US6201980B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Implantable medical sensor system
Assignee: University of California
•
Filing: 1998-10-05
•
Granted: 2001-03-13
•
Expires: 2018-10-05
Abstract
Abstract An implantable chemical sensor system for medical applications is described which permits selective recognition of an analyte using an expandable biocompatible sensor, such as a polymer, that undergoes a dimensional change in the presence of the analyte. The expandable polymer is incorporated into an electronic circuit component that changes its properties (e.g., frequency) when the polymer changes dimension. As the circuit changes its characteristics, an external interrogator transmits a signal transdermally to the transducer, and the concentration of the analyte is determined from the measured changes in the circuit. This invention may be used for minimally invasive monitoring of blood glucose levels in diabetic patients.
Inventors
- 👤 Christopher B. Darrow
- 👤 Joe H. Satcher, Jr.
- 👤 Stephen M. Lane
- 👤 Abraham P. Lee
- 👤 Amy W. Wang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:26
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/0002; A61B5/0031; A61B5/145; A61B5/14532; A61B2562/00; A61B2562/02; A61B2562/028
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
82 words
An implantable chemical sensor system for measuring the concentration of an analyte of interest, comprising: a sensor, comprising a material that selectively responds to an analyte of interest by changing its dimensions; an implantable transducer, comprising an electronic circuit having at least one variable electrical characteristic that changes in response to dimensional changes of the sensor; and a telemetry device that interrogates the transducer transdermally to measure the changes in the electrical characteristic of the circuit as the concentration of analyte changes.
Claim 2
Dependent Claim
82 words
An implantable chemical sensor system for measuring the concentration of an analyte of interest, comprising: a sensor, comprising a material that selectively responds to an analyte of interest by changing its dimensions; an implantable transducer, comprising an electronic circuit having at least one variable electrical characteristic that changes in response to dimensional changes of the sensor; and a telemetry device that interrogates the transducer transdermally to measure the changes in the electrical characteristic of the circuit as the concentration of analyte changes.
Claim 3
Dependent Claim
37 words
The sensor system as recited in claim 1 , wherein the circuit comprises at least one mechanically actuated circuit component, wherein the dimensional changes of the sensor are used to mechanically actuate changes in the circuit component.
Claim 4
Dependent Claim
17 words
The sensor system as recited in claim 2 , wherein the circuit component comprises a variable capacitor.
Claim 5
Dependent Claim
33 words
The sensor system as recited in claim 3 , wherein the capacitor comprises two plates, wherein at least one plate moves relative to the other in response to the sensor changing its dimensions.
Claim 6
Dependent Claim
34 words
The sensor system as recited in claim 4 , wherein the transducer further comprises an area that moves in response to the sensor changing dimensions and that is connected to at least one plate.
Claim 7
Dependent Claim
44 words
The sensor system as recited in claim 1 , wherein the transducer further comprises a housing for the sensor, including an area that moves in response to the sensor changing dimensions, and including a rigid, analyte-permeable material that constrains the sensor in the housing.
Claim 8
Dependent Claim
19 words
The sensor system as recited in claim 6 , wherein the area that moves is a pleated, expansible area.
Claim 9
Dependent Claim
43 words
The sensor system as recited in claim 3 , wherein the capacitor comprises two fixed plates and a movable dielectric, wherein changes in dimensions of the sensor cause relative motion of the dielectric and the plates, whereby the capacitance of the capacitor changes.
Claim 10
Dependent Claim
17 words
The sensor system as recited in claim 2 , wherein the circuit component comprises a variable inductor.
Claim 11
Dependent Claim
29 words
The sensor system as recited in claim 9 , wherein the inductor comprises an inductance coil, and the coil's inductance changes in response to the sensor changing its dimensions.
Claim 12
Dependent Claim
24 words
The sensor system as recited in claim 10 , further comprising a magnetic material that moves in response to the sensor changing its dimensions.
Claim 13
Dependent Claim
48 words
The sensor system as recited in claim 9 , wherein the inductor comprises an inductance coil and a magnetic material, wherein at least one of the coil and magnetic material move relative to the other, and the coil's inductance changes in response to the sensor changing its dimensions.
Claim 14
Dependent Claim
29 words
The sensor system as recited in claim 1 , wherein the sensor comprises a polymer capable of reversibly expanding and contracting in volume in the presence of the analyte.
Claim 15
Dependent Claim
23 words
The sensor system as recited in claim 1 , wherein the sensor comprises a hydrogel that changes dimensions in the presence of glucose.
Claim 16
Dependent Claim
42 words
The sensor system as recited in claim 1 , wherein the sensor responds to at least one analyte selected from the group consisting of sugars, urea, ammonia, hydrogen ions, alkaline earth ions, alkali metal ions, transition metal ions, enzymes, and narcotic substances.
Claim 17
Dependent Claim
20 words
The sensor system as recited in claim 2 , wherein the circuit component comprises a micro electromechanical system (MEMS) device.
Claim 18
Dependent Claim
46 words
The sensor system as recited in claim 16 , wherein the MEMS device comprises a cavity into which the sensor is situated, and a flexible conductive membrane covering a portion of the cavity such that the membrane moves in response to the sensor changing its dimensions.
Claim 19
Dependent Claim
42 words
The sensor system as recited in claim 17 , wherein the transducer includes a planar conductive material, wherein the planar material and the membrane comprise plates of a capacitor, wherein the capacitor's capacitance changes in response to the sensor changing its dimensions.
Claim 20
Dependent Claim
23 words
The sensor system as recited in claim 18 , wherein the planar conductive material is deposited on a surface of an etchable substrate.
Claim 21
Dependent Claim
27 words
The sensor system as recited in claim 19 , wherein a well is formed on the surface of the substrate, and the conductive material is deposited thereon.
Claim 22
Dependent Claim
36 words
The sensor system as recited in claim 17 , wherein the MEMS device comprises at least one variable circuit component comprising a variable capacitor, the capacitance of which varies in response to deflections of the membrane.
Claim 23
Dependent Claim
18 words
The sensor system as recited in claim 21 , wherein the MEMS device further comprises an integrated inductor.
Claim 24
Dependent Claim
40 words
The sensor system as recited in claim 17 , wherein the MEMS device comprises at least one variable circuit component comprising a variable inductor, wherein the inductor comprises an inductor coil and a magnetic material that moves with the membrane.
Claim 25
Dependent Claim
39 words
The sensor system as recited in claim 1 , wherein the circuit comprises a micro electromechanical system (MEMS) device which further comprises at least one variable circuit component co-fabricated with other circuit elements to form an integrated MEMS assembly.
Claim 26
Dependent Claim
20 words
The sensor system as recited in claim 1 , wherein telemetry device measures the resonant frequency of the transducer circuit.
Claim 27
Dependent Claim
26 words
The sensor system as recited in claim 1 , wherein telemetry device measures an acoustic tone, the frequency of which is moderated by the transducer circuit.
Claim 28
Independent Claim
100 words
A method for measuring the concentration of an analyte of interest using an implantable sensor system, comprising: providing a transducer, comprising an electronic circuit and a sensor, wherein the sensor comprises a material that selectively responds to an analyte of interest by changing its dimensions, and wherein the circuit has at least one variable electrical characteristic that changes in response to dimensional changes of the sensor; implanting the transducer subcutaneously into a patient; and providing a telemetry device that interrogates the transducer transdermally to measure the changes in the electrical characteristic of the circuit as the concentration of analyte changes.
Claim 29
Independent Claim
100 words
A method for measuring the concentration of an analyte of interest using an implantable sensor system, comprising: providing a transducer, comprising an electronic circuit and a sensor, wherein the sensor comprises a material that selectively responds to an analyte of interest by changing its dimensions, and wherein the circuit has at least one variable electrical characteristic that changes in response to dimensional changes of the sensor; implanting the transducer subcutaneously into a patient; and providing a telemetry device that interrogates the transducer transdermally to measure the changes in the electrical characteristic of the circuit as the concentration of analyte changes.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-03-12 | 2004-09-11 | 2005-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-03-12 | 2008-09-11 | 2009-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-03-12 | 2012-09-11 | 2013-03-13 | $7700.00 | Window Closed / Lapsed |