阅读说明：本技术 心血管植入器械耐磨损涂层及其制备方法 (Cardiovascular implantation instrument wear-resistant coating and preparation method thereof ) 是由 张晏齐 王松 卢俊哲 祝佳 陈昌盛 李小丽 刘伟强 于 2021-01-13 设计创作，主要内容包括：本发明涉及心血管植入器械耐磨损涂层及其制备方法。耐磨损涂层从基体材料开始,依次制备钛过渡层、Ti:C含量比递减的含钛梯度层和Cu-DLC含铜非晶碳层,即Ti/Ti:C/Cu-DLC复合涂层；含钛梯度层为钛、碳含量梯度变化的非晶碳层,钛过渡层为钛单质。制备方法,包括：⑴对植入器械金属基体材料表面抛光、清洗；⑵将基体材料放入真空室预处理；⑶在真空室内产生Ti离子,使其移动到基体材料表面沉积成型钛过渡层；⑷同时产生Ti离子和C离子,使其移动到基体材料表面沉积,逐渐调整二者产生比例,成型含钛梯度层；⑸同时产生C离子和Cu离子,使其移动到基体材料表面并沉积,成型含铜非晶碳层。(The invention relates to an abrasion-resistant coating of a cardiovascular implantation instrument and a preparation method thereof. The wear-resistant coating is prepared by sequentially preparing a titanium transition layer, a titanium-containing gradient layer with the content ratio of Ti to C decreasing and a Cu-DLC copper-containing amorphous carbon layer from a base material, namely a Ti/Ti: C/Cu-DLC composite coating; the titanium-containing gradient layer is an amorphous carbon layer with gradient change of titanium and carbon content, and the titanium transition layer is a titanium simple substance. The preparation method comprises the following steps: the method comprises the steps of polishing and cleaning the surface of an implanted mechanical metal matrix material; placing a matrix material into a vacuum chamber for pretreatment; thirdly, Ti ions are generated in the vacuum chamber and are moved to the surface of the base material to deposit a formed titanium transition layer; fourthly, Ti ions and C ions are generated simultaneously, the Ti ions and the C ions are moved to the surface of the base material to be deposited, the generation proportion of the Ti ions and the C ions is gradually adjusted, and a titanium-containing gradient layer is formed; and fifthly, simultaneously generating C ions and Cu ions, moving the C ions and the Cu ions to the surface of the base material, depositing, and forming the copper-containing amorphous carbon layer.)

1. The wear-resistant coating for the cardiovascular implantation instrument is characterized in that the wear-resistant coating is prepared by sequentially preparing a titanium transition layer, a titanium-containing gradient layer with the content ratio of Ti to C being gradually reduced and a Cu-DLC copper-containing amorphous carbon layer from a base material, namely preparing a Ti/Ti: C/Cu-DLC composite coating; the titanium-containing gradient layer is an amorphous carbon layer with gradient change of titanium and carbon contents, and the titanium transition layer is a titanium simple substance; the thickness of the wear-resistant coating is 1.6-2.4 microns.

2. The wear-resistant coating for the cardiovascular implantation instrument as claimed in claim 1, wherein the copper content of the copper-containing amorphous carbon layer is 5 at% to 20 at%, and the carbon sp2 hybridization ratio is more than 50%; the hybridization proportion of the carbon sp2 of the titanium-containing gradient layer is 20-60%; the thickness of the copper-containing amorphous carbon layer is 800-1200 nm; the thickness of the titanium-containing gradient layer is 600-800 nm; the thickness of the titanium transition layer is 200-400 nm.

3. The cardiovascular implant device abrasion-resistant coating according to claim 1, wherein the implant device is comprised of a braided filamentary material, including at least one filamentary member, and the filamentary member is subjected to friction.

4. A preparation method of an abrasion-resistant coating of a cardiovascular implantation instrument is characterized by comprising the following steps:

polishing and cleaning the surface of a metal matrix material of the implantation instrument;

secondly, putting the cleaned matrix material into a vacuum chamber and carrying out pretreatment;

thirdly, Ti ions are generated in the vacuum chamber and are moved to the surface of the base material to be deposited to form a titanium transition layer;

fourthly, Ti ions and C ions are generated in the vacuum chamber at the same time, the Ti ions and the C ions are moved to the surface of the base material to be deposited, the generation ratio of the Ti ions and the C ions is gradually adjusted, and a titanium-containing gradient layer is formed;

fifthly, simultaneously generating C ions and Cu ions in the vacuum chamber, moving the C ions and the Cu ions to the surface of the base material and depositing to form the copper-containing amorphous carbon layer.

5. The preparation method of the wear-resistant coating for the cardiovascular implant instrument according to claim 4 is characterized by comprising the steps of grinding and polishing the base material to the surface roughness Ra0.05 μm or less, ultrasonically cleaning the base material in acetone or absolute ethyl alcohol for 15-30 minutes, ultrasonically cleaning the base material in deionized water for 15-30 minutes, and finally drying the base material in a vacuum drying oven for more than 18 hours for later use.

6. The method for preparing the wear-resistant coating of the cardiovascular implant device according to claim 4, wherein the pretreatment further comprises the following steps: placing the substrate material into a vacuum chamber with a pressure of less than 5.0 × 10^-3Pa, adjusting the flow of argon gas to make the pressure of the vacuum chamber reach 1Pa, and adjusting the bias voltage power supply to be more than 800V, thereby cleaning the surface of the metal part of the medical instrument by using the argon ion beam for at least 5 minutes.

7. The method for preparing the wear-resistant coating of the cardiovascular implant device according to claim 4, wherein the step of obtaining the titanium transition layer further comprises: making the air pressure in the vacuum chamber less than 5.0 x 10^-3Pa, heating the substrate material to 200-300 ℃, keeping the temperature, and introducing argon to ensure that the vacuum chamber is aeratedKeeping the pressure at 0.5-1.5 Pa, adjusting the bias voltage power supply to 300-600V, setting the sputtering current of the titanium target to be a constant value within the interval of 4-6A, thereby generating Ti ions, enabling the Ti ions to move towards the base material under the action of the bias voltage, depositing for 10-20 minutes, and finally depositing a Ti transition layer on the surface of the base material.

8. The method for preparing the anti-abrasion coating of the cardiovascular implant device according to claim 4, wherein the step of obtaining the titanium-containing gradient layer further comprises: maintaining the air pressure and temperature in the step three, adjusting the bias power supply to 200-400V, starting the titanium target and the graphite target power supply, controlling the sputtering current of the titanium target to be gradually reduced from 3A to less than 0.2A, and the sputtering current of the graphite target to be gradually increased from 0 to 4.5A, simultaneously generating Ti ions and C ions, enabling the Ti ions and the C ions to move towards the base material under the action of bias voltage, depositing for 40-100 minutes, and finally depositing a Ti: C gradient buffer layer on the surface of the base material.

9. The method for preparing the wear-resistant coating for the cardiovascular implant device according to claim 4, wherein the step of obtaining the copper-containing amorphous carbon coating further comprises: and step four, maintaining the air pressure and the temperature, turning off the power supplies of the titanium target and the graphite target, adjusting the bias power supply to 100-300V, turning on the power supplies of the copper target and the graphite target, controlling the sputtering current of the copper target to be 0.1-2A and the sputtering current of the graphite target to be 3-6A, simultaneously generating Cu ions and C ions, enabling the Cu ions and the C ions to move to the base material under the action of bias voltage, depositing for 1.5-4 hours, and finally depositing the amorphous carbon layer containing copper on the surface of the base material.

10. The method for preparing the wear-resistant coating of the cardiovascular implant instrument, according to claim 4, wherein the Ti ions, the C ions and the Cu ions are generated by a sputtering method in the steps from the step three to the step fifthly.

Technical Field

The invention belongs to the technical field of medical instruments, and particularly relates to a wear-resistant coating of a cardiovascular implantation instrument and a preparation method thereof. Cardiovascular implant devices wear resistant coatings are applied to worn filamentary members of the device.

Background

Cardiovascular diseases are one of the main causes of death of human diseases, and the implantation of medical devices is an effective treatment means for the diseases. The clinical common cardiovascular implantation instruments such as blood vessel stents, occluders, venous thrombus filters and the like can be prepared by weaving filamentous materials. However, in the woven implantation device, due to the direct contact between the filamentous materials, under the action of physiological motion load and a body fluid environment of an implantation part, serious fretting corrosion abrasion is generated between the filaments. The metal ions or abrasive dust particles released by abrasion can promote inflammatory reaction and even block blood vessels, thereby causing severe diseases such as restenosis in the stent and the like.

A diamond-like carbon (DLC) film is an amorphous carbon film, which is mainly composed of carbon elements. DLC films have the advantages of high hardness, low coefficient of friction, low wear rate, bioinert, and the like, but also have high brittleness, high internal stress, and poor film-substrate bonding strength. The current research shows that the brittleness and the internal stress can be effectively improved by proper doping of heterogeneous elements; the film-substrate bonding strength can be effectively improved through reasonable transition structure design.

Copper is one of the essential trace elements for the human body, and the concentration of copper in the plasma of a normal human is about 100 mug/dL. Copper deficiency can lead to diseases including anemia, arthritis, and various cardiovascular diseases. Studies by Sen Chandan K et al indicate that copper can promote the expression of the endothelial growth factor VEGF, thereby promoting the proliferation of vascular endothelial cells; McCarthy et al demonstrated that Fe is present during corrosion of the vascular stent²⁺And Cu²⁺Has the highest catalytic NO release performance, and the latter can inhibit the adhesion and activation of blood platelets. Therefore, a cardiovascular implant containing a suitable amount of copper can effectively promote endothelialization, inhibit smooth muscle proliferation and thrombosis, and avoid in-stent restenosis. However, as the copper content in the coating increases, the rate of hemolysis also increases rapidly; in addition, excessive copper also inhibits endothelial cell proliferation.

Chinese patent document CN 105250058A discloses a lumen woven stent, which solves the contradiction between radial support force and flexibility of the woven stent through the difference design of the first part and the second part and the hook-and-loop structure constructed on the mesh tube body. However, the stent is an uncoated bare metal stent, and there is still a risk of abrasion and corrosion of the filamentary members and restenosis due to heavy metal ion release.

Chinese patent document CN 211460696U discloses a novel blood vessel stent using diamond-like carbon coating, and aims to provide a novel blood vessel stent with smooth surface, low friction coefficient and low surface roughness, and reduce the damage to blood vessels caused by stent implantation. According to the technical scheme, the 2-4 mu m diamond-like coating is uniformly prepared on the intravascular stent, so that the friction coefficient and the surface roughness are reduced. The defects are that the bonding strength between the diamond-like coating and a stent base material is low, and the internal stress of the diamond-like coating without doping of heterogeneous elements is too large, so that the diamond-like coating is easy to crack and peel, and further the failure of the coating is caused. In summary, constructing a proper amount of copper-doped diamond-like carbon (Cu-DLC) coating on the surface of a cardiovascular implant device is expected to greatly reduce the fretting corrosion wear degree and meet the functional requirement of inhibiting restenosis, but the following problems need to be solved:

the difference between the lattice constant and the thermal expansion coefficient of most metal matrix materials and DLC is large, so that the film-substrate bonding strength is insufficient, and the film can crack or even flake under the action of balloon expansion or matrix self-expansion in the process of implanting the vascular stent;

secondly, preparing a coating with high copper content on the surface of the implant can cause hemolysis and inhibit cell growth, and excessive copper ions dissolved into blood can cause toxicity locally;

and the intensity of the DLC film can be reduced while the brittleness is reduced by doping copper, and in addition, the original hydrophobicity and roughness of the DLC film can be influenced by doping.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a copper-containing wear-resistant composite coating of a cardiovascular implantation instrument, wherein the coating has good fretting corrosion wear resistance and good blood compatibility, and reduces the risk of vascular restenosis; meanwhile, the coating toughness, internal stress and membrane-substrate bonding strength are improved through doping and structural design, so that the coating is more suitable for the surface interfaces of various implantation instruments including woven vascular stents. The invention aims to solve another technical problem of providing a method for preparing a titanium transition layer, a titanium gradient layer and a copper-containing amorphous carbon layer sequentially from beginning to end of a filiform part which is easy to wear in a cardiovascular implantation device; the part for preparing the copper-containing wear-resistant composite coating has good blood compatibility, can greatly reduce the wear of the part, avoids restenosis in blood vessels caused by heavy metal ion release and abrasive dust release due to wear and wear corrosion, and effectively improves the comprehensive performance of the cardiovascular implant apparatus. The invention aims to solve the other technical problem of providing the preparation method of the cardiovascular implant wear-resistant coating, which effectively solves the problem of fretting wear of the filamentous part of the cardiovascular implant with a braided structure, and simultaneously better ensures that the corrosion resistance, the mechanical property and the biocompatibility of the implant are not obviously reduced or even can be improved, and has practical application value.

The technical scheme of the invention is that the wear-resistant coating of the cardiovascular implantation instrument is characterized in that the wear-resistant coating is prepared by sequentially preparing a titanium transition layer, a titanium-containing gradient layer with a gradually reduced Ti to C content ratio and a Cu-DLC copper-containing amorphous carbon layer from a base material, namely preparing a Ti/Ti to C/Cu-DLC composite coating; the titanium-containing gradient layer is an amorphous carbon layer with gradient change of titanium and carbon contents, and the titanium transition layer is a titanium simple substance; the thickness of the wear-resistant coating is 1.6-2.4 microns.

Preferably, the method comprises the following steps: the copper content of the copper-containing amorphous carbon layer is 5 at% to 20 at%, and the hybridization proportion of carbon sp2 is more than 50%; the hybridization proportion of the carbon sp2 of the titanium-containing gradient layer is 20-60%; the thickness of the copper-containing amorphous carbon layer is 800-1200 nm; the thickness of the titanium-containing gradient layer is 600-800 nm; the thickness of the titanium transition layer is 200-400 nm.

Preferably, the method comprises the following steps: the implant device is constructed of a braided filamentary material including at least one filamentary member, and the filamentary member is subjected to friction.

The invention also provides a preparation method of the wear-resistant coating of the cardiovascular implantation instrument, which is characterized by comprising the following steps:

polishing and cleaning the surface of a metal matrix material of the implantation instrument;

secondly, putting the cleaned matrix material into a vacuum chamber and carrying out pretreatment;

thirdly, Ti ions are generated in the vacuum chamber and are moved to the surface of the base material to be deposited to form a titanium transition layer;

fourthly, Ti ions and C ions are generated in the vacuum chamber at the same time, the Ti ions and the C ions are moved to the surface of the base material to be deposited, the generation ratio of the Ti ions and the C ions is gradually adjusted, and a titanium-containing gradient layer is formed;

fifthly, simultaneously generating C ions and Cu ions in the vacuum chamber, moving the C ions and the Cu ions to the surface of the base material and depositing to form the copper-containing amorphous carbon layer.

Preferably, the method comprises the following steps: the method comprises the steps of polishing a substrate material until the surface roughness Ra0.05 mu m is lower, ultrasonically cleaning the substrate material in acetone or absolute ethyl alcohol for 15-30 minutes, ultrasonically cleaning the substrate material in deionized water for 15-30 minutes, and finally drying the substrate material in a vacuum drying oven for more than 18 hours for later use.

Preferably, the method comprises the following steps: the pretreatment further comprises the following steps: placing the substrate material into a vacuum chamber with a pressure of less than 5.0 × 10^-3Pa, adjusting the flow of argon gas to make the pressure of the vacuum chamber reach 1Pa, and adjusting the bias voltage power supply to be more than 800V, thereby cleaning the surface of the metal part of the medical instrument by using the argon ion beam for at least 5 minutes.

Preferably, the method comprises the following steps: the method for obtaining the titanium transition layer further comprises the following steps: making the air pressure in the vacuum chamber less than 5.0 x 10^-3And Pa, heating the base material to 200-300 ℃, keeping the temperature, introducing argon to keep the air pressure of the vacuum chamber at 0.5-1.5 Pa, adjusting a bias voltage power supply to 300-600V, setting the sputtering current of the titanium target to be a constant value within a range of 4-6A, thereby generating Ti ions, enabling the Ti ions to move towards the base material under the action of the bias voltage, depositing for 10-20 minutes, and finally depositing a Ti transition layer on the surface of the base material.

Preferably, the method comprises the following steps: step four, the method for obtaining the titaniferous gradient layer further comprises the following steps: maintaining the air pressure and temperature in the step three, adjusting the bias power supply to 200-400V, starting the titanium target and the graphite target power supply, controlling the sputtering current of the titanium target to be gradually reduced from 3A to less than 0.2A, and the sputtering current of the graphite target to be gradually increased from 0 to 4.5A, simultaneously generating Ti ions and C ions, enabling the Ti ions and the C ions to move towards the base material under the action of bias voltage, depositing for 40-100 minutes, and finally depositing a Ti: C gradient buffer layer on the surface of the base material.

Preferably, the method comprises the following steps: step fifthly, the method for obtaining the copper-containing amorphous carbon layer further comprises the following steps: and step four, maintaining the air pressure and the temperature, turning off the power supplies of the titanium target and the graphite target, adjusting the bias power supply to 100-300V, turning on the power supplies of the copper target and the graphite target, controlling the sputtering current of the copper target to be 0.1-2A and the sputtering current of the graphite target to be 3-6A, simultaneously generating Cu ions and C ions, enabling the Cu ions and the C ions to move to the base material under the action of bias voltage, depositing for 1.5-4 hours, and finally depositing the amorphous carbon layer containing copper on the surface of the base material.

Preferably, the method comprises the following steps: step three to step fifthly, the Ti ions, the C ions and the Cu ions are all generated by a sputtering method. Compared with the prior art, the invention has the beneficial effects that:

the copper-containing composite coating provided by the invention has high hardness and wear resistance, a series of adverse effects caused by fretting wear can be greatly reduced, meanwhile, the compact DLC coating can better reduce the corrosion effect, and the phenomena of thrombus reformation and blood vessel restenosis caused by wear products and corrosion products are avoided as far as possible.

According to the preparation method of the copper-containing wear-resistant composite coating, the transition layer, the gradient buffer layer and the Cu doping design are adopted, compared with a single-layer DLC coating, the toughness and the film-substrate bonding strength are improved, the internal stress is adjusted, the phenomena of coating peeling and damage caused by the brittleness and the high internal stress of a DLC material are avoided as much as possible, and the copper-containing wear-resistant composite coating is more suitable for a cardiovascular implantation instrument adopting balloon release or self-expansion release.

The copper-containing composite coating provided by the invention has better biocompatibility. Due to the doping of the metal copper, a proper amount of copper ions can be released after the copper ions are implanted into a human body, NO signal molecules are catalytically released, and the activation of blood platelets is inhibited. In addition, excessive hemolysis is avoided, and meanwhile, endothelial cell proliferation and endothelialization are promoted, so that injury caused in the implantation process is better treated, and the risk of restenosis is further reduced.

Drawings

FIG. 1 is a schematic structural diagram of a Cu-containing composite coating according to the present invention, wherein 1 represents a base material, 2 represents a Ti transition layer, 3 represents Ti: C a Ti-containing gradient layer, and 4 represents a Cu-containing amorphous carbon layer;

FIG. 2 is a diagram showing the distance-relative content (%) curves of the three elements titanium, carbon and copper in the copper-containing composite coating according to the present invention.

Detailed Description

The following examples are further detailed below:

example 1:

referring to fig. 1, the wear-resistant coating containing copper DLC prepared on the surface of the medical nickel-titanium alloy is prepared by sequentially preparing a titanium transition layer, a titanium-containing gradient layer with a decreasing Ti to C content ratio and a Cu-DLC amorphous carbon layer from a base material, namely preparing a Ti/Ti to C/Cu-DLC composite coating.

Referring to fig. 2, the wear-resistant coating containing copper DLC prepared on the surface of the medical nickel-titanium alloy starts from a base material, and is a titanium transition layer which mainly consists of Ti; secondly, a titanium-containing gradient layer with gradually reduced Ti content and gradually increased C content; and finally, the copper-containing amorphous carbon layer contains a certain proportion of Cu.

The preparation method for preparing the copper-containing DLC wear-resistant coating on the surface of the nickel-titanium alloy of the cardiovascular implantation instrument comprises the following specific steps:

the medical nickel-titanium alloy material is polished to have the surface roughness of 0.03 mu m, ultrasonically cleaned in absolute ethyl alcohol for 15 minutes, ultrasonically cleaned in deionized water for 15 minutes, and finally dried in a vacuum drying oven for 24 hours for later use.

Secondly, the medical nickel-titanium alloy after being cleaned is pretreated, and the process is as follows: placing the base material in a vacuum chamber so that the pressure in the vacuum chamber is as low as 1.0X 10^-3Pa, regulating the flow of argon gas to enable the air pressure of the vacuum chamber to reach 1Pa, regulating the bias voltage power supply to 800V, and enabling argon ions to sputter and clean the surface of the metal part of the medical instrument for 10 minutes.

Preparing to start the cathode target in the vacuum chamber, wherein the cathode target comprises a titanium target (99.99%), a graphite target (99.99%) and a copper target (99.99%). After the argon ion cleaning, the argon gas introduction is stopped and the vacuum chamber pressure is reduced to 5.0X 10^-3And after Pa, starting a heating power supply to enable the substrate material to reach 200 ℃ and keep the temperature, then introducing argon to enable the air pressure of the vacuum chamber to be kept at 0.5Pa, adjusting a bias power supply to 300V, starting and controlling the sputtering current of a titanium target power supply to be 6A constantly, and depositing for 15 minutes to obtain the Ti transition layer with the thickness of about 300 nm.

And fourthly, adjusting the bias power supply to 300V, starting the titanium target and the graphite target power supply, controlling the sputtering current of the titanium target to gradually decrease from 3A to 0.1A and the sputtering current of the graphite target to gradually increase from 0 to 4.5A, and depositing for 75 minutes to obtain the Ti-C titanium-containing gradient layer with the thickness of about 700 nm.

And fifthly, closing the power supplies of the titanium target and the graphite target, adjusting the bias voltage power supply to 200V, opening the power supplies of the copper target and the graphite target, controlling the sputtering current of the copper target to be 0.2A, controlling the sputtering current of the graphite target to be 4.5A, and depositing for 2.5 hours to obtain the Cu-DLC amorphous carbon layer with the thickness of about 1100 nm.

The wear-resistant coating obtained by using the conditions has the total thickness of about 2.1 mu m and the thickness of the copper-containing amorphous carbon layer is about 1100 nm; the thickness of the titanium-containing gradient layer is about 700 nm; the thickness of the titanium transition layer was about 300 nm.

Through detection, the wear-resistant coating obtained by utilizing the conditions mainly contains two elements of copper and carbon, the copper content is 17 at%, and the carbon sp2 hybridization ratio is 78%. The surface nano-hardness is about 10GPa, and the surface roughness Ra is about 6 nm. The above-mentioned embodiments are only preferred embodiments of the present invention, and all equivalent changes and modifications made within the scope of the claims of the present invention should be covered by the claims of the present invention.