SYSTEMS AND METHODS FOR ACTIVE PARTICLE SEPARATION
A device and method for extracting particles contained in a ferrofluid medium are provided. Such methods may comprise suspending particles of different sizes in a ferrofluid medium and containing the ferrofluid medium in a cylindrical reservoir, and applying a first magnetic field to at least a portion of the reservoir. The first magnetic field is configured to indirectly exert a force on at least a portion of the particles of a predetermined size, and direct the portion of particles in a desired direction.
1 . A method for extracting particles contained in a ferrofluid medium, the method comprising:
suspending particles of different sizes in a ferrofluid medium and containing the ferrofluid medium in a cylindrical reservoir;
applying a first magnetic field to at least a portion of the reservoir,
wherein the first magnetic field is configured to:
indirectly exert a force on at least a portion of the particles of a predetermined size, and
direct the portion of particles in a desired direction.
2 . The method of claim 1 , wherein applying the first magnetic field includes surrounding at least the portion of the reservoir with the magnetic field.
3 . The method of claim 1 , wherein the particles comprise at least one of biological cells and moieties.
4 . The method of claim 1 , where the reservoir includes or is in communication with an extraction opening.
5 . The method of claim 4 , wherein the desired direction is toward the extraction opening.
6 . The method of claim 4 , wherein the desired direction is away from the extraction opening.
7 . The method of claim 1 , wherein the desired direction is toward a central axis of the reservoir.
8 . The method of claim 1 , wherein the desired direction is away from a central axis of the reservoir.
9 . The method of claim 1 , wherein the predetermined size comprises smaller particles relative to the remainder of the particles in the ferrofluid medium.
10 . The method of claim 1 , wherein the predetermined size comprises larger particles relative to the remainder of the particles in the ferrofluid medium.
11 . The method of claim 1 , wherein a flow outlet is provided on and/or in communication with the reservoir.
12 . The method of claim 11 , wherein the exerted force is configured such that the portion of particles is carried away in a flow out of the reservoir via the flow outlet.
13 . The method of claim 12 , further comprising applying an external force on the reservoir to establish the flow out the flow outlet.
14 . The method of claim 13 , wherein the external force is applied via a pressure source.
15 . The method of claim 14 , wherein the pressure source is a pump.
16 . The method of claim 5 , further comprising accelerating a flow of the portion of particles via a second magnetic field, the second magnetic field generated by a second magnetic field source arranged on a portion of the reservoir positioned opposite to the extraction opening.
17 . The method of claim 1 , further comprising providing a membrane within the reservoir.
18 . The method of claim 17 , wherein the membrane comprises a non-magnetic membrane configured with pore sizes larger than particles within the reservoir to direct particles in a second desired direction.
19 . The method of claim 18 , wherein the second desired direction is toward spaces between pores of the membrane, wherein the spaces are configured to retain particles of at least a first size.
20 . The method of claim 18 , wherein the second desired direction is toward pores of the membrane, such that the particles pass through the membrane.
21 . The method of claim 18 , wherein the non-magnetic membrane comprises a plastic sheet.
22 . The method of claim 18 , wherein the membrane is configured to reduce the amplitude of or substantially eliminate the first magnetic field or the effects thereof.
23 . The method of claim 22 , wherein the amplitude is selected based on the size of the portion of the particles.
24 . The method of claim 18 , further comprising a plurality of non-magnetic beads suspended in the ferrofluid, the non-magnetic beads being functionalized with at least one predetermined receptor configured to bind with a target particle contained in the particles within the ferrofluid medium.
25 . The method of claim 24 , wherein the at least one predetermined receptor include at least one of a molecule, a cell, an antibody, DNA or fragment thereof, and a ligand.
26 . The method of claim 24 , wherein the first magnetic field is configured to direct target particles toward space between pores of the membrane which are configured to retain the target particles.
27 . method of claim 26 , further comprising detecting means to at least one of track or count the retained target particles.
28 . The method of claim 17 , further comprising providing at least one other nonmagnetic membrane, wherein the at least one other non-magnetic membrane is parallel to other membranes.
29 . The method of claim 28 , wherein each membrane has a smaller pore size than a previous membrane.
30 . The method of claim 17 , wherein the membrane comprises a magnetic membrane.
31 . The method of claim 30 , wherein the magnetic membrane comprises a thin foil of nickel.
32 . The method of claim 30 , further comprising providing a plurality of magnetic beads suspended in the ferrofluid medium, the magnetic beads being functionalized with at least one predetermined receptor configured to bind with a target particle contained in the particles within the ferrofluid medium.
33 . The method of claim 32 , wherein the magnetic beads are directed toward a surface of the magnetic membrane between the pores.
34 - 60 . (canceled)