Methods of using Raman spectral information in determining analyte concentrations

• US 8,452,365 B2
• Filed: 05/24/2006
• Issued: 05/28/2013
• Est. Priority Date: 05/25/2005
• Status: Active Grant

• Current Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation)
• Original Assignee: Bayer Healthcare LLC (Bayer AG)
• Inventors: Rebec, Mihailo V., Houlne, Michael P.
• Primary Examiner(s): HINDENBURG, MAX F
• Application Number:
  US11/920,599
• Publication Number:
  US 20090177052A1
• Time in Patent Office: 2,561 Days
• Field of Search: 600/310, 600/335, 600/322
• US Class Current: 600/335
• CPC Class Codes: A61B 2562/0238 Optical sensor arrangements for performing transmission measurements on body tissue
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: G01N 21/65 Raman scattering
• CPC Class Codes: G01N 21/658 enhancement Raman, e.g. surface plasmons
• CPC Class Codes: G01N 2201/0668 Multiple paths; optimisable path length

Abstract

A non-invasive method of determining the concentration of an analyte uses Raman spectral information. A high-intensity, narrow band of light (10) is applied to one side (12a) of skin tissue (12). The high-intensity light (10) enters the skin tissue and generates a Raman signal (16). A reflective material (22) is placed in a location nearest the other side (12b) of skin tissue (12). The reflective material (22) is located generally opposite of the entry (A) of the applied high-intensity light (10). The high-intensity light (10) and the Raman signal (20) that pass through the skin tissue (12) are reflected back into the skin tissue (12) via the reflective material (22). The Raman signal (16,20) is collected and the analyte concentration is determined using the collected Raman signal (16,20).

Claims

1. A non-invasive method of determining the concentration of an analyte using Raman spectral information, the method comprising the acts of:

pinching an area of skin tissue;

placing a reflective material near or around the pinched skin tissue, the reflective material forming at least one opening therethrough;

applying a high-intensity, narrow band of light to the skin tissue through the at least one opening, the high-intensity light entering the pinched skin tissue and generating a Raman signal;

reflecting the high-intensity light and Raman signal that pass through the pinched skin tissue back into the pinched skin tissue via the reflective material;

collecting the Raman signal; and

determining the analyte concentration using the collected Raman signal, wherein the Raman signal is collected at a wavelength range of from about 300 to about 5000 nm.

2. The method of claim 1, wherein the reflective material forms a plurality of openings therethrough and the high-intensity light is applied through the plurality of openings.

3. The method of claim 1, wherein the Raman signal is collected via high NA (numerical aperture) optics or fiber(s).

4. The method of claim 1, wherein the reflective material comprises aluminum.

5. The method of claim 1, wherein the Raman signal is collected at a wavelength range of from about 830 to about 1030 nm.

6. The method of claim 1, wherein the Raman signal is collected via high NA (numerical aperture) optics or fiber(s).

7. The method of claim 1, wherein the high-intensity light is applied from a monochromatic light source.

8. The method of claim 7, wherein the high-intensity light is applied from a laser diode source.

9. The method of claim 1, wherein the reflective material comprises a gold-plated surface.

10. The method of claim 1, further including a detector that assists in determining the analyte concentration, the detector being a silicon detector.

11. The method of claim 1, further including a detector that assists in determining the analyte concentration, the detector being a germanium detector.

12. The method of claim 1, further including a detector that assists in determining the analyte concentration, the detector being an InGaAs detector.

13. The method of claim 1, further including a detector that assists in determining the analyte concentration, the detector being a lead sulfide detector.