50 results about "Intravascular stent" patented technology

The invention discloses a magnesium alloy corrosion resistance prediction method based on machine learning, and relates to the technical field of metal material performance prediction.The method comprises the following steps that magnesium alloy corrosion resistance data are obtained and preprocessed, and a magnesium alloy data set is obtained; aiming at a random forest algorithm and a gradient boosting tree algorithm, training, optimizing and evaluating the prediction model by using the magnesium alloy data set to obtain an optimal prediction model; and for the optimal prediction model, inputting components and environmental parameters of the magnesium alloy, and outputting a corrosion resistance prediction value. According to the method, the prediction precision and the material design efficiency can be remarkably improved, the method is suitable for biomedical application of orthopedic implants, intravascular stents and the like, and an efficient and reliable technical path is provided for research and development of the degradable magnesium alloy.

The invention discloses a functional coating, an intravascular stent and a preparation method and application of the intravascular stent. The functional coating comprises an endothelialization promoting active substance and an anti-proliferation drug; the endothelialization promoting active substance comprises at least one of polypeptide containing an RGD sequence, polypeptide containing a YIGSR sequence, polypeptide containing an REDV sequence, a beta-polypeptide polymer or a beta-polypeptide-polyester block copolymer. The functional coating disclosed by the invention can be used for surface functional modification of interventional medical devices, can selectively promote adhesion and proliferation of vascular endothelial cells at an implantation part, realizes rapid endothelialization, and can controllably release an anti-proliferation drug to inhibit excessive proliferation of vascular smooth muscle cells, so that the vascular endothelial cells are prevented from being damaged. Therefore, the risks of restenosis and advanced thrombus are effectively reduced.

The invention relates to a cross-joint intravascular stent and a preparation method thereof. The cross-joint intravascular stent comprises a first part and a second part which are distributed in the axial direction of the cross-joint intravascular stent. The first part comprises a plurality of first stent rings which are arranged at intervals in the axial direction of the joint-crossing intravascular stent and are mutually independent, and a whole-surface covering film fixedly arranged on the first stent rings; from the proximal end to the distal end, the distance between every two adjacent first stent rings is gradually increased; the second part comprises a plurality of second stent rings which are arranged at intervals in the axial direction of the joint-crossing intravascular stent and are mutually independent, and a plurality of rows of connecting membrane groups which are sequentially arranged in the axial direction of the joint-crossing intravascular stent; each row of connecting membrane group comprises a plurality of connecting membranes which are uniformly distributed in the circumferential direction of the joint-crossing intravascular stent, and the two ends of each connecting membrane are fixedly connected with the two adjacent second stent rings respectively; the width of the rods forming the first stent ring is greater than the width of the rods forming the second stent ring.

The invention provides a porous cell auxetic material, an absorbable intravascular stent, a preparation device and a preparation method, and belongs to the field of medical instruments, holes in porous cells are dumbbell-shaped structural holes, and the dumbbell-shaped structural holes are transversely and vertically alternately formed in the long axis direction and also transversely and vertically alternately formed in the short axis direction; dumbbell-shaped structure holes in a transverse and vertical alternating array are formed, and the short shafts of the dumbbell-shaped structure holes are provided with anti-springback inserting and pulling abutting supporting structures; the shape of the auxetic material during expansion is maintained, shrinkage is prevented when the auxetic material is axially compressed, and lasting supporting force is provided; when the vascular stent is formed by adopting the structure, radial and axial contraction of the vascular stent is prevented, the shape of the vascular stent is maintained, reliable radial supporting force is provided, the smoothness of the blood vessel is ensured, the mechanical performance of the biological absorbable stent is improved, the use amount of the biological absorbable polymer material is reduced, and the wall thickness is reduced.

This invention relates to an endovascular stent, comprising a first sub-stent and a second sub-stent, both woven from multiple braided filaments into a mesh-like structure; the first sub-stent and the second sub-stent are coaxially arranged; a flexible element is connected at one end to one end of the first sub-stent and at the other end to one end of the second sub-stent; the flexible element has a helical or variable-diameter helical structure; when the flexible element has a variable-diameter helical structure, the outer diameter of the flexible element gradually increases and then gradually decreases from the proximal end to the distal end; by adjusting the distance between the first sub-stent and the second sub-stent, the flexible element undergoes elastic deformation, thereby adjusting the metal coverage between the first sub-stent and the second sub-stent.

The utility model discloses an intravascular stent electrode system which comprises an intravascular stent, an electrode contact, a guide wire, a signal collecting unit and a receiving coil, the intravascular stent can be implanted into a target area of an intracranial vascular system through an operation, and the electrode contact is connected to the intravascular stent and can collect intracranial signals. The guide wire can conduct stimulation current to the electrode contact and transmit signals collected by the electrode contact, the signal collecting unit is connected with the guide wire and can collect the signals transmitted by the guide wire, and the receiving coil is arranged on the signal collecting unit and forms electromotive force through a magnetic field. The electromotive force is converted by the power supply chip and then continuously supplies power to the signal collection unit and the electrode contact, so that the stable work of the signal collection unit can be maintained.

The utility model relates to the technical field of medical instruments, and discloses an intravascular stent structure capable of reducing pressure stress, the intravascular stent is of a tubular net rack structure and comprises a plurality of annular wave rods and stent connecting rods, the annular wave rods are arranged in the axial direction of the intravascular stent, a plurality of stent connecting rods are arranged on one side of each wave rod, and the stent connecting rods are arranged on the other side of each wave rod. One end of each support connecting rod is connected with an adjacent wave rod, the section of each wave rod is arranged in a wave shape, and the support is characterized in that no less than one group of pressure stress parts capable of reducing the pressure stress of the wave rods are arranged on the side surfaces of the wave rods; due to the design of the wave-shaped wave rods and the pressure stress part, the support has more elastic deformation space, when the support is stressed, the support can elastically deform to a certain degree at the fluctuation of waves and the bending part of the pressure stress part instead of directly bearing all the pressure like a rigid structure, and the elastic deformation absorbs part of the pressure, so that the stress resistance of the support is improved. Therefore, the pressure stress is reduced.

The present invention relates to an internal duct and fixing system (100) for branches for endovascular endoprostheses for endovascular treatment of aneurysms or dissections of the aorta, comprising (i) an endoprosthesis (200) provided with windows (210, 220, 230, 240), (ii) one or more occlusions (215, 225, 235, 245), fixed to the endoprosthesis (200) by means of suture (216, 226, 236, 246), reversibly occluding the windows (210, 220, 230, 240), and a set of fixing and duct elements (300) that forms one or more internal channels of the endoprosthesis (200), preferably in the region adjacent to one of the windows (210, 220, 230, 240). The present invention also relates to a corresponding endoprosthesis (200).

This invention is directed to an expandable stent for implantation in a body lumen, such as an artery, and a method for making it from a single length of tubing. The stent consists of a plurality of radially expandable cylindrical elements generally aligned on a common axis and interconnected by one or more links. A Y-shaped member is comprised of a U-shaped member and a link having a curved portion and a straight portion to improve the flexibility and thereby improve the fatigue performance of the Y-link junction.

The invention provides a separable microcatheter and stent conveying system and method, and belongs to the technical field of neural intervention and vascular intervention. The system comprises a separable micro-catheter which is formed by detachably connecting a near-section micro-catheter (1) and a far-section micro-catheter (2) through a physical clamping structure; the stent conveying system comprises a conveying guide wire (3) and an intravascular stent (4), and the conveying guide wire (3) is provided with an anchoring stent (31) matched with the limiting cavity of the far-section micro catheter (2). The guide wire, the catheter and the stent conveying system are integrated, so that the vascular interventional operation process is obviously optimized. The system adopts a separable microcatheter design and a mechanical anchoring structure, so that a guide wire and a catheter do not need to be exchanged for many times in the operation process, and the number of times of instrument operation is fundamentally reduced. According to the invention, the operation time is shortened, the exposure time of an operator and a patient under X-rays is directly reduced, and the radiation dose is effectively controlled.

A bifurcated intravascular stent graft comprises primary stent segments and a primary graft sleeve, forming a main fluid channel and having a side opening therethrough. An external graft channel formed on the primary graft sleeve has a first end communicating with the side opening and an open second end outside the primary graft sleeve, thereby providing a branch flow channel from the main channel out through the side opening and external graft channel. The primary stent segments and graft sleeve engage an endoluminal surface of a main vessel and form substantially fluid-tight seals. The stent graft further comprises a secondary stent graft, which may be positioned partially within the external graft channel, through the open second end thereof, and partially within a branch vessel. The secondary stent graft engages the inner surface of the external graft channel and the endoluminal surface of the branch vessel, thereby forming substantially fluid-tight seals.

The invention provides a drug-loaded intravascular stent and a preparation method thereof.The preparation method of the drug-loaded intravascular stent comprises the steps that drug-loaded microspheres are prepared; wherein the drug-loaded microspheres comprise chitosan nanoparticles loaded with an anti-inflammatory drug, an antibacterial drug layer coating the chitosan nanoparticles, and a PLGA (poly (lactic-co-glycolic acid)) shell layer coating the antibacterial drug layer; mixing the drug-loaded microspheres with PLGA (poly (lactic-co-glycolic acid)) microspheres to prepare a blended wire rod; and according to a digital model, carrying out 3D printing on the blended wire rod to form the drug-loaded intravascular stent.

The invention provides a degradable zinc alloy intravascular stent which is of a tubular net structure and comprises a plurality of supporting rings (3) arranged in the axial direction and connecting rods (1) connected with the adjacent supporting rings (3). The supporting ring (3) is in a wave shape and is composed of a plurality of supporting rod units which are connected in sequence, each supporting rod unit comprises a first supporting rod in the middle and two arc-shaped parts connected to the two ends of the first supporting rod respectively, and wave crests or wave troughs of the supporting ring (3) are formed at the tops of the arc-shaped parts; every two adjacent supporting rod units are connected by sharing one arc-shaped part; the rod diameter (42) of the middle position (2) of the first supporting rod is W1, and the rod diameter of the first supporting rod is gradually increased from the middle position (2) of the first supporting rod to the arc-shaped parts at the two ends of the first supporting rod. The rod diameter (41) of the supporting ring (3) at the wave crest and the wave trough is W2, and W2 is larger than W1. The rod diameter (32) of the connecting rod (1) is W3, and W3 is smaller than W1.

The invention discloses a method for simulating unfolding of an intravascular stent, electronic equipment and a computer readable storage medium, and the method comprises the steps: building a simplified compression model of the intravascular stent in a microcatheter based on the size of the microcatheter, the simplified compression model comprises node particles on a simplified spiral line of a weaving wire and ghost particles on a central axis section of the intravascular stent; acquiring a blood vessel model comprising the target blood vessel segment, wherein the blood vessel model comprises a blood vessel center line and a blood vessel wall; the simplified compression model is arranged along the center line of the blood vessel, the ghost particles are located on the center line of the blood vessel, and the node particles surround the center line of the blood vessel to form a spiral structure; and carrying out geometric shape constraint and physical elastic constraint on the intravascular stent, and simulating an expansion process of the intravascular stent in the target vascular section to obtain an expansion model of the intravascular stent. According to the method provided by the embodiment of the invention, a reliable stent unfolding form can be obtained.

The invention discloses a high-performance thin-wall microtube for a magnesium alloy intravascular stent, the high-performance thin-wall microtube is prepared from magnesium alloy, and the magnesium alloy comprises the following components in percentage by mass: 1-3% of Zn, 0.2-2% of Mn and the balance of Mg. The invention also discloses a preparation method of the thin-wall microtube, which comprises the following steps: obtaining a magnesium alloy cast ingot by adopting ultrasonic smelting in a protective atmosphere, and then preparing a high-plasticity microtube extrusion blank through an extrusion-upsetting-extrusion combined extrusion process, so that the formability and stability of the extrusion microtube are improved; the magnesium alloy thin-walled tube is prepared by machining, perforating and performing hot extrusion to obtain an ultra-long hollow tube blank, and replacing the traditional multi-pass cold drawing process with single-pass hot rolling micro-tube forming. The preparation method has the beneficial effects that the prepared magnesium alloy thin-wall microtube is high in strength, excellent in plasticity and corrosion resistance and good in physiological tolerance, and the mechanical property requirements of intravascular stent forming and balloon dilatation can be met.

The invention relates to the technical field of medical materials, in particular to a medical magnesium alloy composite material and a preparation method and application thereof. The degradation rate of the medical magnesium alloy composite material is regulated and controlled by regulating and controlling the thickness of the polymer-drug-loaded nano-microsphere composite coating, the larger the thickness is, the slower the degradation rate is, and the thinner the thickness is, the faster the degradation rate is; the drug release rate of the medical magnesium alloy composite material is regulated and controlled by regulating and controlling the spatial distribution of the drug-loaded nano-microspheres in the polymer-drug-loaded nano-microsphere composite coating, so that the drug can be quickly and slowly released, and specifically, the more intensive the spatial distribution of the drug-loaded nano-microspheres (namely, the more the number of the drug-loaded nano-microspheres) is, the faster the drug is released. According to the preparation method disclosed by the invention, magnesium alloy degradation and drug release can be synergistically regulated and controlled, and the clinical application requirements of magnesium alloy intravascular stent customization, such as more sustained release energy, less sustained release energy and fast and slow degradation, are met.

The invention discloses a magnetic induction power generation intravascular stent, a treatment system and a control method thereof, and relates to the technical field of vascular intervention medical instruments. The system comprises a stent serving as an implantation unit and an in-vitro unit, the stent body is of a tubular woven structure, and a closed loop composed of conductive fibers is integrated in the stent body and used for cutting magnetic induction lines for power generation. The in-vitro unit comprises a magnetic field generating device for generating a rotating magnetic field, a driving device and a processing unit. The invention further provides a control method of the system, and the output current of the support is dynamically controlled by adjusting magnetic field parameters. Energy is transmitted through wireless magnetic induction, so that the stent generates controllable electrical stimulation on local blood vessels on the premise that a built-in battery is not needed, the problems that an existing electrified stent is short in power supply service life, uncontrollable in parameter and high in biological safety risk are effectively solved, vascular endothelial repair can be accurately promoted, abnormal proliferation of smooth muscle cells is inhibited, and the vascular endothelial repair rate is increased. The problem of restenosis in the stent is effectively prevented and treated.

The invention relates to the technical field of biomedical materials and drug delivery systems, in particular to a preparation method of a microporous polylactic acid drug-loaded coating. Comprising the following steps: coating a polylactic acid coating on the surface of a substrate; then a mixed solution of trichloromethane and N, N-dimethylformamide is used as a pore-forming solution, the coating is subjected to dipping treatment and curing under the condition that the relative humidity is 55-95%, and a microporous structure is formed; and finally, realizing drug loading in a manner of soaking or directly dissolving the drug in the pore-forming liquid. By adjusting the volume ratio (5-70%) of N, N-dimethylformamide in the mixed solvent and the environment humidity and temperature, the porous morphology of the coating from surface single-layer pores to internal through spongy pores can be dynamically regulated and controlled. The method is simple in process, mild in condition, suitable for the surfaces of medical devices in complex shapes, capable of achieving high load and controllable slow release of the medicine and capable of being used for preparing medicine-carrying medical devices such as intravascular stents and catheters.

The invention discloses a composite material for preparing a flexible, dredged and degradable lymphatic vein anastomosis stent as well as a process and application thereof. The material is a functionally gradient composite fiber felt constructed based on a coaxial electrospinning technology, and comprises a structural skeleton matrix, an intelligent drug release system and a surface functionalization system. The structural framework matrix comprises a PLGA (poly (lactic-co-glycolic acid)) and PLLA blend, magnesium-based nanoparticles and nano tantalum powder; the intelligent drug release system comprises an environmental response type hydrogel carrier, rapamycin and heparin sodium; the surface functionalization system is covalently grafted RGD polypeptide. The preparation method comprises the steps of raw material pretreatment, composite spinning solution preparation, core-shell fiber preparation, integrated enhanced stabilization treatment, surface functional modification and sterilization. Through a unique material formula and process design, integration of multiple functions of flexible supporting, degradation controllability, intelligent drug release, endothelialization promotion, development and the like is achieved, and the problem of adaptability of a traditional intravascular stent in lymphatic vein anastomosis is effectively solved.

The utility model discloses a connecting structure of an intravascular stent, and relates to the technical field of intravascular stents. The device comprises a plurality of first connecting rods which are symmetrically distributed, metal supports are fixedly connected to the ends, away from each other, of the first connecting rods on the two sides, a PLLA support is arranged between the metal supports on the two sides, and connecting mechanisms are arranged between the first connecting rods and the PLLA support, so that the effects that welding is not needed, the structure is simple, the process implementation difficulty is low, and the cost is low are achieved. And the connection is stable.

The disclosure relates, in part, to computer-based visualization of stent position within a blood vessel. A stent can be visualized using intravascular data and subsequently displayed as stent struts or portions of a stent as a part of a one or more graphic user interface(s) (GUI). In one embodiment, the method includes steps to distinguish stented region(s) from background noise using an amalgamation of angular stent strut information for a given neighborhood of frames. The GUI can include views of a blood vessel generated using distance measurements and demarcating the actual stented region(s), which provides visualization of the stented region. The disclosure also relates to display of intravascular diagnostic information such as indicators. An indicator can be generated and displayed with images generated using an intravascular data collection system. The indicators can include one or more viewable graphical elements suitable for indicating diagnostic information such as stent information.

Inventors have synthesized peptides allowing an engagement of intact CD31 molecules on all the healthy endothelial cells and resting blood platelets and leukocytes that can enter in contact with an implanted device. Those cells can therefore receive the “leave-me-alone” signal delivered by the trans-homophilic engagement of CD31, which is essential to maintain the homeostasis in the circulation and vascularized tissues. Thrombotic or life-threatening occurrence of hemorrhagic or thromboembolic complications have impaired the use of endovascular devices. The devices bearing the mimicking peptides of the present invention are rapidly integrated, because they are perceived by blood platelets and leukocytes as a healthy endothelium, a “self” component. Furthermore, their ability to be rapidly endothelialized with a physiologic endothelial cell phenotype also limits platelet and leukocyte activation at the site of device implantation in the long-term. Accordingly, the present invention relates to peptides mimicking the trans-homophilic CD31-CD31 domain 1 and 2 intercellular interaction.

The invention discloses a chitosan-based antibacterial fiber, a chitosan-based antibacterial fabric, a preparation method of the chitosan-based antibacterial fiber and application of the chitosan-based antibacterial fabric. The preparation method comprises the following steps: firstly, carrying out wet spinning to obtain chitosan fibers, and meanwhile, carrying out self-assembly on the surfaces of the chitosan fibers to form a nano-composite functional layer consisting of polydopamine, reduced graphene oxide and nano-silver; secondly, the chitosan composite fibers are immersed in a polyethylene glycol derivative solution containing aldehyde groups, chitosan amino groups on the surfaces of the fibers and the aldehyde groups in the acid solution are subjected to a cross-linking reaction, and a Schiff base cross-linked network is formed; and finally, carrying out surface coating on the cross-linked chitosan composite fiber by using a solution containing low-molecular-weight chitosan and a therapeutic drug to form a drug outer layer, so as to obtain the chitosan-based antibacterial fiber. The chitosan-based antibacterial fiber and fabric disclosed by the invention integrate multiple functions of long-acting antibiosis, pH-responsive drug release, anticoagulation, healing promotion and the like, and provides an artificial blood vessel and an intravascular stent membrane covering material which can simultaneously solve clinical problems of infection, thrombus, intimal hyperplasia and the like.

The invention discloses a tissue engineering vascular smooth muscle remodeling method based on a conducting polymer and application thereof. The invention finds that the conductive polymer plays a role in promoting the migration of vascular smooth muscle cells and guiding the functional remodeling of the vascular smooth muscle cells. According to the method, a conducting polymer synthesized by biological enzyme is stably modified on a tissue engineering blood vessel in three modes of direct soaking, click chemical grafting or gelatin sponge stent loading. The conductive modified intravascular stent can reconstruct an electrophysiological microenvironment similar to a natural blood vessel, can significantly guide smooth muscle cells to orderly migrate and arrange along the circumferential direction of the blood vessel, and promotes the smooth muscle cells to be transformed to contraction phenotypes expressing markers such as alpha-SMA, SM22alpha, CNN1 and the like, so that a smooth muscle layer close to an autologous blood vessel is structurally and functionally reconstructed. According to the invention, the bottleneck of insufficient functional remodeling of the tissue engineering vascular smooth muscle layer in the prior art is broken through, and a new strategy is provided for regeneration treatment of cardiovascular diseases.

The invention provides a Fe-Zn alloy micro slender tube for a degradable intravascular stent and a preparation method of the Fe-Zn alloy micro slender tube, and belongs to the technical field of biomedical degradable materials. Firstly, electroplating liquid is prepared; secondly, an aluminum alloy pipe is selected as a cathode mandrel, the surface of the aluminum alloy pipe is activated, and a to-be-plated base body is obtained; finally, pure iron is used as an anode to be installed in an electrolytic bath, a to-be-plated base body is used as a cathode mandrel to be horizontally placed in the electrolytic bath, and a Fe-Zn alloy plating layer is deposited on the surface of the cathode through an electroplating method; and after electroplating is completed, the cathode mandrel with the Fe-Zn alloy coating is immersed in an alkaline solution, the cathode mandrel is dissolved and removed at the room temperature, and the Fe-Zn alloy microtube is obtained. The modular multi-anode group design is adopted, and dynamic optimization of the number of anodes and anode circuit connection points is achieved; the gradient of the cathode electric field can be accurately compensated, and the phenomenon of uneven coating wall thickness is eliminated; and the limitation of a traditional fixed anode can be broken through, and the controllable electroplating requirements of the length and diameter of the pipe are met.

The utility model particularly relates to an absorbable stent which comprises a first stent body and a second stent body, the first stent body is of a tubular structure and comprises a plurality of metal wires which are woven in a staggered mode, and the metal wires comprise one or two of molybdenum wires and molybdenum alloy wires. The second stent is arranged on the peripheral surface of the first stent, and the second stent comprises absorbable polymer filaments. The absorbable stent disclosed by the utility model has good structural performance, realizes that the whole body of the stent is visible in the pushing and releasing process, and is beneficial to avoiding the defects that the continuous external expansion force causes damage to the endovascular intima, the inflammation of the endovascular intima is possibly induced, restenosis is caused by excessive hyperplasia and the like, and the absorbable stent is suitable for being used in the medical field. Therefore, the problem that an existing absorbable intravascular stent is poor in using effect can be effectively solved.

The invention discloses a medical magnesium alloy intravascular stent and a preparation method thereof, and belongs to the technical field of medical biological materials and medical instruments. The stent comprises a magnesium alloy matrix, a hollow tubular structure and a surface modification layer, wherein the magnesium alloy matrix consists of the following components in percentage by mass: 90-98% of Mg, 1-5% of Zn, 0.1-1% of Ca, 0.5-3% of Y and unavoidable impurities; the pipe diameter of the hollow tubular structure is 2-5mm, the pipe wall thickness is 0.1-0.3 mm, the length is 8-30mm, and the hollow tubular structure is a rhombic grid (the side length is 0.5-1.5 mm); and the surface modification layer is a hydroxyapatite-chitosan composite coating with the thickness of 5-20 microns. The preparation method comprises the steps of magnesium alloy cast ingot preparation, pipe preparation, stent forming, surface modification and sterilization. The degradation period of the stent is 3-6 months (matched with the vascular repair period), the radial supporting force is larger than or equal to 8 N, the bending radius is smaller than or equal to 5 mm, the hydrogen generation amount is reduced by 40-60% compared with that of a pure magnesium stent, biocompatibility is good, adhesion and proliferation of vascular endothelial cells can be promoted, the preparation process is simple, cost is low, and the stent is suitable for treating vascular stenosis or clogging diseases.

The utility model discloses an intravascular stent, and belongs to the technical field of intravascular stents. Comprising a support ring, telescopic assemblies are arranged at the top of the support ring, each telescopic assembly comprises a fixing plate, an air inlet is formed in the side wall of the fixing plate, an inflation pipe is arranged at one end of the air inlet, an air bag is arranged at one end of the inflation pipe, an air guide pipe is arranged on the other side of the air bag, and a moving plate is arranged on the circumferential outer wall of the air guide pipe; a medicine storage groove is formed in an inner cavity of the support ring, and a plurality of medicine outlet holes are formed in the circumferential outer wall of the support ring. Air is conveyed to the inflation tube through the air inlet, the air bag is expanded, the movable plate is pushed to move outwards, extending and unfolding of the intravascular stent are facilitated, the air inlet is closed through the cover plate to prevent air from leaking after installation is completed, medicine is stored through the medicine storage groove, the service life of the intravascular stent is effectively prolonged, and the service life of the intravascular stent is prolonged. Displacement of the intravascular stent is avoided through the fixing assembly. The structural design is convenient to adapt to different length requirements, and the stability is high.

The utility model discloses a four-column guide type superplastic extrusion die for a high-precision magnesium alloy microtube for an intravascular stent. The die is composed of a charging barrel, a charging barrel transverse positioning plate, an extrusion rod, an extrusion rod transverse positioning plate and guide columns. The utility model provides a four-column guide type extrusion die for a high-precision small-size magnesium alloy microtube, aiming at solving the problem that the eccentricity of a hot extrusion tube is relatively large due to the inclination of an extrusion rod of the magnesium alloy microtube or the non-concentric rod barrel of the extrusion rod. And inclination or non-concentricity of the extrusion rod and the charging barrel in the extrusion displacement process is corrected, and the magnesium alloy microtube with the uniform wall thickness is prepared. The device is suitable for the magnesium alloy microtube with the wall thickness smaller than 0.3 mm and has the advantages of being simple, convenient and fast to disassemble and accurate in positioning, the prepared magnesium alloy microtube has high concentricity, and the deviation is smaller than 4% (Tmax-Tminlt; t * 4%).

The invention discloses a stent coating and a preparation method thereof.The preparation method comprises the steps that firstly, dopamine is used for conducting chemical crosslinking on the surface of a stent, and an amino-rich surface is provided for subsequent grafting; then grafting p-azidobenzoic acid on the surface of the polydopamine by adopting an amidation reaction, and finally, firmly grafting the lipidosome to the surface of the material through a covalent grafting reaction of an azido group on the p-azidobenzoic acid and cycloalkyne on the lipidosome, so as to construct the multifunctional intravascular stent coating with anti-inflammatory and endothelial protection effects at the same time. The coating can adapt to long-term physiological functions required by the cardiovascular stent, and the lasting intravascular stent coating provides a solution strategy for complications such as stent restenosis and advanced thrombus.