Rare earth-based coating for extracorporeal circulation system tubing and method of making same

Abstract

The application provides a rare earth-based coating for extracorporeal circulation system pipeline and a preparation method thereof, and the preparation method comprises the following steps: step 1, immersing the pipeline in a pretreatment liquid, and after immersion, washing and drying are performed to obtain a pipeline with a dopamine transition layer; step 2, immersing the pipeline with the dopamine transition layer in a rare earth immersion liquid, and after immersion, washing and drying are performed to obtain the rare earth-based coating for extracorporeal circulation system pipeline. The rare earth-based coating for extracorporeal circulation system pipeline disclosed by the application forms a dense and stable rare earth ternary coating on the PVC pipeline through the alternating action of rare earth ions, hyaluronic acid and dopamine cations and anions, and since the force of the three is electrostatic force, the coating has the effects of firmness, stability and non-falling.

Description

Technical Field

[0001] This invention belongs to the field of anticoagulation, and in particular relates to a rare earth-based coating for tubing in extracorporeal circulation systems and its preparation method. Background Technology

[0002] Traditional interventional tubing and stent devices are prone to poor interfacial compatibility and limited functionality during long-term service, easily leading to coagulation, hyperplasia, and inflammatory reactions on the material surface, hindering rapid endothelial repair, and affecting the long-term stability and safety of the devices. While biomolecular fixation and surface coating modification can improve material biocompatibility, the application of rare earth ions to medical material surfaces presents challenges such as poor binding stability, difficulty in balancing biosafety and precise controlled release, and unclear mechanisms of action. Furthermore, technical bottlenecks exist, including high energy consumption for separation and purification, insufficient functional synergy of composite material systems, poor large-scale production and equipment compatibility, and a lack of industry standards. There is an urgent need to develop a safe and stable surface modification system with anticoagulant, anti-proliferative, anti-inflammatory, and endothelialization-promoting functions to address key technical issues such as functional mismatch, structural instability, and difficulties in clinical translation in existing surface modification technologies. Summary of the Invention

[0003] In view of this, the present invention aims to overcome the defects in the prior art and proposes a rare earth-based coating for extracorporeal circulation system pipelines and its preparation method.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] A method for preparing a rare earth-based coating for tubing in an extracorporeal circulation system includes the following steps:

[0006] Step 1 involves immersing the pipeline in a dopamine hydrochloride pretreatment solution, followed by washing and drying to obtain a pipeline with a dopamine transition layer.

[0007] Step 2 involves immersing the tubing with the dopamine transition layer in a rare earth impregnation solution, followed by washing and drying to obtain the rare earth-based coating for the extracorporeal circulation system tubing.

[0008] Furthermore, the dopamine hydrochloride pretreatment solution in step 1 is prepared by a method including the following steps: dissolving dopamine hydrochloride in Tris-HCl buffer, adding anhydrous ethanol, and mixing.

[0009] Furthermore, the concentration of dopamine hydrochloride in the preparation method of the dopamine hydrochloride pretreatment solution is 2-5 mg / mL; the amount of anhydrous ethanol added in the preparation method of the dopamine hydrochloride pretreatment solution is 1-3 v / v of Tris-HCl buffer; and the pH of Tris-HCl buffer in the preparation method of the dopamine hydrochloride pretreatment solution is 6-9.

[0010] Furthermore, the pipeline in step 1 is a PVC pipeline; the impregnation step in step 1 lasts for 30-50 hours at a temperature of 20-30°C.

[0011] Furthermore, the rare earth impregnation solution in step 2 is prepared by a method including the following steps: mixing solution A and solution B, adding a crosslinking agent, and mixing evenly to obtain the crosslinking agent.

[0012] Furthermore, the A solution comprises hyaluronic acid, acetylsalicylic acid, lanthanum nitrate hexahydrate, and deionized water in a mass ratio of 1:(8-12):(4-6):(40-60).

[0013] Furthermore, the B solution comprises N-hydroxysuccinimide (NHS), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC), and dimethyl sulfoxide (DMSO) in a mass ratio of 1:(1-3):(10-30).

[0014] Furthermore, the volume ratio of liquid A to liquid B is (3-5):1; the amount of crosslinking agent added is 0.1-0.3 w / v of the sum of liquid A and liquid B; and the crosslinking agent is genipin.

[0015] Furthermore, the soaking step in step 2 lasts for 12-18 hours at a temperature of 20-30°C.

[0016] A rare earth-based coating for extracorporeal circulation system tubing prepared using the aforementioned preparation method.

[0017] The formation mechanism of the rare earth-based coating for the extracorporeal circulation system tubing is based on a multi-level functionalization modification and a multi-mechanism synergistic anticoagulation strategy. In the initial stage, the PVC tubing is immersed in a pretreatment solution containing dopamine hydrochloride (Tris-HCl buffer, pH=8.5, supplemented with 1-3% anhydrous ethanol for dissolution). Under this weakly alkaline environment, dopamine monomers undergo oxidative self-polymerization, forming a polydopamine (PDA) active layer rich in catechol groups and amino groups on the tubing surface. This layer is firmly anchored to the PVC substrate through both covalent and hydrogen bonds, providing high-density active sites for subsequent deposition of rare earth composites. The core coating stage then begins: a two-component rare earth impregnation solution is prepared. In this process, acetylsalicylic acid, acting as an antiplatelet drug carrier, is uniformly dispersed within a hydrophilic three-dimensional network composed of hyaluronic acid. Through slow dissolution, it continuously inhibits platelet cyclooxygenase activity and blocks thromboxane A2 synthesis, effectively suppressing platelet activation and aggregation. Simultaneously, it acts as an inhibitor, aided by lanthanum ions. Genipin, as a natural cross-linking agent, precisely identifies free amino groups on the hyaluronic acid chain, generating a cross-linked bridging structure through a ring-opening reaction. This weaves linear hyaluronic acid molecules into a dense three-dimensional network, simultaneously achieving inhibition of rare earth ions (La). 3+ The embedding and fixation of hyaluronic acid and acetylsalicylic acid significantly improves the structural stability and anti-swelling ability of the coating. When the pipeline with the pre-coated PDA layer is immersed in the composite impregnation solution, the positively charged PDA surface captures the negatively charged hyaluronic acid-rare earth-drug complex through electrostatic adsorption. After 12-18 hours of low-temperature deposition (20-30℃), the cross-linking reaction initiated by genipin runs through the entire coating system, ultimately forming a multi-layered composite structure from the inside out, consisting of a PDA active transition layer, a hyaluronic acid / genipin cross-linking network layer, and a functional layer loaded with acetylsalicylic acid and lanthanum ions. In this structure, the carboxyl groups of hyaluronic acid generate electrostatic repulsion to prevent the adhesion of blood components, lanthanum ions act as calcium antagonists to interfere with the activation of coagulation factors, and acetylsalicylic acid exerts a pharmacological antiplatelet effect. These three, together with the physical barrier strengthened by genipin, constitute a multi-dimensional anticoagulation system. Furthermore, through the biocompatibility transition of the PDA layer and the endothelialization-promoting properties of hyaluronic acid, a balance between long-term anticoagulation and tissue affinity is achieved.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The rare earth-based coating for extracorporeal circulation system pipelines described in this invention forms a dense and stable rare earth ternary coating on PVC pipelines through the alternating action of rare earth ions, hyaluronic acid, and dopamine anions and cations. Since the interaction force among the three is an electrostatic force, the coating has the effect of being firm, stable, and non-detachable.

[0020] The hyaluronic acid in the rare earth-based coating for the extracorporeal circulation system tubing described in this invention is a natural polymer material with strong biocompatibility to the human body and plays a role in maintaining cell and structural integrity. In addition, the carboxyl functional groups contained in hyaluronic acid can resist platelet and red blood cell adhesion and exhibit an anticoagulant effect.

[0021] The rare earth elements in the rare earth-based coating of the extracorporeal circulation system tubing described in this invention act as calcium antagonists, which can synergistically improve the anticoagulation efficiency of the tubing, thereby giving the tubing a highly efficient anticoagulation effect. Attached Figure Description

[0022] Figure 1 This is a quantitative analysis chromatogram of amine groups as described in an embodiment of the present invention. Detailed Implementation

[0023] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0024] The reagents used in the various embodiments and comparative examples of this invention are as follows:

[0025] Hyaluronic acid, abbreviated as HA.

[0026] 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, hereinafter referred to as EDC.

[0027] 2-Morpholine ethanesulfonic acid, hereinafter referred to as MES.

[0028] Genipin, dopamine hydrochloride, hyaluronic acid, N-hydroxysuccinimide (NHS), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC), acetylsalicylic acid, and lanthanum nitrate hexahydrate were purchased from Maclean's Reagent Co., Ltd.

[0029] Ethanol, DMSO, sodium chloride, peptone, and yeast extract were purchased from Aladdin Reagent Co., Ltd.

[0030] All chemicals were used without further processing.

[0031] Distilled water (ρ=18.2 MΩ·cm, 25℃) comes from the Millipore milli-Q water purification system.

[0032] In addition, PBS buffer and physiological saline were purchased from Aladdin, and bovine blood was collected from fresh beef cattle at the slaughterhouse.

[0033] The present invention will be described in detail below with reference to the embodiments.

[0034] Example 1

[0035] A method for preparing a rare earth-based coating for tubing in an extracorporeal circulation system includes the following steps:

[0036] (1) Pretreatment of PVC pipes: Take sterilized scissors and cut the 1m long PVC pipe into multiple 8-10cm long PVC pipes. Soak them in a mixture of water and ethanol with a mass ratio of 1:2, ultrasonically wash for 30min, and then put them in an oven to dry at 50℃.

[0037] (2) Preparation of dopamine hydrochloride pretreatment solution: Take 400 mg of dopamine hydrochloride powder, add it to 100 mL of Tris-HCl buffer (pH= 8.5), stir it evenly with a clean glass rod at 25℃, add 1 mL of anhydrous ethanol to help dissolve it, so that the dopamine hydrochloride is completely dissolved, wrap it with kraft paper and sealing film, and set it aside for later use. This is the dopamine hydrochloride pretreatment solution.

[0038] (3) Preparation of rare earth impregnation solution: Solution A: Dissolve 10 mg hyaluronic acid, 90 mg acetylsalicylic acid, and 50 mg lanthanum nitrate hexahydrate in 500 mL of deionized water to form rare earth impregnation solution A; Solution B: Dissolve 10 mg NHS and 20 mg EDC in 100 mL of DMSO by stirring to form rare earth impregnation solution B; Mix 400 mL of solution A with 100 mL of solution B, add 0.8 mg genipin and stir until homogeneous.

[0039] (4) Preparation of rare earth-based coatings for extracorporeal circulation system pipelines:

[0040] Take the pretreated PVC pipe from step (1) and immerse it in the hydrochloric acid dopamine pretreatment solution in step (2) for 48 hours. The immersion temperature is controlled by a water bath at 25°C. After the immersion time is over, take out the pipe, wash it three times with pure water, and then transfer it to a vacuum oven to dry at 40°C. Then immerse it in the rare earth impregnation solution in step (3) for 16 hours. The immersion temperature is controlled by a water bath at 25°C. After the immersion time is over, take out the pipe, wash it three times with pure water, and then transfer it to a vacuum oven to dry. After drying, wrap it in a vacuum sealed bag for later use. This is the pipe with a rare earth base coating.

[0041] Comparative Example 1 (without rare earth elements)

[0042] The only difference from Example 1 is that solution A consists of 10 mg of hyaluronic acid, 90 mg of acetylsalicylic acid, and 500 mL of deionized water.

[0043] Comparative Example 2 (Reduced Amount of Acetylsalicylic Acid)

[0044] The only difference from Example 1 is that Solution A consists of 10 mg of hyaluronic acid, 10 mg of acetylsalicylic acid, 50 mg of lanthanum nitrate hexahydrate, and 500 mL of deionized water.

[0045] Comparative Example 3 (without solution A)

[0046] The only difference from Example 1 is that: Step (3) Preparation of rare earth impregnation solution: Solution B: Take 10mg NHS and 20mg EDC and 100mL DMSO and stir to dissolve to form rare earth impregnation solution B; Take 500mL of solution B, add 0.8mg genipin and stir evenly to obtain the solution.

[0047] Comparative Example 4 (without solution B)

[0048] The only difference from Example 1 is: Step (3) Preparation of rare earth impregnation solution: Solution A: Take 10mg of hyaluronic acid, 90mg of acetylsalicylic acid, 50mg of lanthanum nitrate hexahydrate and 500mL of deionized water to dissolve and form rare earth impregnation solution A; Take 500mL of solution A and add 0.8mg of genipin and stir evenly to obtain the solution.

[0049] Comparative Example 5 (without genipin)

[0050] The only difference from Example 1 is that: Step (3) Preparation of rare earth impregnation solution: Solution A: Take 10mg hyaluronic acid, 90mg acetylsalicylic acid, 50mg lanthanum nitrate hexahydrate and dissolve in 500mL deionized water to form rare earth impregnation solution A; Solution B: Take 10mg NHS and 20mg EDC and stir to dissolve in 100mL DMSO to form rare earth impregnation solution B; Take 400mL of solution A and 100mL of solution B and mix them, stirring until uniform.

[0051] Experimental Example 1: Coagulation Parameter Test

[0052] Cut to 8cm 2 Sample tubes were placed in 24-well plates and soaked in physiological saline for 1 hour. Fresh bovine blood was collected and centrifuged at 4000 rpm for 10 minutes to obtain anemic platelet plasma. The activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) of the three coagulation parameters were measured at this time. The physiological saline in the 24-well plates was removed, and then 700 μL of anemic platelet plasma was added. The plates were incubated in a 37°C water bath for 1 hour, and the coagulation parameters were measured after incubation.

[0053] The results are shown in Table 1. There was no difference in PT results between the rare earth-based extracorporeal circulation system tubing coating and the blank group. However, the APTT and TT coagulation times of the rare earth-based extracorporeal circulation system tubing coating were better, with APTT > 200s, which proves that the rare earth-based extracorporeal circulation system tubing coating has a strong anticoagulant effect.

[0054] Table 1 Coagulation Data

[0055]

[0056] Experiment Example 2: Plasma Recalcification Experiment:

[0057] Take 5cm 2 The test tubes were equilibrated with PBS for 2 hours. Then, 0.2 mL of anemic platelet plasma from Experiment 1 was added to each tube. The tubes were incubated at 37°C for 5 minutes, followed by 0.2 mL of 25 mM calcium chloride solution preheated at 37°C. Timing was started immediately, and the time was stopped when plasma coagulation or white turbidity appeared. The time recorded on the timer was the plasma recalcification time. As shown in Table 2, Example 1, using the complete formulation (containing dopamine hydrochloride pretreatment layer, lanthanum nitrate hexahydrate / hyaluronic acid / acetylsalicylic acid solution A, NHS / EDC activation solution B, and genipin crosslinking), showed a significantly prolonged recalcification time (24.2 min), nearly four times longer than the control group (5.5 min), and superior to all comparative examples. Comparative Example 1 (without rare earth elements) only took 6.1 min, confirming that La... 3+ Through competitive adsorption of Ca 2+ The coating exhibits a core anticoagulant effect. The recalcification time increased sequentially in Comparative Examples 2 (reduced acetylsalicylic acid), 3 (without solution A), 4 (without solution B), and 5 (without genipin), indicating that the dopamine transition layer, the synergistic effect of acetylsalicylic acid, NHS / EDC chemical cross-linking, and dynamic covalent bonding of genipin are crucial for coating stability and anticoagulant durability. This coating achieves highly efficient anticoagulant action through a triple mechanism of physical barrier, ion antagonism, and biochemical regulation, providing a novel anticoagulant strategy for extracorporeal circulation devices that does not require heparin.

[0058] Table 2 Plasma recalcification time

[0059]

[0060] Experimental Example 3: Quantitative Analysis of Surface Amine Groups

[0061] The experimental procedure for quantifying amino groups using the Acid Orange II (AOII) staining method can be optimized as follows: Place the sample in a 24-well plate, add 200 μL of AOII hydrochloric acid solution with a concentration of 1.75 mg / mL and a pH ≈ 4, and react at 37°C for 8 hours to allow sufficient amino group binding. Then, remove the supernatant, wash the sample surface three times with hydrochloric acid solution at pH 4, and dry. Next, add 170 μL of 0.4 mg / mL NaOH solution to the dried sample surface, and let it stand at room temperature for 30 minutes to elute the bound AOII dye. Transfer the eluent to a 96-well plate. Simultaneously, prepare a series of AOII standard solutions using NaOH solution of the same concentration. Measure the absorbance of all samples and standard solutions at 485 nm using a microplate reader, and calculate the amino functional group density per unit area of ​​the sample surface based on the standard curve. Figure 1 It can be seen that the number of amine groups in the coating decreases after the combination of rare earth ions, indicating that rare earth ions can form stable coordination bonds with amine groups. In addition, without solution A or solution B, the concentration of amine groups in the coating decreases significantly, which is not conducive to the formation of a stable coordination structure between rare earth ions and the coating substrate.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a rare earth-based coating for tubing in an extracorporeal circulation system, characterized in that: Includes the following steps: Step 1 involves immersing the pipeline in a dopamine hydrochloride pretreatment solution, followed by washing and drying to obtain a pipeline with a dopamine transition layer. Step 2 involves immersing the tubing with the dopamine transition layer in a rare earth impregnation solution, followed by washing and drying to obtain the rare earth-based coating for the extracorporeal circulation system tubing. The rare earth impregnation solution in step 2 is prepared by a method including the following steps: mixing liquid A and liquid B, adding a crosslinking agent, and mixing evenly to obtain the rare earth impregnation solution. Solution A comprises hyaluronic acid, acetylsalicylic acid, lanthanum nitrate hexahydrate, and deionized water in a mass ratio of 1:(8-12):(4-6):(40-60). The B solution comprises N-hydroxysuccinimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and dimethyl sulfoxide in a mass ratio of 1:(1-3):(10-30). The volume ratio of liquid A to liquid B is (3-5):

1.

2. The method for preparing a rare earth-based coating for extracorporeal circulation system tubing according to claim 1, characterized in that: The dopamine hydrochloride pretreatment solution in step 1 is prepared by a method including the following steps: dissolving dopamine hydrochloride in Tris-HCl buffer, adding anhydrous ethanol, and mixing.

3. The method for preparing a rare earth-based coating for extracorporeal circulation system tubing according to claim 2, characterized in that: The concentration of dopamine hydrochloride in the preparation method of the dopamine hydrochloride pretreatment solution is 2-5 mg / mL; the amount of anhydrous ethanol added in the preparation method of the dopamine hydrochloride pretreatment solution is 1-3 v / v of Tris-HCl buffer; the pH value of Tris-HCl buffer in the preparation method of the dopamine hydrochloride pretreatment solution is 6-9.

4. The method for preparing a rare earth-based coating for extracorporeal circulation system tubing according to claim 1, characterized in that: The pipeline in step 1 is a PVC pipeline; the impregnation time in step 1 is 30-50 hours and the temperature is 20-30℃.

5. The method for preparing a rare earth-based coating for extracorporeal circulation system tubing according to claim 1, characterized in that: The amount of crosslinking agent added is 0.1-0.3 w / v of the sum of liquid A and liquid B; the crosslinking agent is genipin.

6. The method for preparing a rare earth-based coating for extracorporeal circulation system tubing according to claim 1, characterized in that: The soaking step in step 2 lasts for 12-18 hours at a temperature of 20-30°C.

7. A rare earth-based coating for extracorporeal circulation system tubing prepared by the preparation method according to any one of claims 1-6.

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