Dielectrophoretic characterization of micro-organisms and other particles

[54] DIELECTROPHORETIC
CHARACTERIZATION OF
MICRO-ORGANISMS AND OTHER
PARTICLES

[75] Inventors: Walter B. Betts, Wilberfoss; Jeremy J. Hawkes, Fishergate, both of England

[73] Assignee: British Technology Group Limited, London, England

[21] Appl. No.: 53,326

[22] Filed: Apr. 27,1993

Related U.S. Application Data

[63] Continuation of Ser. No. 730,888, Jul. 22, 1991, abandoned.

[30] Foreign Application Priority Data

Nov. 27, 1989 [GB] United Kingdom 8926781.9

[51] Int. C1.5 G01N 27/26; G01N 27/447

[52] U.S. CI 204/183.1; 204/180.1;

204/299 R

[58] Field of Search 204/299 R, 180.1, 183.1,

204/183.3

[56] References Cited

U.S. PATENT DOCUMENTS

4,326,934 4/1982 Pohl 204/183.1

4,476,004 10/1984 Pohl 204/299 R

4,578,167 3/1986 Schoner 204/183.1

OTHER PUBLICATIONS

Julian P. H. Burt et al. "An optical dielectrophoresis spectrometer for low-frequency measurements on col

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.

6 Claims, 3 Drawing Sheets