U.S. patent application number 17/560852 was filed with the patent office on 2022-04-14 for systems, devices, and methods for authentication in an analyte monitoring environment.
The applicant listed for this patent is ABBOTT DIABETES CARE INC.. Invention is credited to Glenn Berman, Nathan Crouther, Michael R. Love, Gil Porat, Mark Sloan.
Application Number | 20220116395 17/560852 |
Document ID | / |
Family ID | |
Filed Date | 2022-04-14 |
View All Diagrams
United States Patent
Application |
20220116395 |
Kind Code |
A1 |
Love; Michael R. ; et
al. |
April 14, 2022 |
SYSTEMS, DEVICES, AND METHODS FOR AUTHENTICATION IN AN ANALYTE
MONITORING ENVIRONMENT
Abstract
Systems, devices, and methods are provided that allow the
authentication of devices within analyte monitoring systems. The
analyte monitoring systems can be in vivo systems and can include a
sensor control device with a sensor and accompanying circuitry, as
well as a reader device for communicating with the sensor control
device. The analyte monitoring systems can interface with a trusted
computer system located at a remote site. Numerous techniques of
authentication are disclosed that can enable the detection of
counterfeit components, such as a counterfeit sensor control
device.
Inventors: |
Love; Michael R.;
(Pleasanton, CA) ; Sloan; Mark; (Redwood City,
CA) ; Berman; Glenn; (Alameda, CA) ; Crouther;
Nathan; (San Francisco, CA) ; Porat; Gil;
(Mountain View, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ABBOTT DIABETES CARE INC. |
Alameda |
CA |
US |
|
|
Appl. No.: |
17/560852 |
Filed: |
December 23, 2021 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
17399559 |
Aug 11, 2021 |
|
|
|
17560852 |
|
|
|
|
16150769 |
Oct 3, 2018 |
11122043 |
|
|
17399559 |
|
|
|
|
15367922 |
Dec 2, 2016 |
10110603 |
|
|
16150769 |
|
|
|
|
14574017 |
Dec 17, 2014 |
9544313 |
|
|
15367922 |
|
|
|
|
61921372 |
Dec 27, 2013 |
|
|
|
International
Class: |
H04L 9/30 20060101
H04L009/30; A61B 5/00 20060101 A61B005/00; H04W 4/02 20180101
H04W004/02; H04W 12/06 20210101 H04W012/06; A61B 5/1486 20060101
A61B005/1486; A61B 5/145 20060101 A61B005/145; H04W 4/029 20180101
H04W004/029; H04W 4/80 20180101 H04W004/80; A61B 5/1495 20060101
A61B005/1495; G06F 7/58 20060101 G06F007/58 |
Claims
1-20. (canceled)
21. An in vivo analyte monitoring system, comprising a reader
device and sensor control device, wherein the sensor control device
comprises a sensor and analyte monitoring circuitry, and the sensor
is adapted to be inserted into the body of a user; wherein the
reader device is configured to: send an identification request to
the sensor control device via a local wireless communication path;
receive from the sensor control device, in response to the
identification request, an identifier and a token via the local
wireless communication path; authenticating the sensor control
device based on the identifier and token obtained from the sensor
control device; and if the sensor control device is authenticated,
reading sensed analyte data from the sensor control device.
22. The system of claim 21, wherein the reader device is configured
to communicate with the sensor control device over the local
wireless communication path using: a Near Field Communication, NFC,
protocol; a Radio Frequency Identification, RFID, protocol; a
Bluetooth protocol; or a Bluetooth Low Energy protocol.
23. The system of claim 21, wherein the reader device is a smart
phone, a tablet, a smart glass, or a smart glasses.
24. The system of claim 21, wherein the reader device is further
configured to, if the reader device determines that the sensor
control device is authentic and if the sensor has been inserted
into the body of the user, then to read information indicative of
an analyte level of the user from the sensor control device and
display the analyte level on a display of the reader device; and
optionally if the reader device determines that the sensor control
device is not authentic, terminate operation of the reader device
with the sensor control device.
25. The system of claim 21, wherein the reader device is configured
to use a remote trusted computer system to verify authenticity of
token and identifier.
26. The system of claim 21, wherein the reader device is configured
to store tokens and identifiers on a local registration database
and to perform verification of the authenticity of the token and
the identifier.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Non-Provisional
application Ser. No. 17/399,559, filed Aug. 11, 2021, which is a
continuation of U.S. Non-Provisional application Ser. No.
16/150,769, filed Oct. 3, 2018, now U.S. Pat. No. 11,122,043, which
is a continuation of U.S. Non-Provisional application Ser. No.
15/367,922, filed Dec. 2, 2016, now U.S. Pat. No. 10,110,603, which
is a divisional of U.S. Non-Provisional application Ser. No.
14/574,017, filed Dec. 17, 2014, now U.S. Pat. No. 9,544,313, which
claims priority to U.S. Provisional Application No. 61/921,372,
filed Dec. 27, 2013, all of which are incorporated by reference
herein in their entireties for all purposes.
FIELD
[0002] The subject matter described herein relates to systems,
devices, and methods for authentication in an analyte monitoring
environment.
BACKGROUND
[0003] The detection and/or monitoring of analyte levels, such as
glucose, ketones, lactate, oxygen, hemoglobin A1C, or the like, can
be vitally important to the health of an individual having
diabetes. Diabetics generally monitor their glucose levels to
ensure that they are being maintained within a clinically safe
range, and may also use this information to determine if and/or
when insulin is needed to reduce glucose levels in their bodies or
when additional glucose is needed to raise the level of glucose in
their bodies.
[0004] Growing clinical data demonstrates a strong correlation
between the frequency of glucose monitoring and glycemic control.
Despite such correlation, many individuals diagnosed with a
diabetic condition do not monitor their glucose levels as
frequently as they should due to a combination of factors including
convenience, testing discretion, pain associated with glucose
testing, and cost. For these and other reasons, needs exist for
improved analyte monitoring systems, devices, and methods.
SUMMARY
[0005] A number of systems have been developed for the automatic
monitoring of the analyte(s), like glucose, in bodily fluid such as
in the blood stream, in interstitial fluid ("ISF"), dermal fluid,
or in other biological fluid. Some of these systems are configured
so that at least a portion of a sensor control device is positioned
below a skin surface of a user, e.g., in a blood vessel or in the
subcutaneous tissue of a user, so that the monitoring is
accomplished in vivo. As such, these systems can be referred to as
"in vivo" monitoring systems. In vivo analyte monitoring systems
include "Continuous Analyte Monitoring" systems (or "Continuous
Glucose Monitoring" systems) that can broadcast data from a sensor
control device to a reader device continuously without prompting,
e.g., automatically according to a broadcast schedule. In vivo
analyte monitoring systems also include "Flash Analyte Monitoring"
systems (or "Flash Glucose Monitoring" systems or simply "Flash"
systems) that can transfer data from a sensor control device in
response to a scan or request for data by a reader device, such as
with a Near Field Communication (NFC) or Radio Frequency
Identification (RFID) protocol. In vivo analyte monitoring systems
can also operate without the need for finger stick calibration.
[0006] The in vivo analyte monitoring systems can be differentiated
from "in vitro" systems that contact a biological sample outside of
the body (or rather "ex vivo") and that typically include a meter
device that has a port for receiving an analyte test strip carrying
bodily fluid of the user, which can be analyzed to determine the
user's blood sugar level.
[0007] In vivo monitoring systems can include a sensor that, while
positioned in vivo, makes contact with the bodily fluid of the user
and senses the analyte levels contained therein. The sensor can be
part of the sensor control device that resides on the body of the
user and contains the electronics and power supply that enable and
control the analyte sensing. The sensor control device, and
variations thereof, can also be referred to as a "sensor control
unit," an "on-body electronics" device or unit, an "on-body" device
or unit, or a "sensor data communication" device or unit, to name a
few.
[0008] In vivo monitoring systems can also include a device that
receives sensed analyte data from the sensor control device and
processes and/or displays that sensed analyte data, in any number
of forms, to the user. This device, and variations thereof, can be
referred to as a "reader device" (or simply a "reader"), "handheld
electronics" (or a handheld), a "portable data processing" device
or unit, a "data receiver," a "receiver" device or unit (or simply
a receiver), or a "remote" device or unit, to name a few. Other
devices such as personal computers have also been utilized with or
incorporated into in vivo and in vitro monitoring systems.
[0009] An in vivo system manufacturer can provide users with both
the sensor control device and the corresponding reader device; in
some cases the two can be sold as a set. The sensor control device
can have a limited lifespan and can be replaced periodically (e.g.,
every two weeks), but the reader device can be used for a
significantly longer period of time and is reusable with each new
replacement sensor control device. In those cases the manufacturer
typically sells sensor control devices individually to the
user.
[0010] For competitive, quality, and other reasons, manufacturers
generally want users to operate only those sensor control devices
made or supplied by that manufacturer, with reader devices also
made or supplied by that manufacturer (or reader devices using
software supplied by that manufacturer). Similarly, manufacturers
may want to restrict the use of certain models of sensor control
devices with certain readers, and may want to restrict the use of
sensor control devices and/or readers to only certain geographic
regions. Therefore, a need exists to ensure that sensor control
devices supplied by a manufacturer are used only with those reader
devices either supplied by that manufacturer or operating with
software supplied by that manufacturer, and vice versa.
[0011] Furthermore, in recent years the threat of counterfeiting
has become a greater concern. Manufacturers have a need to guard
against the possibility of a third party selling "look-alike"
sensor control devices that are designed for use with the
manufacturer's reader device, or a device operating with software
provided by the manufacturer, but are not in fact designed and
built by the manufacturer.
[0012] A number of embodiments of systems, devices, and methods are
provided that allow for the authentication of components within an
in vivo or in vitro analyte monitoring environment. These
embodiments can allow for the detection of unauthorized devices, or
devices supplied by other manufacturers, as well as to restrict the
types of devices, regardless of manufacturer, that are used within
the environment. It should be noted that all embodiments described
herein are for example only and are not intended to further limit
the scope of the subject matter claimed herein beyond the explicit
language of the claims themselves.
[0013] Although the analyte monitoring systems, devices, and
methods can be for in vivo use, in vitro use, or both, the majority
of the example embodiments will be described as operating within an
in vivo analyte monitoring system.
[0014] For example, embodiments of methods of authentication in an
in vivo analyte monitoring system can include receiving, by a
reader device, an identifier from a sensor control device over a
local wireless communication path, where the sensor control device
includes a sensor and analyte monitoring circuitry, and the sensor
is adapted to be inserted into a body of a user, sending the
identifier from the reader device over an internet to a trusted
computer system having a stored registration database, and
receiving, by the reader device, an authentication result from the
trusted computer system over the internet, where the authentication
result indicates whether the sensor control device is or is not
authorized to operate with the reader device.
[0015] In many embodiments described herein, the identifier can be
a serial number of the sensor control device, a random number, one
or more calibration parameters for the sensor control device, other
values, and any combinations thereof.
[0016] In these and other embodiments, the methods can further
include sending an identification request from the reader device
over the local wireless communication path to the sensor control
device, where the sensor control device sends the identifier to the
reader device in response to receipt of the identification request.
The methods can also include determining, by the trusted computer
system, authenticity of the identifier by reference to a stored
registration database. If the identifier is in the stored
registration database, the methods can include determining if the
identifier is associated with an unused device.
[0017] In some embodiments, the registration database can include
one or more compilations of used and unused identifiers, and the
methods can include updating the registration database by
associating the identifier with a used device. In some embodiments,
the authentication result authorizes the reader device to operate
with the sensor control device if the identifier is associated with
an unused device, and the authentication result does not authorize
the reader device to operate (or prevents it from operating) with
the sensor control device if the identifier is associated with a
device that has already been used or is counterfeit.
[0018] A number of communication protocols can be used with the
embodiments described herein. For example, the reader device can
communicate with the sensor control device over a local wired or
wireless communication link. Wireless protocols that can be used
include Wi-Fi, near field communication (NFC), radio frequency
identification (RFID), Bluetooth, or Bluetooth Low Energy, to name
a few.
[0019] A number of types of reader devices can be used with the
embodiments described herein. For example, the reader device can be
a smart phone, a tablet, a wearable electronic assembly such as a
smart watch or smart glasses, or the like. The reader device can
include location determining hardware capable of determining a
current location of the reader device, such as global positioning
system (GPS) hardware.
[0020] In embodiments having location determining hardware, the
methods can include sending the current location of the reader
device over the internet to a trusted computer system, which can
generate an authentication result that either authorizes or does
not authorize the reader device to operate with the sensor control
device based on the current location. In some embodiments the
methods can include, if the identifier is not authorized for use in
the current location, displaying a message on a display of the
reader device indicating that the sensor control device is not
authorized for use in the current location.
[0021] The methods can further include reading, with the reader
device if an authentication result permits operation of the reader
device with the sensor control device and if the sensor has been
inserted into the body of the user, information indicative of an
analyte level of the user from the sensor control device and
displaying the analyte level on a display of the reader device.
[0022] Other example embodiments are also described of in vivo
analyte monitoring systems having a reader device. The reader
device can include a first receiver capable of receiving an
identifier and sensed analyte data from an in vivo sensor control
device over the local wireless communication path, communication
circuitry capable of transmitting the identifier over the internet
to a trusted computer system, a second receiver capable of
receiving an authentication result over the internet from the
trusted computer system, and a processor programmed to read the
authentication result and, if the authentication result indicates
that the sensor control device is authentic, cause the sensed
analyte data to be displayed to the user. If the authentication
result indicates that the sensor control device is not authentic,
then the processor can be programmed to cease operation of the
reader device with the sensor control device. In some embodiments,
the processor is further programmed to generate an identification
request for transmittal by the reader device over the local
wireless communication path to the sensor control device.
[0023] The system can further include the sensor control device
that, in some embodiments, can include a sensor adapted to be
inserted into a body of a user, analyte monitoring circuitry
coupled with the sensor, a memory capable of storing an identifier,
and communication circuitry capable of communicating the identifier
and sensed analyte data over a local wireless communication path to
the reader device.
[0024] The system can further include a trusted computer system
that, in some embodiments, can include a registration database
and/or a server. The trusted computer system can be programmed to
verify whether the identifier received from the reader device is or
is not associated with an authentic sensor control device. In some
embodiments, the registration database can include a plurality of
identifiers and, for each identifier within the plurality of
identifiers, an indication whether the identifier is authentic. The
registration database can also include one or more compilations of
used and unused identifiers.
[0025] Also disclosed are example embodiments of methods of
authentication within in vivo analyte monitoring systems that can
include receiving, by a reader device, an identifier from a sensor
control device over a local wireless communication path, where the
sensor control device includes a sensor and analyte monitoring
circuitry and the sensor is adapted to be inserted into the body of
a user, and where the reader device includes memory having a
registration database stored thereon. The methods can further
include determining authenticity of the identifier by reference to
the registration database, for example, by determining whether the
identifier is in the stored registration database and, if so,
whether the identifier is associated with an unused device.
[0026] In some embodiments, the reader device commences or
continues normal operation with the sensor control device if the
identifier is associated with an unused device, e.g., by receiving
sensed analyte data from the sensor control device and/or
displaying sensed analyte data from the sensor control device. If
the identifier is associated with a device that has already been
used or is counterfeit, then the reader device, in certain
embodiments, does not operate with the sensor control device or
terminates communications with the sensor control device.
[0027] Still other example embodiments are described of methods of
authenticating in vivo analyte monitoring systems having a sensor
control device and a reader device. In these other embodiments, the
methods can include receiving, by a reader device, an identifier
from a sensor control device over a local wireless communication
path, where the sensor control device includes a sensor and analyte
monitoring circuitry, and where the sensor is adapted to be
inserted into a body of a user. The methods can also include
receiving, by the reader device, a first token, then determining,
by the reader device, if the identifier is associated with an
unused sensor control device by reference to a registration
database, and, if the identifier is associated with an unused
sensor control device, then comparing, by the reader device, the
first token with a second token stored in the registration database
to determine if the first and second tokens match.
[0028] In certain embodiments, if the identifier is not associated
with an unused sensor control device, then operation with the
sensor control device is ceased, and the user can be notified of
the same. The reader device can operate with the sensor control
device if the identifier is associated with an unused device and
the first and second token match.
[0029] If the first and second tokens match, then some embodiments
of the methods can include reading, with the reader device,
information indicative of an analyte level of the user from the
sensor control device and then displaying the analyte level on a
display of the reader device.
[0030] Additional example embodiments are described of methods of
authenticating an in vivo analyte monitoring system having a sensor
control device and a reader device. In these other embodiments, the
methods can include receiving, by a reader device, an identifier
from the sensor control device over a local wireless communication
path, where the sensor control device includes a sensor and analyte
monitoring circuitry, and where the sensor is adapted to be
inserted into a body of a user. These embodiments can also include
receiving a token at the reader device, where the token is known to
be associated with the sensor control device, sending the
identifier and the token from the reader device over an internet to
a trusted computer system having a registration database, and
receiving an authentication result from the trusted computer system
over the internet by the reader device, where the authentication
result indicates whether the sensor control device is or is not
authorized to operate with the reader device.
[0031] In certain embodiments, receiving the token, at the reader
device, includes receiving the token from the sensor control device
over the local wireless communication path, or using an optical
scanner on the reader device to scan a barcode (e.g., 2D or 3D) on
a package for the sensor control device, where the barcode is
representative of the token, or using a near field communication
(NFC) device to scan a package for the sensor control device, where
the package includes an element adapted to provide information
representative of the token in response to an NFC scan. The element
can be, for example, an NFC tag. In other embodiments, the token
can be printed on a package for the sensor control device and the
methods can include reading, by a human, the token from the
package, and manually inputting the token into the reader
device.
[0032] In certain embodiments, the methods can include determining,
by the trusted computer system, authenticity of the identifier and
the token by reference to the registration database. For example,
if the identifier is present in the registration database and
associated with an unused device, then it can be determined if the
token received by the trusted computer system matches the token
stored within the registration database. If the tokens match, then
the sensor control device can be authenticated.
[0033] In some embodiments, a plurality of tokens and identifiers
are stored in the registration database and only one token is
associated with the identifier. If the identifier is associated
with an unused device, then certain embodiments of the methods can
include updating the registration database by associating the
identifier with a used device.
[0034] In these and other embodiments, if the authentication result
permits operation of the reader device with the sensor control
device and if the sensor has been inserted into the body of the
user, then the methods can include reading, with the reader device,
information indicative of an analyte level of the user from the
sensor control device, and displaying the analyte level on a
display of the reader device.
[0035] Other example embodiments of systems, devices, and methods
of authentication that use public and private keys are disclosed.
For example, certain embodiments of these methods of authentication
within in vivo analyte monitoring systems can include providing a
private key to a reader device, where the private key is supplied
by a sensor control device or a package for the sensor control
device, and where the sensor control device includes a sensor and
analyte monitoring circuitry and the sensor is adapted to be
inserted into the body of a user, authenticating the private key
using a public key stored within the reader device, and if the
private key is authenticated, reading sensed analyte data from the
sensor control device by the reader device.
[0036] In certain embodiments, providing the private key to the
reader device includes receiving, by the reader device, the private
key from the sensor control device over the local wireless
communication path, scanning a barcode (e.g., 2D or 3D) on a
package for the sensor control device with an optical scanner of
the reader device, where the barcode is representative of the
private key, or scanning a package for the sensor control device
with a near field communication (NFC) device, where the package
includes an element, e.g., an NFC tag, adapted to provide
information representative of the private key in response to the
NFC scan. In other embodiments, the private key is printed on the
package for the sensor control device and the methods can include
reading, by a human, the private key from the package and manually
inputting the private key into the reader device.
[0037] In still other embodiments, methods of authentication within
in vivo analyte monitoring systems can include digitally signing
data with a private key, where the private key has a corresponding
public key, storing the digitally signed data in the memory of a
sensor control device, where the sensor control device includes a
sensor and analyte monitoring circuitry and the sensor is
configured to be inserted into the body of a user, and storing the
corresponding public key in the memory of a reader device, where
the reader device is capable of receiving the digitally signed data
from the sensor control device and is programmed to verify that the
digitally signed data is authentic using the public key.
[0038] In certain embodiments, the methods can also include
determining at least one calibration parameter for the sensor,
where the data that is digitally signed with the private key is the
at least one calibration parameter, and where the at least one
calibration parameter is determined separately for each one of a
plurality of sensor control devices. Embodiments of the methods can
also include storing the at least one calibration parameter, in
addition to the digitally signed data, in the memory of the sensor
control device. In some embodiments, the reader device is capable
of receiving the at least one calibration parameter from the sensor
control device and is programmed to compare the received at least
one calibration parameter with the at least one calibration
parameter that was digitally signed. The reader device can be
programmed to operate normally with the sensor control device if
the received at least one calibration parameter matches the at
least one calibration parameter that was digitally signed, and can
be programmed to cease operation with the sensor control device if
the received at least one calibration parameter does not match the
at least one calibration parameter that was digitally signed.
[0039] In all embodiments described herein that operate with a
digital signature or digitally signed data, that digital signature
or digitally signed data can be further encrypted prior to transfer
between devices and use in a verification process.
[0040] In certain embodiments, the methods can include receiving an
identifier from the reader device, the identifier having been sent
to the reader device by the sensor control device, determining, by
reference to the registration database, whether the identifier is
or is not authentic, and sending an authentication result to the
reader device, where the authentication result indicates whether
the identifier is or is not authentic. The identifier can be
determined to be authentic if it is not associated with a used
sensor control device or a counterfeit sensor control device in the
registration database. Certain embodiments of the methods can
further include updating, if the identifier is determined to be
authentic, the registration database to reflect that the identifier
is now associated with a used sensor control device and/or
downloading at least a portion of the registration database to the
reader device.
[0041] In other embodiments, methods of authentication within in
vivo analyte monitoring systems can include: receiving, by a reader
device, digitally signed data from a sensor control device, where
the sensor control device includes a sensor and analyte monitoring
circuitry and the sensor is configured to be inserted into the body
of a user; using, by the reader device, a public key to verify
whether the digitally signed data is authentic; and determining, by
the reader device, whether an identifier received from the sensor
control device is or is not associated with a sensor control device
that has been used, by reference to a local database stored in a
memory of the reader device. In certain embodiments, the identifier
is at least part of the digitally signed data and is received from
the sensor control device as the digitally signed data.
[0042] For each and every embodiment of a method disclosed herein,
systems and devices capable of performing each of those embodiments
are covered within the scope of the present disclosure. For
example, embodiments of sensor control devices are disclosed and
these devices can have one or more sensors, analyte monitoring
circuits (e.g., an analog circuit), memories, power sources,
communication circuits, transmitters, receivers, processors and/or
controllers that can be programmed to execute any and all method
steps or facilitate the execution of any and all method steps.
These sensor control device embodiments can be used and can be
capable of use to implement those steps performed by a sensor
control device from any and all of the methods described herein.
Likewise, embodiments of reader devices are disclosed having one or
more transmitters, receivers, memories, power sources, processors
and/or controllers that can be programmed to execute any and all
method steps or facilitate the execution of any and all method
steps. These embodiments of the reader devices can be used to
implement those steps performed by a reader device from any and all
of the methods described herein. Embodiments of trusted computer
systems are also disclosed. These trusted computer systems can
include one or more processors, controllers, transmitters,
receivers, memories, databases, servers, and/or networks, and can
be discretely located or distributed across multiple geographic
locales. These embodiments of the trusted computer systems can be
used to implement those steps performed by a trusted computer
system from any and all of the methods described herein.
[0043] Other systems, devices, methods, features and advantages of
the subject matter described herein will be or will become apparent
to one with skill in the art upon examination of the following
figures and detailed description. It is intended that all such
additional systems, devices, methods, features and advantages be
included within this description, be within the scope of the
subject matter described herein, and be protected by the
accompanying claims. In no way should the features of the example
embodiments be construed as limiting the appended claims, absent
express recitation of those features in the claims.
BRIEF DESCRIPTION OF THE FIGURES
[0044] The details of the subject matter set forth herein, both as
to its structure and operation, may be apparent by study of the
accompanying figures, in which like reference numerals refer to
like parts. The components in the figures are not necessarily to
scale, emphasis instead being placed upon illustrating the
principles of the subject matter. Moreover, all illustrations are
intended to convey concepts, where relative sizes, shapes and other
detailed attributes may be illustrated schematically rather than
literally or precisely.
[0045] FIG. 1 is a high level diagram depicting an example
embodiment of an analyte monitoring system for real time analyte
(e.g., glucose) measurement, data acquisition and/or
processing.
[0046] FIG. 2A is a block diagram depicting an example embodiment
of a reader device.
[0047] FIGS. 2B-C are block diagrams depicting example embodiments
of a sensor control device.
[0048] FIG. 3A is an illustration depicting an example embodiment
of an in vivo monitoring system having authentication
capability.
[0049] FIGS. 3B-C depict examples of data compilations, in human
readable form, that could otherwise be stored, in machine-readable
form, within an example embodiment of a database.
[0050] FIG. 3D is an illustration depicting another example
embodiment of an in vivo monitoring system having authentication
capability.
[0051] FIGS. 4-7 are illustrations depicting additional example
embodiments of in vivo monitoring systems having various
authentication capabilities.
[0052] FIGS. 8A-C are flow diagrams depicting example embodiments
of a method of operating an in vivo monitoring system having
authentication capability.
DETAILED DESCRIPTION
[0053] Before the present subject matter is described in detail, it
is to be understood that this disclosure is not limited to the
particular embodiments described, as such may, of course, vary. It
is also to be understood that the terminology used herein is for
the purpose of describing particular embodiments only, and is not
intended to be limiting, since the scope of the present disclosure
will be limited only by the appended claims.
[0054] As used herein and in the appended claims, the singular
forms "a", "an", and "the" include plural referents unless the
context clearly dictates otherwise.
[0055] The publications discussed herein are provided solely for
their disclosure prior to the filing date of the present
application. Nothing herein is to be construed as an admission that
the present disclosure is not entitled to antedate such publication
by virtue of prior disclosure. Further, the dates of publication
provided may be different from the actual publication dates which
may need to be independently confirmed.
[0056] It should be noted that all features, elements, components,
functions, and steps described with respect to any embodiment
provided herein are intended to be freely combinable and
substitutable with those from any other embodiment. If a certain
feature, element, component, function, or step is described with
respect to only one embodiment, then it should be understood that
that feature, element, component, function, or step can be used
with every other embodiment described herein unless explicitly
stated otherwise. This paragraph therefore serves as antecedent
basis and written support for the introduction of claims, at any
time, that combine features, elements, components, functions, and
steps from different embodiments, or that substitute features,
elements, components, functions, and steps from one embodiment with
those of another, even if the following description does not
explicitly state, in a particular instance, that such combinations
or substitutions are possible. It is explicitly acknowledged that
express recitation of every possible combination and substitution
is overly burdensome, especially given that the permissibility of
each and every such combination and substitution will be readily
recognized by those of ordinary skill in the art.
[0057] Generally, embodiments of the present disclosure are used
with in vivo systems, devices, and methods for detecting at least
one analyte, such as glucose, in body fluid, (e.g., subcutaneously
within the ISF or blood, or within the dermal fluid of the dermal
layer). Accordingly, many embodiments include in vivo analyte
sensors arranged so that at least a portion of the sensor is
positioned in the body of a user to obtain information about at
least one analyte of the body. It should be noted, however, that
the embodiments disclosed herein can be used with in vivo analyte
monitoring systems that incorporate in vitro capability, as well
has purely in vitro or ex vivo analyte monitoring systems.
[0058] As mentioned, a number of embodiments of systems, devices,
and methods are provided that allow for the authentication of
components within an in vivo, in vitro, or ex vivo analyte
monitoring environment. These embodiments can allow for the
detection of unauthorized devices, or devices supplied by other
manufacturers, as well as to restrict the types of devices,
regardless of manufacturer, that are used within the environment.
Before describing these aspects of the embodiments in detail,
however, it is first desirable to describe examples of devices that
can be present within, for example, an in vivo analyte monitoring
system, as well as examples of their operation.
Example Embodiments of In Vivo Analyte Monitoring Systems
[0059] FIG. 1 is an illustrative view depicting an example of an in
vivo analyte monitoring system 100 having a sensor control device
102 and a reader device 120 that communicate with each other over a
local communication path (or link) 140, which can be wired or
wireless, and uni-directional or bi-directional. In embodiments
where path 140 is wireless, a near field communication (NFC)
protocol, RFID protocol, Bluetooth or Bluetooth Low Energy
protocol, Wi-Fi protocol, proprietary protocol, or the like can be
used, including those communication protocols in existence as of
the date of this filing or their later developed variants.
[0060] Reader device 120 is also capable of wired, wireless, or
combined communication with a remote computer system 170 over
communication path (or link) 141 and with trusted computer system
180 over communication path (or link) 142. Communication paths 141
and 142 can be part of a telecommunications network, such as a
Wi-Fi network, a local area network (LAN), a wide area network
(WAN), the internet, or other data network for uni-directional or
bi-directional communication. In an alternative embodiment,
communication paths 141 and 142 can be the same path. All
communications over paths 140, 141, and 142 can be encrypted and
sensor control device 102, reader device 120, remote computer
system 170, and trusted computer system 180 can each be configured
to encrypt and decrypt those communications sent and received.
[0061] Sensor control device 102 can include a housing 103
containing in vivo analyte monitoring circuitry and a power source.
The in vivo analyte monitoring circuitry is electrically coupled
with an analyte sensor 104 that extends through an adhesive patch
105 and projects away from housing 103. Adhesive patch 105 contains
an adhesive layer (not shown) for attachment to a skin surface of
the body of the user. (Other forms of body attachment to the body
may be used, in addition to or instead of adhesive.)
[0062] Sensor 104 is adapted to be at least partially inserted into
the body of the user, where it can make fluid contact with that
user's body fluid (e.g., interstitial fluid (ISF), dermal fluid, or
blood) and be used, along with the in vivo analyte monitoring
circuitry, to measure analyte-related data of the user. Sensor 104
and any accompanying sensor control electronics can be applied to
the body in any desired manner. For example, also shown in FIG. 1
is an embodiment of insertion device 150 that, when operated,
transcutaneously (or subcutaneously) positions a portion of analyte
sensor 104 through the user's skin and into contact with the bodily
fluid, and positions sensor control device 102 with adhesive patch
105 onto the skin. In other embodiments, insertion device 150 can
position sensor 104 first, and then accompanying sensor control
electronics can be coupled with sensor 104 afterwards, either
manually or with the aid of a mechanical device. Other devices,
systems, and methods that may be used with embodiments herein,
including variations of sensor control device 102, are described,
e.g., in U.S. Publication Nos. 2010/0324392, 2011/0106126,
2011/0190603, 2011/0191044, 2011/0082484, 2011/0319729, and
2012/0197222, the disclosures of each of which are incorporated
herein by reference for all purposes.
[0063] After collecting the analyte-related data, sensor control
device 102 can then wirelessly communicate that data (such as, for
example, data corresponding to monitored analyte level and/or
monitored temperature data, and/or stored historical analyte
related data) to a reader device 120 where, in certain embodiments,
it can be algorithmically processed into data representative of the
analyte level of the user and then displayed to the user and/or
otherwise incorporated into a diabetes monitoring regime.
[0064] As shown in FIG. 1, reader device 120 includes a display 122
to output information to the user and/or to accept an input from
the user (e.g., if configured as a touch screen), and one optional
input component 121 (or more), such as a button, actuator, touch
sensitive switch, capacitive switch, pressure sensitive switch, jog
wheel or the like, to input data or commands to reader device 120
or otherwise control the operation of reader device 120.
[0065] In certain embodiments, input component 121 of reader device
120 may include a microphone and reader device 120 may include
software configured to analyze audio input received from the
microphone, such that functions and operation of the reader device
120 may be controlled by voice commands. In certain embodiments, an
output component of reader device 120 includes a speaker (not
shown) for outputting information as audible signals. Similar voice
responsive components such as a speaker, microphone and software
routines to generate, process and store voice driven signals may be
provided to sensor control device 102.
[0066] In certain embodiments, display 122 and input component 121
may be integrated into a single component, for example a display
that can detect the presence and location of a physical contact
touch upon the display such as a touch screen user interface. In
such embodiments, the user may control the operation of reader
device 120 by utilizing a set of pre-programmed motion commands,
including, but not limited to, single or double tapping the
display, dragging a finger or instrument across the display,
motioning multiple fingers or instruments toward one another,
motioning multiple fingers or instruments away from one another,
etc. In certain embodiments, a display includes a touch screen
having areas of pixels with single or dual function capacitive
elements that serve as LCD elements and touch sensors.
[0067] Reader device 120 also includes one or more data
communication ports 123 for wired data communication with external
devices such as a remote terminal, e.g., a personal computer.
Example data communication ports include USB ports, mini USB ports,
RS-232 ports, Ethernet ports, Firewire ports, or other similar data
communication ports configured to connect to the compatible data
cables. Reader device 120 may also include an integrated or
attachable in vitro glucose meter, including an in vitro test strip
port (not shown) to receive an in vitro glucose test strip for
performing in vitro blood glucose measurements.
[0068] Referring still to FIG. 1, display 122 can be configured to
display a variety of information--some or all of which may be
displayed at the same or different time on display 122. The
displayed information can be user-selectable so that a user can
customize the information shown on a given display screen. Display
122 may include, but is not limited to, graphical display 138, for
example, providing a graphical output of glucose values over a
monitored time period (which may show: markers such as meals,
exercise, sleep, heart rate, blood pressure, etc.; numerical
display 132, for example, providing monitored glucose values
(acquired or received in response to the request for the
information); and trend or directional arrow display 131 that
indicates a rate of analyte change and/or a rate of the rate of
analyte change, e.g., by moving locations on display 122).
[0069] As further shown in FIG. 1, display 122 may also include:
date display 135, which can provide date information for the user;
time of day information display 139 providing time of day
information to the user; battery level indicator display 133
graphically showing the condition of the battery (rechargeable or
disposable) of reader device 120; sensor calibration status icon
display 134, for example, in monitoring systems that require
periodic, routine or a predetermined number of user calibration
events notifying the user that the analyte sensor calibration is
necessary; audio/vibratory settings icon display 136 for displaying
the status of the audio/vibratory output or alarm state; and
wireless connectivity status icon display 137 that provides
indication of wireless communication connection with other devices
such as sensor control device 102, remote computer system 170,
and/or trusted computer system 180. Display 122 may further include
simulated touch screen buttons 125, 126 for accessing menus,
changing display graph output configurations or otherwise
controlling the operation of reader device 120.
[0070] In certain embodiments, reader device 120 can be configured
to output alarms, alert notifications, glucose values, etc., which
may be visual, audible, tactile, or any combination thereof. Reader
device 120 may include other output components such as a speaker,
vibratory output component and the like to provide audible and/or
vibratory output indications to the user in addition to the visual
output indication provided on display 122. Further details and
other display embodiments can be found in, e.g., U.S. Publication
No. 2011/0193704, which is incorporated herein by reference for all
purposes.
[0071] Reader device 120 can be connected to a remote terminal 170,
such as a personal computer, which can be used by the user or a
medical professional to display and/or analyze the collected
analyte data. Reader device 120 can also be connected to a trusted
computer system 180 that can be used for authentication of a third
party software application. In both instances, reader device 120
can function as a data conduit to transfer the stored analyte level
information from the sensor control device 102 to remote terminal
170 or trusted computer system 180. In certain embodiments, the
received data from the sensor control device 102 may be stored
(permanently or temporarily) in one or more memories of reader
device 120.
[0072] Remote terminal 170 may be a personal computer, a server
terminal, a laptop computer, a tablet, or other suitable data
processing device. Remote terminal 170 can be (or include) software
for data management and analysis and communication with the
components in analyte monitoring system 100. Operation and use of
remote terminal 170 is further described in the '225 Publication
incorporated herein (below). Analyte monitoring system 100 can also
be configured to operate with a data processing module (not shown),
also as described in the incorporated '225 Publication.
[0073] Trusted computer system 180 can be within the possession of
the manufacturer or distributor of sensor control device 102,
either physically or virtually through a secured connection, and
can be used to perform authentication of sensor control device 102.
Authentication of sensor control device 102 can also be outsourced
to a third-party, such that the third-party is physically in
possession of trusted computer system 180. Trusted computer system
180 is trusted in the sense that system 100 can assume that it
provides valid information and determinations upon which a
foundation for the authentication activities can be based. Trusted
computer system 180 can be trusted simply by virtue of it being
within the possession or control of the manufacturer, e.g., like a
typical web server. Alternatively, trusted computer system 180 can
be implemented in a more secure fashion such as by requiring
additional password, encryption, firewall, or other internet access
security enhancements that further guard against counterfeiter
attacks or attacks by computer hackers.
[0074] Trusted computer system 180 can also be referred to as
registration computer system 180, or simply computer system 180.
Trusted computer system 180 can include one or more computers,
servers, networks, databases, and the like.
[0075] In some embodiments, trusted computer system 180 includes a
registration database 181, or has secure access to a registration
database, which contains comprehensive registration information for
all manufactured sensor control devices 102. Upon the completion of
the manufacturing process, authentication information about a
particular sensor control device 102 can be stored within that
sensor control device 102, placed on the packaging of that sensor
control device 102, or otherwise associated with that sensor
control device 102. This authentication information can also be
stored within registration database 181 of trusted computer system
180 for future reference during a subsequent authentication process
for that sensor control device 102.
[0076] The authentication information can be in the form of a
unique identifier, where trusted computer system 180 can associate
every unique identifier with a different sensor control device 102,
as well as an indication whether that sensor control device 102 has
not yet been used or has already been used. In these or other
embodiments, authentication information can be in the form of a
pair of keys, such as a private key and a public key, which are
disseminated within system 100. In some embodiments, the private
key is retained by trusted computer system 180 and the public key
is in the possession of reader device 120 (or sensor control device
102). The keys themselves can be used for authentication, or they
can be used to process digital signatures, e.g., digitally sign and
un-sign data, to verify the authenticity of reader device 120 (or
sensor control device 102).
[0077] The processing of data within system 100 can be performed by
one or more control logic units or processors of reader device 120,
remote terminal 170, trusted computer system 180, and/or sensor
control device 102. For example, raw data measured by sensor 104
can be algorithmically processed into a value that represents the
analyte level and that is readily suitable for display to the user,
and this can occur in sensor control device 102, reader device 120,
remote terminal 170, or trusted computer system 180. This and any
other information derived from the raw data can be displayed in any
of the manners described above (with respect to display 122) on any
display residing on any of sensor control device 102, reader device
120, remote terminal 170, or trusted computer system 180.
[0078] The information may be utilized by the user to determine any
necessary corrective actions to ensure the analyte level remains
within an acceptable and/or clinically safe range. Other visual
indicators, including colors, flashing, fading, etc., as well as
audio indicators, including a change in pitch, volume, or tone of
an audio output, and/or vibratory or other tactile indicators may
also be incorporated into the outputting of trend data as means of
notifying the user of the current level, direction, and/or rate of
change of the monitored analyte level. For example, based on a
determined rate of glucose change, programmed clinically
significant glucose threshold levels (e.g., hyperglycemic and/or
hypoglycemic levels), and current analyte level derived by an in
vivo analyte sensor, an algorithm stored on a computer readable
medium of system 100 can be used to determine the time it will take
to reach a clinically significant level and can be used to output a
notification in advance of reaching the clinically significant
level, e.g., 30 minutes before a clinically significant level is
anticipated, and/or 20 minutes, and/or 10 minutes, and/or 5
minutes, and/or 3 minutes, and/or 1 minute, and so on, with outputs
increasing in intensity or the like.
[0079] Referring now in further detail to reader device 120, that
device 120 can be a mobile communication device such as a mobile
telephone including, but not limited to, a Wi-Fi or internet
enabled smart phone, tablet, or personal digital assistant (PDA).
Examples of smart phones can include those mobile phones based on a
Windows.RTM. operating system, Android.TM. operating system,
iPhone.RTM. operating system, Palm.RTM. WebOS.TM., Blackberry.RTM.
operating system, or Symbian.RTM. operating system, with data
network connectivity functionality for data communication over an
internet connection and/or a local area network (LAN).
[0080] Reader device 120 can also be configured as a mobile smart
wearable electronics assembly, such as an optical assembly that is
worn over or adjacent to the user's eye (e.g., a smart glass or
smart glasses, such as Google glasses, which is a mobile
communication device). This optical assembly can have a transparent
display that displays information about the user's analyte level
(as described herein) to the user while at the same time allowing
the user to see through the display such that the user's overall
vision is minimally obstructed. The optical assembly may be capable
of wireless communications similar to a smart phone. Other examples
of wearable electronics include devices that are worn around or in
the proximity of the user's wrist (e.g., a watch, etc.), neck
(e.g., a necklace, etc.), head (e.g., a headband, hat, etc.),
chest, or the like.
[0081] FIG. 2A is a block diagram of an example embodiment of a
reader device 120 configured as a smart phone. Here, reader device
120 includes an input component 121, display 122, and processing
hardware 226, which can include one or more processors,
microprocessors, controllers, and/or microcontrollers, each of
which can be a discrete chip or distributed amongst (and a portion
of) a number of different chips. Here, processing hardware 226
includes a communications processor 222 having on-board memory 223
and an applications processor 224 having on-board memory 225.
Reader device 120 further includes an RF transceiver 228 coupled
with an RF antenna 229, a memory 230, multi-functional circuitry
232 with one or more associated antennas 234, a power supply 236,
and power management circuitry 238. FIG. 2A is an abbreviated
representation of the typical hardware and functionality that
resides within a smart phone and those of ordinary skill in the art
will readily recognize that other hardware and functionality (e.g.,
codecs, drivers, glue logic, can also be included here.
[0082] Communications processor 222 can interface with RF
transceiver 228 and perform analog-to-digital conversions, encoding
and decoding, digital signal processing and other functions that
facilitate the conversion of voice, video, and data signals into a
format (e.g., in-phase and quadrature) suitable for provision to RF
transceiver 228, which can then transmit the signals wirelessly.
Communications processor 222 can also interface with RF transceiver
228 to perform the reverse functions necessary to receive a
wireless transmission and convert it into digital data, voice, and
video.
[0083] Applications processor 224 can be adapted to execute the
operating system and any software applications that reside on
reader device 120, process video and graphics, and perform those
other functions not related to the processing of communications
transmitted and received over RF antenna 229. The smart phone
operating system will operate in conjunction with a number of
applications on reader device 120. Any number of applications can
be running on reader device 120 at any one time, and will typically
include one or more applications that are related to a diabetes
monitoring regime, in addition to the other commonly used
applications that are unrelated to such a regime, e.g., email,
calendar, weather, sports, games, etc.
[0084] Memory 230 can be shared by one or more the various
functional units present within reader device 120, or can be
distributed amongst two or more of them (e.g., as separate memories
present within different chips). Memory 230 can also be a separate
chip of its own. Memory 230 is non-transitory, and can be volatile
(e.g., RAM, etc.) and/or non-volatile memory (e.g., ROM, flash
memory, F-RAM, etc.).
[0085] Multi-functional circuitry 232 can be implemented as one or
more chips and/or components (e.g., transmitter, receiver,
transceiver, and/or other communication circuitry) that perform
other functions such as local wireless communications (e.g., for
Wi-Fi, Bluetooth, Bluetooth Low Energy, Near Field Communication
(NFC), Radio Frequency Identification (RFID), and others) and
determining the geographic position of reader device 120 (e.g.,
global positioning system (GPS) hardware). One or more other
antennas 234 are associated with the functional circuitry 232 as
needed to operate with the various protocols and circuits.
[0086] Power supply 236 can include one or more batteries, which
can be rechargeable or single-use disposable batteries. Power
management circuitry 238 can regulate battery charging and power
supply monitoring, boost power, perform DC conversions, and the
like.
[0087] As mentioned, the reader device 120 may also include one or
more data communication ports such as USB port (or connector) or
RS-232 port (or any other wired communication ports) for data
communication with a remote terminal 170, trusted computer system
180, or sensor control device 102, to name a few.
[0088] Reader device 120 may include a strip port (not shown) or be
coupled with a strip port module (not shown) configured to receive
in vitro test strips. In such a configuration, reader device 120
can process a fluid sample on a test strip, determine an analyte
level contained therein, and display that result to a user. Any
suitable in vitro test strip may be employed, e.g., test strips
that only require a very small amount (e.g., one microliter or
less, e.g., about 0.5 microliter or less, e.g., about 0.1
microliter or less), of applied sample to the strip in order to
obtain accurate glucose information, e.g. FreeStyle.RTM. or
Precision.RTM. blood glucose test strips and systems from Abbott
Diabetes Care Inc. Reader devices with in vitro monitors and test
strip ports may be configured to conduct in vitro analyte
monitoring with no user calibration in vitro test strips (i.e., no
human intervention calibration), such as FreeStyle Lite glucose
test strips from Abbott Diabetes Care Inc. Detailed description of
such test strips and devices for conducting in vitro analyte
monitoring is provided in U.S. Pat. Nos. 6,377,894, 6,616,819,
7,749,740, 7,418,285; U.S. Published Patent Publication Nos.
2004/0118704, 2006/0091006, 2008/0066305, 2008/0267823,
2010/0094110, 2010/0094111, and 2010/0094112, and 2011/0184264, the
disclosure of each of which are incorporated herein by reference
for all purposes. The present inventive subject matter can be used
with and/or in the systems, devices, and methods described in these
incorporated references.
[0089] FIGS. 2B-C are block schematic diagrams depicting example
embodiments of sensor control device 102 having analyte sensor 104
and sensor electronics 110 (including analyte monitoring circuitry)
that can have the majority of the processing capability for
rendering end-result data suitable for display to the user. In FIG.
2B, a single semiconductor chip 201 is depicted that can be a
custom application specific integrated circuit (ASIC). Shown within
ASIC 201 are certain high-level functional units, including an
analog front end (AFE) 202, power management (or control) circuitry
204, processor 206, and communication circuitry 208 (which can be
implemented as a transmitter, receiver, transceiver, passive
circuit, or otherwise according to the communication protocol). In
this embodiment, both AFE 202 and processor 206 are used as analyte
monitoring circuitry, but in other embodiments either circuit can
perform the analyte monitoring function. Processor 206 can include
one or more processors, microprocessors, controllers, and/or
microcontrollers, each of which can be a discrete chip or
distributed amongst (and a portion of) a number of different
chips.
[0090] A memory 203 is also included within ASIC 201 and can be
shared by the various functional units present within ASIC 201, or
can be distributed amongst two or more of them. Memory 203 can also
be a separate chip. Memory 203 can be volatile and/or non-volatile
memory. In this embodiment, ASIC 201 is coupled with power source
210, which can be a coin cell battery, or the like. AFE 202
interfaces with in vivo analyte sensor 104 and receives measurement
data therefrom and outputs the data to processor 206 in digital
form, which in turn processes the data to arrive at the end-result
glucose discrete and trend values, etc. This data can then be
provided to communication circuitry 208 for sending, by way of
antenna 211, to reader device 120 (not shown) where minimal further
processing is needed by the resident software application to
display the data.
[0091] FIG. 2C is similar to FIG. 2B but instead includes two
discrete semiconductor chips 212 and 214, which can be packaged
together or separately. Here, AFE 202 is resident on ASIC 212.
Processor 206 is integrated with power management circuitry 204 and
communication circuitry 208 on chip 214. AFE 202 includes memory
203 and chip 214 includes memory 205, which can be isolated or
distributed within. In one example embodiment, AFE 202 is combined
with power management circuitry 204 and processor 206 on one chip,
while communication circuitry 208 is on a separate chip. In another
example embodiment, both AFE 202 and communication circuitry 208
are on one chip, and processor 206 and power management circuitry
204 are on another chip. It should be noted that other chip
combinations are possible, including three or more chips, each
bearing responsibility for the separate functions described, or
sharing one or more functions for fail-safe redundancy.
[0092] Performance of the data processing functions within the
electronics of the sensor control device 102 provides the
flexibility for system 100 to schedule communication from sensor
control device 102 to reader device 120, which in turn limits the
number of unnecessary communications and can provide further power
savings at sensor control device 102.
[0093] Information may be communicated from sensor control device
102 to reader device 120 automatically and/or continuously when the
analyte information is available, or may not be communicated
automatically and/or continuously, but rather stored or logged in a
memory of sensor control device 102, e.g., for later output.
Accordingly, in many embodiments of system 100, analyte information
derived by sensor control device 102 is made available in a
user-usable or viewable form only when queried by the user such
that the timing of data communication is selected by the user.
[0094] Data can be sent from sensor control device 102 to reader
device 120 at the initiative of either sensor control device 102 or
reader device 120. For example, in some example embodiments sensor
control device 102 can communicate data periodically in a
broadcast-type fashion, such that an eligible reader device 120, if
in range and in a listening state, can receive the communicated
data (e.g., sensed analyte data). This is at the initiative of
sensor control device 102 because reader device 120 does not have
to send a request or other transmission that first prompts sensor
control device 102 to communicate. Broadcasts can be performed, for
example, using an active Wi-Fi, Bluetooth, or BTLE connection. The
broadcasts can occur according to a schedule that is programmed
within device 102 (e.g., about every 1 minute, about every 5
minutes, about every 10 minutes, or the like). Broadcasts can also
occur in a random or pseudorandom fashion, such as whenever sensor
control device 102 detects a change in the sensed analyte data.
Further, broadcasts can occur in a repeated fashion regardless of
whether each broadcast is actually received by a reader device
120.
[0095] System 100 can also be configured such that reader device
120 sends a transmission that prompts sensor control device 102 to
communicate its data to reader device 120. This is generally
referred to as "on-demand" data transfer. An on-demand data
transfer can be initiated based on a schedule stored in the memory
of reader device 120, or at the behest of the user via a user
interface of reader device 120. For example, if the user wants to
check his or her analyte level, the user could perform a scan of
sensor control device 102 using an NFC, Bluetooth, BTLE, or Wi-Fi
connection. Data exchange can be accomplished using broadcasts
only, on-demand transfers only, or any combination thereof.
[0096] Accordingly, once a sensor control device 102 is placed on
the body so that at least a portion of sensor 104 is in contact
with the bodily fluid and electrically coupled to the electronics
within device 102, sensor derived analyte information may be
communicated in on-demand or broadcast fashion from the sensor
control device 102 to a reader device 120. On-demand transfer can
occur by first powering on reader device 120 (or it may be
continually powered) and executing a software algorithm stored in
and accessed from a memory of reader device 120 to generate one or
more requests, commands, control signals, or data packets to send
to sensor control device 102. The software algorithm executed
under, for example, the control of processing hardware 226 of
reader device 120 may include routines to detect the position of
the sensor control device 102 relative to reader device 120 to
initiate the transmission of the generated request command, control
signal and/or data packet.
[0097] Different types and/or forms and/or amounts of information
may be sent as part of each on-demand or broadcast transmission
including, but not limited to, one or more of current analyte level
information (i.e., real time or the most recently obtained analyte
level information temporally corresponding to the time the reading
is initiated), rate of change of an analyte over a predetermined
time period, rate of the rate of change of an analyte (acceleration
in the rate of change), or historical analyte information
corresponding to analyte information obtained prior to a given
reading and stored in a memory of sensor control device 102.
[0098] Some or all of real time, historical, rate of change, rate
of rate of change (such as acceleration or deceleration)
information may be sent to reader device 120 in a given
communication or transmission. In certain embodiments, the type
and/or form and/or amount of information sent to reader device 120
may be preprogrammed and/or unchangeable (e.g., preset at
manufacturing), or may not be preprogrammed and/or unchangeable so
that it may be selectable and/or changeable in the field one or
more times (e.g., by activating a switch of the system, etc.).
Accordingly, in certain embodiments, reader device 120 will output
a current (real time) sensor-derived analyte value (e.g., in
numerical format), a current rate of analyte change (e.g., in the
form of an analyte rate indicator such as an arrow pointing in a
direction to indicate the current rate), and analyte trend history
data based on sensor readings acquired by and stored in memory of
sensor control device 102 (e.g., in the form of a graphical trace).
Additionally, an on-skin or sensor temperature reading or
measurement may be communicated from sensor control device 102 with
each data communication. The temperature reading or measurement,
however, may be used in conjunction with a software routine
executed by reader device 120 to correct or compensate the analyte
measurement output to the user by reader device 120, instead of or
in addition to actually displaying the temperature measurement to
the user.
[0099] US Patent Application Publication No. 2011/0213225 (the '225
Publication) generally describes components of an in vivo-based
analyte monitoring system that are suitable for use with the
authentication methods and hardware embodiments described herein.
The '225 Publication is incorporated by reference herein in its
entirety for all purposes. For other examples of sensor control
device 102 and reader device 120, see, e.g., devices 102 and 120,
respectively, as described in the incorporated '225
Publication.
Example Embodiments of Authentication Systems, Devices, and
Methods
[0100] In many conventional in vivo systems, the sensor control
device and reader device communicate with each other over a
proprietary wireless protocol that cannot easily be deciphered by
third parties. The presence of this proprietary wireless protocol
acts as a barrier to the usage of unauthorized sensor control or
reader devices within the in vivo system.
[0101] However, with the integration of in vivo monitoring software
into commercially available communication devices like smart phones
and the use of those smart phones to communicate with the sensor
control device using well known communication protocols (e.g.,
Wi-Fi, NFC, RFID, Bluetooth, BTLE, etc.), the proprietary
communication link can no longer act as a de facto technique for
authentication. Accordingly, other techniques and hardware for
authentication are required.
[0102] A number of example embodiments of enhanced systems,
devices, and methods for providing authentication are described
herein. In these embodiments, the device being authenticated will
most commonly be sensor control device 102. It should be
understood, however, that the techniques and features described
herein can also be used to authenticate other devices and
components of system 100 other than sensor control device 102. For
instance, in certain embodiments, reader device 120 can be
authenticated using similar techniques and features to those
described herein.
[0103] Generally, to operate in vivo monitoring system 100, a user
will first remove, or cause to be removed, sensor control device
102 from sterile packaging. Sensor control device 102 can then be
placed on the user's body such that sensor 104 is in contact with
the user's body fluid. As mentioned, this can be done with the aid
of an inserter 150. In many embodiments, sensor control device 102
will be activated as will reader device 120. A connection will also
be established between sensor control device 102 and reader device
120 so that they may exchange data and information. These events
can occur in a number of different sequences. For instance,
activation of sensor control device 102 can occur prior to removal
from packaging, upon the removal from packaging, or subsequent to
the removal from packaging (either before or after placement on the
user's body). Activation of reader device 120 can also occur at any
of those times. Reader device 120, in some embodiments can be a
smart phone, in which case it will likely have been activated long
before activation of sensor control device 102. In fact, reader
device 120 may have interfaced with any number of sensor control
devices 102 prior to the current one. By way of further example,
the connection between sensor control device 102 and reader device
120 can be established prior to the removal of sensor control
device 102 from its packaging, upon the removal of sensor control
device 102 from its packaging, or subsequent to the removal of
sensor control device 102 from its packaging (either before or
after placement of sensor control device 102 on the user's
body).
[0104] Authentication of sensor control device 102 can also occur
at any time during the usage of that sensor control device 102. For
instance, authentication can occur prior to the removal of sensor
control device 102 from its packaging, upon removal of sensor
control device 102 from its packaging, or subsequent to removal of
sensor control device 102 from its packaging (either before or
after placement of sensor control device 102 on the user's body).
Authentication can occur during the establishment of a connection
between sensor control device 102 and reader device 120, for
example, during or immediately after the pairing of sensor control
device 102 with reader device 120 if a pairing procedure is used,
such as with a Bluetooth protocol. Authentication can occur after
establishing a connection between sensor control device 102 and
reader device 120 but prior to the monitoring of analyte levels by
sensor control device 102, or prior to the reception of those
monitored analyte levels by reader device 120.
[0105] In still other embodiments, authentication can occur after
sensor control device 102 has monitored the analyte levels,
transferred those analyte levels to reader device 120, and reader
device 120 has displayed those analyte levels to the user or
otherwise communicated them to the user or to another computer
system for display and/or analysis. In most embodiments, the
purpose of authentication of sensor control device 102 is to detect
the presence of counterfeit sensor control devices and prevent
their usage in system 100, meaning that authentication provides the
greatest benefits when it occurs prior to actual use of sensor
control device 102 to measure and/or communicate measured analyte
levels of the user. Thus, while delay in the authentication process
is permissible, it may not be the most desirable (depending on the
implementation).
[0106] The authentication process can be initiated by either sensor
control device 102 or reader device 120. For instance, reader
device 120 can send an identification request or command to sensor
control device 102 so that sensor control device 102 can initiate
the authentication process, for instance, by sending authentication
information to reader device 120. The identification request or
command need not be dedicated for the purpose of initiating the
authentication process. Rather, the request or command can instead
be data, e.g., header or payload data, that is used primarily for
other purposes but is interpreted, e.g., upon initial receipt, as a
trigger for the sending of authentication information by sensor
control device 102.
[0107] Alternatively, sensor control device 102 can initiate the
authentication process by automatically supplying authentication
information to reader device 120 without having received a prior
request to do so. Sensor control device 102 may broadcast
authentication information upon activation, or upon establishing a
connection with reader device 120, upon receiving a first
communication from reader device 120, or the like. Sensor control
device 102 can also be configured to continuously send
authentication information until the receipt of an acknowledgment
from reader device 120. Sensor control device 102 may include
authentication information within all (or most) communications as a
matter of course, to allow reader device 120 to read the
authentication information when desired, and also to allow multiple
reader devices 120 to operate with sensor control device 102
without having to send multiple authentication information
requests.
[0108] FIG. 3A is an illustration depicting an example embodiment
of in vivo analyte monitoring system 100. Here, sensor control
device 102 is in communication with reader device 120 over a local
wireless communication path 140. Reader device 120 is in
communication with trusted computer system 180 over communication
path 142, which in this embodiment is the internet. Sensor control
device 102 includes a memory (e.g., memory 203 and/or 205 as shown
in FIGS. 2B-C) that stores authentication information about sensor
control device 102. This authentication information can, in certain
embodiments, uniquely identify sensor control device 102 such that
no two sensor control devices 102 (within the same product line)
share the same authentication information. In many embodiments, the
authentication information is an identification (ID) number of
sensor control device 102 or sensor 104 (also referred to herein as
an "identifier"), e.g., a serial number, that is assigned to sensor
control device 102 and stored within memory 203 and/or 205 during
the manufacturing or post manufacturing process. Identifiers 304
can be chosen as a non-sequential, random, or pseudo-random string
of characters (alphanumeric or otherwise) to minimize the risk that
a counterfeiter will be able to forecast or correctly guess future
identifiers 304.
[0109] FIG. 3A depicts system 100 with the sending of
communications at different points in time. For example, reader
device 120 first transmits communication 301 (or transmission,
message, packet, etc.), containing an authentication request 302,
to sensor control device 102 over communication path 140. After
receiving and reading authentication request 302, sensor control
device 102 can send a communication 303, containing identifier 304,
back to reader device 120 over path 140. Reader device 120, after
receiving identifier 304, can optionally perform a first
verification to ensure that identifier 304 is in the proper format
or that identifier 304 does not belong to a class of devices (e.g.,
prior models) that are not for operation with reader device
120.
[0110] Reader device 120 can then transmit a communication 305,
containing identifier 304 (in the same or a different format from
that received), over communication path 142 to trusted computer
system 180. Trusted computer system 180 includes computer hardware
that is programmed to read the received identifier 304 and compare
it to a compilation of identifiers stored therewith, such as within
registration database 181. The compilation can be in any desired
form, including but not limited to a data structure, table, list,
array, and the like. The compilation can also be contiguous or
non-contiguous, e.g., spread across multiple data structures. In
certain embodiments, each identifier stored within registration
database 181 is associated with an indication as to whether that
identifier correlates to a sensor control device 102 that has
already been used.
[0111] FIG. 3B depicts an example of a compilation 182 of
identifiers 304 in a table format. In most embodiments, compilation
304 would be stored in a computer readable format different from
the human readable format shown here. Each identifier 304 is
contained within one of two separate lists: a first list 184 of
identifiers 304 that are associated with sensor control devices 102
that have already been used; or a second list 186 of identifiers
304 that are associated with sensor control devices 102 that have
not yet been used. Trusted computer system 180 can consult the
compilation of unused sensor control devices 102 first and the
compilation of used sensor control devices 102 second or
vice-versa.
[0112] Alternatively, compilation 182 can include only unused
identifiers 304, where a failure to locate the received identifier
304 within that compilation corresponds to a conclusion that the
received identifier 304 is associated with an already used sensor
control device 102, a sensor control device 102 that is not
authorized for use with reader device 120, or a sensor control
device 102 that is counterfeit. Once a particular identifier 304 is
located within the compilation it would then be removed. Of course,
a reverse scheme can also be implemented where compilation 182 only
includes used identifiers 304.
[0113] Should a received identifier 304 be located on list 186,
then trusted computer system 180 associates that received
identifier 304 with a sensor control device 102 that is authentic
(e.g., not made by a different manufacturer), or authorized for use
by the user with reader device 120. Trusted computer system 180
then generates an authentication result 306 that authorizes the use
of sensor control device 102 and transmits that authentication
result 306 in communication 307 over communication path 142 to
reader device 120. Authentication result 306 can be one or more
bits of data (e.g., a flag or notification) that indicate whether
or not sensor control device 102 is permitted for use, and also
optionally any other related information, such as the reason(s) for
a failure to authenticate. Authentication result 306 can be
interpreted by reader device 120 as a command to continue or to
stop operation with sensor control device 102.
[0114] Trusted computer system 180 also revises compilation 182
such that the received identifier 304 is then associated with a
used sensor control device 102. In this embodiment, this would
entail moving that identifier 304 from list 186 to list 184. Reader
device 120 receives and reads the authentication result 306,
thereby becoming informed that sensor control device 102 is an
authentic device.
[0115] Reader device 120 can then optionally display the positive
authentication result to the user. Reader device 120 can be
programmed to then initiate (or, alternatively, to then continue)
normal operation with sensor control device 102, such as by
receiving monitored analyte data from sensor control device 102 and
displaying that information, e.g., in the form of a glucose level,
to the user.
[0116] Alternatively, should a received identifier 304 be located
on list 184, then trusted computer system 180 associates that
received identifier with a sensor control device 102 that is not
authentic, or not authorized for use by the user with reader device
120. In such an instance, it is possible that sensor control device
102 is an unused counterfeit device, that sensor control device 102
had already been used once and an attempt is being made to reuse
that same sensor control device 102, or that sensor control device
102 is a refurbished or recycled device. Other possibilities may
also exist. Trusted computer system 180 then generates an
authentication result 306 that indicates that the use of sensor
control device 102 is not permitted or authorized, and transmits
that negative authentication result 306 over communication path 142
to reader device 120. Reader device 120 receives and reads the
authentication result 306, thereby becoming informed that sensor
control device 102 is not authorized. Reader device 120 can be
programmed to then cease operation with sensor control device 102,
or otherwise prevent the use of that particular sensor control
device 102. Reader device 120 can optionally display the negative
authentication result to the user and instruct the user to remove
sensor control device 102 if it has already been applied to the
user's body. Reader device 120 can optionally inform the user that
the sensor control device is a counterfeit device.
[0117] In some embodiments, reader device 120 includes local
positioning capability that determines its geographic position.
Because the reader device 120 is typically used in close proximity
with sensor control device 102, e.g., by the same user, it can be
assumed that sensor control device 102 will have the same
geographic location has reader device 120. Referring back to FIG.
3A, reader device 120 can transmit current location information
along with identifier 304 in communication 305. The current
location information can be used by trusted computer system 180 to
assess whether sensor control device 102 is being used within an
authorized geographic region. Authorized geographic regions can be
segmented on the basis of continents, nations, or other regions as
desired. Such an assessment can help ensure that sensor control
device 102 is used only in regions where the device has regulatory
or other requisite governmental approval.
[0118] FIG. 3C depicts an example embodiment of compilation 182
having regional information further included therein. In this
embodiment, list 186 includes those identifiers 304 that are
associated with unused sensor control devices 102 within a first
partition 187 and those regions in which the corresponding sensor
control device 102 is approved for use within a second partition
188. Thus, if identifier 304 is located by system 180 within
partition 187 of list 186, then system 180 can further compare the
received location information with the approved regions in
partition 188. If it is determined that the current location of the
unused sensor control device 102 is within an approved region, then
trusted computer system 180 can generate a positive authentication
result 306 (an approval indication) and transmit that positive
authentication result 306 to reader device 120. Reader device 120
can then treat sensor control device 102 as an authorized device.
Should it be determined that the current location of the unused
sensor control device 102 is not within an approved region, then
trusted computer system 180 can generate a negative authentication
result 306 (withheld authorization) and transmit that result 306 to
reader device 120.
[0119] Alternatively, system 180 can generate a hybrid
authentication result 306 that indicates that sensor control device
102 is authentic but not in the proper region. Reader device 120
can be programmed to allow temporary use of sensor control device
102 in the improper region, for example, if the user is traveling.
Reader device 120 can cease operation with sensor control device
102 and, optionally display or otherwise communicate that result to
the user.
[0120] In other embodiments, reader device 120 can locally store
information that correlates particular sensor control devices 102
with the regions in which they are approved for use. In those
cases, reader device 120 can locally determine whether a particular
sensor control device 102 is approved for use in a particular
region without having to communicate first with another computer
system over the internet to obtain that authorization.
[0121] FIG. 3D is an illustration depicting another example
embodiment of system 100. This embodiment is similar to that
described with respect to FIG. 3A except that reader device 120
locally stores a registration database 129 (similar to registration
database 181) and can use registration database 129 to perform an
authentication of sensor control device 102 without the need for an
internet connection to a remote network having trusted computer
system 180. Thus, reader device 120 need not always have internet
access to perform authentication, thereby allowing the user added
flexibility in using system 100. Database 129 is stored within the
local memory (e.g., memory 263 as depicted in FIG. 2B) of reader
device 120, for example, during manufacturing, and can be accessed
at any time. Similar to the embodiments described above, reader
device 120 can, optionally, first send an authentication request
302 to sensor control device 102 in communication 301. Sensor
control device 102 can then respond with identifier 304 in
communication 303. After receiving identifier 304, reader device
120 can consult database 129 to determine if identifier 304 is
associated with a used or unused device in a manner similar to that
described with respect to FIGS. 3A-C.
[0122] Local registration database 129 can be updated once an
internet connection is established by reader device 120. In another
embodiment, new sensor control devices 102 (e.g., individually or
in a multi-pack) can be provided to users with updates to local
registration database 129 stored therein, where those updates are
subsequently communicated wirelessly or otherwise uploaded to
reader device 120. In yet another embodiment, the updates to
database 129 can be provided with new sensor control devices 102 by
way of barcodes or NFC (or RFID) elements that contain the updates
and can provide the update to reader device 120 through a
corresponding optical, NFC, or RFID scan.
[0123] In an update, identifiers 304 associated with newly
manufactured sensor control devices 102 can be appended to database
129, and those sensor control devices 102 that were marked as
unused within database 129, which have recently been used by a
user, can be updated accordingly within database 129. In addition,
when an internet connection is established, reader device 120 can
report the fact that identifier 304 of the current sensor control
device 102 has now been used to trusted computer system 180 so that
it may update database 181 and report the same to other reader
devices 120 in the field.
[0124] In certain embodiments, database 181 acts as a master
database that can be used to resolve any conflicts between
databases 129 of reader devices 120 in the field. Trusted computer
system 180 can also send a message or command to a particular
reader device 120 that has been used with a counterfeit or
unauthorized sensor control device 102 that instructs that reader
device 120 to establish an internet connection prior to commencing
normal operation (e.g., reading and reporting sensed analyte data)
with any future sensor control devices 102. This can effectively
designate those reader devices 120 that have been used with
counterfeit sensor control devices 102 as higher risk devices that
may be more likely to be used with counterfeit sensor control
devices 102 in the future. The more stringent safeguard is the
requirement that those reader devices 120 establish an interconnect
connection and perform an authentication procedure with trusted
computer system 180 prior to commencing normal operation with any
particular sensor control device 102.
[0125] FIGS. 4 and 5A-B are illustrations depicting additional
example embodiments of system 100 and the use thereof In these
embodiments, system 100 utilizes both an identifier 304 and a token
402. Token 402, in most embodiments, is a unique value associated
with identifier 304 for a particular sensor control device 102
during the manufacturing process, and is stored together with
identifier 304 within the memory of sensor control device 102. In
many cases, one and only one token 402 is associated with each
identifier 304. However, in some instances it may be desirable to
associate multiple tokens 402 with a single identifier 304, or
multiple identifiers 304 with a single token 402. Token 402 can be
chosen as a non-sequential, random, or pseudo-random string of
characters (alphanumeric or otherwise) to minimize the risk that a
third party will be able to forecast or correctly guess future
tokens 402.
[0126] Generally, for purposes of authentication, the identifier
304 and token 402 are obtained from a particular sensor control
device 102 (or its packaging, etc.) and input into reader 120. This
obtained identifier 304 can then be used as an index to look up and
retrieve a corresponding token 402 from a registration database,
and this retrieved token 402 is compared with the token 402
obtained from the particular sensor control device 102 to determine
if they match. A match can be treated as authentication of the
sensor control device 102, and a mismatch can be treated as
indicative of a counterfeit, reused, recycled, refurbished, or
otherwise unauthorized sensor control device 102.
[0127] These embodiments may find particular suitability in
implementations where identifier 304 is a non-random (e.g.,
sequential) serial number of the sensor control device 102 that
might be predictable to a third party. The use of an additional
random, non-sequential string of characters in the form of token
402 makes it more difficult, if not impossible, for third parties
to accurately predict the token and forge sensor control devices
102.
[0128] Token 402 can be provided to reader device 120 in a number
of different ways. In the embodiment of FIG. 4, token 402 is
provided directly to reader 120 by sensor control device 102. Like
the embodiments described with respect to FIGS. 3A and 3D, reader
device 120 can send an identifier request 302 to sensor control
device 102 in communication 301. Sensor control device 102 can
respond by retrieving both an identifier 304 and a token 402 from
memory and communicating the identifier 304 and token 402 to reader
device 120 in communication 404. Reader device 120 can then send
identifier 304 and token 402 to trusted computer system 180 in
communication 406.
[0129] Trusted computer system 180 can verify the received
identifier 304 against registration database 181 in a manner
similar to that already described. In addition, or in the
alternative, trusted computer system 180 can use identifier 304 as
an index to locate and retrieve a token 402 that was associated
with that specific identifier 304 by the manufacturer, for example,
during the manufacturing process. Token 402 can be stored within
database 181 as a data element associated with identifier 304
within a particular data structure, or in separate memory located
outside of database 181 (within trusted computer system 180 or
elsewhere).
[0130] The token 402 that is retrieved from database 181 can then
be compared to the token 402 provided by reader device 120. If the
two tokens 402 match, a positive authentication result 306 is
generated and transmitted to reader device 120 in communication
408. Reader device 120 can be programmed to commence or continue
normal operation with sensor control device 120 if a positive
authentication result 306 is received. If the two tokens 402 do not
match, then it is possible that sensor control device 120 is a
counterfeit device (or a reused, refurbished, or recycled device,
etc.) and authorization is withheld. A negative authentication
result 306 is generated and transmitted to reader device 120 (in
communication 408) instructing it to cease or terminate normal
operation with sensor control device 102. Reader device 120 can,
optionally, instruct the user of the same.
[0131] FIGS. 5A-B depict an alternative embodiment where token 402
is not provided directly by sensor control device 102, but rather
is obtained indirectly with the assistance of the user. In FIG. 5A,
sensor control device 102 is depicted within packaging 501.
Packaging 501 includes a code 502 such as printed barcode 502 with
information corresponding to token 402. An optical scanner 505
(e.g., a camera) of reader device 120 can optically scan barcode
502 to retrieve token 402.
[0132] Packaging 501 can be a container for any part of system 100
that is supplied to the user, and is not limited to the container
for the actual sensor control device 102, itself. Packaging 501 can
be a container for sensor control device 102 alone, a container for
multiple sensor control devices 102 (e.g., a multi-pack), a
container for sensor control device 102 in combination with
inserter 150 (FIG. 1), a container for inserter 150 alone, and can
refer to inserts, labels, instructions, manuals, or the like that
are contained within or otherwise shipped with system 100. Barcode
502 is shown here as a two-dimensional barcode. Barcode 502 can
also be a one-dimensional barcode, three-dimensional barcode and
can be of any format (QR code, data matrix, maxicode, aztec code,
QR code, etc.). Printed indicia other than barcodes can be used as
well.
[0133] Any number of additional techniques can be used to provide
token 402 to reader device 120. For example, token 402 can be
printed in human readable form on package 501, e.g., on a
holographic label, such that the user can manually enter token 402
into reader device 120. In another example, token 402 is stored in
an RFID (or NFC) label on packaging 501 and is read using an RFID
(or NFC) scanner that is part of reader device 120. Many smart
phones that can serve as reader devices 120 are equipped with RFID
or NFC scanners that can read such labels. Other machine-readable
formats can be used to obtain token 402 from packaging 501 as well.
In all of the examples described herein, the provision of token 402
to reader device 120 can be done at a time of the user's choosing
or in response to a prompt to do so by reader device 120.
[0134] Turning to FIG. 5B, system 100 can be configured such that
reader device 120 sends a request 302 in communication 301 to
sensor control device 102 for an identifier 304. Sensor control
device 102 communicates identifier 304 to reader device 120 in
communication 303. Token 402 is provided to reader device 120 with
the assistance of the user, e.g., such as by scanning token 402
from packaging as depicted in FIG. 5A. This can occur prior to the
sending of communication 301, concurrently with the sending of
communications 301 or 303, or after the receipt of communication
303 by reader device 120. Regardless, after token 402 is provided
to reader device 120, it is forward to trusted computer system 180
in communication 406 and the authentication process continues
through completion as described with respect to FIG. 4.
[0135] In the embodiments of FIGS. 4 and 5A-B, registration
database 181 within the remotely located trusted computer system
180 can be used to verify that tokens 402 and identifiers 304 are
authentic. The embodiment described with respect to FIG. 4 can be
modified such that the various tokens 402 and identifiers 304 are
stored within a local registration database (e.g., database 129) of
reader device 120 in a manner similar to that described with
respect to the trusted computer system's registration database 181
(see, e.g., FIG. 3D).
[0136] In such a configuration, reader device 120 would perform
those tasks described with respect to FIG. 4 as being performed by
trusted computer system 180 (e.g., retrieval of identifier 304 from
the database and comparison with the identifier 304 obtained from
sensor control device 102 to determine if they match, using
identifier 304 as an index to locate token 402 within the database,
comparison of token 402 from the database with the token 402
obtained from sensor control device 102 to determine if they match,
optionally generating an authentication result, etc.). There would
no longer be a need to send communications 406 and 408, and the
need for an internet connection 142 would be obviated for purposes
of authenticating a particular sensor control device (although an
internet connection may be desired for other reasons, such as
providing updates as to used identifiers and tokens to trusted
computer system 180, so that updates can be disseminated to other
reader devices and instances of unauthorized usage can be
monitored, etc.).
[0137] In yet another embodiment, token 402 can be provided to
reader device 120 in a manner similar to that described with
respect to FIGS. 4 and 5A-B, but reader device 120 does not forward
token 402 to trusted computer system 180. Instead, reader device
sends only identifier 304 to trusted computer system 180, which can
then retrieve the corresponding version of token 402 stored within
registration database and send that retrieved version back to
reader device 120 (with or without authentication result 306).
Reader device 120 can then determine whether token 402 provided by
sensor control device 102 matches the token 402 received from
trusted computer system 180 and conclude whether or not sensor
control device 102 is authentic.
[0138] A number of additional embodiments will now be described
that make use of authentication techniques having multiple keys,
such as asymmetric (public key) cryptography and/or symmetric
cryptography. These embodiments can be used alone or with any of
the other embodiments, such as those using identifiers and/or
tokens, described herein.
[0139] In public key cryptography, both a public key and a private
key are typically used. The private key can be associated with
sensor control device 102 and the public key can be associated with
reader device 120. For example, one of any number of key generation
algorithms, which are known in the art, can be used to generate a
private key and a corresponding public key. Examples of key
generation algorithms that can be used include, but are not limited
to RSA algorithms such as those described in the Public-Key
Cryptography Standards (PKCS). Any desired key length can be used,
but keys with longer lengths will typically provide more security.
For example, key lengths of 128 bits, 256 bits, 512 bits, 1024
bits, 2048 bits, and 5096 bits, as well as others, can be used.
[0140] FIG. 6 depicts an example embodiment of system 100 utilizing
both a private key 602 and a public key 604. Here, sensor control
device packaging 501 has a barcode label 502 representing private
key 602, which can be in an encrypted format. Optical scanner 505
of reader device 120 scans the barcode on label 502 and retrieves
private key 602.
[0141] A public key 604 is stored within the memory of reader
device 120. After reader device 120 obtains private key 602 and
applies any required decryption algorithm to it, reader device 120
uses an algorithm stored thereon and public key 604 to
algorithmically verify whether private key 602 is an authentic key,
in accordance with techniques that will be readily apparent to
those of ordinary skill in the art. If private key 602 is verified
as authentic, then reader device 120 can initiate or continue
normal operation with sensor control device 102. Conversely, if
private key 602 is not verified as authentic, then it can be
assumed that sensor control device 102 is counterfeit or otherwise
not suitable for use, and reader device 120 ceases normal operation
with sensor control device 102. While private key 602 is shown and
described here as being optically represented on packaging 501 in
barcode format, it should be noted that private key 602 can be
associated with packaging 501 in any of the manners described with
respect to the embodiments of FIGS. 5A-B. Also, private key 602 can
be stored in the memory of sensor control device 102 during, for
instance, manufacturing, and obtained by reader device 120 by
communication over wired or wireless path 140.
[0142] In additional embodiments, private key 602 can be kept with
the manufacturer, for example, with trusted computer system 180,
and public key 604 can be stored in the memory of reader device 120
or sensor control device 102. In some embodiments, private key 602
can be used with a signing algorithm to generate a digital
signature (or to digitally sign data) that is stored within
non-volatile memory of sensor control device 102. Reader device 120
can be provided with this digital signature and can use public key
604 to algorithmically verify the authenticity of the signature. In
these embodiments, trusted computer system 180 can act as a
certificate authority (CA) or registration authority (RA) and can
include a central directory as a repository for generated private
keys, public keys, and/or digital signatures. The central directory
can be a database that is separate from registration database 181,
or it can be the same database.
[0143] Any desired technique or scheme that relies on public and
private keys (e.g., key generation algorithms, signing algorithms,
and signature verifying algorithms) can be used to implement the
systems, devices, and methods described herein. These include, but
are not limited to, techniques or schemes based on the RSA
algorithms (and their variants), El Gamal algorithms (and their
variants), Digital Signature Algorithm (DSA) (described in U.S.
Pat. No. 5,231,668, which is incorporated by reference herein for
all purposes) (and its variants), and elliptical curve-based
algorithms (and its variants), and Rabin algorithms (and its
variants).
[0144] In some embodiments, the digital signatures can be used with
or within digital certificates (also referred to as public key
certificates or identity certificates), for example, to bind a
public key stored within a reader device to the individual that
uses the reader device. The digital certificates can include any
combination of the following (or information representative of the
following): a serial number that uniquely identifies the digital
signature, a subject (e.g., the user identified), the signing
algorithm used to create signature, the digital signature itself,
and identification of the issuer of the certificate, a date from
which the certificate is first valid, a date to which the
certificate is valid (e.g., an expiration date), a purpose of the
public key, the public key itself, a thumbprint algorithm (the
algorithm used to hash the certificate, if certificate is hashed),
and the thumbprint (the hash itself, if used).
[0145] One such example embodiment using this approach is depicted
in FIG. 7. Here, reader device 120 can optionally send a signature
request 701 in communication 702 to sensor control device 102. In
response, sensor control device 102 retrieves digital signature 703
from memory and communicates it to reader device 120 in
communication 704. Reader device 120 can then perform a
verification of signature 703 using public key 604, which is stored
in the memory thereof. If the signature 703 is verified, reader
device 120 can initiate or continue normal operation with sensor
control device 102. Conversely, if signature 703 is determined to
not be authentic, e.g., signature 703 fails the verification
process, then reader device 120 can cease operation with sensor
control device 102 and inform the user of the same.
[0146] In some embodiments, calibration parameters are determined
for each sensor 104 during the manufacturing process and are stored
in non-volatile memory of sensor control device 102. Some examples
of these parameters are described in US Publication 2010/0230285,
which is incorporated by reference herein for this and all other
purposes. These calibration parameters can account for variations
in the manufacturing process, and/or time-varying parameters (e.g.,
drift) of the sensor 104, and can be used to compensate for those
variations and achieve accurate measurements of analyte levels. In
some embodiments, digital signature 703 can be obtained by using a
signing algorithm on private key 602 and the calibration parameters
(e.g., the signed data) for that particular sensor control device
102. Digital signature 703 can be stored in the memory of sensor
control device 102 along with a copy of those calibration
parameters. Both digital signature 703 and the calibration
parameters can be read from sensor control device 102 with reader
device 120.
[0147] Reader device 120 can then apply a signature verifying
algorithm to verify the authenticity of digital signature 703 and
retrieve the calibration parameters from signature 703. The
retrieved, unsigned calibration parameters can then be compared
with those that were read directly from sensor control device 102
to see if they match. Because calibration parameters typically vary
from sensor to sensor, a digital signature 703 that is copied from
an authentic sensor control device 102 and reproduced on a
counterfeit sensor control device 102 would contain calibration
parameters that would almost certainly not match the actual
calibration parameters stored within that sensor control device
102. Thus, counterfeiting would be deterred. Further, the
calibration parameters can play a significant role in achieving
accurate analyte measurements, and therefore a third-party would
not be able to use copied calibration parameters without
significantly compromising the accuracy of sensor control device
102. The matching of calibration parameters can be treated as
verification of the particular sensor control device 102, and
calibration parameters that differ can be treated as indicative of
a counterfeit device 102.
[0148] FIGS. 8A-C are flow diagrams depicting an example embodiment
of a method 800 of using system 100. In this embodiment, each
sensor control device 102 has an identifier 304 associated with it
that includes a serial number and a random number, where the random
number is used to increase the difficulty of predicting future
values of authentic identifiers by a third party. Here, steps 802
through 810 can be performed by the manufacturer or distributor of
system 100, or at least of sensor control device 102. In this
example, both an identifier verification process and a key
verification process are used, although it should be understood
that either may be used by itself without the other.
[0149] It should be understood that, while FIGS. 8A-C are shown
with steps occurring in a particular order, one of ordinary skill
in the art will readily recognize that it is not necessary that the
steps be performed in the specific order shown, and that variations
in the order of performance of the steps, including performing
steps simultaneously or with large periods of time in between, are
within the scope of the present disclosure.
[0150] At 802, an identifier 304, which in this example is a serial
number, is generated and assigned to the subject sensor control
device 102. At 804, a random number is generated and assigned to
the subject sensor control device 102. At 806, at least one key
pair is generated, including both a private key 602 and a public
key 604. In practice, a large number of keys may be generated
during this step. At 808, private key 602 is used with the serial
number and the random number to generate a digital signature 703,
which is stored on the subject sensor control device 102 at 809. It
should be noted that calibration parameters specific to sensor
control device 102 can be used instead of, or in addition to the
random number. Also, the serial number can be randomized to
alleviate the need for a separate random number. At 810, the serial
number, random number, key pair, and/or digital signature is
logged, for example, by providing it to registration database 181
where it can be used later during the identifier verification
process. Upon completing the manufacturing or configuration of
sensor control device 102, it is directly or indirectly distributed
to a user.
[0151] FIG. 8B depicts a compilation of steps or actions performed
with sensor control device 102 and reader device 120, and thus
would typically be performed by the user. Steps 812-828 are steps
that can (but not necessarily) be performed in real-time, e.g., as
the user is affirmatively interacting with sensor control device
102 and reader device 120 to set them up for operation, while steps
830-836 can be performed on a non-real-time basis, e.g., at a
scheduled time when the user is not otherwise interacting with the
system. At 812, the subject sensor control device 102 is activated
by the user. This may occur in a number of ways, e.g., by pressing
a switch, by unsealing device 102 from its packaging, by applying
device 102 to the body, etc. At 814, reader device 120 establishes
a connection with sensor control device 102 over communication path
140 (see, e.g., FIG. 1). While (or after) establishing the
connection, at 816, reader device 120 is provided with digital
signature 703 by sensor control device 102. Then, at 818, reader
device 120 uses public key 604, which was previously stored in the
memory of reader device 120, or was previously retrieved from the
manufacturer (e.g., over the internet from trusted computer system
180), in a signature verifying algorithm to reduce digital
signature 703 and obtain the serial number and random number
contained therein.
[0152] If it is desired to confer with trusted computer system 180
for authentication purposes (e.g., an internet connection is
available), then at 819 reader device 120 can transmit the serial
number to trusted computer system 180, which can receive it at 820.
Step 820 is depicted in FIG. 8C, which illustrates the steps that
can be performed at or with trusted computer system 180. Referring
still to FIG. 8C, at 821, trusted computer system 180 checks the
serial number against a compilation of used serial numbers and a
compilation of counterfeit serial numbers (which may be the same
compilation) that is stored within registration database 181 to see
if that serial number has been used already or is known (or
suspected) to be counterfeit.
[0153] At 822, trusted computer system 180 will transmit an
authentication result to reader device 120 indicating whether or
not that serial number is valid, e.g., suitable for use or not
counterfeit. If the serial number is valid, then at 823, trusted
computer system 180 can update registration database 181 to
indicate usage of that serial number. If the serial number is not
valid, then at 824 a system notification or alarm can be generated
to notify the administrator of trusted computer system 180 that a
potential counterfeiting has occurred, so that the incident can be
investigated accordingly. At 840, which may be a continuous act,
trusted computer system 180 can monitor transmissions from other
reader devices 120 in the field to determine if the valid serial
number is received from another source. If it is received, then
that can be indicative of counterfeiting. At 842, trusted computer
system 180 can transmit, or broadcast, an update to the reader
devices 120 associated with the counterfeit sensor control device
102 to notify them that such device is not (or no longer)
valid.
[0154] Referring back to FIG. 8B, if it is desired not to confer
with trusted computer system 180, e.g., no internet connection is
available or if it is desired to avoid performing an internet
transaction (such as to save time), etc., then at 825 reader device
120 can check the serial number against a local compilation of
serial numbers that indicates whether the serial numbers are used
or counterfeit (e.g., database 129). If the serial number is not
already used, or not suspected to be counterfeit, then, at 826,
reader device 120 can update the local compilation to indicate
usage of that serial number.
[0155] If it is determined that the serial number is not valid,
either through receipt of the authentication result from trusted
computer system 180 or through a local determination at reader
device 120, then, at 827 reader device 120 displays a message to
the user indicating the same and ceases operation with the subject
sensor control device 120. If it is determined that the serial
number is valid, then, at 828 reader device 120 continues with
normal operation with sensor control device 102, including the
collection and display of sensed analyte data from sensor control
device 102.
[0156] When an internet connection again becomes available, or at a
scheduled or convenient time, at 830, the serial number can be
uploaded to registration database 181 so that it can be added to
the compilation of used serial numbers stored therein. Also, at
832, an updated list of used serial numbers and/or suspected
counterfeit serial numbers can be downloaded from registration
database 181 and stored locally on reader device 120. If it is
later determined or suspected that the serial number of sensor
control device 102 is a counterfeit, then trusted computer system
180 can send a notification or alarm to reader device 120
indicating that the sensor control device is no longer authorized
for use (e.g., 842 in FIG. 8C), which can be received by reader
device 120 at 834 (FIG. 8B). At 836, a notification that a
counterfeit device is being used is displayed or otherwise
communicated to the user. An acknowledgment by the user that this
notification has been read and understood may be required prior to
terminating operation with the counterfeit sensor control device
102.
[0157] It should be understood that, for all of the example
embodiments described herein where communications are sent from
reader device 120 to trusted computer system 180 over the internet
for the purposes of authentication, those embodiments can be
modified such that the authentication information stored at trusted
computer system 180 (e.g., information stored within registration
database 181) is instead stored within reader device 120, and
reader device 120 can perform the authentication processes itself.
In these cases, reader device 120 can later verify its
determination as to the authenticity of sensor control device 102
by communication with trusted computer system 180, either by having
trusted computer system 180 conduct its own verification, or by
downloading relatively more current authentication information from
trusted computer system 180 and re-verifying the authenticity of
sensor control device 102. Likewise, for all of the example
embodiments described herein where reader device 120 performs its
own authentication of sensor control device 102 without
communication over the internet (e.g., by reference to a locally
stored registration database), these embodiments can be modified
such that reader device 120 instead relies upon trusted computer
system 180 to perform the authentication of sensor control device
102 by communicating the requisite authentication information to
trusted computer system 180 over the internet and by receiving an
authentication result from trusted computer system 180.
[0158] For each embodiment disclosed herein, software and other
mechanisms can be provided for logging and monitoring instances
where the authentication process results in a sensor control device
not being authenticated, in order to identify similarities and/or
patterns that can be indicative of localized, widespread, or
systematic abuse. For example, repeated use of the same identifier
in a particular region can be indicative of counterfeiting within
that region, in which case the manufacturer can take corrective
steps. The logging and/or monitoring function can be performed by
trusted computer system 180 (or an administrator thereof), reader
device 120, or another device or system. In addition to the region
of sale or use, instances of unauthorized usage can be correlated
to the identifier, token, private or public key, identity of the
user, identity of the distributor, identity of the hospital or
medical professional, model number of the sensor control device or
reader device, serial number of the sensor control device or reader
device, network address (e.g., IP address) of the reader device,
insurer, insurance account, any combination of two or more of the
aforementioned types of information, and the like.
Sensor Configurations
[0159] Analytes that may be monitored with system 100 include, but
are not limited to, acetyl choline, amylase, bilirubin,
cholesterol, chorionic gonadotropin, glycosylated hemoglobin
(HbA1c), creatine kinase (e.g., CK-MB), creatine, creatinine, DNA,
fructosamine, glucose, glucose derivatives, glutamine, growth
hormones, hormones, ketones, ketone bodies, lactate, peroxide,
prostate-specific antigen, prothrombin, RNA, thyroid stimulating
hormone, and troponin. The concentration of drugs, such as, for
example, antibiotics (e.g., gentamicin, vancomycin, and the like),
digitoxin, digoxin, drugs of abuse, theophylline, and warfarin, may
also be monitored. In embodiments that monitor more than one
analyte, the analytes may be monitored at the same or different
times.
[0160] Analyte sensor 104 may include an analyte-responsive enzyme
to provide a sensing element. Some analytes, such as oxygen, can be
directly electrooxidized or electroreduced on sensor 104, and more
specifically at least on a working electrode (not shown) of a
sensor 104. Other analytes, such as glucose and lactate, require
the presence of at least one electron transfer agent and/or at
least one catalyst to facilitate the electrooxidation or
electroreduction of the analyte. Catalysts may also be used for
those analytes, such as oxygen, that can be directly
electrooxidized or electroreduced on the working electrode. For
these analytes, each working electrode includes a sensing element
proximate to or on a surface of a working electrode. In many
embodiments, a sensing element is formed near or on only a small
portion of at least a working electrode.
[0161] Each sensing element includes one or more components
constructed to facilitate the electrochemical oxidation or
reduction of the analyte. The sensing element may include, for
example, a catalyst to catalyze a reaction of the analyte and
produce a response at the working electrode, an electron transfer
agent to transfer electrons between the analyte and the working
electrode (or other component), or both.
[0162] A variety of different sensing element configurations may be
used. In certain embodiments, the sensing elements are deposited on
the conductive material of a working electrode. The sensing
elements may extend beyond the conductive material of the working
electrode. In some cases, the sensing elements may also extend over
other electrodes, e.g., over the counter electrode and/or reference
electrode (or counter/reference where provided). In other
embodiments, the sensing elements are contained on the working
electrode, such that the sensing elements do not extend beyond the
conductive material of the working electrode. In some embodiments a
working electrode is configured to include a plurality of spatially
distinct sensing elements. Additional information related to the
use of spatially distinct sensing elements can be found in U.S.
Provisional Application No. 61/421,371, entitled "Analyte Sensors
with Reduced Sensitivity Variation," which was filed on Dec. 9,
2010, and which is incorporated by reference herein in its entirety
and for all purposes.
[0163] The terms "working electrode", "counter electrode",
"reference electrode" and "counter/reference electrode" are used
herein to refer to conductive sensor components, including, e.g.,
conductive traces, which are configured to function as a working
electrode, counter electrode, reference electrode or a
counter/reference electrode respectively. For example, a working
electrode includes that portion of a conductive material, e.g., a
conductive trace, which functions as a working electrode as
described herein, e.g., that portion of a conductive material which
is exposed to an environment containing the analyte or analytes to
be measured, and which, in some cases, has been modified with one
or more sensing elements as described herein. Similarly, a
reference electrode includes that portion of a conductive material,
e.g., conductive trace, which function as a reference electrode as
described herein, e.g., that portion of a conductive material which
is exposed to an environment containing the analyte or analytes to
be measured, and which, in some cases, includes a secondary
conductive layer, e.g., a Ag/AgCl layer. A counter electrode
includes that portion of a conductive material, e.g., conductive
trace which is configured to function as a counter electrode as
described herein, e.g., that portion of a conductive trace which is
exposed to an environment containing the analyte or analytes to be
measured. As noted above, in some embodiments, a portion of a
conductive material, e.g., conductive trace, may function as either
or both of a counter electrode and a reference electrode. In
addition, "working electrodes", "counter electrodes", "reference
electrodes" and "counter/reference electrodes" may include
portions, e.g., conductive traces, electrical contacts, or areas or
portions thereof, which do not include sensing elements but which
are used to electrically connect the electrodes to other electrical
components.
[0164] Sensing elements that are in direct contact with the working
electrode, e.g., the working electrode trace, may contain an
electron transfer agent to transfer electrons directly or
indirectly between the analyte and the working electrode, and/or a
catalyst to facilitate a reaction of the analyte. For example, a
glucose, lactate, or oxygen electrode may be formed having sensing
elements which contain a catalyst, including glucose oxidase,
glucose dehydrogenase, lactate oxidase, or laccase, respectively,
and an electron transfer agent that facilitates the
electrooxidation of the glucose, lactate, or oxygen,
respectively.
[0165] In other embodiments the sensing elements are not deposited
directly on the working electrode, e.g., the working electrode
trace. Instead, the sensing elements may be spaced apart from the
working electrode trace, and separated from the working electrode
trace, e.g., by a separation layer. A separation layer may include
one or more membranes or films or a physical distance. In addition
to separating the working electrode trace from the sensing
elements, the separation layer may also act as a mass transport
limiting layer and/or an interferent eliminating layer and/or a
biocompatible layer.
[0166] In certain embodiments which include more than one working
electrode, one or more of the working electrodes may not have
corresponding sensing elements, or may have sensing elements that
do not contain one or more components (e.g., an electron transfer
agent and/or catalyst) needed to electrolyze the analyte. Thus, the
signal at this working electrode may correspond to background
signal which may be removed from the analyte signal obtained from
one or more other working electrodes that are associated with
fully-functional sensing elements by, for example, subtracting the
signal.
[0167] In certain embodiments, the sensing elements include one or
more electron transfer agents. Electron transfer agents that may be
employed are electroreducible and electrooxidizable ions or
molecules having redox potentials that are a few hundred millivolts
above or below the redox potential of the standard calomel
electrode (SCE). The electron transfer agent may be organic,
organometallic, or inorganic. Examples of organic redox species are
quinones and species that in their oxidized state have quinoid
structures, such as Nile blue and indophenol. Examples of
organometallic redox species are metallocenes including ferrocene.
Examples of inorganic redox species are hexacyanoferrate (III),
ruthenium hexamine, etc. Additional examples include those
described in U.S. Pat. Nos. 6,736,957, 7,501,053 and 7,754,093, the
disclosures of each of which are incorporated herein by reference
in their entirety.
[0168] In certain embodiments, electron transfer agents have
structures or charges which prevent or substantially reduce the
diffusional loss of the electron transfer agent during the period
of time that the sample is being analyzed. For example, electron
transfer agents include but are not limited to a redox species,
e.g., bound to a polymer which can in turn be disposed on or near
the working electrode. The bond between the redox species and the
polymer may be covalent, coordinative, or ionic. Although any
organic, organometallic or inorganic redox species may be bound to
a polymer and used as an electron transfer agent, in certain
embodiments the redox species is a transition metal compound or
complex, e.g., osmium, ruthenium, iron, and cobalt compounds or
complexes. It will be recognized that many redox species described
for use with a polymeric component may also be used, without a
polymeric component.
[0169] Embodiments of polymeric electron transfer agents may
contain a redox species covalently bound in a polymeric
composition. An example of this type of mediator is
poly(vinylferrocene). Another type of electron transfer agent
contains an ionically-bound redox species. This type of mediator
may include a charged polymer coupled to an oppositely charged
redox species. Examples of this type of mediator include a
negatively charged polymer coupled to a positively charged redox
species such as an osmium or ruthenium polypyridyl cation.
[0170] Another example of an ionically-bound mediator is a
positively charged polymer including quaternized poly (4-vinyl
pyridine) or poly(1-vinyl imidazole) coupled to a negatively
charged redox species such as ferricyanide or ferrocyanide. In
other embodiments, electron transfer agents include a redox species
coordinatively bound to a polymer. For example, the mediator may be
formed by coordination of an osmium or cobalt 2,2'-bipyridyl
complex to poly(1-vinyl imidazole) or poly(4-vinyl pyridine).
[0171] Suitable electron transfer agents are osmium transition
metal complexes with one or more ligands, each ligand having a
nitrogen-containing heterocycle such as 2,2'-bipyridine,
1,10-phenanthroline, 1-methyl, 2-pyridyl biimidazole, or
derivatives thereof. The electron transfer agents may also have one
or more ligands covalently bound in a polymer, each ligand having
at least one nitrogen-containing heterocycle, such as pyridine,
imidazole, or derivatives thereof. One example of an electron
transfer agent includes (a) a polymer or copolymer having pyridine
or imidazole functional groups and (b) osmium cations complexed
with two ligands, each ligand containing 2,2'-bipyridine,
1,10-phenanthroline, or derivatives thereof, the two ligands not
necessarily being the same. Some derivatives of 2,2'-bipyridine for
complexation with the osmium cation include but are not limited to
4,4'-dimethyl-2,2'-bipyridine and mono-, di-, and
polyalkoxy-2,2'-bipyridines, including
4,4'-dimethoxy-2,2'-bipyridine. Derivatives of 1,10-phenanthroline
for complexation with the osmium cation include but are not limited
to 4,7-dimethyl-1,10-phenanthroline and mono, di-, and
polyalkoxy-1,10-phenanthrolines, such as
4,7-dimethoxy-1,10-phenanthroline. Polymers for complexation with
the osmium cation include but are not limited to polymers and
copolymers of poly(1-vinyl imidazole) (referred to as "PVI") and
poly(4-vinyl pyridine) (referred to as "PVP"). Suitable copolymer
substituents of poly(1-vinyl imidazole) include acrylonitrile,
acrylamide, and substituted or quaternized N-vinyl imidazole, e.g.,
electron transfer agents with osmium complexed to a polymer or
copolymer of poly(1-vinyl imidazole).
[0172] Embodiments may employ electron transfer agents having a
redox potential ranging from about -200 mV to about +200 mV versus
the standard calomel electrode (SCE). The sensing elements may also
include a catalyst which is capable of catalyzing a reaction of the
analyte. The catalyst may also, in some embodiments, act as an
electron transfer agent. One example of a suitable catalyst is an
enzyme which catalyzes a reaction of the analyte. For example, a
catalyst, including a glucose oxidase, glucose dehydrogenase (e.g.,
pyrroloquinoline quinone (PQQ), dependent glucose dehydrogenase,
flavine adenine dinucleotide (FAD) dependent glucose dehydrogenase,
or nicotinamide adenine dinucleotide (NAD) dependent glucose
dehydrogenase), may be used when the analyte of interest is
glucose. A lactate oxidase or lactate dehydrogenase may be used
when the analyte of interest is lactate. Laccase may be used when
the analyte of interest is oxygen or when oxygen is generated or
consumed in response to a reaction of the analyte.
[0173] In certain embodiments, a catalyst may be attached to a
polymer, cross linking the catalyst with another electron transfer
agent, which, as described above, may be polymeric. A second
catalyst may also be used in certain embodiments. This second
catalyst may be used to catalyze a reaction of a product compound
resulting from the catalyzed reaction of the analyte. The second
catalyst may operate with an electron transfer agent to electrolyze
the product compound to generate a signal at the working electrode.
Alternatively, a second catalyst may be provided in an
interferent-eliminating layer to catalyze reactions that remove
interferents.
[0174] In certain embodiments, the sensor works at a low oxidizing
potential, e.g., a potential of about +40 mV vs. Ag/AgCl. These
sensing elements use, for example, an osmium (Os)-based mediator
constructed for low potential operation. Accordingly, in certain
embodiments the sensing elements are redox active components that
include: (1) osmium-based mediator molecules that include (bidente)
ligands, and (2) glucose oxidase enzyme molecules. These two
constituents are combined together in the sensing elements of the
sensor.
[0175] A mass transport limiting layer (not shown), e.g., an
analyte flux modulating layer, may be included with the sensor to
act as a diffusion-limiting barrier to reduce the rate of mass
transport of the analyte, for example, glucose or lactate, into the
region around the working electrodes. The mass transport limiting
layers are useful in limiting the flux of an analyte to a working
electrode in an electrochemical sensor so that the sensor is
linearly responsive over a large range of analyte concentrations
and is easily calibrated. Mass transport limiting layers may
include polymers and may be biocompatible. A mass transport
limiting layer may provide many functions, e.g., biocompatibility
and/or interferent-eliminating functions, etc. A mass transport
limiting layer may be applied to an analyte sensor as described
herein via any of a variety of suitable methods, including, e.g.,
dip coating and slot die coating.
[0176] In certain embodiments, a mass transport limiting layer is a
membrane composed of crosslinked polymers containing heterocyclic
nitrogen groups, such as polymers of polyvinylpyridine and
polyvinylimidazole. Embodiments also include membranes that are
made of a polyurethane, or polyether urethane, or chemically
related material, or membranes that are made of silicone, and the
like.
[0177] A membrane may be formed by crosslinking in situ a polymer,
modified with a zwitterionic moiety, a non-pyridine copolymer
component, and optionally another moiety that is either hydrophilic
or hydrophobic, and/or has other desirable properties, in an
alcohol-buffer solution. The modified polymer may be made from a
precursor polymer containing heterocyclic nitrogen groups. For
example, a precursor polymer may be polyvinylpyridine or
polyvinylimidazole. Optionally, hydrophilic or hydrophobic
modifiers may be used to "fine-tune" the permeability of the
resulting membrane to an analyte of interest. Optional hydrophilic
modifiers, such as poly (ethylene glycol), hydroxyl or polyhydroxyl
modifiers, may be used to enhance the biocompatibility of the
polymer or the resulting membrane.
[0178] A membrane may be formed in situ by applying an
alcohol-buffer solution of a crosslinker and a modified polymer
over the enzyme-containing sensing elements and allowing the
solution to cure for about one to two days or other appropriate
time period. The crosslinker-polymer solution may be applied over
the sensing elements by placing a droplet or droplets of the
membrane solution on the sensor, by dipping the sensor into the
membrane solution, by spraying the membrane solution on the sensor,
and the like. Generally, the thickness of the membrane is
controlled by the concentration of the membrane solution, by the
number of droplets of the membrane solution applied, by the number
of times the sensor is dipped in the membrane solution, by the
volume of membrane solution sprayed on the sensor, or by any
combination of these factors. In order to coat the distal and side
edges of the sensor, the membrane material may have to be applied
subsequent to singulation of the sensor precursors. In some
embodiments, the analyte sensor is dip-coated following singulation
to apply one or more membranes. Alternatively, the analyte sensor
could be slot-die coated wherein each side of the analyte sensor is
coated separately. A membrane applied in the above manner may have
any combination of the following functions: (1) mass transport
limitation, i.e., reduction of the flux of analyte that can reach
the sensing elements, (2) biocompatibility enhancement, or (3)
interferent reduction.
[0179] In some embodiments, a membrane composition for use as a
mass transport limiting layer may include one or more leveling
agents, e.g., polydimethylsiloxane (PDMS). Additional information
with respect to the use of leveling agents can be found, for
example, in U.S. Patent Application Publication No. 2010/0081905,
the disclosure of which is incorporated by reference herein in its
entirety.
[0180] In some instances, the membrane may form one or more bonds
with the sensing elements. The term "bonds" is intended to cover
any type of an interaction between atoms or molecules that allows
chemical compounds to form associations with each other, such as,
but not limited to, covalent bonds, ionic bonds, dipole-dipole
interactions, hydrogen bonds, London dispersion forces, and the
like. For example, in situ polymerization of the membrane can form
crosslinks between the polymers of the membrane and the polymers in
the sensing elements. In certain embodiments, crosslinking of the
membrane to the sensing element facilitates a reduction in the
occurrence of delamination of the membrane from the sensor.
[0181] In many instances entities are described herein as being
coupled to other entities. It should be understood that the terms
"coupled" and "connected" (or any of their forms) are used
interchangeably herein and, in both cases, are generic to the
direct coupling of two entities (without any non-negligible (e.g.,
parasitic) intervening entities) and the indirect coupling of two
entities (with one or more non-negligible intervening entities).
Where entities are shown as being directly coupled together, or
described as coupled together without description of any
intervening entity, it should be understood that those entities can
be indirectly coupled together as well unless the context clearly
dictates otherwise.
[0182] While the embodiments are susceptible to various
modifications and alternative forms, specific examples thereof have
been shown in the drawings and are herein described in detail. It
should be understood, however, that these embodiments are not to be
limited to the particular form disclosed, but to the contrary,
these embodiments are to cover all modifications, equivalents, and
alternatives falling within the spirit of the disclosure.
Furthermore, any features, functions, steps, or elements of the
embodiments may be recited in or added to the claims, as well as
negative limitations that define the inventive scope of the claims
by features, functions, steps, or elements that are not within that
scope.
* * * * *