title: Microfluidic push-pull probe for scanning electrochemical microscopy.
abstract: This paper presents a microfluidic push-pull probe for scanning electrochemical microscopy (SECM) consisting of a working microelectrode, an integrated counter/reference electrode and two microchannels for pushing and pulling an electrolyte solution to and away from a substrate. With such a configuration, a droplet of a permanently renewed redox mediator solution is maintained just at the probe tip to carry out SECM measurements on initially dry substrates or in microenvironments. For SECM imaging purposes, the probe fabricated in a soft polymer material is used in a contact regime. SECM images of various gold-on-glass samples demonstrate the proof-of-concept of a push-pull probe for local surface activity characterization with high spatial resolution even on vertically oriented substrates. Finite element computations were performed to guide the improvement of the probe sensitivity.
authors.affiliation: Laboratoire d'Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Momotenko
authors.forename: Fernando
authors.initials: F
authors.lastname: Cortes-Salazar
authors.forename: Andreas
authors.initials: A
authors.lastname: Lesch
authors.forename: Gunther
authors.initials: G
authors.lastname: Wittstock
authors.forename: Hubert H
authors.initials: HH
authors.lastname: Girault
mesh_terms: D004563:Electrochemistry / Q000379:methods*; D020342:Finite Element Analysis; D008839:Microelectrodes; D044085:Microfluidics; D008855:Microscopy, Electron, Scanning / Q000379:methods*