Flexible electrode for brain and method for manufacturing same
The present disclosure relates to a flexible electrode for a brain and a method for manufacturing the same. Provided is a flexible electrode for the brain, which comprises a cortical attachment portion that can be implanted into the brain, and one or more deep implantation portions, the cortical attachment portion having a sheet-like structure capable of covering and being flattened to fit against at least a portion of a cerebral cortex after implantation, and the deep implantation portions being configured to be implanted into a deep region of the brain and bent relative to the cortical attachment portion after implantation, wherein the deep implantation portions and the cortical attachment portion each comprise one or more electrode sites, each of the electrode sites being electrically coupled to one of wires in the wire layer and being in contact with the brain after the flexible electrode is implanted into the brain.
1 . A flexible electrode for a brain, comprising:
a cortical attachment portion capable of being implanted into the brain; and
one or more deep implantation portions;
wherein the cortical attachment portion has a sheet-like structure capable of covering and being flattened to fit against at least a portion of a cerebral cortex after an implantation;
wherein the one or more deep implantation portions being configured to be implanted into a deep region of the brain and bent relative to the cortical attachment portion after the implantation;
wherein the flexible electrode comprises:
a first insulating layer,
a second insulating layer, and
a wire layer located between the first insulating layer and the second insulating layer; and
wherein at least one of the one or more deep implantation portions and the cortical attachment portion, each comprises one or more electrode sites, each of which is electrically coupled to at least one wire in the wire layer and in contact with the brain after the flexible electrode is implanted into the brain, to acquire, from the brain, at least one first electrical signal and transmit the at least one first acquired electrical signal by the at least one wire, or apply, to the brain, at least one second electrical signal received by the at least one wire;
wherein the wire layer comprises a conductive sub-layer;
wherein a material of the conductive sub-layer is any one of gold, platinum, iridium, tungsten, platinum iridium alloy, titanium alloy, graphite, carbon nanotube, PEDOT, or any combination thereof; and
wherein the conductive sub-layer has a thickness of 5 nanometers to 200 micrometers, or, when neither at least one electrode site nor at least one backend site is located in the wire layer, the wire layer further comprises an adhesion sub-layer close to either the at least one electrode site or the at least one backend site, and a material of the adhesion sub-layer is any one of chromium, tantalum, tantalum nitride, titanium, titanium nitride, or any combination thereof.
2 . The flexible electrode according to claim 1 , wherein at least one deep implantation portion of the one or more deep implantation portions extends from the cortical attachment portion, and has at least one mounting through-hole, through which an electrode implantation device is attached to the at least one deep implantation portion for the implantation of the at least one deep implantation portion.
3 . The flexible electrode according to claim 1 , wherein, the flexible electrode comprises a plurality of wire layers which are spaced apart by an additional insulating layer, and each of the wire layers comprises therein a plurality of wires spaced apart from each other.
4 . The flexible electrode according to claim 1 , wherein, the flexible electrode is configured to be implanted into the brain using a support bracket.
5 . The flexible electrode according to claim 4 , wherein, the support bracket has a micromechanical mechanism, comprising a cantilever beam, a latch, or a linkage mechanism.
6 . The flexible electrode according to claim 4 , wherein, the support bracket is configured to implant the flexible electrode by microfluidics.
7 . The flexible electrode according to claim 4 , wherein, a material of the support bracket is any one of tungsten, platinum, titanium, magnesium, polyimide, polydimethylsiloxane, hydrogel, epoxy, polyethylene, chitosan, polyethylene glycol, or any combination thereof.
8 . The flexible electrode according to claim 4 , wherein, the support bracket is configured to implant the cortical attachment portion and the at least one deep implantation portion of the flexible electrode into a portion of the brain that is not easily accessible by craniotomy, the portion being located at one or more of a frontal lobe, occipital lobe, temporal lobe, or central cerebral great vessel.
9 . The flexible electrode according to claim 4 , wherein, the support bracket is configured to implant the flexible electrode along a gap between the brain and a skull.
10 . The flexible electrode according to claim 1 , wherein the flexible electrode is configured to remain in a flattened, rolled, or wrapped state during the implantation, and is capable of being removed from the brain in the flattened, rolled, or wrapped state.
11 . The flexible electrode according to claim 1 , wherein, at least one electrode site of the one or more electrode sites is located in the wire layer and exposed through at least one via hole in at least one of the first insulating layer or the second insulating layer.
12 . The flexible electrode according to claim 1 , wherein
at least one electrode site of the one or more electrode sites is located on an outer side of at least one of the first insulating layer or the second insulating layer, and electrically coupled to a wire in the wire layer through at least one via hole in the at least one layer.
13 . The flexible electrode according to claim 12 , wherein, the at least one electrode site comprises a conductive sub-layer, and a material of the conductive sub-layer is any one of gold, platinum, iridium, tungsten, magnesium, molybdenum, platinum iridium alloy, titanium alloy, graphite, carbon nanotube, PEDOT, or any combination thereof.
14 . The flexible electrode according to claim 13 , wherein, the at least one electrode site further comprises an adhesion sub-layer close to the wire layer, the adhesion sub-layer being made of a material capable of enhancing adhesion between the electrode site and the wire layer.
15 . The flexible electrode according to claim 1 , wherein a maximum side length or diameter of the one or more electrode sites is 1 micrometer to 500 micrometers, and a spacing between the one or more electrode sites is 10 micrometers to 10 millimeters therebetween.
16 . The flexible electrode according to claim 15 , wherein, at least one first electrode site of the at least one deep implantation portion has a smaller size than at least one second electrode site of the cortical attachment portion.
17 . The flexible electrode according to claim 16 , wherein, the at least one first electrode site of the at least one deep implantation portion has a maximum side length or diameter of 1 micrometer to 2 millimeters, and the at least one second electrode site of the cortical attachment portion has a maximum side length or diameter of 1 micrometer to 500 millimeters.
18 . The flexible electrode according to claim 1 , wherein, a surface of at least one electrode site of the one or more electrode sites that is in contact with a biological tissue has a surface modification layer that is configured to improve an electrochemical property of the at least one electrode site.
19 . The flexible electrode according to claim 18 , wherein, surface modification is performed by using any one or more of a conductive polymer and a conductive metal particle, the conductive polymer comprising Polydioxyethylthiophene, Poly (styrene sulfonate), polypyrrole, and a material of the conductive metal particle comprising iridium, iridium oxide, platinum, and platinum iridium alloy.
20 . The flexible electrode according to claim 1 , further comprising one or more backend portions extending from the cortical attachment portion, wherein
at least one backend portion of the one or more backend portions comprises a backend site, which is coupled to one of the wires in the wire layer and a backend circuit, to implement bidirectional signal transmission between the electrode site electrically coupled to the one of the wires and the backend circuit.
21 . The flexible electrode according to claim 20 , wherein, the backend site is located in the wire layer and exposed through a through-hole in at least one of the first insulating layer or the second insulating layer.
22 . The flexible electrode according to claim 20 , wherein, the backend site is located between at least one of the first insulating layer or the second insulating layer and the wire layer, and exposed through a through-hole in the other of the first insulating layer and the second insulating layer.
23 . The flexible electrode according to claim 22 , wherein, the backend site comprises a conductive sub-layer, and a material of the conductive sub-layer is any one of gold, platinum, iridium, tungsten, magnesium, molybdenum, platinum iridium alloy, titanium alloy, graphite, carbon nanotube, PEDOT, or any combination thereof; or
the backend site comprises an adhesion sub-layer close to the wire layer, and a material of the adhesion sub-layer being is any one of chromium, tantalum, tantalum nitride, titanium, and titanium nitride, or any combination thereof, or
the backend site has a thickness of 5 nanometers to 200 micrometers.
24 . The flexible electrode according to claim 1 , wherein, the first insulating layer and the second insulating layer have a thickness of 100 nanometers to 300 micrometers, or
a material of the first insulating layer and the second insulating layer is any one of polyimide, polydimethylsiloxane, parylene, epoxy, polyamide imide, SU-8 photoresist, silica gel, silicone rubber, or any combination thereof.
25 . The flexible electrode according to claim 1 , further comprising a flexible separation layer, wherein, the flexible separation layer is capable of being removed by a specific substance to separate a part of the flexible electrode without damage to the flexible electrode.
26 . The flexible electrode according to claim 25 , wherein, a material of the flexible separation layer is any one of nickel, chromium, and aluminum, or any combination thereof, or the flexible separation layer further comprises an adhesion sub-layer, and a material of the adhesion sub-layer is chromium, tantalum, tantalum nitride, titanium, or titanium nitride.
27 . The flexible electrode according to claim 1 , wherein, a material of the wire layer is any one of magnesium, molybdenum, molybdenum alloy, or any combination thereof, and a material of the first insulating layer and the second insulating layer is any one of polylactic acid, or polylactic acid-glycolic acid copolymer, or any combination thereof, so that the flexible electrode is biodegradable.
28 . A method for manufacturing a flexible electrode for a brain, the flexible electrode being the flexible electrode according to claim 25 , the method comprising:
manufacturing, on a substrate, the first insulating layer, the wire layer, the second insulating layer, and the electrode site; and
separating the flexible electrode from the substrate,
wherein the at least one via hole is manufactured by patterning, at a position of at least one of the first insulating layer or the second insulating layer that corresponds to the at least one electrode site.