High-speed imaging of 2-D ionic diffusion using a 16x16-pixel CMOS ISFET array on the microfluidic scale

Shields, P., Nemeth, B., Green, R. , Riehle, M. and Cumming, D.R.S. (2012) High-speed imaging of 2-D ionic diffusion using a 16x16-pixel CMOS ISFET array on the microfluidic scale. IEEE Sensors Journal, 12(9), pp. 2744-2749. (doi:10.1109/JSEN.2012.2200249)

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Abstract

We present an electrochemical high-speed measurement for direct observation of the mixing of ions in solution over a sensor surface. The method is applied to the determination of time-varying mixing and diffusion rates in microfluidic systems. The system generates high-speed videos of the analytes under investigation as they mix, without the need for any preliminary staining or labeling and has a pixel-to-pixel pitch of 14 μm. We demonstrate ion displacement phenomena on the surface of a Si3N4-passivated complementary metal oxide semiconductor ion-sensitive field effect transistor array device and also monitor the pH change induced by the addition of sulfuric acid to normal saline. These chemical videos are recorded with a frame rate of up to 333 frames/s. By evaluating the time-varying change in ionic concentrations across the surface of the chip, we calculate time varying estimates of diffusivity coefficient values for the mixing analytes.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Green, Dr Richard and Nemeth, Mr Balazs and Cumming, Professor David and Riehle, Dr Mathis
Authors: Shields, P., Nemeth, B., Green, R., Riehle, M., and Cumming, D.R.S.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:IEEE Sensors Journal
ISSN:1530-437X
ISSN (Online):1558-1748
Published Online:24 July 2012

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