Calibration Methods for a Bandage-Type Analyte Sensor

• US 20170000390A1
• Filed: 07/02/2015
• Published: 01/05/2017
• Est. Priority Date: 07/02/2015
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Verily Life Sciences LLC (Alphabet Inc.)
• Inventors: Biederman, William James, Otis, Brian, Wasson, Jaclyn Leverett, Liu, Zenghe
• Granted Patent: US 10,765,353 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0238 Means for recording calibration data
• CPC Class Codes: A61B 2560/0412 Low-profile patch shaped housings
• CPC Class Codes: A61B 2562/164 the sensor is mounted in or on a conformable substrate or carrier
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/14514 using means for aiding extraction of interstitial fluid, e.g. microneedles or suction
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• 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
• CPC Class Codes: A61B 5/6801 specially adapted to be attached to or worn on the body surface
• CPC Class Codes: A61B 5/6833 Adhesive patches
• CPC Class Codes: A61B 5/6848 Needles
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61B 5/7475 User input or interface means, e.g. keyboard, pointing device, joystick

Abstract

A flexible, body-mountable analyte sensing device includes a flexible substrate configured for mounting to skin of a living body. The sensing device additionally includes a sensor probe attached to the flexible substrate and configured to penetrate the skin such that a sensor disposed on the end of the sensor probe can be exposed to an analyte in interstitial fluid. The sensor could be an electrochemical sensor that includes two or more electrodes disposed at the end of the sensor probe and configured to electrochemically detect the analyte. The sensing device is configured to display detected concentrations or other information about the analyte in the interstitial fluid. The flexible substrate of the sensing device is configured to be adhered or otherwise mounted to the skin in a manner that minimally impacts activities of the living body.

Claims

1. A body-mountable device comprising:

a flexible substrate, wherein the flexible substrate is configured to be mounted to a skin surface;

a sensor configured to generate an electrical signal, wherein the electrical signal is related to a physiological property;

an analog-to-digital converter, wherein the analog-to-digital converter is configured to receive the electrical signal generated by the sensor and to generate digital codes related to the received electrical signal, wherein the analog-to-digital converter is disposed on the flexible substrate; and

a controller operably coupled to the analog-to-digital converter, wherein the controller is disposed on the flexible substrate, wherein the controller is configured to perform controller operations comprising;

obtaining calibration data;

operating the sensor to generate a plurality of samples of the electrical signal related to the physiological property;

operating the analog-to-digital converter to generate a plurality of digital codes corresponding to respective samples of the electrical signal generated by the sensor;

recording the generated plurality of digital codes;

determining that a trigger condition is met; and

determining, responsive to determining that the trigger condition is met, at least one value of the physiological property based on at least one recorded digital code and the calibration data.

2. The body-mountable device of claim 1, further comprising:

a sensor probe, wherein a first end of the sensor probe is attached to the flexible substrate, wherein a second end of the sensor probe is configured to extend beneath the skin surface to contact interstitial fluid, and wherein the electrical signal generated by the sensor is related to an analyte in the interstitial fluid.

3. The body-mountable device of claim 2, further comprising a flexible battery disposed on the flexible substrate, wherein the flexible battery is configured to supply power to the controller.

4. The body-mountable device of claim 1, wherein the sensor comprises an electrochemical sensor.

5. The body-mountable device of claim 1, further comprising a user interface, wherein determining that a trigger condition is met comprises receiving an input via the user interface, and wherein the controller operations further comprise using the user interface to provide an indication related to the determined at least one value of the physiological property responsive to determining that the trigger condition is met.

6. The body-mountable device of claim 1, further comprising a user interface, wherein obtaining calibration data comprises:

using the user interface to receive an input; and

determining the calibration data based on the received input.

7. The body-mountable device of claim 1, further comprising an antenna, wherein determining that a trigger condition is met comprises receiving a communication from an external system via the antenna, and wherein the controller operations further comprise using the antenna to provide an indication related to the determined at least one value of the physiological property to the external system responsive to determining that the trigger condition is met.

8. The body-mountable device of claim 1, further comprising an antenna, wherein the antenna is configured to receive radio frequency energy to power the body-mountable device, and wherein determining that a trigger condition is met comprises receiving radio frequency energy to power the body-mountable device via the antenna.

9. The body-mountable device of claim 1, further comprising an antenna, wherein obtaining calibration data comprises:

using the antenna to receive a communication from an external system; and

determining the calibration data based on the received communication.

10. The body-mountable system of claim 1, wherein the body-mountable system uses less than approximately 1 microwatt of power during the first period of time.

11. A method comprising:

operating a body-mountable device, wherein the body-mountable device comprises;

a flexible substrate, wherein the flexible substrate is configured to be mounted to a skin surface;

a sensor configured to generate an electrical signal, wherein the electrical signal is related to a physiological property;

an analog-to-digital converter, wherein the analog-to-digital converter is configured to receive the electrical signal generated by the sensor and to generate digital codes related to the received electrical signal, wherein the analog-to-digital converter is disposed on the flexible substrate; and

a controller operably coupled to the analog-to-digital converter, wherein the controller is disposed on the flexible substrate;

wherein the operating comprises;

obtaining, by the controller, calibration data;

generating, by the controller operating the sensor, a plurality of samples of the electrical signal related to the physiological property;

generating, by the controller operating the analog-to-digital converter, a plurality of digital codes corresponding to respective samples of the electrical signal generated using the sensor;

recording, by the controller, the generated plurality of digital codes;

determining, by the controller, that a trigger condition is met; and

determining, by the controller responsive to determining that the trigger condition is met, at least one value of the physiological property based on at least one recorded digital code and the calibration data.

12. The method of claim 11, wherein the sensor of the body-mountable device comprises an electrochemical sensor.

13. The method of claim 11, wherein the body-mountable device further comprises:

a sensor probe, wherein a first end of the sensor probe is attached to the flexible substrate, wherein a second end of the sensor probe is configured to extend beneath the skin surface to contact interstitial fluid, and wherein the electrical signal generated by the sensor is related to an analyte in the interstitial fluid.

14. The method of claim 11, wherein the body-mountable device further comprises a user interface, wherein determining that a trigger condition is met comprises receiving, by the controller via the user interface, an input, and wherein the operating further comprises:

providing, by the controller using the user interface responsive to determining that the trigger condition is met, an indication related to the determined at least one value of the physiological property.

15. The method of claim 14, wherein the body-mountable device further comprises a user interface, and wherein obtaining calibration data comprises:

receiving, by the controller using the user interface, an input; and

determining, by the controller, the calibration data based on the received input.

16. The method of claim 11, wherein the body-mountable device further comprises an antenna, and wherein determining that a trigger condition is met comprises receiving, by the controller via the antenna, a communication from an external system, and wherein the operating further comprises:

providing, by the controller using the antenna responsive to determining that the trigger condition is met, an indication related to the determined at least one value of the physiological property to the external system.

17. The method of claim 11, wherein the body-mountable device further comprises an antenna, wherein the antenna is configured to receive radio frequency energy to power the body-mountable device, and wherein determining that a trigger condition is met comprises receiving radio frequency energy to power the body-mountable device via the antenna.

18. The method of claim 14, wherein the body-mountable device further comprises an antenna, and wherein obtaining calibration data comprises:

receiving, by the controller using the antenna, a communication from an external system; and

determining, by the controller, the calibration data based on the received communication.

19. The method of claim 11, wherein the calibration data comprise first calibration data corresponding to the operation of the body-mountable device at a first point in time and second calibration data corresponding to the operation of the body-mountable device at a second point in time, and wherein determining at least one value of the physiological property based on at least one recorded digital code and the calibration data comprises determining the at least one value of the physiological property based on a relative timing between the first and second points in time and a timing of generation of the at least one recorded digital code.

20. A body-mountable device comprising:

a flexible substrate, wherein the flexible substrate is configured to be mounted to a skin surface;

a sensor configured to generate an electrical signal, wherein the electrical signal is related to a physiological property;

an analog-to-digital converter, wherein the analog-to-digital converter is configured to receive the electrical signal generated by the sensor and to generate digital codes related to the received electrical signal, wherein the analog-to-digital converter is disposed on the flexible substrate;

a communications interface, wherein the communications interface is disposed on the flexible substrate; and

a controller operably coupled to the analog-to-digital converter, wherein the controller is disposed on the flexible substrate, wherein the controller is configured to perform controller operations comprising;

operating the sensor, during a first period of time, to generate at least one sample of the electrical signal related to the physiological property;

operating the analog-to-digital converter, during the first period of time, to generate at least one digital code corresponding to the respective at least one sample of the electrical signal generated by the sensor;

transmitting, using the communications interface, an indication of the generated at least one digital code to an external system;

receiving, using the communications interface, information indicating a specified set of digital codes from the external system;

operating the sensor, during a second period of time, to generate a plurality of samples of the electrical signal related to the physiological property;

operating the analog-to-digital converter, during the second period of time, to generate a plurality of digital codes corresponding to respective samples of the electrical signal generated by the sensor;

determining whether each of the generated plurality of digital codes corresponds to a digital code of the specified set of digital codes; and

responsive to determining that a particular generated digital code corresponds to a digital code of the specified set of digital codes, providing an alert indication.