Micro-fluidic system
A micro-fluidic system comprising a micro-fluidic channel, which has a wall provided with a hole; and a closing element, which is adapted to cooperate with a partition arranged within the micro-fluidic channel in the area of the hole to isolate or connect two segments of the channel; the closing element is made of a photoresist material, in particular a material obtained by the polymerisation of a photopolymerable material.
1. A micro-fluidic system comprising at least one micro-fluidic channel ( 2 ), which has a first segment ( 4 ), at least one second segment ( 5 ) and at least one wall ( 7 ), which is provided with at least one hole ( 9 ) arranged between the first and the second segment ( 4 , 5 ); and at least one valve ( 3 ), which is arranged along the micro-fluidic channel ( 2 ) in the area of the hole ( 9 ) and comprises an actuator ( 11 ) and a closing element ( 10 ); the actuator ( 11 ) is adapted to displace the closing element ( 10 ) between a locked configuration, in which the closing element ( 10 ) substantially isolates the first and the second segment ( 4 , 5 ) from one another, and an open configuration, in which the first and second segment ( 4 , 5 ) are connected to one another; the closing element ( 10 ) being arranged within the micro-fluidic channel ( 2 ) in contact with said wall ( 7 ) and so as to close the hole ( 9 ) with respect to the micro-fluidic channel ( 2 ); the micro-fluidic system ( 1 ) being characterised in that the closing element ( 10 ) comprises a photoresist material; the micro-fluidic channel ( 2 ) comprising a further wall ( 6 ); the system ( 1 ) comprising at least one spacer element (D), which is arranged in contact with the further wall ( 6 ), at least partially delimits the channel ( 2 ) and comprises a photoresist material.
2. The system according to claim 1 , wherein the closing element ( 10 ) is made of a photoresist material; the spacer element (D) is made of a photoresist material and is arranged between the wall ( 7 ) and the further wall ( 6 ).
3. The system according to claim 1 , wherein the micro-fluidic channel ( 2 ) comprises at least one area, in the area of which the closing element ( 10 ) is absent so as to expose at least part of an inner surface of the wall ( 7 ); the channel ( 2 ) has a section with at least one dimension smaller than 0.5 mm.
4. The system according to claim 1 , wherein the photoresist material is a negative photoresist.
5. The system according to claim 1 , wherein the closing element ( 10 ) has an elastic modulus from 2500 KPa to 4000 KPa.
6. The system according to claim 1 , wherein the photoresist material is selected from the group consisting of: acrylic polymer, polymethylglutarimide, SU-8 and a mixture of diazonaphthoquinone with a phenolformaldehyde.
7. The system according to claim 1 , wherein the photoresist material is cross-linked.
8. The system according to claim 1 , comprising a partition ( 12 ) arranged within the micro-fluidic channel ( 2 ), between the first and the second segment ( 4 , 5 ).
9. The system according to claim 8 , wherein the partition ( 12 ) comprises, in particular consists of, a photoresist material.
10. The system according to claim 9 , wherein the closing element ( 10 ) is curved in the area of the hole ( 9 ) so that, when the actuator ( 11 ) exerts no pressure, the closing element ( 10 ) is separate from the partition ( 12 ).
11. The system according to claim 1 , wherein the micro-fluidic channel ( 2 ) has a section with an equivalent diameter greater than 10 μm.
12. The system according to claim 1 , wherein the closing element ( 10 ) has a thickness from 5 μm to 30 μm.
13. A process for producing a system according to claim 1 , comprising a step of applying a first electromagnetic radiation sensitive material to the wall ( 7 ); a step of irradiating, during which the first electromagnetic radiation sensitive material is partially irradiated with electromagnetic radiation; a step of removing, during which part of the first electromagnetic radiation sensitive material is removed so as to obtain the closing element ( 10 ); a step of overlapping, during which the wall ( 7 ) provided with the closing element ( 10 ) and a further wall ( 6 ) are overlapped to one another and connected to one another; a further step of applying, which precedes the step of overlapping and during which a second electromagnetic radiation sensitive material is applied to the further wall ( 6 ); a step of treating, which follows the further step of applying and precedes the step of overlapping and during which the second electromagnetic radiation sensitive material is partially subjected to electromagnetic radiation and then partially removed so as to obtain the spacer element (D).
14. The process according to claim 13 , wherein the partition ( 12 ) is obtained during the step of treating.
15. The process according to claim 13 , wherein the wall ( 7 ) and the further wall ( 6 ) are overlapped so that the closing element ( 10 ) and the spacer element (D) are arranged therebetween.
16. The process according to claim 13 , wherein the wall ( 7 ) and the further wall ( 6 ) are connected to one another by applying a pressure and providing heat.
17. The process according to claim 13 , wherein the first and the second electromagnetic radiation sensitive material comprise the same material.