Microneedle arrays and methods of manufacturing the same

• US 20030045837A1
• Filed: 09/05/2001
• Published: 03/06/2003
• Est. Priority Date: 09/05/2001
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Huntley, Douglas A., Fleming, Patrick R., Thomas, Cristina U., Keister, Jamieson C., Delmore, Michael D., Ferber, Richard H.
• Granted Patent: US 6,881,203 B2
• Time in Patent Office: Days
• US Class Current: 604/173
• CPC Class Codes: A61B 2562/0295 Strip shaped analyte sensors for apparatus classified in A61B5/145 or A61B5/157
• CPC Class Codes: A61B 5/14514 using means for aiding extraction of interstitial fluid, e.g. microneedles or suction
• CPC Class Codes: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/150099 by negative pressure, other than vacuum extraction into a syringe by pulling on the piston rod or into pre-evacuated tubes
• CPC Class Codes: A61B 5/150229 Pumps for assisting the blood sampling
• CPC Class Codes: A61B 5/150282 for piercing elements, e.g. blade, lancet, canula, needle
• CPC Class Codes: A61B 5/150358 Strips for collecting blood, e.g. absorbent optical reagent test strips G01N21/8483; chemical reagent test strips G01N33/4875, G01N33/52
• CPC Class Codes: A61B 5/150969 Low-profile devices which resemble patches or plasters, e.g. also allowing collection of blood samples for testing
• CPC Class Codes: A61B 5/150984 Microneedles or microblades
• CPC Class Codes: A61M 2037/0007 having means for enhancing the permeation of substances through the epidermis, e.g. using suction or depression, electric or magnetic fields, sound waves or chemical agents
• CPC Class Codes: A61M 2037/003 having a lumen
• CPC Class Codes: A61M 2037/0038 having a channel at the side surface
• CPC Class Codes: A61M 2037/0053 Methods for producing microneedles
• CPC Class Codes: A61M 37/0015 by using microneedles

Abstract

Microneedle arrays, methods of manufacturing microneedles and methods of using microneedle arrays. The microneedles in the microneedle arrays may be in the form of tapered structures that include at least one channel formed in the outside surface of each microneedle. The microneedles may have bases that are elongated in one direction. The channels in microneedles with elongated bases may extend from one of the ends of the elongated bases towards the tips of the microneedles. The channels formed along the sides of the microneedles may optionally be terminated short of the tips of the microneedles. The microneedle arrays may also include conduit structures formed on the surface of the substrate on which the microneedle array is located. The channels in the microneedles may be in fluid communication with the conduit structures. One manner of using microneedle arrays of the present invention is in methods involving the penetration of skin to deliver medicaments or other substances and/or extract blood or tissue.

Claims

1. A microneedle array device comprising:

a plurality of microneedles projecting from a substrate surface, wherein each of the microneedles comprises a tapered shape comprising an outer surface, a base proximate the substrate surface, and a tip distal from the base, and further wherein the base is elongated along an elongation axis on the substrate surface such that the base comprises opposing ends along the elongation axis; and

a channel formed in the outer surface of each microneedle of the plurality of microneedles, each channel extending from the base towards the tip of the microneedle.

2. A device according to claim 1, wherein the channel extends from one of the opposing ends of the elongated base towards the tip of the microneedle.

3. A device according to claim 1, wherein the channel extends from an intermediate location between the opposing ends of the elongated base towards the tip of the microneedle.

4. A device according to claim 1, wherein the channel terminates short of the tip of the microneedle.

5. A device according to claim 1, wherein the channel in each of the microneedles extends to the tip of the microneedle.

6. A device according to claim 1, wherein the base comprises an oval.

7. A device according to claim 1, wherein the channel comprises a channel depth, and further wherein the channel depth at the base of the microneedle is less than half of the dimension of the base as measured between the opposing ends.

8. A device according to claim 1, wherein the elongation axes of the plurality of microneedles are aligned with each other on the substrate surface.

9. A device according to claim 1, further comprising a conduit structure formed on the substrate surface, the channel in each microneedle of the plurality of microneedles is in fluid communication with the conduit structure on the substrate surface.

10. A device according to claim 9, wherein the conduit structure comprises a series of barriers projecting from the substrate surface, with fluid pathways of the conduit structure being defined by the barriers.

11. A microneedle array device comprising:

a plurality of microneedles projecting from a substrate surface, wherein each of the microneedles comprises a tapered shape comprising an outer surface, a base proximate the substrate surface and a tip distal from the base; and

a channel formed in the outer surface of each microneedle of the plurality of microneedles, each channel extending from the base of the microneedle towards the tip of the microneedle, wherein the channel terminates short of the tip of the microneedle.

12. A device according to claim 11, wherein, for each microneedle of the plurality of microneedles, the base of the microneedle is elongated along an elongation axis on the substrate surface such that the base comprises opposing ends along the elongation axis, and wherein the channel extends from one of the opposing ends of the elongated base towards the tip of the microneedle.

13. A device according to claim 12, wherein the elongation axes of the plurality of microneedles are aligned with each other on the substrate surface.

14. A device according to claim 11, wherein, for each microneedle of the plurality of microneedles, the base of the microneedle is elongated along an elongation axis on the substrate surface such that the base comprises opposing ends along the elongation axis, and wherein the channel extends from an intermediate location between the opposing ends of the elongated base towards the tip of the microneedle.

15. A device according to claim 14, wherein the elongation axes of the plurality of microneedles are aligned with each other on the substrate surface.

16. A device according to claim 11, wherein the base comprises an oval.

17. A device according to claim 11, wherein the channel comprises a channel depth, and further wherein the channel depth at the base of the microneedle is less than half of a maximum dimension of the base on the substrate surface.

18. A device according to claim 11, further comprising a conduit structure formed on the substrate surface, the channel in each microneedle of the plurality of microneedles is in fluid communication with the conduit structure on the substrate surface.

19. A device according to claim 18, wherein the conduit structure comprises a series of barriers projecting from the substrate surface, with fluid pathways of the conduit structure being defined by the barriers.

20. A method of delivering a microneedle array to a skin impact site, the method comprising:

positioning a microneedle array proximate a delivery site, the microneedle array comprising a plurality of microneedles protruding from a surface;

applying an impact force to the microneedle array over a period of less than about 1 second, wherein the plurality of microneedles are driven through the stratum corneum at the skin impact site.

21. A method according to claim 20, wherein the period is less than about 500 milliseconds.

22. A method according to claim 20, wherein the period is less than about 300 milliseconds.

23. A method according to claim 20, wherein applying the impact force to the microneedles array comprises accelerating the microneedle array towards the skin impact site.

24. A method according to claim 20, wherein the microneedle array is in contact with the skin impact site before applying the impact force to the microneedle array.

25. A method according to claim 20, further comprising removing the microneedle array from contact with the skin impact site within about 1 second after the plurality of microneedles are driven through the stratum corneum at the skin impact site.

26. A method according to claim 20, further comprising retaining the microneedle array in contact with the skin impact site for about 2 seconds or more after the plurality of microneedles are driven through the stratum corneum at the skin impact site.

27. A method according to claim 20, wherein the impact force has a maximum of about 40 N/cm² or less.

28. A method according to claim 20, wherein the impact force has a maximum of about 20 N/cm² or less.

29. A method according to claim 20, further comprising drawing a vacuum at the skin impact site after the plurality of microneedles are driven through the stratum corneum at the skin impact site.

30. A method according to claim 20, further comprising locating an indicator in contact with the skin impact site after the plurality of microneedles are driven through the stratum corneum at the skin impact site.

31. A method according to claim 20, wherein the method further comprises:

locating an indicator in contact with the skin impact site after the plurality of microneedles are driven through the stratum corneum at the skin impact site; and

drawing a vacuum at the skin impact site after the plurality of microneedles are driven through the stratum corneum at the skin impact site.

32. A microneedle array delivery device comprising:

a microneedle array comprising a plurality of microneedles protruding from a surface;

a driver operably connected to the microneedle array, wherein the driver comprises stored energy;

wherein release of the stored energy results in application of an impact force to the microneedle array over a period of less than about 1 second.

33. A device according to claim 32, wherein the driver comprises at least one mechanical spring.

34. A method according to claim 32, wherein the driver comprises at least one resilient member.

35. A method according to claim 32, wherein the driver comprises a compressed fluid.