SYSTEMS, DEVICES AND METHODS FOR IN SITU CALIBRATION OF IMPLANTABLE SENSORS

• US 20140371553A1
• Filed: 12/17/2012
• Published: 12/18/2014
• Est. Priority Date: 12/16/2011
• Status: Active Grant

• Current Assignee: James Winkelman
• Original Assignee: James Winkelman
• Inventors: Winkelman, James
• Granted Patent: US 10,010,274 B2
• Time in Patent Office: Days
• US Class Current: 600/316
• CPC Class Codes: A61B 2560/0228 using calibration standards
• CPC Class Codes: A61B 5/14503 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors A61B5/1459, A61B5/1464, A61B5/1473, A61B5/1482, A61B5/14865 take precedence
• 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 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes

Abstract

The systems, methods, and devices described herein generally involve monitoring and/or quantification of various analyte levels in a biological fluid using one or more implantable sensors. In various aspects, systems, methods, and devices described herein can provide for the in situ calibration and/or cleaning of such sensors when implanted in the patient. The systems and devices disclosed herein can, for example, continuously or serially measure analytes within a biological fluid in vivo (e.g., without extracting the biological fluid from the patient) and periodically calibrate and/or clean the sensor without using finger sticks or additional, invasive calibration techniques. By way of non-limiting example, systems and devices disclosed herein can enable continuous monitoring of analyte concentrations (e.g., glucose) in subcutaneous interstitial fluid for several hours to a few days.

Claims

1. A system for monitoring the concentration of an analyte, comprising:

a sensor configured to be implanted at an implant site in a patient'"'"'s skin, said sensor sensing an analyte present in a biological fluid at the implant site;

a reservoir containing a calibration fluid having a known concentration of said analyte; and

a conduit for delivering said calibration fluid from the reservoir to the implant site.

2. The system of claim 1, wherein the biological fluid comprises subcutaneous interstitial fluid.

3. The system of claim 1, wherein the analyte comprises glucose.

4. The system of claim 1, wherein said sensor extends to a depth below the skin surface from a housing configured to be disposed on the skin surface.

5. The system of claim 4, wherein the sensor comprises a microneedle extending from the housing, said microneedle configured to pierce the skin.

6. The system of claim 4, wherein the sensor extends through a fluid pathway defined by said conduit.

7. The system of claim 6, wherein the conduit comprises a sheath enclosing a distal end of the sensor and wherein the calibration solution is delivered to the implant site in the fluid pathway between the sheath and the sensor.

8. The system of claim 4, wherein the conduit and sensor extend from the housing adjacent to one another.

9. The system of claim 4, wherein the housing comprises a data processing unit.

10. The system of claim 4, wherein the housing comprises a transmitting unit.

11. The system of claim 4, wherein the reservoir is contained within said housing.

12. The system of claim 11, further comprising a pump contained within said housing, said pump for pumping said calibration fluid through said conduit.

13. The system of claim 12, further comprising a controller, said controller controlling the pump so as to deliver a predetermined amount of the calibration fluid to the implant site.

14. The system of claim 13, wherein the controller is configured to control the pump to deliver the predetermined amount of the calibration fluid to the implant site a predetermined number of times with a predetermined time interval.

15. The system of claim 13, wherein the controller controls a number of repetitions of calibration fluid delivery, an amount of the calibration fluid delivered, and a time interval between each delivery.

16. The system of claim 15, wherein the number of repetitions of calibration fluid delivery is 1 to 5, the amount of the calibration fluid delivered is from about 2 to about 50 microliters for each delivery, and the time interval between each delivery is from about 1 minute to about 24 hours.

17. The system of claim 1, wherein said sensor comprises one of an electrochemical sensor and an optical sensor.

18. The system of claim 1, wherein the sensor comprises one or more sensing sites.

19. The system of claim 18, wherein an outlet of the conduit is disposed relative to the one or more sensing sites such that fluid delivered by the conduit to the implant site is directed at the one or more sensing sites.

20. The system of claim 19, wherein the fluid delivered by the conduit is configured to remove contaminants from the one or more sensing sites.

21. A method of operating an implantable monitoring system, comprising:

delivering a calibration fluid of a known concentration to a sensor implanted at an implant site of a patient, said sensor configured to sense a parameter at the implant site; and

determining a calibration value following delivery of the calibration fluid to the implant site.

22-41. -41. (canceled)