Apparatus for analytical determination of glucose in a biological matrix

• US 5,676,143 A
• Filed: 07/10/1996
• Issued: 10/14/1997
• Est. Priority Date: 11/09/1992
• Status: Expired due to Term

• Current Assignee: Boehringer Mannheim GmbH (Roche Holding AG)
• Original Assignee: Boehringer Mannheim GmbH (Roche Holding AG)
• Inventors: Boecker, Dirk, Simonsen, Jan Henning
• Primary Examiner(s): Bahr, Jennifer
• Assistant Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US08/677,923
• Time in Patent Office: 461 Days
• Field of Search: 128/633, 128/664, 128/665, 356/39, 356/40, 356/41
• US Class Current: 600/316
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 2562/046 in a matrix array
• 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: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6833 Adhesive patches
• CPC Class Codes: A61B 5/6838 Clamps or clips

Abstract

An apparatus for determination of a glucose concentration in a biological matrix includes an irradiation device for irradiating light as primary light into a biological matrix, and a detection device for measuring intensity of light emerging as secondary light through the boundary surface of the biological matrix. The detection device detects light from the irradiation device after the light has propagated along a light path in the biological matrix. A data processing device processes measurement signals from the detection device. The irradiation device provides spatially limited illumination of an irradiation site, and the detection device is configured for spatially limited measurements of the secondary light emerging at the detection site. The detection site is located relative to the irradiation site such that the secondary light is multiply scattered at scattering centers in the biological matrix. The irradiation and detection devices are configured to provide at least two different light paths within the biological matrix during detection measurements, and to perform at least two detection measurements wherein the light paths are different. The detection device generates separate measurement signals for each of the at least two detection measurements. The data processing device converts the separate measurement signals into a signal which corresponds to a glucose concentration in the biological matrix.

Claims

1. An apparatus for determination of a glucose concentration in a biological matrix, said apparatus comprising:

irradiation means for irradiating light as primary light into a biological matrix through a boundary surface thereof;

detection means for measuring an intensity of light emerging as secondary light through the boundary surface of the biological matrix, said detection means being configured to detect light from said irradiation means after the light has propagated along a light path within the biological matrix;

data processing means coupled to said irradiation means and said detection means for processing measurement signals from said detection means;

said irradiation means being configured to provide spatially limited illumination of an irradiation site of said boundary surface, said detection means being configured for spatially limited measurement of the secondary light emerging at a detection site of said boundary surface, wherein the detection site is located relative to the irradiation site such that the secondary light is multiply scattered at scattering centers in the biological matrix;

wherein said irradiation means and said detection means are configured to provide at least two different light paths within the biological matrix during detection measurements between respective irradiation and detection sites, and configured to perform at least two detection measurements wherein the light paths of said at least two detection measurements are different, and are further configured to generate separate measurement signals by said detection means for each of said at least two detection measurements;

wherein said data processing means converts the separate measurement signals measured by said detection means with said different light paths into a signal corresponding to a glucose concentration in the biological matrix.

2. An apparatus according to claim 1, comprising at least two of said irradiation means, each of said at least two irradiation means having essentially corresponding wavelengths, said at least two irradiation means being configured to irradiate light onto different irradiation sites.

3. An apparatus according to claim 1, comprising at least two of said detection means, said at least two detection means being configured to measure secondary light emerging from the biological matrix at two different detection sites.

4. An apparatus according to claim 1, further comprising light blocking means disposed between the irradiation means and the detection means to prevent transmission of primary light from the irradiation means to the detection means by any path other than through the biological matrix.

5. An apparatus according to claim 1, wherein a dimension of the irradiation site in a spatial direction which is defined by the shortest distance to the detection site is no more than 2 mm.

6. An apparatus according to claim 1, wherein a dimension of the irradiation site in a spatial direction which is defined by the shortest distance to the detection site is no more than 1 mm.

7. An apparatus according to claim 1, wherein a dimension of the detection site in a spatial direction which is defined by the shortest distance to the irradiation site is no more than 2 mm.

8. An apparatus according to claim 1, wherein a dimension of the detection site in a spatial direction which is defined by the shortest distance to the irradiation site is no more than 1 mm.

9. An apparatus according to claim 1, wherein a distance between a center of an irradiation site and a center of a detection site forming one of said at least two light paths is no greater than 30 mm.

10. An apparatus according to claim 1, wherein a distance between a center of an irradiation site and a center of a detection site forming one of said at least two light paths is no greater than 15 mm.

11. An apparatus according to claim 1, wherein a distance between a center of an irradiation site and a center of a detection site forming one of said at least two light paths is no greater than 10 mm.

12. An apparatus according to claim 1, wherein the detection site has a long, narrow configuration such that a length thereof is significantly greater than a width thereof.

13. An apparatus according to claim 12, wherein said detection site at least partially surrounds the irradiation site in an arcuate equidistant configuration.

14. An apparatus according to claim 1, wherein at least one of a set of at least three irradiation means and a set of at least three detection means are provided, and configured wherein at least three different light paths are formed between respective pairings of corresponding irradiation means and detection means.

15. An apparatus according to claim 1, wherein at least two irradiation means are provided for irradiating primary light at different irradiation sites and at least two detection means are provided for detecting secondary light emerging at different detection sites, said irradiation means and said detection means being configured wherein at least two pairings of corresponding irradiation means and corresponding detection means are provided for each of at least two different distances between the corresponding irradiation sites and the corresponding detection sites.

16. An apparatus according to claim 1, wherein said detection means comprises a light receiver located in a light transmission area of a skin contact element.

17. An apparatus according to claim 16, comprising a plurality of said detection means, said plurality of detection means being attached to the skin contact element forming a two-dimensional arrangement of photosensitive elements.

18. An apparatus according to claim 1, wherein said irradiation means comprises a semiconductor light emitter located in a light-transmission area of a skin contact element.

19. An apparatus according to claim 1, wherein said data processing means converts the measurement signals into the signal corresponding to the glucose concentration based upon a dependence of an intensity of the measurement signals in the at least two detection measurements upon a relative position of the irradiation site and detection site in the at least two detection measurements.

20. An apparatus according to claim 19, wherein said data processing means separates absorption and scattering of said primary light as factors which influence the intensity of the measurement signals in the at least two detection measurements, said data processing means separating the absorption and scattering based upon an intensity profile of the secondary light as a function of a measurement distance of the detection site from the irradiation site.

21. An apparatus according to claim 1, wherein the primary light irradiated by the irradiation means has a wavelength between 400 nm and 2500 nm.

22. An apparatus according to claim 21, wherein the wavelength of the primary light is between 400 nm and 600 nm.

23. An apparatus according to claim 21, wherein the wavelength of the primary light is between 750 nm and 920 nm.

24. An apparatus according to claim 23, wherein the wavelength of the primary light is between 780 nm and 825 nm.

25. An apparatus according to claim 23, wherein the wavelength of the primary light is between 850 and 900 nm.

26. An apparatus according to claim 21, wherein the wavelength of the primary light is between 1050 nm and 1350 nm.

27. An apparatus according to claim 21, wherein the wavelength of the primary light is between 1200 nm and 1300 nm.

28. An apparatus according to claim 21, wherein the wavelength of the primary light is between 1600 nm and 1800 nm.

29. An apparatus according to claim 28, wherein the wavelength of the primary light is between 1630 nm and 1770 nm.

30. An apparatus according to claim 29, wherein the wavelength of the primary light is between 1630 nm and 1670 nm.

31. An apparatus according to claim 29, wherein the wavelength of the primary light is between 1730 nm and 1770 nm.

32. An apparatus according to claim 1, wherein the primary light irradiated by the irradiation means has a wavelength in a spectral region wherein glucose concentration has a minimal effect on the optical absorption coefficient of the biological matrix.