Microfluidic device and method with trapping of sample in cavities having lids that can be opened or closed

1. A sample preparing arrangement suitable for enhancing detection of different samples comprising a plurality of samples, said arrangement comprising:

a carrier structure including a device for controllable generation of a magnetic field through a control signal that controls the device to generate the magnetic field to attract said plurality of samples towards specific locations on said carrier when connected to a first control signal, wherein said samples comprise magnetic particles;

a controllable releasing force through a second control signal, wherein the controllable releasing force is a force for releasing a known number of the attracted samples; and

a plurality of detection elements, wherein each of said detection elements is integrated in said carrier structure proximal to each of said specific locations, said detection elements enabling detection of localization of said plurality of samples relative to said specific locations.

2. The arrangement as recited in claim 1 , wherein said device is a magnetically active material.

3. The arrangement as recited in claim 1 , wherein said device is made of an electrically conducting material.

4. The arrangement as recited in claim 1 , wherein said device comprises aluminum.

5. The arrangement as recited in claim 1 , wherein said device comprises a plurality of coils for controllable generation of a magnetic field, and wherein a current of different strength is applied through a conductor to each of said plurality of coils.

6. The arrangement as recited in claim 1 , wherein said device comprises a plurality of coils, and a known number of samples localized at each of the specific locations.

7. The arrangement as recited in claim 6 , wherein a current amplitude and the number of windings in the coils are proportional to the strength of the magnetic field.

8. The arrangement as recited in claim 1 , further comprising a cavity provided in the carrier structure.

9. The arrangement as recited in claim 8 , further comprising a magnetic lid for capping said cavity.

10. The arrangement as recited in claim 9 , wherein said magnetic lid comprises a bead, and magnetic material is deposited around said cavity, said bead being directed onto said cavity using external magnets that create magnetic fields counteracting a field created by the material deposited around each cavity.

11. The arrangement as recited in claim 9 , wherein said lid is a micro-bead.

12. The arrangement as recited in claim 6 , wherein said samples are attracted to predetermined specific locations when the plurality of coils proximal to said predetermined specific locations are energized by electric current to produce the magnetic fields of spatial attraction.

13. The arrangement as recited in claim 9 , wherein at least one of said magnetic particles is in the cavity that is capped by the magnetic lid.

14. The arrangement as recited in claim 1 , wherein said samples comprise magnetic particles carrying chemicals.

15. The arrangement as recited in claim 9 , further comprising a control circuit that produces the attractive magnetic field, wherein said capping is detected by detecting a change in inductance in the control circuit, whereby the lid increases the inductance by acting as a magnetic yoke in a transformer.

16. The arrangement as recited in claim 13 , wherein said detection elements detect changes of inductance when said magnetic particle passes into or out of said cavity, wherein a counted number of said particles passes into or out of said cavity, and the detection elements and control of the control signal enable counting of the number of samples passed into or out of said cavity.

17. The arrangement as recited in claim 16 , wherein said detection is determined using the direction of externally controlled magnetic field by changing the direction of electric current flowing through a coil proximal to said cavity or flipping an external magnetic field.

18. The arrangement as recited in claim 16 , wherein said particle includes a molecular coating, which reacts with a fluid in said cavity or with a coating adsorbed on walls of the cavity.

19. The arrangement as recited in claim 1 , wherein said carrier structure comprises a substance selected from a group of substances consisting of: silicon, Si-compound, Si-oxide, Si-nitride, Si-carbide, a polymer, polyethylene, polyethylene glycol, polyethylene oxide, fluorine containing a polymer, silicon containing a polymer and combinations thereof.

20. The arrangement as recited in claim 1 , further comprising a carrier substrate.

21. The arrangement as recited in claim 1 , further comprising a member for generating acoustic waves, wherein said member is positioned on the carrier structure.

22. The arrangement as recited in claim 21 , wherein said device and the member for generating acoustic waves are covered with an insulating layer constituting said carrier substrate.

23. The arrangement as recited in claim 22 , wherein a combination of receptor-bead of a magnetizable material is attached on the insulating layer.

24. The arrangement as recited in claim 23 , wherein a sample is provided with a magnetic portion attractive toward the receptor.

25. The arrangement as recited in claim 24 , wherein said combination of receptor-bead attenuates the acoustic wave stronger than receptors attached to the insulating layer.

26. The arrangement as recited in claim 25 , wherein a surface of the insulating layer is inert to receptors, and the receptor-bead combination is attached to the surface by magnetic forces acting on the bead.

27. The arrangement as recited in claim 1 , further comprising a matrix of interdigitated electrodes, whereby one or more electrode pairs constitute a single site and a capacitor.

28. The arrangement as recited in claim 27 , wherein each site of the matrix on the device comprises a different preparation, said preparations being prepared differently, by using different agents, and by directing beads, with specific molecules attached to them, to said sites using magnetic fields, or withdrawing particles from these sites, the dielectric constant of a layer close to the surface is perturbed and large changes of the capacitance of the device, compared to attachment of only a molecule, is detected.

29. The arrangement of claim 1 , wherein said controllable releasing force comprises a force selected from a group of forces consisting of: gravitational force, shear force of flowing fluid, and magnetic force.

30. The arrangement of claim 1 , wherein said controllable releasing force moves at least one of said attracted samples from a first specific location to a second specific location.

31. The arrangement of claim 1 , wherein the samples comprise magnetic particles, said attraction transforming said particles from a spatially disordered state into a substantially ordered pattern.