Light-Addressable Potentiometric Sensor as a Sensing Element in Plug-Based Microfluidic Devices

Ko-Ichiro Miyamoto; Takuya Sato; Minami Abe; Torsten Wagner; Michael J Schöning; Tatsuo Yoshinobu

doi:10.3390/mi7070111

Light-Addressable Potentiometric Sensor as a Sensing Element in Plug-Based Microfluidic Devices

Micromachines (Basel). 2016 Jul 1;7(7):111. doi: 10.3390/mi7070111.

Authors

Ko-Ichiro Miyamoto¹, Takuya Sato², Minami Abe³, Torsten Wagner⁴, Michael J Schöning^{5

6}, Tatsuo Yoshinobu^{7

8}

Affiliations

¹ Department of Electronic Engineering, Tohoku University, 6-6-05 Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan. k-miya@ecei.tohoku.ac.jp.
² Department of Electronic Engineering, Tohoku University, 6-6-05 Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan. t.sato.tohoku@gmail.com.
³ Department of Electronic Engineering, Tohoku University, 6-6-05 Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan. minami.abe.1190@gmail.com.
⁴ Institute of Nano- and Biotechnologies, Aachen University of Applied Sciences, Heinrich-Mußmann-Str. 1, Jülich 52428, Germany. torsten.wagner@fh-aachen.de.
⁵ Institute of Nano- and Biotechnologies, Aachen University of Applied Sciences, Heinrich-Mußmann-Str. 1, Jülich 52428, Germany. schoening@fh-aachen.de.
⁶ Peter-Grünberg Institute (PGI-8), Research Centre Jülich, Jülich 52425, Germany. schoening@fh-aachen.de.
⁷ Department of Electronic Engineering, Tohoku University, 6-6-05 Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan. nov@ecei.tohoku.ac.jp.
⁸ Department of Biomedical Engineering, Tohoku University, 6-6-05 Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan. nov@ecei.tohoku.ac.jp.

Abstract

A plug-based microfluidic system based on the principle of the light-addressable potentiometric sensor (LAPS) is proposed. The LAPS is a semiconductor-based chemical sensor, which has a free addressability of the measurement point on the sensing surface. By combining a microfluidic device and LAPS, ion sensing can be performed anywhere inside the microfluidic channel. In this study, the sample solution to be measured was introduced into the channel in a form of a plug with a volume in the range of microliters. Taking advantage of the light-addressability, the position of the plug could be monitored and pneumatically controlled. With the developed system, the pH value of a plug with a volume down to 400 nL could be measured. As an example of plug-based operation, two plugs were merged in the channel, and the pH change was detected by differential measurement.

Keywords: chemical sensor; light-addressable potentiometric sensor; plug-based microfluidic device.