Method and apparatus for the separation and quantification of particles

1. A method for the separation of a sample of particles comprising at least first and second particles, comprising:

i. generating a force field characterized by at least one point of stable equilibrium for said at least first and second particles; and

ii. moving said at least one point of stable equilibrium in space and for at least one time interval with a speed substantially comparable to a speed of movement of the first particles, and substantially different from a speed of movement of the second particles.

2. The method as in claim 1 , wherein said force field comprises at least one of the following forces:

i. positive dielectrophoresis,

ii. negative dielectrophoresis,

iii. electrophoresis, and

iv. electrohydrodynamic flows.

3. The method as in claim 1 , wherein said speeds of movement of the first and second particles are affected by at least one of the following forces:

i. viscous friction (NI), and

ii. gravity (G).

4. The method as in claim 2 , wherein said force field is generated by at least one substantially planar array of electrodes, disposed on a first substrate.

5. The method as in claim 1 , wherein said force field has a plurality of points of stable equilibrium with a spatial periodicity in at least one region of space.

6. The method as in claim 5 , comprising moving said at least one point of stable equilibrium with a periodic speed.

7. The method as in claim 6 , wherein moving the at least one point of stable equilibrium with a periodic speed comprises:

i. moving said force field with a speed of movement comparable to the speed of movement of said first particles in a direction for a first period of time move said force field a distance equal to one spatial period; and

ii. stopping the field for a second period of time;

so as to obtain a net movement of only said first particles in said direction.

8. The method as in claim 6 , wherein moving the at least one point of stable equilibrium with a periodic speed comprises:

i. moving said force field with a speed of movement comparable to the speed of movement of said first particles in a first direction for a first period of time to move said force field a distance equal to one spatial period;

ii. stopping said force field for a second period of time; and

iii. moving said force field at a second speed comparable to the speed of movement of said second particles in a second direction opposite to said first direction, for a third period of time to move said force field a distance equal to one spatial period;

so as to obtain a net movement of only said second particles in the second direction.

9. The method as in claim 6 , wherein moving the at least one point of stable equilibrium with a periodic speed comprises:

i. moving said force field with a speed of movement comparable to the speed of movement of said first particles in a first direction for a first period of time to move said force field a distance equal to one spatial period minus a spatial period of electrodes;

ii. stopping said force field for a second period of time; and

iii. repeating the preceding steps i) and ii) for a number of times equal to one spatial period of said force field divided by the spatial period of the electrodes;

so as to obtain a net movement of said first particles in said first direction and a net movement of said second particles in a second direction opposite to said first direction.