TY  - JOUR
AU  - Welden, Rene
AU  - Gottschalk, Caspar
AU  - Madarevic, Ivan
AU  - Van Bael, Margriet J.
AU  - Iken, Heiko
AU  - Schubert, Jürgen
AU  - Schöning, Michael J.
AU  - Wagner, Patrick H.
AU  - Wagner, Torsten
TI  - Formation of controllable pH gradients inside microchannels by using light-addressable electrodes
JO  - Sensors and actuators  / B
VL  - 346
SN  - 0925-4005
CY  - Amsterdam [u.a.]
PB  - Elsevier Science
M1  - FZJ-2021-04862
SP  - 130422 -
PY  - 2021
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000691819500003
DO  - DOI:10.1016/j.snb.2021.130422
UR  - https://juser.fz-juelich.de/record/903138
ER  -