A gradient cross-linking preparation method of a high-selectivity blood low-density lipoprotein adsorption resin

Abstract

The application discloses a gradient crosslinking preparation method of a high-selectivity blood low-density lipoprotein adsorption resin, and the adsorption resin is in a granular form, has a gradient crosslinking structure with gradually reduced crosslinking degrees from the outside to the inside in the radial direction, and forms a multistage pore structure of a large hole-mesopore-micropore inside; a lipoprotein recognition ligand is fixed on the resin particles, and an anti-protein contamination layer is arranged on the outer surface; during preparation, porous polymer microspheres are prepared through suspension polymerization, the diffusion process of a crosslinking agent from the outside to the inside is controlled to form the gradient crosslinking, then functional groups are introduced, the ligand is fixed, and surface modification is performed. Through the partition design of the outer anti-contamination layer, the middle layer recognition and the inner layer mass transfer, and the synergistic effect of the gradient crosslinking and the multistage pore structure, the selective adsorption capacity of the resin for low-density lipoprotein is significantly improved, non-specific protein adsorption is reduced, and the resin has good blood compatibility and regeneration stability.

Description

Technical Field

[0001] This invention belongs to the field of resin preparation technology for blood substance separation and adsorption, specifically involving a gradient crosslinking preparation method for a highly selective blood low-density lipoprotein adsorption resin. Background Technology

[0002] Abnormally elevated levels of low-density lipoprotein (LDL) are closely related to the development and progression of cardiovascular diseases such as atherosclerosis. Therefore, the selective removal of LDL from blood or plasma has become an important research direction in the field of blood purification. In existing technologies, LDL adsorbents mainly achieve the enrichment and removal of LDL through electrostatic interactions, affinity interactions, hydrophobic interactions, or combinations thereof. Their carrier forms mainly include resin particles, microspheres, membrane materials, and powdered adsorbents.

[0003] Among them, microsphere and resin particle adsorbents have become the most widely used technical routes in the field of blood adsorption due to their advantages such as large specific surface area, good flowability, and ease of functionalization. Existing LDL adsorption resins mostly use cellulose, agarose, polystyrene, and polyvinyl alcohol as matrices, and achieve LDL adsorption by introducing dextran sulfate, heparin, or negatively charged functional groups. However, these adsorbents mainly rely on electrostatic interactions or simple affinity interactions to achieve LDL binding, which still has significant limitations in complex blood systems.

[0004] First, from the perspective of adsorption mechanism, since the apolipoproteins on the surface of LDL have certain similarities in charge and structure with various plasma proteins, existing adsorbents based on anionic ligands often adsorb high-abundance proteins such as albumin, immunoglobulins and fibrinogen simultaneously in practical applications, resulting in insufficient adsorption selectivity and a decrease in effective adsorption capacity.

[0005] Secondly, from the perspective of material structure, most existing resin particles adopt a uniform cross-linked structure. Their internal pore distribution lacks a fine design for LDL molecular size and plasma mass transfer characteristics, which restricts the diffusion of LDL inside the particles. The adsorption process is mainly concentrated in the particle surface area, resulting in low utilization of internal adsorption sites and affecting the overall adsorption efficiency and kinetic performance.

[0006] Secondly, from the perspective of surface properties, some adsorbent materials are prone to non-specific protein adsorption in a blood environment, forming a protein contamination layer on the particle surface. This not only further reduces the accessibility of adsorption sites but may also affect blood compatibility and safety of use. In addition, during repeated regeneration and use, some functional ligands may detach or become inactive, leading to a gradual decline in adsorption performance.

[0007] Furthermore, compared to resin granular materials, hollow fiber membranes and flat sheet membranes, while possessing the advantage of high structural integration, generally suffer from challenges such as difficulty in functionalization modification, limited adsorption efficiency, and easy pore blockage, thus restricting their application in the field of highly selective LDL adsorption. Although powdered adsorbents exhibit high adsorption rates, their use in blood systems presents challenges such as separation difficulties and coagulation risks, making them unsuitable for long-term clinical applications.

[0008] In summary, existing LDL adsorbent materials still generally suffer from problems such as insufficient adsorption selectivity, strong non-specific protein adsorption, low internal mass transfer efficiency, low utilization of adsorption sites, and limited regeneration stability.

[0009] Therefore, there is an urgent need in this field to develop an adsorbent material with more optimized structural design and functional distribution to improve the selective adsorption capacity of LDL, while taking into account mass transfer efficiency, blood compatibility and stability in use.

[0010] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0011] To address the problems existing in the prior art, the present invention aims to provide a gradient crosslinking preparation method for a highly selective blood low-density lipoprotein adsorption resin. By constructing a gradient crosslinking structure with gradually changing crosslinking degree from the outside to the inside inside the resin particles, and combining it with hierarchical pore structure design and ligand distribution control, the method can improve the diffusion efficiency of LDL inside the particles and the utilization rate of adsorption sites while ensuring the mechanical strength of the material, reduce the adsorption of non-specific proteins, and achieve efficient and selective removal of low-density lipoprotein in the blood.

[0012] To achieve the above objectives, the present invention adopts the following technical solution:

[0013] A highly selective blood low-density lipoprotein adsorption resin, wherein the adsorption resin is composed of granular resin, and the degree of cross-linking of the resin particles decreases radially from the outside to the inside, wherein the degree of cross-linking of the outer layer, the middle layer and the core falls into the corresponding range respectively.

[0014] The resin particles form a multi-level porous structure consisting of macropores, mesopores, and micropores.

[0015] The resin particles are immobilized with lipoprotein recognition ligands.

[0016] Preferably, the pore size of macropores is 50–200 nm; the pore size of mesopores is 20–50 nm; and the pore size of micropores is less than 10 nm.

[0017] The above-mentioned technical solution includes a hierarchical pore structure comprising macropores, mesopores, and micropores. Macropores are used to form channels for blood or plasma to enter, mesopores are used to provide channels for low-density lipoprotein mass transfer and binding, and micropores are used to increase surface area and provide attachment sites. Through this hierarchical pore size setting, it can be combined with a gradient cross-linking structure to form a hierarchical mass transfer network inside the particle.

[0018] Preferably, the resin matrix is ​​selected from one of styrene-divinylbenzene copolymer, polyvinyl alcohol or its modified materials, cellulose and its modified products, agarose and its modified products, or chitosan and its modified products.

[0019] Preferably, a ligand is immobilized in the intermediate layer or pores of the resin particles, and the ligand is a polypeptide with apolipoprotein recognition capability; the polypeptide is a lysine-glycine-lysine tripeptide.

[0020] Preferably, the outer surface of the resin particles is provided with an anti-protein contamination layer, which is selected from polyethylene glycol, zwitterionic polymers or hydrophilic polymers.

[0021] Specifically, the material of the protein contamination layer is one of polyethylene glycol, polysulfobetaine methacrylate, polycarboxybetaine methacrylate, or polyvinylpyrrolidone.

[0022] By adopting the above technical solution, different functional components are organized in a radial partitioning manner. The lipoprotein recognition ligand is preferably fixed in the middle layer or the inner wall of the pores of the resin particles, and the anti-protein contamination graft layer is preferably disposed on the outermost surface of the resin particles. When arranged in this way, the two form a layered distribution in space: the outer layer mainly undertakes the anti-protein contamination function, while the middle layer and the inner wall of the pores undertake the lipoprotein recognition function, thereby avoiding the high-density coexistence of the two on the same surface, which would cause coverage, compression or site occlusion.

[0023] The lipoprotein recognition ligand is preferably covalently fixed by epoxy groups pre-introduced on the resin surface or the inner wall of the pores; the anti-protein contamination graft layer is preferably fixed by surface-initiated graft polymerization or by the reaction of terminal functional groups with surface epoxy groups.

[0024] Therefore, the base layer and the antifouling layer are relatively independent in terms of fixed sequence and spatial position. There will be no obvious competition or squeezing between the two, nor will the functional sites affect each other due to their coexistence in the same layer.

[0025] Preferably, the specific surface area of ​​the resin particles is 100–600 m². 2 / g, with a particle size of 50–300μm.

[0026] A gradient crosslinking preparation method for a highly selective blood low-density lipoprotein adsorption resin includes the following steps:

[0027] 1) Porous polymer microspheres were prepared by suspension polymerization;

[0028] 2) The microspheres are brought into contact with a crosslinking agent, and the diffusion process of the crosslinking agent from the outside to the inside is controlled to make the microspheres form a gradient crosslinking structure with the degree of crosslinking gradually decreasing from the outside to the inside;

[0029] 3) The resin is subjected to a functional group introduction treatment;

[0030] 4) Immobilize functional ligands onto resin particles;

[0031] 5) Modify the surface of the resin particles;

[0032] 6) After preparation, the resin particles are washed sequentially with ethanol, deionized water and buffer solution to remove residual monomers, crosslinking agents and porogens until no obvious organic residues are detected in the eluent; then the resin particles are dried and stabilized for later use.

[0033] The above technical solution involves first preparing porous polymer microspheres through suspension polymerization. Then, while the resin microspheres are in a swollen state, the crosslinking agent diffuses from the external system into the interior of the microspheres. The outer layer comes into contact with the high concentration of crosslinking agent first, resulting in more crosslinking. The middle layer comes into contact later, with a moderate degree of crosslinking. The core comes into contact last, and the amount of crosslinking agent reaching it is limited, so the crosslinking is the lowest. The reaction is terminated at an appropriate time point, thus forming a crosslinking gradient range.

[0034] Functional groups are then introduced, and the peptides are immobilized in the intermediate layer or on the inner wall of the pores. Finally, an anti-protein contamination graft layer is constructed on the outermost layer of the resin particles. By setting the order described above, the functional ligands and the anti-contamination layer can be located in different radial regions, avoiding site obstruction or performance interference caused by overlapping fixation sequences.

[0035] Preferably, the functional group is an epoxy group or a carboxyl group, and the functional group is preferably an epoxy group;

[0036] By adopting the above technical solution, the epoxy group, as a reactive functional group, can undergo a ring-opening reaction with the amino group in the lysine-glycine-lysine tripeptide, thereby achieving covalent fixation of the ligand.

[0037] In this pathway, ligand fixation preferably occurs in the middle layer or inner wall of the pores of the resin particles to ensure that they are located in a position that is conducive to lipoprotein contact. At the same time, an anti-protein contamination graft layer is introduced on the outer surface, thereby forming a division of labor structure of "outer layer anti-contamination and inner layer recognition".

[0038] Preferably, the porogen used in suspension polymerization includes one or more of toluene, n-hexane, cyclohexane, and isooctane.

[0039] By introducing porogens, initial pore structures can be formed during polymerization, providing mass transfer channels and a spatial basis for subsequent crosslinking gradient formation and ligand fixation.

[0040] Preferably, the gradient crosslinking is as follows:

[0041] The degree of cross-linking of the outer layer is 30%–50%;

[0042] The cross-linking degree of the intermediate layer is 15%–30%;

[0043] The degree of cross-linking in the core is 5% to 15%.

[0044] Preferably, in step 2), the diffusion rate of the crosslinking agent is adjusted by controlling the concentration of the crosslinking agent, the reaction time, or the solvent system to form the gradient crosslinking structure.

[0045] Preferably, in step 2), the mass fraction of the crosslinking agent is 5% to 30%; the swelling time is 10 to 60 min; the crosslinking reaction time is 0.5 to 6 h; and the reaction temperature is 40 to 80 °C.

[0046] By adopting the above technical solution, the microspheres are placed in a solvent system containing a crosslinking agent, so that the microspheres undergo a crosslinking reaction in a swollen state. By controlling the concentration of the crosslinking agent, the swelling time, the reaction time, and the reaction temperature, the crosslinking agent diffuses from the outside to the inside and forms a gradient distribution with decreasing crosslinking degree in the radial direction.

[0047] Preferably, the crosslinking agent includes at least one of divinylbenzene, N,N'-methylenebisacrylamide, and glutaraldehyde.

[0048] This invention constructs a gradient cross-linked structure in the radial direction of particles, combined with a hierarchical porous structure, directional ligand immobilization, and outer layer anti-protein contamination modification, enabling different functional components to be spatially partitioned, thereby forming a structural organization mode of outer layer shielding, middle layer recognition, and inner layer mass transfer, which has the following beneficial effects:

[0049] 1) Construct an anti-protein contamination graft layer on the outer surface of resin particles, and preferably fix lipoprotein recognition ligands to the middle layer or inner wall of the pores of the resin particles. When the resin particles come into contact with blood or plasma, the outer layer preferentially forms a low adsorption interface with non-target proteins, thereby reducing the non-specific adsorption of albumin, immunoglobulins and other high-abundance plasma proteins on the resin surface, reducing the probability of protein contamination layer formation, and maintaining the accessibility of adsorption sites.

[0050] 2) By constructing a gradient cross-linking structure with gradually decreasing cross-linking degree from the outside to the inside inside the resin particles, and combining it with a hierarchical pore structure of macropore-mesopore-micropore and lipoprotein recognition ligands enriched in the intermediate layer, low-density lipoprotein can preferentially bind in the effective recognition area after entering the particle; at the same time, the outer anti-protein contamination layer forms a certain shielding effect against non-target proteins, thereby improving the selective adsorption capacity of low-density lipoprotein and reducing the mis-adsorption of other plasma components.

[0051] 3) The synergistic design of hierarchical pore structure and gradient cross-linking structure forms a hierarchical mass transfer channel from macropores to mesopores to micropores inside the resin particles, which is conducive to the entry of blood or plasma components and the diffusion and binding of low-density lipoprotein, making fuller use of the adsorption sites inside the particles.

[0052] 4) The gradient cross-linking structure gives the outer layer of the resin particles a high degree of cross-linking and the core a low degree of cross-linking. This ensures the overall strength of the particles while maintaining the openness of the internal space, which is beneficial for the resin to maintain structural stability during blood purification and improve its tolerance to repeated use.

[0053] 5) After preparation, the resin particles are thoroughly washed to remove residual monomers, crosslinking agents and pore-forming agents, reduce leaching impurities, and thus improve the safety and applicability of the resin material when used in blood or plasma systems. Attached Figure Description

[0054] Figure 1 This is a schematic diagram illustrating the average removal rate of non-target proteins.

[0055] Figure 2 Image of adsorbent resin particles;

[0056] Figure 3 The graph shows the stability retention rate of the resin recycling experiments in Examples 1-3 and Comparative Example 1.3.5. Detailed Implementation

[0057] The present invention will be further described below through specific embodiments. To make the inventive objectives, technical solutions, and beneficial technical effects of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the embodiments described in this specification are merely for explaining the present invention and are not intended to limit the present invention.

[0058] Unless otherwise stated, all instruments and reagents used in the examples are commercially available or synthesized using conventional methods and can be used directly without further processing, and all instruments used in the examples are commercially available.

[0059] Reagents and instruments:

[0060] Functional group content: measured using a Thermo Fisher Infrared Spectrometer;

[0061] Average pore size and specific surface area: measured using a BET pore size and specific surface area analyzer.

[0062] Example 1:

[0063] Prepared by the following steps:

[0064] 1) Using styrene-divinylbenzene as monomer, suspension polymerization was carried out in the aqueous phase, and toluene and n-hexane (volume ratio 1:1) were added as pore-forming agents to prepare porous polymer microspheres;

[0065] 2) The obtained microspheres were placed in a crosslinking system containing divinylbenzene, with a crosslinking agent mass fraction of 20%, a swelling time of 30 min, and a reaction at 60 °C for 3 h, so that the crosslinking agent diffused from the outside to the inside to form a gradient crosslinking structure;

[0066] 3) Epichlorohydrin is used to treat the resin, introducing epoxy groups on the resin surface and the inner wall of the pores;

[0067] 4) Add the lysine-glycine-lysine tripeptide solution to the system and react under alkaline conditions to fix the polypeptide to the middle layer and inner wall of the resin particles through the ring-opening reaction of amino and epoxy groups.

[0068] 5) Initiate the graft polymerization of sulfobetaine methacrylate monomer on the outer surface of resin particles to form a protein-resistant graft layer;

[0069] 6) Wash the resin particles sequentially with ethanol, deionized water and phosphate buffer until there is no obvious organic residue in the eluent. Dry the resin particles and set aside for later use.

[0070] The parameters of the obtained resin particles are as follows:

[0071]

[0072] Example 2:

[0073] Resin particles are prepared using the following steps:

[0074] 1) The pore-forming agent used is toluene:cyclohexane = 1:1;

[0075] 2) Crosslinking agent mass fraction 25%, swelling time 40 min, reaction temperature 70℃, reaction time 4 h;

[0076] The remaining steps are the same as in Example 1.

[0077] The parameters of the obtained resin particles are as follows:

[0078]

[0079] Example 3:

[0080] Resin particles are prepared using the following steps:

[0081] 1) Polyvinyl alcohol microspheres are used as the matrix, and n-hexane and isooctane are used as pore-forming agents;

[0082] 2) Glutaraldehyde was selected as the crosslinking agent, with a mass fraction of 10%, a swelling time of 20 min, and a reaction time of 50℃ for 2 h;

[0083] The remaining steps are the same as in Example 1.

[0084] The parameters of the obtained resin particles are as follows:

[0085]

[0086] Example 4:

[0087] Resin particles are prepared using the following steps:

[0088] 1) Agarose-modified microspheres were used as the matrix, and cyclohexane was used as the pore-forming agent;

[0089] 2) The crosslinking agent used is N,N'-methylenebisacrylamide, with a mass fraction of 15%, a swelling time of 25 min, and a reaction temperature of 60℃ for 2.5 h;

[0090] The remaining steps are the same as in Example 1.

[0091] The parameters of the obtained resin particles are as follows:

[0092]

[0093] Example 5:

[0094] Resin particles are prepared using the following steps:

[0095] 1) Chitosan-modified microspheres were used, with toluene and isooctane as pore-forming agents;

[0096] 2) Glutaraldehyde was selected as the crosslinking agent, with a mass fraction of 8%, a swelling time of 15 min, and a reaction temperature of 40℃ for 1 h.

[0097] The remaining steps are the same as in Example 1.

[0098] The parameters of the obtained resin particles are as follows:

[0099]

[0100] Example 6:

[0101] Resin particles are prepared using the following steps:

[0102] 1) Using styrene-divinylbenzene as the matrix, suspension polymerization was carried out in the aqueous phase, with toluene and n-hexane as pore-forming agents, to obtain porous polymer microspheres with a particle size of 50 μm;

[0103] 2) The microspheres are contacted with divinylbenzene, the mass fraction of the crosslinking agent is 5%, the swelling time is 10 min, and the reaction is carried out at 40℃ for 0.5 h to form a gradient crosslinking structure with the degree of crosslinking gradually decreasing from the outside to the inside;

[0104] 3) The resin is treated with epoxy group introduction;

[0105] 4) The lysine-glycine-lysine tripeptide is fixed in the middle layer of the resin particles or on the inner wall of the pores;

[0106] 5) A polysulfobetaine methacrylate graft layer is formed on the outer surface of the resin particles by graft polymerization initiated by the corresponding monomers on the outer surface of the resin.

[0107] 6) Wash with ethanol, deionized water and buffer solution in sequence, and dry for later use.

[0108] The parameters of the obtained resin particles are as follows:

[0109] Particle size 50μm; specific surface area 100m² / g; macropores 50nm; mesopores 20nm; micropores less than 10nm; outer layer crosslinking degree 30%; middle layer crosslinking degree 15%; core crosslinking degree 5%; epoxy ligand content 0.3mmol / g.

[0110] Example 7:

[0111] Resin particles are prepared using the following steps:

[0112] 1) Using styrene-divinylbenzene as the matrix and toluene and cyclohexane as pore-forming agents, porous polymer microspheres with a particle size of 150 μm were prepared.

[0113] 2) The microspheres were contacted with divinylbenzene, the crosslinking agent mass fraction was 15%, the swelling time was 30 min, and the reaction was carried out at 60℃ for 3 h;

[0114] 3) The resin is treated with epoxy group introduction;

[0115] 4) The lysine-glycine-lysine tripeptide is fixed in the middle layer of the resin particles or on the inner wall of the pores;

[0116] 5) A polyvinylpyrrolidone graft layer is formed on the outer surface of the resin particles;

[0117] 6) Wash with ethanol, deionized water and buffer solution in sequence, and dry for later use.

[0118] The obtained resin particles have the following parameters: particle size 150 μm; specific surface area 350 m² / g; macropores 120 nm; mesopores 35 nm; micropores less than 10 nm; outer layer crosslinking degree 40%; middle layer crosslinking degree 22%; core crosslinking degree 10%; and epoxy ligand content 0.8 mmol / g.

[0119] Example 8:

[0120] Resin particles are prepared using the following steps:

[0121] 1) Using polyvinyl alcohol modified material as matrix and cyclohexane and isooctane as pore-forming agents, porous polymer microspheres with a particle size of 300 μm were prepared.

[0122] 2) The microspheres are contacted with glutaraldehyde, the mass fraction of the crosslinking agent is 30%, the swelling time is 60 min, and the reaction is carried out at 80℃ for 6 h to form a gradient crosslinking structure with the degree of crosslinking gradually decreasing from the outside to the inside;

[0123] 3) The resin is further converted into epoxy groups after undergoing carboxyl group introduction treatment;

[0124] 4) The lysine-glycine-lysine tripeptide is fixed in the middle layer of the resin particles or on the inner wall of the pores;

[0125] 5) A polycarboxylated betaine methacrylate graft layer is formed on the outer surface of the resin particles;

[0126] 6) Wash with ethanol, deionized water and buffer solution in sequence, and dry for later use.

[0127] The obtained resin particles have the following parameters: particle size 300 μm; specific surface area 600 m² / g; macropores 200 nm; mesopores 50 nm; micropores less than 10 nm; outer layer crosslinking degree 50%; middle layer crosslinking degree 30%; core crosslinking degree 15%; epoxy ligand content 1.2 mmol / g.

[0128] Comparative Example 1: Uniform crosslinking, no gradient

[0129] The matrix, pore structure, ligand, and antifouling layer are all retained, but the degree of crosslinking is not radially gradient.

[0130] Comparative Example 2: Gradient crosslinking, no ligand

[0131] It retains gradient crosslinking and hierarchical pores without introducing KGK tripeptide.

[0132] Comparative Example 3: With ligand, without outer antifouling layer

[0133] It retains gradient cross-linking and KGK tripeptide, but does not form an outer anti-protein contamination layer.

[0134] Comparative Example 4: With an outer antifouling layer, without a ligand

[0135] It retains the gradient crosslinking and antifouling layer, without introducing KGK tripeptide.

[0136] Comparative Example 5: Traditional DS / Heparin-based Adsorption Resin

[0137] The following tests were conducted on preferred embodiments 1-5 and comparative embodiments 1-5:

[0138] I. Dynamic column adsorption experiment, the results are shown in Table 1 below:

[0139]

[0140] II. Blood compatibility tests (hemolysis rate, platelet adhesion / activation, clotting time (e.g., APTT, PT, TT), complement activation (C3a, C5a)), results are shown in Table 2 below:

[0141]

[0142] III. Cyclic regeneration experiment to verify stability; results are attached. Figure 3 ;

[0143] IV. Non-specific adsorption (single-protein system, measuring the adsorption amounts of Alb, IgG, and Fbg separately; mixed system: under the coexistence of LDL / HDL / Alb / IgG / Fbg, observing the removal rate or adsorption amount of Alb, IgG, and Fbg individually), see Table 3 below:

[0144] Table 3 Adsorption capacity of single-component proteins (37℃, 60min)

[0145]

[0146] Note: Based on Table 3-5, a correlation diagram of the average removal rate of non-target proteins was plotted. Figure 1 (Non-specific adsorption index (%) = (Alb + IgG + Fbg) / 3.

[0147] V. Selectivity Experiment (Low-density lipoprotein (LDL), high-density lipoprotein (HDL), albumin (Alb), immunoglobulin (IgG), and fibrinogen (Fbg) were mixed in a certain proportion to construct a simulated plasma system; the adsorption resin was added to the system, and after shaking adsorption at 37°C for a certain period of time, the concentration changes of each component before and after adsorption were detected, and the removal rate of each component was calculated; the ratio of LDL removal rate to HDL removal rate was used as the selectivity index (SI1) to evaluate the selective adsorption capacity of the adsorption resin for LDL), the results are shown in Table 4 below:

[0148] Table 4. Removal rate of mixed protein system (37℃, 60min)

[0149]

[0150] SI1 = LDL removal rate / HDL removal rate; SI2 = LDL removal rate / (average removal rate of Alb + IgG + Fbg). Results are shown in Table 5. Selectivity index calculation:

[0151]

[0152] The table above illustrates that, compared to the comparative example, the embodiments of the present invention exhibit higher adsorption capacity for LDL in single-component adsorption experiments, while showing lower adsorption amounts for non-target proteins such as albumin, immunoglobulins, and fibrinogen. In the multi-component competitive adsorption system, the LDL removal rate of the embodiments is significantly higher than that of the comparative example, while the removal rates of HDL and other non-target proteins are significantly reduced, thus demonstrating a higher selectivity index. Among them, Example 2, with its gradient cross-linked structure, specific peptide ligands, and outer anti-protein contamination graft layer, exhibits the best performance, with its selectivity indices (SI1 and SI2) being significantly higher than those of the comparative example. This indicates that the present invention effectively improves the selective adsorption capacity for low-density lipoprotein and reduces the adsorption of non-specific proteins through structural synergistic design.

[0153] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A highly selective blood low-density lipoprotein adsorption resin, characterized in that, The adsorbent resin is composed of granular resin, and the resin particles have a gradient cross-linking structure with a gradually decreasing degree of cross-linking from the surface to the core in the radial direction. The resin particles form a multi-level porous structure consisting of macropores, mesopores, and micropores. The resin particles are immobilized with lipoprotein recognition ligands.

2. The highly selective blood low-density lipoprotein adsorption resin according to claim 1, characterized in that, The pore size of macropores is 50–200 nm; the pore size of mesopores is 20–50 nm; and the pore size of micropores is less than 10 nm.

3. The highly selective blood low-density lipoprotein adsorption resin according to claim 1, characterized in that, The resin matrix is ​​selected from one of styrene-divinylbenzene copolymer, polyvinyl alcohol or its modified materials, cellulose and its modified products, agarose and its modified products, or chitosan and its modified products.

4. The highly selective blood low-density lipoprotein adsorption resin according to claim 1, characterized in that, The resin particles have a ligand fixed in the middle layer or pores, and the ligand is a polypeptide with apolipoprotein recognition capability; the polypeptide is a lysine-glycine-lysine tripeptide.

5. The highly selective blood low-density lipoprotein adsorption resin according to claim 1, characterized in that, The outer surface of the resin particles is provided with an anti-protein contamination layer, and the anti-protein contamination layer material is one of polyethylene glycol, zwitterionic polymer or hydrophilic polymer.

6. The highly selective blood low-density lipoprotein adsorption resin according to claim 1, characterized in that, The specific surface area of ​​the resin particles is 100-600 m². 2 / g, with a particle size of 50–300μm.

7. A method for preparing a gradient crosslinking resin for highly selective adsorption of low-density lipoprotein in blood, characterized in that, Includes the following steps: 1) Porous polymer microspheres were prepared by suspension polymerization; 2) By contacting the microspheres with a crosslinking agent and controlling the diffusion process of the crosslinking agent from the outside to the inside, the microspheres form a gradient crosslinking structure with a gradually decreasing degree of crosslinking from the outside to the inside; 3) The resin is subjected to a functional group introduction treatment; 4) Immobilize functional ligands onto resin particles; 5) Modify the surface of the resin particles.

8. The method for preparing a gradient crosslinking resin for highly selective blood low-density lipoprotein adsorption according to claim 7, characterized in that, Gradient crosslinking is as follows: The degree of cross-linking of the outer layer is 30%–50%; The cross-linking degree of the intermediate layer is 15%–30%; The degree of cross-linking in the core is 5% to 15%.

9. The method for preparing a gradient crosslinking of a highly selective blood low-density lipoprotein adsorption resin according to claim 7, characterized in that, Step 2) The crosslinking agent has a mass fraction of 5% to 30%; The swelling time is 10–60 min; The cross-linking reaction time is 0.5–6 hours; The reaction temperature is 40–80℃.

10. The method for preparing a gradient crosslinking of a highly selective blood low-density lipoprotein adsorption resin according to claim 9, characterized in that, The crosslinking agent includes at least one of divinylbenzene, N,N'-methylenebisacrylamide, and glutaraldehyde.

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