Method of tissue modulation for noninvasive measurement of an analyte

• US 20030208169A1
• Filed: 01/13/2003
• Published: 11/06/2003
• Est. Priority Date: 07/11/2000
• Status: Active Grant

• Current Assignee: Lightouch Medical, Inc.
• Original Assignee: Lightouch Medical, Inc.
• Inventors: Petersen, Charles M, Peterson, Karen P, Chaiken, Joseph
• Granted Patent: US 7,050,842 B2
• Time in Patent Office: Days
• US Class Current: 604/310
• CPC Class Codes: A61B 5/0053 by applying pressure, e.g. compression, indentation, palpation, grasping, gauging
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• 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 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips

Abstract

Disclosed are a device and methods for obtaining signals related to blood analytes and bone features by collecting spectra, such as fluorescence and Raman spectra, through the nail of a finger or toe. The invention additionally provides methods of modulating blood flow in a tissue of a subject.

Claims

1. A method of noninvasive spectroscopic measurement of an analyte in a subject comprising:

(a) irradiating tissue of the subject through a nail with electromagnetic radiation having an excitation wavelength while the tissue is in a blood-replete state;

(b) collecting the spectra emitted by the tissue in the blood-replete state;

(c) applying a tissue modulation device having an orifice to the nail of the subject so as to achieve a blood-depleted state within the tissue;

(d) irradiating the tissue through the nail with electromagnetic radiation having an excitation wavelength while the tissue is in a blood-depleted state;

(e) collecting the spectra emitted by the tissue in the blood-depleted state; and

(f) analyzing the collected spectra to determine a concentration of analyte present in the tissue, wherein the analyzing comprises determining the difference between the spectra collected in the blood-replete and blood-depleted states.

6. The method of any one of claims 1 to 5, wherein the spectra are Raman spectra.

7. The method of any one of claims 1 to 6, wherein the nail is a fingernail.

8. The method of any one of claims 1 to 6, wherein the nail is a toenail.

9. The method of any one of claims 1 to 8, wherein the analyte comprises glucose.

10. The method of any one of claims 1 to 8, wherein the analyte comprises hydroxyapatite.

11. The method of claim 1 or 4, wherein the blood-replete state is achieved by hindering blood flow through an artery that serves the tissue.

12. The method of claim 1 or 4, wherein the blood-replete state is achieved by altering the temperature of the tissue.

13. The method of claim 12, wherein the temperature is altered by heating.

14. The method of claim 12, wherein the temperature is altered by cooling.

2. A method of noninvasive spectroscopic measurement of an analyte in a subject comprising:

(a) irradiating tissue of the subject through a nail with electromagnetic radiation having an excitation wavelength;

(b) collecting the spectra emitted by the tissue; and

(c) analyzing the collected spectra to determine a signal that is proportional to the amount of analyte present in the tissue.

3. The method of claim 2, further comprising analyzing spectra emitted by the tissue that are indicative of blood volume, and wherein the analyzing comprises determining the amount of analyte per unit blood volume.

4. The method of claim 3, wherein spectra are collected in blood-replete and in blood-depleted states, and the analyzing comprises determining the difference between the spectra collected in the blood-replete and blood-depleted states.

5. The method of claim 3 or 4, wherein the spectra indicative of blood volume comprise fluorescence, phosphorescence or absorption spectra.