MEMS device and method for delivery of therapeutic agents
Embodiments of an implantable device for delivering a therapeutic agent to a patient include a reservoir configured to contain a liquid comprising the therapeutic agent, and a cannula in fluid communication with the reservoir. The cannula is shaped to facilitate insertion thereof into a patient's eyeball.
1. An implantable electrolytic pump comprising:
a first exterior surface shaped to fit on the curved contour of an eyeball;
a drug chamber for containing a liquid to be administered;
a refill port resealably puncturable by a needle to facilitate refilling of the drug chamber;
a cannula in fluid communication with the chamber, an end of the cannula being shaped to facilitate insertion thereof into the eyeball;
first and second electrodes; and
a membrane disposed above the electrodes, the membrane being configured to expand and contract with increases and decreases in pressure, activation of the electrodes causing creation of a gas within the chamber to thereby expand the membrane so that liquid is forced from the chamber into the cannula, wherein (i) the first electrode includes at least one central elongate portion and a plurality of elongations extending from the at least one central elongate portion, and (ii) the second electrode at least partially encircles the first electrode.
2. The pump of claim 1 wherein the electrodes and the membrane are contained within the chamber.
3. The pump of claim 1 further comprising a separate electrolysis chamber, adjacent to the drug chamber, for containing a working fluid sealed therein, the electrodes being disposed in the electrolysis chamber.
4. The pump of claim 1 wherein the end of the cannula is tapered.
5. The pump of claim 1 wherein the end of the cannula has rounded corners.
6. The pump of claim 1 wherein the cannula comprises a flow regulator.
7. The pump of claim 6 wherein the flow regulator comprises a valve.
8. The pump of claim 1 wherein the first and second electrodes are co-planar.
9. The pump of claim 1 wherein the membrane comprises parylene.
10. The pump of claim 1 wherein the first electrode and the second electrode are both planar.
11. The pump of claim 10 wherein the first electrode and the second electrode are interdigitated with one another.
12. A method of delivering a therapeutic agent to a patient, the method comprising:
providing a pump comprising (i) an exterior surface shaped to fit on the curved contour of an eyeball, (ii) a drug chamber containing a liquid to be administered, (iii) a cannula in fluid communication with the chamber, an end of the cannula being shaped to facilitate insertion thereof into the eyeball, (iv) first and second electrodes, (v) a flexible, corrugated membrane disposed above the electrodes, and (vi) a generally circular wall disposed between the first and second electrodes, the generally circular wall including at least one fluid passageway;
placing the pump on the patient's eyeball;
inserting the end of the cannula into the eyeball; and
energizing the electrodes to cause creation of a gas within the chamber to thereby expand the membrane so that liquid is forced from the chamber through the cannula and is administered to the patient's eye,
wherein (i) the first electrode includes at least one central elongate portion and a plurality of elongations extending from the at least one central elongate portion, and (ii) the second electrode at least partially encircles the first electrode.
13. The method of claim 12 wherein the electrodes and the membrane are contained within the chamber.
14. The method of claim 12 wherein the pump comprises a separate electrolysis chamber adjacent to the drug chamber and the electrodes are disposed in the electrolysis chamber, and further comprising the step of providing a working fluid in the electrolysis chamber, the step of energizing the electrodes causing the gas to be created within the electrolysis chamber.
15. The method of claim 12 wherein the end of the cannula is tapered.
16. The method of claim 12 wherein the end of the cannula has rounded corners.
17. The method of claim 12 further comprising the step of regulating fluid flow through the cannula.
18. The method of claim 17 wherein the flow regulator comprises a valve.
19. The method of claim 12 further comprising the step of refilling the pump through a refill port in fluid communication with the drug chamber.
20. The method of claim 12 wherein the membrane comprises parylene.
21. The method of claim 12 wherein the pump further comprises a battery for operating the circuitry, and further comprising the step of wirelessly charging the battery.
22. The pump of claim 1 , further comprising a liquid-permeable barrier disposed between the first and second electrodes.
23. The pump of claim 22 , wherein the liquid-permeable barrier comprises a wall with at least one fluid passageway therethrough.
24. The pump of claim 22 , wherein the liquid-permeable barrier is gas-impermeable.