METHOD AND APPARATUS FOR POINT OF CARE OSMOLARITY TESTING

• US 20070086927A1
• Filed: 10/14/2005
• Published: 04/19/2007
• Est. Priority Date: 10/14/2005
• Status: Active Grant

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Natarajan, Govindarajan, Partington, Scott, Reddy, Srinivasa, Humenik, James
• Granted Patent: US 7,344,679 B2
• Time in Patent Office: Days
• US Class Current: 422/102
• CPC Class Codes: G01N 13/04 Investigating osmotic effects
• CPC Class Codes: Y10T 436/11 Automated chemical analysis

Abstract

An apparatus and a method are disclosed for providing point of care testing for osmolarity of a bodily fluid. An apparatus is disclosed as having a fluid pathway passing through it for receiving and testing a sample fluid. The invention permits osmolarity testing of a sample fluid wherein the sample fluid has a volume of less than approximately 30 nL, and implements a method and device to measure fluid osmolarity in a clinical setting quickly and accurately, while also reducing evaporation of the fluid.

Claims

1. A sample receiving chip comprising:

a substrate having a fluid pathway passing through the substrate for receiving a sample fluid, the fluid pathway including a first port, at least one second port, and a recessed channel, the recessed channel enclosed in the substrate; and

at least two electrodes positioned in the substrate to contact the sample fluid in the recessed channel to measure properties of the sample fluid.

2. The chip of claim 1, wherein the substrate further comprises one of:

a) at least two electrode windows to provide access to the at least two electrodes; and

b) the at least two electrodes connected to contacts, the contacts positioned on an external surface of the substrate.

3. The chip of claim 1, wherein the substrate is multilayer.

4. The chip of claim 1, wherein the substrate is cordierite-based glass ceramic and the at least two electrodes are cosintered with copper, nickel, and glass ceramic.

5. The chip of claim 1, wherein the sample fluid has a volume of less than approximately 30 nL.

6. The chip of claim 1, wherein the first port funnels the sample fluid into the recessed chamber and the at least one second port vents the recessed channel.

7. The chip of claim 1, wherein the chip is coupled to a device including a base member;

a sample receiving chip fixed to the base member for receiving a sample fluid; and

a conduit fixed to the base member for depositing the sample fluid on the sample receiving chip, the conduit including a first end and a second end.

8. A device for osmolarity testing, comprising:

a base member;

a sample receiving chip fixed to the base member for receiving a sample fluid; and

a conduit fixed to the base member for depositing the sample fluid on the sample receiving chip, the conduit including a first end and a second end.

9. The device of claim 8, further comprising a capillary receptacle including:

a base unit, including a fastener for fixing the conduit to the base unit, and a chamber for receiving the first end of the conduit, the chamber including a substantially flexible partition; and

a mechanism for applying external pressure to the substantially flexible partition for altering chamber pressure to discharge the sample fluid from the second end of the conduit.

10. The device of claim 8, wherein the sample receiving chip comprises:

a substrate having a fluid pathway passing through the substrate for receiving a sample fluid, the fluid pathway including a first port, at least one second port, and a recessed channel, the recessed channel enclosed in the substrate; and

at least two electrodes positioned in the substrate to contact the sample fluid in the recessed channel to measure properties of the sample fluid.

11. The device of claim 10, wherein the substrate further comprises one of:

a) at least two electrode windows to provide access to the at least two electrodes; and

b) the at least two electrodes connected to contacts, the contacts positioned on an external surface of the substrate.

12. The device of claim 10, wherein the substrate is cordierite-based glass ceramic and the at least two electrodes are cosintered with copper, nickel, and glass ceramic.

13. The chip of claim 10, wherein the first port funnels the sample fluid into the recessed chamber and the at least one second port vents the recessed channel.

14. The device of claim 10, wherein the first end of the conduit extracts the sample fluid and the second end of the conduit deposits the sample fluid on the sample receiving chip.

15. The device of claim 8, wherein the base member further includes an electrical conductivity measurement circuit configured to determine osmolarity of the sample fluid.

16. A method for determining osmolarity of a sample fluid, comprising the steps of:

communicating a sample fluid through a conduit fixed to a base member directly to a sample receiving chip; and

determining osmolarity of the sample fluid.

17. The method of claim 16, wherein the sample receiving chip includes:

a substrate having a fluid pathway passing through the substrate for receiving a sample fluid, the fluid pathway including a first port, at least one second port, and a recessed channel, the recessed channel enclosed in the substrate; and

at least two electrodes cosintered with multilayer ceramic positioned in the substrate to contact the sample fluid in the recessed channel to measure properties of the sample fluid.

18. The method of claim 16, wherein the step of communicating includes applying an external pressure to a base unit, the base unit including a chamber for receiving a first end of the conduit, wherein the chamber includes a substantially flexible partition.

19. The method of claim 16, wherein the step of determining the osmolarity of the sample fluid includes measuring the conductivity of the sample fluid to obtain a conductivity value and converting the conductivity value to a corresponding osmolarity value.

20. The method of claim 16, wherein the communicating step includes contacting an in vivo sample of bodily fluid on the human eye, whereby the sample fluid is drawn into the conduit by capillary force.