3D microelectrode device for live tissue applications

Patent metadata

Field	Value
Publication number	US-9248273-B2
Application number	US-201313919013-A
Country	US
Kind code	B2
Filing date	Jun 17, 2013
Priority date	Jun 18, 2012
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

A 3D microelectrode device includes a flexible substrate containing poly-dimethyl siloxane (PDMS). The device may be fabricated in a miniature form factor suitable for attachment to a small organ such as a lateral gastrocnemius muscle of a live rat. In addition to providing a miniaturized, conformable attachment, the device provides an anchoring action via one or more microelectrodes, each having an insertable tip particularly shaped to provide the anchoring action. Furthermore, a base portion of each of the microelectrodes is embedded inside conductive poly-dimethyl siloxane (cPDMS). The cPDMS is contained in a pad that is coupled to a conductive track embedded in the flexible substrate. Embedding of the base portion inside the cPDMS material not only allows the microelectrode to bend in various directions, but also provides good electrical conductivity while eliminating the need for attachment processes using solder or epoxy adhesives.

First claim

The invention claimed is:

1. An implantable device comprising:
a flexible substrate configured to provide three-dimensional conformance with a live organ, muscle, or tissue susceptible to movement;
at least one track embedded in the flexible substrate for conducting an electrical signal, the track comprising conductive poly-dimethyl siloxane (cPDMS) material; and
at least one microelectrode comprising a base portion, a longitudinal portion, and an insertable tip, the base portion having a shape configured for anchoring the base portion in the cPDMS material, and the insertable tip having a leading portion configured for penetrating an outer surface of the organ, muscle, or tissue.

2. The device according to claim 1 , wherein the insertable tip has a trailing portion having a shape configured for anchoring the microelectrode to the organ, muscle, or tissue.

3. The device according to claim 2 , wherein the insertable tip is an arrowhead tip located at one end of the longitudinal portion, and the base portion is located at an opposing end of the longitudinal portion.

4. The device according to claim 3 , wherein the trailing portion of the arrowhead tip is configured to be oriented substantially parallel to the outer surface of the organ, muscle, or tissue when the leading portion of the arrowhead tip has penetrated the outer surface of the organ, muscle, or tissue.

5. The device according to claim 3 , wherein the trailing portion of the arrowhead tip is configured to be oriented at an angle to the outer surface of the organ, muscle, or tissue when the leading portion of the arrowhead tip has penetrated the outer surface of the organ, muscle, or tissue, the angle selected to provide a hindering action when the arrowhead tip is withdrawn through the outer surface of the organ, muscle, or tissue.

6. The device according to claim 1 , wherein the microelectrode is a stainless steel microneedle and the flexible substrate comprises poly-dimethyl siloxane (PDMS) material.

7. The device according to claim 6 , wherein the stainless steel microneedle is one of a laser micromachined stainless steel microneedle or a electrochemically-milled stainless steel microneedle having a minimum sharpness that is less than or equal to about 1 μm, and wherein a minimum width of the track is about 1 μm.

8. The device according to claim 6 , wherein the flexible substrate, the track, and the stainless steel microneedle are included in an implantable package configured to be inserted under the tissue surface.

9. The device according to claim 8 , wherein the flexible substrate included in the implantable package is selected for placement of the implantable package on at least one of a kidney or a brain of a rat.

10. The device according to claim 8 , wherein the flexible substrate included in the implantable package is selected for placement of the implantable package on a lateral gastrocnemius muscle of a rat.

11. The device according to claim 6 , wherein the implantable device is configured to interface with a device for containing and testing cells in-vitro.

12. The device according to claim 1 , further comprising:
a plurality of signal-conducting tracks embedded in the flexible substrate, each of the plurality of tracks comprising conductive poly-dimethyl siloxane (cPDMS) material; and
a plurality of microelectrodes arranged in an array configuration, each of the plurality of microelectrodes comprising a base portion and a protruding portion, the base portion having a shape configured for anchoring the microelectrode in the cPDMS material, and the protruding portion having a shape configured for penetrating the outer surface of the organ, muscle, or tissue and for anchoring the implantable device in the organ, muscle, or tissue.

13. The device according to claim 12 , wherein the base portion comprises a substantially planar surface oriented orthogonal to a longitudinal axis of the protruding portion.

14. The device according to claim 13 , wherein the protruding portion comprises a longitudinal shaft having the base portion located at one end and a pointed tip located at an opposing end.

15. The device according to claim 14 , wherein the longitudinal shaft has at least one of a circular, a rectangular, or a square cross-section, and wherein the pointed tip is an arrowhead tip.

16. The device according to claim 15 , wherein the arrowhead tip includes at least one tapered corner for anchoring the arrowhead tip to the organ, muscle, or tissue.

17. The device according to claim 16 , wherein each of the plurality of microelectrodes is one of a laser micromachined stainless steel microneedle or a electrochemically-milled stainless steel microneedle having a minimum sharpness of less than or equal to about 1 μm and wherein the flexible substrate comprises poly-dimethyl siloxane (PDMS) material.

18. The device according to claim 12 , wherein the array configuration is at least a 2×2 array of microelectrodes arranged in an area of about 2 mm 2 , with an inter-electrode spacing of about 200 μm.

Assignees

• Axion Biosystems Inc
• Georgia Inst Technology
• Georgia Tech Res Inst

Inventors

• Guvanasen Gareth S
• Rajaraman Swaminathan
• Aguilar Jr Ricardo
• Guo Liang
• Nichols T Richard
• Deweerth Stephen P

Classifications

• A61B5/24

  Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof · CPC title

• A61N1/0551 Primary

  Spinal or peripheral nerve electrodes · CPC title

• A61B5/0492

  Human Necessities · mapped topic

• A61B2562/0209

  Special features of electrodes classified in A61B5/24, A61B5/25, A61B5/283, A61B5/291, A61B5/296, A61B5/053 · CPC title

• H05K1/0283

  Stretchable printed circuits · CPC title