US 5,344,535 A · Dielectrophoretic characterization of micro-organisms and other particles

Abstract

Dielectrophoretic collection rates of micro-organisms or other animate or inanimate dielectrically polarizable particles in suspension in a fluid are established by flowing the suspension past electrodes energized to produce a non-uniform alternating electric field in the suspension, terminating the energization of the electrodes after a predetermined time to release particles collected from the suspension, and, downstream of the electrodes, measuring the pulse of released particles as a measure of the rate of particle collection during energization of the electrodes. Repeated measurements at different field frequencies enable a collection-rate spectrum to be established and the particles under examination to be characterized or identified by reference to known spectra of known particles.

Claims6

Dependent claims

Apparatus for establishing dielectrophoretic collection rates for particles in a fluid suspension, said apparatus comprising:

a chamber for said fluid suspension, said chamber having an inlet and an outlet;
an electrode system comprising closely spaced interdigitated electrodes for influencing said fluid suspension within said chamber;
means for applying an alternating voltage between said interdigitated electrodes of said electrode system and thereby establishing in said fluid suspension in the immediate vicinity of said electrodes a spatially non-uniform alternating electric field thereby to induce dielectrophoretic collection adjacent said electrodes of electrically polarizable particles suspended in said fluid suspension;
means for producing fluid flow of said fluid suspension through said chamber;
and
means for measuring particle concentration at a measuring region within said chamber, said inlet and outlet being so disposed that fluid suspension flowing through said chamber from said inlet to said outlet flows past said electrode system and immediately thereafter past said measuring region within said chamber.

3 more elements

A method of establishing dielectrophoretic collection rates for dielectrically polarizable particles in a fluid suspension, said method comprising the steps of:

causing a fluid suspension to flow in a chamber past an electrode structure;
energizing said electrode structure for a predetermined time interval with an alternating voltage at a preselected frequency and thereby establishing in said flowing fluid suspension a spatially non-uniform alternating electrical field and inducing dielectrophoretic collection, adjacent said electrode structure, of dielectrically polarizable particles suspended in said fluid suspension;
thereafter terminating the energizing of said electrode structure and thereby releasing particles collected adjacent thereto as a localized pulse of increased particle concentration in the flowing fluid suspension;
and
measuring said pulse of increased particle concentration at a measuring region located within said chamber and immediately downstream of said electrode structure.

2 more elements

Dependencies are inferred from the claim text.

Dielectrophoretic characterization of micro-organisms and other particles

Life of this patent

Dielectrophoretic characterization of micro-organisms and other particles

Life of this patent

Abstract

Claims6