Apparatus for separating by dielectrophoresis

• US 5,814,200 A
• Filed: 09/26/1995
• Issued: 09/29/1998
• Est. Priority Date: 03/31/1993
• Status: Expired due to Term

• Current Assignee: BTG International Limited (Boston Scientific Corporation)
• Original Assignee: British Technology Group Ltd.
• Inventors: Markx, Gerardus Hendricus, Pethig, Ronald
• Primary Examiner(s): Warden, Robert J.
• Assistant Examiner(s): STARSIAK, JOHN S
• Application Number:
  US08/530,131
• Time in Patent Office: 1,099 Days
• Field of Search: 204/547, 204/643, 209/127.1, 209/127.4
• US Class Current: 204/547
• CPC Class Codes: B03C 5/005 Dielectrophoresis, i.e. dielectric particles migrating towards the region of highest field strength B03C5/02 takes precedence; electrophoresis B01D57/02
• CPC Class Codes: B03C 5/026 using open-gradient differential dielectric separation, i.e. using electrodes of special shapes for non-uniform field creation, e.g. Fluid Integrated Circuit [FIC]

Abstract

The invention relates to a separator, which is particularly useful for separating cellular matter. The separator utilizes the phenomenon known as dielectrophoresis (DEP).

A DEP force effects a particle suspended in a medium. The particle experiences a force in an alternating electric field. The force is proportional to, amongst other things, the electrical properties of the supporting medium and the particle and the frequency of the electric field.

The separator, of the present invention, comprises a chamber (10) and a plurality of electrodes (12) disposed in the chamber (10).

An electric field established across electrodes subjects some of the particles to a stronger force than others such that they are confined within the chamber. Particles which are not confined are removed from the chamber by the supporting medium which is preferably urged through the chamber. Valves (101 and 202) are provided on exhausts of the chamber.

The invention is able to separate two different particles continuously.

Claims

1. An apparatus for separating first particles and second particles from a fluid supporting said first particles and said second particles, said apparatus comprising:

a housing forming a chamber, said housing having formed thereon an inlet, a first outlet, and a second outlet, said inlet and said first and said second outlets communicating with sald chamber;

a first electrode array and a second electrode array disposed within said chamber formed by said housing;

a fluid flow system supplying said fluid to said Inlet and removing said fluid from said first and said second outlets, thereby operating a fluid flow within said chamber;

frequenoy generating means connected to said first and said second electrode arrays for establishing a dielectrophoretic field between said first and said second electrode arrays to cause a first resultant force to be experienced by said first particles; and

control means for controlling said frequency generating means and said fluid flow system to remove said fluid from said first outlet while said first resultant force is experienced by said first particles, said control means including means to change said dielectrophoretic field to cause a second resultant force to be experienced by said second particles.

2. An apparatus acoording to claim 1, wherein said fluid flow system includes:

a conduit forming a fluid carrying passage, said conduit being coupled to said housing via said inlet; and

a selectively operable pressure source coupled to said conduit so as to provide said fluid to said inlet via said conduit.

3. An apparatus according to claim 1, wherein said fluid flow system further comprises:

a second conduit coupled to said housing via said first outlet;

a third couduit coupled to said housing via said second outlet; and

at least one valve disposed in one of said second conduit and said third conduit.

4. An apparatus according to any of claims 1, 2 or 3, wherein:

said fluid flow system further comprises a gravity feed.

5. An apparatus according to any of claims 1, 2 or 3, wherein:

said fluid flow system further comnpries a pump.

6. An apparatus according to claim 2, wherein said fluid flow system further comprises:

a second conduit forming a first fluid carrying passage coupled to said housing via said first outlet;

a third conduit forming a second fluid carrying passage coupled to said housing via said second outlet;

at least one valve disposed in one of said second conduit and said third conduit,

wherein said control means includes a microprocessor adapted to activate said dielectrophoretlo field, said at least one valve, and said pressure source in synchronism.

7. An apparatus according to claim 2, wherein:

each of said first and said second electrode arrays comprises sub-groups of electrodes, and

said control means controls said frequency generating means to cause said sub-groups of said first electrode array and said sub-groups of said second electrode array to be actuated in a cyclic manner.

8. An apparatus according to claim 1, further comprising:

means for varying a potential difference between adjacent electrodes of said first electrode army and said second electrode array.

9. An apparatus according to claim 1, further comprising:

means for varying a frequency of voltage applied between adjacent electrodes of said first electrode array and said second electrode array.

10. An apparatus according to claim 1, wherein:

said first electrode array and said second electrode array are interdigitated;

castellated electrodes.

11. An apparatus according to claim 1, wherein:

one of said first particles and said second particles is live cellular matter, and the other of said first particles and said second particles is dead cellular matter, and

said apparatus is arranged to separate said live cellular matter from said dead cellular matter.

12. An apparatus according to claim 1, wherein:

at least one of said first electrode array and said second electrode array includes;

an electrical contact for connection to an electrical energy source having a polarity which is controlled to change, and

a surface adapted for use in said chamber.

13. An apparatus according to claim 1, wherein:

at least one of said first electrode aray and said second electrode array is coated with a substance to perform at least one of enhance and inhibit a chemical reaction.

14. An apparatus for separating first particles and second particles from a fluid supporting said first particles and said second particles, said apparatus comprising:

a housing forming a chamber capable of holding said fluid, said housing forming an inlet for allowing said fluid to flow into said chamber, a first outlet for allowing one of said first particles and said second particles to flow out of said chamber, and a second outlet for allowing a remaining one of said first particles and said second particles to flow out of said chamber;

a first electrode array disposed in said chamber and being capable of contacting said fiuld;

a second electrode array disposed in said chamber and being capable of contacting said fluld;

a fluid flow system supplying said fluid to said inlet and removing said fluid from said first and said second outlets, thereby creating a fluid flow within said chamber;

a frequency source operatively coupled to said first and said second electrode arrays and adapted to establish a dielectrophoretic field between said first electrode army and said second electrode array;

control means for controlling said frequency source, said control means providing that said dielectrophoretic field includes a first dielectrophoretic force and a second dielectrophoretic force in an alternating fashion, said first dielectrophoretic force being experienced by at least one of sald first particles and said second particles, and said second dielectrophoretic force being experienced by at least one of said first particles and said second particles.

15. An apparatus according to claim 14, wherein:

said first electrode array and said second electrode array are interdigitated, castellated electrodes.

16. An apparatus according to claim 14, wherein said frequency source is a single frequency generator.

17. A method for selectively separating first type particles from second type particles, said method comprising:

flowing a fluid containing said first type particles and said second type particles into a chamber formed by a housing, said chamber having a first and a second electrode array disposed therein, said housing forming a first inlet, a second inlet, a third inlet, a first outlet, and a second outlet, said fluid flowing into said chamber through said first inlet;

activating a power source to establish a dielectrophoretic field between said first electrode array and said second electrode array to cause a first resultant force to be experienced by said first type particles and flowing a second fluid, containing none of said first type and said second type particles, through said second inlet to cause said second type particles to move in a first directlon, said second fluid exiting said chamber through said first outlet;

deactivating said power source and flowing said second fluid through said third inlet to cause said first type particles and said second type particles to move in said second direction, said second direction being in a direction opposite to said first direction, said second fluid exiting said chamber through said second outlet; and

reapplying said power source to reestablish said dielectrophoretic field between said first electrode array and said second electrode array; and

flowing said second fluid through said second inlet to cause said second type particles to move in said first direction, said second fluid exiting said chamber through said first outlet.

18. A method according to claim 17, wherein:

said fluid flows into said chamber through said first inlet by an action of a first pump,

said fluid flows into said chamber through said second inlet by an action of a second pump, and

said fluid flows into said chamber through said third inlet by an action of a third pump.

19. A method acoording to claim 17 or 18, wherein each of said first and said second electrode arrays comprises sub-groups of electrodes, and said dielectrophoretic field is changed by activating said sub-groups of said first electrode array and said sub-groups of said second electrode array in a cyclic manner.

20. A method according to claim 18, wherein when said fluid flows through said chamber, said flowing is accomplished by urging said fluid through said chamber using a pressure source.

21. A method according to claim 20, wherein:

at least one of said second type particles and said first-type particles are removed from said chamber using said pressure source.

22. A method according to claim 17, further comprising:

labelling at least one of said first type particles and said second type particles of one of on and before entering said chamber in order to enhance separation of said second type particles from said first type particles.

23. A method according to claim 22, wherein;

said step of labeling uses gold to label said at least one of said first type particles and said second type particles.