Facile synthesis of Au@α-Fe2O3@RGO ternary nanocomposites for enhanced electrochemical sensing of caffeic acid toward biomedical applications

Demonstrated herewith is a novel eco-friendly Au@si-Fe2O3@RGO ternary nanocomposites using chlorophyll as reductants and stabilizers. Systematic characterizations studies confirm Au and alpha-Fe2O3 nanoparticles are uniformly decorated on the surfaces of reduced graphene oxide (RGO) nanosheets. As a proof-of-concept, the developed Au@alpha-Fe2O3@RGO ternary nanocomposites were coated on a glass carbon electrode (GCE) and evaluated for electrochemical detection of caffeic acid. The electrochemical mechanism involves the synergistic electrocatalytic activity of Au and alpha-Fe2O3 towards caffeic acid oxidation, with the RGO serving as an efficient electron shuttling mediator-enhancing the sensor performance. The Au@alpha-Fe2O3@RGO modified GCE caffeic acid sensor exhibited a wide linear response range of 19-1869 mu M, sensitivity of 315 mu A mu M-1 cm(-2), and a detection limit of 0.098 mu M at very low potential of 0.21 V. This ternary nanocomposite provides high catalytic performance as well as excellent selectivity toward caffeic acid. To demonstrate real life application of the Fe2O3@RGO modified GCE caffeic acid sensor, caffeic acid in a coffee sample was measured. The alpha-Fe2O3, Au-NPs, and conductive graphene sheets composites, result in a highly catalytic and stable electrode system, with no pulverization problems. As such, it is demonstrated herewith that the Fe2O3@RGO ternary nanocomposite electrode is rapid, highly stable, and sensitive, with promised for utilization in fabrication of other multifarious biosensors. (C) 2018 Elsevier B.V. All rights reserved.