Implantable electrode assembly based on multiplexing

Abstract

The invention relates to the technical field of brain-computer interfaces, and discloses a multiplexing-based implantable electrode assembly, which comprises a sensing device, a multiplexing device, a packaging piece and a flexible substrate, and is characterized in that the sensing device is in contact with biological brain tissues and is used for acquiring electroencephalogram signals; the electroencephalogram signals acquired by the sensing device are transmitted to the multiplexing device through the packaging part, and the multiplexing device transmits the received electroencephalogram signals to external equipment; the packaging piece comprises at least two layers of organic materials and at least one layer of metal materials; the flexible substrate is used for bearing the multiplexing device. In other words, at least two layers of organic materials are arranged between the sensing device and the multiplexing device and used for preventing cerebrospinal fluid from flowing into the multiplexing device from the sensing device, and at least one layer of metal materials is used for transmitting electroencephalogram signals to the multiplexing device from the sensing device. The three-layer structure prevents cerebrospinal fluid from making contact with a multiplexing device, and electrode damage caused by short circuit of the electrode assembly is avoided.

Description

Technical Field

[0001] This invention belongs to the field of brain-computer interfaces, and in particular relates to an implantable electrode assembly based on multiplexing. Background Technology

[0002] Precise and efficient recording of brain neuronal signals is crucial for advancing neuroscience research and promoting clinical applications. Electrocorticography (ECoG) measures signals from cortical neurons by attaching electrodes directly to the exposed surface of the cerebral cortex, allowing for high spatial resolution acquisition of signals from individual brain regions and large areas, thus enabling a more comprehensive understanding of brain information in a spatial sense.

[0003] Existing ECoG electrode assemblies are placed on the exposed surface of the cerebral cortex. The large amount of cerebrospinal fluid in this area creates a complex intracranial solution environment, in which the electrodes are prone to cerebrospinal fluid infiltration, which can lead to electrode damage. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide an implantable electrode assembly based on multiplexing, the main purpose of which is to prevent cerebrospinal fluid from flowing into the multiplexing device and avoid electrode damage while ensuring high-throughput data transmission of the electrode assembly.

[0005] To achieve the above objectives, the present invention mainly provides the following technical solutions: This invention provides an implantable electrode assembly based on multiplexing, comprising: a sensor, a multiplexing device, a package, and a flexible substrate; the sensor is in contact with biological brain tissue and is used to acquire electroencephalogram (EEG) signals; the multiplexing device is connected to the sensor through the package and is used to transmit the received EEG signals to an external device; wherein, the package comprises at least two layers of organic material and at least one layer of metal material; the flexible substrate is used to support the multiplexing device.

[0006] Optionally, the package includes a first metal layer, a first surface of the first metal layer being attached to a first interface of the multiplexing device, a second surface of the first metal layer being attached to a first interface of the sensor, and the first interface of the multiplexing device and the first interface of the sensor being provided with a preset distance in the horizontal direction.

[0007] Optionally, the preset distance ranges from 10µm to 200mm.

[0008] Optionally, the package further includes a first organic layer and a second organic layer; a third surface of the first metal layer is bonded to the first organic layer, and a fourth surface of the first metal layer is bonded to the second organic layer.

[0009] Optionally, the first metal layer may be in the form of a letter with a zigzag structure.

[0010] Optionally, the first metal layer is T-shaped.

[0011] Optionally, the first region of the multiplexing device is provided with multiple electrode points, and the second region of the multiplexing device is provided with multiple leads; wherein, the first region includes the second region, the multiple electrode points are used to acquire EEG signals, and the multiple leads are used to transmit the EEG signals.

[0012] Optionally, the multiple leads include at least: acquisition leads and control leads; wherein, the acquisition leads are used to transmit the EEG signals to an external device; and the control leads are used to send control signals to the multiplexing device.

[0013] Optionally, the number of acquisition leads is m, and the number of control leads is n. When both m and n are not less than 2, the number of electrode points is between (m+n) and (m×n); otherwise, the number of electrode points is (m×n).

[0014] Optionally, the sensor is an active sensor and includes at least an active element; the multiplexing device is a thin-film transistor and includes at least a source, a gate, and a drain; wherein the gate is used to control the conduction of the source and the drain.

[0015] This invention provides an implantable electrode assembly based on multiplexing, comprising: a sensor, a multiplexing device, a package, and a flexible substrate. The sensor contacts biological brain tissue to acquire electroencephalogram (EEG) signals. The EEG signals acquired by the sensor are then transmitted to the multiplexing device via the package, and the multiplexing device then transmits the received EEG signals to an external device. The package includes at least two layers of organic material and at least one layer of metal material. The flexible substrate supports the multiplexing device. In other words, at least two layers of organic material prevent cerebrospinal fluid from flowing from the sensor to the multiplexing device, and at least one layer of metal material transmits the EEG signals from the sensor to the multiplexing device. This three-layer structure prevents cerebrospinal fluid from contacting the multiplexing device, avoiding short circuits in the electrode assembly and preventing electrode damage. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of an electrode provided in an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of an electrode from another angle, provided as an embodiment of the present invention.

[0018] Figure 3This is a schematic diagram of an electrode from another angle, provided as an embodiment of the present invention.

[0019] Figure 4 A schematic diagram of a prior art electrode provided for an embodiment of the present invention.

[0020] Figure 5 This is a schematic diagram of a thin-film transistor structure provided in an embodiment of the present invention.

[0021] Explanation of reference numerals: 10, Electrode assembly; 11, Sensor device; 111, First interface of the sensor device; 12, Package; 121, First organic layer; 122, Second organic layer; 123, First metal layer; 13, Multiplexing device; 131, First multiplexing layer; 1311, First interface of the multiplexing device; 132, Second multiplexing layer; 133, Third multiplexing layer; 134, Fourth multiplexing layer; 135, Fifth multiplexing layer; 130, First region; 1301, Electrode point; 1302, Acquisition lead; 1303, Control lead; 1304, Interface; 14, Flexible substrate Detailed Implementation

[0022] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of the implantable brain-computer interface electrodes proposed according to the present invention. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0023] like Figure 1 , Figure 2 , Figure 3As shown, an embodiment of the present invention proposes an implantable electrode 10 based on multiplexing, comprising: a sensor 11, a multiplexing device 13, a package 12, and a flexible substrate 14. The sensor 11 contacts biological brain tissue to acquire electroencephalogram (EEG) signals. The sensor 11 can be made of flexible material, which is more suitable for conforming to the cerebral cortex and avoiding damage to brain nerves; or it can be made of rigid material, which is more suitable for high-quality capture of neural signals. The multiplexing device 13 is connected to the sensor 11 through the package 12. After the sensor 11 acquires the EEG signals, it transmits them to the multiplexing device 13 through the package 12. The multiplexing device 13 then transmits the EEG signals to an external device via leads. The external device can be an external interface 134, an external data parsing device, or an external forwarding device, etc. The package 12 comprises two layers of organic material and one layer of metal material, meaning that there is a three-layer structure between the sensor 11 and the multiplexing device 13 to prevent cerebrospinal fluid from flowing from the sensor 11 into the multiplexing device 13. In this embodiment, the encapsulation 12 comprises two layers of organic material and one layer of metal material. In other embodiments, the encapsulation 12 may also comprise three or more layers of organic material and two or more layers of metal material.

[0024] The metal layer includes a first metal layer 123, which can be made of one or more of the following: molybdenum (MO), gold (Au), silver (Ag), copper (Cu), aluminum (Al), titanium (Ti), chromium (Cr), platinum (Pt), etc. In other words, a first metal layer 123 is disposed between the sensing device 11 and the multiplexing device 13, and the sensing device 11 transmits the biological electroencephalogram (EEG) signals to the multiplexing device 13 through the first metal layer 123. Specifically, one end of the first metal layer 123 is attached to the sensing device 11, and the other end of the first metal layer 123 is attached to the multiplexing device 13.

[0025] The two organic material layers include a first organic layer 121 and a second organic layer 122. The first organic layer 121 and the second organic layer 122 can be one or more of the following: polyimide (PI), parylene, hydrogel, resin, polydimethylsiloxane (PDMS), polyurethane (PU), silicone rubber, etc. In other words, a first organic layer 121 and a second organic layer 122 are also provided between the sensor device 11 and the multiplexing device 13. Specifically, the portion of the multiplexing device 13 that is attached to the first metal layer 123 is called the first interface 1311 of the multiplexing device, and the portion of the sensor 11 that is attached to the first metal layer 123 is called the attached portion, which is also called the first interface 111 of the sensor 11. Simultaneously, the portion of the first metal layer 123 that is attached to the multiplexing device 13 is called the first surface of the first metal layer, the portion of the first metal layer 123 that is attached to the sensor 11 is called the second surface of the first metal layer, and the portion of the first metal layer 123 that is attached to the first organic layer 121... The third surface of the first metal layer is referred to as the third surface of the first metal layer, and the portion of the first metal layer 123 that is attached to the second organic layer 122 is referred to as the fourth surface of the first metal layer. At the same time, the first organic layer 121 is attached to the sensor 11, the first metal layer 123, and the second organic layer 122 respectively to form a first sealed passage to prevent cerebrospinal fluid from flowing into the multiplexing device 13. The second organic layer 122 is attached to the first metal layer 123, the first organic layer 121, and the multiplexing device 13 respectively to form a second sealed passage to prevent cerebrospinal fluid from flowing into the multiplexing device 13.

[0026] Specifically, the multiplexing device 13 includes at least: a first multiplexing layer 131, a second multiplexing layer 132, a third multiplexing layer 133, a fourth multiplexing layer 134, and a fifth multiplexing layer 135. The first multiplexing layer 131 can be titanium (Ti) or gold (Au), the second multiplexing layer 132 can be silicon dioxide (SiO2), the third multiplexing layer 133 can be lanthanum-doped indium zinc oxide (Ln-IZO), the fourth multiplexing layer 134 can be silicon dioxide (SiO2) or silicon nitride (SiNx), and the fifth multiplexing layer 135 can be molybdenum (Mo).

[0027] Furthermore, the first interface 1311 of the multiplexing device and the first interface 111 of the sensor are provided with a preset distance in the horizontal direction, and the preset distance is greater than 0. That is to say, there is a preset distance between the interfaces of the two, and since they are blocked by the first sealed passage and the second sealed passage, extending the preset distance can reduce the risk of cerebrospinal fluid flowing into the multiplexing device 13.

[0028] Specifically, the preset distance ranges from 10um to 200mm, for example: the preset distance is 10um, or 20um, or 50um, or 100um, or 200um, etc.

[0029] Specifically, setting the first metal layer 123 into a letter-shaped configuration with a zigzag structure can extend the horizontal distance between the first interface 1311 of the multiplexing device and the first interface 111 of the sensor, for example, a T-shape, Z-shape, or L-shape. In contrast, the traditional method lacks a first organic layer 121 and a second organic layer 122, thus lacking a first and second sealed passage. Furthermore, the horizontal distance between the first interface 1311 of the multiplexing device and the first interface 111 of the sensor is zero, meaning both interfaces are in the same vertical direction. This significantly increases the risk of cerebrospinal fluid flowing into the multiplexing device 1311, greatly increasing the probability of a short circuit in the multiplexing path.

[0030] Furthermore, such as Figure 4 As shown, traditional implantable devices do not have a multiplexing device 13. Instead, they directly transmit the EEG signals acquired by the sensor 11 to an external device via leads. This structure presents several problems: Firstly, the need to transmit large amounts of data necessitates numerous leads made of conductive material. This increases electrode size and craniotomy area, complicating electrode implantation surgery and increasing the risk of nerve damage due to friction between the leads and brain tissue. Secondly, the large number of leads occupies space on the electrode 10, reducing the number of electrode points 131 and thus lowering the electrode array density, limiting spatial resolution and affecting signal acquisition. Furthermore, the large number of leads makes connecting the electrodes to external systems difficult, further restricting the increase in the number of electrode points 131. This solution employs a multiplexing device 13, which can multiplex channels, reducing the number of leads without compromising transmission efficiency, simplifying external electrode connections, increasing the usable area, and increasing the number of electrode points 131. This results in high spatial resolution EEG signal acquisition while simultaneously reducing the risk of nerve damage caused by the numerous electrode leads.

[0031] Furthermore, the multiplexing device 13 is disposed on the surface of the flexible substrate 14, and the multiplexing device 13 is supported by the flexible substrate 14. It can be prepared by directly fabricating the multiplexing device 13 on the surface of the flexible substrate 14 using microelectronic processes; it can also be prepared by transferring the multiplexing device 13 onto the surface of the flexible substrate 14; or it can be prepared by other processes.

[0032] Specifically, the implantable electrode 10 in this solution can be an ECoG electrode (traditionally known as a semi-implantable neural electrode), a needle-like insertion electrode (traditionally known as a fully implantable neural electrode), or some other type of implantable electrode. The biological organism in this solution can be a human, pig, monkey, mouse, or other organism. The flexible substrate 14 can be any flexible substrate 14 compatible with the process of the multiplexing device 13, commonly made of one or more materials such as polyimide, SU-8, PDMS, pyrene, and polyethylene terephthalate. The multiplexing device 13 can be a thin-film transistor, and any thin-film transistor with switching function that can be configured into a multiplexing array, such as a metal oxide thin-film transistor, a silicon thin-film transistor, a two-dimensional material transistor, or an organic thin-film transistor.

[0033] Specifically, encapsulation component 12 refers to any type of thin layer used for waterproofing and encapsulation protection. This can be an organic material layer such as polyimide, SU-8, PDMS, pyrene, or polyethylene terephthalate, or an inorganic material layer such as silicon dioxide, silicon nitride, or alumina.

[0034] Furthermore, the first region 130 of the multiplexing device 13 is provided with multiple electrode points 131 and multiple leads; the multiple electrode points 131 are used to acquire EEG signals, and the multiple leads are used to transmit EEG signals; one end of the multiple leads is connected to the multiplexing device 13, and the other end of the multiple leads is connected to the electrode interface 134. That is to say, unlike traditional electrodes, where the electrode points 131 are directly connected to multiple leads for transmission, in this solution, one end of the multiple leads is connected to the multiplexing device 13, and the EEG signals are transmitted from the multiplexing device 13 to external devices.

[0035] The sensor 11 corresponds to the electrode point 131 of the multiplexing device 13, and the electrode point 131 is the point where the sensor 11 and the multiplexing device 13 come into contact. That is to say... Figure 1 The diagram shows the structure of the sensor 11 before it is bonded to the multiplexer 13, and the diagram shows the structure of the sensor 11 after it is bonded to the multiplexer 13.

[0036] The first region 130 refers to the surface region of the multiplexing device 13, that is... Figure 2 It includes the region formed by each electrode point 131.

[0037] Furthermore, the multiple leads include at least: a data acquisition lead 132 and a control lead 133; wherein, the data acquisition lead 132 is used to transmit EEG signals to an external device; and the control lead 133 is used to send control signals to the multiplexing device 13.

[0038] Furthermore, the number of acquisition leads is m, and the number of control leads is n, both of which are greater than 0. When both m and n are not less than 2, the number of electrode points 131 is between (m+n) and (m×n); otherwise, the number of electrode points is (m×n). In other words, due to the multiplexing device 13, the number of leads can be reduced, and the number of electrode points 131 can be greater than the number of leads. For example, if the number of electrode points 131 is 10000, without the multiplexing device 13, the number of leads would be 10000. With the multiplexing device 13, the number of acquisition leads could be 100, and the number of control leads could be 100, resulting in a total of 200 leads; or the number of acquisition leads could be 200, and the number of control leads could be 50, resulting in a total of 250 leads. This reduces the number of leads, decreases the wiring area, increases the usable space for electrode points 131, improves the electrode point density, and increases the spatial resolution of EEG signal acquisition.

[0039] Furthermore, the number of acquisition leads is m, and the number of control leads is n, both of which are greater than 0. When both m and n are not less than 2, the number of electrode points 131 is between (m+n) and (m×n); otherwise, the number of electrode points is (m×n). In other words, a higher detection density is achieved when the total number of leads is n+m and the number of electrode points 131 is between (m+n) and (m×n). For example, if the total number of leads is 200 and there is no multiplexing device 13, the number of electrode points 131 will be 200. If there is a multiplexing device 13, the number of acquisition leads can be 100, the number of control leads can be 100, and the number of electrode points 131 can be 10,000; the number of acquisition leads can be 50, the number of control leads can be 150, and the number of electrode points 131 can be 7,500; or the number of acquisition leads can be 120, the number of control leads can be 80, and the number of electrode points 131 can be 8,400, thereby increasing the number of electrode points 131 and improving the throughput of EEG signal recording.

[0040] Furthermore, sensor 11 can be a passive or active sensor; an active sensor includes a power supply element. That is, sensor 11 can be a passive sensor, such as a metal layer, the material of which can be one or more of molybdenum (MO), gold (Au), silver (Ag), copper (Cu), aluminum (Al), titanium (Ti), chromium (Cr), platinum (Pt), etc. Sensor 11 can also be an active sensor with functional elements, such as a thin-film transistor, which can be a metal oxide thin-film transistor, a silicon thin-film transistor, a two-dimensional material transistor, an organic thin-film transistor, etc.

[0041] Furthermore, the multiplexing device 13 includes at least: a source, a gate, and a drain; wherein the gate is used to control the conduction of the source and the drain.

[0042] Specifically, such as Figure 5 As shown, a single thin-film transistor has three ports: source, gate, and drain. When a high level is applied to the gate, the source and drain are connected. At this time, the signal from sensor 11 can travel from the drain to the source through the thin-film transistor. The source and drain can be interchanged without affecting the principle or effect.

[0043] Taking a 64×64 EEG with a total of 4096 channels as an example, the 64 gate control lines of the thin-film transistor array are connected to the control module, and the 64 source recording lines are connected to the recording module. First, when gate line 1 (G1) is high and the other signal lines are low, all signals acquired by the recording module at this time come from sensor 11 controlled by line G1, and this time is recorded as t1. Then, gate line 2 (G2) is high and the other signal lines are low, so at this time t2, all signals acquired by the recording module come from sensor 11 controlled by line G2. Next, the above steps are repeated until gate line 64 (G64) is high and the other signal lines are low. The recording module completes the traversal of all channels after stage t64. Finally, the time from t1 to t64 is shortened as much as possible, and the above process is repeated quickly to achieve multiplexed scanning recording of all pathways.

[0044] Specifically, taking metal oxide thin film transistor arrays as an example, they are fabricated into flexible electrodes, with two types of high-density brain electrodes: 32×32=1024 channels and 64×64=4096 channels. The 1024-channel device has only 70 leads, and the 4096-channel device has only 134 leads.

[0045] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An implantable electrode assembly based on multiplexing, characterized in that, include: Sensor devices, multiplexing devices, packaging components, and flexible substrates; The sensor is in contact with biological brain tissue and is used to acquire electroencephalogram (EEG) signals. The multiplexing device is connected to the sensor device through the package and is used to transmit the received EEG signal to an external device. The encapsulation component comprises at least two layers of organic material and at least one layer of metal material; The flexible substrate is used to support the multiplexing device.

2. The electrode assembly according to claim 1, characterized in that, The package includes a first metal layer, a first surface of the first metal layer is attached to a first interface of the multiplexing device, a second surface of the first metal layer is attached to a first interface of the sensor, and the first interface of the multiplexing device and the first interface of the sensor are provided with a preset distance in the horizontal direction.

3. The electrode assembly according to claim 2, characterized in that, The preset distance ranges from 10µm to 200µm.

4. The electrode assembly according to claim 2, characterized in that, The package further includes a first organic layer and a second organic layer; The third surface of the first metal layer is bonded to the first organic layer, and the fourth surface of the first metal layer is bonded to the second organic layer.

5. The electrode assembly according to claim 4, characterized in that, The first metal layer has a letter-shaped structure with a zigzag pattern.

6. The electrode assembly according to claim 5, characterized in that, The first metal layer has a T-shaped form.

7. The electrode assembly according to claim 1, characterized in that, The first region of the multiplexer is provided with multiple electrode points, and the second region of the multiplexer is provided with multiple leads; The first region includes the second region, the plurality of electrode points are used to acquire electroencephalogram (EEG) signals, and the plurality of leads are used to transmit the EEG signals.

8. The electrode assembly according to claim 7, characterized in that, The plurality of leads includes at least: acquisition leads and control leads; The acquisition lead is used to transmit the electroencephalogram (EEG) signal to an external device. The control lead is used to send control signals to the multiplexing device.

9. The electrode assembly according to claim 7, wherein the number of acquisition leads is m and the number of control leads is n, and when both m and n are not less than 2, the number of electrode points is between (m+n) and (m×n); otherwise, the number of electrode points is (m×n).

10. The electrode assembly according to claim 7, characterized in that, The sensor is an active sensor and includes at least: an active element; The multiplexing device is a thin-film transistor and includes at least a source, a gate, and a drain; wherein the gate is used to control the conduction of the source and the drain.

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