Surface treatment method for improving immunocompatibility of implantable medical device

Abstract

The present invention relates to the technical field of medical materials. Disclosed is a surface treatment method for improving the immunocompatibility of an implantable medical device by means of silane coupling agent treatment. The silane coupling agent has the following structural formula, wherein R1, R2 and R3 are independently chlorine, hydroxyl, methyl, methoxy, ethoxy, or trimethylsiloxy; L is-(CH2)n-, wherein n is an integer from 0 to 15; and R4 is a sulfonic acid group, a methyl phosphonic acid group, a carboxyl group, or a monoglyceride group. It is found in the present invention that the silane coupling agent with this structure has an excellent anti-foreign body reaction effect and can be used for improving the immunocompatibility of the implantable medical device. The coupling agents with this structure are all existing mature finished products, which do not require further research and development in terms of synthetic preparation processes. The coupling agent can be used as a silane coupling agent material capable of quickly, simply, and conveniently performing surface grafting on biological materials and implantable medical instruments. After implantation, the corresponding product grafted with the silane coupling agent has a significantly improved immunocompatibility.

Description

Surface treatment method for improving the immune compatibility of implantable medical devices TECHNICAL FIELD

[0001] The present application relates to the technical field of medical materials, in particular to a surface treatment method for improving the immune compatibility of implantable medical devices by treating with a silane coupling agent. BACKGROUND

[0002] Foreign body reaction (FBR) is an immune-mediated cascade reaction that can occur in most biomaterials and biomedical devices. Its process mainly includes non-specific adsorption of proteins, infiltration of inflammatory cells such as neutrophils and macrophages, and fibrotic reaction induced by fibroblasts. The fibrous capsule caused by fibrosis isolates the device from the host body, which is a key obstacle to the application of implantable medical devices. The isolation of the fibrous capsule leads to the decline of the in vivo performance of the implantable device, affecting the signal fidelity after long-term implantation of the device, which is a major challenge in the field of implantable medical devices. At present, the substrates widely used in medical device manufacturing will cause a certain degree of foreign body reaction, and finding new materials with anti-inflammatory and anti-fibrotic functions is expected to fundamentally solve the problem of foreign body reaction and pave the way for the successful application of implantable medical devices in vivo.

[0003] At present, the main strategy to reduce the foreign body reaction of implantable medical devices is to construct an immunocompatible polymer coating on its surface. For example, CN109563199A discloses an amphoteric polymer coating, which has both positive and negative charges due to its structure. The strong hydration ability brought by this can significantly inhibit the adsorption of non-specific proteins (<5ng / cm 2 ) and thus reduce the foreign body reaction.

[0004] For example, US20190134277A1 discloses a series of anti-inflammatory polymer coatings that can be applied to neural implants, which can effectively reduce the foreign body reaction and improve the immunocompatibility of the implant. Even so, the foreign body reaction regulation strategy based on polymer coating still has the following problems in the distance to actual clinical application:

[0005] 1) The current polymer-based coating materials need to be chemically synthesized, and the complexity of their synthesis and purification limits their large-scale promotion and application;

[0006] 2) Traditional anti-foreign body reaction polymer coating construction requires a series of process steps, and it is difficult to obtain ideal coating quality.

[0007] Achieving the stability and safety of implantable medical devices in vivo is still an important problem that has not been solved, and developing materials that can resist the host foreign body reaction for a long time is still a research direction that needs to be actively explored.

[0008] SUMMARY

[0009] The present application aims at the problems in the construction process of the existing polymer coating with anti-foreign body reaction ability, such as complex monomer synthesis, cumbersome coating process and the like, and provides an application of an already industrialized coupling agent in improving the immune compatibility of implantable medical devices. The method can significantly reduce the foreign body reaction caused by implantation, and the use method does not require any chemical synthesis, and the coating preparation method is simple and easy to operate.

[0010] To achieve the above object, the technical scheme adopted by the present application is:

[0011] A surface treatment method for improving the immune compatibility of implantable medical devices, characterized by treating the surface of the medical device with a silane coupling agent, the silane coupling agent having the following structural formula:

[0012] wherein R1, R2, R3 are independently chlorine, hydroxyl, methyl, methoxy, ethoxy or trimethylsiloxy; L is -(CH2)n- wherein n is an integer from 0 to 15; and R4 is a sulfonic acid group, a methyl phosphoric acid group, a carboxyl group or a monoglyceride group. n

[0013] The inventors have unexpectedly found that the silane coupling agent with the above structure has excellent anti-foreign body reaction effect and can be used to prepare an anti-foreign body reaction coating. These structure coupling agents are all existing mature products, and there is no need to research and develop the synthesis and preparation process, so that the silane coupling agent material can be quickly and simply grafted on the surface of the biomaterial and the implantable medical device. After implantation, the corresponding product grafted with the silane coupling agent has significantly improved immune compatibility.

[0014] In some embodiments, R1, R2, R3 are selected from hydroxyl and methoxy.

[0015] In some embodiments, L is -(CH2)3-.

[0016] In some embodiments, R4 is selected from a sulfonic acid group and a methyl phosphoric acid group. The applicant has found through animal experiments that the compound with this substituent has more durable and stable anti-foreign body reaction effect.

[0017] In some embodiments, R1, R2, R3 are hydroxyl, L is -(CH2)3-, and R4 is a sulfonic acid group.

[0018] In some embodiments, R1, R2, R3 are hydroxyl, L is -(CH2)3-, and R4 is a methyl phosphoric acid group.

[0019] In some embodiments, the step of treating the surface of the medical device with the silane coupling agent comprises the following steps:

[0020] ​Step 1, cleaning and plasma activation treatment on the surface of the medical device material;

[0021] Step 2, contacting the activated biomaterial with the solution of silane coupling agent to perform surface silanization grafting reaction, and obtaining the improved implantable medical device after cleaning.

[0022] The present application utilizes the characteristics that silane coupling agent can quickly hydrolyze hydroxyl groups and quickly condense with the hydroxyl groups on the substrate, and can realize silanization grafting reaction by simple contact with the surface of the biomaterial, obtain medical devices with excellent immunocompatibility, and the preparation method is very simple and feasible, avoiding complex chemical synthesis reaction, and easy to realize the popularization and application of process.

[0023] In some embodiments, the plasma activation time in step 1 is 0.5-120 min;

[0024] In some embodiments, the mass concentration of the solution of silane coupling agent in step 2 is 0.01wt%-10wt%;

[0025] In some embodiments, the contacting time for surface silanization grafting reaction in step 2 is 0.1-72 h, and the temperature is 0-60℃;

[0026] In some embodiments, the contact angle of the surface of the treated substrate is 5-40°;

[0027] In some embodiments, the proportion of sulfur element or phosphorus element on the surface of the treated substrate is 2%-10% after X-ray photoelectron spectroscopy (XPS) test;

[0028] In some embodiments, the thickness of the surface silane coupling agent layer on the surface of the treated substrate is 5-40 nm after ellipsometry test.

[0029] The biomaterials include but are not limited to:

[0030] (1) high molecular materials: polysiloxane, polyurethane, polyolefin, polyester, polyamide, polyether, polysulfone, polyketone, polyacrylate, polymethacrylate, polyether ether ketone, polytetrafluoroethylene, polyvinyl chloride, polystyrene, polycarbonate, polyacrylonitrile, polylactic acid, polyglycolide, polylactide, polycaprolactone, ethylene-octene copolymer, polyimide, and copolymers and blends of the above materials;

[0031] (2) inorganic materials: silicon dioxide, glass, titanium dioxide, carbon material, silicon, titanium nitride, calcium phosphate, hydroxyapatite, etc.;

[0032] (3) metal materials: stainless steel, titanium and its alloys, cobalt-based alloy, nickel-titanium alloy, magnesium and its alloys, zinc and its alloys, iron and its alloys, etc.

[0033] The processed medical device substrate is used as an implantable medical product or an implantable device.

[0034] The implantable medical device includes, but is not limited to, a prosthesis, an indwelling needle, an implantable catheter, an implantable electrode, an implantable sensor, a cochlear implant, a pacemaker, an implantable defibrillator, an orthopedic product, a valve, a stent, an implantable drug controlled release device, an implantable cell loading device, an implantable blood glucose monitor, an insulin pump, a brain-computer interface, an artificial lens, an artificial organ, and other implantable devices.

[0035] Compared with the prior art, the present application has the following beneficial effects:

[0036] (1) The present application finds that a type of commercial silane coupling agent can have excellent anti-foreign body reaction effect, and the anti-foreign body reaction effect is long-term stable, the silane coupling agent does not need further chemical synthesis research or purification steps, and provides a new solution and idea for anti-foreign body reaction biological medical materials.

[0037] (2) The silane coupling agent found in the present application can realize the chemical modification of the surface of the biological material through simple soaking contact, the preparation method is very simple, the operability is strong, and is widely applicable to various materials and is suitable for different shaped implant surfaces; after implantation, the corresponding product grafted with the silane coupling agent has significantly improved immunocompatibility. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is the structure of the silane coupling agent used for surface modification.

[0039] Figure 2 is the water contact angle of the silica gel surface modified by different silane coupling agents.

[0040] Figure 3 is a quantitative comparison of the macrophage infiltration degree of the silica gel sheet modified by the silane coupling agent after being implanted subcutaneously on the back of a mouse for two weeks by F4 / 80 immunohistochemical section.

[0041] Figure 4 is a quantitative comparison of the fibroblast infiltration degree of the silica gel sheet modified by the silane coupling agent after being implanted subcutaneously on the back of a mouse for two weeks by α-SMA immunohistochemical section.

[0042] Figure 5 is a quantitative comparison of the fibrosis degree of the silica gel sheet modified by the silane coupling agent after being implanted subcutaneously on the back of a mouse for two weeks by Masson three-color immunohistochemical section.

[0043] Figure 6 is a quantitative comparison of the fibrosis degree of the silica gel sheet modified by the silane coupling agent after being implanted subcutaneously on the back of a mouse for one month by Masson three-color immunohistochemical section.

[0044] Figure 7 shows the F4 / 80 immunohistochemical sections, α-SMA immunohistochemical sections, and Masson trichrome immunohistochemical sections corresponding to the representative silane coupling agent-modified silicone sheet material with good function of inhibiting macrophage and fibroblast infiltration and reducing fibrotic reaction.

[0045] FIG8 shows the density statistics of collagen capsules in Masson trichrome immunohistochemistry sections of a representative silane coupling agent-modified silicone sheet material with good function of reducing fibrosis response, which was implanted subcutaneously on the back of mice for two weeks and one month.

[0046] FIG9 is a quantitative comparison of the degree of fibrosis of the silicone sheet modified with silane coupling agent and implanted subcutaneously in the back of mice three months after the implantation by Masson trichrome immunohistochemistry.

[0047] FIG10 shows the density statistics of collagen capsules in Masson trichrome immunohistochemistry sections of a representative silane coupling agent-modified silicone sheet material having good function of reducing fibrosis response, which was implanted subcutaneously on the back of mice three months later.

[0048] Figure 11 shows the comparison of the degree of fibrosis and collagen capsule density of polyurethane, polyethylene terephthalate, polyvinyl chloride, and polycarbonate sheets modified with silane coupling agents after subcutaneous implantation in the back of mice for one month using Masson trichrome immunohistochemistry sections.

[0049] FIG12 shows dark-field microscopic images of polystyrene, glass, and stainless steel microspheres modified with silane coupling agents and statistics of surface fibrosis levels one month after implantation into the mouse peritoneal cavity. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiment. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Those skilled in the art will make modifications or equivalent substitutions based on understanding the technical solution of the present invention, without departing from the spirit and scope of the technical solution of the present invention, and all should be encompassed within the protection scope of the present invention.

[0051] The raw materials used in the following specific embodiments were purchased from the market. 3-(Trihydroxysilyl)-propanesulfonic acid (A3) and 3-trihydroxysilylpropylmethylphosphate sodium salt (A5) were used as representative immunocompatible silane coupling agents, but this does not limit the present invention.

[0052] Comparative Example 1

[0053] Twenty-seven silane coupling agents with different structures were used as controls, including A2, A4, A6-A30 (Figure 1). Among them, A1 is blank, and the following takes A2 as an example to show the preparation method of the silane coupling agent modified PDMS material, and the rest of the silane coupling agents are modified by the same method:

[0054] Step 1, plasma activation treatment: place the PDMS sheet in a beaker, add enough ultrapure water, and clean it in an ultrasonic cleaning machine for 5 min, then replace the liquid in the beaker with anhydrous ethanol and clean it again for 5 min. After cleaning, dry the substrate under a nitrogen stream, then place it in a plasma cleaning machine and treat it for 3 min at a frequency of 13.56 MHz to perform surface hydroxylation.

[0055] Step 2, silanization treatment of the substrate: dissolve A2 silane coupling agent in deionized water to a concentration of 1 wt%, and immerse the above treated substrate material in the obtained solution, soak at 37°C for 24 h, then wash twice in deionized water, and take out to obtain A2 surface grafted PDMS material.

[0056] Other silane coupling agent grafted PDMS materials are prepared according to the above method.

[0057] Example 1

[0058] Preparation of representative immunocompatible silane coupling agent A3 (structure as shown in Figure 1) grafted polydimethylsiloxane (PDMS) material:

[0059] Step 1, plasma activation treatment: place the PDMS sheet in a beaker, add enough ultrapure water, and clean it in an ultrasonic cleaning machine for 5 min, then replace the liquid in the beaker with anhydrous ethanol and clean it again for 5 min. After cleaning, dry the substrate under a nitrogen stream, then place it in a plasma cleaning machine and treat it for 3 min at a frequency of 13.56 MHz to perform surface hydroxylation.

[0060] Step 2, silanization treatment of the substrate: dissolve A3 silane coupling agent in deionized water to a concentration of 1 wt%, and immerse the above treated substrate material in the obtained solution, soak at 37°C for 24 h, then wash twice in deionized water, and take out to obtain A3 surface grafted PDMS material.

[0061] Example 2

[0062] Preparation of representative immunocompatible silane coupling agent A5 (structure as shown in Figure 1) grafted polydimethylsiloxane (PDMS) material:

[0063] Step 1, Plasma activation treatment: Put the PDMS sheet in a beaker, add enough ultrapure water, and clean it in an ultrasonic cleaner for 5 min. Then change the liquid in the beaker to anhydrous ethanol and clean it again for 5 min. After cleaning, dry the substrate under a stream of nitrogen and then place it in a plasma cleaner for 3 min at a frequency of 13.56 MHz to perform surface hydroxylation.

[0064] Step 2, Silanization treatment of the substrate: Dissolve A5 silane coupling agent in deionized water to a concentration of 1 wt%, and immerse the above-processed substrate material in the resulting solution. Soak at 37°C for 24 h, then rinse twice in deionized water. The A5 surface-grafted PDMS material is obtained after removal.

[0065] Example 3

[0066] Preparation of a representative immunocompatible silane coupling agent A3 grafted polystyrene microsphere material:

[0067] Step 1, Plasma activation treatment: Put the polystyrene microspheres in a petri dish and place them in a plasma cleaner for 3 min at a frequency of 13.56 MHz to perform surface hydroxylation.

[0068] Step 2, Silanization treatment of the microspheres: Dissolve A3 silane coupling agent in deionized water to a concentration of 1 wt%, and immerse the above-processed microsphere material in the resulting solution. Soak at 37°C for 24 h, then rinse twice in deionized water. The A3 surface-grafted polystyrene microsphere material is obtained after removal.

[0069] Example 4

[0070] Preparation of a representative immunocompatible silane coupling agent A3 grafted stainless steel microsphere material:

[0071] Step 1, Plasma activation treatment: Put the stainless steel microspheres in a petri dish and place them in a plasma cleaner for 3 min at a frequency of 13.56 MHz to perform surface hydroxylation.

[0072] Step 2, Silanization treatment of the microspheres: Dissolve A3 silane coupling agent in deionized water to a concentration of 1 wt%, and immerse the above-processed microsphere material in the resulting solution. Soak at 37°C for 24 h, then rinse twice in deionized water. The A3 surface-grafted stainless steel microsphere material is obtained after removal.

[0073] Example 5

[0074] Preparation of a representative immunocompatible silane coupling agent A3 grafted glass microsphere material:

[0075] Step 1, Plasma activation treatment: The glass microspheres were placed in a petri dish and surface hydroxylated by placing them in a plasma cleaner for 3 min at a frequency of 13.56 MHz.

[0076] Step 2, Silanization treatment of the microspheres: A3 silane coupling agent was dissolved in deionized water to a concentration of 1 wt%, and the above treated microsphere material was immersed in the resulting solution. After soaking at 37°C for 24 h, the material was rinsed twice in deionized water, and the A3 surface-grafted glass microsphere material was obtained.

[0077] Example 6

[0078] Preparation of a representative immunocompatible silane coupling agent A3 grafted thermoplastic polyurethane (TPU) material:

[0079] Step 1, Plasma activation treatment: The TPU sheet was placed in a beaker, enough ultrapure water was added, and it was cleaned in an ultrasonic cleaner for 5 min. The liquid in the beaker was then replaced with anhydrous ethanol and cleaned again for 5 min. After cleaning, the substrate was dried under a nitrogen stream, and then surface hydroxylated by placing it in a plasma cleaner for 3 min at a frequency of 13.56 MHz.

[0080] Step 2, Silanization treatment of the substrate: A3 silane coupling agent was dissolved in deionized water to a concentration of 1 wt%, and the above treated substrate material was immersed in the resulting solution. After soaking at 37°C for 24 h, the material was rinsed twice in deionized water, and the A3 surface-grafted TPU material was obtained.

[0081] Example 7

[0082] Preparation of a representative immunocompatible silane coupling agent A3 grafted polyethylene terephthalate (PET) material:

[0083] Step 1, Plasma activation treatment: The PET sheet was placed in a beaker, enough ultrapure water was added, and it was cleaned in an ultrasonic cleaner for 5 min. The liquid in the beaker was then replaced with anhydrous ethanol and cleaned again for 5 min. After cleaning, the substrate was dried under a nitrogen stream, and then surface hydroxylated by placing it in a plasma cleaner for 3 min at a frequency of 13.56 MHz.

[0084] Step 2, Silanization treatment of the substrate: A3 silane coupling agent was dissolved in deionized water to a concentration of 1 wt%, and the above treated substrate material was immersed in the resulting solution. After soaking at 37°C for 24 h, the material was rinsed twice in deionized water, and the A3 surface-grafted PET material was obtained.

[0085] Example 8

[0086] Preparation of representative immunocompatible silane coupling agent A3 grafted polyvinyl chloride (PVC) material:

[0087] Step 1, plasma activation treatment: place the PVC sheet in a beaker, add sufficient ultrapure water, and clean it in an ultrasonic cleaning machine for 5 min, then replace the liquid in the beaker with anhydrous ethanol and clean it again for 5 min. After cleaning, dry the substrate under a nitrogen stream, then place it in a plasma cleaning machine and treat it for 3 min at a frequency of 13.56 MHz to perform surface hydroxylation.

[0088] Step 2, silanization treatment of the substrate: dissolve A3 silane coupling agent in deionized water to a concentration of 1 wt%, and immerse the above-processed substrate material in the resulting solution, soak it at 37°C for 24 h, then wash it twice in deionized water, and take it out to obtain the A3 surface-grafted PVC material.

[0089] Example 9

[0090] Preparation of representative immunocompatible silane coupling agent A3 grafted polycarbonate (PC) material:

[0091] Step 1, plasma activation treatment: place the PC sheet in a beaker, add sufficient ultrapure water, and clean it in an ultrasonic cleaning machine for 5 min, then replace the liquid in the beaker with anhydrous ethanol and clean it again for 5 min. After cleaning, dry the substrate under a nitrogen stream, then place it in a plasma cleaning machine and treat it for 3 min at a frequency of 13.56 MHz to perform surface hydroxylation.

[0092] Step 2, silanization treatment of the substrate: dissolve A3 silane coupling agent in deionized water to a concentration of 1 wt%, and immerse the above-processed substrate material in the resulting solution, soak it at 37°C for 24 h, then wash it twice in deionized water, and take it out to obtain the A3 surface-grafted PC material.

[0093] Performance characterization

[0094] The silane coupling agent-grafted PDMS materials prepared in Example 1, Example 2, and Comparative Example 1 were characterized for hydrophilicity, and the surface contact angles are shown in FIG. 2, in which the surfaces of A3, A5, and A6 after grafting have higher hydrophilicity. The XPS test showed that the proportion of sulfur elements on the surface of A3 was 3.04%, and the proportion of phosphorus elements on the surface of A5 was 5.44%. The ellipsometric test showed that the thickness of the silane coupling agent layer on the surface of A3 was 14.31 ± 2.86 nm.

[0095] Application example

[0096] In vivo related inflammatory response of representative immunocompatible silane coupling agent-grafted PDMS material

[0097] I. Animal surgery procedure

[0098] C57BL / 6 mouse subcutaneous implant model

[0099] The implantation process of representative immunocompatible silane coupling agent grafted PDMS materials in a mouse subcutaneous implant model is demonstrated in this application example. The surface-modified PDMS materials prepared as in Example 1, Example 2, and Comparative Example 1 were cut into discs using a biophysics punch (4 mm in diameter, ~1 mm in thickness). The samples were sterilized with 75% ethanol, washed with normal saline, and implanted subcutaneously in C57BL / 6 female mice. The samples were implanted in different areas of the back of the mice, respectively. The implantation procedure was as follows:

[0100] The mice were anesthetized with isoflurane gas, shaved, and the skin was disinfected with iodine. A longitudinal incision of about 8 mm was made on the dorsal surface using surgical scissors to provide access to the subcutaneous space. A subcutaneous pocket was then created at about 0.5 cm from the incision using blunt forceps for implantation of the sample. After implantation, the incision was closed using 5-0 tapered tip PGA absorbable suture.

[0101] The mice were monitored until recovery from anesthesia and were housed for 2 weeks, 4 weeks, 3 months, or longer, respectively. The mice grew normally after implantation without any signs of discomfort, and no weight loss was observed before the implants were removed.

[0102] C57BL / 6 mouse intraperitoneal implant model

[0103] The implantation process of representative immunocompatible silane coupling agent grafted PDMS materials in a mouse intraperitoneal implant model is demonstrated in this application example. The surface-modified microsphere materials prepared as in Example 3-5 were sterilized with 75% ethanol, washed with normal saline, and implanted intraperitoneally in C57BL / 6 female mice. The implantation procedure was as follows:

[0104] The mice were anesthetized with isoflurane gas and the abdominal skin was disinfected with iodine. A longitudinal incision of about 8 mm was made on the abdomen using surgical scissors to provide access to the intraperitoneal space. The microsphere materials were then implanted. After implantation, the incision was closed using 5-0 tapered tip PGA absorbable suture.

[0105] The mice were monitored until recovery from anesthesia and were housed for 2 weeks, 4 weeks, 3 months, or longer, respectively. The mice grew normally after implantation without any signs of discomfort, and no weight loss was observed before the implants were removed.

[0106] II. Inflammation response of representative immunocompatible silane coupling agent grafted PDMS materials in vivo

[0107] Macrophage and fibroblast immunohistochemical sections

[0108] The experiment process describes the inflammatory response of the immunocompatible silane coupling agent grafted PDMS material in the mouse subcutaneous implantation model.

[0109] The implanted materials and the surrounding tissue samples were removed from the mice after two weeks, fixed in 10% formaldehyde solution for 24 hours, and embedded with paraffin. Each sample was cut into a thickness of 3-5 μm and mounted on a glass slide for histological staining. Rabbit anti-mouse F4 / 80 monoclonal antibody was from Abeam (dilution 1:500; catalog number ab300421), and mouse anti-mouse α-SMA monoclonal antibody was from Biodee (1:400; catalog number BM0002). Before immunization, antigen retrieval, endogenous peroxidase elimination, and bovine serum albumin blocking were performed in sequence. The sample slices after two weeks of implantation were incubated with primary antibodies overnight at 4°C. The slices were washed with PBS three times and incubated with HRP-labeled goat anti-rabbit antibody (1:300; catalog number SE134 from Solarbio) or HRP-labeled goat anti-mouse antibody (1:200; catalog number GB23301 from Servicebio) for 50 minutes at room temperature in the dark. The slices were washed three times, slightly dried, and then incubated with freshly prepared diamine.

[0110] The macrophage infiltration degree of the silica gel sheets modified by different silane coupling agents after two weeks of subcutaneous implantation in the back of mice was quantitatively compared by F4 / 80 immunohistochemical slice as shown in FIG. 3, and the fibroblast infiltration degree of the silica gel sheets modified by different silane coupling agents after two weeks of subcutaneous implantation in the back of mice was quantitatively compared by α-SMA immunohistochemical slice as shown in FIG. 4.

[0111] In FIGS. 3 and 4, the recruitment of macrophages and fibroblasts after implantation of each sample was quantitatively analyzed according to the immunohistochemical slices, and the results showed that the inflammation reaction induced by the substrate could be greatly reduced after grafting of A3 and A5.

[0112] The F4 / 80 immunohistochemical slices, α-SMA immunohistochemical slices, and Masson trichrome immunohistochemical slices of the silica gel sheet materials of PDMS, A2, A3, and A5 are shown in FIG. 7. It can be observed from FIG. 7 that a large number of macrophages and fibroblasts were recruited near the samples of PDMS and A2 grafted PDMS after two weeks of implantation, while there was almost no infiltration of the two cells near the samples of A3 and A5 grafted samples.

[0113] III. Fibrosis reaction of representative immunocompatible silane coupling agent grafted PDMS material in vivo

[0114] C57BL / 6 mouse subcutaneous implantation model

[0115] The experiment describes the fibrotic response of the immunocompatible silane coupling agent grafted PDMS materials in the subcutaneous implantation model in mice.

[0116] The implanted samples and the tissue samples near the implant were removed, fixed in 10% formaldehyde solution for 24 hours, and embedded with paraffin. Each sample was sliced with a thickness of 3-5 μm and mounted on a glass slide for histological staining. The inflammatory response was examined by staining the tissue sections with hematoxylin and eosin (H&E), which stains the cell nucleus blue and the cytoplasm pink. The formation of collagen and the tissue were stained with Masson's trichrome staining, which stains collagen blue, cytoplasm red, and cell nucleus black.

[0117] All images were scanned in a bright field microscope (Nikon intensilight CHGFI) equipped with NIS Elements AR software. The collagen thickness was obtained by measuring the thickness of the dense collagen capsules stained blue in the Masson images (step size 100 μm) of the material-tissue interface. The degree of fibrosis of the immunocompatible silane coupling agent grafted PDMS materials after subcutaneous implantation in the back of mice was compared by Masson's trichrome immunohistochemical sections. The short-term anti-fibrotic function of the materials was first screened, and the fibrous capsule density statistics of the control samples in Example 1, Example 2, and Comparative Example 1 after implantation for two weeks and one month are shown in Figures 5 and 6.

[0118] It can be seen that A3, A5, A6, A7, and A8 have relatively good anti-fibrotic effects. Then, long-term anti-fibrotic studies were conducted on representative samples with good immunocompatibility.

[0119] The density statistics of the collagen capsules in the Masson's trichrome immunohistochemical sections of the silica gel sheet materials modified by A2, A3, and A5 after subcutaneous implantation in the back of mice for two weeks and one month are shown in Figure 8.

[0120] The degree of fibrosis of the silica gel sheets modified by A3, A5, A6, A7, and A8 silane coupling agents after subcutaneous implantation in the back of mice for three months was quantitatively compared by Masson's trichrome immunohistochemical sections, and the results are shown in Figure 9.

[0121] The density statistics of the collagen capsules in the Masson's trichrome immunohistochemical sections of the silica gel sheet materials modified by A1, A3, A5, A6, A7, and A8 after subcutaneous implantation in the back of mice for three months are shown in Figure 10.

[0122] As can be seen from FIG. 7 and FIG. 9, after one month and three months of implantation, the A3 and A5 samples can effectively reduce the fibrosis reaction caused by PDMS, compared with the untreated PDMS and A2 grafted samples. As can be seen from the fibrosis density statistics of FIG. 8 and FIG. 10, A6, A7, and A8 can reduce the fibrosis reaction after PDMS implantation to a certain extent, and A3 and A5 samples can significantly reduce the fibrosis reaction after two weeks, one month, and three months of implantation.

[0123] In addition, we also tested the modification effect of the silane coupling agent on various polymer substrates. The fibrosis reaction after one month of subcutaneous implantation of the materials in mice as in Example 6 to Example 9 was tested, and the results are shown in FIG. 11 (a is the Masson section of the implanted material, and b is the statistical situation of collagen capsule density). The results show that various polymer substrates grafted with A3 all exhibit significantly reduced fibrosis degree, which means that the modification of A3 is widely applicable to various substrates and can significantly improve the immunocompatibility thereof.

[0124] C57BL / 6 mouse intraperitoneal implantation model

[0125] The experiment process is used to describe the fibrosis reaction of the immunocompatible silane coupling agent grafted PDMS material in the mouse intraperitoneal implantation model.

[0126] The implanted sample in the mouse was taken out, fixed in 10% formaldehyde solution for 24 hours, and then the morphology of the removed material was observed under a stereomicroscope. As shown in FIG. 12 (a is the sample taken out from the intraperitoneal cavity taken by dark field microscope, and b is the relative collagen content on the surface of the recovered sample), the polystyrene, glass, and stainless steel microspheres grafted with A3 all exhibit significantly lower fibrous tissue coating than the unmodified samples. After the sample was digested with various enzymes (trypsin, collagenase, lipase), the collagen content on the surface of the sample was calculated according to the weight change, and the results show that the sample grafted with A3 has lower fibrous tissue coating after implantation, which means lower foreign body reaction level after implantation.

Claims

1. A surface treatment method for improving the immune compatibility of implantable medical devices, characterized in that: The surface of the medical device is treated with a silane coupling agent having the following structural formula: Wherein: R1, R2, R3 are independently chlorine, hydroxyl, methyl, methoxy, ethoxy or trimethylsilyloxy; L is -(CH2) n -, wherein n is an integer from 0 to 15; R4 is a sulfonic acid group, a methylphosphonic acid group, a carboxyl group or a monoglyceride group.

2. The surface treatment method for improving the immune compatibility of implantable medical devices according to claim 1, characterized in that: Wherein R1, R2, and R3 are selected from hydroxyl and methoxy; and / or, L is -(CH2)3-.

3. The surface treatment method for improving the immune compatibility of implantable medical devices according to claim 1, characterized in that: wherein R4 is selected from sulfonic acid group and methylphosphonic acid group.

4. The surface treatment method for improving the immune compatibility of implantable medical devices according to claim 1, characterized in that: Wherein R1, R2, and R3 are hydroxyl groups, L is -(CH2)3-, and R4 is a sulfonic acid group.

5. The surface treatment method for improving the immune compatibility of implantable medical devices according to claim 1, characterized in that: Wherein R1, R2, and R3 are hydroxyl groups, L is -(CH2)3-, and R4 is a methylphosphonic acid group.

6. The surface treatment method for improving the immune compatibility of implantable medical devices according to claim 1, characterized in that: Treating the surface of medical devices with silane coupling agents involves the following steps: Step 1: Cleaning and plasma activation of the surface of medical device materials; Step 2: contacting the activated biomaterial with the solution of the silane coupling agent to carry out a surface silanization grafting reaction, and obtaining an improved implantable medical device after cleaning.

7. The surface treatment method for improving the immune compatibility of implantable medical devices according to claim 6, characterized in that: The plasma activation time in step 1 is 0.5 to 120 minutes; And / or, the mass concentration of the silane coupling agent solution in step 2 is 0.01wt% to 10wt%; And / or, the surface silanization grafting reaction time in step 2 is 0.1 to 72 hours, and the temperature is 0 to 60°C.

8. The surface treatment method for improving the immune compatibility of implantable medical devices according to claim 6, characterized in that: The improved contact angle of the implantable medical device surface is 5 to 40°; and / or, the percentage of sulfur or phosphorus on the surface of the improved implantable medical device is 2% to 10%; And / or, the thickness of the silane coupling agent layer on the surface of the improved implantable medical device is 5 to 40 nm.

9. The surface treatment method for improving the immune compatibility of implantable medical devices according to claim 1, characterized in that: The substrate of the medical device includes any one or more of the following materials: (1) Polymer materials: copolymers and blends of polysiloxane, polyurethane, polyolefin, polyester, polyamide, polyether, polysulfone, polyketone, polyacrylate, polymethacrylate, polyetheretherketone, polytetrafluoroethylene, polyvinyl chloride, polystyrene, polycarbonate, polyacrylonitrile, polylactic acid, polyglycolide, polylactide, polycaprolactone, ethylene-octene copolymer, and polyimide; (2) Inorganic materials: silicon dioxide, glass, titanium dioxide, carbon materials, silicon, titanium nitride, calcium phosphate, hydroxyapatite; (3) Metal materials: stainless steel, titanium and its alloys, cobalt-based alloys, nickel-titanium alloys, magnesium and its alloys, zinc and its alloys, iron and its alloys.

10. The surface treatment method for improving the immune compatibility of implantable medical devices according to claim 1, characterized in that: The implantable medical devices include any one of prostheses, indwelling needles, implantable catheters, implantable electrodes, implantable sensors, cochlear implants, pacemakers, implantable defibrillators, orthopedic products, valves, stents, implantable drug release devices, implantable cell loading devices, implantable blood glucose monitors, insulin pumps, brain-computer interfaces, artificial lenses, artificial organs and other implantable devices.

Images