Implantable ocular glucose sensor devices and methods
Monitoring glucose concentration in aqueous humor can include inserting an implantable device into an eye and determining glucose concentration as a function of glucose sensed at the implantable device. In some implantable device embodiments, the device includes a polymer layer comprising a material that changes volume in response to varying glucose concentrations of the aqueous humor. A pressure sensor in the device can detect the changes in volume. In some implantable device embodiments, the device includes electrodes for determining the glucose concentration.
1. An implantable ocular glucose sensor device, comprising:
a biocompatible housing comprising: (i) a proximal end having a crossbar tab, (ii) a distal end that houses a sensor, and (iii) two or more pairs of lateral protrusions positioned between the proximal and distal ends,
wherein the crossbar tab comprises a first rigid member and a second rigid member, wherein the first and second rigid members extend in opposite lateral directions, wherein the first and second rigid members each include a curved distal surface,
the biocompatible housing configured to be implanted in an incision of a sclera of an eye such that: (i) the crossbar tab protrudes externally of the sclera, (ii) the curved distal surfaces of the first and second rigid members contact and conform with a curvature of the sclera, (iii) the two or more pairs of lateral protrusions are within the sclera to anchor the biocompatible housing to the sclera, and (iv) the sensor is at least partially in an anterior chamber of the eye;
the sensor for measuring a concentration of glucose in aqueous humor of the eye, the sensor disposed at least partially within an interior space defined by the biocompatible housing; and
communication circuitry comprising an antenna or an inductor for wirelessly communicating measured glucose concentrations of the aqueous humor to an external device, the communication circuitry in electrical communication with the sensor and disposed at least partially within the interior space defined by the biocompatible housing, wherein at least a portion of the antenna or the inductor extends into the crossbar tab.
2. The device of claim 1 , wherein the biocompatible housing is thermoplastic polyurethane film.
3. The device of claim 1 , wherein the biocompatible housing is injection molded over the sensor and communication circuitry.
4. The device of claim 1 , wherein the sensor comprises a three-electrode electrochemical system that includes a working electrode, a counter electrode, and a reference electrode.
5. The device of claim 4 , wherein the working electrode is modified with glucose oxidase.
6. The device of claim 4 , wherein the working electrode is modified with glucose dehydrogenase.
7. The device of claim 4 , wherein the working electrode contains a nanostructured metal-oxide layer.
8. The device of claim 1 , wherein the sensor comprises a two-electrode electrochemical system including a working electrode and a dual counter or reference electrode.
9. The device of claim 8 , wherein the working electrode is modified with glucose oxidase.
10. The device of claim 8 , wherein the working electrode is modified with glucose dehydrogenase.
11. The device of claim 8 , wherein the working electrode contains a nanostructured metal-oxide layer.
12. The device of claim 1 , wherein the communication circuitry comprises the inductor.
13. The device of claim 12 , wherein the inductor is connected to a rectifier and used to power the sensor.
14. The device of claim 1 , wherein the communication circuitry comprises an RF antenna.
15. The device of claim 1 , wherein the sensor is powered by a thin film battery disposed within the biocompatible housing.
16. An implantable ocular glucose sensor device, comprising:
a biocompatible housing comprising: (i) a proximal end having a crossbar tab, (ii) a distal end having a polymer layer, and (iii) two or more pairs of lateral protrusions positioned between the proximal and distal ends,
wherein the crossbar tab comprises a first rigid member and a second rigid member, wherein the first and second rigid members extend in opposite lateral directions, wherein the first and second rigid members each include a curved distal surface,
the biocompatible housing configured to be implanted in an incision of a sclera of an eye such that: (i) the crossbar tab protrudes externally of the sclera, (ii) the curved distal surfaces of the first and second rigid members contact and conform with a curvature of the sclera, (iii) the two or more pairs of lateral protrusions are within the sclera to anchor the biocompatible housing to the sclera, and (iv) the sensor is at least partially in an anterior chamber of the eye;
the polymer layer disposed at least partially within an interior space defined by the biocompatible housing, at least a portion of the polymer layer exposed to aqueous humor of the eye while the device is implanted in the eye, the polymer layer comprising a material that changes volume in response to varying glucose concentrations of the aqueous humor;
a pressure sensor disposed at least partially within the interior space defined by the biocompatible housing and abutting the polymer layer; and
communication circuitry comprising an antenna or an inductor for wirelessly communicating pressure signals from the pressure sensor to an external device, the communication circuitry in electrical communication with the pressure sensor and disposed at least partially within the interior space defined by the biocompatible housing, wherein at least a portion of the antenna or the inductor extends into the crossbar tab.
17. The device of claim 16 , wherein the polymer layer comprises boronic acid or a boronic acid derivative.
18. The device of claim 16 , wherein the polymer layer is covered by a glucose permeable membrane.
19. The device of claim 16 , wherein the communication circuitry comprises the inductor.
20. The device of claim 19 , wherein the inductor forms a passive LC resonator with the pressure sensor.
21. The device of claim 20 , wherein the passive LC resonator transmits glucose concentration to an external antenna through a change in resonant frequency of the passive LC resonator.