WO2022021363A1 - Coating composition, hydrogel coating and preparation method therefor, and coated product - Google Patents

Abstract

The present invention relates to a coating composition, a hydrogel coating and a preparation method therefor, and a coated product. The coating composition comprises the following components in parts by weight: 2-100 parts of polyethylene glycol diacrylate, 0.02-2 parts of a thrombin-responsive crosslinking agent, 0.001-0.2 part of fibrinolytic active molecules, 0.002-1 part of a photosensitizer, and 50-2000 parts of a solvent. After the coating composition is cured, a hydrogel coating is obtained. The system can encapsulate the fibrinolytic active molecules while forming the hydrogel coating by crosslinking, thereby forming a thrombin-responsive hydrogel coating. During a process of thrombin-responsive release of the fibrinolytic active molecules, the hydrogel coating is not completely degraded and can continuously provide the surface with anti-protein adsorption properties. The hydrogel coating not only achieves a thrombotic stress fibrinolysis function, but also can maintain biological inertia in a non-thrombotic environment.

Description

Coating composition, hydrogel coating, method of making the same, and coated article technical field

The present invention relates to the technical field of coatings, in particular to a coating composition, a hydrogel coating, a preparation method thereof, and a coated product.

Background technique

Implantation of blood-contacting materials usually disturbs the balance of procoagulant and anticoagulant factors in the human vascular system, directly or indirectly leading to coagulation and thrombosis, which greatly limits its successful application. The process of foreign body contact thrombosis includes the initial rapid protein adsorption, the subsequent platelet adhesion and activation, and the subsequent cascade reaction of a series of coagulation factors. And these processes are interrelated and inseparable from each other. Based on this, researchers started from blood-compatible surface modification to construct biologically inert surfaces and biologically active surfaces. The former tries to reduce the interaction of the material surface with the blood defense system (mainly inhibiting the adsorption of proteins), while the latter tries to counteract the coagulation activation process or activate the fibrinolysis process.

Bioactive hemocompatible surfaces generally provide more effective hemocompatibility than inert surfaces due to the fact that they provide anticoagulant or fibrinolytic properties directly on the surface of the material. Ideally, implanted biomaterials should respond appropriately to specific changes in the physiological environment as needed. That is, only when the coagulation reaction leads to the formation of fibrin, the fibrinolytic system will be passively accelerated and activated, which can improve the drug use cycle and reduce hemorrhagic complications. However, when using traditional hydrogel coatings, the original hydrogel structure is destroyed with the degradation of thrombin, and once the degradation is complete, the blood-contacting material will revert to the bare unmodified state and trigger subsequent The coagulation process is not conducive to application.

SUMMARY OF THE INVENTION

According to various embodiments of the present application, there are provided a coating composition, a hydrogel coating, a method for making the same, and a coated article that can avoid complete degradation.

According to one aspect of the present application, a coating composition is provided, comprising the following components in parts by mass:

After the above coating composition is cured, a hydrogel coating is obtained, and the system can encapsulate fibrinolytic active molecules while being cross-linked to form the hydrogel coating to form a thrombin-responsive hydrogel coating. Among them, polyethylene glycol diacrylate provides good resistance to non-specific protein adsorption for the hydrogel coating. Since the hydrogel coating contains both non-degradable polyethylene glycol diacrylate and a thrombin-degradable thrombin-responsive cross-linking agent, the hydrogel is free from thrombin-responsive release of fibrinolytic active molecules. The coating will not degrade completely and will continue to provide the surface with resistance to protein adsorption. In this way, the thrombus-stressed fibrinolytic function can be achieved, and the biological inertness can be maintained in a non-thrombotic environment. After the above coating composition is cured, a simple and efficient responsive thrombolytic hydrogel coating can be obtained, which has a good application prospect in the practical fibrinolytic active molecule drug-loading coating.

In one of the embodiments, the following components are included in parts by mass:

In one embodiment, the molecular weight of the polyethylene glycol diacrylate is 100-20,000.

In one embodiment, the fibrinolytic activity molecule is selected from at least one of tissue-type plasminogen activator, urokinase-type plasminogen activator and streptokinase.

In one embodiment, the solvent is protein buffer or water.

According to another aspect of the present application, there is provided a hydrogel coating obtained by curing the above coating composition.

According to another aspect of the present application, there is provided a method for preparing the above-mentioned hydrogel coating, characterized in that it comprises the following steps:

Dissolving polyethylene glycol diacrylate, thrombin-responsive cross-linking agent, fibrinolytic active molecule and photosensitizer in a solvent, and mixing uniformly to obtain a prepolymerized solution;

The prepolymerized solution is coated on the surface of the substrate, and after photocuring, a hydrogel coating is obtained.

According to yet another aspect of the present application, there is provided a coated article comprising a substrate and the above-mentioned hydrogel coating, the hydrogel coating being coated on the surface of the substrate.

The above-mentioned coated product includes the above-mentioned simple and efficient responsive thrombolytic hydrogel coating, which not only realizes the function of thrombus stress-induced fibrinolysis, but also maintains biological inertness in a non-thrombotic environment. It has good application prospects in terms of layers.

In one embodiment, the substrate is a medical device.

In one embodiment, the material of the substrate is polymer, metal or metal oxide.

The details of one or more embodiments of the application are set forth in the accompanying drawings and the description below. Other features, objects and advantages of the present application will become apparent from the description, drawings and claims.

Description of drawings

In order to better describe and illustrate embodiments or examples of those inventions disclosed herein, reference may be made to one or more of the accompanying drawings. The additional details or examples used to describe the drawings should not be construed as limiting the scope of any of the disclosed inventions, the presently described embodiments or examples, and the best mode presently understood of these inventions.

Figure 1(a) is a scanning electron microscope (SEM) image of the hydrogel coating of Comparative Example 1;

Figure 1(b) is a scanning electron microscope (SEM) image of the hydrogel coating of Example 3;

Figure 1(c) is a scanning electron microscope (SEM) image of the hydrogel coating of Example 2;

Figure 1(d) is a scanning electron microscope (SEM) image of the hydrogel coating of Example 1;

Figure 1(e) is a scanning electron microscope (SEM) image of the hydrogel coating of Comparative Example 1 after incubation in thrombin solution for 5 hours;

Figure 1(f) is a scanning electron microscope (SEM) image of the hydrogel coating of Example 3 after being incubated in a thrombin solution for 5 hours;

Figure 1(g) is a scanning electron microscope (SEM) image of the hydrogel coating of Example 2 after being incubated in a thrombin solution for 5 hours;

Figure 1(h) is a scanning electron microscope (SEM) image of the hydrogel coating of Example 1 after incubation in a thrombin solution for 5 hours;

Figure 2(a) is a graph showing the release curves of t-PA in the hydrogel coating of Example 4 in PBS solution and thrombin solution (10 U/mL) respectively;

Figure 2(b) shows the release curves of t-PA in PBS solution and thrombin solution (10 U/mL) in the hydrogel coating of Comparative Example 1;

Fig. 3 is the adsorption diagram of Fg on the surface before and after the degradation of the hydrogel coatings of Example 5 and Comparative Example 1;

4 is a graph showing the results of the dissolution test of the hydrogel coatings of Example 6 and Comparative Example 1 on fibrin clots.

detailed description

In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein in the specification of the application are for the purpose of describing specific embodiments only, and are not intended to limit the application. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, all It is considered to be the range described in this specification.

The coating composition of one embodiment includes the following components in parts by mass:

Among them, polyethylene glycol diacrylate (PEGDA) as the main skeleton component provides good anti-nonspecific protein adsorption performance for the hydrogel coating obtained after curing. Due to the introduction of polyethylene glycol diacrylate, after thrombin degrades the thrombin-responsive cross-linking agent, the remaining polyethylene glycol diacrylate backbone still exists and exerts anti-protein adsorption properties.

The thrombin-responsive cross-linking agent is a polypeptide (Pep) cross-linking agent, and the structure includes a thrombin-cleavable substrate, a polypeptide or an aptamer fragment, and at least two cross-linkable unsaturated bonds.

Among them, the fibrinolytic active molecule is used as a functional drug molecule, and as a loaded drug, the system can be cross-linked under the condition of ultraviolet light to form a hydrogel coating and can encapsulate the fibrinolytic active molecule to form a thrombin-responsive hydrogel coating .

Among them, photosensitizer, also known as photoinitiator, is used to absorb energy of a certain wavelength in the ultraviolet region (250nm-420nm) or visible light region (400nm-800nm) to generate free radicals, cations, etc., thereby initiating monomer polymerization and crosslinking curing .

Among them, the solvent is used for dissolving polyethylene glycol diacrylate, thrombin-responsive cross-linking agent, fibrinolytic active molecule and photosensitizer.

After the above coating composition is cured, a hydrogel coating is obtained, and the system can encapsulate fibrinolytic active molecules while being cross-linked to form a hydrogel coating to form a thrombin-responsive hydrogel coating. Since the hydrogel coating contains both non-degradable polyethylene glycol diacrylate and a thrombin-degradable thrombin-responsive cross-linking agent, the hydrogel is free from thrombin-responsive release of fibrinolytic active molecules. The coating will not degrade completely and will continue to provide the surface with resistance to protein adsorption.

In one embodiment, the coating composition includes the following components in parts by mass:

In one embodiment, the molecular weight of polyethylene glycol diacrylate is 100-20,000. Preferably, the molecular weight of polyethylene glycol diacrylate is 200-10,000.

In one embodiment, the structure of the thrombin-responsive cross-linking agent comprises a thrombin-cleavable substrate, polypeptide or aptamer fragment, and at least two cross-linkable unsaturated bonds.

In one embodiment, the fibrinolytic activity molecule is selected from tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA) and streptokinase (SK) at least one of.

In one embodiment, the solvent is protein buffer or water. When the solvent is a protein buffer, the pH range of the protein buffer is 6-10, preferably 7-9.

In one embodiment, the photosensitizer is selected from at least one of a hydrogen abstraction type photoinitiator (eg, benzophenone) and a cleavage type photoinitiator (eg, photoinitiator 2959).

After the above coating composition is cured, a hydrogel coating is obtained, and the system can encapsulate fibrinolytic active molecules while being cross-linked to form the hydrogel coating to form a thrombin-responsive hydrogel coating. Among them, polyethylene glycol diacrylate provides good resistance to non-specific protein adsorption for the hydrogel coating. Since the hydrogel coating contains both non-degradable polyethylene glycol diacrylate and a thrombin-degradable thrombin-responsive cross-linking agent, the hydrogel is free from thrombin-responsive release of fibrinolytic active molecules. The coating will not degrade completely and will continue to provide the surface with resistance to protein adsorption. In this way, the thrombus-stressed fibrinolytic function can be achieved, and the biological inertness can be maintained in a non-thrombotic environment. After the above coating composition is cured, a simple and efficient responsive thrombolytic hydrogel coating can be obtained, which has a good application prospect in the practical fibrinolytic active molecule drug-loading coating.

The hydrogel coating of one embodiment is obtained by curing the above-mentioned coating composition.

In the above hydrogel coating, the system can encapsulate fibrinolytic active molecules while forming the hydrogel coating by cross-linking to form a hydrogel coating with thrombin responsiveness. Among them, polyethylene glycol diacrylate provides good resistance to non-specific protein adsorption for the hydrogel coating. Since the hydrogel coating contains both non-degradable polyethylene glycol diacrylate and a thrombin-degradable thrombin-responsive cross-linking agent, the hydrogel is free from thrombin-responsive release of fibrinolytic active molecules. The coating will not degrade completely and will continue to provide the surface with resistance to protein adsorption. In this way, the thrombus-stressed fibrinolytic function can be achieved, and the biological inertness can be maintained in a non-thrombotic environment. The above-mentioned responsive thrombolytic hydrogel coating is simple and efficient, and has a good application prospect in the actual fibrinolytic active molecule drug-loading coating.

The preparation method of the above-mentioned hydrogel coating of one embodiment, comprises the steps:

S10, dissolving polyethylene glycol diacrylate, a thrombin-responsive cross-linking agent, a fibrinolytic active molecule and a photosensitizer in a solvent, and mixing uniformly to obtain a prepolymerized solution.

The above-mentioned raw materials can be mixed uniformly by stirring, and the obtained prepolymerization solution is a transparent solution.

In one embodiment, the mass ratio of polyethylene glycol diacrylate, thrombin-responsive cross-linking agent, fibrinolytic active molecule, photosensitizer and solvent is 2-100: 0.02-2: 0.001-0.2: 0.002-1 : 50～2000.

Further, the mass ratio of polyethylene glycol diacrylate, thrombin-responsive cross-linking agent, fibrinolytic active molecule, photosensitizer and solvent is 3-60:0.05-1:0.002-0.06:0.01-0.5:100-1000 .

Further, the molecular weight of polyethylene glycol diacrylate is 100-20,000. Preferably, the molecular weight of polyethylene glycol diacrylate is 200-10,000.

Further, the thrombin-responsive cross-linking agent includes a thrombin-cleavable substrate, polypeptide or aptamer fragment, and at least two cross-linkable unsaturated bonds.

Further, the fibrinolytic activity molecule is selected from at least one of tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA) and streptokinase (SK) .

Further, in the prepolymerization solution, the concentration of fibrinolytic active molecules is 0.02 mg/mL to 20 mg/mL. Furthermore, in the prepolymerization solution, the concentration of fibrinolytic active molecules is 0.05 mg/mL to 10 mg/mL.

In one embodiment, the solvent is protein buffer or water. When the solvent is a protein buffer, the pH range of the protein buffer is 6-10, preferably 7-9.

In one embodiment, the photosensitizer is selected from at least one of a hydrogen abstraction type photoinitiator (eg, benzophenone) and a cleavage type photoinitiator (eg, photoinitiator 2959).

Further, in the prepolymerization solution, the concentration of the thrombin-responsive cross-linking agent is 0.05 mg/mL to 30 mg/mL. Furthermore, in the prepolymerization solution, the concentration of the thrombin-responsive cross-linking agent is 0.1 mg/mL to 10 mg/mL.

Further, in the prepolymerization solution, the mass concentration of the photosensitizer is 0.1% to 2.0%. Further, in the prepolymerization solution, the mass concentration of the photosensitizer is 0.5% to 1.0%.

S20, coating the prepolymerized solution on the surface of the substrate, and obtaining a hydrogel coating after photocuring.

The coating methods include, but are not limited to, dip coating, brush coating, spray coating, and the like.

Further, in the photocuring process, the ultraviolet irradiation time is 1s˜60s, and the range of the illumination intensity is 5mw/cm ² ˜50mw/cm ² .

By applying the above-mentioned preparation method of the hydrogel coating according to the technical solution of the present invention, the system can encapsulate fibrinolytic active molecules while forming the hydrogel coating by cross-linking, and form a hydrogel coating with thrombin responsiveness. Among them, polyethylene glycol diacrylate provides good resistance to non-specific protein adsorption for the hydrogel coating. Since the hydrogel coating contains both non-degradable polyethylene glycol diacrylate and a thrombin-degradable thrombin-responsive cross-linking agent, the hydrogel is free from thrombin-responsive release of fibrinolytic active molecules. The coating will not degrade completely and will continue to provide the surface with resistance to protein adsorption. In this way, the thrombus-stressed fibrinolytic function can be achieved, and the biological inertness can be maintained in a non-thrombotic environment. The above work realizes a simple and efficient responsive thrombolytic hydrogel coating, which has a good application prospect in the actual fibrinolytic active molecule drug-loaded coating.

A coated article of one embodiment includes a substrate and the above-described hydrogel coating, the hydrogel coating being applied to the surface of the substrate.

In one embodiment, the substrate is a medical device. In the present invention, "medical device" should be interpreted in a broad sense. A medical device can be an implantable device or an extracorporeal device. The device can be used temporarily for a short period of time or implanted permanently for a long period of time. Examples of suitable medical devices are vascular stents, sheaths, central venous catheters, hemodialysis lines and the like.

In one embodiment, the material of the substrate is organic polymer, metal or metal oxide. Examples include polyethylene, polypropylene, polycarbonate, polyvinyl chloride, polyurethane, polydimethylsiloxane, nylon, polyethylene terephthalate, gold, stainless steel, or nickel-titanium alloys. Of course, the material of the substrate is not limited to this, and can also be inorganic non-metals, such as medical ceramics.

The above-mentioned coated product includes the above-mentioned simple and efficient responsive thrombolytic hydrogel coating, which not only realizes the function of thrombus stress-induced fibrinolysis, but also maintains biological inertness in a non-thrombotic environment. It has good application prospects in terms of layers.

Referring to the above implementation content, in order to make the technical solutions of the present application more specific, clear and easy to understand, the technical solutions of the present application are now given as examples, but it should be noted that the content to be protected by the present application is not limited to the following examples.

Example 1

Combine 100 μL of tissue plasminogen activator (t-PA) at a concentration of 0.5 mg/mL with 100 μL of a peptide crosslinker (methacryloyl-Gly-dPhe-Pro-Arg-Gly- Phe-Pro-Ala-Gly-Gly-Lys-methacryloyl) was added to the brown vial, after which 5 μL of PEGDA (Mn=500) at a concentration of 1 g/mL and 50 μL of Irgacure 2959 (5 mg/mL) were added to the vial , mixed uniformly to obtain a prepolymerized solution.

The surface of the gold flakes was cleaned with "piranha" solution (H ₂ SO ₄ /H ₂ O ₂ =3/1, v/v) and then placed in a plasma generator for surface treatment for 5 minutes. 10 μL of the prepolymerization solution was dropped onto the treated gold flake surface with a pipette, and then the surface was irradiated with UV light for 30 s at room temperature to obtain a cross-linked hydrogel coating. After curing, the surface was washed 3 times with PBS (pH 7.4) to remove unreacted material remaining on the surface.

Example 2

Combine 100 μL of tissue plasminogen activator (t-PA) at a concentration of 0.5 mg/mL with 100 μL of a peptide crosslinker (methacryloyl-Gly-dPhe-Pro-Arg-Gly- Phe-Pro-Ala-Gly-Gly-Lys-methacryloyl) was added to the brown bottle, after which 25 μL of PEGDA (Mn=500) at a concentration of 1 g/mL and 30 μL of Irgacure 2959 (10 mg/mL) were added to the bottle , mixed uniformly to obtain a prepolymerized solution.

The surface of the gold flakes was cleaned with "piranha" solution (H ₂ SO ₄ /H ₂ O ₂ =3/1, v/v) and then placed in a plasma generator for surface treatment for 5 minutes. 10 μL of the prepolymerization solution was dropped onto the treated gold flake surface with a pipette, and then the surface was irradiated with UV light for 30 s at room temperature to obtain a cross-linked hydrogel coating. After curing, the surface was washed 3 times with PBS (pH 7.4) to remove unreacted material remaining on the surface.

Example 3

Combine 100 μL of tissue plasminogen activator (t-PA) at a concentration of 0.5 mg/mL with 100 μL of a peptide crosslinker (methacryloyl-Gly-dPhe-Pro-Arg-Gly- Phe-Pro-Ala-Gly-Gly-Lys-methacryloyl) was added to the brown bottle, after which 50 μL of PEGDA (Mn=500) at a concentration of 1 g/mL and 60 μL of Irgacure 2959 (5 mg/mL) were added to the bottle , mixed uniformly to obtain a prepolymerized solution.

The surface of the gold flake material was cleaned with a "piranha" solution (H ₂ SO ₄ /H ₂ O ₂ =3/1, v/v) and then placed in a plasma generator for surface treatment for 5 minutes. 10 μL of the prepolymerization solution was dropped onto the surface of the treated gold flake material with a pipette, and then the surface was irradiated with UV light for 30 s at room temperature to obtain a cross-linked hydrogel coating. After curing, the surface was washed 3 times with PBS (pH 7.4) to remove unreacted material remaining on the surface.

Example 4

Combine 100 μL of tissue plasminogen activator (t-PA) at a concentration of 0.5 mg/mL with 100 μL of a peptide crosslinker (methacryloyl-Gly-dPhe-Pro-Arg-Gly- Phe-Pro-Ala-Gly-Gly-Lys-methacryloyl) was added to the brown vial, after which 5 μL of PEGDA (Mn=500) at a concentration of 1 g/mL and 50 μL of Irgacure 2959 (5 mg/mL) were added to the vial , mixed uniformly to obtain a prepolymerized solution.

The surface of the polyurethane (PU) diaphragm was ultrasonically cleaned with absolute ethanol. 10 μL of the prepolymerization solution was dropped onto the cleaned polyurethane (PU) membrane surface with a pipette, and then the surface was irradiated with UV light for 30 s at room temperature to obtain a cross-linked hydrogel coating. After curing, the surface was washed 3 times with PBS (pH 7.4) to remove unreacted material remaining on the surface.

Example 5

Combine 100 μL of tissue plasminogen activator (t-PA) at a concentration of 0.5 mg/mL with 100 μL of a peptide crosslinker (methacryloyl-Gly-dPhe-Pro-Arg-Gly- Phe-Pro-Ala-Gly-Gly-Lys-methacryloyl) was added to the brown vial, followed by 50 μL of PEGDA (Mn=500) at a concentration of 100 mg/mL and 50 μL of Irgacure 2959 (5 mg/mL) , mixed uniformly to obtain a prepolymerized solution.

The surface of the gold flakes was treated by a "piranha" solution (H ₂ SO ₄ /H ₂ O ₂ =3/1, v/v) and then placed in a plasma generator for surface treatment for 5 minutes. 10 μL of the prepolymerization solution was dropped onto the treated gold flake surface with a pipette, and then the surface was irradiated with UV light for 30 s at room temperature to obtain a cross-linked hydrogel coating. After curing, the surface was washed 3 times with PBS (pH 7.4) to remove the residual unreacted material on the surface to obtain an anticoagulant coating.

Example 6

100 μL of tissue-type plasminogen activator (t-PA) at a concentration of 0.5 mg/mL was combined with 100 μL of a peptide crosslinker (methacryloyl-Gly-dPhe-Pro-Arg-Gly- Phe-Pro-Ala-Gly-Gly-Lys-methacryloyl) was added to the brown vial, followed by 50 μL of PEGDA (Mn=500) at a concentration of 100 mg/mL and 50 μL of Irgacure 2959 (5 mg/mL) , mixed uniformly to obtain a prepolymerized solution.

The polydimethylsiloxane (PDMS) membrane sheet was placed in a plasma processor for surface treatment for 5 minutes. 10 μL of the prepolymerization solution was dropped onto the treated membrane surface with a pipette, and then the surface was irradiated with UV light for 30 s at room temperature to obtain a cross-linked hydrogel coating. After curing, the surface was washed 3 times with PBS (pH 7.4) to remove the residual unreacted substances on the surface to obtain an anticoagulant coating.

Comparative Example 1

Mix 100 μL of tissue-type plasminogen activator (t-PA) with a concentration of 0.5 mg/mL, 100 μL of PEGDA (Mn=500) with a concentration of 1 g/mL, and 50 μL of Irgacure 2959 (5 mg/mL) to obtain a pre-prepared solution. polymerization solution.

The surface of the gold flakes was cleaned with "piranha" solution (H ₂ SO ₄ /H ₂ O ₂ =3/1, v/v) and then placed in a plasma generator for surface treatment for 5 minutes. 10 μL of the prepolymerization solution was dropped onto the treated gold flake surface with a pipette, and then the surface was irradiated with UV light for 30 s at room temperature to obtain a cross-linked hydrogel coating. After curing, the surface was washed 3 times with PBS (pH 7.4) to remove unreacted material remaining on the surface.

Performance Testing:

(1) The hydrogel coating of Comparative Example 1 and the hydrogel coatings of Examples 1 to 3 were characterized by scanning electron microscopy, respectively, and Figures 1(a) to 1(d) were obtained. It can be seen from Figure 1(a) to Figure 1(d) that the surface of the pure PEG hydrogel coating of Comparative Example 1 is relatively dense. With the increase of , the gel gradually appeared pores, and the size of the pores gradually increased. This is because PEGDA is the main component of the gel skeleton, and the reduction of its content will loosen the gel structure, thereby forming a macroporous structure.

Subsequently, the hydrogel coating of Comparative Example 1 and the hydrogel coating of Examples 1 to 3 were immersed in a 10 U/mL thrombin solution and incubated for 5 hours, respectively, and characterized by scanning electron microscopy. 1(e) to Figure 1(h). It can be seen from Figure 1(e) to Figure 1(h) that the surface density of the pure PEG gel coating of Comparative Example 1 did not change significantly after the action of thrombin, indicating that no degradation occurred. The pores on the surface of the hydrogel coating added with the polypeptide cross-linking agent were further enlarged and the structure became loose after the interaction with thrombin, but the structure of the gel was still retained, indicating that the gel was blocked by the thrombin due to the polypeptide cross-linking agent. Only partial degradation occurred after cutting.

(2) The encapsulation and release of t-PA in the hydrogel coating were studied by isotope labeling method.

The hydrogel coatings of Example 4 and Comparative Example 1 were incubated in PBS solution and thrombin solution (10 U/mL) for 5 hours, respectively, to obtain the release curves of t-PA, as shown in Figure 2(a) and Figure 2, respectively (b). It can be seen from Fig. 2(a) and Fig. 2(b) that the amount of t-PA encapsulated in the hydrogel coatings of Example 4 and Comparative Example 1 is about 1.33 μg/cm ² , and there is no significant difference between them. difference, indicating that the hydrogel structure has no significant effect on the loading of t-PA.

As can be seen from Figure 2(a), for the hydrogel coating containing the polypeptide cross-linking agent, t-PA was not released when soaked in PBS without thrombin, indicating that the t-PA-encapsulated hydrogel coating The layer is relatively stable, and the t-PA hardly escapes from the hydrogel by diffusion. In the presence of thrombin, t-PA was released, and the release amount showed a linear relationship with time, and there was no burst or delayed release, indicating that the hydrogel was uniformly and gradually degraded under the action of thrombin. When the ratio of Pep/PEGDA was 1/5, the release curve reached a plateau at the 5th hour, and the release was completed.

As can be seen from Figure 2(b), for the pure PEGDA gel coating, no release of t-PA occurred regardless of the presence or absence of thrombin.

(3) The adsorption of Fg on the substrate surface was studied by labeling Fg protein with Na ¹²⁵ I by the ICl method.

^125I -Fg and unlabeled Fg were mixed at a ratio of 1:49 and added to PBS to prepare a protein adsorption solution (1 mg/mL). The samples prepared before and after degradation in thrombin (10 U/mL) of Example 5 were immersed in the adsorption solution for 3 h at room temperature. Afterwards, the samples were washed 3 times with PBS, dried and transferred to clean centrifuge tubes. The amount of radiation on the surface was measured by a gamma counter, and the amount of protein adsorbed on the surface was obtained by calculation.

As shown in Figure 3, the pure PEGDA hydrogel coating of Comparative Example 1 reduced fibrinogen by about 57% compared to the unmodified gold surface. In Example 5, after the introduction of the polypeptide cross-linking agent, the amount of protein adsorption decreased further, mainly due to the loose structure of the gel coating caused by the introduction of the polypeptide, and the exposure of more PEG segments was beneficial to anti-protein adsorption. The amount of protein adsorbed after degradation was even lower than that before degradation, because the degradation caused more PEG segments to be exposed, thereby further enhancing the repellency to fibrinogen, a strongly adhesive protein.

(4) Judging the formation and dissolution of fibrin according to the change of the absorbance of the solution.

The t-PA loaded hydrogel coatings of Example 6 and Comparative Example 1 were incubated in plasminogen solution (0.2 mg/mL) in the presence or absence of thrombin (10 U/mL) at 37°C for 5 Hour. Then take 100 μL of the solution and transfer it to a 96-well plate. 100 μL of fibrinogen (2 mg/mL) and 10 μL of PBS were added to the wells of the plate. For samples without thrombin, a predetermined volume of PBS was replaced with 10 [mu]L of thrombin solution (100 U/mL). Under the condition of 37°C, the change of absorbance at 340nm with time was measured, and the test time was 80 minutes, and Figure 4 was obtained.

As shown in Figure 4, for the pure PEGDA hydrogel coating of Comparative Example 1, the absorbance value increased rapidly and then reached a plateau, indicating that a stable fibrin clot was formed without fibrinolysis. For the hydrogel coating containing the polypeptide cross-linking agent of Example 6, the absorbance value increased rapidly and then decreased rapidly until reaching the baseline, indicating that the t- PA rapidly forces the resulting fibrinolysis to dissolve.

The technical features of the above-described embodiments can be combined arbitrarily. In order to simplify the description, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present application, and the descriptions thereof are relatively specific and detailed, but should not be construed as a limitation on the scope of the patent. It should be noted that, for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the scope of protection of the present application should be determined by the appended claims.

Claims (10)

1. A coating composition is characterized in that, comprises the following components according to parts by mass:

   
2. coating composition according to claim 1, is characterized in that, comprises the following components according to mass fraction:

   
3. The coating composition of claim 1, wherein the polyethylene glycol diacrylate has a molecular weight of 100-20,000.
4. The coating composition according to claim 1, wherein the fibrinolytic activity molecule is selected from at least one of tissue-type plasminogen activator, urokinase-type plasminogen activator and streptokinase .
5. The coating composition according to claim 1, wherein the solvent is a protein buffer or water.
6. A hydrogel coating, characterized in that, the hydrogel coating is obtained by curing the coating composition according to any one of claims 1 to 5.
7. A preparation method of the hydrogel coating described in claim 6, is characterized in that, comprises the steps:

   Dissolve polyethylene glycol diacrylate, thrombin-responsive cross-linking agent, fibrinolytic active molecule and photosensitizer in a solvent, and mix uniformly to obtain a prepolymerized solution;

   The prepolymerized solution is coated on the surface of the substrate, and after photocuring, a hydrogel coating is obtained.
8. A coated product is characterized by comprising a substrate and the hydrogel coating of claim 6, the hydrogel coating being coated on the surface of the substrate.
9. The coated article of claim 8, wherein the substrate is a medical device.
10. The coated product according to claim 8, wherein the material of the substrate is polymer, metal or metal oxide.

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