Microfluidic particle analysis device

1. A microfluidic particle flow analysis device comprising:

an inlet in fluid communication via a main channel defining a main flow direction with an inlet manifold providing parallel fluid communication with

a bypass channel of hydrodynamic resistance R bypass , and

a measuring channel of hydrodynamic resistance R measuring , the measuring channel having a cross-sectional dimension in the range of 1 μm to 50 μm and further having a sensor system for detecting a particle,

wherein a flow distribution parameter X measuring =R measuring −1 (R measuring −1 +R bypass −1 ) −1 is in the range of 10 −6 to 0.25, wherein the angle of the measuring channel relative to the main flow direction is in the range of 0° to 60°, and wherein the angle of the bypass channel relative to the main flow direction is in the range of 0° to 60°, and

the microfluidic particle flow analysis device further comprises an outlet in fluid communication with the bypass channel and the measuring channel.

2. The microfluidic particle flow analysis device according to claim 1 , wherein the sensor system for detecting a particle comprises a first electrode and a second electrode defining an operating space between the first electrode and the second electrode, which first and second electrodes are in electrical connection via an electric circuit comprising an alternating current (AC) or a direct current (DC) source and a device for monitoring an electrical signal from the first electrode and/or the second electrode.

3. The microfluidic particle flow analysis device according to claim 2 , wherein the sensor system for detecting a particle on the same wall of the measuring channel comprises an excitation electrode located between two reference electrodes, or wherein the sensor system for detecting a particle comprises two sets of an excitation electrode and a reference electrode, where the excitation electrode and the reference electrode are positioned on opposite walls in the measuring channel.

4. The microfluidic particle flow analysis device according to claim 2 , which does not employ hydrodynamic focusing or which does not employ dielectrophoretic focusing.

5. The microfluidic particle flow analysis device according to claim 1 , wherein the bypass channel has a first cross-sectional dimension in the range of 50 μm to 300 μm and a second cross-sectional dimension in the range of 50 μm to 300 μm.

6. The microfluidic particle flow analysis device according to claim 1 , wherein the measuring channel has a first cross-sectional dimension in the range of 5 μm to 20 μm and a second cross-sectional dimension in the range of 5 μm to 20 μm.

7. The microfluidic particle flow analysis device according to claim 1 , wherein the bypass channel has a first cross-sectional dimension in the range of 50 μm to 300 μm and a second cross-sectional dimension in the range of 50 μm to 300 μm, the measuring channel has a first cross-sectional dimension in the range of 5 μm to 20 μm and a second cross-sectional dimension in the range of 5 μm to 20 μm and wherein the ratio of the length of the bypass channel to the length of the measuring channel is in the range of 10 to 200.

8. The microfluidic particle flow analysis device according to claim 7 , wherein the ratio of the hydrodynamic resistance per length of channel of the measuring channel to the hydrodynamic resistance per length of the bypass channel is at least 500.

9. The microfluidic particle flow analysis device according to claim 1 , wherein the measuring channel and the bypass channel have a cross-sectional dimension in the range of 5 μm to 100 μm.

10. The microfluidic particle flow analysis device according to claim 9 , wherein the bypass channel has a second cross-sectional dimension in the range of 200 μm to 1000 μm.

11. The microfluidic particle flow analysis device according to claim 10 , wherein the ratio of the hydrodynamic resistance per length of the measuring channel to the hydrodynamic resistance per length of the bypass channel is in the range of 50 to 500.

12. The microfluidic particle flow analysis device according to claim 1 , wherein the angle between the measuring channel and the bypass channel is in the range of 0° to 60°.

13. The microfluidic particle flow analysis device according to claim 1 , wherein the measuring channel defines an entry plane in the cross-section of the main channel, which entry plane is orthogonal to the main flow direction.

14. The microfluidic particle flow analysis device according to claim 1 , wherein the microfluidic particle flow analysis device comprises a flow distribution device for receiving a flow of liquid from the inlet, which inlet is at an angle to a plane housing the flow distribution device, and which flow distribution device comprises from 2 to 8 collection channels positioned around an inlet point with each collection channel being in fluid communication with the main channel.

15. The microfluidic particle flow analysis device according to claim 1 , wherein the length of the measuring channel is in the range of 10 μm to 5000 μm.

16. The microfluidic particle flow analysis device according to claim 1 , wherein the features in the microfluidic particle flow analysis device have tolerances about ±1 μm.

17. A method of detecting a particle in a fluid, the method comprising:

providing a microfluidic particle flow analysis device comprising an inlet in fluid communication via a main channel defining a main flow direction with an inlet manifold providing parallel fluid communication with

a bypass channel of hydrodynamic resistance R bypass , and

a measuring channel of hydrodynamic resistance R measuring , the measuring channel having a cross-sectional dimension in the range of 1 μm to 50 μm and further having a sensor system for detecting a particle,

wherein a flow distribution parameter X measuring =R measuring −1 (R measuring −1 +R bypass −1 ) −1 is in the range of 10 −6 to 0.25, wherein the angle of the measuring channel relative to the main flow direction is in the range of 0° to 60°, and wherein the angle of the bypass channel relative to the main flow direction is in the range of 0° to 60°, and

the microfluidic particle flow analysis device further comprises an outlet in fluid communication with the bypass channel and the measuring channel;

providing a sample fluid;

applying a flow of the sample fluid from the inlet to the outlet of the microfluidic particle flow analysis device; and

detecting a particle having a dimension in the range of 0.1 μm to 10 μm, when present in the sample fluid, in the measuring channel using the sensor system for detecting a particle.

18. A method of monitoring a concentration of particles in a fluid, the method comprising:

providing a microfluidic particle flow analysis device comprising an inlet in fluid communication via a main channel defining a main flow direction with an inlet manifold providing parallel fluid communication with

a bypass channel of hydrodynamic resistance R bypass , and

a measuring channel of hydrodynamic resistance R measuring , the measuring channel having a cross-sectional dimension in the range of 1 μm to 50 μm and further having a sensor system for detecting a particle,

wherein a flow distribution parameter X measuring =R measuring −1 (R measuring −1 +R bypass −1 ) −1 is in the range of 10 −6 to 0.25, wherein the angle of the measuring channel relative to the main flow direction is in the range of 0° to 60°, and wherein the angle of the bypass channel relative to the main flow direction is in the range of 0° to 60°, and

the microfluidic particle flow analysis device further comprises an outlet in fluid communication with the bypass channel and the measuring channel;

providing a sample fluid containing particles having a dimension in the range of 0.1 μm to 10 μm;

applying a flow of the sample fluid from the inlet to the outlet of the microfluidic particle flow analysis device; and

monitoring the concentration of the particles in the measuring channel using the sensor system for detecting a particle.

19. A method of detecting a particle in a fluid, the method comprising:

providing a microfluidic particle flow analysis device comprising an inlet in fluid communication via a main channel defining a main flow direction with an inlet manifold providing parallel fluid communication with

a bypass channel of hydrodynamic resistance R bypass , and

a measuring channel of hydrodynamic resistance R measuring , the measuring channel having a cross-sectional dimension in the range of 1 μm to 50 μm and further having a sensor system for detecting a particle, which sensor system for detecting a particle comprises a first electrode and a second electrode defining an operating space between the first electrode and the second electrode, which first and second electrodes are in electrical connection via an electric circuit comprising an alternating current (AC) or a direct current (DC) source and a device for monitoring an electrical signal from the first electrode and/or the second electrode,

wherein a flow distribution parameter X measuring =R measuring −1 (R measuring −1 +R bypass −1 ) −1 is in the range of 10 −6 to 0.25, wherein the angle of the measuring channel relative to the main flow direction is in the range of 0° to 60°, and wherein the angle of the bypass channel relative to the main flow direction is in the range of 0° to 60°, and

the microfluidic particle flow analysis device further comprises an outlet in fluid communication with the bypass channel and the measuring channel;

providing a sample fluid;

applying a flow of the sample fluid from the inlet to the outlet of the microfluidic particle flow analysis device;

applying an AC or DC current from the current source to create an electric field in the operating space, and monitoring a differential electrical signal between the first electrode and the second electrode; and

detecting a particle having a dimension in the range of 0.1 μm to 10 μm, when present in the sample fluid, in the measuring channel using the differential electrical signal.

20. The method of detecting a particle in a fluid according to claim 17 , wherein the concentration of particles in the sample fluid is in the range of 0 ml −1 to 10 8 ml −1 .

21. The method of detecting a particle in a fluid according claim 17 , wherein a volumetric flow in the range of 10 μl/min to 10 ml/min is applied to the inlet of the microfluidic particle flow analysis device.

22. A method of monitoring the concentration of particles in a fluid, the method comprising:

providing a microfluidic particle flow analysis device comprising an inlet in fluid communication via a main channel defining a main flow direction with an inlet manifold providing parallel fluid communication with

a bypass channel of hydrodynamic resistance R bypass , and

a measuring channel of hydrodynamic resistance R measuring , the measuring channel having a cross-sectional dimension in the range of 1 μm to 50 μm and further having a sensor system for detecting a particle, which sensor system for detecting a particle comprises a first electrode and a second electrode defining an operating space between the first electrode and the second electrode, which first and second electrodes are in electrical connection via an electric circuit comprising an alternating current (AC) or a direct current (DC) source and a device for monitoring an electrical signal from the first electrode and/or the second electrode,

wherein a flow distribution parameter X measuring =R measuring −1 (R measuring −1 +R bypass −1 ) −1 is in the range of 10 −6 to 0.25, wherein the angle of the measuring channel relative to the main flow direction is in the range of 0° to 60°, and wherein the angle of the bypass channel relative to the main flow direction is in the range of 0° to 60°, and

the microfluidic particle flow analysis device further comprises an outlet in fluid communication with the bypass channel and the measuring channel;

providing a sample fluid containing particles having a dimension in the range of 0.1 μm to 10 μm;

applying a flow of the sample fluid from the inlet to the outlet of the microfluidic particle flow analysis device;

applying an AC or DC current from the current source to create an electric field in the operating space; and

monitoring a concentration of the particles in the measuring channel by monitoring a differential electrical signal between the first electrode and the second electrode.