Microdialysis system

• US 20020082490A1
• Filed: 07/20/2001
• Published: 06/27/2002
• Est. Priority Date: 08/04/2000
• Status: Active Grant

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Inventors: Hoerauf, Christian, Schoemaker, Michael, Roeper, Josef
• Granted Patent: US 6,591,126 B2
• Time in Patent Office: Days
• US Class Current: 600/347
• CPC Class Codes: A61B 5/14528 invasively
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement

Abstract

The invention concerns a microdialysis system comprising a microdialysis probe (12) that can be inserted into organic tissue (10) and has a dialysis membrane (28) to separate a probe channel (18) filled with perfusion fluid from the tissue (10), a sensor cell (14) to determine the concentration of components and especially glucose in the perfusion fluid that is conveyed from the microdialysis probe (12) and a transport device (16) to convey the perfusion fluid through the probe channel (18) of the microdialysis probe (12) to the sensor cell (14). In order to enable a substantially pressureless transport of perfusion fluid through the microdialysis probe and thus to prevent undesired passage of fluid through the dialysis membrane (28), it is proposed that the transport device (16) has a pressure pump unit (30) connected on the pressure side to the inlet (20) of the probe channel (18) and a suction pump unit (31) connected on the suction side to the outlet (24) of the probe channel (18) that can be operated simultaneously with the pressure pump unit (30).

Claims

1. Microdialysis system comprising a microdialysis probe (12) that can be inserted in organic tissue (10) and has a dialysis membrane (28) to separate a probe channel (18) filled with perfusion fluid from the tissue (10), a sensor cell (14) for the preferably electrochemical detection of components and especially glucose in the perfusion fluid that is conveyed from the microdialysis probe (12) and a transport device (16) to convey the perfusion fluid through the probe channel (18) of the microdialysis probe (12) to the sensor cell (14), characterized in that the transport device (16) has a pressure pump unit (30) connected on the pressure side to the inlet (20) of the probe channel (18) and a suction pump unit (31) connected on the suction side to the outlet (24) of the probe channel (18) operating simultaneously with the pressure pump unit (30).

2. Microdialysis system as claimed in claim 1, characterized in that the pressure side of the pressure pump unit (30) is exclusively connected to the inlet (20) and the suction side of the suction pump unit (31) is exclusively connected to the outlet (24) of the probe channel (18).

3. Microdialysis system as claimed in claim 1 or 2, characterized in that the pressure pump unit (30) and the suction pump unit (31) are each connected via a non-branching duct (36, 38), preferably comprising a flexible tube, to the probe channel (18) of the microdialysis probe.

4. Microdialysis system as claimed in one of the claims 1 to 3, characterized in that the delivery rates of the pressure and suction pump unit (30, 31) are matched in order to reduce the effective pressure difference across the dialysis membrane (28) between the perfusion and tissue fluid.

5. Microdialysis system as claimed in one of the claims 1 to 4, characterized in that the delivery rates of the pressure and suction pump unit (30, 31) are essentially equal.

6. Microdialysis system as claimed in one of the claims 1 to 4, characterized in that the delivery rate of the pressure pump unit (30) is larger by a predetermined amount than the delivery rate of the suction pump unit (31).

7. Microdialysis system as claimed in one of the claims 1 to 6, characterized in that the delivery rate of the pressure and suction pump unit (30, 31) is less than 1 μ

l, preferably less than 0.1 μ

l per minute.

8. Microdialysis system as claimed in one of the claims 1 to 7, characterized in that the suction side of the pressure pump unit (30) is connected to a reservoir (34) for perfusion fluid.

9. Microdialysis system as claimed in one of the claims 1 to 8, characterized in that the pressure side the suction pump unit (31) is connected to a flow chamber (52) of the sensor cell (14) which preferably terminates in a collecting vessel (54).

10. Microdialysis system as claimed in one of the claims 1 to 9, characterized by a reagent pump unit (44) for metering a reagent solution and in particular an enzyme solution into the perfusion fluid upstream of the sensor cell (14).

11. Microdialysis system as claimed in claim 10, characterized in that the pressure side of the reagent pump unit (44) and of the suction pump unit (31) are connected to a connecting duct (42) leading to the sensor cell (14) preferably via a Y connecting piece (40).

12. Microdialysis system as claimed in one of the claims 1 to 11, characterized in that the pressure pump unit (30), the suction pump unit (31) and optionally the reagent pump unit (44) each comprise a flexible pump tube of a multichannel peristaltic pump actuated by a common rotary piston (50).

13. Microdialysis system as claimed in one of the claims 1 to 12, characterized in that the microdialysis probe (12) comprises a double-lumen catheter (22, 26) which has in the area of its distal end a micropore dialysis membrane (28) formed from hollow fibres the outside of which is embedded in the tissue (10) and the inside of which is supplied with perfusion fluid.