An interventional EEG signal acquisition scaffold and its preparation method

Abstract

This invention discloses an interventional EEG signal acquisition scaffold and its fabrication method, belonging to the field of brain-computer interface technology. It comprises a medical-grade nickel-titanium alloy substrate and a five-layer structure sequentially laminated to the substrate surface from the inside out: the first layer is a PECVD silicon dioxide insulating layer; the second layer is a first platinum-iridium alloy conductive layer for forming signal acquisition electrodes; the third layer is an ALD silicon dioxide encapsulation layer; the fourth layer is a second platinum-iridium alloy conductive layer for forming signal lead circuits; and the fifth layer is an ALD pyflon hydrophobic layer. The process involves: S1, substrate treatment; S2, plating lamination; and S3, welding encapsulation. Through the three-dimensional layout of the five-layer functional composite structure with circumferential electrodes and axial leads, spatial separation of electrode acquisition and lead transmission is achieved, resulting in more thorough channel isolation, no signal crosstalk, and improved stability of the scaffold signal acquisition.

Description

Technical Field

[0001] This application relates to the field of brain-computer interface technology, and more specifically, to an interventional EEG signal acquisition scaffold and its preparation method. Background Technology

[0002] Interventional EEG signal acquisition stents are a type of minimally invasive neural interface device implemented via an intravascular interventional approach. They can be implanted into target intracranial vascular regions through minimally invasive interventional surgery, achieving long-term, stable, and high-density acquisition of EEG signals without damaging brain tissue. They have become core components in fields such as precise localization of epileptic foci, intraoperative neurophysiological monitoring, and chronic neuromodulation. These devices use a medical-grade nickel-titanium alloy self-expanding stent as a mechanical carrier, integrating microelectrode arrays, signal conduction pathways, and encapsulation structures. They perform functions such as intravascular adhesion, signal acquisition, and external transmission, combining minimally invasiveness, safety, and functionality. This represents an important research direction at the intersection of biomedical engineering, neuroscience, and interventional medical devices.

[0003] Existing interventional EEG signal acquisition stents generally use a composite structure of a metal stent base, a conductive layer, and an insulating layer to achieve signal acquisition. Electrodes and wires are formed on the surface of the stent by pasting, wrapping, spraying, or simple single-layer coating. EEG signals are directly picked up using the conductive layer. Some stents use a single-layer planar wiring method, placing the electrode unit and lead circuit in the same conductive layer, relying on a single insulating layer to achieve limited isolation, and completing the external lead connection through conventional welding.

[0004] Existing interventional EEG signal acquisition stents consist of a conductive layer and an insulating layer, with a lead wire welded to the conductive layer to transmit brain electrical signals. However, in these existing stents, the solder joints between the lead wire and the conductive layer are often protected by simple wrapping. During the transmission of brain electrical signals, the lead wire generates heat at the solder joint. This heat accumulation can easily cause thermal expansion at the solder joint and exert thermal stress on the wrapping structure. Under the long-term repeated thermal stress of the solder joint, the wrapping structure is prone to loosening at the connection between the solder joint and the conductive layer and the lead wire. This allows cerebrospinal fluid from the brain to seep into the wrapping structure through the loosened area and come into contact with the solder joint. Furthermore, the weakly alkaline environment of the cerebrospinal fluid can easily cause electrochemical corrosion of the solder joint, leading to open circuits in the solder joint area, interrupting brain signal transmission, and seriously affecting the stability of stent signal acquisition.

[0005] In view of this, this application proposes a more stable and safer implantable EEG signal acquisition scaffold. Summary of the Invention

[0006] Technical problem to be solved: The purpose of this application is to provide an interventional EEG signal acquisition scaffold and its preparation method, which solves the technical problem mentioned in the background art above.

[0007] Technical Solution: In one aspect, the technical solution of this application provides an interventional EEG signal acquisition scaffold, comprising a medical nickel-titanium alloy substrate and a five-layer structure sequentially laminated to the surface of the substrate from the inside out: the first layer is a PECVD silicon dioxide insulating layer, the second layer is a first platinum-iridium alloy conductive layer for forming signal acquisition electrodes; the third layer is an ALD silicon dioxide encapsulation layer, the fourth layer is a second platinum-iridium alloy conductive layer for forming signal lead circuits; and the fifth layer is an ALD pyflon hydrophobic layer. The support has several independent electrode units distributed circumferentially. Each electrode unit is composed of the first platinum-iridium alloy conductive layer and forms a thin film conductive channel through the second platinum-iridium alloy conductive layer. The bracket has a micro laser welding point at its tail end. The second platinum-iridium alloy conductive layer converges to the micro laser welding point. The micro laser welding point is covered with a sealing assembly. A developing ring is fixed to the outer wall of the sealing assembly. The micro laser welding point is used to electrically connect with the external lead wire. The sealing assembly is insulated and separated between each micro laser welding point.

[0008] Furthermore, the sealing assembly includes medical silicone covering the outside of the micro laser welding point, a sealing sleeve is fixedly fitted to the outer wall of the medical silicone, a imaging ring is fixedly fitted to the outer wall of the sealing sleeve, and the sealing sleeve includes a lower sealing sleeve and an upper sealing sleeve, which are fitted and fixed to the outer wall of the medical silicone so that the medical silicone is shaped and covers the outside of the micro laser welding point. The sealing assembly also includes a water-absorbing resin plate embedded and fixed to the inner wall of the upper cover. The water-absorbing resin plate is attached to the outer wall of the medical silicone. Multiple sets of suction and testing components are fixed to the bottom surface of the water-absorbing resin plate. The suction and testing components are inserted into the medical silicone and are arranged between each micro laser welding point. The suction and testing components are used to absorb the cerebrospinal fluid that has seeped into the medical silicone and to guide the cerebrospinal fluid into the water-absorbing resin plate, so that the water-absorbing resin plate expands and squeezes the medical silicone.

[0009] Furthermore, the absorbent component includes a water fiber dressing block fixed to the bottom surface of the absorbent resin plate, an elastic silicone block fixed to the side wall of the water fiber dressing block, a first sensing electrode fixed to the top surface of the elastic silicone block, a second sensing electrode fixed to the bottom surface of the elastic silicone block, the first sensing electrode being attached to the bottom surface of the absorbent resin plate, and the second sensing electrode being attached to the top surface of the medical nickel-titanium alloy substrate.

[0010] Furthermore, the thickness of the PECVD silicon dioxide insulating layer and the ALD silicon dioxide encapsulation layer is 0.01±0.001mm, and the thickness of the first platinum-iridium alloy conductive layer and the second platinum-iridium alloy conductive layer is 0.005±0.001mm; the weight percentage content of iridium in the first platinum-iridium alloy conductive layer and the second platinum-iridium alloy conductive layer is 10–20%.

[0011] Furthermore, the electrode unit has 32 channels, and the channel isolation between the electrode units is not less than 85dB at a frequency of 1kHz; The electrode unit and the micro laser welding point at the tail end of the support are electrically connected through a thin film conductive channel formed by the second platinum-iridium alloy conductive layer. The electrode contact impedance of the thin film conductive channel is <5Ω, and the diameter of the micro laser welding point is ≤0.02mm.

[0012] Furthermore, the connecting wire is made of 32 platinum-iridium alloy wires with a diameter of 0.01 mm and 1 stainless steel wire with a diameter of 0.04 mm, and is covered with an insulating layer and a TPU layer in sequence. The overall diameter of the connecting wire is less than 0.3 mm.

[0013] Furthermore, the stent is an intravascular self-expanding structure with a diameter of 4 mm and a length of 18 mm; the medical silicone is doped with nano-silica particles with a particle size of 20 nm to 100 nm and a mass fraction of 1% to 5%.

[0014] Secondly, this application provides a method for preparing an interventional EEG signal acquisition scaffold, used to prepare the scaffold described in the first aspect, comprising the following steps: S1, Substrate treatment; Acid pickling to remove the oxide layer and plasma activation treatment were performed on the medical nickel-titanium alloy substrate. S2, coating composite; S2.1 Deposit a PECVD silicon dioxide insulating layer using PECVD process; S2.2 The first platinum-iridium alloy conductive layer is prepared by magnetron sputtering. S2.3. The first platinum-iridium alloy conductive layer and the PECVD silicon dioxide insulating layer are cut by femtosecond laser to form an electrode pattern; S2.4. ALD silicon dioxide encapsulation layer is deposited sequentially using ALD process, and second platinum-iridium alloy conductive layer is prepared using magnetron sputtering process; femtosecond laser is used to cut the second platinum-iridium alloy conductive layer to form independent thin film conductive channel pattern and pad area; S2.5. ALD hydrophobic layer is coated using ALD process; S3, Welding cladding; Micro-laser welding is performed at the tail end of the support, and the micro-laser welding point is covered with a sealing assembly and the imaging ring is fixed.

[0015] Furthermore, in S2.3, a femtosecond laser is used to perform micron-level cutting of the electrode pattern and the first platinum-iridium alloy conductive layer; After S2.5 and before S3, a femtosecond laser is used to locally remove the hydrophobic layer to expose the pad area.

[0016] Furthermore, the surface of the first platinum-iridium alloy conductive layer is roughened to a nanoscale by argon plasma etching to reduce electrode contact resistance.

[0017] Beneficial effects: One or more technical solutions provided in this application have at least the following technical effects or advantages: 1. Through the three-dimensional layout of the five-layer functional composite structure and circumferential electrodes and axial leads, the electrode acquisition and lead transmission spaces are separated, the channel isolation is more thorough, the signal crosstalk is eliminated, and the stability of the support signal acquisition is improved.

[0018] 2. The micro-laser welding points are covered and separated by the sealing component, and together with the imaging ring, they achieve intraoperative positioning and mechanical reinforcement. Utilizing the double reinforcement structure, the structural strength and durability of the stent welding position are improved, thereby enhancing the safety and service life of the stent.

[0019] 3. By coating the entire surface with an ALD hydrophobic layer, the continuous and dense coating structure avoids the problems of uneven coating and peeling defects in traditional methods, resulting in higher biocompatibility of the stent, lower risk of thrombosis and inflammation, and further improving the safety of stent signal acquisition.

[0020] 4. By setting a composite sealing structure of a shaped sealing sleeve, a water-absorbing resin plate, and a suction and measurement component outside the micro laser welding point, the technical problem of the medical silicone coating on the welding point loosening due to repeated thermal expansion stress at the welding point, resulting in cerebrospinal fluid seeping into and contacting the welding point, causing the welding point to open circuit and fail, is solved. This further improves the safety and reliability of the welding point protection and ensures the safety and stability of the stent signal acquisition.

[0021] 5. The absorbent resin plate, in conjunction with the absorption and detection component, can quickly capture and guide cerebrospinal fluid when the medical silicone ages and breaks or when cerebrospinal fluid seeps in. This causes the absorbent resin plate to expand rapidly, squeezing the medical silicone to achieve mechanical sensing and early warning of encapsulation failure. It also squeezes out and seals the damaged opening by extruding the seeping cerebrospinal fluid and sealing the leakage channel between the upper cover and the medical silicone. This effectively prevents cerebrospinal fluid from reaching the solder joint and causing damage. Structurally, this design enables failure monitoring and alerting, avoiding risks such as short circuits and signal interruptions. It further improves the safety of the solder joint encapsulation and ensures the safety of stent signal acquisition.

[0022] 6. The aspiration and detection components are arranged between each solder joint, which can accurately locate the leakage channel without interfering with electrode acquisition and lead transmission, greatly improving the reliability and clinical safety of long-term implantation of interventional EEG stents.

[0023] 7. The water-fiber dressing block has the characteristics of directional water conduction and non-swelling, which can quickly and stably deliver the trace amount of cerebrospinal fluid to the water-absorbing resin plate, avoiding its own expansion from interfering with the stability of the electrodes and structure.

[0024] 8. The first and second sensing electrodes form a vertical detection pair, which can accurately monitor the expansion state of the absorbent resin plate and the infiltration of cerebrospinal fluid through impedance changes, realize the quantification of electrical signals and alarm, and make the detection more sensitive and accurate.

[0025] 9. Using 10–20% iridium content can improve the chemical stability and conductivity consistency of the material, so that the electrode does not drift or fail in the in vivo environment. The platinum-iridium alloy is ultra-thin and the ratio is optimized, resulting in low electrode impedance and no passivation after long-term implantation, thus improving the stability of stent performance.

[0026] 10. The electrode layer and the lead layer are completely electrically isolated by using double-layer silicon dioxide, which blocks the coupling between channels from the structure. Compared with the traditional single-layer structure, the crosstalk suppression capability is improved, enabling 32-channel synchronous acquisition with channel isolation of ≥85dB. The signal is pure and can capture weak EEG features, thus improving the accuracy of stent signal acquisition.

[0027] 11. A continuous platinum-iridium alloy thin film is used to form a low-resistance path, resulting in a contact impedance of <5Ω for the thin film lead channel. This leads to extremely low signal transmission loss and higher acquisition sensitivity of the stent. The solder joint diameter is ≤0.02mm. The use of micro solder joints reduces the stress area, resulting in less stress on the solder joints and making them less prone to fatigue fracture. This avoids the risk of root fracture caused by vascular pulsation and improves the safety of the stent welding structure.

[0028] 12. The lead wire adopts an external double-layer coating, using the insulation layer and TPU layer to provide electrical isolation and mechanical protection, making the lead wire reliably insulated, resistant to tension, and not prone to wear and short circuits, thus ensuring the reliability of the bracket connection. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of an interventional electroencephalogram (EEG) signal acquisition stent of the present invention.

[0030] Figure 2 This is an exploded view of the overall structure of the present invention.

[0031] Figure 3 This is a schematic diagram of the connection structure between the sealing assembly and the developing ring of the present invention.

[0032] Figure 4 This is a schematic diagram of the sealing assembly structure of the present invention.

[0033] Figure 5 This is a schematic diagram of the lead wire structure of the present invention.

[0034] Figure 6 This is a schematic diagram of the connection structure between the conductor wire and the first platinum-iridium alloy conductive layer and the second platinum-iridium alloy conductive layer of the present invention.

[0035] Figure 7 This is a schematic diagram of the welding structure of the lead wire of the present invention.

[0036] Figure 8 This is a schematic diagram of the five-layer composite structure on the top surface of the medical nickel-titanium alloy substrate of the present invention.

[0037] Figure 9 This is a schematic diagram of the lower and upper cover structures of the present invention.

[0038] Figure 10 for Figure 9 A magnified schematic diagram of the structure at point A in the middle.

[0039] Figure 11 This is a cross-sectional view of the structure of the sealing assembly covering the solder joint of the present invention.

[0040] Figure 12 for Figure 11 A magnified schematic diagram of the structure at point B in the middle.

[0041] Explanation of the numbers in the diagram: 100, Medical nickel-titanium alloy substrate; 200, Imaging ring; 300, Lead wire; 400, Sealing assembly; 410, Medical silicone; 420, Lower cover; 430, Upper cover; 440, Absorbent resin plate; 450, Absorption and measurement component; 451, Water fiber dressing block; 452, First sensing electrode; 453, Elastic silicone block; 454, Second sensing electrode; 500, PECVD silica insulating layer; 600, First platinum-iridium alloy conductive layer; 700, ALD silica encapsulation layer; 800, Second platinum-iridium alloy conductive layer; 900, ALD hydrophobic layer. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0044] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or a link; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0045] Example 1: Refer to Figures 1-7 This application provides an interventional EEG signal acquisition stent, comprising a medical nickel-titanium alloy substrate 100 and a five-layer structure sequentially laminated to the surface of the substrate from the inside out: the first layer is a PECVD silicon dioxide insulating layer 500, the second layer is a first platinum-iridium alloy conductive layer 600, used to form signal acquisition electrodes; the third layer is an ALD silicon dioxide encapsulation layer 700, the fourth layer is a second platinum-iridium alloy conductive layer 800, used to form signal lead circuits; and the fifth layer is an ALD pyflon hydrophobic layer 900. The support has several independent electrode units distributed circumferentially. Each electrode unit is composed of the first platinum-iridium alloy conductive layer 600 and forms a thin film conductive channel through the second platinum-iridium alloy conductive layer 800. The bracket has a micro laser welding point at its tail end. The second platinum-iridium alloy conductive layer 800 is gathered at the micro laser welding point. The micro laser welding point is covered with a sealing component 400. A developing ring 200 is sleeved and fixed on the outer wall of the sealing component 400. The micro laser welding point is used to electrically connect with the external connecting wire 300. The sealing component 400 is insulated and separated between each micro laser welding point. Through the three-dimensional layout of the five-layer functional composite structure and circumferential electrodes and axial leads, the electrode acquisition and lead transmission spaces are separated, the channel isolation is more thorough, the signal is free from crosstalk, and the stability of the support signal acquisition is improved. The micro laser welding points are covered and separated by the sealing component 400, and together with the imaging ring 200, they achieve intraoperative positioning and mechanical reinforcement. With the double reinforcement structure, the structural strength and durability of the stent welding position are improved, thus enhancing the safety and service life of the stent. By coating the entire surface with an ALD Peflon 900 hydrophobic layer, the continuous and dense coating structure avoids the problems of uneven coating and peeling defects in traditional methods, resulting in higher biocompatibility of the stent, lower risk of thrombosis and inflammation, and further improving the safety of stent signal acquisition.

[0046] In this embodiment, the sealing assembly 400 includes a medical silicone 410 covering the outside of the micro laser welding point. A sealing sleeve is fixedly fitted to the outer wall of the medical silicone 410, and a imaging ring 200 is fixedly fitted to the outer wall of the sealing sleeve. The sealing sleeve includes a lower sealing sleeve 420 and an upper sealing sleeve 430. The lower sealing sleeve 420 and the upper sealing sleeve 430 are fitted and fixed to the outer wall of the medical silicone 410 so that the medical silicone 410 is shaped and covers the outside of the micro laser welding point. The sealing assembly 400 also includes a water-absorbing resin plate 440 embedded and fixed to the inner wall of the upper cover 430. The water-absorbing resin plate 440 is attached to the outer wall of the medical silicone 410. Multiple sets of suction and testing components 450 are fixed to the bottom surface of the water-absorbing resin plate 440. The suction and testing components 450 are inserted into the medical silicone 410 and are arranged between each micro laser welding point. The suction and testing components 450 are used to absorb the cerebrospinal fluid that has seeped into the medical silicone 410 and to guide the cerebrospinal fluid into the water-absorbing resin plate 440, so that the water-absorbing resin plate 440 expands and squeezes the medical silicone 410. By setting a composite sealing structure of a shaped sealing sleeve, a water-absorbing resin plate 440, and a suction and measurement component 450 on the outside of the micro laser welding point, the technical problem of the welding point being unable to open due to the loosening of the medical silicone 410 covering the welding point under repeated thermal expansion stress is solved. This leads to the infiltration of cerebrospinal fluid and contact with the welding point, causing the welding point to fail. This further improves the safety and reliability of the welding point protection and ensures the safety and stability of the stent signal acquisition. The sealing sleeve is composed of a lower sealing sleeve 430 and an upper sealing sleeve 430. It is easy to install and can shape and constrain the internal medical silicone 410, so that the medical silicone 410 tightly, evenly and without gaps covers the solder joint, preventing the medical silicone 410 from loosening and significantly improving the stability and sealing of the encapsulation structure. The absorbent resin plate 440 works in conjunction with the absorption and detection component 450 to quickly capture and guide cerebrospinal fluid when the medical silicone 410 ages and breaks or cerebrospinal fluid seeps in. This causes the absorbent resin plate 440 to expand rapidly. By expanding and squeezing the medical silicone 410, it achieves mechanical sensing and early warning of encapsulation failure. It also squeezes out the seeped cerebrospinal fluid and squeezes to seal the damaged opening, and seals the leakage channel between the upper cover 430 and the medical silicone 410. This effectively prevents cerebrospinal fluid from reaching the solder joint and causing damage. Structurally, it enables failure monitoring and prompting, avoids risks such as short circuits and signal interruptions, further improves the safety of the solder joint encapsulation, and ensures the safety of stent signal acquisition. The aspiration and detection component 450 is arranged between each solder point, which can accurately locate the leakage channel without interfering with electrode acquisition and lead transmission, greatly improving the reliability and clinical safety of long-term implantation of interventional EEG stents.

[0047] In this embodiment, the absorbent component 450 includes a water fiber dressing block 451 fixed to the bottom surface of the absorbent resin plate 440, an elastic silicone block 453 fixed to the side wall of the water fiber dressing block 451, a first sensing electrode 452 fixed to the top surface of the elastic silicone block 453, a second sensing electrode 454 fixed to the bottom surface of the elastic silicone block 453, the first sensing electrode 452 being attached to the bottom surface of the absorbent resin plate 440, and the second sensing electrode 454 being attached to the top surface of the medical nickel-titanium alloy substrate 100. The water fiber dressing block 451 has the characteristics of directional water conduction and non-expansion, which can quickly and stably deliver the trace amount of cerebrospinal fluid to the water-absorbing resin plate 440, avoiding its own expansion from interfering with the stability of the electrodes and structure. The first sensing electrode 452 and the second sensing electrode 454 form a vertical detection pair, which can accurately monitor the expansion state of the absorbent resin plate 440 and the infiltration of cerebrospinal fluid through impedance changes, realize the quantification alarm of electrical signals, and make the detection more sensitive and accurate.

[0048] In this embodiment, the thickness of both the PECVD silicon dioxide insulating layer 500 and the ALD silicon dioxide encapsulation layer 700 is 0.01±0.001mm, and the thickness of both the first platinum-iridium alloy conductive layer 600 and the second platinum-iridium alloy conductive layer 800 is 0.005±0.001mm; the weight percentage content of iridium in both the first platinum-iridium alloy conductive layer 600 and the second platinum-iridium alloy conductive layer 800 is 10–20%. The thickness of each layer is strictly controlled within the micron-level tolerance, resulting in uniform thickness of the double-layer silica, no pinholes or weak points, consistent insulation strength, and improved electrical performance stability. Using 10–20% iridium content can improve the chemical stability and conductivity consistency of the material, so that the electrode does not drift or fail in the in vivo environment. The platinum-iridium alloy is ultra-thin and the ratio is optimized, resulting in low electrode impedance and no passivation after long-term implantation, thus improving the stability of the stent performance.

[0049] In this embodiment, the electrode unit has 32 channels, and the channel isolation between the electrode units is not less than 85dB at a frequency of 1kHz. The electrode layer and the lead layer are completely electrically isolated by using double-layer silicon dioxide, which structurally blocks the coupling between channels. Compared with the traditional single-layer structure, the crosstalk suppression capability is improved, and 32 channels can be synchronously acquired with a channel isolation of ≥85dB. The signal is pure and can capture weak EEG features, thus improving the signal acquisition accuracy of the stent.

[0050] In this embodiment, the electrode unit and the micro-laser welding point at the tail end of the stent are electrically connected through a thin-film lead channel formed by the second platinum-iridium alloy conductive layer 800. The electrode contact impedance of the thin-film lead channel is <5Ω, and the diameter of the micro-laser welding point is ≤0.02mm. The use of a continuous platinum-iridium alloy thin film to form a low-resistance path results in a contact impedance of <5Ω for the thin-film lead channel, thereby making the signal transmission loss of the stent extremely low and the acquisition sensitivity higher. The welding point diameter is ≤0.02mm. The use of micro-welding points reduces the stress area, resulting in less stress on the welding point and making it less prone to fatigue fracture. This avoids the risk of root fracture caused by vascular pulsation and improves the safety of the stent welding structure.

[0051] In this embodiment, the lead wire 300 is composed of 32 platinum-iridium alloy wires with a diameter of 0.01 mm and 1 stainless steel wire with a diameter of 0.04 mm, twisted together. It is then covered with an insulating layer and a TPU layer, resulting in an overall diameter of less than 0.3 mm. The use of a composite structure of 32 ultra-fine platinum-iridium wires and a single stainless steel reinforcing wire, along with an overall diameter of less than 0.3 mm, makes the intervention more minimally invasive and improves vascular compatibility. The lead wire 300 employs a double-layer outer covering, utilizing an insulating layer and a TPU layer to provide electrical isolation and mechanical protection. This ensures reliable insulation, tensile strength, and resistance to wear and short circuits, guaranteeing the reliability of the stent connection.

[0052] In this embodiment, the stent is an intravascular self-expanding structure with a diameter of 4 mm and a length of 18 mm; the medical-grade silicone 410 is doped with nano-silica particles, the particle size of which is 20 nm to 100 nm and the mass fraction is 1% to 5%. The stent adopts a 4mm×18mm self-expanding structure. Utilizing the self-expanding properties of nickel-titanium alloy, it can automatically adapt to the inner diameter of the blood vessel, ensuring smooth release, uniform adhesion to the wall, and stable electrode contact. This guarantees that the electrode and the blood vessel wall are fully in contact, improving the stability of signal acquisition. Nano-silica is mixed into the micropores of medical silicone 410 to improve the density and volume resistivity of silicone, reduce the probability of leakage, increase the breakdown field strength, and enhance the electrical isolation between channels. Its insulation performance is better than that of pure silicone, thus improving the isolation effect of solder joints from the material level. Nano-silica, as a reinforcing filler, improves the tensile strength, tear resistance, and bending resistance of silicone, making the solder joint coating less prone to detachment under long-term vascular pulsation and stent deformation.

[0053] Example 2: This application provides a method for preparing an interventional EEG signal acquisition scaffold, used to prepare the scaffold described in Example 1, comprising the following steps: S1, Substrate treatment; The medical nickel-titanium alloy substrate 100 is subjected to pickling to remove the oxide layer and plasma activation treatment; S2, coating composite; S2.1. A PECVD silicon dioxide insulating layer of 500 mm is deposited using the PECVD process. S2.2. The first platinum-iridium alloy conductive layer 600 is prepared by magnetron sputtering. S2.3. The first platinum-iridium alloy conductive layer 600 and the PECVD silicon dioxide insulating layer 500 are cut by femtosecond laser to form an electrode pattern; S2.4. ALD silicon dioxide encapsulation layer 700 is deposited sequentially using ALD process, and second platinum-iridium alloy conductive layer 800 is prepared by magnetron sputtering process; second platinum-iridium alloy conductive layer 800 is cut by femtosecond laser to form independent thin film conductive channel pattern and pad area. S2.5, ALD hydrophobic layer 900 is coated using ALD process; S3, Welding cladding; Micro-laser welding is performed at the tail end of the support, and the micro-laser welding point is covered with sealing component 400 and the developing ring 200 is fixed. The entire process employs micro-nano manufacturing technology and standardized procedures such as substrate activation, multi-layer coating, laser patterning, and welding coating, resulting in high batch consistency, mass production capability, and stable performance.

[0054] In this embodiment, in S2.3, a femtosecond laser is used to perform micron-level cutting of the electrode pattern and the first platinum-iridium alloy conductive layer 600; After S2.5 and before S3, a femtosecond laser is used to locally remove the hydrophobic layer to expose the pad area; By employing femtosecond lasers to achieve micron-level cutting of electrodes and channels, the extremely short laser action time prevents thermal accumulation damage to the thin film, resulting in smooth edges, no thermal damage, and no short circuits, thus ensuring the efficiency and effectiveness of the support processing. By locally removing the coating with femtosecond lasers without damaging the underlying conductive layer, precise windowing of the hydrophobic layer is achieved, resulting in accurate pad exposure and higher welding yield.

[0055] In this embodiment, the surface of the first platinum-iridium alloy conductive layer 600 is roughened to a nanoscale by argon plasma etching to reduce the electrode contact impedance. The nanoscale rough surface achieved by argon plasma etching increases the effective contact area between the electrode and the tissue interface, improves the electrical coupling efficiency, further reduces the electrode contact impedance, strengthens signal pickup, and further improves the stability and accuracy of stent signal acquisition.

[0056] In this embodiment, the pad area of ​​the micro laser welding point adopts a serpentine or corrugated structure to adapt to the self-expansion deformation of the support and maintain stable electrical connection. The serpentine or corrugated structure of the pad can be stretched and relaxed to release stress and avoid stress concentration. It can expand and deform with the support without breaking the circuit or delamination, eliminating the risk of weld point breakage from the structural root and significantly improving the reliability of the support for long-term use.

[0057] Specifically, according to Figures 1-7 As shown, the scaffold was prepared according to the following method: S1, Substrate treatment; Medical nickel-titanium alloy self-expanding stents were selected as the substrate. First, the stents were immersed in a mixed pickling solution to remove the surface oxide layer, oil and impurities. They were then rinsed repeatedly with deionized water and vacuum dried. Subsequently, the substrates were placed in a plasma activation device and surface activation was performed using argon as the working gas to improve the bonding strength between the coating and the substrate and prevent the coating from peeling off in the future. S2, coating composite; S2.1. Using plasma-enhanced chemical vapor deposition (PECVD) process, a PECVD silicon dioxide insulating layer 500 is uniformly deposited on the surface of the activated nickel-titanium alloy substrate. The deposition temperature is controlled at 120℃ and the deposition thickness is 0.01mm, forming a dense, uniform, and pinhole-free base insulating layer to achieve electrical isolation between the metal substrate and the upper electrode structure. S2.2. A first platinum-iridium alloy conductive layer 600 is deposited on the surface of the PECVD silicon dioxide insulating layer 500 using magnetron sputtering. The sputtering power is 80W, the deposition is carried out in an argon atmosphere, and the thickness is controlled to be 0.005mm. The weight percentage of iridium in the platinum-iridium alloy is 10%. After deposition, the electrode layer surface is etched by argon plasma to achieve nanoscale roughening treatment and reduce electrode contact resistance. S2.3. A femtosecond laser is used to perform micron-level high-precision cutting on the first platinum-iridium alloy conductive layer 600 and the PECVD silicon dioxide insulating layer 500 below it, and 32 independent electrode unit patterns are formed according to the preset layout to ensure that the electrode size is consistent, the edges are neat, there is no thermal damage, and there is no short circuit residue. S2.4. Using atomic layer deposition (ALD) technology, an ALD silicon dioxide encapsulation layer 700 with a thickness of 0.01 mm is deposited above the electrode layer to achieve complete electrical isolation between the electrode layer and the conduction layer and suppress crosstalk between channels. Continuing with the magnetron sputtering process, a second platinum-iridium alloy conductive layer 800 with a thickness of 0.005 mm and an iridium content of 10% was deposited above the ALD silicon dioxide encapsulation layer 700. The second platinum-iridium alloy conductive layer 800 was cut again using a femtosecond laser to form an independent axial conductive channel pattern and pad area; S2.5. Using atomic layer deposition (ALD) technology, an ALD hydrophobic layer 900 is coated on the outer surface of the entire stent to form a continuous, uniform, and defect-free bioprotective coating, achieving waterproofing, protection against cerebrospinal fluid erosion, inhibition of protein adsorption, and reduction of the risk of thrombosis and inflammatory response. S3, Welding cladding; Micro-laser welding is performed on the pad area at the tail end of the stent to precisely connect the external lead wire 300 to the pad area, forming a stable electrical connection. After welding, medical silicone 410 is uniformly wrapped around each weld point, which separates the weld points and achieves a triple function of insulation, sealing, and stress buffering. A sealing sleeve is then encapsulated, and multiple sets of suction and detection components 450 are inserted into the medical silicone 410 and placed between two adjacent micro-laser welding points to accurately monitor the welding position. At the same time, a contrast ring 200 is fixed at the tail end of the stent and fitted onto the outer wall of the sealing sleeve for intraoperative image positioning and to further enhance the mechanical stability of the weld point area, thus completing the stent fabrication.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An interventional EEG signal acquisition stent, characterized in that: It includes a medical nickel-titanium alloy substrate (100) and a five-layer structure sequentially laminated to the surface of the substrate from the inside out: the first layer is a PECVD silicon dioxide insulating layer (500), the second layer is a first platinum-iridium alloy conductive layer (600) used to form signal acquisition electrodes; the third layer is an ALD silicon dioxide encapsulation layer (700), the fourth layer is a second platinum-iridium alloy conductive layer (800) used to form signal lead circuits; and the fifth layer is an ALD pyrrolidone hydrophobic layer (900). The support has several independent electrode units distributed circumferentially. Each electrode unit is composed of the first platinum-iridium alloy conductive layer (600) and forms a thin film conductive channel through the second platinum-iridium alloy conductive layer (800). The bracket has a micro laser welding point at its tail end. The second platinum-iridium alloy conductive layer (800) converges to the micro laser welding point. The micro laser welding point is covered with a sealing assembly (400). A developing ring (200) is sleeved and fixed on the outer wall of the sealing assembly. The micro laser welding point is used to electrically connect with the external lead wire (300). The sealing assembly (400) is insulated and separated between each micro laser welding point.

2. The interventional EEG signal acquisition stent according to claim 1, characterized in that: The sealing assembly (400) includes medical silicone (410) covering the outside of the micro laser welding point. A sealing sleeve is fixedly fitted to the outer wall of the medical silicone (410). A imaging ring (200) is fixedly fitted to the outer wall of the sealing sleeve. The sealing sleeve includes a lower sealing sleeve (420) and an upper sealing sleeve (430). The lower sealing sleeve (420) and the upper sealing sleeve (430) are fitted and fixed to the outer wall of the medical silicone (410) so that the medical silicone (410) is shaped and covers the outside of the micro laser welding point. The sealing assembly (400) also includes a water-absorbing resin plate (440) embedded and fixed to the inner wall of the upper cover (430). The water-absorbing resin plate (440) is attached to the outer wall of the medical silicone (410). Multiple sets of suction and testing components (450) are fixed on the bottom surface of the water-absorbing resin plate (440). The suction and testing components (450) are inserted into the medical silicone (410) and are arranged between each micro laser welding point. The suction and testing components (450) are used to absorb the cerebrospinal fluid that has seeped into the medical silicone (410) and to guide the cerebrospinal fluid into the water-absorbing resin plate (440) so that the water-absorbing resin plate (440) expands and squeezes the medical silicone (410).

3. The interventional EEG signal acquisition stent according to claim 2, characterized in that: The absorbent component (450) includes a water fiber dressing block (451) fixed to the bottom surface of the absorbent resin plate (440), an elastic silicone block (453) fixed to the side wall of the water fiber dressing block (451), a first sensing electrode (452) fixed to the top surface of the elastic silicone block (453), and a second sensing electrode (454) fixed to the bottom surface of the elastic silicone block (453). The first sensing electrode (452) is attached to the bottom surface of the absorbent resin plate (440), and the second sensing electrode (454) is attached to the top surface of the medical nickel-titanium alloy substrate (100).

4. The interventional EEG signal acquisition stent according to claim 1, characterized in that: The thickness of the PECVD silicon dioxide insulating layer (500) and the ALD silicon dioxide encapsulation layer (700) is 0.01±0.001mm, and the thickness of the first platinum-iridium alloy conductive layer (600) and the second platinum-iridium alloy conductive layer (800) is 0.005±0.001mm; the weight percentage content of iridium in the first platinum-iridium alloy conductive layer (600) and the second platinum-iridium alloy conductive layer (800) is 10–20%.

5. The interventional EEG signal acquisition stent according to claim 1, characterized in that: The electrode unit has 32 channels, and the channel isolation between the electrode units is not less than 85dB at a frequency of 1kHz. The electrode unit and the micro laser welding point at the tail end of the support are electrically connected through a thin film conductive channel formed by the second platinum-iridium alloy conductive layer (800). The electrode contact impedance of the thin film conductive channel is <5Ω and the diameter of the micro laser welding point is ≤0.02mm.

6. The interventional EEG signal acquisition stent according to claim 5, characterized in that: The lead wire (300) is made of 32 platinum-iridium alloy wires with a diameter of 0.01 mm and 1 stainless steel wire with a diameter of 0.04 mm, and is covered with an insulating layer and a TPU layer in sequence. The overall diameter of the lead wire (300) is less than 0.3 mm.

7. The interventional EEG signal acquisition stent according to claim 2, characterized in that: The stent is an intravascular self-expanding structure with a diameter of 4 mm and a length of 18 mm; the medical silicone (410) is doped with nano-silica particles with a particle size of 20 nm to 100 nm and a mass fraction of 1% to 5%.

8. A method for preparing an interventional EEG signal acquisition scaffold, characterized in that: The preparation of the stent according to any one of claims 1-7 includes the following steps: S1, Substrate treatment; The medical nickel-titanium alloy substrate (100) was subjected to pickling to remove the oxide layer and plasma activation treatment; S2, coating composite; S2.1 Deposit a PECVD silicon dioxide insulating layer (500) using the PECVD process. S2.

2. The first platinum-iridium alloy conductive layer (600) is prepared by magnetron sputtering. S2.

3. The first platinum-iridium alloy conductive layer (600) and the PECVD silicon dioxide insulating layer (500) are cut by femtosecond laser to form an electrode pattern. S2.

4. The ALD silicon dioxide encapsulation layer (700) is deposited sequentially by ALD process and the second platinum-iridium alloy conductive layer (800) is prepared by magnetron sputtering. The second platinum-iridium alloy conductive layer (800) is cut by femtosecond laser to form an independent thin-film conductive channel pattern and pad area. S2.

5. ALD hydrophobic layer (900) is coated using ALD process. S3, Welding cladding; Micro-laser welding is performed at the tail end of the support, and the micro-laser welding point is covered with a sealing assembly (400) and the developing ring (200) is fixed.

9. The method for preparing an interventional EEG signal acquisition scaffold according to claim 8, characterized in that: In S2.3, a femtosecond laser is used to perform micron-level cutting of the electrode pattern and the first platinum-iridium alloy conductive layer (600); After S2.5 and before S3, a femtosecond laser is used to locally remove the hydrophobic layer to expose the pad area.

10. The method for preparing an interventional EEG signal acquisition scaffold according to claim 9, characterized in that: The surface of the first platinum-iridium alloy conductive layer (600) is roughened to nanoscale by argon plasma etching in order to reduce the electrode contact impedance.

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