INTRAVASCULAR GLUCOSE SENSOR

• US 20130072768A1
• Filed: 02/15/2011
• Published: 03/21/2013
• Est. Priority Date: 02/19/2010
• Status: Abandoned Application

• Current Assignee: Glysure Ltd
• Original Assignee: Glysure Ltd
• Inventors: Crane, Barry Colin, Cairns, Neil, Gilchrist, John
• Application Number:
  US13/579,010
• Publication Number:
  US 20130072768A1
• Time in Patent Office: Days
• US Class Current: 600/316
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: G01N 2021/772 Tip coated light guide
• CPC Class Codes: G01N 2021/7786 Fluorescence
• CPC Class Codes: G01N 21/6408 with measurement of decay time, time resolved fluorescence
• 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

Abstract

A glucose sensor for intravascular measurement of glucose concentration wherein the sensor is arranged to measure glucose concentration by monitoring the lifetime of the fluorophore, the sensor comprising:—an indicator system comprising a receptor for selectively binding to glucose and a fluorophore associated with said receptor, wherein the fluorophore has a life-time of less than 100 ns;—a light source;—an optical fibre arranged to direct light from the light source onto the indicator system; —a detector arranged to receive fluorescent light emitted from the indicator system; and—a signal processor arranged to determine information related to a fluorescence lifetime of the fluorophore based on at least the output signal of the detector.

Claims

1. A glucose sensor for intravascular measurement of glucose concentration wherein the sensor is arranged to measure glucose concentration by monitoring the lifetime of the fluorophore, the sensor comprising:

an indicator system comprising a receptor for selectively binding to glucose and a fluorophore associated with said receptor, wherein the fluorophore has a lifetime of less than 100 ns;

a light source;

an optical fibre arranged to direct light from the light source onto the indicator system;

a detector arranged to receive fluorescent light emitted from the indicator system; and

a signal processor arranged to determine information related to a fluorescence lifetime of the fluorophore based on at least the output signal of the detector.

2. A sensor according to claim 1, wherein the detector is a single photon avalanche diode.

3. A sensor according to claim 2, further comprising:

a driver arranged to modulate the light source intensity at a first frequency;

a bias voltage source arranged to apply a bias voltage to the single photon avalanche diode, wherein the bias voltage is modulated at a second frequency, different from the first frequency, and wherein the bias voltage is above the breakdown voltage of the single photon avalanche diode.

4. A sensor according to claim 3, wherein the signal processor operates on a component of the output signal of the single photon avalanche diode at a frequency given by the difference between the first and second frequencies.

5. A sensor according to claim 3, wherein a signal generator is controlled to vary at least one of:

the frequency difference between said first and second frequencies; and

the phase difference between signals at said first and second frequencies used to modulate the light source and modulate the bias voltage.

6. A sensor according to claim 1, wherein the indicator system comprises a fluorophore-receptor construct which is bound to a hydrogel.

7. A sensor according to claim 6, wherein the hydrogel is a fluid hydrogel having a water content of at least 30% w/w.

8. A sensor according to claim 1, wherein the indicator system is an aqueous solution in which the receptor and fluorophore are dissolved.

9. A sensor according to claim 1, wherein the fluorophore has a lifetime of 30 ns or less.

10. A sensor according to claim 1, wherein the fluorophore is a non-metallic fluorophore.

11. A method of intravascular measurement of glucose concentration comprising

inserting the indicator system of a sensor as defined in claim 1 or 6 to into a vein or artery;

passing incident light from the light source to the indicator system via the optical fibre;

receiving fluorescent light, emitted from the indicator system in response to the light incident on the indicator system from the light source, using the detector and generating an output signal; and

determining information related to the fluorescence lifetime of the fluorophore based on at least the output signal of the detector.

12. A method according to claim 10, wherein the detector is a single photon avalanche diode and the method further comprises the steps of:

modulating the light source intensity at a first frequency; and

applying a bias voltage to the single photon avalanche diode, wherein the bias voltage is modulated at a second frequency, different from the first frequency, and wherein the bias voltage is above the breakdown voltage of the single photon avalanche diode.

13. A method according to claim 12, comprising determining the fluorescence lifetime information based on a component of the output signal of the single photon avalanche diode at a frequency given by the difference between the first and second frequencies.

14. A method according to claim 12, further comprising at least one of:

varying the frequency difference between the first and second frequencies; and

controlling the phase difference between signals at said first and second frequencies used to modulate the light source and modulate the bias voltage.