IC-processed microneedles

• US 5,591,139 A
• Filed: 06/06/1994
• Issued: 01/07/1997
• Est. Priority Date: 06/06/1994
• Status: Expired due to Term

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Pisano, Albert P., Lin, Liwei
• Primary Examiner(s): MENDEZ, MANUEL A
• Application Number:
  US08/254,328
• Time in Patent Office: 946 Days
• Field of Search: 604/22, 604/264, 604/280, 604/30, 604/43, 604/51-53
• US Class Current: 604/264
• CPC Class Codes: A61B 17/205 Vaccinating by means of needles or other puncturing devices
• CPC Class Codes: A61M 37/00 Other apparatus for introducing media into the body for reproduction or fertilisation A61B17/425; apparatus for iontophoresis or cataphoresis A61N1/30; Percutany, i.e. introducing medicines into the body by diffusion through the skin salt baths A61H33/04
• CPC Class Codes: A61M 37/0015 by using microneedles
• CPC Class Codes: G01N 2035/00237 Handling microquantities of analyte, e.g. microvalves, capillary networks
• CPC Class Codes: G01N 33/4833 of solid biological material, e.g. tissue samples, cell cultures tissue in vivo A61B5/00; cell suspensions G01N33/48735

Abstract

An IC-processed microneedle including an interface region and shaft. A shell defines an enclosed channel to form the shaft. The shaft has ports to permit fluid movement therethrough. Microheaters, microdetectors and additional devices may also be fabricated on the microneedle.

Claims

1. A microstructure, comprising:

a substrate having an interface region and an elongated region extending from said interface region; and

a shell connected with said substrate along said elongated region and at least a portion of said interface region;

wherein said substrate and shell define a shaft having an enclosed channel.

2. The microstructure of claim 1 further including:

a plurality of shells connected with said substrate along said elongated region and at least a portion of said interface region;

wherein said substrate and shells define a plurality of enclosed channels.

3. The microstructure of claim 1 wherein said channel has a width of between about 30 and 60 micrometers, and a height of about 9 micrometers or less.

4. The microstructure of claim 1 wherein:

said shaft includes a first end at said interface region, a second end distal from said first end, and at least two ports for permitting movement of a fluid therethrough.

5. The microstructure of claim 4 further including:

heating means at said first end of said shaft for heating a liquid within said shaft, whereby said liquid forms a bubble and moves within said shaft.

6. The microstructure of claim 5 wherein said heating means comprises a polysilicon resistor.

7. The microstructure of claim 4 further including:

detecting means on said elongated portion for monitoring electrical activity generated by biological tissue in which said microstructure is inserted.

8. The microstructure of claim 7 wherein said detecting means is located at said second end of said shaft.

9. The microstructure of claim 7 wherein said detecting means includes:

a polysilicon resistor.

10. The microstructure of claim 8 wherein said distal end is of dimensions suitable to be inserted between adjacent cells of biological tissue.

11. The microstructure of claim 10 further including a chemical contained in said channel, wherein the chemical is delivered to biological tissue through said channel, and said detector means records the response of the biological tissue to the chemical, providing a real-time measurement of the biological tissue, when the distal end is inserted into biological tissue.

12. The microstructure of claim 8 further including a detector electrode extending from said detector means to said interface region.

13. The microstructure of claim 12 wherein said detector electrode extends through said channel.

14. The microstructure of claim 4 further including fluid movement means for moving a fluid along said shaft.

15. The microstructure of claim 14 wherein said fluid movement means includes:

a plurality of resistors fabricated proximate each other, wherein when said resistors are heated in sequence, a vapor bubble produced is moved sequentially along said resistors.

16. The microstructure of claim 15 wherein said plurality of resistors are positioned in a line.

17. The microstructure of claim 4 wherein a first of said at least two ports is located at said first end of said shaft and a second of said at least two ports is located at said second end of said shaft.

18. The microstructure of claim 4 further including electronic components fabricated on said interface region.

19. The microstructure of claim 18 wherein said components are CMOS devices.

20. The microstructure of claim 4 further including a plurality of end channels converging at said first end and communicating with said enclosed channel.

21. The microstructure of claim 4 wherein its elements are formed by integrated-circuit microfabrication methods.

22. The microstructure of claim 4 wherein said interface region has an area of about 2 to 3 millimeters square, said elongated region has a length of between about 1 to 6 millimeters, and said shaft has a height of about 70 micrometers.

23. The microstructure of claim 4 further comprising a blood analysis amplifier and A/D converter positioned on said interface region, said A/D converter connected to said blood analysis amplifier, wherein blood is draw into said channel and communicated to said blood analysis amplifier, and real-time blood information is transmitted to an external source via the A/D converter when said distal end is inserted into a blood vessel.

24. An microneedle, comprising:

an interface region having an area of 2 to 3 millimeters square; and

an elongated hollow shaft connected to and extending from said interface region for permitting movement of a fluid therethrough, said shaft having a length of between about 1 and 6 millimeters, said shaft having at a distal end width of about 50 micrometers or less and a height of about 9 micrometers or less.

25. The microneedle of claim 24 further including at least one resistor located within said shaft for heating a fluid to form a bubble that moves along said shaft.

26. A microstructure fabricated by a process comprising the steps of:

providing a substrate for forming an interface region and an elongated portion extending away from said interface region, said substrate including a frontside and a backside;

forming a patterned, non-planar etchable structure on the frontside of said elongated portion;

depositing an unetchable membrane layer atop said etchable structure;

opening at least one etching hole in said membrane layer; and

etching said etchable structure by placing an etchant into said etching hole, said etchable structure being etched to a predetermined extent to form a cavity underneath said membrane layer, thereby producing a shaft formed from said membrane layer and said elongated portion of said substrate.