Method and apparatus for fractionation using generalized dielectrophoresis and field flow fractionation

• US 6,287,832 B1
• Filed: 09/14/1999
• Issued: 09/11/2001
• Est. Priority Date: 02/23/1996
• Status: Expired due to Term

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Huang, Ying, Wang, Xiao-Bo, Becker, Frederick F., Gascoyne, Peter R. C.
• Primary Examiner(s): Weber, Jon P.
• Application Number:
  US09/395,890
• Time in Patent Office: 728 Days
• Field of Search: 435/173.1, 435/173.9, 424/520
• US Class Current: 435/173.9
• CPC Class Codes: B03C 5/028 using travelling electric fields, i.e. travelling wave dielectrophoresis [TWD]
• CPC Class Codes: G01N 2030/0035 electrical field
• CPC Class Codes: G01N 2030/0065 Dielectric FFF, i.e. opposing forces dominate hydrodynamic lift forces and steric effects
• CPC Class Codes: G01N 30/0005 Field flow fractionation

Abstract

The present disclosure is directed to a novel apparatus and novel methods for the separation, characterization, and manipulation of matter. In particular, the invention combines the use of frequency-dependent dielectric and conductive properties of particulate matter and solubilized matter with the properties of the suspending and transporting medium to discriminate and separate such matter. The apparatus includes a chamber having at least one electrode element and at least one inlet and one output port into which cells are introduced and removed from the chamber. Matter carried through the chamber in a fluid stream is then displaced within the fluid by a dielectrophoretic (DEP) force caused by the energized electrode. Following displacement within the fluid, matter travels through the chamber at velocities according to the velocity profile of the chamber. After the matter has transmitted through the chamber, it exits at the opposite end of the chamber at a characteristic position. Methods according to the invention involve using the apparatus for discriminating and separating matter for research, diagnosis of a condition, and therapeutic purposes. Examples of such methods may include separation of mixtures of cells, such as cancer cells from normal cells, separation of parasitized erythrocytes from normal erythrocytes, separation of nucleic acids, and others.

Claims

1. A method for treating a condition in a patient, wherein said condition is indicated by the presence of an identified matter, said method comprising:

a) obtaining a fluid sample including said identified matter from said patient;

b) obtaining and disposing horizontally a chamber having at least one inlet port and one outlet port, said chamber having an interior surface and an exterior surface, said chamber further having structural characteristics which cause a transport fluid traveling through said chamber to travel at differing velocities according to a velocity profile;

a plurality of electrode elements adapted along a portion of said chamber;

at least one duct entering the chamber to carry said transport fluid through the chamber;

c) introducing said sample of said patient into said at least one inlet port;

d) introducing the transport fluid into the at least one duct, causing a fluid flow at a flow rate according to said velocity profile within said chamber;

e) applying at least one electrical signal provided by an electrical signal generator at a holding frequency of said identified matter to said plurality of electrode elements at different phases, wherein said plurality of electrode elements is energized and creates a traveling electric field, thereby causing at least one dielectrophoretic force on said identified matter having components normal to the direction of said fluid flow;

f) holding said identified matter in close proximity to said plurality of electrode elements;

g) transporting said sample without said identified matter by said transport fluid at a velocity according to said velocity profile;

h) collecting said sample without said identified matter at said at least one outlet port; and

i) returning said sample without said identified matter to said patient to thereby treat said condition.

2. The method of claim 1, wherein said identified matter comprises cancer cells.

3. A method for treating a cancer condition in a patient by separating cancer cells from normal cells utilizing dielectrophoresis and field flow fractionation, said method comprising:

a) obtaining a suspension or fluid sample containing cancer cells and normal cells from said patient;

b) obtaining and disposing horizontally a chamber having at least one inlet and one outlet port, said chamber having an interior surface and an exterior surface, said chamber further having structural characteristics which cause a transport fluid traveling through said chamber to travel at differing velocities according to a velocity profile;

a plurality of electrode elements adapted along a portion of said chamber;

at least one duct entering the chamber to carry said transport fluid through the chamber;

c) introducing said sample into said at least one inlet port;

d) introducing the transport fluid into the at least one duct, causing a fluid flow at a flow rate according to said velocity profile within said chamber;

e) applying at least one electrical signal provided by an electrical signal generator to said plurality of electrode elements at different phases, wherein said plurality of electrode elements is energized and creates a traveling electric field, thereby causing at least one dielectrophoretic force on said cancer cells and said normal cells having components normal to the direction of said fluid flow, thereby displacing said cancer cells from said normal cells;

wherein said cancer cells and said normal cells travel through said chamber at said differing velocities according to said cancer cells and said normal cells respective positions within said transport fluid, and said cancer cells and said normal cells exit from said chamber at said at least one outlet port at positions corresponding to said displacement between said cancer cells and said normal cells; and

returning said normal cells to said patient to thereby treat said cancer condition.

4. A method according to claim 3, wherein said cancer cells and said normal cells exit said at least one outlet port at times proportionate to said differing velocities.

5. A method according to claim 3, wherein said cancer cells and said normal cells exit said at least one outlet port at times proportionate to said cancer cells and said normal cells displacement within said fluid flow.

6. A method for removing preselected matter from a sample containing said preselected matter and non-selected matter, comprising:

a) obtaining a sample containing a suspension or fluid of preselected matter and non-selected matter;

b) obtaining a chamber having inlet and outlet ports, said chamber adapted to cause said sample to flow at differing velocities according to a velocity profile;

an electrode structure adapted along at least a portion of said chamber;

c) introducing said sample into said inlet port;

d) creating a traveling electric field in said chamber to effect a dielectrophoretic force on said sample, said traveling electric field being created at a holding frequency of said preselected matter;

said holding frequency causing said preselected matter to be held in close proximity to said electrode structure; and

e) collecting said sample without said preselected matter at said outlet port.

7. The method of claim 6, wherein said preselected matter comprises cancer cells.

8. The method of claim 6, wherein said sample comprises a blood supply of a patient.

9. The method of claim 6, wherein said sample comprises bone marrow of a patient.