title: Three-dimensional graphene micropillar based electrochemical sensor for phenol detection.
abstract: A three-dimensional (3D) graphene incorporated electrochemical sensor was constructed for sensitive enzyme based phenol detection. To form the 3D graphene structure, polydimethylsiloxane (PDMS) micropillars were fabricated in the microchannel by using a conventional photolithography and the surface was modified with 3-aminopropyltriethoxysilane. Then, the negatively charged graphene oxide sheets were electrostatically adsorbed on the PDMS micropillar surface, and reduced in the hydrazine vapor. The resultant 3D graphene film provides a conductive working electrode as well as an enzyme-mediated sensor with a large surface area. After bonded with an electrode patterned glass wafer, the 3D graphene based electrochemical sensor was produced. Using the 3D graphene as a working electrode, an excellent electron transfer property was demonstrated by cyclic voltammetry measurement in an electrolyte solution containing 1mM K3Fe(CN)6 and 0.1 M KCl. To utilize the 3D graphene as an enzyme sensor, tyrosinase enzymes were immobilized on the surface of the graphene micropillar, and the target phenol was injected in the microchannel. The enzyme catalytic reaction process was monitored by amperometric responses and the limit of detection for phenol was obtained as 50 nM, thereby suggesting that the 3D graphene micropillar structure enhances the enzyme biosensing capability not only by increasing the surface area for enzyme immobilization, but also by the superlative graphene conductivity property.
authors.affiliation: Department of Chemical and Biomolecular Engineering (BK21 Program), Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.forename: Yunxian
authors.initials: Y
authors.lastname: Piao
authors.forename: Jong Seob
authors.initials: JS
authors.lastname: Choi
authors.forename: Tae Seok
authors.initials: TS
authors.lastname: Seo
mesh_terms: D000363:Agaricales / Q000201:enzymology; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004800:Enzymes, Immobilized / Q000378:metabolism; D004867:Equipment Design; D006108:Graphite / Q000737:chemistry*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D014442:Monophenol Monooxygenase / Q000378:metabolism; D019800:Phenol / Q000032:analysis* / Q000378:metabolism
chemical_list: D004129:Dimethylpolysiloxanes; D004800:Enzymes, Immobilized; D019800:Phenol; C013830:baysilon; D006108:Graphite; D014442:Monophenol Monooxygenase
keywords: Electrochemical sensor; Enzyme; Graphene; Micropilar; Phenol detection