title: Electrochemical push-pull probe: from scanning electrochemical microscopy to multimodal altering of cell microenvironment.
abstract: To understand biological processes at the cellular level, a general approach is to alter the cells' environment and to study their chemical responses. Herein, we present the implementation of an electrochemical push-pull probe, which combines a microfluidic system with a microelectrode, as a tool for locally altering the microenvironment of few adherent living cells by working in two different perturbation modes, namely electrochemical (i.e., electrochemical generation of a chemical effector compound) and microfluidic (i.e., infusion of a chemical effector compound from the pushing microchannel, while simultaneously aspirating it through the pulling channel, thereby focusing the flow between the channels). The effect of several parameters such as flow rate, working distance, and probe inclination angle on the affected area of adherently growing cells was investigated both theoretically and experimentally. As a proof of concept, localized fluorescent labeling and pH changes were purposely introduced to validate the probe as a tool for studying adherent cancer cells through the control over the chemical composition of the extracellular space with high spatiotemporal resolution. A very good agreement between experimental and simulated results showed that the electrochemical perturbation mode enables to affect precisely only a few living cells localized in a high-density cell culture.
authors.affiliation: †Laboratoire d'Electrochimie Physique et Analytique, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Bondarenko
authors.affiliation: †Laboratoire d'Electrochimie Physique et Analytique, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Fernando
authors.initials: F
authors.lastname: Cortés-Salazar
authors.affiliation: ‡International Centre of Biodynamics, 1B Intrarea Portocalelor Street, 060101 Bucharest, Romania.
authors.forename: Mihaela
authors.initials: M
authors.lastname: Gheorghiu
authors.affiliation: ‡International Centre of Biodynamics, 1B Intrarea Portocalelor Street, 060101 Bucharest, Romania.
authors.forename: Szilveszter
authors.initials: S
authors.lastname: Gáspár
authors.affiliation: †Laboratoire d'Electrochimie Physique et Analytique, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Momotenko
authors.affiliation: ‡International Centre of Biodynamics, 1B Intrarea Portocalelor Street, 060101 Bucharest, Romania.|§Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, 050095 Bucharest, Romania.
authors.forename: Luciana
authors.initials: L
authors.lastname: Stanica
authors.affiliation: †Laboratoire d'Electrochimie Physique et Analytique, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Lesch
authors.affiliation: ‡International Centre of Biodynamics, 1B Intrarea Portocalelor Street, 060101 Bucharest, Romania.|§Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, 050095 Bucharest, Romania.
authors.forename: Eugen
authors.initials: E
authors.lastname: Gheorghiu
authors.affiliation: †Laboratoire d'Electrochimie Physique et Analytique, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Hubert H
authors.initials: HH
authors.lastname: Girault
mesh_terms: D060833:Cellular Microenvironment; D055664:Electrochemical Techniques / Q000295:instrumentation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008839:Microelectrodes; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation; D014407:Tumor Cells, Cultured