Negative Poisson's ratio intelligent intravascular stent based on piezoelectric biological material and preparation method of negative Poisson's ratio intelligent intravascular stent

Abstract

The invention belongs to the technical field of medical instruments, and particularly relates to a negative Poisson's ratio intelligent intravascular stent based on piezoelectric biological materials and a preparation method of the negative Poisson's ratio intelligent intravascular stent. The intelligent intravascular stent has a negative Poisson's ratio structure; the functionalized stent wire comprises a core electrode layer, a piezoelectric functional layer, a shielding electrode layer and a packaging layer which are sequentially stacked from inside to outside. A core electrode lead is embedded in the core electrode layer, and a shielding electrode lead is embedded in the shielding electrode layer; the functional stent wire is made of a bioabsorbable material or a biodegradable material; and the piezoelectric functional layer adopts a high-molecular polymer with an oriented polar group, and constructs and forms a piezoelectric active structure with ordered orientation. Compared with the prior art, the problem that an existing intravascular stent is single in function is solved. According to the scheme, dynamic monitoring, active repairing and biocompatibility are integrated, and an innovative solution is provided for treatment of cardiovascular diseases and monitoring of blood vessel health.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, specifically relating to a negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials and its preparation method. Background Technology

[0002] Cardiovascular disease is one of the leading causes of death worldwide, with vascular stenosis and occlusion being common pathological manifestations. Vascular stents, as an important interventional treatment device, are widely used to restore vascular patency. However, traditional metallic stents have several limitations: First, their rigid structure easily leads to damage to the vascular intima, causing in-stent restenosis; second, the permanent presence of metallic stents in the body may cause long-term inflammatory responses, thrombosis, and abnormal vascular wall remodeling; furthermore, traditional stents lack the function of monitoring vascular status, making it impossible to understand changes in vascular pressure and tissue repair in real time.

[0003] In recent years, biodegradable scaffolds have become a research hotspot, as they can gradually degrade after fulfilling their supporting function, avoiding the risks of long-term implantation. For example, poly-L-lactic acid scaffolds have been used clinically, but their function is singular and cannot achieve integrated monitoring and treatment. Meanwhile, negative Poisson's ratio structures have been introduced into scaffold design, allowing them to expand both laterally and longitudinally under stress, better matching the biomechanical behavior of blood vessels and reducing irritation to the vessel walls.

[0004] Chinese patent CN109893295A discloses a negative Poisson's ratio biodegradable vascular stent structure. This stent structure is designed based on the special properties of biodegradable materials and exhibits a negative Poisson's ratio effect. After implantation, the biodegradable vascular stent with this structure can match the negative Poisson's ratio effect of the vascular intima, thereby reducing stent damage to the vascular tissue and lowering the probability of in-stent restenosis. Chinese patent CN106236338A discloses an additive manufacturing method for a negative Poisson's ratio biodegradable shape memory polymer vascular stent. However, these stents only serve to support the vascular wall and cannot actively promote vascular wall repair. Furthermore, the lack of sensors makes monitoring the working status of the vascular stent difficult.

[0005] Chinese patent CN111513900B discloses a negative Poisson's ratio biodegradable vascular stent structure based on a wave configuration. This structure ensures uniform stress distribution during stent deployment, solving the problem of uneven degradation caused by stress concentration during degradation of biodegradable stents, and its tensile properties enable precise stent positioning. However, this structure requires nested ring structures of different sizes, resulting in a complex fabrication process; the structure is made of magnesium alloy, which is costly and cannot meet the requirements for short-term use and rapid degradation.

[0006] Chinese patent CN119257809A discloses an ultra-flexible electronic device that can be integrated into a vascular stent and its application. It includes a self-expanding vascular stent, a flexible substrate and electrodes sequentially stacked on the surface of the self-expanding vascular stent; the self-expanding vascular stent has a mesh structure; the flexible substrate has a mesh structure and covers a portion of the mesh wire surface; the electrodes are located on the surface of the flexible substrate. However, this solution has the following drawbacks: 1) The flexible substrate in this solution is made of polyimide, which is a non-degradable polymer material and cannot be naturally degraded in the human body. This means that after the electronic device completes its diagnostic and treatment mission, it must be removed from the body through a second surgery, which not only increases the patient's medical trauma, pain, and economic burden, but may also lead to postoperative complications such as infection and vascular damage; 2) Both the self-expanding vascular stent and the flexible substrate of this device adopt a traditional rhomboid mesh structure design, while the inner wall tissue of human blood vessels has a typical negative Poisson's ratio effect. The mechanical properties of the traditional rhomboid mesh structure do not match the negative Poisson's ratio effect of the vascular wall, which can easily lead to poor adhesion between the device and the vascular wall after implantation. It may even cause relative friction due to vascular contraction and relaxation, resulting in damage to the vascular wall. It will also affect the accuracy and stability of the monitoring data. 3) The flexible electrode in this scheme only has the function of passively monitoring the physiological state of blood vessels and cannot realize active electrical stimulation therapy on diseased blood vessel sites, thus limiting its application scenarios. Summary of the Invention

[0007] The purpose of this invention is to address at least one of the aforementioned problems by providing a negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials and its fabrication method, thereby overcoming the limitation of single-function vascular stents in existing technologies. This solution integrates dynamic monitoring, active repair, and biocompatibility, providing an innovative solution for the treatment of cardiovascular diseases and the monitoring of vascular health.

[0008] The objective of this invention is achieved through the following technical solution: The first aspect of this invention discloses a negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials, comprising functionalized stent wires; The aforementioned intelligent vascular stent has a negative Poisson's ratio structure; The functionalized support wire includes a core electrode layer, a piezoelectric functional layer, a shielding electrode layer, and an encapsulation layer stacked sequentially from the inside out; a core electrode lead is embedded in the core electrode layer, and a shielding electrode lead is embedded in the shielding electrode layer; Each layer of the functionalized scaffold wire is made of bio-absorbable or biodegradable material; among them, the piezoelectric functional layer is made of a polymer with oriented polar groups and is constructed to form an oriented, ordered piezoelectric active structure.

[0009] Preferably, the negative Poisson's ratio smart vascular stent further includes a stent body, and the functionalized stent wire is wrapped around the outside of the stent body; The scaffold body is made of polylactic acid, silk fibroin, or polylactic acid / polycaprolactone composite material.

[0010] Preferably, the functionalized stent wire is wrapped around the outer surface of the stent body with a negative Poisson's ratio structure, and the smart vascular stent has a negative Poisson's ratio structure based on the negative Poisson's ratio structure of the stent body. The negative Poisson's ratio structure is one or more of the following: concave structure, double arrowhead structure, and curved concave honeycomb structure.

[0011] Preferably, the functionalized stent wire has a negative Poisson's ratio structure, and the smart vascular stent has a negative Poisson's ratio structure based on the negative Poisson's ratio structure of the functionalized stent wire. The negative Poisson's ratio structure is one or more of the following: concave structure, double arrowhead structure, and curved concave honeycomb structure.

[0012] Preferably, the core electrode layer, the shielding electrode layer, the core electrode lead, and the shielding electrode lead are each made of a bio-absorbable metallic conductive material or a conductive polymer composite material.

[0013] Preferably, the piezoelectric functional layer is made of polarized poly-L-lactic acid, chitosan, etc. β - Glycine or collagen.

[0014] Preferably, the encapsulation layer is made of biodegradable silicone, porcine fibrin adhesive, or polyethylene glycol hydrogel.

[0015] Preferably, the negative Poisson's ratio smart vascular stent is connected to an external signal processing platform via a core electrode lead and a shielding electrode lead.

[0016] A second aspect of this invention discloses a method for preparing a negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials as described above, comprising the following steps: S1: The core electrode layer is prepared by laser cutting and wire drawing, and the core electrode leads are led out by ultrasonic welding or adhesive bonding. S2: The precursor of the piezoelectric functional layer is loaded on the outside of the core electrode layer by electrospinning or dip-coating, and then the piezoelectric functional layer is prepared by freeze drying, heat setting and polarization treatment. S3: A shielding electrode layer is prepared on the outside of the piezoelectric functional layer by magnetron sputtering, solution coating or electrospinning, and the shielding electrode leads are led out by ultrasonic welding or adhesive bonding. S4: An encapsulation layer is prepared on the outside of the shielding electrode layer by microfluidic coating or impregnation coating to form a functionalized scaffold filament; S5: The functionalized stent wires are arranged along the auxiliary device with negative Poisson's ratio structure patterns engraved on the surface, and the negative Poisson's ratio smart vascular stent is formed by laser welding, hot melt bonding or braiding molding process.

[0017] A third aspect of this invention discloses a method for preparing a negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials as described above, comprising the following steps: S1: Prepare a scaffold body with a negative Poisson's ratio structure by photopolymerization 3D printing or fused deposition modeling process; S2: A uniform and continuous core electrode layer is formed on the surface of the support body through solution coating, magnetron sputtering or electrospinning, and the core electrode leads are led out by ultrasonic welding or adhesive bonding. S3: The precursor of the piezoelectric functional layer is loaded on the outside of the core electrode layer by electrospinning or dip-coating, and then the piezoelectric functional layer is prepared by heat setting and polarization treatment. S4: A shielding electrode layer is prepared on the outside of the piezoelectric functional layer by solution dipping or magnetron sputtering, and the shielding electrode leads are led out by ultrasonic welding or adhesive bonding. S5: An encapsulation layer is prepared on the outside of the shielding electrode layer by microfluidic coating or impregnation coating method to form the negative Poisson's ratio smart vascular stent.

[0018] In the above, the core electrode layer, the shielding electrode layer, the core electrode lead, and the shielding electrode lead are each made of bio-absorbable metallic conductive material or conductive polymer composite material.

[0019] The working principle of this invention is as follows: (1) The negative Poisson's ratio structure of the smart vascular stent allows it to expand laterally when it is compressed in the blood vessel, which can better fit the blood vessel wall and reduce local stress concentration, thereby reducing the risk of restenosis.

[0020] (2) The core functional layer of the smart vascular stent uses a biodegradable material that combines biocompatibility and piezoelectric effect. Its working mechanism is mainly based on the positive piezoelectric effect. Under the mechanical stimulation generated by vascular physiological activities (such as blood flow and vasoconstriction), the internal charge of the material will be redistributed and generate a detectable electrical signal. This signal can not only provide real-time feedback on changes in the vascular mechanical environment, but also simulate the endogenous bioelectric microenvironment of the human body, regulate the biological behaviors such as proliferation and migration of vascular endothelial cells, and thus realize the dual functions of vascular status monitoring and active repair.

[0021] (3) Both the core electrode layer and the shielding electrode layer of the intelligent vascular stent are made of bio-absorbable materials. These materials not only ensure the stable conductivity of the electrodes and meet the requirements of stent electrical signal transmission, but also can be gradually degraded through in vivo metabolism and hydrolysis. The degradation products are non-toxic and harmless, and can be completely absorbed and utilized by the organism without causing long-term adverse effects on the body.

[0022] (4) The encapsulation layer of the smart vascular stent is made of biodegradable material that is both biocompatible and low immunogenic, which reduces the stimulation of the vascular wall after implantation while maintaining the stability of the vascular stent. Furthermore, the encapsulation layer can be gradually degraded and excreted in the body, so the service life of the stent can be controlled by changing its thickness.

[0023] Compared with the prior art, the present invention has the following beneficial effects: 1. Biodegradability and biocompatibility: All layers and structures of the intelligent vascular stent are made of biodegradable and bioabsorbable materials, which can effectively avoid the potential risks caused by long-term implantation and significantly reduce the body's immune rejection response.

[0024] 2. Real-time monitoring capability: Based on the positive piezoelectric effect of the piezoelectric functional layer constructed from piezoelectric biomaterials, it can continuously and accurately monitor the dynamic changes in intravascular pressure, providing reliable data support for the clinical management and prognostic assessment of vascular-related diseases.

[0025] 3. Excellent mechanical fit: The negative Poisson's ratio structure used in the intelligent vascular stent can significantly improve the dynamic fit with the blood vessel wall and reduce the risk of mechanical damage to blood vessels caused by mechanical mismatch.

[0026] 4. Potential for personalized medicine: Based on the patient's vascular anatomy, physiological characteristics, and repair needs, the structural parameters (such as size, porosity, and negative Poisson's ratio) and core performance (such as degradation cycle and conductivity) of the stent can be precisely customized to achieve a precise fit for the individual patient.

[0027] 5. Self-powered sensing: It does not rely on an external power source and can achieve autonomous energy supply by triggering the piezoelectric effect through physiological deformation of the blood vessel wall, ensuring the continuous and stable operation of the constructed piezoelectric sensor. Attached Figure Description

[0028] Figure 1 A schematic diagram of a concave-structured negative Poisson's ratio smart support. Figure 2 A schematic diagram of a negative Poisson's ratio smart support with a double-arrow-shaped structure; Figure 3 A schematic diagram of a negative Poisson's ratio smart support with a curved concave honeycomb structure; Figure 4This is a cross-sectional schematic diagram and a partially enlarged structural schematic diagram of the negative Poisson's ratio smart support in Example 1; Figure 5 This is a cross-sectional schematic diagram and a partially enlarged structural schematic diagram of the negative Poisson's ratio smart support in Example 2; In the figure: 1-Support body; 2-Core electrode layer; 3-Core electrode lead; 4-Piezoelectric functional layer; 5-Shielding electrode layer; 6-Shielding electrode lead; 7-Encapsulation layer. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0030] The purpose of this invention is to provide a negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials, its preparation method and application, in order to overcome the shortcomings of traditional vascular stents, such as single function, non-degradability, and lack of monitoring and treatment capabilities.

[0031] This negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials specifically comprises a stent body 1, a bioabsorbable core electrode layer 2, a bioabsorbable core electrode lead 3, a piezoelectric functional layer 4 of piezoelectric biomaterials, a bioabsorbable shielding electrode layer 5, a bioabsorbable shielding electrode lead 6, and a biodegradable encapsulation layer 7. The smart vascular stent has a negative Poisson's ratio structure, with the core electrode layer 2, piezoelectric functional layer 4, shielding electrode layer 5, and encapsulation layer 7 sequentially stacked to form functionalized stent wires loaded on the surface of the stent body 1. The core electrode lead 3 is embedded within the core electrode layer 2, and the shielding electrode lead 6 is embedded within the shielding electrode layer 5. Both the core electrode lead 3 and the shielding electrode lead 6 are electrically connected to an external signal processing platform.

[0032] The stent body 1 is made of a biodegradable polymer or a bioabsorbable conductive material, serving as the core support structure of the device to ensure mechanical stability. The core electrode layer 2 is made of a bioabsorbable conductive material and is used to collect the electrical output signal generated by the piezoelectric functional layer 4 under biomechanical stimulation. The core electrode lead 3 is made of a bioabsorbable conductive material and is used to conduct electrical signals. The piezoelectric functional layer 4 is a polymer with oriented polar groups, which is applied to the surface of the core electrode layer 2 through electrospinning or direct coating to respond to vascular physiological activities (such as blood flow flushing, vascular periodicity). The mechanical stimulation generated by the contraction and relaxation of the core electrode 2 is converted into a stable and detectable electrical signal through the positive piezoelectric effect. The shielding electrode layer 5 is coated on the surface of the piezoelectric functional layer 4 to isolate electromagnetic interference and stray signals in the body fluid environment, ensuring the stability and signal-to-noise ratio of the piezoelectric signal output by the signal electrode. The shielding electrode lead 6 is made of bioabsorbable conductive material and is used to conduct electrical signals. In addition, the directional current signal formed between the core electrode layer 2 and the shielding electrode layer 5 can act on vascular endothelial cells through electrophysiological regulation, promoting cell proliferation, migration and phenotypic optimization, and accelerating the vascular endothelial repair process.

[0033] Preferably, the material of the scaffold body 1 is polylactic acid (PLA), silk fibroin, polylactic acid / polycaprolactone (PLA / PCL) composite material, etc.; the core electrode layer 2, the shielding electrode layer 5, and the corresponding core electrode lead 3 and shielding electrode lead 6 are made of bio-absorbable conductive metal materials such as magnesium and magnesium alloys, zinc and zinc alloys, iron and iron alloys, and molybdenum, or conductive polymer composite materials (such as polylactic acid / polypyrrole (PLA / PPy) composite material, polycaprolactone / polyaniline (PCL / PANI) composite material, chitosan / graphene (CS / Graphene) composite material, etc.); the piezoelectric functional layer 4 is polarized poly-L-lactic acid (PLLA), chitosan, etc. β - Glycine, collagen, etc.; the encapsulation layer 7 is made of biodegradable silicone, porcine fibrin adhesive, polyethylene glycol hydrogel, etc.

[0034] The application scenarios for this negative Poisson's ratio intelligent vascular stent include: after implantation in a blood vessel, it is used to monitor intravascular pressure in real time and provide electrical stimulation to promote vascular tissue repair. When the blood vessel pulsates or pressure changes, the piezoelectric functional layer deforms and generates electrical signals. An external signal processing platform receives these signals and analyzes the vascular pressure data through the core electrode leads and shielding electrode leads. Simultaneously, it releases electrical signals through the core electrode leads and shielding electrode leads in contact with the inner wall of the blood vessel, stimulating endothelial cell growth and inhibiting excessive smooth muscle proliferation. This intelligent vascular stent integrates vascular support, real-time health monitoring, and electrical stimulation, providing an innovative solution for the treatment of cardiovascular diseases.

[0035] This invention proposes a negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials (see reference). Figure 4 The preparation process is as follows: (1) Select bio-absorbable conductive materials (such as magnesium-based alloys, biodegradable conductive polymer composites, etc.) as the core electrode layer (which also serves as the scaffold body). Use laser cutting, wire drawing and other processes to prepare a filament structure of the preset size, and lead out the core electrode wires by ultrasonic welding or adhesive bonding to ensure the stability of electrical signal transmission; (2) Degradeable piezoelectric functional layer is uniformly deposited on the outside of the core electrode layer by electrospinning process, or the core electrode layer is immersed in piezoelectric biomaterial solution (such as polylactic acid-hydroxyapatite composite solution, chitosan / collagen piezoelectric spinning solution, etc.) by dip-pull method to form a piezoelectric functional layer. After freeze drying, heat setting and polarization treatment, the piezoelectric functional layer forms an ordered piezoelectric active structure, giving the scaffold wire high efficiency mechanical-electric conversion performance; (3) Use bio-absorbable conductive materials (such as zinc) (3) The outer shielding electrode layer is prepared by magnetron sputtering, solution coating or electrospinning composite process, etc., based on alloy thin film, polypyrrole / polylactic acid composite conductive coating, conductive sodium alginate based composite material, etc. The thickness can be adjusted according to the preset service life of the scaffold, taking into account the electromagnetic shielding effect and degradation rate matching, and the shielding electrode lead wire is led out by ultrasonic welding or adhesive bonding; (4) Biodegradable gel materials (such as sodium alginate-gelatin composite gel, PLGA-PEG hydrogel, chitosan-based ion crosslinking gel, etc.) are selected, and the encapsulation layer is uniformly wrapped on the outside of the scaffold wire to form a functionalized scaffold wire by microfluidic coating or impregnation coating method, ensuring that the encapsulation layer is tightly attached and without cracks, realizing the dual functions of biocompatibility and mechanical protection; (5) The above functionalized scaffold wire is engraved with negative Poisson ratio structure texture (such as concave type, double arrow type, curved concave honeycomb structure, etc.) along the surface, such as Figures 1-3 The mandrel (auxiliary device, material can be biodegradable polycaprolactone or medical stainless steel) is arranged in an orderly manner, and the functionalized stent wire is made to have a negative Poisson's ratio structure by using laser welding, hot melt bonding or braiding molding process, so as to prepare a negative Poisson's ratio smart vascular stent adapted to different blood vessel diameters, ensuring that the stent maintains structural integrity and piezoelectric sensing stability after expansion.

[0036] This invention proposes a negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials (see reference). Figure 5 The preparation process can also be: (1) Select biodegradable polymer materials (such as polylactic acid (PLA), polycaprolactone (PCL), polylactic acid-glycolic acid copolymer (PLGA), chitosan-based composite materials, etc.), and use photopolymerization 3D printing (SLA) or fused deposition modeling (FDM) processes, based on preset negative Poisson ratio structural parameters (such as concave type, double arrow type, curved concave honeycomb structure, etc., such as Figures 1-3(1) As shown), prepare a scaffold mesh with precise porosity and mechanical adaptability (as the scaffold body) to ensure that the scaffold exhibits negative Poisson's ratio characteristics of lateral contraction when it expands; (2) Use biodegradable conductive materials (such as polypyrrole / PLGA composite conductive coating, conductive sodium alginate-gelatin composite material, zinc-based alloy nano-slurry, etc.) to form a uniform and continuous core electrode layer on the surface of the scaffold mesh through solution coating, magnetron sputtering or electrospinning composite process, and use ultrasonic welding or adhesive bonding to lead out the core electrode leads to ensure the stability and continuity of electrical signal transmission; (3) Degradeable piezoelectric functional layer is uniformly deposited on the outside of the core electrode layer through electrospinning process, or the scaffold mesh is immersed in piezoelectric biomaterial solution (such as polylactic acid-hydroxyapatite composite spinning solution, collagen / chitosan piezoelectric solution, etc.) by dip-pull method to form piezoelectric The functional layer is heat-set and corona polarized to form an ordered piezoelectric active structure, giving the stent network high efficiency mechanical-electric conversion performance; (4) Bio-absorbable conductive materials (such as polythiophene / PCL composite coating, magnesium-based alloy film, conductive hydrogel composite material, etc.) are selected to prepare the outer shielding electrode layer by solution immersion coating or magnetron sputtering process. Its thickness can be adjusted according to the preset service life of the stent, taking into account the matching of electromagnetic shielding effect and degradation rate, and the shielding electrode leads are led out by ultrasonic welding or adhesive bonding; (5) Biodegradable gel materials (such as sodium alginate-gelatin composite gel, PLGA-PEG hydrogel, ion crosslinked chitosan gel, etc.) are selected to uniformly wrap the encapsulation layer on the outside of the shielding electrode layer by microfluidic coating or impregnation coating method to ensure that the encapsulation layer is tightly attached and without cracks.

[0037] Therefore, this invention, based on existing technology, designs a negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials and its preparation method. Compared with existing products, this invention has the following significant advantages: 1. Strong dynamic monitoring capability: The negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials has extremely high sensitivity to changes in external pressure or deformation. It can capture minute mechanical signals and collect dynamic changes in intravascular pressure in real time, providing reliable data for the assessment of the real-time status of blood vessels after stent implantation and the quantitative analysis of the repair process.

[0038] 2. Possesses active vascular repair function: The negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials can generate electrical signals under external pressure. These signals can simulate the endogenous bioelectric microenvironment in the human body, thereby regulating the proliferation and migration behavior of vascular endothelial cells, promoting the rapid coverage of the stent surface by endothelial cells, and accelerating the repair process of the vascular intima. At the same time, the stent degradation products contain essential nutrients for the human body, which can further promote tissue repair and functional recovery after being absorbed in the body.

[0039] 3. Personalized adjustment of stent lifespan: Precise adaptation can be achieved through core structure thickness adjustment. For example, the thickness of the shielding electrode layer is positively correlated with the degradation cycle—increase its thickness when long-term support is required, and reduce it as needed before implantation when only short-term support is required; or use substrates with different degradation rates (magnesium alloy 1~3 months, zinc alloy 3~6 months, polylactic acid (PLA) 6~12 months, etc.) to further match personalized vascular repair cycles.

[0040] 4. Excellent biocompatibility: During the material selection and preparation process, this intelligent vascular stent can significantly improve its biocompatibility with human tissues by optimizing its surface physicochemical properties and chemical composition, thereby reducing the immune system's rejection response to the stent and providing a reliable guarantee for the long-term health and stability of blood vessels.

[0041] In summary, the intelligent vascular stent of this invention overcomes the limitations of existing technologies, integrating dynamic monitoring, active repair, and biocompatibility, providing an innovative solution for the treatment of cardiovascular diseases and the monitoring of vascular health. Example 1 In this embodiment, the intelligent vascular stent body is made of bioabsorbable metal material, such as... Figure 4 As shown.

[0042] (1) Select a 0.1 mm diameter magnesium wire as the core electrode layer (which also serves as the support body), and use ultrasonic welding process to lead out a 0.03 mm diameter molybdenum wire to ensure the conductivity and structural stability of the connection between the electrode and the wire.

[0043] (2) Dissolve poly-L-lactic acid (PLLA) powder in hexafluoroisopropanol (HFIP), stir magnetically for 6 h until completely dissolved, prepare a homogeneous electrospinning solution with a mass fraction of 4%, and let it stand for 30 min to remove bubbles before use.

[0044] (3) The degassed PLLA spinning solution was injected into a 60 mL syringe equipped with a No. 27 stainless steel needle. The spinning environment parameters were set as follows: temperature 40 ℃, relative humidity 20%. A 12 kV DC high voltage was applied between the needle and the receiving device (core electrode layer). The solution injection rate was controlled at 1 mL / h and the distance between the needle and the receiver was 15 cm. A piezoelectric biomaterial functional layer with a thickness of 5 μm was uniformly deposited outside the core electrode layer through electrospinning process to ensure that the coating is continuous and without cracks.

[0045] (4) Fix the sample obtained in step (3) on the rotating tray of the thermal evaporation coating machine, and set the tray rotation speed to 25 rad / min; evenly wind the magnesium wire around the surface of the tungsten wire evaporation source, close the coating machine chamber and evacuate to a pressure ≤ 2 × 10⁻⁶. -3Pa; connect the tungsten wire to a DC power supply and adjust the current to 55~60 A. A magnesium film with a thickness of 0.04 μm is uniformly deposited on the outside of the piezoelectric biomaterial functional layer as a shielding electrode layer through a thermal evaporation process. After the coating is completed, the sample is taken out and a molybdenum wire with a diameter of 0.03 mm is led out on the surface of the shielding electrode layer using an ultrasonic welding process.

[0046] (5) Fix the functionalized magnesium wire sample obtained in step (4) on the stage of the spin coater, use Ecoflex 00-30 silicone as the encapsulation material for uniform spin coating, and set the spin coating speed to 500~800 r / min; after spin coating, let it stand and cure for 4 h in an environment of 25 ℃ and 40% relative humidity to obtain a functionalized magnesium wire substrate with a complete encapsulation layer.

[0047] (6) Select a cylindrical stainless steel rod with a diameter of 2.5 mm as the substrate, and use a fiber laser to engrave concave, double arrow, and curved concave honeycomb negative Poisson ratio structure textures on its surface to make a molded mandrel; arrange the encapsulated functionalized magnesium wire substrate obtained in step (5) in an orderly manner along the mandrel texture using a multi-axis braiding machine, and use laser spot welding process to process the braiding nodes to form smooth spherical ends, ensuring no burrs and no sharp protrusions, and obtain the finished product of the intelligent vascular stent with negative Poisson ratio structure after demolding.

[0048] Example 2 In this embodiment, the smart vascular stent body is made of a biodegradable polymer material, such as... Figure 5 As shown.

[0049] (1) 0.1 kg of polylactic acid (PLA) foam material was selected and subjected to ultrasonic cleaning with deionized water (30 min, power 80W), high-speed mechanical crushing (speed 3000 r / min) and vacuum drying (60 ℃, 24 h) to obtain PLA particles with uniform particle size. The particles were loaded into the barrel of a fused deposition modeling (FDM) 3D printer. The concave, curved concave honeycomb structure and double arrow negative Poisson ratio topological structure mesh were designed by CAD software. A nozzle with a diameter of 0.4 mm was selected, and the printing temperature was set to 200 ℃, the layer thickness to 0.1 mm and the filling density to 60%. A support mesh with a size of 15 cm × 15 cm × 0.4 mm was printed layer by layer to ensure that the structure has uniform pores and stable mechanical properties.

[0050] (2) Fix the support mesh obtained in step (1) onto the rotating tray of the thermal evaporation coating machine (rotation speed 25 rad / min), use magnesium wire as the evaporation source and evenly wind it around the tungsten wire carrier; close the chamber and evacuate to a pressure ≤2×10 -3Pa, connect the tungsten wire to a DC power supply, adjust the heating current to 55~60 A, and uniformly deposit a magnesium film with a thickness of 0.04 μm on the surface of the support mesh through thermal evaporation process as the core electrode layer; after the coating is completed, take out the sample, and use ultrasonic welding process to lead out a molybdenum wire with a diameter of 0.03 mm at a preset position on the core electrode layer to ensure the continuity of electrical signal transmission.

[0051] (3) Slowly add 1.5 g of chitosan powder to 98.5 g of 1% (volume fraction) acetic acid aqueous solution and stir magnetically (500 r / min, 24 h) until completely dissolved to prepare a 1.5% (mass fraction) chitosan solution; add 1.2 g of glycine (crosslinking agent) to it and continue stirring for 30 min until the system is homogeneous to prepare a piezoelectric biomaterial composite solution; completely immerse the scaffold mesh in the solution and let it stand at room temperature for 24 h to achieve full wetting, then remove it and place it in a vacuum drying oven (25 ℃, 12 h) to dry, forming a uniform and dense piezoelectric biomaterial pre-coating; then place the sample in a corona polarization device and set the polarization parameters: polarization voltage 10 kV, polarization temperature 60 ℃, polarization time 30 min, and use corona discharge to orient the polar groups inside the material to form a stable piezoelectric active structure; after polarization, place it in a vacuum drying oven (25 ℃, 6 h) again. h) Post-processing is performed to finally obtain a piezoelectric biomaterial functional layer with both high orientation and good interlayer bonding.

[0052] (4) The sample obtained in step (3) is placed back into the thermal evaporation coating machine. Using the coating parameters (vacuum degree, current, rotation speed) of step (2), a magnesium film with a thickness of 0.04 μm is uniformly deposited on the surface of the piezoelectric biomaterial functional layer as a shielding electrode layer. After coating, a molybdenum wire with a diameter of 0.03 mm is led out using ultrasonic welding. The thickness of the electrode layer can be flexibly adjusted according to the preset service life of the scaffold (1~6 months) to balance the electromagnetic shielding effect and the degradation rate matching.

[0053] (5) Fix the cylindrical stent on the stage of the spin coater (600 r / min) and use Ecoflex 00-30 silicone for uniform spin coating and encapsulation. After spin coating, place the stent in a constant temperature and humidity chamber (25 ℃, relative humidity 40%) and let it stand for 4 h to complete curing, so as to obtain a negative Poisson's ratio smart vascular stent with a biocompatible encapsulation layer, ensuring that the encapsulation layer is free of cracks and bubbles and does not affect the negative Poisson's ratio mechanical properties of the stent.

[0054] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A piezoelectric biomaterial-based negative Poisson's ratio smart vascular stent, characterized by, The functionalized stent wire comprises a core electrode layer (2), a piezoelectric functional layer (4), a shielding electrode layer (5) and an encapsulation layer (7) which are sequentially laminated from inside to outside; the core electrode layer (2) is internally embedded with a core electrode lead (3), and the shielding electrode layer (5) is internally embedded with a shielding electrode lead (6). The intelligent stent with negative Poisson's ratio has a negative Poisson's ratio structure. The functionalized stent wire comprises a core electrode layer (2), a piezoelectric functional layer (4), a shielding electrode layer (5) and an encapsulation layer (7) which are sequentially laminated from inside to outside; the core electrode layer (2) is internally embedded with a core electrode lead (3), and the shielding electrode layer (5) is internally embedded with a shielding electrode lead (6). The functionalized stent wire comprises a core electrode layer (2), a piezoelectric functional layer (4), a shielding electrode layer (5) and an encapsulation layer (7) which are sequentially laminated from inside to outside; the core electrode layer (2) is internally embedded with a core electrode lead (3), and the shielding electrode layer (5) is internally embedded with a shielding electrode lead (6).

2. The negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials according to claim 1, wherein, The functionalized stent wire comprises a core electrode layer (2), a piezoelectric functional layer (4), a shielding electrode layer (5) and an encapsulation layer (7) which are sequentially laminated from inside to outside; the core electrode layer (2) is internally embedded with a core electrode lead (3), and the shielding electrode layer (5) is internally embedded with a shielding electrode lead (6). The functionalized stent wire comprises a core electrode layer (2), a piezoelectric functional layer (4), a shielding electrode layer (5) and an encapsulation layer (7) which are sequentially laminated from inside to outside; the core electrode layer (2) is internally embedded with a core electrode lead (3), and the shielding electrode layer (5) is internally embedded with a shielding electrode lead (6).

3. The negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials according to claim 2, wherein, The functionalized stent wire comprises a core electrode layer (2), a piezoelectric functional layer (4), a shielding electrode layer (5) and an encapsulation layer (7) which are sequentially laminated from inside to outside; the core electrode layer (2) is internally embedded with a core electrode lead (3), and the shielding electrode layer (5) is internally embedded with a shielding electrode lead (6). The core electrode layer (2), the shielding electrode layer (5), the core electrode lead (3) and the shielding electrode lead (6) each adopt a bioabsorbable metal conductive material or a conductive polymer composite material.

4. The negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials according to claim 1, wherein, The encapsulation layer (7) adopts degradable silica gel, porcine-derived fibrin adhesive or polyethylene glycol hydrogel. The intelligent stent with negative Poisson's ratio is connected to an external signal processing platform through the core electrode lead (3) and the shielding electrode lead (6).

5. The piezoelectric biomaterial-based negative Poisson's ratio smart vascular stent according to claim 1, wherein, The method comprises the following steps:

6. The negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials according to claim 1, wherein, The piezoelectric functional layer (4) is made of polarized poly-L-lactic acid, chitosan, β glycine or collagen.

7. The negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials according to claim 1, wherein, S1: a core electrode layer (2) is prepared by laser cutting and wire forming, and a core electrode lead (3) is led out by ultrasonic welding or adhesion; 8. The negative Poisson's ratio smart vascular stent based on piezoelectric biomaterials according to claim 1, wherein, S2: a piezoelectric functional layer (4) precursor is loaded outside the core electrode layer (2) by an electrospinning process or a dip-coating method, and then the piezoelectric functional layer (4) is prepared through freeze-drying, heat setting and polarization treatment; 9. A method for preparing a piezoelectric biomaterial-based negative Poisson's ratio smart vascular stent according to any one of claims 1 to 8, characterized by, S3: a shielding electrode layer (5) is prepared outside the piezoelectric functional layer (4) by a magnetron sputtering, solution coating or electrospinning process, and a shielding electrode lead (6) is led out by ultrasonic welding or adhesion; S4: an encapsulation layer (7) is prepared outside the shielding electrode layer (5) by a microfluidic coating or immersion coating method, and a functionalized stent wire is formed; S5: the functionalized stent wire is arranged along an auxiliary device with negative Poisson's ratio structure lines on the surface, and the intelligent stent with negative Poisson's ratio is formed by laser welding, hot melt adhesion or braiding forming process. The method comprises the following steps: S1: a stent body (1) with a negative Poisson's ratio structure is prepared by a photocuring 3D printing or a fused deposition modeling process; ​ 10. A method for preparing a piezoelectric biomaterial-based negative Poisson's ratio smart vascular stent according to any one of claims 1 to 8, characterized by, ​ ​ S2: forming a uniform and continuous core electrode layer (2) on the surface of the stent body (1) by solution coating, magnetron sputtering or electrospinning process, and leading out the core electrode lead (3) by ultrasonic welding or adhesion; S3: loading the precursor of the piezoelectric functional layer (4) outside the core electrode layer (2) by electrospinning process or dip-coating method, and then preparing the piezoelectric functional layer (4) through heat setting and polarization treatment; S4: preparing the shielding electrode layer (5) outside the piezoelectric functional layer (4) by solution dip-coating or magnetron sputtering process, and leading out the shielding electrode lead (6) by ultrasonic welding or adhesion; S5: preparing the encapsulation layer (7) outside the shielding electrode layer (5) by microfluidic coating or dip-coating method, forming the negative Poisson's ratio intelligent blood vessel stent.

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