Methods and materials for modulating start-up time and air removal in dry sensors

• US 9,989,522 B2
• Filed: 05/23/2012
• Issued: 06/05/2018
• Est. Priority Date: 11/01/2011
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Kristensen, Jesper Svenning, Dang, Tri T., Knarreborg, Katharine, Bansal, Anubhuti
• Primary Examiner(s): Bowers, Erin M.
• Application Number:
  US13/478,356
• Publication Number:
  US 20130109039A1
• Time in Patent Office: 2,204 Days
• Field of Search: None
• CPC Class Codes: A61B 2562/02 Details of sensors specially adapted for in-vivo measurements
• CPC Class Codes: A61B 2562/028 Microscale sensors, e.g. electromechanical sensors [MEMS]
• CPC Class Codes: A61B 2562/162 Capsule shaped sensor housings, e.g. for swallowing or implantation
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14556 by fluorescence A61B5/14555 takes precedence
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/6861 Capsules, e.g. for swallowing or implanting
• CPC Class Codes: G01N 21/77 by observing the effect on a chemical indicator
• CPC Class Codes: G01N 33/487 of liquid biological material
• CPC Class Codes: G01N 33/525 Multi-layer analytical elements

Abstract

The invention relates to sensors configured to include compositions disposed in specific regions of the sensor in order to provide the sensors with enhanced functional properties, for example faster start-up times. These compositions include, for example, hygroscopic compositions, gas generating compositions and gas solvating compositions. While typical embodiments of the invention pertain to glucose sensors, the systems, methods and materials disclosed herein can be adapted for use with a wide variety of sensors known in the art.

Claims

1. A method for decreasing a waiting time between placement of a sensor within an aqueous environment comprising an in vivo tissue and generation of a sensor signal that can be correlated with the concentration of a sensed analyte, the method comprising:

(a) selecting the sensor to be configured as a cylindrical fiber formed from a biocompatible polymeric material having a diameter of less than 1 mm and having an encapsulated longitudinal cavity disposed therein;

(i) an exterior surface and an internal matrix within the cavity comprising air and at least one sensing complex that senses analytes within aqueous environments;

(ii) a hygroscopic composition disposed on a surface within the cavity; and

(iii) carbonic anhydrase disposed on a surface within the cavity; and

(b) placing the sensor into an aqueous environment that comprises an in vivo tissue;

(c) allowing the hygroscopic composition to modulate hydration of the sensing complex; and

(d) generating a sensor signal that can be correlated with the concentration of the analyte following said hydration of the sensing complex;

wherein;

a waiting time between sensor placement in the aqueous environment and generation of a sensor signal that can be correlated with the concentration of the analyte is decreased by steps (a)-(d).

2. The method of claim 1, wherein the hygroscopic composition comprises a salt and a saccharide.

3. The method of claim 1, wherein the hygroscopic composition comprises a saccharide and a polyol.

4. The method of claim 1, wherein the hygroscopic composition comprises a saccharide, a polyol and a salt.

5. A method for decreasing a waiting time between placement of a glucose sensor within an aqueous environment comprising an in vivo tissue and generation of a sensor signal that is correlated with the concentration of glucose, the method comprising:

(a) selecting the sensor to be configured as a cylindrical fiber having a diameter of less than 1 mm and formed from a biocompatible polymeric material that allows the diffusion of glucose therethrough, wherein the cylindrical fiber;

(i) comprises an exterior sensor surface that contacts the aqueous environment comprising glucose; and

(ii) comprises an encapsulated longitudinal cavity having an internal surface with the following disposed thereon;

a sensing complex comprising a mannose binding lectin, wherein the sensing complex senses glucose that has diffused from the aqueous environment through the biocompatible polymeric material and into the encapsulated longitudinal cavity;

a hygroscopic composition; and

carbonic anhydrase; and

(b) placing the sensor into an aqueous environment that comprises glucose;

(c) allowing the hygroscopic composition to modulate hydration of the sensing complex; and

(d) generating a sensor signal that is correlated with the concentration of glucose following said hydration of the sensing complex;

wherein;

a waiting time between sensor placement in the aqueous environment and generation of a sensor signal that can be correlated with the concentration of glucose is decreased by steps (a)-(d).

6. The method of claim 5, wherein the hygroscopic composition comprises a saccharide.

7. The method of claim 6, wherein the hygroscopic composition comprises sucrose.

8. The method of claim 7, wherein the hygroscopic composition further comprises a polyol.

9. The method of claim 8, wherein the hygroscopic composition further comprises a salt.

10. The method of claim 5, wherein the sensing complex further comprises a fluorophore.

11. The method of claim 5, wherein the hygroscopic composition is irreversibly coupled to a fixed location within the cavity.

12. The method of claim 5, wherein the cavity further comprises at least one compound selected from the group consisting of NaHCO₃, Na₂CO₃, NH₄HCO₃, (NH₄)₂CO₃, KHCO₃ and K₂CO₃.

13. The method of claim 5, wherein the cavity further comprises an acidic excipient.

14. The method of claim 13, wherein the acidic excipient is citric acid.