Fabrication of riboflavin electrochemical sensor based on homoadenine single-stranded DNA/molybdenum disulfide-graphene nanocomposite modified gold electrode

Very recently, the interest in layered transition metal chalcogenides, especially molybdenum disulfide (MoS2), has been growing as quickly as interest in two-dimensional graphene did a few years ago because they share many impressive physicochemical properties of graphene. For the first time, we herein attempted to exploit 32-mer homoadenine ssDNA oligonucleotides (A(32)) and graphene as an effective anchoring block for attachment to the layered MoS2 and the Au electrode, and then the MoS2 binding with the Au electrode was electrochemically reduced to form the reduced MoS2 (rMoS(2)). The morphology and electrochemistry of the obtained rMoS(2)-graphene/A(32)/Au electrode were characterized by various techniques such as scanning electron microscopy, energy-dispersive X-ray spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. To show the electrochemical sensing performance of the modified electrode, riboflavin was selected as model target. The results displayed that the riboflavin sensor with the use of differential pulse voltammetry possessed a wide linear range from 0.025 to 2.25 mu M, with a low detection limit of 20 nM. The sensor was then successfully employed for the detection of riboflavin in human urine samples. (C) 2014 Elsevier B.V. All rights reserved.