Microfluid device and method of producing diffusively built gradients

1. A microfluid device for producing diffusively built gradients, comprising a bottom plate and a cover plate, wherein

the cover plate includes a plurality of recesses and is connected with the bottom plate in a liquid-tight manner so that the recesses form at least two reservoirs immediately adjacent to an observation chamber, wherein the observation chamber provides fluid communication between the reservoirs at a respective at least two first junctures with the reservoirs on respective at least two first sides of the observation chamber,

the cover plate includes a first inlet through which at least one said reservoir can be filled,

the cross-sectional area of the observation chamber at each of the first juncture with the reservoirs is at least 5 times smaller than the maximum cross-sectional area of the reservoir,

the microfluid device additionally comprises at least one channel with at least a second inlet at the cover plate, wherein the at least one channel is in fluid communication with the observation chamber at a respective at least one second juncture with the observation chamber at a respective at least one second side of the observation chamber different than the first sides, and

the observation chamber includes at least one cell adhesion surface.

2. A microfluid device as claimed in claim 1 , wherein the reservoir that can be filled comprises an inlet, wherein the minimal cross-sectional area of the inlet is between 0.03 mm 2 and 13 mm 2 , particularly between 0.2 mm 2 and 3.2 mm 2 .

3. A microfluid device as claimed in claim 1 , wherein the cross-sectional area of the observation chamber is between 0.05 mm 2 and 0.4 mm 2 , preferably between 0.075 mm 2 and 0.1 mm 2 , and/or the cross-sectional area of a reservoir is between 0.25 mm 2 and 8 mm 2 , preferably between 0.37 mm 2 and 2 mm 2 .

4. A microfluid device as claimed in claim 1 , wherein a through hole through the cover plate and/or the bottom plate into the observation chamber is provided.

5. A microfluid device as claimed in claim 1 , wherein the bottom of the observation chamber and the bottom of at least one reservoir are located on one plane.

6. A microfluid device as claimed in claim 1 , wherein the bottom plate consists of an optically high-quality material at least in the area of the observation chamber.

7. A microfluid device as claimed in claim 1 , wherein the bottom of the channel is located on the same plane as the bottom of the observation chamber.

8. A microfluid device as claimed in claim 1 , wherein at least one of the height and the width of at least one of the observation chamber and the reservoirs is constant.

9. A microfluid device as claimed in claim 1 , which comprises at least two further reservoirs, wherein the reservoirs are arranged on the sides of the observation chamber in a manner that two reservoirs each oppose one another.

10. A microfluid device as claimed in claim 1 , wherein the cell adhesion surface has a rectangular, rhombical, triangular or round shape.

11. A microfluid device as claimed in claim 1 , which comprises at least one marking in the observation chamber to determine the location and/or velocity of migrating cells.

12. A microfluid device, particularly as claimed in claim 1 , comprising a bottom plate and a cover plate, wherein the cover plate comprises a recess and is connected to the bottom plate in a liquid-tight manner so that the recess forms an observation chamber, wherein the observation chamber is partially filled with gel.

13. A microfluid device as claimed in claim 12 , wherein the gel is a matrigel, collagen gel or agarose.

14. An arrangement for producing diffusively built gradients with at least two microfluid devices as claimed in claim 1 , wherein the at least two bottom plates are formed as one single bottom plate and the at least two cover plates are formed as one single cover plate.

15. A method of producing diffusively built gradient, comprising the following steps:

providing a microfluid device with two reservoirs and one observation chamber, which connects the reservoirs, particularly a microfluid device according to claim 1 ,

filling the reservoirs and the observation chamber with a neutral liquid;

adding a chemical solution of a known concentration into a reservoir of the microfluid device;

liquid-tight locking of the reservoir so that in the case of a pressure load of the liquid in the reservoir with 10 times its weight, the absolute compression in the reservoir is a maximum of 10% of the volume of the observation chamber;

wherein the microfluid device is formed such that a diffusive gradient that is stable over at least two days is built up.

16. A method as claimed in claim 15 , which additionally comprises the following step:

filling the observation chamber with cells, wherein particularly the filling with cells takes place after the filling with the neutral liquid and before adding the defined concentrated chemical solution.

17. A method as claimed in claim 15 , wherein the microfluid device is provided with two reservoirs and one observation chamber, wherein the volume of each reservoir is at least 100 times, particularly at least 200 times larger than the volume of the observation chamber and/or the cross-sectional surface of the observation chamber at the aperture of the observation chamber into one of the reservoirs is at least 5 times, particularly at least 20 times smaller than the maximum cross-sectional surface of the reservoir in parallel to this cross-sectional surface of the observation chamber and/or the length of the observation chamber is between 100 μm and 5 mm, particularly between 500 μm and 3 mm.

18. A microfluid device as claimed in claim 1 , wherein the cover plate at least partially covers the reservoirs.

19. A microfluid device as claimed in claim 1 , wherein the observation chamber includes a sidewall around an entire periphery of the observation chamber, and wherein the sidewall allows fluid communication only at interfaces with the reservoirs and with the at least one channel.

20. A microfluid device as claimed in claim 1 , wherein the at least one cell adhesion surface takes the form of a physical coating.

21. A microfluid device as claimed in claim 1 , wherein the at least one cell adhesion surface takes the form of a chemical treatment.

22. A microfluid device as claimed in claim 1 , wherein the observation chamber is not in fluid communication with any said reservoir at the second side.

23. A microfluid device as claimed in claim 8 , wherein at least one of the observation chamber and one of the at least two reservoirs has the shape of an even prism with an even number of sides.

24. A microfluid device as claimed in claim 8 , wherein at least one of the observation chamber and one of the at least two reservoirs has the shape of a cuboid.