Optical-based sensing devices

• US 7,016,714 B2
• Filed: 02/24/2004
• Issued: 03/21/2006
• Est. Priority Date: 08/26/1998
• Status: Expired due to Term

• Current Assignee: Senseonics, Incorporated (Senseonics Holdings, Inc.)
• Original Assignee: Sensors For Medicine and Science Incorporated
• Inventors: Colvin, Arthur E. Jr.
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US10/784,731
• Publication Number:
  US 20040176669A1
• Time in Patent Office: 756 Days
• Field of Search: 600/316, 600/317, 128/899
• US Class Current: 600/316
• CPC Class Codes: A61B 2560/0219 of externally powered implanted units
• CPC Class Codes: A61B 2562/12 Manufacturing methods specially adapted for producing sensors for in-vivo measurements
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/6861 Capsules, e.g. for swallowing or implanting
• CPC Class Codes: G01N 2021/7773 Reflection
• CPC Class Codes: G01N 2021/7783 Transmission, loss
• CPC Class Codes: G01N 2021/7786 Fluorescence
• CPC Class Codes: G01N 21/552 Attenuated total reflection
• CPC Class Codes: G01N 21/6428 Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" in vivo A61B5/00; immunoassay G01N33/53
• CPC Class Codes: G01N 21/648 using evanescent coupling or surface plasmon coupling for the excitation of fluorescence
• CPC Class Codes: G01N 21/77 by observing the effect on a chemical indicator
• CPC Class Codes: G01N 21/7703 using reagent-clad optical fibres or optical waveguides using measurement of total internal reflection or attenuated total reflection G01N21/552; optical fibres or waveguides per se G02B
• CPC Class Codes: G01N 33/54373 involving physiochemical end-point determination, e.g. wave-guides, FETS, gratings
• CPC Class Codes: Y10S 128/903 Radio telemetry

Abstract

An optical-based sensor for detecting the presence or amount of an analyte using both indicator and reference channels. The sensor has a sensor body with a source of radiation embedded therein. Radiation emitted by the source interacts with indicator membrane indicator molecules proximate the surface of the body. At least one optical characteristic of these indicator molecules varies with analyte concentration. For example, the level of fluorescence of fluorescent indicator molecules or the amount of light absorbed by light-absorbing indicator molecules can vary as a function of analyte concentration. In addition, radiation emitted by the source also interacts with reference membrane indicator molecules proximate the surface of the body. Radiation (e.g., light) emitted or reflected by these indicator molecules enters and is internally reflected in the sensor body. Photosensitive elements within the sensor body generate both indicator channel and reference channel signals to provide an accurate indication of the concentration of the analyte. Preferred embodiments are totally self-contained and are sized and shaped for use in vivo in a human being. Such embodiments preferably include a power source, e.g. an inductor, which powers the source of radiation using external means, as well as a transmitter, e.g. an inductor, to transmit to external pickup means the signal representing the level of analyte.

Claims

1. An optical-based sensor for determining the presence or concentration of an analyte in a medium, said sensor comprising:

a substrate, said substrate having a first side and a second side, the first and second sides having regions that are masked;

a first radiation source mounted on the first side of said substrate;

a second radiation source mounted on the second side of said substrate;

a first detector for detecting radiation incident thereon and generating an electrical signal responsive thereto, said first detector mounted on the first side of said substrate;

a second detector for detecting radiation incident thereon and generating an electrical signal responsive thereto, said second detector mounted on the second side of said substrate;

a first indicator element having an optical characteristic that is affected by the presence or concentration of an analyte, said first indicator element being positioned to receive radiation from said first radiation source;

a second indicator element having an optical characteristic that is affected by the presence or concentration of an analyte, said second indicator element being positioned to receive radiation from said second radiation source; and

wherein said first detector generates an electrical signal responsive to radiation incident thereon emitted by said first indicator element and wherein said second detector generates an electrical signal responsive to radiation incident thereon emitted by said second indicator element.

2. The sensor of claim 1, wherein said first and second radiation sources are LEDs.

3. The sensor of claim 1, wherein said sensor has a sensor body, said sensor body having an outer surface surrounding said sensor body.

4. The sensor of claim 3, wherein said first indicator element includes indicator molecules disposed within an indicator membrane proximate the outer surface of said sensor body, said indicator membrane containing indicator molecules that are affected by the presence or concentration of an analyte and positioned to receive radiation from said radiation source.

5. The sensor of claim 4, wherein said second indicator element includes indicator molecules disposed within an indicator membrane proximate the outer surface of said sensor body, said indicator membrane containing indicator molecules that are affected by the presence or concentration of an analyte and positioned to receive radiation from said radiation source.

6. The sensor of claim 5, wherein said indicator molecules from said first and second indicator elements are affected by the presence or concentration of analytes that are different from one another.

7. The sensor of claim 4, wherein the optical characteristics of said indicator molecules vary as a function of the concentration of oxygen.

8. The sensor of claim 4, wherein the optical characteristics of said indicator molecules vary as a function of the concentration of glucose.

9. The sensor of claim 3, wherein said second indicator element includes a reference membrane disposed proximate the outer surface of said sensor body and positioned to receive radiation from said radiation source, said reference membrane containing indicator molecules that are substantially unaffected by the presence or concentration of an analyte.

10. The sensor of claim 3, wherein said second indicator element includes indicator molecules disposed within an indicator membrane proximate the outer surface of said sensor body, said indicator membrane containing indicator molecules that are affected by the presence or concentration of an analyte and positioned to receive radiation from said radiation source.

11. The sensor of claim 3, wherein said sensor body is configured such that some of the radiation received by either said first or second photosensitive elements is reflected internally within said sensor body before striking the photosensitive elements.

12. The sensor of claim 3, wherein said sensor body is an optically transmissive sensor body which functions as an optic wave guide.

13. The sensor of claim 1, wherein said first radiation source and said second radiation source are mounted on opposite sides of said substrate.

14. The sensor of claim 1, wherein said first radiation source and said second radiation source are mounted on the masked regions of the first and second sides of said substrate.

15. An optical-based sensor for determining the presence or concentration of an analyte in a medium, said sensor comprising:

a sensor body having an outer surface surrounding the sensor body;

a substrate, said substrate having a first side and a second side;

a first radiation source mounted on the first side of said substrate;

a second radiation source mounted on the second side of said substrate;

a first detector for detecting radiation incident thereon and generating and electrical signal responsive thereto, said first detector mounted on the first side of said substrate;

a second detector for detecting radiation incident thereon and generating and electrical signal responsive thereto, said second detector mounted on the second side of said substrate;

a first indicator element having an optical characteristic that is affected by the presence or concentration of an analyte, said first indicator element being positioned to receive radiation from said first radiation source, said first indicator element including indicator molecules disposed within an indicator membrane proximate the outer surface of said sensor body, said indicator membrane containing indicator molecules that are affected by the presence or concentration of an analyte and positioned to receive radiation from said radiation source;

a second indicator element having an optical characteristic that is affected by the presence or concentration of an analyte, said second indicator element being positioned to receive radiation from said second radiation source, said second indicator element including indicator molecules disposed within an indicator membrane proximate the outer surface of said sensor body, said indicator membrane containing indicator molecules that are affected by the presence or concentration of an analyte and positioned to receive radiation from said radiation source; and

wherein said first detector generates an electrical signal responsive to radiation incident thereon emitted by said first indicator element and wherein said second detector generates an electrical signal responsive to radiation incident thereon emitted by said second indicator element, and

wherein said indicator molecules from said first and second indicator elements are affected by the presence or concentration of analytes that are different from one another.

16. The sensor of claim 15, wherein said first and second radiation sources are LEDs.

17. The sensor of claim 15, wherein said second indicator element includes a reference membrane disposed proximate the outer surface of said sensor body and positioned to receive radiation from said radiation source, said reference membrane containing indicator molecules that are substantially unaffected by the presence or concentration of an analyte.

18. The sensor of claim 15, wherein said second indicator element includes indicator molecules disposed within an indicator membrane proximate the outer surface of said sensor body, said indicator membrane containing indicator molecules that are affected by the presence or concentration of an analyte and positioned to receive radiation from said radiation source.

19. The sensor of claim 15, wherein the optical characteristics of one of said indicator molecules varies as a function of the concentration of oxygen.

20. The sensor of claim 15, wherein the optical characteristics of one of said indicator molecules varies as a function of the concentration of glucose.

21. The sensor of claim 15, wherein said first radiation source and said second radiation source are mounted on opposite sides of said substrate.

22. The sensor of claim 15, wherein said sensor body is configured such that some of the radiation received by either said first or second photosensitive elements is reflected internally within said sensor body before striking the photosensitive elements.

23. The sensor of claim 15, wherein said sensor body is an optically transmissive sensor body which functions as an optic wave guide.

24. The sensor of claim 23, wherein said first side of said substrate and said second side of said substrate contain regions that are masked.

25. The sensor of claim 24, wherein said first radiation source and said second radiation source are mounted on the masked regions of the first and second sides of said substrate.