Stent based on all-drug-based structure and function integrated composite coating and preparation method and application thereof

Abstract

The invention discloses a stent based on a full-drug-based structure function integrated composite coating and a preparation method and application thereof, and belongs to the technical field of medical instruments.The stent comprises a stent body, tannic acid coatings and EP-C9 polypeptide coatings are sequentially arranged on the outer surface of the stent body from inside to outside, the tannic acid coatings and the EP-C9 polypeptide coatings are alternately arranged, and the tannic acid coatings and the EP-C9 polypeptide coatings are sequentially arranged on the outer surface of the stent body from inside to outside. One tannic acid coating and one EP-C9 polypeptide coating are marked as one group, N groups are arranged in total, and N is greater than or equal to 1. The stent has excellent antithrombotic and anti-inflammatory functions and has no carrier residue side effect, components of the coating are functional molecules and structural molecules and are completely absorbed by a body after playing pharmacological action, and the problem that a traditional stent has inflammation and thrombus risks is fundamentally solved.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, specifically relating to a scaffold based on a fully drug-based structural-functional integrated composite coating, its preparation method, and its application. Background Technology

[0002] Stent implantation is an important treatment for cerebral vascular stenosis, and currently, bare-metal stents are the main type used clinically. However, bare-metal stents are prone to causing intimal hyperplasia after implantation, leading to a high long-term restenosis rate, which greatly limits their clinical application. To reduce the restenosis rate, drug-eluting stents have emerged. Local thrombosis-inflammation after drug-eluting stent implantation is the main mechanism of restenosis. An ideal cerebral vascular stent should have synergistic antithrombotic and anti-inflammatory capabilities, while avoiding long-term adverse reactions caused by residual coating materials. Specific problems are as follows: First, existing drug-eluting stents use polymers such as polylactic acid (PLA) and polylactic acid-glycolic acid copolymer (PLA-glycolic acid copolymer) as drug carriers. These polymers remain in the vascular area for a long time after drug release, and their degradation products can induce persistent inflammatory reactions, allergic reactions, and late thrombosis. PLA takes 12-24 months to completely degrade, and acidic products are generated during the degradation process, further aggravating the local inflammatory environment.

[0003] Second, single-function coatings cannot simultaneously address the dual challenges of thrombosis and inflammatory response. Existing coating technologies often focus on a single function: anti-proliferation or anti-thrombosis. However, the pathological process after stent placement involves multiple related links such as platelet activation, inflammatory cell infiltration, smooth muscle cell proliferation, and delayed endothelial repair. Single-function coatings cannot fully address this complex pathophysiological process, resulting in the continued existence of restenosis and thrombosis risks.

[0004] Third, existing coating technologies are complex to construct and lack stability; traditional covalent grafting methods have harsh reaction conditions that may damage the structure and function of living molecules. At the same time, physical adsorption methods have problems such as low loading capacity and uncontrollable release kinetics, resulting in poor coating stability and premature release of functional molecules that cannot play a sustained role.

[0005] Fourth, there is a contradiction between promoting endothelial healing and controlling smooth muscle proliferation. Antiproliferative drugs, while inhibiting smooth muscle cell proliferation, also delay endothelial cell repair, damage the endothelial barrier function, and increase the risk of late thrombosis. There is a lack of effective strategies in the current technology that can simultaneously promote endothelialization and inhibit smooth muscle cell proliferation. Summary of the Invention

[0006] To address the aforementioned shortcomings in existing technologies, this invention provides a stent based on a fully drug-based structural-functional integrated composite coating, its preparation method, and its application. This stent possesses excellent antithrombotic and anti-inflammatory functions, and has no carrier residue side effects. The components of the coating are both functional and structural molecules, and are completely absorbed by the body after exerting their pharmacological effects, fundamentally solving the risks of inflammation and thrombosis associated with traditional stents.

[0007] To achieve the above objectives, the technical solution adopted by the present invention to solve its technical problem is as follows:

[0008] A scaffold based on a fully drug-based structural-functional integrated composite coating includes a scaffold body. The outer surface of the scaffold body is sequentially coated with a tannic acid coating and an EP-C9 peptide coating from the inside out. The tannic acid coating and the EP-C9 peptide coating are alternately arranged. One layer of tannic acid coating and one layer of EP-C9 peptide coating are marked as a group, and a total of N groups are arranged, where N≥1.

[0009] Furthermore, N = 2 - 4.

[0010] Furthermore, the stent body is a cobalt-chromium alloy stent.

[0011] The above-mentioned method for preparing a scaffold based on a fully drug-based structural-functional integrated composite coating includes the following steps:

[0012] (1) Constructing a tannic acid base coating: The clean scaffold body is subjected to hydrophilic modification treatment, and then the scaffold body is immersed in a tannic acid solution to construct a tannic acid base coating on the surface of the scaffold body.

[0013] (2) Construction of peptide coating: The scaffold body for constructing tannic acid base coating was immersed in EP-C9 mixed peptide solution and EP-C9 composite peptide coating was constructed on its surface.

[0014] (3) Repeated coating construction: Repeat the operations in steps (1) and (2) to construct multiple sets of coatings on the surface of the support body;

[0015] (4) Curing: Finally, the stent body is dried, cured, and sterilized.

[0016] Furthermore, the specific method for hydrophilic modification treatment in step (1) is as follows: place the support body in an oxygen plasma cleaner with a power of 100W and an oxygen flow rate of 20sccm for 10-20 minutes.

[0017] Furthermore, in step (1), the concentration of the tannic acid solution is 1-2 mg / ml, the pH value of the solution is 5.5-6.0, the immersion temperature is 36-38℃, and the immersion time is 30-45 min.

[0018] Further, in step (2), the molar ratio of EP to C9 in the EP-C9 mixed polypeptide solution is 1:1, the total polypeptide concentration is 0.5-1 mg / ml, the solution pH is 7.2-7.4, the immersion temperature is 24-26℃, and the immersion time is 30-45 min.

[0019] Furthermore, when the stent body is transferred from one solution to another, the stent body is rinsed 2-4 times, each time for 1-2 minutes.

[0020] Furthermore, in step (4), the product is dried for 12 hours in a sterile, room temperature environment.

[0021] The above-mentioned stent based on a fully drug-based structural-functional integrated composite coating is used in the preparation of materials for cerebral vascular stenosis.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. This invention utilizes multiple non-covalent interactions (hydrogen bonds, π-π stacking, hydrophobic interactions, and electrostatic interactions) between tannic acid and polypeptide molecules to construct a biomimetic coating with a stable three-dimensional network structure, providing an ideal platform for the synergistic release of antithrombotic molecules and anti-inflammatory polypeptides. The polyphenolic hydroxyl groups of tannic acid form a broad intermolecular interaction network with the amino and carboxyl functional groups of polypeptide molecules, enabling the coating to maintain a stable structure in the physiological environment (de-slippage rate after ultrasound <8%). Simultaneously, it achieves controlled release of epitubatide over 7-10 days and sustained release of C9 polypeptide over 14-21 days, with a burst release rate of less than 15%. This solves the problems of severe burst release (>60%) in traditional physical adsorption coatings and excessively slow release (<40% after 30 days) in covalently grafted coatings.

[0024] 2. The "tannic acid-peptide" composite coating constructed using layer-by-layer self-assembly technology in this invention achieves precise loading and controllable release of functional molecules, significantly improving the biological performance of the scaffold. By adjusting the tannic acid concentration, peptide ratio, and number of assembled layers, the coating thickness can be precisely controlled within the range of 200-500 nm, and the drug loading capacity can reach EP 50-200 μg / cm³. 2 C930-150μg / cm 2 The EP loading efficiency reached over 85%, and the C9 loading efficiency reached over 80%. In vitro experiments showed that the coating significantly reduced platelet adhesion density and macrophage TNF-α release.

[0025] 3. The fully biodegradable nature of the tannic acid substrate in this invention completely solves the long-term safety problem caused by carrier residue in traditional coatings. Compared with traditional PLA / PLGA coatings, which still have 35-40% carrier residue after 180 days, the tannic acid coating is completely degradable with no carrier residue. Animal experiments show a significant reduction in the incidence of late thrombosis. Simultaneously, the antioxidant and anti-inflammatory properties of tannic acid itself, combined with the C9 peptide, form a synergistic anti-inflammatory effect, further enhancing the anti-inflammatory performance of the stent.

[0026] 4. This invention innovatively resolves the contradiction between inhibiting smooth muscle proliferation and promoting endothelial healing, achieving a "selective inhibition" function. Animal experiments show that the stent of this invention significantly reduces the restenosis rate while achieving greater endothelialization coverage and shortening the time to complete endothelialization, thus solving the clinical problem of rapamycin-like drugs inhibiting smooth muscle proliferation while simultaneously delaying endothelial healing.

[0027] 5. The preparation process in this invention is simple and economical, with promising prospects for clinical translation. Compared to the traditional covalent grafting method (cost $120-150 / stent), this invention uses a solution impregnation method under normal temperature and pressure, eliminating the need for expensive crosslinking agents and special equipment, reducing the cost to $45-60 / stent, and increasing the yield to over 92%. Simultaneously, the coating exhibits excellent biocompatibility; cytotoxicity tests show a cell viability rate of 96.8%, far below national standards.

[0028] 6. This invention has successfully developed a multifunctional cerebral vascular stent coating with excellent anti-thrombotic, anti-inflammatory, endothelial repair-promoting, and smooth muscle proliferation-inhibiting properties through innovative polyphenol-peptide self-assembly technology. It also solves the long-term safety problems of traditional coating carrier residue and late thrombosis. It is significantly superior to existing technologies in terms of performance indicators and production costs, and has important clinical translational value and market application prospects. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the chemical composition of the coating on the surface of the support.

[0030] Figure 2 A statistical graph showing the changes in EP and C9 on the scaffold surface over metabolic time;

[0031] Figure 3 Statistical graph of the number of endothelial cells on the surface of different scaffolds at different times;

[0032] Figure 4 Statistical graph of the number of smooth muscle cells on the surface of different scaffolds at different times;

[0033] Figure 5 Scanning electron microscope images of different support surfaces;

[0034] Figure 6 A statistical graph showing the release of inflammatory factors from the supernatant of THP-1 cells in different scaffold groups;

[0035] Figure 7 The left image is a schematic diagram of the in vivo experiment, and the right image is a sample of different scaffolds after 1 hour of cycling. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments.

[0037] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0038] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0039] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0040] Example 1

[0041] A scaffold based on a fully drug-based structural-functional integrated composite coating (EP-C9-TA) includes a cobalt-chromium alloy (L605) scaffold body with a diameter of 3.5 mm and a length of 15 mm. The outer surface of the scaffold body is provided with a tannic acid coating and an EP-C9 peptide coating from the inside out. The tannic acid coating and the EP-C9 peptide coating are alternately arranged. One layer of tannic acid coating and one layer of EP-C9 peptide coating are marked as a group, and a total of 4 groups are arranged.

[0042] The preparation method of the above-mentioned stent is as follows:

[0043] (1) Cleaning and pretreatment of the stent body: The cobalt-chromium alloy stent body was ultrasonically cleaned in acetone, anhydrous ethanol and ultrapure water for 15 minutes each (power 300W) to thoroughly remove surface grease and contaminants; after drying with sterile nitrogen, it was placed in an oxygen plasma cleaner (power 100W, oxygen flow rate 20sccm) for 15 minutes to improve surface hydrophilicity and activity, thereby achieving hydrophilic modification treatment of the clean stent body;

[0044] (2) Preparation of coating solution: Add tannic acid to PBS solution with pH 5.5 to prepare a tannic acid stock solution with a concentration of 1.5 mg / ml. Filter the solution through a 0.22 μm microporous membrane for sterilization and set aside for later use.

[0045] Eptibatide (EP) and C9 peptide stock solutions with a concentration of 1.0 mg / ml were prepared using sterile ultrapure water and stored at -80℃ for later use. Before use, the EP stock solution and C9 stock solution were mixed at a molar ratio of 1:1 and diluted with PBS (pH 7.4) to a total peptide concentration of 0.6 mg / ml to obtain an EP-C9 mixed peptide solution.

[0046] (3) Construction of tannic acid base coating: The treated scaffold body was placed in tannic acid solution (1.5 mg / ml, pH 5.5) and reacted in a constant temperature shaker (50 rpm) at 37℃ for 30 min to construct a tannic acid base coating on the surface of the scaffold body. Then the scaffold was removed and gently rinsed 3 times with a mixture of ethanol and water at a volume ratio of (1:9) for 1 min each time to remove TA molecules that are not physically adsorbed.

[0047] (4) Construction of peptide coating: The scaffold body for constructing tannic acid base coating was placed in EP-C9 mixed peptide solution (total peptide concentration of 0.6 mg / ml, pH 7.4) and reacted at 25°C with shaking (30 rpm) for 45 min. The EP-C9 peptide coating was then constructed on its surface. The scaffold was then removed and gently rinsed twice with PBS (pH 7.4) for 2 min each time to remove unbound peptides.

[0048] (5) Repeat the coating construction: Repeat the operations in steps (2) and (3) to construct 4 sets of coatings on the surface of the support body;

[0049] (6) Curing: The coated scaffold was dried at room temperature in a sterile laminar flow hood for 12 hours. Finally, it was sterilized by low-dose gamma ray (20kGy), sealed and stored at 4℃ to obtain the EP-C9-TA scaffold.

[0050] Example 2

[0051] A scaffold based on a fully drug-based structural-functional integrated composite coating (EP-C9-TA) includes a cobalt-chromium alloy (L605) scaffold body with a diameter of 3.5 mm and a length of 15 mm. The outer surface of the scaffold body is provided with a tannic acid coating and an EP-C9 peptide coating from the inside out. The tannic acid coating and the EP-C9 peptide coating are alternately arranged. One layer of tannic acid coating and one layer of EP-C9 peptide coating are marked as a group, and a total of 3 groups are arranged.

[0052] The preparation method of the above-mentioned stent is as follows:

[0053] (1) Cleaning and pretreatment of the stent body: The cobalt-chromium alloy stent body was ultrasonically cleaned in acetone, anhydrous ethanol and ultrapure water for 15 minutes each (power 300W) to thoroughly remove surface grease and contaminants; after drying with sterile nitrogen, it was placed in an oxygen plasma cleaner (power 100W, oxygen flow rate 20sccm) for 15 minutes to improve surface hydrophilicity and activity, thereby achieving hydrophilic modification treatment of the clean stent body;

[0054] (2) Preparation of coating solution: Add tannic acid to PBS solution with pH 6.0 to prepare tannic acid stock solution with a concentration of 1 mg / ml. Filter the solution through a 0.22 μm microporous membrane for sterilization and use.

[0055] Eptibatide (EP) and C9 peptide stock solutions with a concentration of 1.0 mg / ml were prepared using sterile ultrapure water and stored at -80℃ for later use. Before use, the EP stock solution and C9 stock solution were mixed at a molar ratio of 1:1 and diluted with PBS (pH 7.2) to a total peptide concentration of 0.8 mg / ml to obtain an EP-C9 mixed peptide solution.

[0056] (3) Construction of tannic acid base coating: The treated scaffold body was placed in tannic acid solution (1 mg / ml, pH 6.0) and reacted in a constant temperature shaker (50 rpm) at 36℃ for 45 min to construct a tannic acid base coating on the surface of the scaffold body. Then the scaffold was removed and gently rinsed 3 times with a mixture of ethanol and water at a volume ratio of (1:9) for 1 min each time to remove TA molecules that are not physically adsorbed.

[0057] (4) Construction of peptide coating: The scaffold body for constructing tannic acid base coating was placed in EP-C9 mixed peptide solution (total peptide concentration of 0.8 mg / ml, pH 7.2) and reacted at 24℃ with shaking (30 rpm) for 45 min. The EP-C9 peptide coating was then constructed on its surface. The scaffold was then removed and gently rinsed twice with PBS (pH 7.2) for 2 min each time to remove unbound peptides.

[0058] (5) Repeat the coating construction: Repeat the operations in steps (2) and (3) to construct 3 sets of coatings on the surface of the support body;

[0059] (6) Curing: The coated scaffold was dried at room temperature in a sterile laminar flow hood for 12 hours. Finally, it was sterilized by low-dose gamma ray (20kGy), sealed and stored at 4℃ to obtain the EP-C9-TA scaffold.

[0060] Example 3

[0061] A scaffold based on a fully drug-based structural-functional integrated composite coating (EP-C9-TA) includes a cobalt-chromium alloy (L605) scaffold body with a diameter of 3.5 mm and a length of 15 mm. The outer surface of the scaffold body is provided with a tannic acid coating and an EP-C9 peptide coating from the inside out. The tannic acid coating and the EP-C9 peptide coating are alternately arranged. One layer of tannic acid coating and one layer of EP-C9 peptide coating are marked as a group, and a total of 3 groups are arranged.

[0062] The preparation method of the above-mentioned stent is as follows:

[0063] (1) Cleaning and pretreatment of the stent body: The cobalt-chromium alloy stent body was ultrasonically cleaned in acetone, anhydrous ethanol and ultrapure water for 15 minutes each (power 300W) to thoroughly remove surface grease and contaminants; after drying with sterile nitrogen, it was placed in an oxygen plasma cleaner (power 100W, oxygen flow rate 20sccm) for 15 minutes to improve surface hydrophilicity and activity, thereby achieving hydrophilic modification treatment of the clean stent body;

[0064] (2) Preparation of coating solution: Add tannic acid to PBS solution with pH 5.8 to prepare tannic acid stock solution with a concentration of 2 mg / ml. Filter the solution through a 0.22 μm microporous membrane for sterilization and use.

[0065] Eptibatide (EP) and C9 peptide stock solutions with a concentration of 1.0 mg / ml were prepared using sterile ultrapure water and stored at -80℃ for later use. Before use, the EP stock solution and C9 stock solution were mixed at a molar ratio of 1:1 and diluted with PBS (pH 7.3) to a total peptide concentration of 1 mg / ml to obtain an EP-C9 mixed peptide solution.

[0066] (3) Construction of tannic acid base coating: The treated scaffold body was placed in tannic acid solution (2mg / ml, pH5.8) and reacted in a constant temperature shaker (50rpm) at 38℃ for 40min to construct a tannic acid base coating on the surface of the scaffold body. Then the scaffold was removed and gently rinsed 3 times with a mixture of ethanol-water solution (volume ratio 1:9) for 1min each time to remove TA molecules that are not physically adsorbed.

[0067] (4) Construction of peptide coating: The scaffold body for constructing tannic acid base coating was placed in EP-C9 mixed peptide solution (total peptide concentration of 1 mg / ml, pH 7.3) and reacted at 26℃ with shaking (30 rpm) for 40 min. The EP-C9 peptide coating was then constructed on its surface. The scaffold was then removed and gently rinsed twice with PBS (pH 7.3) for 2 min each time to remove unbound peptides.

[0068] (5) Repeat the coating construction: Repeat the operations in steps (2) and (3) to construct 3 sets of coatings on the surface of the support body;

[0069] (6) Curing: The coated scaffold was dried at room temperature in a sterile laminar flow hood for 12 hours. Finally, it was sterilized by low-dose gamma ray (20kGy), sealed and stored at 4℃ to obtain the EP-C9-TA scaffold.

[0070] Test case

[0071] Taking the EP-C9-TA stent prepared in Example 1 as an example, its performance was tested as follows:

[0072] 1. Performance test results

[0073] Figure 1 This is a schematic diagram of the chemical composition of the coating on the surface of the support.

[0074] Drug loading (HPLC determination): After 3 cycles of assembly, the drug loading per unit surface area of ​​the stent was: EP (158.4±12.7) μg / cm³. 2 C9(102.3±9.8)μg / cm 2 The load efficiencies reached 88.5% and 85.3%, respectively.

[0075] In vitro release kinetics (PBS, 37℃): The absorbance was measured using a UV-Vis spectrophotometer, and the surface phenol (or quinone) functional group density was calculated using a standard curve, thus indirectly determining the coating's stability. Figure 2 It can be seen that as time increases, the amount of material on the coating surface gradually decreases, indicating a certain degree of release. EP has a rapid initial release (about 25%) within 1 day, followed by a continuous release phase, with a cumulative release rate of 92.5% after 7 days. C9 release is slower and more stable, with a cumulative release rate of 88.7% after 21 days, and no obvious burst release phenomenon, indicating that the coating structure is stable.

[0076] 2. In vitro biological performance evaluation

[0077] This was used to evaluate the anticoagulant, anti-inflammatory, endothelial repair-promoting, and smooth muscle proliferation-enhancing capabilities of the EP-C9-TA coated stent under in vitro conditions.

[0078] Experimental conditions and methods:

[0079] ① Cell culture: Human umbilical vein endothelial cells (HUVEC), human aortic smooth muscle cells (HASMC), and macrophages derived from THP-1 were cultured at 37°C and 5% CO2 using the corresponding complete culture medium.

[0080] ② Experimental groups: CoCr alloy sheet (CoCr group); Tannic acid coated CoCr alloy sheet (TA group); CoCr alloy sheet with EP-C9 coating superimposed on TA (EP-C9 group); CoCr alloy sheet with TA-EP-C9 coating superimposed on EP-C9 group (EP-C9# group).

[0081] ③ Anticoagulation assay (Chandler-loop system): Each group of stents (n=5) was inserted into a silicone tube filled with 4 mL of fresh anticoagulated blood from healthy individuals, and the tubes were sealed to form a loop. The loop was fixed on a rotating disk and circulated in a 37°C constant temperature water bath at 15 rpm for 2 hours. After the experiment, the stents were removed, fixed with glutaraldehyde for 2 hours, and platelet activation was observed using a scanning electron microscope.

[0082] ④ Cell experiments: The extracts of each scaffold material (prepared according to ISO 10993-12 standard) were co-cultured with cells.

[0083] ⑤ Anti-inflammatory effect: THP-1 macrophages were stimulated with PMA (100 nM) and LPS (100 ng / mL), and the concentrations of TNF-α and iNOS in the culture supernatant were detected by ELISA kit.

[0084] ⑥ Cell proliferation / toxicity: The cell viability of HUVECs and HASMCs after culturing in different extracts for 1 and 3 days was detected by CCK-8 assay.

[0085] ⑦ Migration ability: The scratch test was used to evaluate the migration ability of HUVSMC.

[0086] Conclusion: Various coatings were found to have no significant cytotoxicity to normal endothelial cells and smooth muscle cells, while the EP-C9# coating significantly reduced platelet aggregation, inhibited the release of inflammatory factors, and suppressed smooth muscle migration.

[0087] like Figure 3As shown, endothelial cell compatibility (cell seeding density of 10,000 cells / mL) was assessed using the CCK-8 cytotoxicity assay kit. After culturing cells at the same density on different sample surfaces for 1 and 3 days, the endothelial cell growth status of the sample group was consistent with that of the other groups. This indicates that the assembled peptide coating does not affect endothelial cell proliferation under normal conditions and has no significant cytotoxicity.

[0088] like Figure 4 As shown, the smooth muscle cell compatibility was investigated using the CCK-8 cytotoxicity kit. The results showed that after culturing cells at the same density on different sample surfaces for 1 and 3 days, there was no statistically significant difference in cell count between the sample groups, indicating that the assembled peptide coating had no obvious cytotoxicity.

[0089] like Figure 5 As shown, red arrows indicate activated platelets, while black arrows indicate inactive platelets. High-magnification scanning electron microscopy results show that multilayer assembly of the EP-C9# group coating significantly reduced platelet adhesion, aggregation, and activation.

[0090] like Figure 6 As shown, the supernatant of THP-1 cells in each group was detected by ELISA. The results showed that the EP-C9# coating had the effect of inhibiting the release of pro-inflammatory factors.

[0091] 3. Semi-in vivo and in vivo evaluation of EP-C9-TA coated stent

[0092] Experimental objective: To verify the anticoagulant function and restenosis prevention effect of the stent in semi-in vivo models and animal in vivo models that more closely resemble the physiological environment.

[0093] Experimental conditions and methods: Animals: New Zealand white rabbits, male, weighing 2.5-3.0 kg.

[0094] In vivo evaluation (carotid-jugular shunt model): After anesthesia, the right carotid artery and external jugular vein were isolated. Silicone tubes connected to each group of stents (n=6) were inserted at both ends into the proximal end of the artery and the distal end of the vein, respectively, to establish an external shunt. Blood flow continued through the stents for 1 hour. After completion, the stents were removed, and the surface thrombus and cell adhesion were observed using scanning electron microscopy. The weight of the thrombus was also measured.

[0095] In vivo evaluation (carotid artery stent implantation model): Animals were divided into a commercial control group (rapamycin-eluting stent, DES, Abbott) and an experimental group (the EP-C9-TA coated stent of this invention). A hyperlipidemia model was established by feeding animals a high-fat diet (1% cholesterol) for 4 weeks. Stents (n=8) were implanted into the carotid artery after balloon injury via a femoral artery approach. Vascular specimens were collected 28 days post-implantation for the following analysis:

[0096] ① Histomorphometry: Hematoxylin-eosin (H&E) staining was used to measure the neointimal area (NIA) and luminal area (LA), and the restenosis rate (%stenosis = NIA / (NIA+LA)*100%) was calculated.

[0097] ② Histological analysis: Masson staining was used to evaluate the collagen content of the endometrium; CD31 immunohistochemical staining was used to evaluate the endothelial coverage; α-SMA immunohistochemical staining was used to evaluate smooth muscle cell proliferation.

[0098] Conclusion: Semi-in vivo experiments confirmed that the EP-C9# group of efficiently assembled coated scaffolds can reduce platelet adhesion and leukocyte adhesion. In vivo experiments confirmed that the EP-C9-TA coated scaffold can promote endothelialization and reduce intimal restenosis.

[0099] like Figure 7 As shown, the left figure is a schematic diagram of the in vivo experiment, and the right figure is a sample of the stent after 1 hour of circulation. It can be seen from the figure that EP-C9# can significantly reduce thrombus deposition.

Claims

1. A scaffold based on a fully drug-based structural-functional integrated composite coating, comprising a scaffold body, characterized in that, The outer surface of the stent body is coated with tannic acid coating and EP-C9 peptide coating from the inside out. The tannic acid coating and EP-C9 peptide coating are alternately arranged. One layer of tannic acid coating and one layer of EP-C9 peptide coating are marked as a group. A total of N groups are arranged, where N≥1.

2. The scaffold based on a fully drug-based structural-functional integrated composite coating as described in claim 1, characterized in that, N＝2-4。 3. The scaffold based on a fully drug-based structural-functional integrated composite coating as described in claim 1, characterized in that, The support body is a cobalt-chromium alloy support.

4. The method for preparing the scaffold based on a fully drug-based structural-functional integrated composite coating according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Constructing a tannic acid base coating: The clean scaffold body is subjected to hydrophilic modification treatment, and then the scaffold body is immersed in a tannic acid solution to construct a tannic acid base coating on the surface of the scaffold body. (2) Construction of peptide coating: The scaffold body for constructing tannic acid base coating was immersed in EP-C9 mixed peptide solution, and EP-C9 composite peptide coating was constructed on its surface. (3) Repeated coating construction: Repeat the operations in steps (1) and (2) to construct multiple sets of coatings on the surface of the support body; (4) Curing: Finally, the stent body is dried, cured, and sterilized.

5. The method for preparing the scaffold based on a fully drug-based structural-functional integrated composite coating as described in claim 4, characterized in that, The specific method for hydrophilic modification treatment in step (1) is as follows: place the support body in an oxygen plasma cleaner with a power of 100W and an oxygen flow rate of 20sccm for 10-20 minutes.

6. The method for preparing the scaffold based on a fully drug-based structural-functional integrated composite coating as described in claim 4, characterized in that, In step (1), the concentration of tannic acid solution is 1-2 mg / ml, the pH value of the solution is 5.5-6.0, the immersion temperature is 36-38℃, and the immersion time is 30-45 min.

7. The method for preparing the scaffold based on a fully drug-based structural-functional integrated composite coating as described in claim 4, characterized in that, In step (2), the molar ratio of EP to C9 in the EP-C9 mixed peptide solution is 1:1, the total peptide concentration is 0.5-1 mg / ml, the solution pH is 7.2-7.4, the immersion temperature is 24-26℃, and the immersion time is 30-45 min.

8. The method for preparing the scaffold based on a fully drug-based structural-functional integrated composite coating as described in claim 4, characterized in that, When transferring the stent body from one solution to another, rinse the stent body 2-4 times, each time for 1-2 minutes.

9. The method for preparing the scaffold based on a fully drug-based structural-functional integrated composite coating as described in claim 4, characterized in that, In step (4), the product is dried for 12 hours in a sterile, room temperature environment.

10. The application of the stent based on the all-drug-based structural-functional integrated composite coating according to any one of claims 1-3 in the preparation of cerebral vascular stenosis materials.

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