METHOD AND APPARATUS FOR COUPLING A CHANNELED SAMPLE PROBE TO TISSUE

• US 20080319382A1
• Filed: 04/24/2008
• Published: 12/25/2008
• Est. Priority Date: 03/08/2002
• Status: Active Grant

• Current Assignee: GLT Acquisition Corporation
• Original Assignee: GLT Acquisition Corporation
• Inventors: Ruchti, Timothy L., Monfre, Stephen L., Hazen, Kevin H., Blank, Thomas B., Slawinski, Christopher, Brown, Sedar R.
• Granted Patent: US 8,504,128 B2
• Time in Patent Office: Days
• US Class Current: 604/66
• CPC Class Codes: A61B 2562/146 for optical coupling
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: G01N 21/359 using near infrared light

Abstract

Sampling is controlled in order to enhance analyte concentration estimation derived from noninvasive sampling. More particularly, sampling is controlled using controlled fluid delivery to a region between a tip of a sample probe and a tissue measurement site. The controlled fluid delivery enhances coverage of a skin sample site with the thin layer of fluid. Delivery of contact fluid is controlled in terms of spatial delivery, volume, thickness, distribution, temperature, and/or pressure.

Claims

1. A noninvasive spectroscopic analyzer for analyte property determination from a sample site of a body part, comprising:

a sample probe having a sample probe tip,

an optic penetrating through said sample probe and terminating at said sample probe tip,

at least one lumen lying substantially parallel to and proximate to said optic.

2. The analyzer of claim 1, said lumen further comprising:

a transport channel extending between a fluid reservoir and said sample probe tip.

3. The analyzer of claim 2, wherein said fluid reservoir is integrated into said analyzer.

4. The analyzer of claim 2, wherein said fluid reservoir is removably coupled to said analyzer.

5. The analyzer of claim 1, further comprising:

a plurality of lumens, each of said plurality of lumens terminated at a plurality of sites distributed about a center of said sample probe tip.

6. The analyzer of claim 1, said at least one lumen further comprising a hydrophilic coating layer substantially covering an inner surface thereof.

7. The analyzer of claim 1, wherein said at least one lumen terminates at a moat in said sample probe tip, said moat forming a tunnel circumferentially surrounding said central optic when said sample probe tip contacts the body part.

8. A noninvasive spectroscopic analyzer for analyte property determination from a sample site of a body part, comprising:

a sample probe having a sample probe tip comprising at least one microfluidic fluid delivery channel, said delivery channel forming a pathway for dispersion of a coupling fluid when said sample probe tip proximately contacts the body part.

9. The analyzer of claim 8, said channel comprising:

an inner moat circumferentially surrounding an optic embedded in said sample probe.

10. The analyzer of claim 9, further comprising:

a fluid delivery aperture defined through said sample probe tip and terminating proximate to said inner moat, wherein a coupling fluid is delivered from a reservoir via said aperture to said inner moat.

11. The analyzer of claim 10, further comprising:

an outer moat in said sample probe tip, said outer moat circumferentially surrounding said inner moat.

12. The analyzer of claim 10, further comprising:

means for maintaining temperature of said coupling fluid at about ninety to ninety-two degrees Fahrenheit prior to delivery of said coupling fluid to the body part.

13. The analyzer of claim 8, further comprising:

means for creating a negative pressure in said inner moat during use of said analyzer to assist in collecting a noninvasive spectrum of the sample site.

14. The analyzer of claim 8, wherein said microfluidic channel comprises at least one radially extending channel on said sample probe tip.

15. The analyzer of claim 8, wherein said microfluidic channel comprises a moat coupled to at least one radially extending channel.

16. The analyzer of claim 10, further comprising:

means for delivering coupling fluid from a reservoir, via said fluid delivery aperature, to said delivery channel.

17. The analyzer of claim 16, further comprising:

a processor for controlling said means for delivering.

18. The analyzer of claim 17, wherein said processor operates in accordance with a control signal from a sensor.

19. The analyzer of claim 18, wherein said sensor comprises any of:

an electrical contact sensor sensing proximate contact of said sample probe tip with the sample site, wherein upon proximate contact of said sample probe tip with the body part an electrical circuit is completed and said electrical contact sensor generates a signal indicative of completion of said electrical circuit; and

a pressure sensor sensing proximate contact of said sample probe tip with the sample site, wherein said pressure sensor comprises a film layer with air voids internally contained, wherein said pressure sensor generates a charge and corresponding voltage indicative of different capacitive charges measured as pressure is applied to said film layer.

20. The analyzer of claim 8, further comprising:

a processor for controlling positioning of said sample probe tip relative to the sample site.

21. The analyzer of claim 20, wherein said processor operates in accordance with a control signal from a sensor.

22. The analyzer of claim 21, wherein said sensor comprises any of:

an electrical contact sensor sensing proximate contact of said sample probe tip with the sample site, wherein upon proximate contact of said sample probe tip with the body part an electrical circuit is completed and said electrical contact sensor generates a signal indicative of completion of said electrical circuit;

a pressure sensor sensing proximate contact of said sample probe tip with the sample site, wherein said pressure sensor comprises a film layer with air voids internally contained, wherein said pressure sensor generates a charge and corresponding voltage indicative of different capacitive charges measured as pressure is applied to said film layer; and

an optical sensor sensing proximate contact of said sample probe tip with said sample site using spectral responses from said analyzer at about 1450 and/or at about 1900 nm.

23. The analyzer of claim 8, wherein said sample property comprises a glucose concentration and said coupling fluid exhibits a viscosity of less than about 2.2 centistokes.

24. The analyzer of claim 8, wherein said sample property comprises a glucose concentration and said coupling fluid exhibits a refractive index of less than about 1.31.

25. A method of delivery of a fluid to a sample site of a body part, comprising the step of:

delivering fluid from a reservoir through a sample probe head of a near-infrared noninvasive glucose concentration spectroscopic analyzer to the sample site when a sample probe tip of said sample probe head proximately contacts the sample site.

26. The method of claim 25, wherein said step of delivering is performed when said sample tip is within less than about 0.25 mm of the sample site.

27. The method of claim 26, further comprising the step of:

controlling delivery of said fluid at a volume of less than about twenty microliters.

28. The method of claim 27, further comprising the step of:

noninvasively collecting a spectrum, wherein initiation of detection of photons comprising said spectrum commences within less than about ten seconds from said step of delivery of said volume of fluid.

29. The method of claim 28, further comprising the step of:

adjusting temperature of said fluid to within a range of eighty-eight to ninety-four degrees Fahrenheit prior to said step of controlling delivery.

30. The method of claim 27, further comprising the step of:

repeating said step of controlling delivery to deliver a second volume of coupling fluid.

31. The method of claim 30, further comprising the step of:

using an input signal in construction with a computer implemented algorithm pursuant to said step of controlling delivery, wherein said input signal comprises any of;

an electrical contact sensor sensing proximate contact of said sample probe tip with the sample site, wherein upon proximate contact of said sample probe tip with the body part an electrical circuit is completed and said electrical contact sensor generates a signal indicative of completion of said electrical circuit;

a pressure sensor sensing proximate contact of said sample probe tip with the sample site, wherein said pressure sensor comprises a film layer with air voids internally contained, wherein said pressure sensor generates a charge and corresponding voltage indicative of different capacitive charges measured as pressure is applied to said film layer; and

an optical sensor sensing proximate contact of said sample probe tip with said sample site using spectral responses from said analyzer at about 1450 and/or at about 1900 nm.

32. The method of claim 25, further comprising the step of:

delivering the fluid through a transport channel between a fluid reservoir and said sample probe tip, wherein said transport channel comprises at least one lumen.

33. The method of claim 25, further comprising a plurality of lumens, each of said lumens terminating at a plurality of sites distributed about a center of said sample probe tip.

34. The method of claim 33, said at least one lumen comprising a hydrophilic coating layer that covers a portion of an inner surface thereto.

35. The method of claim 32, wherein said at least one lumen terminates at a moat in said sample probe tip, said moat forming a tunnel circumferentially surrounding said central optic when said sample probe tip contacts the body part.

36. The method of claim 25, further comprising the step of:

dispersing fluid through at least one microfluidic fluid delivery channel, said channel forming a pathway for dispersion of a coupling fluid when said sample probe tip proximately contacts the body part.

37. The method of claim 36, wherein said channel comprises an inner moat, said inner moat circumferentially surrounding an optic embedded in said sample probe.

38. The method of claim 37, wherein said step of delivering fluid comprises the step of moving the fluid through a fluid delivery aperature, said fluid delivery aperature extending through said sample probe tip and terminating proximate to said inner moat, wherein said step of delivering moves the coupling fluid from a reservoir through said aperature, and into said inner moat.

39. The method of claim 38, further comprising:

providing an outer moat in said sample probe tip, said outer moat circumferentially surrounding said inner moat.

40. The method of claim 38, further comprising the step of:

maintaining temperature of said coupling fluid at about eighty-eight to ninety-four degrees Fahrenheit prior to delivery of said coupling fluid to the body part.

41. The method of claim 36, wherein said microfluidic channel comprises at least one radially extending channel on said sample probe tip.

42. The method of claim 35, wherein said microfluidic channel comprises a moat coupled to at least one radially extending channel on said sample probe tip.