TY  - JOUR
A1  - Miyamoto, Ko-ichiro
A1  - Ichimura, Hiroki
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Yoshinobu, Tatsuo
T1  - Chemical imaging of the concentration profile of ion diffusion in a microfluidic channel
JF  - Sensors and actuators. B: Chemical
N2  - The chemical imaging sensor is a device to visualize the spatial distribution of chemical species based on the principle of LAPS (light-addressable potentiometric sensor), which is a field-effect chemical sensor based on semiconductor. In this study, the chemical imaging sensor has been applied to investigate the ion profile of laminar flows in a microfluidic channel. The chemical images (pH maps) were collected in a Y-shaped microfluidic channel while injecting HCl and NaCl solutions into two branches. From the chemical images, it was clearly observed that the injected solutions formed laminar flows in the channel. In addition, ion diffusion across the laminar flows was observed, and the diffusion coefficient could be derived by fitting the pH profiles to the Fick's equation.
Y1  - 2013
U6  - http://dx.doi.org/10.1016/j.snb.2013.04.057
SN  - 1873-3077 (E-Journal); 0925-4005 (Print)
N1  - Part of special issue "Selected Papers from the 26th European Conference on Solid-State Transducers"
VL  - 189
SP  - 240
EP  - 245
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Miyamoto, Ko-ichiro
A1  - Hirayama, Yuji
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
A1  - Yoshinobu, Tatsuo
T1  - Visualization of enzymatic reaction in a microfluidic channel using chemical imaging sensor
JF  - Electrochimica acta
Y1  - 2013
SN  - 1873-3859 (E-Journal); 0013-4686 (Print)
SP  - Publ. online
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Itabashi, Akinori
A1  - Kosaka, Naoki
A1  - Miyamoto, Ko-ichiro
A1  - Wagner, Torsten
A1  - Schöning, Michael Josef
T1  - High-speed chemical imaging system based on front-side-illuminated LAPS
JF  - Sensors and actuators B: Chemical
N2  - The chemical imaging sensor is a semiconductor-based chemical sensor that can visualize the spatial distribution of specific ions on the sensing surface. The conventional chemical imaging system based on the light-addressable potentiometric sensor (LAPS), however, required a long time to obtain a chemical image, due to the slow mechanical scan of a single light beam. For high-speed imaging, a plurality of light beams modulated at different frequencies can be employed to measure the ion concentrations simultaneously at different locations on the sensor plate by frequency division multiplex (FDM). However, the conventional measurement geometry of back-side illumination limited the bandwidth of the modulation frequency required for FDM measurement, because of the low-pass filtering characteristics of carrier diffusion in the Si substrate. In this study, a high-speed chemical imaging system based on front-side-illuminated LAPS was developed, which achieved high-speed spatiotemporal recording of pH change at a rate of 70 frames per second.
Y1  - 2013
U6  - http://dx.doi.org/10.1016/j.snb.2013.03.016
SN  - 1873-3077
VL  - 182
SP  - 315
EP  - 321
PB  - Elsevier
CY  - Amsterdam
ER  -