Active oxygen responsive hydrogel coating for resisting vascular restenosis as well as preparation method and application of active oxygen responsive hydrogel coating

Abstract

The invention relates to the technical field of biomedical materials, and discloses an active oxygen responsive hydrogel coating for resisting vascular restenosis as well as a preparation method and application thereof, the active oxygen responsive hydrogel coating is a hydrogel coating obtained by crosslinking an active oxygen responsive-scavenging polymer prodrug and dopamine modified oxidized dextran; the hydrogel coating is transferred to the inner wall of a blood vessel along with high-pressure expansion of the balloon, responsively degrades under the stimulation of excessive active oxygen in lesion tissues, releases antioxidant drugs, effectively removes local excessive active oxygen, improves the inflammatory microenvironment and inhibits restenosis of the blood vessel.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical materials, and in particular to an active oxygen responsive hydrogel coating for resisting vascular restenosis, and a preparation method and application thereof. Background Art

[0002] Cardiovascular diseases (CVDs) have become the number one killer threatening human health. Percutaneous Coronary Intervention (PCI) has become the mainstream technology for the treatment of cardiovascular diseases due to its characteristics of less trauma, less bleeding, and fewer complications. Drug-Coated Balloons (DCBs), as an innovative "intervention without implantation" treatment solution, have shown significant advantages in preventing in-stent restenosis and inhibiting acute thrombosis. DCBs can efficiently transfer anti-proliferative drugs to the vascular wall while dilating narrowed blood vessels, and will not leave permanent implants, thereby effectively inhibiting local smooth muscle cell proliferation and migration, and delaying the occurrence of postoperative restenosis. Compared with traditional stent implants, DCBs have multiple clinical advantages, including no foreign body residue in the body, no risk of in-stent thrombosis, shortened dual antiplatelet therapy time, reduced bleeding risk, and a wider range of applications. Therefore, DCBs are considered to be a key competitive technology in the field of medical devices with huge market potential.

[0003] However, the coating drugs of existing DCBs mainly include paclitaxel and rapamycin. For example, CN101496813A discloses a composition for treating vascular restenosis or other tissue hyperplasia and its application method. The composition includes rapamycin (Rapamycine), paclitaxel (Paclitaxol) and heparin (Heparin). The application of the composition includes not only systemic administration, but also local slow release of drugs into the diseased tissue. The composition can be applied to the stent or platform by premixing and / or multi-layer spraying. It is confirmed for the first time that the mixture of rapamycin + paclitaxel and the mixture of rapamycin + paclitaxel + heparin have a more significant inhibitory effect on vascular endothelial hyperplasia after stent implantation than any single drug.

[0004] However, these two drugs still face significant limitations in clinical application. Although paclitaxel has a good anti-proliferative effect, it has high systemic toxicity and easy shedding of coating particles; rapamycin has low lipophilicity and slow tissue absorption. These problems greatly limit the clinical pharmacological application and biological effects of this type of drug, and ultimately lead to the occurrence of vascular restenosis. At present, new coating drugs are urgently needed to promote the clinical application of DCBs.

[0005] During vascular interventional therapy, the vascular intima is inevitably torn, triggering inflammatory responses and excessive healing, leading to negative vascular remodeling, smooth muscle cell proliferation and migration, and excessive neointimal hyperplasia. Oxidative stress and inflammatory responses are key early factors in this pathological process, and these responses are closely related to the excessive generation of reactive oxygen species (ROS) in the local microenvironment. Excessive reactive oxygen species not only induce cell apoptosis and tissue damage, but also inhibit the repair of vascular damage. Therefore, timely and effective regulation of the level of reactive oxygen in the traumatic microenvironment and keeping it within the normal range is crucial to promote neointimal regeneration and vascular repair.

[0006] Excessive production of reactive oxygen species provides a precise drug delivery target for the treatment of inflammatory diseases. Reactive oxygen-responsive and scavenging coating materials can not only achieve targeted delivery and controlled release of drugs, but also inhibit inflammation and promote rapid repair of damaged endothelial cells by scavenging reactive oxygen species. Boronate bonds have been widely used in targeted and relieving inflammation due to their responsiveness and consumption of reactive oxygen species. Catechol compounds have also been widely used in antioxidant, anti-inflammatory and anti-infective fields in recent years due to their functional groups such as catechol and acrylic acid. Although these studies provide a theoretical basis for the development of new reactive oxygen-responsive materials, there is currently no reactive oxygen-responsive hydrogel coating constructed in situ based on borate esters and catechol compounds for the inhibition of vascular restenosis.

[0007] Therefore, the development of hydrogel coatings with reactive oxygen species response-scavenging capabilities can provide a potential solution to the clinical problem of vascular restenosis. Summary of the invention

[0008] The present invention aims at the clinical problem of vascular restenosis and provides an active oxygen responsive hydrogel coating for preventing vascular restenosis. The hydrogel coating is transferred to the inner wall of the blood vessel as the balloon is expanded at high pressure, and responsively degrades under the stimulation of excessive active oxygen in the diseased tissue, releasing antioxidant drugs, effectively removing local excess active oxygen, and improving the inflammatory microenvironment, thereby inhibiting vascular restenosis.

[0009] To achieve the above object, the technical solution adopted by the present invention is: An active oxygen responsive hydrogel coating for preventing vascular restenosis, wherein the active oxygen responsive hydrogel coating is a hydrogel coating obtained by cross-linking an active oxygen responsive-scavenging polymer prodrug and dopamine-modified oxidized dextran; The structural formula I of the active oxygen responsive-scavenging polymer prodrug is as follows: (I) Where R1 is H, , , , , , , , , Any one of: R2 is a polycation; The polycation includes one or more of poly-L-lysine, polyethyleneimine, polyaminoamine, polyaminocoester, polyacrylamine, polyquaternary ammonium salt polymer, and polymethacrylate; The structural formula II of the dopamine-modified oxidized dextran is as follows: (II) Where n is a natural number between 50 and 500.

[0010] The active oxygen response-scavenging polymer prodrug in the present invention is a polycation grafted with carboxylphenyl boronate of a catechol compound, and the dopamine-modified oxidized dextran contains an imine bond, and a hydrogel coating is formed by cross-linking the two by a Schiff base reaction, wherein the imine bond and the boronate bond have good active oxygen responsiveness, and break under the triggering of high active oxygen in inflammatory tissues, and can release phenol drugs, remove local excess active oxygen and exert anti-inflammatory and antioxidant functions. At the same time, dopamine modification can enhance the transfer and adhesion of the coating to the inner wall of the blood vessel, improve the delivery efficiency of the drug and prolong its residence time. The hydrogel coating is biodegradable, has good biocompatibility, can alleviate high oxidative stress and inflammatory response, promote rapid repair of the vascular endothelium, and thus effectively inhibit restenosis of blood vessels after intervention.

[0011] The reaction equation for the degradation of the active oxygen responsive-scavenging polymer prodrug is as follows:

[0012] The mass ratio of the active oxygen responsive-scavenging polymer prodrug to the dopamine-modified oxidized dextran is 1:1-1:6, preferably 1:2. At this ratio, the gelling property of the hydrogel is better.

[0013] The preparation of the active oxygen responsive hydrogel coating includes the steps of spraying the active oxygen responsive-scavenging polymer prodrug and dopamine-modified oxidized dextran on the surface of the substrate by ultrasonic atomization, and obtaining the active oxygen responsive hydrogel coating by self-crosslinking. The hydrogel coating is prepared by ultrasonic atomization spraying technology, which has a simple process and mild conditions, and can make the functional components evenly and efficiently coated on the surface of cardiovascular implant interventional devices.

[0014] The preparation process of the active oxygen responsive-scavenging polymer prodrug comprises the steps of: Step 1, reacting a catechol compound as shown in formula M1 and 4-carboxyphenylboronic acid in an anhydrous solvent to obtain catechol carboxyphenylboronic acid ester as shown in formula M2;

[0015] Step 2, dissolving the catechol carboxyl phenyl borate ester represented by formula M2 in a mixed solvent of an organic solvent and water, adding EDC and NHS to mix, then adding a polycation aqueous solution to react, adjusting with an inorganic base and dialyzing to obtain the active oxygen response-scavenging polymer prodrug. The reaction formula is as follows:

[0016] In step 1, the molar ratio of M1 to 4-carboxyphenylboronic acid is 0.5:1-0.9:1, preferably 0.9:1; In step 1, the solvent includes any one or more of N,N-dimethylformamide, dimethyl sulfoxide, dichloromethane, chloroform, toluene or dioxane; In step 1, the reaction temperature is 60-120°C and the reaction time is 4-24h; Preferably, after the solvent is removed from the product of step 1 by rotary evaporation, the product is dissolved in ethyl acetate and the product is purified by recrystallization.

[0017] In step 2, the molar ratio of M2 to polycation is 100:1-10:1, preferably 80:1; The organic solvent in step 2 includes any one or more of dimethyl sulfoxide, dichloromethane, chloroform, methanol, ethanol, N,N-dimethylformamide, and tetrahydrofuran.

[0018] The molar ratio of EDC to NHS is 1:1-1.2:1, preferably 1.2:1; the molar ratio of EDC to M2 is 1.1:1-1.5:1; The volume ratio of the organic solvent to water in the mixed solvent is 2:1-8:1, preferably 4:1, so that the feed solubility is good and the reaction is more complete.

[0019] The polycation includes one or more of poly-L-lysine, polyethyleneimine, polymethacrylate, and polyamino dendrimer, preferably polyethyleneimine; the polycation provides abundant amino groups, which can be used as a macromolecular skeleton to graft M2 to achieve antioxidant effect; on the other hand, the hydrogel coating is formed by the Schiff base reaction between the amino group and the aldehyde group of oxidized dextran.

[0020] The catechol compound represented by formula M1 includes one or more of caffeic acid, hydroxytyrosol, norepinephrine, epinephrine, quercetin, catechin, and proanthocyanidin.

[0021] In step 2, the reaction temperature is room temperature and the reaction time is 12-24h; The pH of the polycation aqueous solution is 5.0-6.0; after the reaction is completed, the inorganic base is used to adjust the pH to 7.0-7.2.

[0022] The preparation process of the dopamine-modified oxidized dextran comprises the steps of: oxidizing dextran with sodium periodate to obtain oxidized dextran, adding dopamine hydrochloride to an aqueous solution of oxidized dextran for reaction, dialyzing and freeze-drying to obtain the dopamine-modified oxidized dextran.

[0023] The molecular weight of the dextran is 10k-100kDa, preferably 40kDa; the molecular weight affects the viscosity. If the viscosity is too high, it is difficult to spray and difficult to prepare.

[0024] The molar ratio of the number of polymerization units of the dextran to sodium periodate is 10:1-1:2, preferably 2:1; the temperature of the oxidation reaction is room temperature, and the reaction time is 4-24 hours; The molar ratio of the number of polymerization units of the dextran to dopamine hydrochloride is 10:1-2:1, preferably 3:1; The reaction temperature of dopamine hydrochloride and oxidized dextran is room temperature, and the reaction time is 6-24 hours.

[0025] The present invention also provides a method for preparing the active oxygen responsive hydrogel coating for preventing vascular restenosis, comprising the steps of: spraying an aqueous solution of active oxygen responsive-scavenging polymer prodrugs and an aqueous solution of dopamine-modified oxidized dextran on the surface of a substrate by ultrasonic atomization, respectively, and obtaining the active oxygen responsive hydrogel coating by self-crosslinking.

[0026] Through ultrasonic atomization spraying technology, active oxygen response-scavenging polymer prodrug and dopamine-modified oxidized dextran undergo Schiff base reaction on the substrate surface to obtain a hydrogel cross-linked network. The preparation method is simple in process and mild in conditions, and can evenly and efficiently coat the functional components on the surface of cardiovascular implants.

[0027] The mass fraction of the active oxygen responsive-scavenging polymer prodrug aqueous solution is 0.1 wt%-10 wt%, preferably 2 wt%; The mass fraction of the dopamine-modified oxidized dextran aqueous solution is 0.4 wt%-40 wt%, preferably 4 wt%; if the dextran is too high, the viscosity is large and the spraying is not smooth; if the content is too low, the Schiff base reaction is weak and it is not easy to cross-link into a film. At the same time, the loading amount is low and the expected effect is poor.

[0028] The mass ratio of the active oxygen responsive-scavenging polymer prodrug to dopamine-modified oxidized dextran is 1:1-1:6, preferably 1:2; The ultrasonic atomization spraying rate is 2-20 μL per minute, preferably 10 μL per minute; the thickness of the hydrogel coating is 2-20 μm, preferably 5-10 μm; the spraying speed affects the coating morphology and cross-linking structure; the coating thickness corresponds to the drug loading, the thicker the coating, the better the anti-restenosis effect.

[0029] The substrate includes one or more of polyethylene terephthalate, polydimethylsiloxane, polyurethane, high-density polyethylene, polyamide, polytetrafluoroethylene, polyvinyl chloride, acrylate, etc., preferably polyethylene terephthalate.

[0030] The present invention also provides application of the active oxygen responsive hydrogel coating for resisting vascular restenosis in preparing medical materials for resisting vascular restenosis.

[0031] The hydrogel coating of the present invention degrades under the stimulation of active oxygen at the site of vascular lesions, releasing phenolic compounds, eliminating local excess active oxygen, improving the inflammatory microenvironment, promoting endothelial repair and delaying the process of restenosis of blood vessels. The coating is biodegradable and can achieve controlled long-term release of drugs, thereby improving the bioavailability of drugs.

[0032] For example, when preparing a balloon material, a coating is applied to the surface of the balloon; the balloon catheter material includes one or more of polyvinyl chloride, polyethylene, polyurethane, polyethylene terephthalate, nylon, and polyether block amide, preferably polyether block amide; the inner diameter of the balloon catheter is 1.0-5.0 mm, preferably 1.25-1.5 mm; the length of the balloon catheter is 10-30 mm, preferably 15-25 mm.

[0033] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention applies the reactive oxygen species responsive hydrogel platform to the design of vascular balloon coatings, achieving controllable, on-demand and long-acting drug release, effectively reducing or avoiding drug toxic side effects, and significantly improving drug bioavailability, thereby expected to achieve better therapeutic effects.

[0034] (2) The present invention forms a hydrogel cross-linked network by chemically cross-linking polymer prodrugs and modified dextran. The prepared hydrogel coating can quickly respond to degradation under high expression levels of reactive oxygen species, release antioxidant drugs, eliminate excessive reactive oxygen species, and thus improve the local inflammatory microenvironment and delay the process of vascular restenosis. At the same time, the introduction of dopamine enhances the transfer and adhesion ability of the coating on the inner wall of the blood vessel, further improving the delivery efficiency of the drug and prolonging its retention time.

[0035] (3) The hydrogel coating of the present invention can gel in situ, and the chemical cross-linking is relatively strong, which reduces the possible loss of drugs during balloon delivery. By adjusting the functional components and proportions, the drug loading, mechanical properties and drug release rate of the coating can be accurately controlled. In addition, the ultrasonic atomization spraying process is adopted, which is easy to operate, highly repeatable and controllable, ensuring the uniformity and consistency of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the active oxygen responsive-scavenging polymer prodrug PEI-CBEC prepared in Example 1.

[0037] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of the dopamine-modified oxidized dextran OD-PDA prepared in Example 1.

[0038] Figure 3 This is the appearance of the active oxygen responsive hydrogel with different mass ratios of PEI-CBEC and OD-PDA prepared in Example 1.

[0039] Figure 4 This is the active oxygen responsive degradation curve of the active oxygen responsive hydrogel coating prepared in Example 1.

[0040] Figure 5 This is the active oxygen scavenging ability curve of the active oxygen responsive hydrogel coating prepared in Example 2.

[0041] Figure 6 This is the active oxygen inhibition status of cells on the surface of the active oxygen responsive hydrogel coating prepared in Example 3.

[0042] Figure 7 FIG. 7 a is an apparent image of the active oxygen responsive hydrogel coating prepared in Example 4, and FIG. 7 b is a microscopic image of the active oxygen responsive hydrogel coating prepared in Example 4.

[0043] Figure 8 The transfer of the active oxygen responsive hydrogel coating prepared in Example 4 to the inner wall of the rat carotid artery.

[0044] Fig. 9 This is the inhibitory effect of the active oxygen responsive hydrogel coating prepared in Example 5 on the active oxygen in the intervention site of the rat abdominal aorta. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiment. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Those skilled in the art can make modifications or equivalent substitutions based on the understanding of the technical scheme of the present invention without departing from the spirit and scope of the technical scheme of the present invention, and all should be included in the protection scope of the present invention.

[0046] The raw materials used in the following specific embodiments are all purchased from the market.

[0047] Example 1 (I) Preparation of reactive oxygen species responsive-scavenging polymer prodrugs: Step 1-1, dissolve caffeic acid ethyl ester (EC) (1.87 g, 9 mmol) and 4-carboxyphenylboronic acid (CBA) (1.38 g, 10 mmol) in 10 mL N,N-dimethylformamide (DMF), stir at 100°C for 8 hours, and the solution gradually turns into clear dark green. After the reaction is completed, remove the solvent by rotary evaporation, add 5 mL of pre-cooled ethyl acetate to dissolve the concentrate, and recrystallize at -20°C overnight. Collect the precipitated white solid and dry it in vacuum to obtain the intermediate product 4-carboxyphenylboronic acid caffeic acid ethyl ester (CBEC);

[0048] Step 1-2, adjust the pH of the aqueous solution of polyethyleneimine (PEI) (1.0 g, 0.04 mmol) to 5.0. Then, the CBEC (1.196 g, 3.20 mmol) prepared in step 1-1 was dissolved in a mixture of dimethyl sulfoxide (8 mL) and water (2 mL) and stirred at room temperature for 30 minutes to release heat. EDC (0.669 g, 3.49 mmol) and NHS (0.368 g, 3.20 mmol) were then added to the mixture, and after stirring for 2 hours, the mixture was added to the PEI solution. After reacting for 24 hours, the mixture was dialyzed and freeze-dried to finally obtain polyethyleneimine modified with 4-carboxyphenylboronic acid caffeic acid ethyl ester (PEI-CBEC), the structural formula of which is as follows:

[0049]

[0050] Figure 1 This is the H-NMR spectrum of PEI-CBEC. Its successful synthesis can be seen from its peak position.

[0051] (II) Preparation of dopamine-modified oxidized dextran: Step 2-1, at room temperature, slowly dropwise add sodium periodate (6.34 g, 29.6 mmol) aqueous solution to dextran (10.0 g, 61.7 mmol, molecular weight 40 kDa) aqueous solution, stir and react for 6 hours, add 20 mL ethylene glycol and continue stirring for 2 hours to neutralize the unreacted sodium periodate, dialyze and freeze-dry to obtain oxidized dextran (OD); Step 2-2, dissolve the OD (5.6 g, 34.6 mmol) obtained in step 2-1 in 100 mL of pH 7.4 distilled water, then add dopamine hydrochloride (2.1 g, 11.1 mmol), and stir at room temperature for 12 hours. After the reaction, dialyze and freeze-dry to obtain dopamine-modified oxidized dextran (OD-PDA), the structural formula of which is as follows, n is 200:

[0052] Figure 2 This is the H NMR spectrum of the OD-PDA prepared above. Its peak position indicates that it was successfully synthesized.

[0053] 3. Exploration of the ratio between PEI-CBEC and OD-PDA hydrogels PEI-CBEC and OD-PDA were dissolved in distilled water (PEI-CBEC mass concentration was 2 wt%, OD-PDA mass concentration was 4 wt%), and mixed quickly according to different mass ratios (2:1, 1:4, 1:2, 1:1), and allowed to stand for 10 min. Then, the gel was inverted to observe the gel flow.

[0054] Figure 3 This is a photo of PEI-CBEC@OD-PDA gel. The experimental results show that the hydrogel formed by cross-linking PEI-CBEC / OD-PDA at a mass ratio of 1:2 is more uniform and stable.

[0055] (IV) Preparation of reactive oxygen species responsive hydrogel coating: PEI-CBEC and OD-PDA were dissolved in distilled water (the mass concentration of PEI-CBEC was 2 wt% and the mass concentration of OD-PDA was 4 wt%), respectively, with a mass ratio of PEI-CBEC to OD-PDA of 1:2. They were evenly coated on the pre-cleaned, sterilized, and expanded polyethylene terephthalate (PET) surface using a double-head ultrasonic atomization spraying technique (the spraying rate was set to 10 μL per minute and the spraying thickness was 5 μm), and quickly cross-linked to form a hydrogel coating PEI-CBEC@OD-PDA.

[0056] The prepared coatings were immersed in PBS buffer (pH 7.4, 0.1 M) containing 1 mM and 10 mM H2O2, respectively, and incubated at 37°C and 50 rpm / min with shaking. PBS without H2O2 was used as a negative control. 100 μL of samples were taken at different time points (0 min, 10 min, 20 min, 40 min, 60 min, 120 min) and supplemented with the same amount of PBS. The absorbance at 280 nm was detected by an ELISA instrument, and the release of degradation products was quantified according to the standard curve to calculate the cumulative release rate of the drug.

[0057] Figure 4 The ROS-responsive degradation and drug release experiments of PEI-CBEC@OD-PDA coating in the absence or presence of hydrogen peroxide (H2O2) were performed. The experimental results show that the coating can be rapidly degraded and release phenolic compounds under high levels of reactive oxygen species (1 mM and 10 mM H2O2) in simulated inflammatory tissue. And with the increase of H2O2 concentration, the drug release rate and cumulative release amount increased significantly, indicating that the coating has significant responsiveness to high ROS.

[0058] Example 2 The preparation process of active oxygen responsive-scavenging polymer prodrug and dopamine-modified oxidized dextran is as in Example 1. Preparation of active oxygen responsive hydrogel coating: PEI-CBEC and OD-PDA were dissolved in distilled water, the mass concentration of PEI-CBEC was 4 wt%, the mass concentration of OD-PDA was 8 wt%, and the mass ratio of PEI-CBEC to OD-PDA was 1:2. Double-head ultrasonic atomization spraying technology (spraying rate was set to 20 μL per minute, spraying thickness was 10 μm) was used to evenly coat the pre-cleaned and sterilized PET surface, and quickly cross-linked to form a hydrogel coating.

[0059] The area is 0.25 mm 2 , 0.5 mm 2 , 1.0 mm 2 , 2.0 mm 2 , 3.0 mm 2 The coating material was placed in a 2,2-biphenyl-1-picrylhydrazyl (DPPH) ethanol solution with a final concentration of 0.1 mM and incubated at 37°C in the dark for 30 minutes. The absorbance at 517 nm was measured using an ELISA reader and compared with the sample solution (A 样品 ) and pure DPPH ethanol solution (A 对照 ) absorbance. The calculation formula for DPPH free radical scavenging rate is:

[0060] .

[0061] Figure 5 The hydrogel coating was demonstrated to have a significant free radical scavenging ability. The results showed that the hydrogel coating had a significant free radical scavenging ability, and the scavenging efficiency increased with the increase of coating area. The more cross-linked the gel, the more stable the coating. Moreover, in the same time, the more sprayed, the higher the scavenging rate in theory.

[0062] Example 3 The preparation process of active oxygen responsive-scavenging polymer prodrug and dopamine-modified oxidized dextran is as in Example 1. Preparation of active oxygen responsive hydrogel coating: PEI-CBEC and OD-PDA were dissolved in distilled water, with a PEI-CBEC concentration of 2 wt%, an OD-PDA concentration of 4 wt%, and a PEI-CBEC to OD-PDA mass ratio of 1:2. Double-head ultrasonic atomization spraying technology (spraying rate set at 10 μL per minute, spraying thickness of 10 μm) was used to coat the pre-cleaned and sterilized PET surface, and rapidly cross-linked to form a hydrogel coating.

[0063] First, human umbilical vein endothelial cells (HUVECs) were stimulated with lipopolysaccharide (LPS) (1 μg / mL) and cultured overnight. 4 Cells / cm 2 HUVECs were seeded on bare PET and PEI-CBEC@OD-PDA coated surfaces, and unstimulated HUVECs were used as the normal control group. After 24 hours of culture, DHE dye (1:1000 dilution in serum-free medium) was used for staining at 37°C for 40 minutes in the dark, and the fluorescence intensity of cells in different groups was observed using a fluorescence microscope. The DHE fluorescence intensity was quantitatively analyzed to evaluate the amount of ROS generated.

[0064] Figure 6 The ROS probe (DHE) was used to evaluate the antioxidant capacity of the coating. The results showed that compared with the inflammatory group, the coating treatment group significantly reduced the generation of intracellular reactive oxygen species and was close to the reactive oxygen expression level of normal cells. The thicker the coating, the better the inhibitory effect on intracellular reactive oxygen species.

[0065] Example 4 The preparation process of active oxygen responsive-scavenging polymer prodrug and dopamine-modified oxidized dextran is as in Example 1. Preparation of active oxygen responsive hydrogel coating: PEI-CBEC and OD-PDA were dissolved in distilled water, the mass concentration of PEI-CBEC was 2 wt%, the mass concentration of OD-PDA was 4 wt%, and the mass ratio of PEI-CBEC to OD-PDA was 1: 2. The double-head ultrasonic atomization spraying technology (the spraying rate was set to 15 μL per minute, and the spraying thickness was 8 μm) was spin-coated on the pre-cleaned, sterilized, and expanded balloon surface (the balloon catheter material was polyether block amide, the catheter inner diameter was 1.25 mm, and the length was 15 mm), and the hydrogel coating was quickly cross-linked to form a hydrogel coating.

[0066] Figure 7 The apparent and microscopic images of the hydrogel coating are presented, indicating that the coating is evenly distributed on the balloon surface and well loaded. Figure 8 The transfer of the coating to the inner wall of the blood vessel was demonstrated. The experiment used a rat common carotid aorta injury model, and a balloon coated with PEI-CBEC@OD-PDA was placed into the aorta through an incision. The balloon was deflated and removed after being expanded at 8 atm pressure for 1 minute. The coating conditions of the artery and balloon before and after intervention were observed using a fluorescence imaging system. The results showed that the coating showed good transfer and adhesion properties during balloon expansion.

[0067] Example 5 The preparation process of active oxygen responsive-scavenging polymer prodrug and dopamine-modified oxidized dextran is as in Example 1. Preparation of active oxygen responsive hydrogel coating: PEI-CBEC and OD-PDA were dissolved in distilled water, the mass concentration of PEI-CBEC was 2 wt%, the mass concentration of OD-PDA was 4 wt%, and the mass ratio of PEI-CBEC to OD-PDA was 1: 2. The hydrogel coating was quickly formed by applying it on the pre-cleaned, sterilized, and expanded balloon surface (the balloon catheter material was polyether block amide, the balloon inner diameter was 1.5 mm, and the catheter length was 15 mm) using double-head ultrasonic atomization spraying technology (the spraying rate was set to 5 μL per minute and the spraying thickness was 3 μm).

[0068] The rat abdominal aorta injury model was used for the experiment, and the stenotic blood vessels were dilated using a balloon coated with PEI-CBEC@OD-PDA. Three days after surgery, the level of ROS in the abdominal aorta in vivo was detected by intraperitoneal injection of L-012 chemical probe. Fig. 9 The effect of the hydrogel coating on the level of postoperative reactive oxygen species was demonstrated. The experimental results showed that compared with the untreated injury group, the coating group effectively reduced the expression of postoperative reactive oxygen species and was close to the reactive oxygen levels of normal rats.

Claims

1. An active oxygen responsive hydrogel coating for preventing vascular restenosis, characterized in that: The active oxygen responsive hydrogel coating is a hydrogel coating obtained by cross-linking an active oxygen responsive-scavenging polymer prodrug and dopamine-modified oxidized dextran; The structural formula I of the active oxygen responsive-scavenging polymer prodrug is as follows: （I）； Where R1 is H, , , , , , , , , Any one of: R2 is a polycation; The polycation includes one or more of poly-L-lysine, polyethyleneimine, polyaminoamine, polyaminocoester, polyacrylamine, polyquaternary ammonium salt polymer, and polymethacrylate; The structural formula II of the dopamine-modified oxidized dextran is as follows: (II); Where n is a natural number between 50 and 500.

2. The active oxygen responsive hydrogel coating for preventing vascular restenosis according to claim 1, characterized in that: The mass ratio of the active oxygen responsive-scavenging polymer prodrug to the dopamine-modified oxidized dextran is 1:1-1:

6.

3. The active oxygen responsive hydrogel coating for preventing vascular restenosis according to claim 1, characterized in that: The preparation of the active oxygen responsive hydrogel coating comprises the steps of: spraying active oxygen responsive-scavenging polymer prodrug and dopamine-modified oxidized dextran on the surface of a substrate by ultrasonic atomization, and obtaining the active oxygen responsive hydrogel coating by self-crosslinking.

4. The active oxygen responsive hydrogel coating for preventing vascular restenosis according to claim 1, characterized in that: The preparation process of the active oxygen responsive-scavenging polymer prodrug comprises the steps of: Step 1, reacting a catechol compound as shown in formula M1 and 4-carboxyphenylboronic acid in an anhydrous solvent to obtain catechol carboxyphenylboronic acid ester as shown in formula M2; ； Step 2, dissolving the catechol carboxyl phenyl borate shown in formula M2 in a mixed solvent of an organic solvent and water, adding EDC and NHS to mix, then adding a polycation aqueous solution to react, adjusting with an inorganic base and dialyzing to obtain the active oxygen response-scavenging polymer prodrug.

5. The active oxygen responsive hydrogel coating for preventing vascular restenosis according to claim 4, characterized in that: In step 1, the molar ratio of M1 to 4-carboxyphenylboronic acid is 0.5:1-0.9:1; In step 1, the solvent includes any one or more of N,N-dimethylformamide, dimethyl sulfoxide, dichloromethane, chloroform, toluene or dioxane; In step 1, the reaction temperature is 60-120°C and the reaction time is 4-24h; In step 2, the molar ratio of M2 to polycation is 100:1-10:1; In step 2, the organic solvent includes any one or more of dimethyl sulfoxide, dichloromethane, chloroform, methanol, ethanol, N,N-dimethylformamide, and tetrahydrofuran; The molar ratio of EDC to NHS is 1:1-1.2:1; the molar ratio of EDC to M2 is 1.1:1-1.5:1; The volume ratio of the organic solvent to water in the mixed solvent is 2:1-8:1; The polycation includes one or more of poly-L-lysine, polyethyleneimine, polymethacrylate, and polyamino dendrimer; In step 2, the reaction temperature is room temperature and the reaction time is 12-24h; The pH of the polycation aqueous solution is 5.0-6.0; after the reaction is completed, the inorganic base is used to adjust the pH to 7.0-7.

2.

6. The active oxygen responsive hydrogel coating for preventing vascular restenosis according to claim 1, characterized in that: The preparation process of the dopamine-modified oxidized dextran comprises the steps of: oxidizing dextran with sodium periodate to obtain oxidized dextran, adding dopamine hydrochloride to an aqueous solution of oxidized dextran for reaction, dialyzing and freeze-drying to obtain the dopamine-modified oxidized dextran.

7. The active oxygen responsive hydrogel coating for preventing vascular restenosis according to claim 6, characterized in that: The molecular weight of the dextran is 10k-100kDa; The molar ratio of the number of polymerization units of the dextran to sodium periodate is 10:1-1:2; the temperature of the oxidation reaction is room temperature, and the reaction time is 4-24 hours; The molar ratio of the number of polymerization units of the dextran to dopamine hydrochloride is 10:1-2:1; The reaction temperature of dopamine hydrochloride and oxidized dextran is room temperature, and the reaction time is 6-24h.

8. The method for preparing the active oxygen responsive hydrogel coating for preventing vascular restenosis according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: spraying an aqueous solution of active oxygen responsive-scavenging polymer prodrugs and an aqueous solution of dopamine-modified oxidized dextran on the surface of a substrate respectively by ultrasonic atomization, and obtaining the active oxygen responsive hydrogel coating by self-crosslinking.

9. The method for preparing the active oxygen responsive hydrogel coating for preventing vascular restenosis according to claim 8, characterized in that: The mass fraction of the active oxygen responsive-scavenging polymer prodrug aqueous solution is 0.1 wt%-10 wt%; The mass fraction of the dopamine-modified oxidized dextran aqueous solution is 0.4 wt%-40 wt%; The mass ratio of the active oxygen responsive-scavenging polymer prodrug to dopamine-modified oxidized dextran is 1:1-1:6; The ultrasonic atomization spraying rate is 2-20 μL per minute; the thickness of the hydrogel coating is 2-20 μm; The substrate includes one or more of polyethylene terephthalate, polydimethylsiloxane, polyurethane, high-density polyethylene, polyamide, polytetrafluoroethylene, polyvinyl chloride, and acrylate.

10. Use of the active oxygen responsive hydrogel coating for preventing vascular restenosis according to any one of claims 1 to 7 in preparing medical materials for preventing vascular restenosis.

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