Systems, devices, and methods related to the individualized calibration and/or manufacturing of medical devices
Systems, devices, kits, and methods are provided herein in the form of example embodiments that relate to calibration of medical devices. The medical devices can be sensors adapted to sense a biochemical attribute. The embodiments can be used to determine calibration information specific to an individual medical device. The embodiments can determine the calibration information by reference to one or more parameters obtained during manufacturing of the medical device. The embodiments can also determine the calibration information by reference to in vitro testing of the medical devices. The embodiments also apply to systems incorporating those medical devices in their use in the field. Also described are embodiments of modifications to surfaces of sensor substrates, such as through applied radiation and/or the creation of a well, to aid in the placement and/or sizing of a sensor element on the substrate.
1 . A continuous glucose monitoring system, comprising:
an on-body unit including:
a waterproof housing encasing sensor electronics including
a non-transitory memory,
a battery, and
an on-body-unit antenna, and
a transcutaneous sensor having a first portion configured to remain above a skin surface of a user and electrically coupled to the sensor electronics, and a second portion positionable beneath the skin surface of the user in a subcutaneous space and configured to generate a signal associated with a glucose level, wherein the second portion includes:
a working electrode,
a sensing region, including glucose oxidase, disposed over the working electrode, and
a glucose flux modulating layer disposed over the working electrode, and
an identifier physically associated with the transcutaneous sensor to uniquely identify the transcutaneous sensor during manufacturing; and
a receiver unit including a receiver antenna configured to communicate with the on-body-unit antenna via a communication link;
wherein at least one calibration parameter is stored on the non-transitory memory, the at least one calibration parameter is determined prior to distribution and based at least in part on an in vitro sensitivity of the transcutaneous sensor, and wherein the in vitro sensitivity of the transcutaneous sensor is determined prior to distribution and based at least in part on a Bayesian regression model having a first input comprising a representation of an individualized manufacturing parameter of the sensor, a second input comprising a representation of a baseline in vitro sensing characteristic of a baseline subset, and an output comprising the in vitro sensitivity of the transcutaneous sensor; and
wherein the sensor electronics are configured to calibrate the signal generated by the transcutaneous sensor using the at least one calibration parameter.
2 . The continuous glucose monitoring system of claim 1 , wherein the second portion comprises a sensing region and the individualized manufacturing parameter comprises the size of the sensing region.
3 . The continuous glucose monitoring system of claim 2 , wherein the size of the sensing region is representative of a width of the sensing region.
4 . The continuous glucose monitoring system of claim 2 , wherein the size of the sensing region is representative of a length of the sensing region.
5 . The continuous glucose monitoring system of claim 2 , wherein the size of the sensing region is representative of a thickness of the sensing region.
6 . The continuous glucose monitoring system of claim 1 , wherein the individualized manufacturing parameter comprises a thickness of the glucose flux modulating layer.
7 . The continuous glucose monitoring system of claim 6 , wherein the individualized manufacturing parameter comprises a thickness of an interferent-eliminating layer disposed over the working electrode and a thickness of the glucose flux modulating layer.
8 . The continuous glucose monitoring system of claim 1 , wherein the at least one calibration parameter is determined using at least a first multiple variable regression model.
9 . The continuous glucose monitoring system of claim 1 , wherein the glucose monitoring system does not require user calibration or automated system calibration based on independent analyte measurements provided to the glucose monitoring system.
10 . The continuous glucose monitoring system of claim 1 , wherein the glucose monitoring system is configured to receive user calibration using an independent analyte measurement provided to the glucose monitoring system.
11 . The continuous glucose monitoring system of claim 1 , wherein the second portion is non-planar and comprises a working electrode and a counter electrode separated by non-conductive material.
12 . The continuous glucose monitoring system of claim 1 , wherein the communication link is configured for bi-directional communication.
13 . The continuous glucose monitoring system of claim 1 , wherein the communication link uses a Bluetooth enabled communication protocol.
14 . The continuous glucose monitoring system of claim 1 , wherein the communication link uses a Near Field Communication (NFC) protocol.
15 . The continuous glucose monitoring system of claim 1 , wherein the receiver antenna communicates with the on-body-unit antenna according to a fix data communication schedule.
16 . The continuous glucose monitoring system of claim 1 , wherein the receiver antenna communicates with the on-body-unit antenna according to a dynamic data communication schedule.
17 . The continuous glucose monitoring system of claim 1 , wherein the second portion includes an active area, and wherein the glucose flux modulating layer is disposed over the active area to limit the flux of glucose to the active area.
18 . The continuous glucose monitoring system of claim 1 , wherein the waterproof housing withstands immersion in one meter of water for up to at least 30 minutes.
19 . The continuous glucose monitoring system of claim 1 , wherein the first portion of the sensor is disposed within the waterproof housing.
20 . The continuous glucose monitoring system of claim 1 , wherein the receiving unit further comprises:
a battery; and
a display configured to provide a battery level indicator display.
21 . The continuous glucose monitoring system of claim 1 , wherein the sensing region comprises a sensing element, the sensing element being in a well of a sensor substrate and/or the sensing element being on or adjacent to a modified area of the sensor substrate having a liquid mobility characteristic different than an adjacent area of the sensor substrate.
22 . A continuous glucose monitoring system, comprising:
an on-body unit including:
a waterproof housing encasing sensor electronics including
a non-transitory memory,
a battery, and
an on-body-unit antenna, and
a transcutaneous sensor having a first portion disposed within the waterproof housing and electrically coupled to the sensor electronics, and a second portion positionable beneath a skin surface of a user in a subcutaneous space and configured to generate a signal associated with a glucose level, wherein the second portion includes:
a working electrode,
a sensing region, including glucose oxidase, disposed over the working electrode, and
a glucose flux modulating layer disposed over the working electrode, and
an identifier physically associated with the transcutaneous sensor to uniquely identify the transcutaneous sensor during manufacturing; and
a receiver unit including a receiver antenna configured to communicate with the on-body-unit antenna via a communication link;
wherein individualized calibration information is stored in the non-transitory memory, is specific to the transcutaneous sensor, and is determined based at least in part on:
a sensitivity of a first subset of a plurality of transcutaneous sensors determined from data obtained by in vitro testing the first subset;
a measured individualized parameter of each transcutaneous sensor in a second subset of the plurality of transcutaneous sensors, wherein the second subset includes the transcutaneous sensor; and
individualized calibration information for each transcutaneous sensor in the second subset determined prior to distribution and by having performed (a)-(b) independently for each transcutaneous sensor in the second subset:
(a) determining, prior to distribution, an in vivo sensitivity of a respective transcutaneous sensor in the second subset determined by correlating a representation of the individualized parameter for the respective transcutaneous sensor in the second subset and a representation of the sensitivity of the first subset utilizing a Bayesian regression model having a first input comprising the representation of the individualized parameter for the respective transcutaneous sensor in the second subset, a second input comprising the representation of the sensitivity of the first subset, and an output comprising an in vitro sensitivity of the respective transcutaneous sensor; and
(b) determining the individualized calibration information for the respective transcutaneous sensor determined based on in vivo sensitivity of the respective transcutaneous sensor.
23 . The continuous glucose monitoring system of claim 22 , wherein each of the transcutaneous sensors in the plurality comprises a sensing region and the individualized parameter is a size of the sensing region.
24 . The continuous glucose monitoring system of claim 23 , wherein the representation of the individualized parameter for the respective transcutaneous sensor in the second subset is a deviation of the size of the sensing region of the respective transcutaneous sensor from a central tendency of a size of the sensing region for the plurality of transcutaneous sensors.
25 . The continuous glucose monitoring system of claim 22 , wherein each of the transcutaneous sensors in the plurality comprises a membrane and wherein the individualized parameter is a size of the membrane.
26 . A continuous glucose monitoring system, comprising:
an on-body unit including:
a waterproof housing encasing sensor electronics including
a non-transitory memory,
a battery, and
an on-body-unit antenna, and
a transcutaneous sensor having a first portion disposed within the waterproof housing and electrically coupled to the sensor electronics, and a second portion positionable beneath a skin surface of a user in a subcutaneous space and configured to generate a signal associated with a glucose level, wherein the second portion includes:
a working electrode,
a sensing region, including glucose oxidase, disposed over the working electrode, and
a glucose flux modulating layer disposed over the working electrode, and
an identifier physically associated with the transcutaneous sensor to uniquely identify the transcutaneous sensor during manufacturing; and
a receiver unit including a receiver antenna configured to communicate with the on-body-unit antenna via a communication link;
wherein individualized calibrating information is stored in the non-transitory memory, is specific to the transcutaneous sensor, and is determined based at least in part on:
a sensitivity of a first subset of a plurality of transcutaneous sensors determined from data obtained by in vitro testing the first subset;
a measured individualized parameter of each transcutaneous sensor in a second subset of the plurality of transcutaneous sensors, wherein the second subset includes the transcutaneous sensor; and
individualized calibration information for each transcutaneous sensor in the second subset determined prior to distribution and by having performed (a)-(c) independently for each transcutaneous sensor in the second subset:
(a) determining, prior to distribution, an in vitro sensitivity of a respective transcutaneous sensor in the second subset by modeling a correlation between a representation of the individualized parameter for the respective transcutaneous sensor in the second subset and a representation of the in vitro sensitivity of the first subset utilizing a Bayesian regression model having a first input comprising the representation of the individualized parameter for the respective transcutaneous sensor in the second subset, a second input comprising the representation of the sensitivity of the first subset, and an output comprising the in vitro sensitivity of the respective transcutaneous sensor;
(b) determining an in vivo sensitivity of the respective transcutaneous sensor using a representation of the in vitro sensitivity of the respective transcutaneous sensor; and
(c) determining individualized calibration information for the respective transcutaneous sensor that corresponds to the in vivo sensitivity of the respective transcutaneous sensor.
27 . The continuous glucose monitoring system of claim 26 , wherein each of the transcutaneous sensors in the plurality comprises a sensing region and the individualized parameter is a size of the sensing region.
28 . The continuous glucose monitoring system of claim 27 , wherein the representation of the individualized parameter for the respective transcutaneous sensor in the second subset is a deviation of the size of the sensing region of the respective transcutaneous sensor from a central tendency of a size of the sensing region for the plurality of transcutaneous sensors.
29 . The continuous glucose monitoring system of claim 26 , wherein each of the transcutaneous sensors in the plurality comprises a membrane and wherein the individualized parameter is a size of the membrane.