGO‐PEG‐FITC can be employed in the electrochemical detection of DA levels. It is foreseen that efficient sensors and methods for DA determination with fluorescence tracers are provided.