Multi-channel flexible microneedle electrode and method of making

Abstract

The application provides a multi-channel flexible microneedle electrode and a preparation method thereof, and the multi-channel flexible microneedle electrode comprises: a flexible substrate, the flexible substrate is provided with a plurality of through holes, the plurality of through holes all penetrate from a first side of the flexible substrate to a second side of the flexible substrate; a plurality of microneedles, the plurality of microneedles are all arranged on the first side, each microneedle is electrically connected with the surface of one through hole, and the surface of the through hole and the surface of the microneedle are made of conductive material; and a wiring layer, the wiring layer is arranged on the second side, the wiring layer has a plurality of first connectors and a plurality of second connectors, the first connectors are arranged on the through holes and are electrically connected with the surfaces of the through holes, and the second connectors are used for leading in or leading out electrical signals. The multi-channel flexible microneedle electrode and the preparation method thereof can collect multi-channel bioelectric signals or can apply multi-channel bioelectric signal stimulation to organisms, and the precision of bioelectric signal collection or electrical stimulation is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of biomedical technology, and in particular to a multi-channel flexible microneedle electrode and a preparation method thereof. BACKGROUND

[0002] The organs, tissues and cells of a living organism undergo potential and polarity changes during life activities, and a constantly changing electric field can be generated in the living organism. An electrophysiological electrode can realize the recording and stimulation of biological electrophysiological signals, and has become an important tool for studying the nervous system, and is widely used in the mechanism research and treatment of Parkinson's disease and epilepsy and the like. As a medium for interaction between a machine and a living organism, the electrophysiological electrode is expected to assist the recovery and enhancement of the function of the living organism, and has great research value.

[0003] The current electrophysiological microneedle electrode has great wiring difficulty, limited electrode density, and is difficult to import or export multi-channel biological electric signals, thereby limiting the application scenarios of the biological electric signals. SUMMARY

[0004] The present application provides a multi-channel flexible microneedle electrode and a preparation method thereof, to solve the defects of the prior art electrophysiological microneedle electrode, such as great wiring difficulty, limited electrode density, difficulty in importing or exporting multi-channel biological electric signals, and limitation of the application scenarios of the biological electric signals, so as to realize the collection of multi-channel biological electric signals, or the application of multi-channel biological electric signal stimulation to a living organism, and improve the precision of biological electric signal collection or electrical stimulation.

[0005] The present application provides a multi-channel flexible microneedle electrode, which comprises:

[0006] A flexible substrate provided with a plurality of through holes, each of the through holes penetrating from a first side of the flexible substrate to a second side of the flexible substrate;

[0007] A plurality of microneedles, each of the microneedles being arranged on the first side, each of the microneedles being electrically connected to the surface of one of the through holes, and the surface of the through hole and the surface of the microneedle being made of a conductive material;

[0008] A wiring layer arranged on the second side, the wiring layer having a plurality of first connectors and a plurality of second connectors, each of the first connectors being arranged on the through hole and being electrically connected to the surface of the through hole, and each of the second connectors being used for importing or exporting an electric signal.

[0009] In some embodiments, each of the first connectors is electrically connected to the surface of one of the through holes, each of the second connectors is electrically connected to one of the first connectors, and each of the second connectors is used for importing or exporting an electric signal.

[0010] In some embodiments, each of the first connectors is electrically connected to the surface of a plurality of the through holes, each of the second connectors is correspondingly electrically connected to one of the first connectors, and each of the second connectors is used for leading in or leading out multi-channel electrical signals.

[0011] In some embodiments, the flexible substrate has a plurality of through hole groups, the distance between adjacent through hole groups is greater than a target distance, each of the first connectors is electrically connected to the surface of one of the through hole groups, and each of the through hole groups comprises a plurality of the through holes that are electrically connected to each other.

[0012] In some embodiments, the multi-channel flexible microneedle electrode further comprises a first insulating layer covering a side of the wiring layer away from the flexible substrate.

[0013] In some embodiments, the microneedle comprises a needle body and a needle tip.

[0014] The multi-channel flexible microneedle electrode further comprises:

[0015] a second insulating layer covering the surface of the plurality of the through holes and the needle body of the plurality of the microneedles, and the needle tip of the plurality of the microneedles being exposed outside the second insulating layer.

[0016] In some embodiments, the microneedle has a conical shape, a wheat grain shape or a sharp cone shape.

[0017] In some embodiments, the through hole has a diameter of 10 μm to 200 μm.

[0018] Alternatively, the flexible substrate has a thickness of 5 μm to 100 μm.

[0019] Alternatively, the microneedle has a diameter of 50 μm to 200 μm.

[0020] Alternatively, the microneedle has a length of 0.3 mm to 2 mm.

[0021] The present application also provides a preparation method of a multi-channel flexible microneedle electrode, which is applied to any one of the multi-channel flexible microneedle electrodes described above, and comprises the following steps:

[0022] determining a male mold;

[0023] performing a mold turning process based on the male mold to obtain a female mold;

[0024] covering the female mold with a target material, performing high-temperature solidification and mechanical polishing to obtain a flexible substrate having a plurality of through holes and a plurality of microneedles;

[0025] A wiring layer is made on the second side of the flexible substrate, and a first joint in the wiring layer is arranged in the through hole;

[0026] A conductive material is coated on the surface of each micro needle and each through hole to electrically connect the micro needle with the corresponding through hole and the corresponding first joint.

[0027] The preparation method of the multi-channel flexible micro needle electrode provided by the application further comprises: covering a second insulating layer on the surface of the plurality of through holes and the surface of the plurality of micro needles;

[0028] Photoresist is coated on the surface of the second insulating layer, and the insulating material covering the tip of the micro needle is removed to expose the tip of the micro needle outside the second insulating layer.

[0029] The multi-channel flexible micro needle electrode and the preparation method provided by the application can electrically connect the through hole and the micro needle one by one by arranging a plurality of through holes on the flexible substrate, arrange a wiring layer on the side of the flexible substrate away from the micro needle, and use a plurality of second joints to lead out multi-channel electrical signals, without limiting the density of the wiring layer and the density of the micro needle, so that multi-channel bioelectrical signals can be collected, or multi-channel bioelectrical signal stimulation can be applied to the organism, and the precision of bioelectrical signal collection or electrical stimulation is improved. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0031] Figure 1 is one of the structure schematic diagrams of the multi-channel flexible micro needle electrode provided by the application;

[0032] Figure 2 is one of the preparation method schematic diagrams of the multi-channel flexible micro needle electrode provided by the application;

[0033] Figure 3 is the second structure schematic diagram of the multi-channel flexible micro needle electrode provided by the application;

[0034] Figure 4 is the second preparation method schematic diagram of the multi-channel flexible micro needle electrode provided by the application;

[0035] Figure 5 is the third structure schematic diagram of the multi-channel flexible micro needle electrode provided by the application;

[0036] Figure 6 Fig. 4 is a structural schematic diagram of a multi-channel flexible microneedle electrode according to the present application;

[0037] Figure 7 Fig. 5 is a structural schematic diagram of a plurality of microneedles of a multi-channel flexible microneedle electrode according to the present application;

[0038] Figure 8 Fig. 7 is a schematic diagram of a third step of a method for manufacturing a multi-channel flexible microneedle electrode according to the present application;

[0039] Figure 9 Fig. 8 is a schematic diagram of a fourth step of a method for manufacturing a multi-channel flexible microneedle electrode according to the present application;

[0040] Figure 10 Fig. 9 is a schematic diagram of a fifth step of a method for manufacturing a multi-channel flexible microneedle electrode according to the present application;

[0041] Figure 11 Fig. 5 is a structural schematic diagram of a plurality of microneedles of a multi-channel flexible microneedle electrode according to the present application;

[0042] Reference Signs:

[0043] 10: flexible substrate; 11: through hole; 12: first side surface; 13: second side surface; 20: microneedle; 21: needle body; 22: needle tip; 30: wiring layer; 31: first joint; 32: second joint; 40: through hole group; 50: first insulating layer; 60: second insulating layer; 70: male mold; 80: female mold. DETAILED DESCRIPTION

[0044] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below in conjunction with the drawings in the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0045] The multi-channel flexible microneedle electrode and the method for manufacturing the same according to the present application will be described below in conjunction with Figures 1-11 the drawings.

[0046] As shown in Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 11 , the present application provides a multi-channel flexible microneedle electrode, which comprises a flexible substrate 10, a plurality of microneedles 20 and a wiring layer 30.

[0047] The flexible substrate 10 is provided with a plurality of through holes 11, each of which penetrates from the first side 12 to the second side 13 of the flexible substrate 10.

[0048] It can be understood that the flexible substrate 10 can adapt to the shape of the organism, for example, the flexible substrate 10 can be self-adaptively adjusted according to the shape of the skin tissue, and the material of the flexible substrate 10 is not limited herein.

[0049] The flexible substrate 10 can have a first side 12 and a second side 13, the first side 12 can be used to attach to the surface of the organism, for example, the first side 12 can be attached to the scalp of the organism, and the second side 13 is a side away from the first side 12.

[0050] The flexible substrate 10 can be provided with a plurality of through holes 11, each of which penetrates the first side 12 and the second side 13 of the flexible substrate 10 along the thickness direction of the flexible substrate 10.

[0051] The plurality of microneedles 20 are arranged on the first side 12, each microneedle 20 is electrically connected to the surface of a through hole 11, and the surface of the through hole 11 and the surface of the microneedle 20 are made of conductive material.

[0052] It can be understood that the plurality of microneedles 20 extend outward from the first side 12 of the flexible substrate 10, and each microneedle 20 can be arranged beside a through hole 11, that is, one microneedle 20 can be matched with one through hole 11, and the distance between the mutually matched microneedle 20 and the through hole 11 can be less than a predetermined distance, and the distance between the mutually matched microneedle 20 and the through hole 11 can be 100 μm-1 mm, for example, 500 μm.

[0053] Of course, each through hole can also connect a plurality of microneedles, for example, a plurality of microneedles can be electrically connected to one first connector through one through hole, and the number of microneedles and the number of through holes are not limited in the embodiment, and the person skilled in the art can select the corresponding relationship between the number of microneedles and the number of through holes according to the actual situation.

[0054] The surface of the through hole 11 and the surface of the microneedle 20 can be made of conductive material, and the surface of the mutually matched through hole 11 can be electrically connected to the surface of the microneedle 20.

[0055] The wiring layer 30 is arranged on the second side 13, and the wiring layer 30 has a plurality of first connectors 31 and a plurality of second connectors 32, the first connector 31 is arranged on the through hole 11 and is electrically connected to the surface of the through hole 11, and the second connector 32 is used to import or export electrical signals.

[0056] It can be understood that the wiring layer 30 can be attached to the second side 13, the wiring layer 30 can have a plurality of first contacts 31 and a plurality of second contacts 32, the first contacts 31 can be electrically connected to the second contacts 32, the first contacts 31 and the second contacts 32 are both made of conductive material, the first contacts 31 can extend into the through holes 11 and be electrically connected to the surfaces of the through holes 11, thus the microneedle 20, the through hole 11, the first contact 31 and the second contact 32 form a communication circuit.

[0057] It is worth noting that one microneedle 20 is electrically connected to one through hole 11, one first contact 31 can be electrically connected to one through hole 11, one first contact 31 can also be electrically connected to a plurality of through holes 11, that is, one first contact 31 can be electrically connected to a plurality of microneedles 20, the number of through holes 11 connected to the first contact 31 is not limited here, and the number of microneedles 20 connected to the first contact 31 is also not limited, the second contact 32 can output the electrical signal collected by the microneedle 20 or transmit the applied stimulation electrical signal to the microneedle 20, each second contact 32 forms a transmission channel, and a plurality of second contacts 32 form a plurality of transmission channels, which can output multi-channel electrical signals.

[0058] The multi-channel flexible microneedle electrode can be electrically connected to an external device through the second contact 32, and can output multi-channel electrical signals to the external device, which can be an electroencephalogram acquisition or electrical stimulation device, an electrocardiogram acquisition or electrical stimulation device, or other electrical signal acquisition or electrical stimulation device.

[0059] The multi-channel flexible microneedle electrode can be used for electromyography (EMG), electroencephalography (EEG), electrocorticography (ECoG) and local field potential signal acquisition and electrical stimulation.

[0060] In use, the flexible substrate 10 can be attached to the skin of a living body, the microneedle 20 can penetrate the stratum corneum or the cerebral cortex, reduce the skin impedance, increase the contact area with the living body, and obtain electrical signals with higher signal-to-noise ratio, the microneedle 20 can output the electrical signals through the through hole 11, the first contact 31 and the second contact 32, and the plurality of second contacts 32 can output multi-channel electrical signals.

[0061] It is worth noting that the through hole 11 is adopted to conduct the electrical signal in the embodiment, and the double-layer interconnection mode of the front and back surfaces can improve the electrode density, reduce the dependence on the line width, and enable the wiring layer 30 and the microneedle 20 to be distributed on the two sides of the flexible substrate 10, so that the wiring layer 30 does not occupy the position of the microneedle 20, thereby improving the density of the wiring and the density of the microneedle 20, that is, the high-density arrangement of the microneedle 20 can be realized, the high-density collection of the electrical signal can be realized, or high-density electrical stimulation can be realized, and the insulation between the microneedles 20 can be facilitated, and the precision of the electrical signal collection or electrical stimulation can be improved. The multi-channel flexible microneedle electrode provided by the application realizes one-to-one electrical connection between the through hole 11 and the microneedle 20 by arranging a plurality of through holes 11 on the flexible substrate 10, and arranges the wiring layer 30 on the side of the flexible substrate 10 away from the microneedle 20, and uses a plurality of second joints 32 to lead out the multi-channel electrical signal, so that the density of the wiring layer 30 and the density of the microneedle 20 are not limited, the multi-channel bioelectrical signal can be collected, or the multi-channel bioelectrical signal stimulation can be applied to the organism, and the precision of the bioelectrical signal collection or electrical stimulation is improved.

[0062] As shown in Figure 2 , Figure 3 and Figure 11 , in some embodiments, each first joint 31 is electrically connected to the surface of one through hole 11, each second joint 32 is electrically connected to one first joint 31, and each second joint 32 is used to lead out one channel of electrical signal collected or stimulated by the microneedle 20.

[0063] It can be understood that in the embodiment, each microneedle 20 is connected to one through hole 11, each through hole 11 is connected to one first joint 31, and each first joint 31 is connected to one second joint 32, so that each microneedle 20 can serve as an independent channel, each microneedle 20 collects one channel of electrical signal, or applies one channel of electrical stimulation to the organism, thereby further improving the precision of the electrical signal collection or electrical stimulation.

[0064] As shown in Figure 5 , in some embodiments, each first joint 31 is electrically connected to the surface of one through hole 11, each second joint 32 is electrically connected to one first joint 31, and each second joint 32 is used to lead out one channel of electrical signal collected or stimulated by the microneedle 20.

[0065] It can be understood that, unlike the previous embodiment, each first joint 31 in the embodiment is electrically connected to the surface of a plurality of through holes 11, so that each second joint 32 is electrically connected to a plurality of through holes 11, when the microneedle 20 is used for electrical signal collection, each second joint 32 can lead out the electrical signals collected by a plurality of microneedles 20, and when the microneedle 20 is used for electrical stimulation, each second joint 32 can transmit one channel of electrical signal to a plurality of microneedles 20 to apply electrical stimulation to the organism.

[0066] Since the electrical signal collected by each second joint 32 is the electrical signal collected by multiple microneedles 20, the strength of the electrical signal can be improved, and the strength of the electrical signal collection and electrical stimulation can be improved.

[0067] As shown in Figure 5 some embodiments, the flexible substrate 10 has a plurality of via groups 40, the distance between adjacent via groups 40 is greater than the target distance, each first joint 31 is electrically connected to the surface of a via group 40, and each via group 40 includes a plurality of vias 11 that are electrically connected to each other.

[0068] It can be understood that the vias 11 on the flexible substrate 10 can form a plurality of via groups 40, each via group 40 can include a plurality of vias 11, for example, each via group 40 can include 16 vias 11, and one via group 40 can correspond to 16 microneedles 20. Of course, the number of vias 11 in the via group 40 is not limited here, and the number of vias 11 and microneedles 20 is not necessarily the same. The surfaces of the plurality of vias 11 in each via group 40 are electrically connected to each other, and each first joint 31 is electrically connected to the surface of a via group 40. Then one first joint 31 will be able to transmit the electrical signal of one via group 40. When the microneedles 20 are used to collect electrical signals, the plurality of vias 11 in one via group 40 correspond to a plurality of microneedles 20, and the electrical signals collected by the plurality of microneedles 20 are gathered in one via group 40. The electrical signal is transmitted to the second joint 32 through one first joint 31, and is led out through the second joint 32; when the microneedles 20 are used for electrical stimulation, the plurality of vias 11 in one via group 40 can receive an electrical signal transmitted by one first joint 31, and the plurality of microneedles 20 are used to apply the electrical signal.

[0069] The distance between adjacent via groups 40 is greater than the target distance, that is, the different via groups 40 are spaced apart by a certain distance, and each via group 40 can collect electrical signals or perform electrical stimulation on one part. This can increase the coverage area of a single collection point and further reduce the contact impedance to obtain an electrical signal with a higher signal-to-noise ratio.

[0070] As shown in Figure 1 , Figure 3 , Figure 4 and Figure 6 in some embodiments, the multichannel flexible microneedle electrode further comprises: a first insulating layer 50, the first insulating layer 50 covers the side of the wiring layer 30 away from the flexible substrate 10.

[0071] It can be understood that the first insulating layer 50 can be coated on the side of the wiring layer 30 away from the flexible substrate 10, the first insulating layer 50 and the second side 13 of the flexible substrate 10 coat the wiring layer 30 therein, only leaving the second joint 32 of the wiring layer 30 to transmit the electrical signal, so as to avoid the electrical signal transmitted by the wiring layer 30 being interfered by the external conductor, and to eliminate interference and improve the reliability of the electrical signal acquisition or electrical stimulation.

[0072] As shown in Figure 6 some embodiments, the microneedle 20 includes a needle body 21 and a needle tip 22.

[0073] The diameter of the needle body 21 can be 50 μm to 200 μm, such as 100 μm, and the diameter of the needle tip 22 can be 10 μm to 50 μm, such as 30 μm.

[0074] The multi-channel flexible microneedle electrode further includes a second insulating layer 60, the second insulating layer 60 coats the surface of the plurality of through holes 11 and the needle body 21 of the plurality of microneedles 20, and the needle tip 22 of the plurality of microneedles 20 is exposed outside the second insulating layer 60.

[0075] It can be understood that most of the microneedle 20 is the needle body 21, which is covered by the second insulating layer 60, and only the needle tip 22 of the microneedle 20 is exposed, which can be used to monitor the action potential generated by a single neuron. Here, by reducing the area of the exposed microneedle 20, it is close to the size of a single neuron, so as to collect the electrical signal of a single neuron, which can be used to analyze the action potential generated by a single neuron, and has great significance for analyzing the function of neurons and understanding the brain wave signal.

[0076] Of course, the microneedle 20 in this embodiment can also be used for electrical stimulation of the organism, which can improve the accuracy of electrical stimulation.

[0077] As shown in Figure 7 some embodiments, the microneedle 20 has a conical shape, a wheat grain shape, or a sharp cone shape.

[0078] In some embodiments, the diameter of the through hole 11 is 10 μm to 200 μm, such as 100 μm; or the thickness of the flexible substrate 10 is 5 μm to 100 μm, such as 8 μm; or the diameter of the microneedle 20 is 50 μm to 200 μm, such as 100 μm; or the length of the microneedle 20 is 0.3 mm to 2 mm, such as 1 mm.

[0079] In some embodiments, the distance between one microneedle 20 and one matched through hole 11 can be 100 μm-1 mm.

[0080] As shown in Figure 2 , Figure 4 ,Figure 8 and Figure 9 As shown in FIG. 8, the application also provides a preparation method of the multi-channel flexible microneedle electrode, which is applied to the multi-channel flexible microneedle electrode in the above embodiment. The preparation method of the multi-channel flexible microneedle electrode comprises: determining a male mold 70; performing mold turning processing based on the male mold 70 to obtain a female mold 80; covering the target material on the female mold 80, and performing high-temperature curing and mechanical polishing processing to obtain a needle tip 22 with a plurality of through holes 11 and a plurality of microneedles 20; manufacturing a wiring layer 30 on the second side 13 of the flexible substrate 10, and arranging a first joint 31 in the wiring layer 30 in the through hole 11; and coating a conductive material on the surface of each microneedle 20 and each through hole 11 to obtain a multi-channel flexible microneedle electrode, wherein the conductive material is used to electrically connect the microneedle 20 with the corresponding through hole 11 and the corresponding first joint 31.

[0081] It can be understood that the rigid male mold 70 with the micropore structure and the microneedle structure can be machined by 3D printing, photoetching or machining, and the material of the male mold 70 includes but is not limited to epoxy resin, polypropylene, silicon and metal. The diameter of the microneedle structure is 50 μm-200 μm, for example, 100 μm, and the height is 0.3 μm-2 mm, for example, 1 mm. The diameter of the micropore structure is 10 μm-200 μm, for example, 100 μm, and the depth is 5 μm-100 μm, for example, 50 μm.

[0082] The rigid male mold 70 can be placed in an uncured polydimethylsiloxane (PDMS) solution, heated at 80°C for 3 h, and the PDMS is turned after curing to obtain a PDMS female mold 80 with micropore and microneedle 20 holes. The female mold 80 can also be made of other flexible or rigid materials other than PDMS.

[0083] The polyimide (PI) solution can be uniformly coated on the female mold 80 by spin coating or blade coating, and placed in a high-temperature environment for curing to form a film to constitute the flexible substrate 10, the thickness is 5 μm-100 μm, for example, 50 μm, and the PI film on the upper surface of the micropore is removed by mechanical polishing to form the through hole 11 on the flexible substrate 10. The material of the flexible substrate 10 can be other flexible materials other than polyimide. The upper surface of the micropore is higher than the flexible substrate 10, and after the polyimide on the upper surface of the micropore is removed, the through hole 11 is formed, while the flexible substrate 10 is still a uniform film at other positions. The formation of the through hole 11 is the key to the subsequent double-sided wiring.

[0084] The wiring layer 30 can be manufactured on the flexible substrate 10 by photoetching, metal mask or other patterning methods, and the wiring material is not limited to titanium, gold, silver, platinum and conductive polymers, etc., and the thickness is 100 nm. Each lead wire is connected with the through hole 11 to form the first joint 31 inside the through hole 11. The diameter of the first joint 31 can also be slightly larger than the diameter of the through hole 11.

[0085] The polyimide solution can be uniformly coated onto the surface of the wiring layer 30 by spin coating or blade coating, and then cured into a film in a high-temperature environment to form a first insulating layer 50. The material of the first insulating layer 50 is not limited to polyimide, and the thickness is 5μm-100μm, for example, 50μm. A second connector 32 is provided for the electrical connection between the electrode and the external circuit.

[0086] After further molding, microneedles 20 with the same dimensions as the microneedle structure on the male mold 70 will be formed.

[0087] Because the adhesion of the lead material and the first insulating layer 50 is greater than that of the PDMS micropillars, the first connector 31 will transfer from the surface of the PDMS micropillars to the first insulating layer 50. The first connector 31 is a bridge connecting the conductive material of the microneedle 20 and the wiring layer 30.

[0088] A conductive layer is formed on one side of the microneedle 20 using photolithography, a metal mask, or other patterning methods. The electrode material is not limited to titanium, gold, silver, platinum, or conductive polymers, and the thickness is 100 nm. The electrode points cover the surfaces of the microneedle 20 and the via 11. The bottom of the via 11 is a first connector 31, and each first connector 31 corresponds to a lead wire to realize the lead-out of the electrode point.

[0089] like Figure 10 As shown, in some embodiments, the method for fabricating the multi-channel flexible microneedle electrode further includes: covering the surfaces of the plurality of through holes 11 and the surfaces of the plurality of microneedles 20 with a second insulating layer 60; coating the surface of the second insulating layer 60 with photoresist and removing the insulating material covering the tip 22 of the microneedle 20 so that the tip 22 of the microneedle 20 is exposed outside the second insulating layer 60.

[0090] It is understood that after the processing flow of the above embodiments, a second insulating layer 60 can be coated on the surface of the microneedle 20 and the surface of the via 11 by physical vapor deposition or chemical vapor deposition. The material of the second insulating layer 60 includes, but is not limited to, parylene, silicon dioxide and polyimide, and the thickness of the second insulating layer 60 is 1μm-10μm, for example, 5μm.

[0091] A layer of photoresist is spin-coated or scraped onto the surface of the second insulating layer 60, exposing the tip 22 of the microneedle 20 under gravity. After curing, a protective film is formed. Alternatively, a solid film can be placed over the electrode surface and punctured by the microneedle 20 to form a protective film. The function of the protective film is to prevent the second insulating layer 60 underneath from being removed during subsequent etching.

[0092] By etching, chemical etching or laser ablation, etc., the insulating layer at the tip 22 of the microneedle 20 is removed, exposing a bare electrode point with a diameter of 10-50 microns, the rest of the second insulating layer 60 is not affected, the protective film is removed by physical or chemical methods, and a multi-channel flexible microneedle electrode capable of recording action potential and electrical stimulation is obtained.

[0093] The device embodiments described above are merely illustrative, wherein the units described as separate components can or can not be physically separated, and the components displayed as units can or can not be physical units, i.e. they can be located in one place or distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the embodiment scheme according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0094] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A multi-channel flexible microneedle electrode, characterized by, include: A flexible substrate having multiple through holes, each of which extends from a first side surface of the flexible substrate to a second side surface of the flexible substrate. Multiple microneedles are disposed on the first side surface. The microneedles are electrically connected to the surface of the through-hole. The surfaces of the through-hole and the microneedles are made of conductive materials. The microneedles are disposed next to the through-holes corresponding to the microneedles. Each through-hole is connected to multiple microneedles. A wiring layer is disposed on the second side. The wiring layer has a plurality of first connectors and a plurality of second connectors. The first connectors are disposed in the through hole and are electrically connected to the surface of the through hole. The second connectors are used to import or export electrical signals. Each of the first connectors is electrically connected to the surface of the plurality of through holes, each of the first connectors corresponds to a plurality of interconnected microneedles, each of the second connectors is electrically connected to one of the first connectors, and each of the second connectors is used to import or export multiple electrical signals; the needle body of the microneedle is made of the same material as the flexible substrate, the flexible substrate is made of a flexible material, and the microneedles and the flexible substrate are formed based on a molding process.

2. A multi-channel flexible microneedle electrode, characterized by, include: A flexible substrate having multiple through holes, each of which extends from a first side surface of the flexible substrate to a second side surface of the flexible substrate. Multiple microneedles are disposed on the first side surface. The microneedles are electrically connected to the surface of the through-hole. The surfaces of the through-hole and the microneedles are made of conductive materials. The microneedles are disposed next to the through-holes corresponding to the microneedles. Each through-hole is connected to one microneedle. A wiring layer is disposed on the second side. The wiring layer has a plurality of first connectors and a plurality of second connectors. The first connectors are disposed in the through hole and are electrically connected to the surface of the through hole. The second connectors are used to import or export electrical signals. Each of the first connectors is electrically connected to the surface of one of the through holes, each of the first connectors corresponds to one of the microneedles, each of the second connectors is electrically connected to one of the first connectors, and each of the second connectors is used to import or export multiple electrical signals; the needle body of the microneedle is made of the same material as the flexible substrate, the flexible substrate is made of a flexible material, and the microneedle and the flexible substrate are formed based on a molding process.

3. The multi-channel flexible microneedle electrode of claim 1, wherein, The flexible substrate has multiple via groups, the distance between adjacent via groups is greater than the target distance, each first connector is electrically connected to the surface of one of the via groups, each via group includes multiple electrically connected vias, and each via group corresponds to multiple electrically connected microneedles.

4. The multi-channel flexible microneedle electrode according to any one of claims 1-3, wherein, Also includes: A first insulating layer covers the side of the wiring layer opposite to the flexible substrate.

5. The multi-channel flexible microneedle electrode according to any one of claims 1-3, wherein, The microneedle includes a needle body and a needle tip; The multi-channel flexible microneedle electrode also includes: A second insulating layer covers the surface of the plurality of through holes and the needle bodies of the plurality of microneedles, with the tips of the plurality of microneedles exposed outside the second insulating layer.

6. The multi-channel flexible microneedle electrode according to any one of claims 1-3, wherein, The shape of the microneedle is conical, wheat-shaped or pyramidal.

7. The multi-channel flexible microneedle electrode according to any one of claims 1-3, wherein, The diameter of the through hole is 10-200 μm; Or, the thickness of the flexible substrate is 5-100 μm; Or, the diameter of the microneedle is 50-200 μm; Or, the length of the microneedle is 0.3-2 mm.

8. A method of fabricating a multi-channel flexible microneedle electrode, comprising: The method for preparing the multi-channel flexible microneedle electrode as claimed in any one of claims 1-7 comprises: determining a male mold; performing mold turning based on the male mold to obtain a female mold; covering the female mold with a target material, and performing high-temperature curing and mechanical polishing to obtain a flexible substrate with multiple through holes and multiple microneedles; making a wiring layer on the second side of the flexible substrate, and arranging a first connector in the wiring layer in the through hole; coating a conductive material on the surface of each microneedle and each through hole to obtain the multi-channel flexible microneedle electrode, the conductive material being used to electrically connect the microneedle with the corresponding through hole and the corresponding first connector.

9. The method of claim 8, wherein the plurality of flexible microneedle electrodes are prepared by, Further comprising: covering the surface of the multiple through holes and the surface of the multiple microneedles with a second insulating layer; coating photoresist on the surface of the second insulating layer, and removing the insulating material covering the tip of the microneedle to expose the tip of the microneedle outside the second insulating layer.

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