Method and apparatus for depositing a biological fluid onto a substrate

1. A method for depositing at least one biological fluid onto a surface of a substrate, said method comprising the steps of:

a) loading at least one thermal bubble-jet printhead with at least one biological fluid;

b) positioning said at least one printhead next to said substrate; and

c) depositing said at least one biological fluid onto said surface by supplying energy E to said at least one printhead, wherein

E> 1.6 *E th

and E th is the threshold energy of the printhead for said biological fluid.

2. The method according to claim 1 , wherein the depositing step includes supplying said at least one printhead with an energy E, such that 1.6*E th <E≦3.0*E th .

3. The method according to claim 1 , wherein the depositing step includes supplying said at least one printhead with an energy E such that 1.8*E th <E≦2.2*E th .

4. The method according to claim 1 , wherein the depositing includes ejecting from said at least one printhead total number of drops ranging from about 0.5×10 6 to about 2×10 6 .

5. The method according to claim 1 , further comprising repeating the step of depositing of said at least one biological fluid onto said surface at least two times.

6. The method according to claim 5 , wherein said depositing step is repeated a number of times ranging from 2 to 100.

7. The method according to claim 5 , wherein said depositing step is repeated a number of times ranging from 2 and 30.

8. The method according to claim 5 , wherein the time period between two subsequent deposits ranges from about 5 to about 600 seconds.

9. The method according to claim 5 , wherein the time period between two subsequent deposits ranges from about from 5 to about 60 seconds.

10. The method according to claim 1 , further comprising filtering said at least one biological fluid before said loading step (a).

11. The method according to claim 1 , wherein the loading step includes loading said at least one thermal bubble-jet printhead with a biological fluid that comprises at least one biological substance dissolved in an aqueous solvent comprising more than 50% by weight of water relative to the total weight of said biological fluid.

12. The method according to claim 1 , wherein said biological fluid comprises at least one of organic fluids, protein solution, tissue and cell lysates, nucleic acid solutions, or nucleic acid analogue solutions.

13. An apparatus for depositing at least one biological fluid onto a surface of a substrate, said apparatus comprising:

a processing device;

a thermal bubble-jet printhead assembly including at least one printhead, wherein the at least one printhead is at least partially loaded with said at least one biological fluid;

a controller connected to said processing device;

a power supply responsive to the controller for supplying energy to said thermal bubble-jet printhead assembly so that said at least one biological fluid is deposited onto said surface, wherein said power supply supplies said at least one printhead with an energy Ei such that

E i >1.6 *E thi

where E thi is the threshold energy of said at least one printhead for said at least one biological fluid.

14. The apparatus according to claim 13 , wherein said at least one printhead is supplied with an energy E i , such that

1.6 *E thi <E i ≦3.0 *E thi.

15. The apparatus according to claim 13 , wherein said at least one printhead (T 1 , T 2 , T 3 ) is supplied with an energy E i , such that

1.8 *E thi <E i ≦2.2 *E thi .

16. A microarray comprising a substrate with a substrate surface and a plurality of biological fluid spots, wherein said microarray is obtained by carrying out a depositing method according to claim 1 .

17. A method of creating a microarray of a plurality of biological fluid spots on a surface of a substrate, comprising utilizing the apparatus according to claim 13 .