Particle Electrophoresis in Closed-both-end Capillary and Likely Charged Particle Aggregation Induced by AC Electric Field


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Electroosmosis flow (EOF) is a critical issue in electrophoresis separation techniques. The magnitude of EOF problems and difficult level of its solution are demonstrated by 33 issued US Patents on different methods to suppress or eliminate EOF in CE since 1987. These patents focused on masking surface charges in fused silica capillaries and have met with limited success. So, there is a great need to change dealing with EOF issues. We present a very simple idea. We just close two ends of a capillary and run AC or DC electrophoresis with water-based suspensions. In the DC CE, apparent particle electrophoresis mobility in the closed-both-end capillary has complex relations with the electric field. We get a better understanding of interactions among EOF, fluid bulk flow and particle by analyzing particle velocity and velocity distribution. The information will lead to a new technique to deal with EOF. In the AC CE, one key observation is that the likely-charged particles are induced to aggregate in some frequency band. The finding provides clues to understanding electrostatic behaviors of DNA and proteins in aqueous liquids. We are developing one approximation analytic method to understand attractive interactions among likely-charged particles in an AC electric field.

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Journal: TechConnect Briefs
Volume: 3, Technical Proceedings of the 2007 NSTI Nanotechnology Conference and Trade Show, Volume 3
Published: May 20, 2007
Pages: 433 - 436
Industry sector: Sensors, MEMS, Electronics
Topic: Micro & Bio Fluidics, Lab-on-Chip
ISBN: 1-4200-6184-4