title: Compact Nanowire Sensors Probe Microdroplets.
abstract: The conjunction of miniature nanosensors and droplet-based microfluidic systems conceptually opens a new route toward sensitive, optics-less analysis of biochemical processes with high throughput, where a single device can be employed for probing of thousands of independent reactors. Here we combine droplet microfluidics with the compact silicon nanowire based field effect transistor (SiNW FET) for in-flow electrical detection of aqueous droplets one by one. We chemically probe the content of numerous (∼10(4)) droplets as independent events and resolve the pH values and ionic strengths of the encapsulated solution, resulting in a change of the source-drain current ISD through the nanowires. Further, we discuss the specificities of emulsion sensing using ion sensitive FETs and study the effect of droplet sizes with respect to the sensor area, as well as its role on the ability to sense the interior of the aqueous reservoir. Finally, we demonstrate the capability of the novel droplets based nanowire platform for bioassay applications and carry out a glucose oxidase (GOx) enzymatic test for glucose detection, providing also the reference readout with an integrated parallel optical detector.
authors.affiliation: Max Bergmann Center of Biomaterials and Institute for Materials Science, Dresden University of Technology , Budapesterstrasse 27, 01069 Dresden, Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Schütt
authors.affiliation: Max Bergmann Center of Biomaterials and Institute for Materials Science, Dresden University of Technology , Budapesterstrasse 27, 01069 Dresden, Germany.|Center for Advancing Electronics Dresden, 01062 Dresden, Germany.
authors.forename: Bergoi
authors.initials: B
authors.lastname: Ibarlucea
authors.affiliation: Max Bergmann Center of Biomaterials and Institute for Materials Science, Dresden University of Technology , Budapesterstrasse 27, 01069 Dresden, Germany.|Center for Advancing Electronics Dresden, 01062 Dresden, Germany.
authors.forename: Rico
authors.initials: R
authors.lastname: Illing
authors.affiliation: Max Bergmann Center of Biomaterials and Institute for Materials Science, Dresden University of Technology , Budapesterstrasse 27, 01069 Dresden, Germany.|Center for Advancing Electronics Dresden, 01062 Dresden, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Zörgiebel
authors.affiliation: Max Bergmann Center of Biomaterials and Institute for Materials Science, Dresden University of Technology , Budapesterstrasse 27, 01069 Dresden, Germany.|Center for Advancing Electronics Dresden, 01062 Dresden, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Pregl
authors.affiliation: Max Bergmann Center of Biomaterials and Institute for Materials Science, Dresden University of Technology , Budapesterstrasse 27, 01069 Dresden, Germany.
authors.forename: Daijiro
authors.initials: D
authors.lastname: Nozaki
authors.affiliation: Center for Advancing Electronics Dresden, 01062 Dresden, Germany.|Namlab GmbH, Nöthnitzerstraße 64, 01187 Dresden, Germany.
authors.forename: Walter M
authors.initials: WM
authors.lastname: Weber
authors.affiliation: Center for Advancing Electronics Dresden, 01062 Dresden, Germany.|Namlab GmbH, Nöthnitzerstraße 64, 01187 Dresden, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mikolajick
authors.affiliation: Max Bergmann Center of Biomaterials and Institute for Materials Science, Dresden University of Technology , Budapesterstrasse 27, 01069 Dresden, Germany.|Center for Advancing Electronics Dresden, 01062 Dresden, Germany.
authors.forename: Larysa
authors.initials: L
authors.lastname: Baraban
authors.affiliation: Max Bergmann Center of Biomaterials and Institute for Materials Science, Dresden University of Technology , Budapesterstrasse 27, 01069 Dresden, Germany.|Center for Advancing Electronics Dresden, 01062 Dresden, Germany.
authors.forename: Gianaurelio
authors.initials: G
authors.lastname: Cuniberti
keywords: Silicon nanowires FET; droplet-based microfluidics; glucose assay; nanosensor; point-of-care diagnostics