Histidine-functionalized graphene quantum dot-graphene micro-aerogel based voltammetric sensing of dopamine

• Published in: Sensors and actuators. B, Chemical Vol. 250; pp. 372 - 382
• Main Authors: Ruiyi, Li, Sili, Qing, Zhangyi, Li, Ling, Liu, Zaijun, Li
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.10.2017; Elsevier Science Ltd
• Subjects: Aerogels; Brain; Catalysis; Catalytic activity; Citric acid; Differential pulse voltammetry; Dispersion; Dopamine; Electrodes; Electronic properties; Energy storage; Graphene; Histidine; Hybrid; Hydrazines; Light emitting diodes; Pickering emulsion; Pyrolysis; Quantum dots; Sensors; Signal to noise ratio; Soft template method; Structural stability; Synthesis; Toluene; Soft template method; Hybrid; Synthesis; Pickering emulsion; Differential pulse voltammetry
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2017.05.001

The article reports the synthesis of Histidine-functionalized graphene quantum dot-graphene micro-aerogel. The biosensor based on the hybrid exhibits the advantage of sensitivity, reproducibility and stability. The study also opens a window on the electronic properties of graphene aerogel and graphene quantum dots as well their hybrids to meet needs of further applications as the nanoelectronics in sensors, catalysis and energy storage and conversion devices. [Display omitted] •We report synthesis of histidine-functionalized graphene quantum dot-graphene micro-aerogel.•The micro-aerogel can be directly dispersed in ethanol for the sensor preparation.•The unique structure creates excellent electrocatalytic activity and structural stability.•The sensor based on the hybrid exhibits ultrasensitive electrochemical response to dopamine.•The study offers a promising approach for fabrication of functional graphene micro-aerogel. Histidine-functionalized graphene quantum dots (His-GQDs) made via thermal pyrolysis of citric acid and histidine are combined with Zn2+ ions to form Zn-His-GQD complex. The complex was employed as the solid surfactant for stabilizing toluene-in-graphene oxide aqueous dispersion emulsion. The graphene oxide in the Pickering emulsion was slowly reduced by addition of hydrazine hydrate and leads to the formation of graphene micro-gel. The micro-gel was treated by freeze-drying, acid washing and thermal annealing to obtain His-GQD-graphene micro-aerogel (His-GQD-GMA). The as-prepared hybrid offers a three-dimensional architecture with well-defined porous structures, in which the His-GQDs were well dispersed and fixed on the graphene sheets. The all-carbon hybrid provides excellent electron/ion conductivity, electro-catalytic activity and structural stability. The sensor based on the His-GQD-GMA exhibits ultrasensitive electrochemical response to dopamine. Its differential pulse voltammetric signal linearly increases with the increase of dopamine concentration in the range from 1.0×10−9M to 8.0×10−5M with the detection limit of 2.9×10−10M (at a S/N ratio of 3). The sensitivity is much better than that of the reported graphene sensors for dopamine. The analytical method has been successfully applied in the detection of dopamine in rat brain. The study also opens a window on the electronic properties of graphene aerogel and graphene quantum dots as well their hybrids to meet needs of further applications in sensors, catalysis and energy storage and conversion devices.