Method and apparatus for non-invasive analysis of blood glucose

• US 20020193673A1
• Filed: 06/24/2002
• Published: 12/19/2002
• Est. Priority Date: 12/28/1999
• Status: Active Grant

• Current Assignee: RF Science & Technology, Inc.
• Original Assignee: Pindi Products, Inc.
• Inventors: Fuller, Milton E.
• Granted Patent: US 6,723,048 B2
• Time in Patent Office: Days
• US Class Current: 600/365
• CPC Class Codes: A61B 5/05 Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves impedance plethysmography A61B5/0295; measuring movement of the entire body or parts thereof A61B5/11; detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof A61B5/24
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: H01F 7/0273 Magnetic circuits with PM for magnetic field generation

Abstract

The present invention provides apparatus for non-invasive detection and quantitation of analytes in a sample, such as blood glucose. The apparatus employs a novel amplifier that uses high-gauss permanent magnets (12, 14) to permit an Rf signal to be transmitted through the sample (116). The concentration of the analyte can be determined from the magnitude of the reduction in the amplitude of the Rf signal at a characteristic frequency.

Claims

1. An apparatus for substantially noise-free transmission of an Rf signal comprising:

(a) a plurality of spaced-apart permanent magnets that generate a magnetic field;

(b) at least one transmission node, and at least one reflection node spaced apart from the transmission node with a gap therebetween, that are disposed within the magnetic field, the transmission and reflection nodes comprised of an electrically-conductive material; and

(c) a source that generates an Rf signal having a selected frequency spectrum that is connected to the transmission node and reflection node, such that a detectable Rf signal is received by the reflection node.

2. The apparatus of claim 1 wherein the permanent magnets are each grade 26 to grade 60 magnets.

3. The apparatus of claim 2 wherein the permanent magnets are each grade 36 to 41.

4. The apparatus of claim 2 wherein the permanent magnets are each NdFeB magnets.

5. The apparatus of claim 1 wherein the transmission node and reflection node are each in close proximity to one of the magnets.

6. The apparatus of claim 5 comprising a magnetically permeable and electrically insulating barrier disposed between each node and said magnet in close proximity thereto to prevent contact therebetween.

7. The apparatus of claim 1 wherein the source produces an Rf signal having a frequency of about 2 GHz to about 3 GHz.

8. The apparatus of claim 1 further comprising an analyzer connected to the transmission node and the reflection node that analyzes the Rf signal received by the reflection node.

9. The apparatus of claim 8 further comprising a space or receptacle between the transmission node and reflection mode for receiving a sample comprising an analyte, such that an Rf signal having a magnitude at a characteristic frequency is detectable by the analyzer when the sample is placed in the space or receptacle, the magnitude at the characteristic frequency is reduced as a function of analyte concentration.

10. The apparatus of claim 9 wherein the sample is a biological sample.

11. The apparatus of claim 10 wherein the sample is a bodily fluid, tissue, or body part.

12. The apparatus of claim 11 wherein the sample is a finger.

13. The apparatus of claim 9 wherein the analyte is a biological molecule.

14. The apparatus of claim 13 wherein the analyte is glucose.

17. The method of claim 16 further comprising (i) determining the reduction of the amplitude of the Rf signal at the frequency that is characteristic of the presence of the analyte, and (ii) determining the concentration of the analyte on the basis of said reduction of the amplitude.

15. A method of causing an Rf signal to be transmitted between spaced-apart transmission and reflection nodes, the method comprising:

(a) providing at least one transmission node, and at least one reflection node spaced apart from the transmission node with a gap therebetween, the transmission and reflection nodes comprised of an electrically-conductive material, and, connected to the transmission node and a reflection node, a source that generates an Rf signal having a selected frequency spectrum;

(b) disposing the transmission node and the reflecting node in a magnetic field produced by a plurality of spaced-apart high gauss permanent magets.

16. A method for detecting an analyte in a sample comprising:

(a) providing an apparatus comprising (i) a plurality of spaced-apart permanent magnets that generate a magnetic field;

(ii) at least one transmission node, and at least one reflection node spaced apart from the transmission node with a gap therebetween, that are disposed within the magnetic field, the transmission and reflection nodes comprised of an electrically-conductive material;

(iii) a source that generates an Rf signal having a selected frequency spectrum that is connected to the transmission node and reflection node; and

(iv) an analyzer connected to the transmission node and reflection node;

(b) disposing a sample comprising an analyte between the transmission node and reflection node; and

(c) using the analyzer to detect a reduction in the amplitude of the Rf signal at a frequency that is characteristic of the presence of the analyte.