Dielectrophoresis-based particle sensor using nanoelectrode arrays

US7635420B1 · kind B1 · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• Jun Li · Norwood, US
• Alan M. Cassell · Campbell, US
• Prabhu U. Arumugam · Ruston, US

Key dates

• Filing date: Nov 21, 2006
• Grant date: Dec 22, 2009
• Expiry date: May 6, 2028

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B03C5/026
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

A method for concentrating or partly separating particles of a selected species from a liquid or fluid containing these particles and flowing in a channel, and for determining if the selected species particle is present in the liquid or fluid. A time varying electrical field E, having a root-mean-square intensity E2rms with a non-zero gradient in a direction transverse to the liquid or fluid flow direction, is produced by a nanostructure electrode array, with a very high magnitude gradient near exposed electrode tips. A dielectrophoresis force causes the selected particles to accumulate near the electrode tips, if the medium and selected particles have substantially different dielectric constants. An insulating material surrounds most of each of the nanostructure electrodes, and a region of the insulating material surface is functionalized to promote attachment of the selected species particles to the surface. An electrical property value Z(meas) is measured at the functionalized surface and is compared with a reference value Z(ref) to determine if the selected species particles are attached to the functionalized surface.