Mutual inductance type brain deformation array sensor and preparation method and application thereof

Abstract

The invention belongs to the technical field of biosensing, and particularly relates to a mutual inductance type brain deformation array sensor and a preparation method and application thereof. According to the invention, a metal material or a conductive polymer is used as a conductive material, an elastomer or parylene is used as an insulating material, an insulating layer-conductive coil-insulating layer sandwich film unit is prepared by micro-nano processing and the like, and a plurality of coil units are connected into a sensing coil array through the insulating layers. The change of tiny deformation of the brain tissue can be effectively detected, so that the method can be used for continuous real-time detection and imaging of the deformation of the brain tissue; the sensor is based on the mutual inductance principle, realizes the time resolution of less than 100 microseconds and the resolution of less than 5 microns according to the corresponding relation between the output voltage and the distance, and has very strong anti-interference capability on the change of cerebrospinal fluid components; according to the sensor, by changing the size and arrangement of the coil units, the detection requirements of to-be-detected objects of different body types and different scenes can be met.

Description

Technical Field

[0001] The present invention belongs to the field of biosensor technology, and specifically relates to a mutual inductance brain deformation array sensor and a preparation method and application thereof. Background Art

[0002] The brain is a highly dynamic system, with chemical, electrical, and mechanical signals constantly changing. Among them, brain deformation, as an important component of mechanical signals, is closely related to internal physiological rhythms as well as external stimuli. For example, regular brain deformation caused by breathing and heartbeat plays a key role in maintaining the balance of brain function, promoting cerebrospinal fluid circulation, and promoting efficient communication between different brain regions. In addition, brain tissue will also respond to external stimuli with deformations, which are not only passive mechanical responses of the brain, but also can serve as indicators of potential pathophysiological processes. For example, during acute cerebral hemorrhage, the outward deformation of the brain caused by the expansion of the hematoma can cause biochemical reactions and aggravate the injury.

[0003] Currently, technologies such as magnetic resonance imaging and ultrasound imaging are often used to study brain deformation and structural changes. However, these methods have significant limitations in capturing dynamic deformation. Magnetic resonance imaging has low temporal and spatial resolution, making it difficult to detect rapid and small deformations caused by heartbeats, etc. Ultrasound imaging is limited to single coronal acquisition and cannot capture the complex deformation interactions between multiple brain regions. In addition, neither of these two technologies can achieve long-term continuous monitoring of freely moving subjects. Therefore, the development of a flexible sensing technology that can monitor brain deformation in real time and with high precision will provide an important tool for studying the dynamic deformation mechanism of the brain and its role in physiological and pathological processes, while providing new possibilities for the early diagnosis and treatment of brain diseases. Summary of the invention

[0004] The purpose of the present invention is to provide a mutual inductance array sensor that can continuously, in real time and with high precision detect dynamic deformation of the brain, as well as a preparation method and application thereof.

[0005] The mutual inductance deformation array sensor provided by the present invention uses metal or conductive polymer as conductive material, elastomer or polyparaxylene as insulating material, and prepares a sandwich film coil unit of insulating layer-conductive coil-insulating layer by laser engraving or etching technology; each coil unit has the characteristics of ultra-thinness and low density, and two coil arrays are constructed as a deformation array sensor, which can effectively detect changes in small deformations of brain tissue and is applied to the detection and imaging of dynamic deformation of the brain. The sensor is based on the principle of mutual inductance, and according to the corresponding relationship between output voltage and distance, it achieves a time resolution of less than 100 microseconds and a distance resolution of less than 5 microns, and has a strong anti-interference ability to changes in cerebrospinal fluid composition; the sensor of the present invention can meet the detection needs of different sizes of objects to be tested and different scenes by changing the size and arrangement of the coil unit.

[0006] The preparation method of the brain deformation array sensor provided by the present invention is as follows:

[0007] (1) Spin-coat a sacrificial layer on the silicon wafer; spin-coat an insulating layer material solution with a mass fraction of 10%-70%, or chemically vapor deposit parylene material to form a substrate insulating layer;

[0008] (2) Transfer the designed conductive coil pattern to the substrate insulating layer to form a conductive coil layer;

[0009] (3) Conduct insulation treatment within the coil turn range between the inner end and the outer end of the conductive coil layer prepared in step (2) to prevent electrical short circuits between overlapping conductive layers within the coil;

[0010] (4) Connect the inner end of the conductive coil layer described in step (2) to the outside through a conductive material;

[0011] (5) Spin-coat an insulating layer material solution with a mass fraction of 10%-70% on the patterned coil, or chemically vapor deposit parylene material as the top insulating layer;

[0012] (6) Through laser engraving treatment, obtain a two-dimensional coil array (M×N) composed of coil units on the silicon wafer;

[0013] (7) Immerse the silicon wafer containing the coil array prepared in step (6) in a dopamine solution to dissolve the sacrificial layer described in step (1), and release to obtain a poly-dopamine modified coil array. Two coil arrays form a sensor, which is used as a sensor for continuously and real-time detecting brain deformation.

[0014] Furthermore:

[0015] The formation of the conductive coil layer described in step (2) includes the following two schemes:

[0016] (1) Deposit a metal material on the substrate insulating layer by thermal evaporation or magnetron sputtering, and transfer the pattern of the mask template to the substrate insulating layer; or,

[0017] (2) Spin-coat a conductive polymer solution or deposit a metal material on the substrate insulating layer, perform photolithography on the conductive layer using a negative photoresist, the developed photoresist is the coil pattern, and transfer the coil pattern of the photoresist to the conductive layer through etching.

[0018] The insulation treatment described in step (3) includes sputtering and depositing an aluminum oxide layer and annealing, spin-coating an insulating layer material solution with a mass fraction of 10%-70% or chemically vapor depositing parylene material, and patterning;

[0019] The insulating layer material is selected from polystyrene-butadiene-styrene block copolymer, polydimethylsiloxane, fluororubber, partially hydrogenated polystyrene-butadiene-styrene block copolymer, and parylene.

[0020] The conductive material in step (4) is a metal material or poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid, polypyrrole, or polythiophene.

[0021] In step (6), the laser engraving makes the conductive coil layer inside the insulating layer, and the coil units are connected by insulating materials. For the two-dimensional coil array (M×N), the number and distribution of detection sites are determined according to the size of the brain tissue area to be covered in the detection scenario, so as to determine the values of M and N.

[0022] The dopamine solution in step (7) is obtained by dissolving dopamine in Tris-HCl aqueous solution, and the proportion of dopamine in Tris-HCl aqueous solution is ≥1.5 mg / mL.

[0023] The conductive coil layer prepared above is a two-dimensional coil array composed of the conductive parts in a number of coil units.

[0024] In the present invention, according to different preparation requirements, the conductive layer and insulating layer can be prepared by methods such as thermal evaporation, magnetron sputtering, spin coating, chemical vapor deposition, etc.; the coil patterning can be carried out by methods such as laser engraving, photolithography, etching, cutting, etc.

[0025] In the present invention, the thickness of the coil unit in the deformation array sensor is ≤5 μm, and the mass density is ≤1.8 g / cm³. Preferably, 2 μm ≤ thickness ≤ 3 μm, and 1.2 g / cm³ ≤ mass density ≤ 1.5 g / cm³.

[0026] In the present invention, the side length or diameter of the coil unit in the deformation array sensor can be determined according to specific application requirements. Preferably, it is 100 μm - 5 mm.

[0027] In the present invention, the brain deformation array sensor is composed of two sets of coil arrays placed opposite to each other; it is divided into: a dispersed array sensor, that is, each coil array is composed of a number of discrete coil units; a mesh array sensor, that is, each coil array is composed of a number of coils connected to each other through an insulating layer. See specifically Figure 15 as shown.

[0028] For the dispersed array sensor, a number of coil units are respectively placed at different positions of the cerebral cortex, and the other set of coil units is fixed on the skull at the corresponding positions. The detection sites correspond one by one in the normal direction. Each sensor detects independently, and the voltage changes at each detection site are read simultaneously, and the deformation changes are converted through the voltage-distance correspondence relationship.

[0029] For a mesh array sensor, when implanted, a mesh coil array is placed on the cerebral cortex, and another mesh coil array is fixed on the skull at the corresponding position. The detection sites correspond one-to-one in the normal direction, and each sensor detects independently. At the same time, the voltage changes at each detection site are read and converted into deformation changes through the voltage-distance correspondence relationship.

[0030] The brain deformation array sensor of the present invention is applicable to the continuous real-time detection and imaging of dynamic deformations of brain tissues of small, medium, and large animals.

[0031] The beneficial effects of the present invention are as follows:

[0032] (1) For the brain deformation array sensor prepared by the present invention, the thickness of the coil unit is ≤ 5 μm, and the mass density is ≤ 1.8 g / cm³, which is similar to the density of brain tissue and significantly lower than that of common biomedical materials, avoiding affecting the intrinsic dynamic deformation of the brain after implantation and having no obvious immune response.

[0033] (2) For the brain deformation array sensor prepared by the present invention, the time resolution is less than 100 μs, the minimum detected deformation change is less than 5 μm, and it has a strong anti-interference ability against changes in the composition of cerebrospinal fluid, and can accurately quantify and image brain deformations.

[0034] (3) The brain deformation array sensor prepared by the present invention can effectively detect brain tissue deformations at multiple sites and large areas, such as distinguishing the brain deformation trends caused by isoflurane inhalation in brain tissue regions of rats close to the superior sagittal sinus and farther away, detecting and imaging brain deformations during mechanical impacts on the brain, and continuously detecting and imaging the processes of cerebral hemorrhage and cerebral edema, providing guidance for the diagnosis and treatment of various brain diseases and providing an effective platform for exploring the mechanism of brain dynamic deformations. Description of the Drawings

[0035] Figure 1 It is a detection schematic diagram of a mutual inductance type brain deformation array sensor.

[0036] Figure 2 It is a sensing principle diagram of a mutual inductance type brain deformation array sensor.

[0037] Figure 3 It is an imaging schematic diagram of a mutual inductance type brain deformation array sensor.

[0038] Figure 4 It is a photo of a batch-prepared coil unit.

[0039] Figure 5 It is a photo of a four-channel mesh coil array.

[0040] Figure 6 It is a photo of a brain deformation monitoring system for rats.

[0041] Figure 7 The deformation curve of the rat brain tissue under anesthesia state transition detected by a four-channel mesh deformation array sensor.

[0042] Figure 8 The brain tissue deformation imaging of the rat under anesthesia state transition.

[0043] Figure 9 The deformation curve of the rat brain tissue under mechanical impact detected by a four-channel mesh deformation array sensor.

[0044] Figure 10 The brain tissue deformation imaging of the rat after mechanical impact.

[0045] Figure 11 The photos of discrete coil units with different sizes.

[0046] Figure 12 The curves of the displacement response of discrete coil units with different sizes.

[0047] Figure 13 The deformation curve of the rat brain tissue caused by breathing and heartbeat detected by a nine-channel distributed deformation array sensor.

[0048] Figure 14 The brain tissue deformation imaging of the rat caused by breathing and heartbeat.

[0049] Figure 15 The schematic diagrams of the mesh coil array and the distributed coil array. Detailed implementation mode

[0050] Example 1, preparation of a four-channel mesh array sensor and its application in detecting and imaging the deformation of rat brain tissue under anesthesia state transition.

[0051] (1) Preparation of the coil unit. A silicon wafer with a size of 5 cm × 5 cm was marked out. The silicon wafer was treated with oxygen plasma at 150 W for 3 minutes to make it hydrophilic. 0.3 g of dextran was weighed and dissolved in 6 g of deionized water to obtain a sacrificial layer solution. The above-mentioned silicon wafer was placed in a spin coater, 1 mL of the sacrificial layer aqueous solution was dropped onto the center of the silicon wafer, and it was spin-coated at a speed of 2000 revolutions per minute for 15 seconds. After waiting for 5 minutes, it was naturally dried to obtain the sacrificial layer. 0.5 g of parylene precursor was deposited on the silicon wafer modified with the sacrificial layer by chemical vapor deposition to form a substrate insulating layer with a thickness of about 0.5 μm. The coil hollowing pattern was prepared on the mask plate by laser engraving. Each coil had a side length of 1.3 mm, 2 turns, and the interval between coils was 1.5 mm. The mask plate with the coil pattern was pasted on the substrate insulating layer, 20 nm of gold was deposited by thermal evaporation, and after removing the mask plate, a patterned conductive layer was obtained. The turn area between the inside and outside of the conductive coil was formed into an intermediate insulating layer by magnetron sputtering 20 nm of aluminum oxide and annealing. The inside part of the coil was connected to the outside by secondary deposition of 30 nm of gold through the mask plate. 0.8 g of parylene precursor was deposited on the above-mentioned conductive layer by chemical vapor deposition to form a top insulating layer with a thickness of about 0.8 μm. The photo of the batch-prepared coil unit is shown in Figure 4 as shown.

[0052] (2) Preparation of the four-channel mesh deformation array sensor. The coil array arranged in a 2×2 pattern was processed along the outer edge of the coil by laser engraving technology. After including the insulating layer, each coil unit had a side length of 1.5 mm, and the leads faced outward. The single coils were interconnected through the serpentine wire insulating layer to form a complete coil array. The four-channel deformation coil array is shown in Figure 5 as shown.

[0053] (3) Modification of the mesh coil array with an adhesive polydopamine layer. 60 mg of dopamine was weighed and dissolved in 30 mL of Tris-HCl aqueous solution with a volume fraction of 0.1%. It was fully dissolved by the action of a shaker for 3 minutes. The whole silicon wafer was immersed in the above solution for 8 hours, the sacrificial layer was dissolved, and 4 polydopamine layer-modified coil arrays were released. Two coil arrays were placed opposite to each other to construct a four-channel deformation array sensor. The photo of the deformation array sensor implanted in the rat brain equipped with a backend detection device is shown in Figure 6 as shown.

[0054] (4) Detection and imaging of the deformation of rat brain tissue during the transition of the anesthetic state. After disinfection, the rat was fixed on a stereotactic device and anesthetized with isoflurane. The scalp of the rat was cut open with surgical scissors, and the connective tissue was removed. Centered on the bregma, a 5 mm × 5 mm skull was removed with a trephine. A mesh coil array was implanted, and the coil units were adhered to the brain tissue using the adhesive layer formed by polydopamine. Another mesh coil array was fixed to the skull opposite to its center. The lead part of the coil was exposed and connected to the detection module, and the rest was fixed with dental cement. The concentration of isoflurane inhaled by the rat was changed from 2% to 1% (volume ratio of isoflurane to air). The deformation curve detected by the four-channel mesh array sensor during the process is shown in Figure 7 As shown, after the rat reached a stable physiological state at 2% and 1% isoflurane concentrations, the imaging of the deformation of the brain tissue is shown in Figure 8 As shown.

[0055] Example 2: Preparation of a four-channel mesh array sensor and its application in the detection and imaging of the deformation of rat brain tissue under mechanical impact.

[0056] (1) Preparation of a conductive poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid layer and a substrate polydimethylsiloxane insulating layer. A 3 cm × 3 cm silicon wafer was marked out, and the silicon wafer was treated with oxygen plasma at 100 W for 5 minutes to make it hydrophilic. 0.5 g of dextran was weighed and dissolved in 9 g of deionized water to obtain a sacrificial layer solution. The above silicon wafer was placed in a spin coater, 1 ml of the sacrificial layer aqueous solution was dropped onto the center of the silicon wafer, and it was spin-coated at a speed of 3000 rpm for 20 s. After waiting for 5 minutes, it was naturally dried to obtain the sacrificial layer. 0.2 g of polydimethylsiloxane crosslinking agent and 2 g of polydimethylsiloxane matrix were weighed, and 12 g of a mixed solvent of ethyl acetate and hexane with a volume ratio of 1:4 was added, and it was ultrasonically treated for 20 minutes to be fully dissolved to prepare a low-viscosity polydimethylsiloxane solution. The polydimethylsiloxane solution was spin-coated on the silicon wafer modified with the above sacrificial layer at a speed of 5000 rpm for 30 s, and then annealed at 80 °C for 20 minutes to form a substrate polydimethylsiloxane insulating layer. It was treated with oxygen plasma at 100 W for 1 minute to make the insulating layer hydrophilic. A poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid with a thickness of about 1 μm was spin-coated on the substrate insulating layer as the conductive layer.

[0057] (2) Preparation of the mesh coil array. Weigh 3.5 g of polyvinyl alcohol and 46.5 g of deionized water, heat and stir in an oil bath at 80 °C for 5 hours to fully dissolve them, obtaining a polyvinyl alcohol solution with a mass fraction of 7%; under light-shielded conditions, take 15 g of the polyvinyl alcohol solution, add 73.5 mg of diazo to it, and ultrasonically mix for 20 minutes to make it evenly mixed, obtaining a negative photoresist; under light-shielded conditions, spin-coat the negative photoresist on the conductive layer at a speed of 2000 revolutions per minute for 60 seconds, and let it air-dry naturally after 5 minutes; the designed side length of the coil in the lithography pattern is 0.8 mm, the number of turns is 2, and the interval between coils is 1 mm; the exposure dose is 200 mJ / cm². After exposure, develop it with 60 °C deionized water for 2 minutes and then dry it, transferring the pattern to the negative photoresist; use reactive ion etching, with the etching gas being carbon tetrafluoride, the etching pressure being 40 mTorr, the etching power being 150 W, and the etching time being 150 seconds, transferring the negative photoresist pattern to the conductive layer; the turn area between the inside and outside of the conductive coil is insulated with silicone rubber; use poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid to connect the inside part of the coil to the outside; use a spin coater to spin-coat a polydimethylsiloxane solution on the substrate insulating layer and the conductive layer at a speed of 5000 revolutions per minute for 35 seconds, and then anneal it at 70 °C for 30 minutes to form the top insulating layer; use laser engraving technology to process along the outer edge of the coil to obtain a 2×2 arranged coil array. After including the insulating layer, the side length of each coil unit is 1 mm, and the leads face outward; individual coils are interconnected through serpentine wire insulation layers to form a complete coil array.

[0058] (3) Preparation of the mesh deformation array sensor. Weigh 50 mg of dopamine and dissolve it in 20 mL of a 0.1% (volume fraction) Tris-HCl aqueous solution, and fully dissolve it by the action of a shaker for 5 minutes; immerse the whole silicon wafer in the above solution for 8 hours, dissolve the sacrificial layer, and release to obtain 2×2 coil arrays modified with two polydopamine layers; place the two coil arrays opposite to each other to construct a four-channel deformation array sensor.

[0059] (4) Detection and imaging of the deformation of rat brain tissue under mechanical impact. After disinfection, the rat was fixed on a stereotactic device and anesthetized with isoflurane. The scalp of the rat was cut open with surgical scissors, and the connective tissue was removed. With the bregma as the center, a 5 mm × 5 mm skull was removed using a cranial drill. A reticular coil array was implanted. The coil units were adhered to the brain tissue using the adhesive layer formed by polydopamine. Another reticular coil array was centered opposite to it and fixed on the skull. The lead part of the coil was exposed and connected to the detection module, and the rest was fixed with dental cement. In a vertical acrylic tube, a weight of 2 g was released from a height of 10 cm and applied to a 1.5 mm diameter impact pin to transmit a controllable impact to the rat brain tissue. The deformation curve detected by the four-channel deformation array sensor is shown in Figure 9 . The baseline consists of the deformation of the brain tissue caused by breathing and heartbeat. The sharp rising and falling curves show the severe deformation of the brain tissue caused by the impact. The deformation imaging after mechanical impact is shown in Figure 10 , showing the brain tissue deformation imaging corresponding to the maximum peak and trough of the deformation after the impact.

[0060] Example 3: Preparation of a dispersed array sensor and its application in detecting and imaging the deformation of brain tissue caused by heartbeat.

[0061] (1) Preparation of coil units. A 4 cm × 4 cm silicon wafer was marked out and treated with oxygen plasma at 150 W for 3 minutes to make it hydrophilic. 0.3 g of dextran was weighed and dissolved in 5 g of deionized water to obtain a sacrificial layer solution. The above silicon wafer was placed in a spin coater, 1 ml of the sacrificial layer aqueous solution was dropped at the center of the silicon wafer, and it was spin-coated for 8 seconds at a speed of 1500 revolutions per minute. After waiting for 5 minutes, it was naturally dried to obtain the sacrificial layer. 0.5 g of poly(p-xylene) precursor was deposited on the silicon wafer modified with the sacrificial layer by chemical vapor deposition to form a base insulating layer about 0.5 μm thick. Three sizes of coil hollow patterns were prepared on the mask plate by laser engraving. The side lengths of the coils were 1.3 mm, 2.8 mm, and 4.8 mm respectively, and the number of turns was 2 for all. The mask plate with the coil pattern was pasted on the base insulating layer, and 25 nm of gold was deposited by thermal evaporation. After removing the mask plate, a patterned conductive coil layer was obtained. The turn area between the inside and outside of the conductive coil was formed into an intermediate insulating layer by magnetron sputtering 25 nm of aluminum oxide and annealing. The inside part of the coil was connected to the outside by secondary deposition of 30 nm of gold through the mask plate. 0.5 g of poly(p-xylene) precursor was deposited on the above conductive layer by chemical vapor deposition to form a top insulating layer about 0.5 μm thick.

[0062] (2) Fabrication of the distributed array sensor. By processing along the outer edge of the coil using laser engraving technology, 50 discrete coil units were obtained on the silicon wafer. After including the insulating layer, the side lengths of the coil units were 1.5 mm, 3 mm, and 5 mm respectively; 40 mg of dopamine was weighed and dissolved in 15 mL of an aqueous Tris-HCl solution with a volume fraction of 0.1%. It was fully dissolved by the action of a shaker for 5 minutes; the entire silicon wafer was immersed in the above solution for 8 hours, the sacrificial layer was dissolved, and the coil units modified with a polydopamine layer were released; two groups of coil units were placed opposite each other to obtain a distributed array sensor with different coil sizes. Photographs of the coil units with different sizes are shown in Figure 11 as shown, and the responses of coils with different sizes to distance changes are shown in Figure 12 as shown.

[0063] (3) Detection and imaging of the deformation of the rat brain tissue caused by heartbeat and respiration. After disinfection, the rat was fixed on a stereotactic device and anesthetized with isoflurane; the scalp of the rat was cut open with surgical scissors, the connective tissue was removed, and a skull with a size of 7.5 mm × 7.5 mm was removed with a cranial drill centered on the bregma; a 3×3 distributed coil array was implanted, with each coil unit having a side length of 1.5 mm. The coil units were adhered to the brain tissue using the adhesive layer formed by polydopamine. Another 3×3 distributed coil array corresponded one-to-one with the coil units on the cortex and was fixed on the skull; the lead parts of the coils were exposed and connected to the detection module, and the rest were fixed with dental cement; under the anesthetized state, the deformation curves of the rat brain tissue caused by heartbeat and respiration detected by the nine-channel distributed deformation array sensor are shown in Figure 13 as shown, and the deformation imaging is shown in Figure 14 as shown.

Claims

1. A method for preparing a brain deformation array sensor, characterized in that: Using metal or conductive polymer as the conductive material and elastomer or polyparaxylene as the insulating material, a sandwich thin film coil unit of insulating layer-conductive coil-insulating layer is prepared by laser engraving or etching technology; two coil unit arrays construct a deformation array sensor for detecting and imaging dynamic deformation of the brain, which can achieve a time resolution of less than 100 microseconds and a distance resolution of less than 5 microns; The specific steps of preparation are as follows: (1) Spin coating a sacrificial layer on a silicon wafer; spin coating a 10%-70% by mass insulating layer material solution, or chemically vapor depositing polyparaxylene material to form a base insulating layer; (2) transferring the designed conductive coil pattern to the base insulating layer to form a conductive coil layer; (3) performing insulation treatment within the range of the number of coil turns between the inner end and the outer end of the conductive coil layer prepared in step (2) to prevent electrical short circuits between overlapping conductive layers in the coil; (4) connecting the inner end of the conductive coil layer in step (2) to the outside through a conductive material; (5) Spin coating a 10%-70% by mass insulating layer material solution on the patterned coil, or chemically vapor depositing polyparaxylene material to form a top insulating layer; (6) A two-dimensional coil array (M×N) consisting of coil units is obtained on a silicon wafer through laser engraving; (7) immersing the silicon wafer containing the coil array prepared in step (6) in a dopamine solution to dissolve the sacrificial layer in step (1) and release the polydopamine-modified coil array; The sensor consists of two coil arrays and serves as a sensor for continuous and real-time detection of brain deformation.

2. The preparation method according to claim 1, characterized in that: The formation of the conductive coil layer in step (2) includes the following two schemes: (1) depositing a metal material on the base insulating layer by thermal evaporation or magnetron sputtering, and transferring the pattern of the mask to the base insulating layer; or, (2) Spin-coating a conductive polymer solution or depositing a metal material on the base insulating layer, and performing photolithography on the conductive layer using a negative photoresist. The developed photoresist has a coil pattern, and the coil pattern of the photoresist is transferred to the conductive layer by etching.

3. The preparation method according to claim 2, characterized in that: The insulation treatment in step (3) includes sputtering and depositing an aluminum oxide layer and annealing, spin coating an insulation layer material solution with a mass fraction of 10% to 70% or chemical vapor deposition of polyparaxylene material, and patterning; The insulating layer material is selected from polystyrene-butadiene-styrene block copolymer, polydimethylsiloxane, fluororubber, partially hydrogenated polystyrene-butadiene-styrene block copolymer, and polyparaxylene; The conductive material in step (4) is a metal material, or poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, polypyrrole or polythiophene.

4. The preparation method according to claim 3, characterized in that: The laser engraving in step (6) makes the conductive coil layer inside the insulating layer, and the coil units are connected by the insulating material; The dopamine solution in step (7) is obtained by dissolving dopamine in a Tris-HCl aqueous solution, and the ratio of dopamine to the Tris-HCl aqueous solution is ≥ 1.5 mg / ml.

5. The preparation method according to claim 4, characterized in that: The prepared conductive coil layer is a two-dimensional coil array composed of conductive parts in a plurality of coil units.

6. The preparation method according to claim 5, characterized in that: The thickness of the coil unit is ≤5 microns, and the mass density is ≤1.8 g / cubic centimeter; the side length or diameter of the coil unit is 100 microns-5 mm.

7. The preparation method according to claim 6, characterized in that: The deformation array sensor is composed of two groups of coil arrays placed opposite to each other; it is divided into: a dispersed array sensor, that is, each coil array is composed of a number of discrete coil units; a mesh array sensor, that is, each coil array is composed of a number of coils connected to each other through an insulating layer.

8. A brain deformation array sensor obtained by the preparation method of claim 7.

9. Use of the brain deformation array sensor as described in claim 8 in preparing brain tissue deformation detection and imaging devices.

10. The use according to claim 9, characterized in that: For the distributed array sensor, several coil units are placed at different locations of the cortex, and another set of coil units is fixed on the skull at the corresponding location. The detection sites correspond one to one in normal direction. Each sensor detects independently and reads the voltage change of each detection site at the same time, which is converted into deformation change through the voltage-distance correspondence relationship. For mesh array sensors, a mesh coil array is placed on the cortex during implantation, and another mesh coil array is fixed on the skull at the corresponding position. The normals of the detection sites correspond one to one, and each sensor detects independently and reads the voltage changes at each detection site at the same time, which are converted into deformation changes through the voltage-distance correspondence relationship.

Images