Nanostructured Fe3O4 satellite gold nanoparticles to improve biomolecular detection

作者：Ballesteros Camilo A S; Cancino Juliana^*; Marangoni Valeria S; Zucolotto Valtencir

来源：Sensors and Actuators B: Chemical , 2014, 198: 377-383.

DOI：10.1016/j.snb.2014.03.079

• Iron oxide/gold nanoparticle
• Core-shell
• Sensor
• Dopamine
• Layer-by-layer fabricationa

Fe3O4 satellite gold nanoparticles (Fe3O4@Au) have proved to be very useful in biomedical and technological applications because of their unique optical, magnetic, and catalytic properties. The electrocatalytic properties of Fe3O4@Au nanoparticles enable them to be used as mediator agents during the redox of electroactive species. In this study, Fe3O4@Au were synthesized in the presence of generation four polyamidoamine (PAMAM G4). The Fe3O4@Au nanoparticles were immobilized by layer-by-layer (LbL) technique to develop dopamine sensors by alternately depositing layers of Fe3O4@Au nanoparticles and poly(vinyl sulfonic acid) as polyanionic polymer onto an indium tin oxide electrode. The electrochemical performances of the indium tin oxide/poly(vinyl sulfonic acid) and indium tin oxide/gold nanoparticle/poly(vinyl sulfonic acid) electrodes were also investigated for comparison. The modified electrodes were characterized using ultraviolet-vis absorption spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction and cyclic voltammetry. The electrocatalytic properties of the iron oxide/gold nanoparticles configured throughout the indium tin oxide-iron oxide/gold/poly(vinyl sulfonic acid) architecture promoted a dopamine oxidation process at a potential of 0.30 V, which is lower compared with those observed for the other sensors. The dopamine sensor provided linear responses to dopamine in the 4-100 mu M range with detection limit and quantification values as 3.94 x 10(-8) M and 15.5 x 10(-8) M, respectively. Furthermore, the main interferents to dopamine detection were ascorbic and uric acids, whose cyclic voltammograms showed oxidation peaks that, were displaced by 0.2 and 0.39 V in their respective binary mixtures with dopamine. The immobilized iron oxide/gold nanoparticles in the layer-by- layer-fabricated films exhibited an efficient electron transfer, which could be useful when such films are combined with other conjugated materials to detect electroactive species that are highly relevant inmedical applications.

• 出版日期2014-7