Particle sorter comprising a fluid displacer in a closed-loop fluid circuit

1. A method of isolating a particle of interest from a plurality of particles in a fluid sample which comprises:

identifying the particle of interest in a fluid stream flowing through a primary microchannel;

inducing a fluid displacer in a closed-loop fluid circuit to give a secondary flow which causes a flow path and direction of the particle of interest that are different from that of the plurality of particles,

wherein the closed-loop fluid circuit is a conduit having a fluid therein, said conduit links, in a closed-loop, a first side of the fluid displacer to a first side of the primary microchannel and a second side of the fluid displacer to a second side of the primary microchannel, such that the fluid displacer, when induced, simultaneously causes the first side of the fluid displacer to push the fluid in the conduit toward the first side of the primary microchannel and the second side of the fluid displacer to pull the fluid in the conduit from the second side of the primary microchannel toward the second side of the fluid displacer.

2. The method of claim 1 , wherein the fluid displacer is bidirectional or unidirectional.

3. The method of claim 1 , wherein the fluid displacer is a piezo-actuated element.

4. The method of claim 1 , and further comprising focusing the plurality of particles to flow in single file through the primary microchannel.

5. The method of claim 1 , and further comprising identifying a second particle of interest in the fluid stream and inducing a second fluid displacer in a second closed-loop fluid circuit to give a second secondary flow.

6. The method of claim 5 , wherein the second fluid displacer may be the same or different from the fluid displacer, the second closed-loop fluid circuit may be the same or different closed-loop fluid displacer, the second secondary flow causes a second flow path and direction of the second particle of interest that may be the same or different from that of the particle of interest, or a combination thereof.

7. The method of claim 1 , which comprises employing a plurality of fluid displacers to cause each particle of a plurality of particles to flow in a plurality of directions.

8. The method of claim 1 , and further comprising encapsulating the particle of interest in a microdroplet.

9. The method of claim 1 , wherein the particle of interest is encapsulated in a microdroplet by itself.

10. The method of claim 1 , wherein actuation of the fluid displacer introduces a volume of fluid from the conduit into the primary microchannel and simultaneously removes a volume of fluid from the fluid stream from the primary microchannel, wherein the volume of the fluid from the conduit and the volume of fluid from the fluid stream are equal.

11. The method of claim 10 , wherein the volume of fluid from the fluid stream that is removed from the primary microchannel is a fluid packet and the particle of interest is fully located within the fluid packet.

12. The method of claim 10 , wherein fluid displacer is in direct fluidic communication with the fluid in the closed-loop fluid circuit.

13. The method of claim 1 , wherein the closed-loop fluid circuit comprises an inline fluid displacer and two fluid conduits that link the sides of the fluid displacer to the respective sides of the primary flow path of the fluid sample.

14. The method of claim 1 , wherein the closed-loop fluid circuit is at a transverse orientation to the primary flow path.

15. The method of claim 1 , wherein the fluid in the closed-loop fluid circuit is compatible and miscible with the fluid in the primary microchannel.

16. A device which comprises:

at least one primary microchannel; and

at least one closed-loop fluid circuit which intersects the primary microchannel and comprises at least one fluid displacer, said closed-loop fluid circuit is configured to be a conduit that links, in a closed-loop, a first side of the fluid displacer to a first side of the primary microchannel and a second side of the fluid displacer to a second side of the primary microchannel, such that inducement of the fluid displacer simultaneously causes the first side of the fluid displacer to push a fluid in the conduit toward the first side of the primary microchannel and the second side of the fluid displacer to pull the fluid in the conduit from the second side of the primary microchannel toward the second side of the fluid displacer.

17. The device of claim 16 , and further comprising at least one nonselective transport mechanism.

18. The device of claim 16 , and further comprising a sample reservoir, a conduit network, an output receptacle, a sensor, a second microchannel which branches from the primary microchannel, or a combination thereof.

19. The device of claim 16 , which comprises a plurality of closed-loop fluid circuits each having at least one fluid displacer which closed-loop fluid circuits are successively arranged along the length of the primary microchannel.

20. The device of claim 16 , wherein the fluid displacer is bidirectional or unidirectional.

21. The device of claim 16 , wherein the fluid displacer is a piezo-actuated element.