CN106730049B

CN106730049B - Biocompatible internal stent material

Info

Publication number: CN106730049B
Application number: CN201611208251.4A
Authority: CN
Inventors: 李鸣涛; 邓焯键; 石佳明
Original assignee: Shenzhen Hno Medical Technology Co ltd
Current assignee: SHENZHEN HNO MEDICAL TECHNOLOGY Co.,Ltd.
Priority date: 2016-12-22
Filing date: 2016-12-22
Publication date: 2020-05-12
Anticipated expiration: 2036-12-22
Also published as: CN106730049A

Abstract

A biocompatible endoprosthesis material, comprising: a matrix of a material that is degradable in the tissue body, the matrix being tubular with inner and outer tubular surfaces, the inner surface forming a channel for passage of tissue fluid, such as blood. The surface is provided with a structure communicated with the inside and the outside; microcavity: the micro-cavity is obtained in the direction of the cross section of the matrix body, which is perpendicular to the axial direction, of the communication structure, the micro-cavity is located in the thickness direction of the hole, and the plane of the opening of the micro-cavity is basically perpendicular to the inner surface and the outer surface of the tubular support; composition (A): loaded in the micro-cavity and can degrade to release Fe³⁺(ii) a Short peptide layer: the short peptide layer is positioned on the inner surface and the outer surface of the matrix material, the short peptides can be self-assembled to form hydrogel, and the hydrogel formed after the short peptides are self-assembled can be specifically beneficial to the creeping covering of endothelial cells and the regeneration of an endothelial layer; the prosthesis can endow the required biocompatibility, has the balance creeping of an EC layer while keeping the support force of the stent, inhibits restenosis, and timely restores the self performance of tissues, particularly blood vessels.

Description

Biocompatible internal stent material

Background

The invention belongs to the field of medical materials, relates to a prosthesis material, in particular to a stent material with biocompatibility, and is more suitable for an intravascular stent material.

The body includes various passageways such as arteries, other blood vessels, and other body lumens. Sometimes these channels can become plugged or weakened. For example, the channel may be blocked by a tumor, stenosed by plaque, or weakened by an aneurysm. When these conditions occur, the passage may be reopened or enhanced, or even replaced, using the medical endoprosthesis. Endoprostheses are generally tubular members that are placed in a lumen in the body. Examples of endoprostheses include stents, covered prostheses, graft stents, and vascular closure pins.

Stents (stents), venous filters, expandable frames and similar implantable medical devices, hereinafter collectively referred to as stents, are radially expandable endoprostheses, typically intravascular implants that can be implanted into a blood vessel and radially expanded after percutaneous introduction. The stent can be implanted into various body cavities or various vessels, such as a vascular system, a urinary pipeline, a bile duct, a fallopian tube, a coronary vessel, a secondary vessel and the like. Stents may be used to support a body vessel and prevent restenosis after angioplasty within the vascular system. They may be self-expanding, for example, by an internal radial force when mounted on the balloon, or a combination of self-expansion and balloon-expandable (hybrid-expandable).

Well-known materials of construction for stents include polymers, organic fabrics, and biocompatible metals. Metals and/or alloys of these metals that have been used to construct the stent and/or components thereof include, but are not limited to, shape memory alloys such as stainless steel, iron, magnesium, gold, silver, tantalum, titanium, chromium, cobalt, and nickel titanium. The degradable materials commonly used for the stent include polymers, such as polylactic acid (PLA), metals, such as iron and magnesium, etc., however, polymers, such as PLA, easily cause an acidic matrix microenvironment during degradation, and the acidic environment is not conducive to further repair and growth of the tissue environment, and metals, such as magnesium and iron, degrade too fast or too slow, and have the defect of poor biocompatibility.

Since the first Bare Metal Stent (BMS) was placed into the human body in 1985, stent interventional therapy successfully solved the problem of high restenosis rate in the time of pure balloon dilatation, and became the main means of clinical treatment. Restenosis (ISR) is a repair response after local vascular injury, and its formation mechanism is mainly the result of proliferation and migration of vascular endothelial cells (SMC) into the intima, thrombosis, etc., caused by injury of SMC after injury of SMC, platelet adhesion, growth factor stimulation, etc. The damage to the local vascular intima caused by the stent implantation process stimulates the proliferation of vascular intimal tissue and the proliferation of smooth muscle cells. Restenosis caused by thrombus re-formation and the like, in-stent restenosis occurs in 20-30% of cases, and the incidence rate of ISR can reach 30-70% in patients with diabetes, small vessel lesion, long lesion, chronic total occlusion lesion and bifurcation lesion. Therefore, ISR has become the leading cause of long-term efficacy in stenting procedures.

Drug Eluting Stents (DES) were introduced in 2002, and DES has significant advantages over BMS in different types of coronary lesions, with a greatly reduced incidence of restenosis after Percutaneous Coronary Intervention (PCI). However, just as DES began to be used in large numbers in the clinic, the problem of late stage thrombosis in the stent emerged from the surface. The mechanisms include high reactivity of the vessel to the drug/polymer coating, incomplete stent endothelialization, and poor adhesion. The medicine greatly inhibits the hyperplasia of cell intima in the degradation and release process of the polymer, reduces the restenosis problem of stent implantation, and simultaneously causes the reduction of cell skin climbing so as to lead the stent to be difficult to be well healed with the vessel wall and the like. While prolonged dual anti-platelet procedures may reduce the incidence of late thrombosis within the stent, they also carry a bleeding risk.

The current common drug-coated stent for preventing restenosis mainly contains drug-coated stents such as rapamycin, paclitaxel, antibody and the like, but the coating drugs such as rapamycin and the like mainly inhibit the proliferation and migration of smooth muscle, but also inhibit the proliferation of endothelial cells, destroy the endothelialization of blood vessels and delay the natural healing of the blood vessels.

It is known that blood coagulation can be inhibited by the presence of charges on the surface of the stent to prevent restenosis caused by thrombus. US2006/0106451 discloses an electronic anticoagulant stent structure. The support structure includes a pair of coaxial metal supports having a layer of dielectric material between the supports. Preferably, a battery is used to connect the upstream end of the stent near or adjacent to its deployment. The positive terminal of the battery establishes an electrical connection with the outer metal holder and the negative terminal establishes an electrical connection with the inner metal holder, which exhibits a capacitor-like behavior. The negatively charged inner metal stent repels platelets and has an antithrombotic effect. CN104093431 discloses a stent having a coating of an electret structure formed by coating tantalum pentoxide or polytetrafluoroethylene on the stent. However, the above structures have complex preparation processes, and simultaneously, incompatible or non-degradable components are required to be introduced into human tissues, which easily causes the reduction of the biocompatibility of the stent, thereby also inhibiting the proliferation of endothelial cells and delaying the natural healing of blood vessels.

The Endothelial Cell (EC) layer is an important component of the normal vessel wall, providing an interface between the blood flow and the tissue surrounding the vessel wall. Endothelial cells are also involved in physiological activities such as angiogenesis, inflammation and prevention of thrombosis. (Rodgers GM. FASEBJ. 1998; 2: 116-123.). Active endothelial cells release a series of VSMC growth or inhibition factors that modulate the stability of the vascular intimal structure. In mature endothelial vessels, endothelium is effective in maintaining VSMC homeostasis. However, when pathological structures are changed, such as when the blood vessel is dilated and torn by a balloon or a stent, the equilibrium state is broken, so that the endothelial VSMC is excessively proliferated, and restenosis caused by endothelial dysfunction is caused.

Endothelial cell growth on the surface of stents has been promoted by local delivery of Vascular Endothelial Growth Factor (VEGF), an endothelial cell mitogen, after stent implantation (CN103566418B), but single-agent delivery has proven to be less effective and produces inconsistent results. Thus, this method is not repeated every time with great precision. Synthetic grafts have also been seeded with endothelial cells, but the clinical efficacy of endothelial seeding is generally poor, most likely because the cells have no adhesion properties to the graft and/or have lost EC function due to ex vivo manipulation. CN105327399 provides a method for constructing an artificial blood vessel, which introduces a prokaryotic system expression vector (Journal of Donghua university (EnglisshEdication), 2012,29: 26-29; Bio-medical materials and engineering,2014,24: 2057) with hydrophilic and negative charge genes and cell adhesion promoting polypeptide genes on the surface, improves the surface hydrophilicity and negative charge, improves the endothelialization potential, is beneficial to tissue healing and anticoagulation, but the technology is suitable for constructing an artificial blood vessel, wherein the used material comprises dacron, and obviously, for the field of vascular stents which need to be degraded after the completion of vascular stenosis treatment, the material has natural non-biological compatibility and can not provide the mechanical support performance required by the vascular stents, and simultaneously, as mentioned above, the proliferation of endothelial cells can cause the formation of vascular restenosis if the steady state can not be maintained.

Therefore, there is a need to provide a stent material for implantation to impart desired biocompatibility, maintain stent support, have a balanced creeping of the EC layer, inhibit restenosis, and restore the self-performance of the blood vessel at a proper time.

Disclosure of Invention

The invention relates to a prosthesis material, in particular to a stent material with biocompatibility, which is more suitable for an intravascular stent material.

The material is provided with a matrix, preferably, the material of the matrix is degradable in a tissue body, and the polymer is polyester, polyanhydride, polyamino acid, polyphosphazene, polysaccharide and the like, and copolymers and mixtures thereof, and comprises one or more of polylactic acid, polyglycolic acid, poly (lactic-glycolic acid), polycaprolactone, chitosan, glucan, chitin, polydecamic anhydride, polyvinyl alcohol and the like, or mixtures thereof; a metal such as iron, magnesium, an iron alloy or a magnesium alloy. The substrate is tubular with tubular inner and outer surfaces that define channels for passage of tissue fluids, such as blood. The surface has structures, such as holes, communicating the inside and outside, which may be circular, oval, rectangular, diamond-shaped, etc.

The communicating inner and outer surface structure is provided with a microcavity, for example, the hole is provided with the microcavity in the cross section direction perpendicular to the axial direction of the matrix body, and the microcavity is loaded with degradable and releasable Fe³⁺Preferably, the substance is a substance which is controllably degradable in the tissue, preferably a composition in the form of microcapsules comprising a degradable polymer as a "shell" and Fe as a "core³⁺Preferably, the water-soluble chelate/complex of (a) is an iron amino acid chelate, such as an iron histidine or cysteine chelate.

The material is provided with short peptide layers which are positioned on the inner surface and the outer surface of a base material, the short peptides can be self-assembled to form hydrogel, and preferably, the sequences of the short peptides on the inner surface and the outer surface are different. The hydrogel formed by self-assembly of the short peptide can be specifically beneficial to the creeping of endothelial cells and the regeneration of endothelial layers.

Base material

The matrix material provided by the invention has biodegradability and excellent biocompatibility. According to the actual application situation, those skilled in the art can know that the scaffold can be completely degraded after the scaffold completes the required supporting function in the body lumen by changing the composition or preparation mode of the matrix material, such as the polymerization degree/molecular weight of the polymer, the composition of the polymer and the metal, the composition of the multilayer degradable material and the like, and the degradation period is controlled to be between 60 days and 24 months.

Micro-cavity

The microcavity needs to be obtained with the holes in the direction of the cross-section of the matrix body perpendicular to the axial direction. It will be appreciated that the microcavities are obtained in the thickness direction of the holes through the stent, i.e. with the plane of their openings in substantially perpendicular relationship to the inner and outer surfaces of the tubular stent. The microcavity has a hemispherical or oval shape or has an ellipsoidal profile, wherein the bottom of the microcavity can be of any shape, in particular a concave or non-concave closed shape. It should be noted that the shape and number of microcavities (e.g., micropores) determine, firstly, the loading of the loaded substance and, secondly, the time taken for release. According to a particular feature, the volume provided by the microcavities (i.e. the volume of each microcavity and thus the total volume provided) can be controlled, predetermined and defined by three parameters that can be used individually or in combination.

The volume control parameters include: (a) the diameter size of the microcavity; (b) the depth and shape of the closed bottom of the microcavities, the purpose of which is to control the depth in order to avoid mechanical weakness and potential cracking or breaking or fissuring in the stent; (c) the total number of microcavities present on the stent.

In the present invention, it is preferable that the average diameter size thereof is in the order of micrometers, for example, 25 to 150 μm, the depth size of the bottom thereof is between 1/5 and 1/3 of the diameter of the hole (the shortest side of the shape if it is a non-hole shape), and the total number of the micro-cavities is more than 20 and less than 80. In one embodiment, the total number of microcavities on a 15mm stent is 30-60.

In the present invention, it is undesirable to have too large a loading capacity and loading density of the loading substance in the microcavity, and to have too deep or too shallow a loading depth resulting in too rapid or too slow release of the loading substance, and it is desirable to have the ability to release the active component therein after a relatively delayed time, which active component can be understood as releasing Fe as described herein³⁺The substance of (1).

Fe released by degradation³⁺Of (2)

The substance is a substance that controllably degrades in the body of a tissue, is a composition obtained in a mixed, miscible or the like form, preferably a composition in the form of microcapsules, comprising a degradable polymer as a "shell" and Fe as a "core"³⁺Preferably, the water-soluble chelate/complex of (a) is an iron amino acid chelate, such as an iron histidine or cysteine chelate.

The degradable polymer is a polymer with controllable degradation, which is well known to those skilled in the art, such as polyester, polyanhydride, polyamino acid, polyphosphazene, polylactic acid, polyglycolic acid, poly (lactic-glycolic acid), polycaprolactone, chitosan, dextran, chitin, polyvinyl alcohol, collagen, gelatin, starch, etc., and the degradation cycle of these polymers can be adjusted by modifying them, controlling molecular weight, concentration, morphology, etc., in a manner well known to those skilled in the art, and will not be described herein again. The degradation period is between 7 days and 3 weeks. Too rapid degradation tends to result in too rapid release of the "core" portion of the material therein to obtain normal formation of the desired tissue, e.g., the endothelial layer, thereby resulting in an increased risk of restenosis, while too slow degradation tends to result in failure of tissue proliferation to maintain homeostasis, which is detrimental to the prevention of restenosis.

Fe³⁺Preferably, the water-soluble chelate/complex of (a) is an iron amino acid chelate, such as an iron histidine or cysteine chelate. It is understood that Fe³⁺The ionic bond formed in the amino acid has weak bonding force and can be inThe high and fast solubility is kept in the pH environment in vivo, so that the Fe is dissolved³⁺Is released in ionic form or has sufficient chemical activity. Wherein, Fe³⁺The water-soluble chelate/complex of (a) is present in the composition in an amount of 0.5 to 2%, preferably 0.8 to 1.5% by weight

Short peptide layer

The short peptide can be self-assembled to form hydrogel, and can be specifically beneficial to the rapid covering of endothelial cells and the regeneration of endothelial layers.

Preferably, the short peptides on the inner and outer surfaces differ in sequence, and the short peptides of different sequences are capable of self-assembly to form a hydrogel, it being understood that the two short peptides can contact each other on a structure having interconnected inner and outer faces.

Two different short peptides were found to be:

sequence 1: (Arg-Ala-Asn-Ala)₄-Arg-Ser-Lys-His-Ala-Lys；

Sequence 2: (Arg-Ala-Asn-Ala)₄-Glu-Asp-Asp-Asp-Glu；

Alternatively, the first and second electrodes may be,

and (3) sequence: (Arg-Ala-Asn-Ala)₄-Glu-Glu-Tyr-Ile-Ser-Ser-Asp；

And (3) sequence 4: (Arg-Ala-Asn-Ala)₄-His-Lys-Lys。

The sequence can be self-assembled in a pH environment in a human body to generate hydrogel, and provides induction and a matrix for the creeping and growth of endothelial cells. As will be appreciated by those skilled in the art, the resulting hydrogel possesses a nanofiber morphology.

However, it is in Fe³⁺In the presence of iron, readily complexed therewith, i.e. Fe³⁺It is understood that the hydrogel formed from the nanofiber morphology gradually disappears its morphology with consumption of peptide molecules capable of aggregating several peptide molecules around it, thereby consuming the nanofiber-forming peptide molecules, and that the hydrogel is in Fe³⁺"degradation" occurs in the presence of the catalyst.

Preferably, the above-mentioned short peptide layer is coated on the surface of the base material to a thickness of 0.5-3mm by a method well known to those skilled in the art.

The invention also relates to the prosthetic material, in particular to a preparation method of a stent material with biocompatibility, more suitable for an intravascular stent material.

The method comprises the following steps:

a matrix material is obtained, said matrix being tubular and having tubular inner and outer surfaces, the inner surface constituting a passage for tissue fluid, such as blood, to pass through. The surface is provided with a structure for communicating the inside and the outside, such as holes, and the holes can be round, oval, rectangular, rhombic and the like;

obtaining microcavities in the thickness direction of the above holes through the stent, using known techniques, such as laser engraving, microetching techniques; preferably, the microcavities have a hemispherical or oval shape or have an ellipsoidal profile with an average diameter dimension on the order of microns, e.g., 25-150 μm, and a depth dimension at the base between 1/5-1/3 of the diameter of the aperture (or shortest side of the shape if non-aperture), and the total number of microcavities is greater than 20 and less than 80. In one embodiment, the total number of microcavities on a 15mm stent is 30-60;

obtained in mixed, miscible or the like form, preferably in the form of a microcapsule, comprising a degradable polymer as "shell" and Fe as "core³⁺Preferably, the water-soluble chelate/complex of (a) is an iron amino acid chelate, such as an iron histidine or cysteine chelate. The degradable polymer is a polymer with controllable degradation, which is well known to those skilled in the art, such as polyester, polyanhydride, polyamino acid, polyphosphazene, polylactic acid, polyglycolic acid, poly (lactic-glycolic acid), polycaprolactone, chitosan, dextran, chitin, polyvinyl alcohol, collagen, gelatin, starch, etc., and the degradation cycle is between 7 days and 3 weeks, preferably between 10 days and 2 weeks. Wherein, Fe³⁺The water-soluble chelate/complex of (a) is present in the composition in an amount of 0.5 to 2% by weight, preferably 0.8 to 1.5% by weight;

the microcavities are loaded with the above-mentioned composition, in which Fe is present, by known techniques, such as dipping, spraying, ink-jetting or atomization³⁺Of water-soluble chelates/complexes ofThe loading is 4-15 mug, preferably 5-10 mug, per mm of axial length of the prosthesis;

respectively coating short peptide coatings on two surfaces of the substrate by using a known technology, such as a dipping, spraying, atomizing or ink-jetting technology, preferably, the sequences of the short peptides on the inner surface and the outer surface are different, and the two short peptides can be contacted with each other, preferably, on a structure with communicated inner surfaces and outer surfaces; in one embodiment, the short peptide coating further comprises an active ingredient, such as rapamycin, paclitaxel, sirolimus, VEGF, dexamethasone, or a combination thereof, and the like, preferably dexamethasone, so as to delay the disappearance of the hydrogel structure.

Technical effects

According to the invention, through self-assembly of the short peptide coating, specific hydrogel which is beneficial to rapid creeping of endothelial cells and regeneration of endothelial layers is formed on the surface of the prosthesis, and the hydrogel can release Fe in a microcavity structure of the prosthesis³⁺The water-soluble chelate/complex then gradually undergoes structural disappearance/degradation, thereby restoring the balanced growth of the tissue, particularly the endothelial layer, and avoiding restenosis caused by endothelial dysfunction. Therefore, the prosthesis of the present invention can endow the prosthesis with required biocompatibility, maintain the support force of the stent, simultaneously have the balance creeping of the EC layer, inhibit restenosis, and timely restore the self-performance of tissues, especially blood vessels.

One skilled in the art will readily appreciate that the present invention may be used to perform a variety of treatments within an individual. Further objects, features and advantages of the present invention will become apparent from the following illustrative description, with reference to a number of examples or embodiments of the invention, which are given purely by way of illustration and do not in any way limit the scope of the invention.

Examples

Example 1

Preparation of a prosthesis (preferably an intravascular stent) with microcavities and short peptide coatings

Step 1: obtaining a base material of the prosthesis, which can degrade a tubular material of pure iron and make it have holes on the surface communicating the inside and the outside;

step 2: obtaining microcavities in the thickness direction of the holes through the prosthesis by means of laser engraving; the microcavities have a hemispherical profile with a diameter dimension of 30 μm, a bottom depth dimension of 1/3 times the diameter of the holes, and a total number of 30 microcavities;

and step 3: obtaining a composition in the form of microcapsules, using conventional techniques, said composition comprising gelatin as a "shell" and iron histidine chelate as a "core", wherein the iron histidine chelate is present in the composition in an amount of 0.5% by weight, and the gelatin has a degradation period of about 7 days;

and 4, step 4: loading the composition in the microcavity using a spray coating process, wherein the loading of histidine-chelated iron is 4 μ g per mm of axial length of the prosthesis;

and 5: respectively coating short peptide coatings on two surfaces of the substrate by using a dipping process, wherein the two short peptides can be in contact with each other, and the sequences of the two short peptides are the sequence 1 and the sequence 2 respectively;

and 5: drying, sterilizing and packaging to obtain the prosthetic material.

Example 2

The procedure was the same as in example 1, except that: the matrix material adopted in the step 1 is degradable polycaprolactone; in the step 2, the diameter of the micro-cavity is 50 μm, the depth of the bottom is 1/4 of the diameter of the hole, and the total number of the micro-cavities is 40; in the step 3, the shell is chitosan, the degradation period is about 1 week, the core is cysteine chelated iron, and the weight content of the core in the composition is 0.8%; the loading in step 4 was 8. mu.g.

Example 3

The procedure was the same as in example 1, except that: the matrix material adopted in the step 1 is degradable pure magnesium; in step 2, the diameter of the micro-cavity is 100 μm, the depth of the bottom is 1/5 of the diameter of the hole, and the total number of the micro-cavities is 60; in the step 3, the shell is collagen, the degradation period is about 2 weeks, the core is cysteine chelated iron, and the weight content of the core in the composition is 1.5%; the loading amount in the step 4 is 10 mu g; the sequences of the two short peptides in step 5 are sequence 3 and sequence 4, respectively, as described above.

Example 4

The procedure was the same as in example 1, except that: the matrix material adopted in the step 1 is a mixture of polycaprolactone and chitosan; in the step 2, the diameter of the micro-cavities is 150 μm, and the total number of the micro-cavities is 80; in the step 3, the shell is poly (lactic acid-glycolic acid), the degradation period is about 3 weeks, and the weight content of the core in the composition is 2%; the loading amount in the step 4 is 15 mu g; the sequences of the two short peptides in step 5 are sequence 3 and sequence 4, respectively, as described above.

Example 5

The procedure was the same as in example 1, except that: in the step 5, the coating layer of the short peptide contains dexamethasone with the weight content of 0.2-0.6%.

Example 6

The procedure was the same as in example 1, except that: and in the step 5, the rapamycin with the weight content of 0.2-0.6% is contained in the coating layer of the short peptide.

Comparative example 1

The procedure is analogous to example 1, except that: there is no step 5, i.e. no short peptide coating applied.

Comparative example 2

The procedure is analogous to example 1, except that: there are no steps 2-4, i.e. there is no composition in the form of microcavities and microcapsules.

Comparative example 3

The procedure is analogous to example 1, except that: in step 2, the diameter of the microcavity is 30 μm, the depth of the bottom is 1/8 of the diameter of the hole, and the total number of the microcavities is 80.

Comparative example 4

The procedure is analogous to example 1, except that: in step 2, the diameter of the microcavity is 200 μm, the depth of the bottom is 1/4 of the diameter of the hole, and the total number of the microcavities is 120.

Comparative example 5

The procedure is analogous to example 1, except that: in step 2, the diameter of the microcavity is 40 μm, the depth of the bottom is 1/2 of the diameter of the hole, and the total number of the microcavities is 50.

Comparative example 6

The procedure is analogous to example 1, except that: in the step 3, the shell is poly (L-lactide), and the degradation period is about 45 days.

Comparative example 7

The procedure is analogous to example 1, except that: in the step 3, the shell is oxidized cellulose, and the degradation period is about 5 days.

Comparative example 8

The procedure is analogous to example 1, except that: the loading in step 4 was 1 μ g per mm of axial length of the prosthesis.

Comparative example 9

The procedure is analogous to example 1, except that: the loading in step 4 was 30 μ g per mm of axial length of the prosthesis.

In vitro cell culture experiments

3-6 generations are taken after the expansion and passage of the transgenic endothelial cells, and the concentration is 3 multiplied by 10⁴cell/ml and simulated tissue body fluid were used to cyclically and continuously perfuse the stent samples prepared in the examples and comparative examples, the flow rate in the sample cavity was controlled to gradually increase from 0.033 to 0.1ml/s, and the corresponding shear stress at the vessel wall was about 1X 10^-2N/m²To 4X 10^-2N/m²Meanwhile, the circulation continuous perfusion lasts for 1 month, the endothelialization degree of the cells is observed through the detection of an optical lens, an electron microscope and silver staining, the condition that endothelial cells secrete extracellular matrix is displayed by a fluorescence microscope, and the result is shown in table 1.

TABLE 1

The experiments show that the surface of the stent is endothelialized successfully under the preparation process condition of the invention, and endothelial cells can secrete extracellular matrix, which indicates that the endothelial cells can grow normally on the surface of the stent. But the endothelial cell growth on the surface of the stent in the comparative example was not ideal.

Animal experiments

Establishing a stent implantation model:

the small healthy pigs of three months old are fed with aspirin (300mg/d) and clopidogrel (75mg/d) every day from 3 days before operation, and are fasted and forbidden for 10 hours.

Performing intramuscular injection anesthesia with Lumiannin II at a dose of 0.05ml/kg, fixing the animal in operating table after anesthesia, establishing venous access, trachea cannula and breathing machine assisted respiration

Sequentially cutting skin and muscle tissues, ligating small blood vessels, stripping femoral artery blood vessels, injecting heparin (1mg/Kg of body weight) into veins, clamping the proximal end and the distal end of the femoral artery by vascular clamps respectively to block blood flow, longitudinally cutting a 1cm incision at the femoral artery part for blocking the blood flow, cutting the stents prepared in the sterilized examples and comparative examples along the femoral artery, placing the stents into a femoral artery stent, and selecting the proximal section of the blood vessel as a stent implantation part in the implantation process to avoid branch blood vessels as much as possible. The ratio of the stent to the vessel diameter is 1.1-1.2: 1, a vessel incision is sutured by using a vessel suture, after a near-end and a far-end vascular clamp are loosened, whether blood seeps from an anastomotic stoma is carefully observed, muscle tissues and skin are sutured layer by layer after the blood seeps are determined, the surface of the skin is coated with iodophors, and the skin is bound by sterile gauze. After operation, the animals are injected with penicillin 80 ten thousand U for 3d to prevent infection and are normally raised.

The above examples and comparative examples were each carried out by taking 5 samples, and the following results were average values.

After 2 months, the pigs were euthanized, the stents in the vessels were extracted, paraffin sections with a thickness of 5 μm were made, images were taken and edited in a computer image analysis system to obtain the percentage of luminal stenosis, hematoxylin-eosin (HE) staining was used to observe the status of capillaries in the vessel thrombus, intima, adventitia media, immunofluorescence staining was used to observe the status of endothelial cells, smooth muscle cells, and the results are shown in table 2.

TABLE 2

The experiments show that compared with a comparison group, the stent has high patency rate, no thrombosis and intimal hyperplasia, capillaries appear in the adventitia and autologous endothelialization is successfully formed, and the stent gradually recovers the structure and the function similar to those of a normal blood vessel after being implanted.

Claims

1. A biocompatible endoprosthesis material for achieving balanced epithelial cell layer coverage to inhibit restenosis, comprising:

matrix: the matrix is made of a degradable tissue body, is tubular and is provided with tubular inner and outer surfaces, the inner surface forms a channel for tissue fluid to pass through, the surface is provided with a structure communicated with the inner surface and the outer surface, and the structure is a hole;

microcavity: the micro-cavity is obtained in the cross section direction of the hole on the matrix body, which is vertical to the axial direction, the micro-cavity is located in the thickness direction of the hole, and the plane of the opening of the micro-cavity is vertical to the inner surface and the outer surface of the tubular support;

composition (A): loaded in the micro-cavity and can degrade to release Fe³⁺Said composition being in the form of microcapsules comprising a degradable polymer as "shell", said degradable polymer having a degradation period of between 7 days and 3 weeks, and Fe as "core³⁺Water-soluble chelates/complexes of (a);

short peptide layer: the short peptide layer is positioned on the inner surface and the outer surface of the matrix material, the short peptides can be self-assembled to form hydrogel, and the hydrogel formed after the short peptides are self-assembled can be specifically beneficial to the creeping covering of endothelial cells and the regeneration of an endothelial layer;

wherein the composition is capable of releasing the "core" during degradation, allowing it to complex with the hydrogel, thereby allowing the hydrogel to gradually lose its form.

2. A prosthetic material as claimed in claim 1 wherein: the material of the matrix is selected from polymer or metal, wherein the polymer is selected from one or more of polylactic acid, polyglycolic acid, poly (lactic-glycolic acid), polycaprolactone, chitosan, dextran, chitin, polydecamic anhydride, polyvinyl alcohol or a mixture thereof, and the metal is selected from one of iron, magnesium, iron alloy or magnesium alloy.

3. A prosthetic material according to claim 1 or 2, wherein: the average diameter dimension of the microcavities is 25-150 μm, the depth dimension of the bottom is between 1/5-1/3 of the pore diameter, and the total number of microcavities is greater than 20 and less than 80.

4. A prosthetic material as claimed in claim 3, wherein: fe in the composition³⁺The content of the water-soluble chelate/complex in the composition is 0.5-2% by weight.

5. A prosthetic material according to claim 4, wherein: the degradable polymer as the 'shell' is selected from one or more of polylactic acid, polyglycolic acid, poly (lactic-glycolic acid), polycaprolactone, chitosan, glucan, chitin, polyvinyl alcohol, collagen, gelatin and starch; said Fe as a "nucleus³⁺The water-soluble chelate/complex of (a) is an amino acid chelated iron, said Fe³⁺The loading of the water-soluble chelate/complex of (a) is 4-15 μ g per mm of axial length of the prosthesis.

6. A prosthetic material as claimed in claim 3, wherein: the short peptides on the inner and outer surfaces have different sequences, and the two short peptides can contact each other on a structure with communicated inner and outer surfaces.

7. A prosthetic material according to claim 6, wherein: the two different short peptides were:

sequence 1: (Arg-Ala-Asn-Ala)₄-Arg-Ser-Lys-His-Ala-Lys；

Sequence 2: (Arg-Ala-Asn-Ala)₄-Glu-Asp-Asp-Asp-Glu；

Alternatively, the first and second electrodes may be,

and (3) sequence: (Arg-Ala-Asn-Ala)₄-Glu-Glu-Tyr-Ile-Ser-Ser-Asp；

And (3) sequence 4: (Arg-Ala-Asn-Ala)₄-His-Lys-Lys。

8. A prosthetic material as claimed in claim 7, wherein: the short peptide layer forms a thickness of 0.5-3mm on the surface of the base material, and the short peptide coating also contains active ingredients selected from rapamycin, paclitaxel, sirolimus, VEGF, dexamethasone or a combination of the rapamycin, the paclitaxel, the sirolimus, the VEGF and the dexamethasone.

9. A method of preparing a prosthetic material for achieving balanced epithelial cell layer coverage to inhibit restenosis as claimed in any one of claims 1-8, comprising:

obtaining a substrate material, wherein the substrate is tubular and is provided with tubular inner and outer surfaces, the inner surface forms a channel for tissue fluid to pass through, the surface is provided with holes communicated with the inner surface and the outer surface, and the holes are round, oval, rectangular or rhombic;

obtaining microcavities in the thickness direction of the holes through the stent; said microcavities having a hemispherical or oval shape or having an ellipsoidal profile with an average diameter dimension of 25-150 μm, a depth dimension of the base between 1/5-1/3 of the diameter of said pores, and the total number of said microcavities being greater than 20 and less than 80;

obtaining a microcapsule form in a mixed or miscible formThe composition comprising a degradable polymer as a "shell" and Fe as a "core³⁺Water-soluble chelates/complexes of (a); said Fe³⁺The water-soluble chelate/complex of (a) is an amino acid chelated iron; the degradable polymer is selected from one or more of polylactic acid, polyglycolic acid, poly (lactic-glycolic acid), polycaprolactone, chitosan, glucan, chitin, polyvinyl alcohol, collagen, gelatin and starch, and the degradation cycle is between 7 days and 3 weeks; fe³⁺The content of the water-soluble chelate/complex in the composition is 0.5-2% by weight;

supporting in said microcavities the above composition wherein Fe³⁺The loading of the water-soluble chelate/complex of (a) is 4-15 μ g per mm of axial length of the prosthesis;

and respectively coating short peptide coatings on two surfaces of the substrate, wherein the short peptides on the inner surface and the outer surface are mutually contacted on a structure with communicated inner and outer surfaces.

10. Use of the prosthetic material according to any one of claims 1-8 for the preparation of an endoprosthesis.