Process for sorting cells by microfabricated components using a nuclease

1. A process for sorting target particles and non-target cells from a sample by a cell sorting valve microfabricated on a surface of a silicon substrate, with microfabricated channels leading from the cell sorting valve, wherein the cell sorting valve separates the target particles from non-target material;

a disposable cartridge containing a sample reservoir, a sort reservoir and a waste reservoir;

wherein the sample is provided in a buffer comprising nuclease, and wherein the sort reservoir further comprises a siphon structure that collects a smaller sort fluid volume within the siphon structure of the sort reservoir, wherein the smaller sort fluid volume is less than about 10% of a total fluid volume of the sort reservoir.

2. The process according to claim 1 , characterized in that the nuclease is cation-independent.

3. The process according to claim 1 , characterized in that the nuclease is cation-independent and the buffer contains a chelating agent capable of forming complexes with cations.

4. The process according to claim 1 , characterized in that the nuclease is cation-dependent.

5. The process according to claim 1 , characterized in that the nuclease is a DNAse.

6. The process according to claim 1 , characterized in that the nuclease is non-specific.

7. The process according to claim 1 , characterized in that an interposer provides fluid communication between the microfabricated channels in the silicon substrate and the reservoirs in the disposable cartridge.

8. The process according to claim 7 , characterized in that the interposer provides a sort fluid path between a sort reservoir in the disposable cartridge and the sort channel in the silicon substrate, a waste fluid path between a waste reservoir in the disposable cartridge and the waste channel, and a sample fluid path between the sample channel and a sample reservoir.

9. The process according to claim 7 , characterized in that the channels of the interposer are provided at the bottom with an additional small channel having 5 to 20% of the depth and width of the channel it is located in.

10. The process according to claim 1 , characterized in that the cell sorting valve directs the target particles from a sample channel into a sort channel formed in the silicon substrate and the non-target material from the sample channel to a waste channel also formed in the silicon substrate.

11. The process according to claim 1 , characterized in that the sample reservoir further comprises a funnel-shaped feature formed in the wall of the sample reservoir, which collects a smaller volumes of sample fluid, wherein the smaller volume of sample fluid is less that about 10% of a total fluid volume of the sample reservoir.

12. The process according to claim 1 , characterized in that the waste reservoir further comprises a funnel-shaped feature formed in the wall of the waste reservoir, which collects a smaller volume of waste fluid, wherein the smaller volume of waste fluid is less that about 10% of a total fluid volume of the waste reservoir.

13. The process according to claim 1 , characterized in that the sample channel comprises an interrogation means which distinguishes target particles from non-target materials in the sample stream.

14. The process according to claim 13 , characterized in that the interrogation means comprises a laser in a laser-based, induced fluorescence system, wherein a fluorescent tag is affixed to the target particle, and emits a fluorescent signal when irradiated by the laser.