%0 Journal Article
%A Welden, Rene
%A Gottschalk, Caspar
%A Madarevic, Ivan
%A Van Bael, Margriet J.
%A Iken, Heiko
%A Schubert, Jürgen
%A Schöning, Michael J.
%A Wagner, Patrick H.
%A Wagner, Torsten
%T Formation of controllable pH gradients inside microchannels by using light-addressable electrodes
%J Sensors and actuators / B
%V 346
%@ 0925-4005
%C Amsterdam [u.a.]
%I Elsevier Science
%M FZJ-2021-04862
%P 130422 -
%D 2021
%X Understanding the influence of the pH value towards microenvironments of bioanalytical systems, especiallyinside lab-on-a-chip or micro total analysis systems, is crucial for the success of experiments. Different approaches are known to control the pH value inside those microchannels and to tailor pH gradients. Nevertheless,the existing concepts often lack the possibility for a flexible adaption of these gradients. To overcome thislimitation, the present work reports on light-addressable electrodes (LAEs) as a tool to create pH gradients at themicro scale. Light-addressable electrodes are based on semiconductor materials in which electron-hole pairs aregenerated by illumination. These free charge carriers can trigger chemical reactions at the semiconductor-electrolyte interface, including the change of the pH value. For this purpose, we have designed LAEs based onglass/fluorine-doped tin oxide/titanium dioxide heterostructures. This work studies the influence of the appliedexternal potential, illumination brightness and illumination area on the maximum pH change and width of thepH gradient using a pH-sensitive fluorescent dye. Furthermore, we evaluate the correlation between the pHchange and electrical charge transfer. Finally, we provide an outlook towards tailoring complex pH gradientsinside microchannels.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000691819500003
%R 10.1016/j.snb.2021.130422
%U https://juser.fz-juelich.de/record/903138
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