title: Solution chemistry of self-assembled graphene nanohybrids for high-performance flexible biosensors.
abstract: We report the preparation of free-standing flexible conductive reduced graphene oxide/Nafion (RGON) hybrid films by a solution chemistry that utilizes self-assembly and directional convective-assembly. The hydrophobic backbone of Nafion provided well-defined integrated structures, on micro- and macroscales, for the construction of hybrid materials through self-assembly, while the hydrophilic sulfonate groups enabled highly stable dispersibility ( approximately 0.5 mg/mL) and long-term stability (2 months) for graphene. The geometrically interlocked morphology of RGON produced a high degree of mechanical integrity in the hybrid films, while the interpenetrating network constructed favorable conduction pathways for charge transport. Importantly, the synergistic electrochemical characteristics of RGON were attributed to high conductivity (1176 S/m), facilitated electron transfer (ET), and low interfacial resistance. Consequently, RGON films obtained the excellent figure of merit as electrochemical biosensing platforms for organophosphate (OP) detection, that is, a sensitivity of 10.7 nA/microM, detection limit of 1.37 x 10(-7) M, and response time of <3 s. In addition, the reliability of RGON biosensors was confirmed by a fatigue test of 100 bending cycles. The strategy described here provides insight into the fabrication of graphene and hybrid nanomaterials from a material perspective, as well as the design of biosensor platforms for practical device applications.
authors.affiliation: Department of Chemical & Biomolecular Engineering, KAIST, Daejeon 305-701, Korea.
authors.forename: Bong Gill
authors.initials: BG
authors.lastname: Choi
authors.forename: Hoseok
authors.initials: H
authors.lastname: Park
authors.forename: Tae Jung
authors.initials: TJ
authors.lastname: Park
authors.forename: Min Ho
authors.initials: MH
authors.lastname: Yang
authors.forename: Joon Sung
authors.initials: JS
authors.lastname: Kim
authors.forename: Sung-Yeon
authors.initials: SY
authors.lastname: Jang
authors.forename: Nam Su
authors.initials: NS
authors.lastname: Heo
authors.forename: Sang Yup
authors.initials: SY
authors.lastname: Lee
authors.forename: Jing
authors.initials: J
authors.lastname: Kong
authors.forename: Won Hi
authors.initials: WH
authors.lastname: Hong
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002244:Carbon / Q000737:chemistry*; D002619:Chemical Warfare Agents / Q000737:chemistry; D004553:Electric Conductivity; D005465:Fluorocarbon Polymers / Q000737:chemistry*; D007306:Insecticides / Q000032:analysis; D049329:Nanostructures / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D010261:Paraoxon / Q000032:analysis; D012996:Solutions; D013997:Time Factors
chemical_list: D002619:Chemical Warfare Agents; D005465:Fluorocarbon Polymers; D007306:Insecticides; D010087:Oxides; D012996:Solutions; C040402:perfluorosulfonic acid; D002244:Carbon; D010261:Paraoxon