Antibacterial, anticoagulant bifunctional coating and method of making and needle having same

Abstract

The application belongs to the technical field of medical materials, and particularly relates to an antibacterial and anticoagulant double-functional coating, a preparation method thereof and a needle head with the same, which comprises the following steps: S100, substrate material pretreatment; S200, PDPA coating preparation; S300, heparin grafting; and S400, NO loading; the antibacterial and anticoagulant double-functional coating prepared by the application has excellent antibacterial and anticoagulant functions, can be used for hemodialysis, can effectively inhibit arteriovenous needle head blockage and prevent bacterial infection, and is firmly attached and not easy to fall off.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of medical materials, and particularly relates to an antibacterial and anticoagulant dual-functional coating, a preparation method thereof, and a needle head with the coating. BACKGROUND

[0002] Hemodialysis is an extracorporeal blood purification method for treating renal failure, such as chronic renal failure, uremia and the like. Its role is to replace the lost kidney function, remove metabolic waste, excess water and electrolytes in the body, and maintain the stability of the body environment. In hemodialysis, the arteriovenous needle (i.e., the arterial needle and the venous needle) is a key device for establishing an extracorporeal blood circulation path. During the hemodialysis process, the patient's blood must be taken out of the body, cleaned of toxins and excess water by a dialyzer, and then returned to the body. This process mainly relies on two needles: the arterial needle (arterial needle) and the venous needle (venous needle). The arterial needle is inserted into one end of the vascular access (such as an arteriovenous fistula) and connected to the blood drawing line (arterial end) of the dialysis machine to draw blood from the body to the dialyzer. The venous needle is inserted into the other end of the same vascular access and connected to the return line (venous end) of the dialysis machine to return the dialyzed blood to the body. During the dialysis process, the arterial and venous needles are inserted into the high-flow access such as an internal fistula, and a blood flow rate of 200-400 mL / min is maintained to ensure the dialysis efficiency and enable the toxins, metabolic waste and excess water to be fully removed. Therefore, the arterial and venous needles play a "bridge" role in hemodialysis and are key components that connect the body's blood vessels and the extracorporeal dialysis system. They not only ensure the smooth circulation of blood, but also are the basis for effective and stable dialysis treatment.

[0003] However, during hemodialysis, when the arterial and venous needles come into contact with blood, plasma protein adsorption easily occurs on the surface of the needles, which in turn triggers the coagulation cascade reaction that regulates thrombus formation. The blood clots formed by the reaction can easily block the arterial and venous needles, leading to insufficient blood flow, reduced dialysis efficiency, and even interruption of dialysis, which requires reinsertion of the needles, delays treatment time, and increases the psychological and physiological burden on the patient. At the same time, in order to remove the thrombus, the puncture site may need to be frequently changed or a catheter may need to be used, which increases the risk of vascular access damage and the incidence of infection, bleeding and puncture-related complications. In addition, the blockage may require replacement of the needles, blood line and even the dialyzer, resulting in waste of consumables and increasing the economic burden on the patient and the medical institution. In order to prevent blockage, the dosage of anticoagulant may be increased, but this may lead to bleeding complications, especially for elderly patients or patients with comorbidities. Therefore, the blockage of the arterial and venous needles by blood clots not only affects the effectiveness of dialysis treatment, but also increases the complexity and risk of treatment.

[0004] In addition, dialysis patients need 2-3 times of dialysis per week, and hemodialysis patients are usually immunocompromised, and the needle is the portal of vascular access, and the skin is frequently punctured and exposed to blood vessels during dialysis. Once bacteria invade, it is easy to cause local or systemic infection, such as bacteremia, sepsis, endocarditis, etc., and may also cause inflammation of the skin at the puncture site, vascular access infection, and in severe cases, lead to internal fistula failure or the need for surgical replacement of the catheter. Therefore, the antibacterial function of the hemodialysis needle is an important guarantee for preventing infection and protecting the health of patients. It not only can improve the safety of the dialysis process, but also can reduce medical risks, reduce complications and hospitalization rates.

[0005] Therefore, developing an arteriovenous needle with antibacterial and anticoagulant functions is one of the technical problems to be solved by those skilled in the art. SUMMARY

[0006] The purpose of the present application is to solve the above-mentioned technical problems, and to provide an antibacterial and anticoagulant dual-function coating, a preparation method and application thereof.

[0007] Therefore, the present application provides a preparation method of an antibacterial and anticoagulant dual-function coating, comprising the steps of:

[0008] S100, pretreatment of the base material: after cleaning and drying the base material, it is ready for use;

[0009] S200, preparation of the PDPA coating: immerse the base material in an aqueous solution containing 0.1-100 mg / mL dopamine and 0.2-8 mmol / L Tris, and incubate in the dark for 12-50 h. Then clean and dry the base material. Then immerse the base material in an aqueous solution containing 0.3-10 mg / mL NaOH and 0.2-8 mg / mL PAH, and continue to incubate in the dark for 6-20 h. Then dry again to complete the preparation of the PDPA coating;

[0010] S300, heparin grafting: immerse the base material loaded with the PDPA coating in an aqueous solution containing 0.2-7 mg / mL heparin, 0.1-9 mg / mL EDC, 0.05-2 mg / mL NHS, 10-100 mg / mL NaCl and 5-18 mg / mL MES buffer, and incubate for 8-24 h. After the reaction, clean and dry the base material to obtain a base material loaded with PDPA-Hep;

[0011] S400, NO loading: the PDPA-Hep loaded substrate material is immersed in a solution containing 0.01-0.5 mol / L sodium methoxide, then placed in a NO reactor, and 1-15 bar of NO gas is introduced into the NO reactor, and incubated under a sealed condition for 30-120 h, and then the substrate material is washed and dried again to obtain a PDPA@NO-Hep coating loaded on the substrate material.

[0012] Further, in the step S100, the washing process of the substrate material includes:

[0013] the substrate material is immersed in acetone for ultrasonic cleaning, and the cleaning time is 5-30 min;

[0014] and / or, the substrate material is immersed in ethanol for ultrasonic cleaning, and the cleaning time is 5-30 min;

[0015] and / or, the substrate material is immersed in deionized water for ultrasonic cleaning, and the cleaning time is 5-30 min.

[0016] Further, in the step S100, the substrate material is mechanically polished before being washed.

[0017] Further, in the step S200, the incubation temperature is 30-45℃, and the washing liquid used for washing the substrate material is deionized water.

[0018] Further, in the step S300, the incubation temperature is 30-45℃, and the washing liquid used for washing the substrate material is deionized water.

[0019] Further, in the step S400, before introducing the NO gas into the NO reactor, 1-15 bar of argon is used to flush the NO reactor.

[0020] Further, in the step S400, after the reaction of introducing the NO gas into the NO reactor, 1-15 bar of argon is used to flush the substrate material again.

[0021] Further, in the step S400, after the PDPA@NO-Hep coating loaded substrate material is taken out, the substrate material is washed with anhydrous methanol.

[0022] In addition, the present application also provides an antibacterial and anticoagulant dual functional coating, which is a PDPA@NO-Hep coating prepared by the above preparation method.

[0023] In addition, the present application also provides a needle, which is coated with the above-mentioned PDPA@NO-Hep coating.

[0024] In addition, the application further provides a blood contact type medical device coated with the above-mentioned PDPA@NO-Hep coating.

[0025] The application has the advantages that the prepared antibacterial and anticoagulant dual-functional coating has excellent antibacterial and anticoagulant functions, can effectively inhibit needle blockage and prevent bacterial infection when used in blood contact type medical devices such as arteriovenous needles for hemodialysis, and the coating is firmly attached and not easy to fall off. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a real object diagram of each sample prepared in Example 1 of the application;

[0027] Figure 2 is a SEM image of the sample prepared in Example 1 of the application;

[0028] Figure 3 is a water contact angle diagram of the sample prepared in Example 1 of the application;

[0029] Figure 4 is a water contact angle statistical diagram of the sample prepared in Example 1 of the application;

[0030] Figure 5 is an amino loading amount statistical diagram of the sample prepared in Example 1 of the application;

[0031] Figure 6 is a NO release amount statistical diagram of the sample prepared in Example 1 of the application;

[0032] Figure 7 is a NO carrying amount statistical diagram of the sample prepared in Example 1 of the application;

[0033] Figure 8 is a heparin grafting amount statistical diagram of the sample prepared in Example 1 of the application;

[0034] Figure 9 is an infrared spectrum diagram of the sample prepared in Example 1 of the application;

[0035] Figure 10 is an XPS total spectrum diagram of the sample prepared in Example 1 of the application;

[0036] Figure 11 is a C1s spectrum diagram of the sample prepared in Example 1 of the application;

[0037] Figure 12 is a N1s spectrum diagram of the sample prepared in Example 1 of the application;

[0038] Figure 13 is the O1s spectrogram of the sample prepared in Example 1 of the present application;

[0039] Figure 14 is the S1s spectrogram of the sample prepared in Example 1 of the present application;

[0040] Figure 15 is the surface topography image of the sample prepared in Example 1 of the present application in the in-vitro simulation of hemodialysis circulation test;

[0041] Figure 16 is the culture result of E. coli and S. aureus on the surface of the sample prepared in Example 1 of the present application;

[0042] Figure 17 is the quantity statistical result of E. coli and S. aureus on the surface of the sample prepared in Example 1 of the present application;

[0043] Figure 18 is the morphology of E. coli and S. aureus on the surface of the sample prepared in Example 1 of the present application under SEM;

[0044] Figure 19 is the live and dead bacteria staining test result of the sample prepared in Example 1 of the present application;

[0045] Figure 20 is the percentage of live and dead bacteria of E. coli and S. aureus on the surface of the sample prepared in Example 1 of the present application;

[0046] Figure 21 is the APTT, PT and TT test result of the sample prepared in Example 1 of the present application;

[0047] Figure 22 is the cGMP concentration determination result of the sample prepared in Example 1 of the present application;

[0048] Figure 23 is the platelet adhesion and activation detection result of the sample prepared in Example 1 of the present application;

[0049] Figure 24 is the fluorescence intensity statistical result of the sample prepared in Example 1 of the present application;

[0050] Figure 25 is the platelet quantity determination result on the surface of the sample prepared in Example 1 of the present application;

[0051] Figure 26 is the platelet activation percentage determination result on the surface of the sample prepared in Example 1 of the present application;

[0052] Figure 27is the result of an in vivo anti-coagulation test of the sample prepared in Example 1 of the present application;

[0053] Figure 28 is the result of an in vivo anti-bacterial test of the sample prepared in Example 1 of the present application;

[0054] Figure 29 is a statistical graph of the amino load of the sample prepared in Example 2 of the present application;

[0055] Figure 30 is a statistical graph of the NO load of the sample prepared in Example 2 of the present application;

[0056] Figure 31 is a statistical graph of the heparin graft of the sample prepared in Example 2 of the present application;

[0057] Figure 32 is a statistical graph of the amino load of the sample prepared in Example 3 of the present application;

[0058] Figure 33 is a statistical graph of the NO load of the sample prepared in Example 3 of the present application;

[0059] Figure 34 is a statistical graph of the heparin graft of the sample prepared in Example 3 of the present application. DETAILED DESCRIPTION

[0060] The technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art belong to the scope of protection of the present application.

[0061] In the description of the present application, it should be noted that the terms used herein are only intended to describe the specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. For the convenience of description, the technologies, methods and devices known to those of ordinary skill in the art can not be discussed in detail, but should be considered as part of the authorized description. In all the examples shown and discussed herein, any specific value should be interpreted as merely exemplary, and not as a limitation. Therefore, other examples of the exemplary embodiments can have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0062] It should be noted that in this application, the terms "comprising", "including", or any other variant thereof are intended to cover a non-exclusive inclusion, so that a process, method, article, or apparatus that comprises a list of elements not only includes those elements, but also includes other elements not expressly listed or inherent to such process, method, article, or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or apparatus including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, but can also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method can be performed in an order different from that described, and various steps can also be added, omitted, or combined. In addition, the features described with reference to certain examples can be combined in other examples.

[0063] A method for preparing an antibacterial and anticoagulant bifunctional coating, comprising the steps of:

[0064] S100, pretreatment of the base material: after cleaning and drying the base material, it is ready for use;

[0065] S200, preparation of the PDPA coating: immerse the base material in an aqueous solution containing 0.1-100 mg / mL dopamine and 0.2-8 mmol / L Tris, incubate in the dark for 12-50 h, then clean and dry the base material; then immerse the base material in an aqueous solution containing 0.3-10 mg / mL NaOH and 0.2-8 mg / mL PAH, continue to incubate in the dark for 6-20 h, then dry again to complete the preparation of the PDPA coating;

[0066] S300, heparin grafting: immerse the base material loaded with the PDPA coating in an aqueous solution containing 0.2-7 mg / mL heparin, 0.1-9 mg / mL EDC, 0.05-2 mg / mL NHS, 10-100 mg / mL NaCl, and 5-18 mg / mL MES buffer, incubate for 8-24 h, after the reaction, clean and dry the base material to obtain the base material loaded with PDPA-Hep;

[0067] S400, NO loading: immerse the base material loaded with PDPA-Hep in a solution containing 0.01-0.5 mol / L sodium methoxide, then place it in a NO reactor, introduce 1-15 bar of NO gas into the NO reactor, and incubate under sealed conditions for 30-120 h, then clean and dry the base material again to obtain the PDPA@NO-Hep coating loaded on the base material.

[0068] Preferably, the process of preparing the PDPA coating can be repeated multiple times by immersing the substrate material into the aqueous solution containing 0.1-100 mg / mL dopamine and 0.2-8 mmol / L Tris, and incubating in the dark.

[0069] It should be noted that the PAH is the abbreviation of polyallylamine hydrochloride, which is a positively charged macromolecular polyelectrolyte. In the present application, it is used to form a positive layer on the PDPA layer to provide a good affinity interface for the subsequent grafting of negatively charged heparin.

[0070] The EDC used in the present application is the abbreviation of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, which is a water-soluble carbodiimide crosslinking agent. It can activate carboxyl groups and undergo condensation reaction with amino groups to promote the formation of amide bonds. In the present application, it is used to activate the carboxyl groups on the heparin molecules, so that they can covalently graft with the amino groups on the surface of PDPA or PAH.

[0071] The NHS used in the present application is the abbreviation of N-hydroxysuccinimide. In the present application, it is used in combination with EDC to stabilize the intermediate activated ester, improve the activation efficiency of carboxyl groups, and enhance the grafting reaction efficiency. Together with EDC, it promotes the efficient covalent immobilization of heparin on the surface of the PDPA coating.

[0072] The MES used in the present application is the abbreviation of 2-(N-morpholino) ethanesulfonic acid. In the present application, it is used as a buffer to provide a stable buffer environment, so that EDC / NHS can function at the optimal pH and control the pH conditions of the grafting reaction.

[0073] As some examples of the present application, the substrate material can be a polymeric material such as polyurethane (PU), polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), etc.

[0074] As some examples of the present application, the substrate material can also be a metal material such as stainless steel (316L series stainless steel, 420, 440C, 17-4PH, 2205, etc.), titanium alloy (Ti-6Al-4V), cobalt-chromium alloy (CoCr), etc.

[0075] As some examples of the present application, the substrate material can also be a silicon-based and ceramic material such as a silicone rubber material infusion tube, a catheter, a glass / silicon oxide substrate material biochip, a sensor, etc.

[0076] Further, in the step S100, the cleaning process of the substrate material includes:

[0077] The base material is immersed in acetone for ultrasonic cleaning, and the cleaning time is 5-30 min;

[0078] The base material is immersed in ethanol for ultrasonic cleaning, and the cleaning time is 5-30 min.

[0079] The base material is immersed in deionized water for ultrasonic cleaning, and the cleaning time is 5-30 min.

[0080] The specific cleaning times and the selection of cleaning solvents can be adjusted according to specific conditions. The surface of the cleaned base material should be free of surface contaminants and organic residues.

[0081] Further, in the step S100, before cleaning the base material, the base material is first mechanically polished to adjust the surface roughness of the base material, so that the subsequently prepared coating is easy to adhere.

[0082] Preferably, 800, 1000, or 1200 number of very fine sandpaper can be used for mechanical polishing.

[0083] Further, in the step S200, the incubation temperature is 30-45℃, and the cleaning solution used for cleaning the base material is deionized water.

[0084] Further, in the step S300, the incubation temperature is 30-45℃, and the cleaning solution used for cleaning the base material is deionized water.

[0085] Further, in the step S400, before introducing NO gas into the NO reactor, 1-15 bar of argon is used to flush the NO reactor; after introducing NO gas into the NO reactor for reaction, 1-15 bar of argon is used to flush the base material again.

[0086] As some examples of the present application, in the step S400, before introducing NO gas into the NO reactor, 1-15 bar of argon is used to flush the NO reactor, and the flushing method can be: 5 minutes each time x 3 times, and then 10 minutes x 2 times.

[0087] As some examples of the present application, in the step S400, after introducing NO gas into the NO reactor for reaction, 2-10 bar of argon is used to flush the base material, and the flushing method can be: 5 minutes x 2 times, and 10 minutes x 2 times.

[0088] Further, in the step S400, after the base material loaded with the PDPA@NO-Hep coating is taken out, anhydrous methanol is used to clean the base material.

[0089] The application also provides an antibacterial and anticoagulant dual functional coating, which is a PDPA@NO-Hep coating prepared by the above preparation method.

[0090] The application also provides a needle coated with the above PDPA@NO-Hep coating.

[0091] As some examples of the application, the needle can be a arteriovenous needle for hemodialysis or other needles.

[0092] The application also provides a blood contact medical device coated with the above PDPA@NO-Hep coating.

[0093] As some examples of the application, the blood contact medical device can be a hemodialysis related device (such as a hemodialysis pipeline), an extracorporeal circulation system device (an extracorporeal circulation pipeline, a blood pump and an oxygenator surface), a vascular interventional device (a vascular catheter, a vascular stent, a balloon catheter and a blood purification column), a blood collection and transfusion device (a blood collection needle, a blood transfusion needle, a blood transfusion pipeline and a blood storage bag), an artificial organ and an auxiliary circulation device, etc.

[0094] The antibacterial and anticoagulant dual functional coating and the preparation method thereof are illustrated by specific examples as follows:

[0095] Example 1

[0096] Different state samples are prepared according to the following process:

[0097] (1) Pretreatment of 316L stainless steel substrate:

[0098] The 316 stainless steel substrate is mechanically polished using 1000 grit sandpaper. After polishing, the sample is ultrasonically cleaned in acetone, ethanol and deionized water respectively, each solution for 15 minutes, to remove surface contaminants and organic residues. The cleaned substrate is air dried or dried with nitrogen flow, ready for use. The cleaned 316L stainless steel substrate sample is called 316LSS group.

[0099] (2) Preparation of PDPA coating:

[0100] The polished 316L stainless steel substrate is placed in a 24-well plate with the front face upward, completely immersed in an aqueous solution containing 1 mg / mL dopamine and 1 mmol / L Tris; the sample is incubated at 37°C in the dark for 24 hours; after the reaction, the substrate is ultrasonically cleaned with deionized water to remove unbound residues and dried; the dried sample is called PD group.

[0101] After complete drying, the samples were immersed in an aqueous solution containing 2 mg / mL NaOH and 2 mg / mL PAH, and incubated at 37 °C in the dark for 12 h. Finally, the coating process was completed by drying again. The treated samples were named as PDPA group.

[0102] (3) Heparin grafting process:

[0103] The PDPA-coated samples were immersed in an aqueous solution containing 2 mg / mL heparin (HEP), 2 mg / mL EDC, 0.5 mg / mL NHS, 40 mg / mL NaCl and 9.6 mg / mL MES buffer (pH 5.6), and incubated at 37 °C for 12 h. After reaction, the samples were rinsed with deionized water and dried. The treated samples were named as PDPA-Hep group.

[0104] (4) NO loading process:

[0105] The NO loading process used a high-pressure NO treatment method. Specifically, the PDPA and PDPA-Hep samples were first immersed in a 0.05 mol / L methoxy sodium solution, and then placed in a custom-made stainless steel NO reactor. The reactor was flushed with 6 bar argon gas (5 min x 3 times, then 10 min x 2 times) to completely remove residual oxygen and moisture. Then, 5 bar pure NO gas was introduced into the reactor and incubated under sealed conditions for 72 h. After reaction, the reactor was again flushed with 6 bar argon gas (5 min x 2 times, 10 min x 2 times). After the samples were removed, they were thoroughly rinsed with anhydrous methanol and dried in a fume hood. The resulting NO-loaded samples were named as PDPA@NO group and PDPA@NO-Hep group, respectively.

[0106] Sample detection:

[0107] The samples prepared in Example 1 above were detected and analyzed, including: 316LSS group sample, PD group sample, PDPA group sample, PDPA-Hep group sample, PDPA@NO group sample, and PDPA@NO-Hep group sample. One or more samples can be detected and analyzed as needed for each detection:

[0108] (I) The actual sample images of the samples obtained in Example 1 above were observed, and the actual sample images of each sample were obtained as shown in Figure 1 According to Figure 1 we can get:

[0109] 1) For the PD group sample, the dopamine coating generally forms a thin film on the metal surface through a self-polymerization reaction, with strong adhesion and biocompatibility; the film formed by dopamine on the surface may exhibit certain color changes, which may be due to the interaction of the polymer film formed after the self-polymerization of dopamine with light at different thicknesses.

[0110] 2) For the PDPA group sample, on the basis of the dopamine coating, the chemical structure of the coating is changed, resulting in a change in color, and it is speculated that PDPA may change the surface microstructure, thereby affecting its optical properties.

[0111] 3) For the PDPA-Hep group sample and the PDPA@NO group sample, NO (nitric oxide) and heparin (HEP) are loaded on the PDPA coating, which may further change the surface chemical properties of the coating. The loading of NO and HEP may cause chemical reactions on the surface of the coating, changing its color. Among them, NO may cause the surface to present yellow or light yellow, and the loading of heparin may bring similar color changes.

[0112] 4) For the PDPA@NO-Hep group sample, when NO and HEP are loaded at the same time, a complex synergistic effect may occur, resulting in more significant changes in the color of the coating, and the yellow tone of the coating may be due to the synergistic effect of the two substances, reflecting their common influence on the surface of the coating.

[0113] (II) The samples obtained in Example 1 above were placed under a scanning electron microscope for observation, and the surface morphology of the samples after different coating treatments was observed, and the SEM images of the samples are shown in Figure 2 , and it can be known from Figure 2 that:

[0114] 1) The 316LSS group sample is 316 stainless steel surface without coating treatment, which presents a relatively smooth morphology.

[0115] 2) The PDPA group sample is treated with PDPA coating, and the surface appears obvious spherical particles, which is a typical structure of polydopamine coating.

[0116] 3) The surface morphology of the PDPA@NO group sample treated with PDPA coating and nitric oxide (NO) loading has no significant change.

[0117] 4) PDPA-Hep group sample: the surface morphology of the PDPA coating and heparin (Hep) loading treatment has no significant change.

[0118] 5) PDPA@NO-Hep group sample: PDPA coating is loaded with nitric oxide and heparin at the same time, and the morphology has no significant change.

[0119] (III) The water contact angle of the sample obtained in the above Example 1 was detected, and the water contact angle statistical diagram shown in FIG. 2 was obtained. According to FIG. 2, it can be known that: Figure 3 Figure 4 Figure 3 Figure 4

[0120] 1) 316LSS group sample: The untreated 316 stainless steel (control group) showed a higher contact angle (about 80°), indicating that it was a hydrophobic surface, and the water droplets would not spread easily.

[0121] 2) PDPA group sample: The PDPA coating surface was highly hydrophilic, and the contact angle decreased significantly to about 30°.

[0122] 3) PDPA@NO group sample: After NO loading treatment, the water contact angle increased slightly to about 35°, indicating that the loading of NO might slightly reduce the hydrophilicity.

[0123] 4) PDPA-Hep group sample: The contact angle after loading heparin was 9.5°, showing extremely strong hydrophilicity, which was beneficial to the interaction with biological fluids.

[0124] 5) PDPA@NO-Hep group sample: The contact angle after loading NO and heparin was 16°, and the hydrophilicity was relatively strong, but slightly worse than when heparin was loaded alone, which might be due to the synergistic effect of the two on the surface properties.

[0125] (IV) The amino loading amount of the sample obtained in the above Example 1 was detected, and the amino loading amount statistical diagram shown in FIG. 3 was obtained. According to FIG. 3, it can be known that: Figure 5 Figure 5

[0126] 1) PDPA group sample: The amino loading amount of the PDPA coating was high, about 300 nmol / cm2, which proved the successful preparation of the PDPA coating. PDPA generally has good hydrophilicity and chemical stability, and can effectively load amino molecules to increase the surface functionality.

[0127] 2) PDPA@NO group sample and PDPA-Hep group sample: After loading NO or heparin, the amino loading amount changed, and the amino loading amount of the PDPA@NO and PDPA-Hep coatings decreased compared to the pure PDPA coating, which indicated that the loading of NO and heparin was achieved through amino groups.

[0128] 3) PDPA@NO-Hep group sample: The amount of amino groups decreased again, indicating that the loading of NO and heparin might further consume the amino groups of the PDPA coating, indirectly proving the successful preparation of the coating.

[0129] ​​​​​​(five) The NO release amount, NO carrying amount and heparin grafting amount of the sample obtained in the above embodiment 1 were detected, and the NO release amount statistical chart as shown in Figure 6 , the NO carrying amount statistical chart as shown in Figure 7 , and the heparin grafting amount statistical chart as shown in Figure 8 were obtained, wherein the heparin grafting amount was determined by qcm-d, and therefore the base material was gold. According to Figure 6 and 7 , it can be known that:

[0130] 1) 316L SS group sample: the untreated 316 stainless steel almost does not release NO;

[0131] 2) PDPA group sample: the PDPA coating almost does not release NO;

[0132] 3) PDPA@NO group sample: the NO-loaded coating significantly increases the NO release amount, indicating that the NO loading is successful;

[0133] 4) PDPA-Hep group sample: almost no NO is released;

[0134] 5) PDPA@NO-Hep group sample: this coating simultaneously loads NO and heparin, and the grafting of heparin consumes a certain amount of surface amino groups, so that the total NO release amount is lower than that of the PDPA@NO group; in addition, due to the presence of the heparin layer on the surface, the exchange of water molecules may be inhibited to some extent, so that the NO release behavior is more gentle. Specifically, heparin can inhibit the rate of water molecules penetrating into the coating by changing the surface chemical structure of the coating, thereby reducing the burst release rate of NO. Heparin not only helps to increase the hydrophilicity and anticoagulation effect of the surface, but also can regulate the NO release to be more gentle.

[0135] (six) The infrared spectrum of the sample obtained in the above embodiment 1 was detected, and the infrared spectrum as shown in Figure 7 was obtained, according to Figure 9 , it can be known that:

[0136] 1) The PDPA group sample (orange line) has:

[0137] O-H stretching vibration (about 3500 cm -1 ): The sample shows obvious O-H stretching vibration absorption peak, indicating that there is -OH (hydroxyl) functional group in the molecule, which usually means that PDPA has strong hydrophilicity.

[0138] C-H stretching vibration (about 3000 cm -1 ): The C-H absorption peak of PDPA is also obvious, indicating that it contains aliphatic or aromatic C-H bond.

[0139] C=O stretching vibration (about 1700 cm -1 ): In the PDPA sample, the C=O absorption peak near 1700 cm -1 indicates that it may contain functional groups such as ketones, aldehydes or esters in its molecular structure.

[0140] Aromatic ring C=C stretching vibration (about 1600 cm -1 ): PDPA shows typical absorption peaks of aromatic ring C=C vibration, indicating that it contains aromatic ring structure.

[0141] 2) PDPA-Hep group sample (purple line) exists:

[0142] O-H and N-H stretching vibration (about 3400 cm -1 ): In the PDPA-Hep sample, the O-H and N-H stretching vibration absorption peak becomes more significant, indicating that heparin (Hep) may be introduced, and the amino and hydroxyl groups in heparin participate in the formation of hydrogen bonds.

[0143] C-H stretching vibration (about 3000 cm -1 ): This peak is related to the stretching vibration of aliphatic or aromatic C-H bond, and the C-H absorption peak in PDPA-Hep sample is similar to that in PDPA.

[0144] C=O and N=O stretching vibration (about 1700 cm -1 , 1550 cm -1 ): The stretching vibration peak of C=O appears in PDPA-Hep, which may be related to the esterification or other carbonyl structure in heparin.

[0145] Aromatic ring C=C stretching vibration (about 1600 cm -1 ): The absorption peak of aromatic ring in PDPA-Hep remains at 1600 cm -1 , indicating that the aromatic structure is not significantly affected.

[0146] 3) PDPA@NO group sample (green line) exists:

[0147] O-H stretching vibration (about 3500 cm -1 ): In the PDPA@NO sample, the intensity of O-H stretching vibration peak is significantly reduced, indicating that the introduction of NO may affect the existence or interaction of hydroxyl groups.

[0148] C-H stretching vibration (about 3000 cm -1 ): The absorption peak of C-H does not change significantly in this sample, indicating that the aliphatic part in the structure of PDPA remains unchanged.

[0149] C=O stretching vibration (about 1700 cm-1 ) and N=O stretching vibration (about 1550 cm -1 ): 1700 cm -1 ): The C=O absorption peak is similar to PDPA, but the N=O peak at 1550 cm -1 is more prominent, indicating that the introduction of NO enhances the influence of the nitro functional group.

[0150] Aromatic ring C=C stretching vibration (about 1600 cm -1 ): The C=C stretching vibration peak of the aromatic ring is unchanged, indicating that the structure of the aromatic ring is not disturbed.

[0151] 4) The PDPA@NO-Hep group sample (red line) exists:

[0152] O-H and N-H stretching vibration (about 3500 cm -1 , 3400 cm -1 ): In the PDPA@NO-Hep sample, the O-H and N-H stretching vibration peaks become more complex. It may be due to the combined effect of NO and heparin, resulting in the enhancement of hydrogen bond interaction.

[0153] C-H stretching vibration (about 3000 cm -1 ): This peak is similar to the absorption peak of C-H stretching vibration, showing that the aliphatic structure in the sample has not changed significantly.

[0154] C=O stretching vibration (about 1700 cm -1 ): The C=O peak remains strong in this sample, indicating that ester or ketone functional groups still exist in the structure.

[0155] N=O stretching vibration (about 1550 cm -1 ) and S=O stretching vibration (about 1300 cm -1 ): The N=O peak at 1550 cm -1 is more prominent, indicating that the interaction between NO and heparin may introduce more NO groups. The S=O stretching vibration peak at 1300 cm -1 indicates that the sulfate group of heparin may be involved in the interaction with other functional groups.

[0156] Aromatic ring C=C stretching vibration (about 1600 cm -1 ): The C=C vibration absorption peak of the aromatic ring is consistent with the previous samples, remaining at 1600 cm -1 .

[0157] In summary, the PDPA sample (orange line) shows typical O-H, C-H, C=O and aromatic C=C absorption peaks, indicating that the molecule mainly contains -OH, C-H and aromatic ring structures.

[0158] The PDPA-Hep sample (purple line) shows significant changes in the O-H and N-H vibration regions, indicating that the introduction of heparin increases the amino and hydroxyl functional groups.

[0159] The PDPA@NO sample (green line) shows a decrease in O-H absorption and an increase in N=O vibration after the introduction of NO groups, indicating that the introduction of NO enhances the characteristic absorption of nitro compounds.

[0160] The PDPA@NO-Hep sample (red line) is the result of the combined action of NO and heparin, and the peaks of O-H and N-H are enhanced, while the absorption of S=O and N=O also becomes more obvious, indicating that the interaction of NO and heparin enhances the characteristic absorption of these functional groups.

[0161] (Seven) The samples obtained in the above Example 1 were subjected to XPS detection, and the XPS total spectrum as shown in Figure 10 was obtained. Figure 10 According to the above,

[0162] The PDPA@NO-Hep sample shows a high degree of oxidation on the surface and contains significant nitrogen and sulfur groups, indicating that the material may have been surface modified by NO and heparin.

[0163] The XPS spectrum shows that the PDPA@NO-Hep sample has the most complex surface chemical properties, possibly due to the combination of NO and heparin.

[0164] (Eight) The samples obtained in the above Example 1 were subjected to surface carbon element 1s orbital electron (C1s) energy analysis by X-ray photoelectron spectroscopy, and the C1s spectrum as shown in Figure 11 was obtained. Figure 11 According to the above,

[0165] 1) The PDPA@NO-Hep sample has significant intensity on the C-C peak (~26.71%) and C-O peak (~25.36%);

[0166] 2) The PDPA-Hep sample shows slightly higher C-C peak (~27.23%) and C-O peak (~24.48%);

[0167] 3) The PDPA@NO sample has a clear C-C peak (~33.41%), but the C-O peak intensity is low (~24.13%);

[0168] 4) The PDPA@NO-Hep group sample also showed a larger C-C peak (~33.41%) and a lower C-O peak (~23.57%);

[0169] These differences indicate that the PDPA@NO-Hep group sample has more oxidized groups on the surface than the PDPA and PDPA@NO group samples.

[0170] (Nine) The energy of the 1s orbital electron (N1s) of the nitrogen element on the surface of the sample obtained in the above Example 1 was analyzed by X-ray photoelectron spectroscopy, and the N1s spectrum as shown in FIG. 6 was obtained. The N1s spectrum provides information about nitrogen-containing groups, and according to Figure 12 , it can be known that: Figure 12

[0171] 1) The PDPA@NO-Hep group sample showed a small peak at ~398.5 eV, representing N=O / N-O (5.16%), and a peak at 399.5 eV corresponding to NH2 (~6.61%);

[0172] 2) The PDPA@NO group sample also has a similar N=O / N-O peak;

[0173] 3) The PDPA-Hep group sample and the PDPA group sample only showed the NH2 peak;

[0174] This indicates that the chemical environment of the PDPA@NO-Hep group sample and the PDPA@NO group sample can be different from that of the PDPA-Hep group sample and the PDPA group sample, possibly due to the introduction of NO-related groups.

[0175] (Ten) The energy of the 1s orbital electron (O1s) of the oxygen element on the surface of the sample obtained in the above Example 1 was analyzed by X-ray photoelectron spectroscopy, and the O1s spectrum as shown in FIG. 7 was obtained. The O1s spectrum shows the oxygen-containing groups on the surface, and according to Figure 13 , it can be known that: Figure 13

[0176] 1) The PDPA@NO-Hep group sample showed a significant C-O peak (~29.28%) and a small N-O peak (~1.61%);

[0177] 2) The C-O peak intensity of the PDPA-Hep group sample was ~23.14%, and the N-O peak was small (~3.2%);

[0178] 3) The PDPA@NO group sample showed similar C-O (~30.88%) and N-O (~3.2%) distributions;

[0179] 4) The C-O peak intensity of the PDPA group sample was ~20.42%, and the N-O peak was small (~2.88%).​​

[0180] This indicates that the PDPA@NO-Hep group sample has the most oxygen groups, while the oxygen content of PDPA is the lowest.

[0181] (Eleven) The sample obtained in the above Example 1 was subjected to energy analysis of 1s orbital electrons (S1s) of surface sulfur elements by X-ray photoelectron spectroscopy, and a S1s spectrum as shown in FIG. 11 was obtained. The S1s spectrum shows the presence of sulfur-containing groups, and according to Figure 14 Figure 14 It can be known that:

[0182] 1) The PDPA@NO-Hep group sample and the PDPA-Hep group sample respectively show small OSO3- peaks (0.28% and 0.61%);

[0183] 2) The PDPA@NO group sample and the PDPA group sample do not show significant sulfur peaks.

[0184] This indicates that PDPA@NO-Hep and PDPA-Hep contain sulfur groups related to heparin or the modification process, while PDPA and PDPA@NO do not.

[0185] (Twelve) The sample obtained in the above Example 1 was subjected to an in vitro simulation of hemodialysis circulation test, which was carried out at 37°C, using PBS biological buffer, a needle flushing flow rate of 250 mL / min to detect the bonding strength of the needle coating, and the surface morphology of the sample at different times was observed, and the images as shown in FIG. 12 were obtained. According to Figure 15 Figure 15 It can be known that:

[0186] 1) In the initial state (i.e. when the flushing time is 0h):

[0187] The surface of the 316 LSS group sample without coating shows the typical texture and roughness of metal, and there may be fine scratches and oxide layers. The specific surface structure can help to evaluate the corrosion resistance and biocompatibility of the material when it is not treated.

[0188] The polydopamine coating in the PDPA group sample shows some small granular or spherical structures in the enlarged image

[0189] The nitric oxide-loaded polydopamine coating in the PDPA@NO group sample shows similar structures in the enlarged image.

[0190] The heparin-loaded polydopamine coating in the PDPA-Hep group sample shows similar structures.

[0191] ​​The PDPA@NO-Hep group sample showed similar structure of the nitric oxide and heparin double-loaded polydopamine coating in the enlarged image.

[0192] 2) After flushing the needle with PBS at 37°C for 4 h at a flow rate of 250 mL / min:

[0193] The coating of the PDPA group sample was found to be relatively complete.

[0194] The coating of the PDPA-Hep group sample was found to be relatively complete.

[0195] Although the coating surface of the PDPA@NO group sample and the PDPA@NO-Hep group sample showed slight roughening and granulation, the coating did not show large-scale damage or peeling, and had good stability.

[0196] 3) After flushing the needle with PBS at 37°C for 24 h at a flow rate of 250 mL / min:

[0197] The coating of the PDPA group sample and the PDPA-Hep group sample was obviously swollen, while the coating of the PDPA@NO group sample and the PDPA@NO-Hep group sample was still uniformly distributed on the surface of the needle. Although the surface showed roughening and granulation, the coating did not show large-scale damage or peeling, and had good stability.

[0198] (Thirteen) The samples obtained in Example 1 were subjected to antibacterial performance tests, and the effects of different coating materials on the antibacterial performance of E. coli and S. aureus were studied, and the results are shown in Figures 16-20

[0199] Bacterial growth inhibition experiment: Figure 16 The culture results of E. coli and S. aureus on the control group (316 LSS) and different surface coating materials (PDPA, PDPA@NO, PDPA-Hep, PDPA@NO-Hep) were shown. It was found that the surface coating (especially PDPA@NO-Hep) significantly inhibited the growth of bacteria, and the number of bacteria of the PDPA@NO-Hep group was the least.

[0200] Bacterial number count (CFU / ml): Figure 17 The antibacterial effect of different coating materials on E. coli and S. aureus was shown, and the PDPA@NO-Hep group significantly reduced the number of bacteria, showing the best antibacterial performance compared with other groups.

[0201] Scanning electron microscope (SEM) image: According to​Figure 18 The morphological changes of E. coli and S. aureus on different coating surfaces can be seen. Among them, the PDPA@NO-Hep coating significantly reduces the adhesion of bacteria, and the morphological changes of the bacteria are significant, indicating that the surface has antibacterial function.

[0202] Live and dead bacteria staining test: the bactericidal effect of different coatings on E. coli and S. aureus was evaluated using live and dead bacteria staining method, and the results are shown in Figure 19 , wherein the PDPA@NO-Hep group shows obvious bacterial death, and green represents live bacteria and red represents dead bacteria.

[0203] Percentage of live and dead bacteria: the percentage of live and dead bacteria of E. coli and S. aureus on different material surfaces is shown in Figure 20 , according to Figure 20 , it can be seen that: the PDPA@NO-Hep group significantly improves the mortality of bacteria, indicating that the material has good antibacterial activity.

[0204] (14) The sample obtained in Example 1 above was subjected to anticoagulation function test, and the influence of different coating materials on blood coagulation function, cGMP concentration and platelet reaction was studied, and the results are shown in Figures 21-26 .

[0205] APTT, PT and TT test results: the influence of different material surfaces (316 LSS, PDPA, PDPA@NO, PDPA-Hep, PDPA@NO-Hep) on the coagulation time of plasma is shown in Figure 21 , wherein APTT is prolonged, and PDPA@NO-Hep significantly improves the anticoagulation effect; PT and TT do not change significantly between different groups (ns means no significant difference).

[0206] cGMP concentration determination results are shown in Figure 22 : By detecting the cGMP concentration, it is shown that the cGMP concentration of PDPA@NO and PDPA@NO-Hep groups is significantly higher than that of other groups, suggesting that the released NO of the surface material has activity in inducing platelet reaction.

[0207] Figure 23 is the sample platelet adhesion and activation detection result prepared in Example 1 of the present application, wherein the upper row indicates the platelet adhesion condition shown by the green fluorescence image, it can be seen that PDPA@NO-Hep significantly reduces the adhesion of platelets; the middle row indicates the corresponding SEM image, showing the morphological difference of platelets on different surfaces; the lower row indicates the SEM magnified image.

[0208] The platelet fluorescence intensity measurement results of the sample surface treated in each group are shown inFigure 24 The results show that PDPA@NO-Hep significantly reduces the fluorescence intensity of platelets, showing lower platelet adhesion.

[0209] The results of the determination of the number of platelets on the surface of different materials are shown in Table 2. Figure 25 As can be seen from Table 2, the PDPA@NO-Hep group shows fewer platelets, indicating its inhibitory effect on platelets. Figure 25 The results of the evaluation of the degree of platelet activation are shown in Table 3.

[0210] As can be seen from Table 3, the PDPA@NO-Hep group has a significantly lower percentage of platelet activation, indicating that the surface has an anti-platelet activation effect. Figure 26 Figure 26 The results of the evaluation of the degree of platelet activation are shown in Table 3.

[0211] (Fifteen) The sample obtained in Example 1 above was subjected to an in vivo anticoagulant function test, and a semi-in vivo blood circulation test was performed on New Zealand white rabbits, and the test results are shown in Table 4. Figure 27 As can be seen from Table 4, Figure 27 Compared with other samples, the in vivo anticoagulant function of the PDPA@NO-Hep group treated by the present application is significantly improved.

[0212] (Sixteen) The sample obtained in Example 1 above was subjected to an in vivo antibacterial test by subcutaneous implantation in rats, and the test results are shown in Table 5.

[0213] As can be seen from Table 5, Figure 28 Figure 28 Compared with other samples, the in vivo antibacterial performance of the PDPA@NO-Hep group treated by the present application is significantly improved.

[0214] Example 2

[0215] The samples in different states were prepared according to the following process:

[0216] (1) Pretreatment of 316L stainless steel substrate:

[0217] The 316 stainless steel substrate was mechanically polished using 1000 grit sandpaper. After polishing, the sample was ultrasonically cleaned in acetone, ethanol and deionized water, respectively, for 15 minutes for each solution to remove surface contaminants and organic residues. The cleaned substrate was air dried or dried with nitrogen flow, ready for use. The cleaned 316L stainless steel substrate sample was designated as the 316LSS group.

[0218] (2) Preparation of PDPA coating:

[0219] (2) Preparation of PDPA coating:

[0220] ​​The polished 316L stainless steel substrates were placed in a 24-well plate with the front side facing up and completely immersed in an aqueous solution containing 0.3 mg / mL dopamine and 0.5 mmol / L Tris; the samples were incubated at 37 °C in the dark for 24 hours; after the reaction, the substrates were ultrasonically cleaned with deionized water to remove unbound residues, and the samples were again completely immersed in an aqueous solution containing 0.3 mg / mL dopamine and 0.5 mmol / L Tris; the samples were incubated at 37 °C in the dark for 24 hours; and dried, the dried sample was designated as the PD group;

[0221] After complete drying, the samples were immersed in an aqueous solution containing 0.5 mg / mL NaOH and 0.2 mg / mL PAH, and incubated at 37 °C in the dark for 20 hours, and finally, dried again to complete the coating process, the treated sample was designated as the PDPA group.

[0222] (3) Heparin grafting process:

[0223] The PDPA-coated samples were immersed in an aqueous solution containing 0.2 mg / mL heparin (HEP), 0.1 mg / mL EDC, 0.05 mg / mL NHS, 10 mg / mL NaCl, and 5 mg / mL MES buffer (pH 5.6), and incubated at 37 °C for 24 hours, after the reaction, the samples were rinsed with deionized water and dried, and the treated sample was designated as the PDPA-Hep group.

[0224] (4) NO loading process:

[0225] The NO loading process used a high-pressure NO treatment method, the specific steps were as follows: the PDPA and PDPA-Hep samples were first immersed in a 0.3 mol / L sodium methoxide solution, and then placed in a custom stainless steel NO reactor; the reactor was flushed with 3 bar argon gas (5 minutes x 3 times, then 10 minutes x 2 times), to completely remove residual oxygen and moisture; then, 5 bar of pure NO gas was introduced into the reactor, and incubated under sealed conditions for 72 hours; after the reaction, the samples were again flushed with 6 bar argon gas (5 minutes x 2 times, 10 minutes x 2 times); after the samples were removed, they were thoroughly rinsed with anhydrous methanol and dried in a fume hood, and the obtained NO-loaded samples were designated as the PDPA@NO group and the PDPA@NO-Hep group, respectively.

[0226] Sample detection:

[0227] The samples prepared in Example 2 above were detected and analyzed, including: 316L SS group sample, PD group sample, PDPA group sample, PDPA-Hep group sample, PDPA@NO group sample and PDPA@NO-Hep group sample. One or more samples can be detected and analyzed as needed. The important indicators of coating function were detected: amino load, NO carrying capacity and heparin grafting amount:

[0228] (1) The amino load of the samples obtained in Example 2 above was detected, and the amino load statistical diagram shown in Figure 2 was obtained. According to Figure 2, it can be seen that: Figure 29 Figure 29

[0229] 1) PDPA group sample: The amino load of PDPA coating is relatively high, about 400 nmol / cm2, which proves the successful preparation of PDPA coating. The more abundant amino groups on the surface of PDPA can effectively increase the surface functionality.

[0230] 2) PDPA@NO group sample and PDPA-Hep group sample: After loading NO or heparin, the amino load changes. The amino load of PDPA@NO and PDPA-Hep coating decreases compared with pure PDPA coating, which indicates that the loading of NO and heparin is realized through amino groups, which may compete with amino groups for surface binding sites to some extent, or affect the loading of amino groups through chemical interaction.

[0231] 3) PDPA@NO-Hep group sample: The amino load decreases again, indicating that the loading of NO and heparin may further consume the grafting of amino groups of PDPA coating, indirectly proving the successful preparation of the coating. Further inhibition of amino grafting, this synergistic loading coating proves the successful preparation of the coating.

[0232] (2) The NO carrying capacity of the samples obtained in Example 2 above was detected, and the NO carrying capacity statistical diagram shown in Figure 3 was obtained. According to Figure 3, it can be seen that: Figure 30 Figure 30

[0233] 1) 316L SS group sample: The untreated 316 stainless steel hardly carries NO;

[0234] 2) PDPA@NO group sample: The NO loading coating significantly increases the NO carrying capacity, indicating that the NO loading is successful, and the NO carrying capacity significantly increases after two dopamine soaking;

[0235] (3) The surface heparin grafting amount of the samples obtained in Example 2 above was detected, and the heparin grafting amount statistical diagram shown in Figure 4 was obtained. According to Figure 4, it can be seen that: Figure 31 Figure 31 ​​​​​It can be seen that the PDPA-Hep group sample has a larger amount of heparin grafted on the surface compared to other samples.

[0236] Example 3

[0237] The samples in different states were prepared according to the following process:

[0238] (1) Pretreatment of 316L stainless steel substrate:

[0239] The 316 stainless steel substrate was mechanically polished using 1000 grit sandpaper. After polishing, the sample was ultrasonically cleaned in acetone, ethanol, and deionized water, respectively, for 15 minutes in each solution to remove surface contaminants and organic residues. The cleaned substrate was air-dried or dried with a nitrogen stream, ready for use. The cleaned 316L stainless steel substrate sample was referred to as the 316LSS group.

[0240] (2) Preparation of PDPA coating:

[0241] The polished 316L stainless steel substrate was placed face up in a 24-well plate and completely immersed in an aqueous solution containing 10 mg / mL dopamine and 8 mmol / L Tris. The sample was incubated at 37°C in the dark for 12 hours. After the reaction, the substrate was ultrasonically cleaned with deionized water to remove unbound residues and dried. The dried sample was referred to as the PD group.

[0242] After complete drying, the sample was immersed in an aqueous solution containing 5 mg / mL NaOH and 8 mg / mL PAH and incubated at 37°C in the dark for another 6 hours. Finally, the coating process was completed by drying again. The treated sample was referred to as the PDPA group.

[0243] (3) Heparin grafting process:

[0244] The PDPA-coated sample was immersed in an aqueous solution containing 7 mg / mL heparin (HEP), 9 mg / mL EDC, 2 mg / mL NHS, 100 mg / mL NaCl, and 918 mg / mL MES buffer (pH 5.6) and incubated at 37°C for 8 hours. After the reaction, the sample was rinsed with deionized water and dried. The treated sample was referred to as the PDPA-Hep group.

[0245] (4) NO loading process:

[0246] The NO loading process adopts a high-pressure NO treatment method. The specific steps are as follows: the PDPA and PDPA-Hep samples are respectively immersed in a 0.5 mol / L methoxy sodium solution, and then placed in a customized stainless steel NO reactor; the reactor is flushed with 13 bar argon gas (5 minutes each time for 3 times, and then 10 minutes for 2 times) to completely remove residual oxygen and moisture; then, 5 bar pure NO gas is introduced into the reactor, and incubated under sealed conditions for 72 hours; after the reaction, the reactor is again flushed with 6 bar argon gas (5 minutes for 2 times, and 10 minutes for 2 times); after the sample is taken out, it is washed with anhydrous methanol and dried in a fume hood, and the obtained NO-loaded samples are named as the PDPA@NO group and the PDPA@NO-Hep group.

[0247] Sample detection:

[0248] The samples prepared in the above embodiment 3 are detected and analyzed, wherein the samples include: the 316L SS group sample, the PD group sample, the PDPA group sample, the PDPA-Hep group sample, the PDPA@NO group sample, and the PDPA@NO-Hep group sample. One or more samples can be detected and analyzed as needed for each detection. The important indicators of the coating function are detected, including the amino group content, the NO carrying capacity, and the heparin grafting amount:

[0249] (1) The amino loading amount of the samples obtained in the above embodiment 3 is detected, and the amino loading amount statistical diagram shown in FIG. 2 is obtained. According to the diagram, it can be known that: Figure 32 Figure 32

[0250] 1) The PDPA group sample: the amino loading amount of the PDPA coating is relatively high, about 150 nmol / cm2, which proves the successful preparation of the PDPA coating. The rich amino groups of the PDPA can effectively load amino molecules and increase the surface functionality.

[0251] 2) The PDPA@NO group sample and the PDPA-Hep group sample: after loading NO or heparin, the amino loading amount changes. The amino loading amount of the PDPA@NO and PDPA-Hep coatings decreases compared with the pure PDPA coating, which indicates that the loading of NO and heparin is achieved through the amino group, which may compete with the amino group for the surface binding sites to some extent, or affect the loading of the amino group through chemical interaction.

[0252] 3) The PDPA@NO-Hep group sample: the amino loading amount decreases again, which indicates that the loading of NO and heparin may further consume the amino group grafting of the PDPA coating, indirectly proving the successful preparation of the coating. The further inhibition of the amino group grafting proves the successful preparation of the coating.

[0253] ​​(ii) The NO carrying capacity of the samples obtained in Example 3 above was detected, and the results are shown in the NO carrying capacity statistical chart in Figure 2, according to which it can be seen that: Figure 33 Figure 33

[0254] 1) 316L SS group sample: untreated 316 stainless steel carried almost no NO;

[0255] PD group sample: the PD group sample untreated with sodium hydroxide and PAH carried only a small amount of NO;

[0256] PDPA@NO group sample: the NO loading coating significantly increased the NO carrying capacity, indicating that the NO loading was successful, and the NO carrying capacity was significantly increased.

[0257] (iii) The heparin grafting amount of the samples obtained in Example 3 above was detected, and the results are shown in the heparin grafting amount statistical chart in Figure 3, according to which it can be seen that: Figure 34 Figure 34

[0258] PDPA-Hep group sample: the surface heparin grafting amount was significantly improved, and the heparin grafting amount was greatly increased.

[0259] The embodiments of the present application are described above in combination with the drawings, and the embodiments and features in the embodiments of the present application can be combined with each other without conflict, and the present application is not limited to the specific embodiments described above, which are only illustrative and not restrictive. Those skilled in the art can make many forms under the inspiration of the present application without departing from the scope of the present application and the protection scope of the claims, and all of them belong to the protection scope of the present application.​​​​

Claims

1. A needle, characterized in that, The needle is coated with an antibacterial and anticoagulant dual functional coating, and the preparation method of the dual functional coating comprises the following steps: S100, substrate material pretreatment: first, mechanically polish the substrate material, then clean and dry the substrate material, and then prepare it for use; S200, PDPA coating preparation: immerse the substrate material in an aqueous solution containing 0.1-100 mg / mL dopamine and 0.2-8 mmol / L Tris, incubate in the dark for 12-50 h, then clean and dry the substrate material; then immerse the substrate material in an aqueous solution containing 0.3-10 mg / mL NaOH and 0.2-8 mg / mL PAH, continue to incubate in the dark for 6-20 h, and then dry again to complete the preparation of the PDPA coating; S300, heparin grafting: immerse the substrate material loaded with the PDPA coating in an aqueous solution containing 0.2-7 mg / mL heparin, 0.1-9 mg / mL EDC, 0.05-2 mg / mL NHS, 10-100 mg / mL NaCl and 5-18 mg / mL MES buffer, incubate for 8-24 h, and then clean and dry the substrate material to obtain a substrate material loaded with PDPA-Hep; S400, NO loading: immerse the substrate material loaded with PDPA-Hep in a solution containing 0.01-0.5 mol / L sodium methoxide, then place it in a NO reactor, introduce 1-15 bar of NO gas into the NO reactor, and incubate under sealed conditions for 30-120 h, then clean and dry the substrate material again to obtain a PDPA@NO-Hep coating loaded on the substrate material; In step S400, before introducing the NO gas into the NO reactor, first flush the NO reactor with 1-15 bar of argon; after introducing the NO gas into the NO reactor for reaction, flush the substrate material again with 1-15 bar of argon.

2. The needle of claim 1 wherein, In step S100, the cleaning process of the substrate material comprises: immersing the substrate material in acetone for ultrasonic cleaning for 5-30 min; and / or, immerse the substrate material in ethanol for ultrasonic cleaning for 5-30 min; and / or, immerse the substrate material in deionized water for ultrasonic cleaning for 5-30 min.

3. The needle of claim 1 wherein, In step S200, the incubation temperature is 30-45℃, and deionized water is used for cleaning the substrate material.

4. The needle of claim 1 wherein, In step S300, the incubation temperature is 30-45℃, and deionized water is used for cleaning the substrate material.

5. The needle of claim 1 wherein, In step S400, after the substrate material loaded with the PDPA@NO-Hep coating is taken out, anhydrous methanol is used to clean the substrate material.

Images