title: Defect-Mediated Molecular Interaction and Charge Transfer in Graphene Mesh-Glucose Sensors.
abstract: We report the role of defects in enzymatic graphene field-effect transistor sensors by introducing engineered defects in graphene channels. Compared with conventional graphene sensors (Gr sensors), graphene mesh sensors (GM sensors), with an array of circular holes, initially exhibited a higher irreversible response to glucose, involving strong chemisorption to edge defects. However, after immobilization of glucose oxidase, the irreversibility of the responses was substantially diminished, without any reduction in the sensitivity of the GM sensors (i.e., -0.53 mV/mM for the GM sensor vs -0.37 mV/mM for Gr sensor). Furthermore, multiple cycle operation led to rapid sensing and improved the reversibility of GM sensors. In addition, control tests with sensors containing a linker showed that sensitivity was increased in Gr sensors but decreased in GM sensors. Our findings indicate that edge defects can be used to replace linkers for immobilization of glucose oxidase and improve charge transfer across glucose oxidase-graphene interfaces.
authors.affiliation: Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea.
authors.forename: Sun Sang
authors.initials: SS
authors.lastname: Kwon
authors.affiliation: Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea.
authors.forename: Jae Hyeok
authors.initials: JH
authors.lastname: Shin
authors.affiliation: Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors.forename: Jonghyun
authors.initials: J
authors.lastname: Choi
authors.affiliation: Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors.forename: SungWoo
authors.identifier: http://orcid.org/0000-0002-9719-7203
authors.initials: S
authors.lastname: Nam
authors.affiliation: Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Korea.
authors.forename: Won Il
authors.identifier: http://orcid.org/0000-0001-8312-4815
authors.initials: WI
authors.lastname: Park
keywords: edge functionalization; enzymatic sensor; graphene; graphene mesh; multiple cycle operation