Carbon-based composite material skull connecting screen plate and preparation method thereof

Abstract

The invention discloses a carbon-based composite material skull connecting screen plate and a preparation method thereof, and belongs to the technical field of biomedical materials. The preparation method comprises the following steps: machining a carbon-based composite material into a skull connecting screen substrate, washing and drying the substrate, firstly performing chemical vapor deposition on a carbon or / and silicon carbide substrate, then performing physical vapor deposition on a metal film layer, and converting the metal film layer into a metal oxide layer by adopting an electrochemical oxidation method, thereby obtaining the carbon-based composite material skull connecting screen. The connecting screen plate can avoid the defects of imaging artifacts and stress shielding existing in metal materials, can enhance the adhesion, proliferation and differentiation capacity of bone cells, and can improve the biocompatibility, wear resistance and mechanical property of the bone cells at the same time.

Description

TECHNICAL FIELD

[0001] The present application relates to a skull connecting mesh plate, in particular to a carbon-based composite skull connecting mesh plate, and to a preparation method of the carbon-based composite skull connecting mesh plate, and belongs to the technical field of biomedical materials. BACKGROUND

[0002] Skull defect is one of the common sequelae of severe craniocerebral injury, cerebrovascular accident, intracranial or skull tumor after operation, often accompanied by a series of neurological symptoms of skull defect / scalp collapse syndrome. In order to restore the skull integrity, prevent brain tissue injury, maintain the stability of intracranial pressure, cerebrospinal fluid and cerebral blood flow, improve the brain function and restore the normal appearance of the patient, skullplasty is required for patients with skull defect area > 3cm 2 .

[0003] The existing skull defect repair is mostly autologous bone transplantation, fixed titanium plate / titanium mesh or PEEK mesh plate, but there are still problems such as poor fixation, stress concentration and the like in complex defects, irregular edges and thin bone areas. The skull connecting mesh plate is used to cover the skull defect with variable shape, and through specific geometric hole type, edge profile and controllable fixed assembly, better mechanical distribution and interface contact are achieved. Carbon-based composite materials such as C / C composite material and C / C / SiC composite material have good application prospect in the medical industry, which has similar elastic modulus to human bone, good toughness and plasticity, and easy processing and the like. In medical CT imaging, carbon-based composite materials are more conducive to subsequent medical diagnosis of implants than metal materials without scattering and artifacts. Non-metallic materials can greatly reduce the accumulation of heat caused by solar radiation or heating, so that the patient does not feel hot at the connecting mesh plate after the operation, and the comfort of the patient can be greatly improved. Metal titanium has good mechanical properties (high strength, high rigidity, high toughness, etc.) and biocompatibility, and is widely used in the medical field. At present, the connecting mesh plate used for skull defect repair is mostly made of titanium alloy, but pure titanium material is easy to cause stress shielding, easy to conduct heat and electricity, sensitive to external temperature difference after implantation and has artifacts in imaging detection, which is not conducive to postoperative review. The existing connecting mesh plate has a smooth surface and relies on mechanical fixation, has no biological occlusion, and is easy to cause problems such as loose fixation, which makes it difficult for bone cells to adhere, differentiate and proliferate, and it is difficult to achieve bone regeneration. SUMMARY

[0004] In view of the defects of the prior art, the first object of the present application is to provide a carbon-based composite skull connecting mesh plate, which can avoid the defects of imaging artifacts and stress shielding of metal materials, and can enhance the adhesion, proliferation and differentiation ability of bone cells, and can improve the biocompatibility, wear resistance and mechanical properties.

[0005] The second object of the present application is to provide a preparation method of the carbon-based composite material skull connecting mesh plate, which is simple in operation and low in cost, and meets the industrialized mass production.

[0006] In order to achieve the above technical objects, the present application provides a preparation method of the carbon-based composite material skull connecting mesh plate, which comprises the following steps:

[0007] 1) forming the carbon-based composite material by machining to obtain a skull connecting mesh plate substrate;

[0008] 2) after washing and drying the skull connecting mesh plate substrate, generating a carbon matrix or / and a silicon carbide matrix in the pores and on the surface thereof by chemical vapor deposition, and then generating a metal film layer on the surface thereof by physical vapor deposition to obtain a skull connecting mesh plate blank;

[0009] 3) converting the metal film layer into a metal oxide layer by electrochemical oxidation to obtain the carbon-based composite material skull connecting mesh plate.

[0010] The preparation method of the carbon-based composite material skull connecting mesh plate provided by the present application adopts a substrate machined from a carbon-based composite material, which endows the skull connecting mesh plate with light weight, good mechanical properties, and the characteristics of avoiding scattering, artifacts, stress shielding, etc. The carbon or / and silicon carbide matrix generated in the interior and on the surface of the substrate by chemical vapor deposition can further enhance the mechanical strength of the carbon-based composite material and improve its stability. The metal layer generated on the surface of the substrate can improve biocompatibility and wear resistance and avoid wear and tear of the substrate during use. However, the smooth surface of the metal layer is not conducive to the adhesion, proliferation and differentiation of bone cells, and it is difficult to achieve bone regeneration. The surface layer of the metal layer is oxidized in the present application, and the generated metal oxide can increase the roughness, adhesion and surface activity of the surface of the skull mesh plate, which is conducive to improving the adhesion, differentiation and proliferation of bone cells and improving the bone regeneration capacity. At the same time, it can further improve the hardness and wear resistance of the surface of the skull mesh plate, etc.

[0011] As a preferred scheme, the skull connecting mesh plate substrate is in a strip type, V type or X type structure, and the corners of each end are provided as rounded corners, and a connecting hole is provided. The specific structure of the skull connecting mesh plate blank of the present application is shown in Table 1, and mainly has the following different structures, such as a and b are strip type structures, c is an X type structure, and d is a V type structure, and the corners of each end are provided as rounded corners, and a sink groove is provided to reduce the protrusion of the screw. In particular, c and d (i.e. X type structure and V type structure), the included angle therebetween can be adjusted according to the angle of the skull repair sheet and the defect through the center circle, and the size of the skull connecting mesh plate blank is shown in Table 1.

[0012] ; This invention can provide various models of carbon-based composite skull connecting mesh plates according to the patient's condition. In actual use, long strip or irregular connecting mesh plates can be selected according to the skull injury area, making the selection more flexible and convenient and reducing the rate of secondary surgery.

[0013] As a preferred embodiment, the washing process is as follows: under ultrasonic assistance, anhydrous ethanol and water solvents are used sequentially at a temperature of 20-32°C for 10-15 minutes each. Ultrasonic washing primarily removes impurities or loosely bonded powder from the carbon-based composite material, which is beneficial for the subsequent chemical vapor deposition process.

[0014] As a preferred embodiment, the chemical vapor deposition (CVD) conditions are: temperature 900–1550 °C, time 8–24 h, and deposition pressure 0.6–1.5 kPa. When depositing the carbon matrix, the gas source is a hydrocarbon gas (such as natural gas, methane, or propylene). When depositing the silicon carbide matrix, the gas source is a carbon-containing silane and hydrogen gas (the flow ratio of the carbon-containing silane and hydrogen gas is preferably 1:1–10). By controlling the preferred CVD conditions, a dense carbon and / or silicon carbide matrix can be generated in the carbon-based composite material, effectively improving its mechanical properties and enhancing its stability. When depositing the carbon matrix and silicon carbide matrix, a method of depositing a portion of the carbon matrix first, followed by a portion of the silicon carbide matrix, or vice versa, can be used.

[0015] As a preferred embodiment, the metal film layer includes a titanium film layer, a strontium film layer, a zinc film layer, or a tantalum film layer. Compared to other metals, the present invention prefers metals such as titanium, strontium, zinc, and tantalum. On the one hand, these metals have good biocompatibility; on the other hand, the oxides of these metals can promote bone integration and enhance connection stability.

[0016] As a preferred embodiment, the physical vapor deposition conditions are: Ar gas flow rate of 60~230 sccm, and vacuum degree of 3.1×10⁻⁶. -1 ~5.6×10 -1 The deposition conditions are as follows: Pa, metal target power 0.4–3.6 kW, ion source power 0.6–2.8 kW, workpiece negative bias voltage 100–800 V, duty cycle 40–60%, and deposition time 60–480 min. Further optimized, when the deposited metal film is a titanium film, the deposition conditions are: Ar gas flow rate 90–220 sccm, vacuum degree 3.5 × 10⁻⁶. -1 ~4.5×10 -1The deposition conditions were as follows: Pa, Ti target power 0.4–3 kW, ion source power 0.9–2.3 kW, workpiece negative bias voltage 100–800 V, duty cycle 40–60%, and deposition time 60–360 min. When the deposited metal film was a strontium film, the deposition conditions were: Ar gas flow rate 80–200 sccm, vacuum degree 3.8 × 10⁻⁶. -1 ~4.9×10 -1 The Sr target power is 0.4–3.5 kW, the ion source power is 0.8–2.6 kW, the workpiece negative bias voltage is 100–600 V, the duty cycle is 40–60%, and the deposition time is 60–450 min. When the deposited metal film is a zinc film, the deposition conditions are: Ar gas flow rate is 60–210 sccm, and the vacuum degree is 3.3 × 10⁻⁶. -1 ~5.4×10 -1 The Zn target power is 0.6–3.6 kW, the ion source power is 0.6–2.8 kW, the workpiece negative bias voltage is 100–700 V, the duty cycle is 40–60%, and the deposition time is 60–420 min. When the deposited metal film is a tantalum film, the deposition conditions are: Ar gas flow rate is 100–220 sccm, and the vacuum degree is 3.8 × 10⁻⁶. -1 ~5.6×10 -1 The target power is 0.7~3.5kW, the ion source power is 0.8~2.8kW, the workpiece negative bias voltage is 100~800V, the duty cycle is 40~60%, and the deposition time is 60~480min. Under the preferred physical vapor deposition conditions, a uniform metal film of a certain thickness can be formed on the surface of the skull connecting mesh plate blank.

[0017] As a preferred embodiment, the electrochemical oxidation process is as follows: using a skull connecting mesh plate blank as the anode and an inert metal as the cathode, setting the distance between the anode and cathode to 15-30 mm, using ammonium fluoride solution or sulfuric acid solution as the electrolyte solution, and passing an electric current to perform electrochemical oxidation. As a more preferred embodiment, the solvent medium in the ammonium fluoride solution is composed of ethylene glycol and water in a volume ratio of 85-95%:5-15%, with an ammonium fluoride (NH4F) concentration of 0.1-1 wt%; the sulfuric acid concentration in the sulfuric acid solution is 0.3-0.8 mol / L. As a more preferred embodiment, the electrochemical oxidation conditions are: temperature 5-40℃, voltage 20-40V, and time 15-60 min. As a more preferred embodiment, the distance between the anode and cathode is further preferably 20 mm. The key to the electrochemical oxidation process is controlling the temperature, voltage, and time conditions, which is beneficial for the oxidation of the metal coating to form a dense, rough, and porous metal oxide layer. Excessive temperature reduces the density of the metal oxide layer and causes uneven pore structure, while increasing internal stress and the risk of stress cracking. Excessive voltage easily generates stress and cracks, while insufficient voltage slows the growth of the metal oxide layer. Longer electrochemical oxidation times result in thicker films, but excessive time increases the risk of interlayer delamination and increased mechanical stress. The distance between electrodes affects the electric field strength; too close a distance can lead to localized overheating or short circuits, and also results in excessively strong electric fields, causing localized stress concentration and increasing the risk of cracking and interlayer delamination. Platinum is a commonly preferred inert metal. The preferred current is direct current or pulsed current, with direct current being the most preferred. The cranial mesh plate blank acts as the anode. During electrolysis, the cranial mesh plate blank is oxidized by oxygen released from the anode, causing the metal film layer on its surface to oxidize. Under preferred electrochemical oxidation conditions, this results in the formation of a dense, rough metal oxide layer on the mesh plate blank. The metal oxide layer improves the surface hardness and wear resistance of the cranial mesh plate, and also increases surface roughness, adhesion, and surface activity.

[0018] The present invention also provides a carbon-based composite cranial connecting mesh plate, which is obtained by the preparation method described above.

[0019] The carbon-based composite cranial mesh plate provided by this invention is made of carbon-based composite material, which has the characteristics of being lightweight, having good mechanical properties, avoiding scattering and artifacts, and stress shielding. A dense, rough, and bioactive metal oxide layer is generated in situ on its surface, which can increase the roughness, adhesion and surface activity of the cranial mesh plate surface, which is beneficial to improving bone cell adhesion, differentiation and proliferation, and improving bone regeneration capacity. At the same time, it can further improve the hardness and wear resistance of the cranial mesh plate surface.

[0020] Compared with existing technologies, the beneficial technical effects of the present invention are as follows:

[0021] The carbon-based composite cranial linker plate of this invention is composed of carbon-based composite materials, which can avoid the technical defects of conventional metal materials, such as imaging artifacts and stress masking. Furthermore, its surface has a special metal oxide layer that enhances bone cell adhesion, proliferation, and differentiation, thereby improving its biocompatibility, wear resistance, and mechanical properties. Animal experiments (referring to GB / T16886.6-2020) showed that 4 weeks after implantation, the bone volume fraction was 30.2~33.7 BV / TV (%), the trabecular bone thickness reached 0.44~0.64 Tb.Th (mm), the number of trabecular bone reached 0.96~1.15 Tb.N (1 / mm), the hardness reached 16.0~28.0 GPa, the maximum tensile load reached 240~275 N, and the coefficient of friction decreased to 0.10~0.20.

[0022] The preparation method of the carbon-based composite cranial connecting mesh plate of the present invention is simple to operate, low in cost, and meets the requirements for industrial mass production. Attached Figure Description

[0023] Figure 1 To test the mechanical properties of cranial mesh plates with the same size and morphology prepared from three different materials—pure titanium, PEEK, and C / C composite material—under the same conditions, (a) is a pure titanium cranial mesh plate; (b) is a PEEK cranial mesh plate; and (c) is a C / C composite cranial mesh plate.

[0024] Figure 2 The image shows the morphology of the C / C composite cranial connecting mesh plate containing a ZnO layer prepared in Example 2; where A is the surface morphology and B is the cross-sectional morphology of the oxide layer.

[0025] Figure 3 The images show partial samples of the C / C composite skull connecting mesh plates containing ZnO layers prepared in Example 2 and Comparative Example 1; where (a) is the sample of Example 2 and (b) is the sample of Comparative Example 1.

[0026] Figure 4 The images show the morphology of the C / C composite cranial connecting mesh plate containing a TiO2 layer prepared in Example 3; where (a) is a microscopic morphology image and (b) is a macroscopic physical image. Detailed Implementation

[0027] To make the present invention clearer, specific embodiments will be described in detail below. The specific embodiments described herein are for illustrative purposes only and do not limit the scope of the invention.

[0028] Example 1

[0029] To prepare a C / C composite cranial connecting mesh plate containing a TiO2 layer, follow these steps:

[0030] A. Machining: The C / C composite material is processed into a long strip-shaped skull connecting mesh plate with dimensions of 20mm in length, 7mm in width, and 1.6mm in thickness. The sphere radius of the rounded corners at both ends is 2.5mm, and the sinker design radius is 0.3mm. This results in the C / C composite skull connecting mesh plate matrix.

[0031] B. Cleaning the C / C composite cranial connector mesh substrate. Cleaning steps: The C / C composite cranial connector mesh substrate is ultrasonically cleaned with anhydrous ethanol and deionized water, respectively. The cleaning temperature is 28℃ and the cleaning time is 10min. After cleaning, it is dried and ready for use.

[0032] C. The C / C composite cranial splint substrate, after ultrasonic treatment of the medium, was subjected to carbon deposition via chemical vapor deposition to obtain a C / C composite cranial splint blank. The conditions for chemical vapor deposition of the carbon substrate were: deposition temperature of 1350℃, deposition time of 10 h, deposition pressure of 1.2 kPa, and methane as the gas source.

[0033] D. Place the C / C composite skull connecting mesh blank after chemical vapor deposition treatment in a physical vapor deposition coating equipment and evacuate to the working vacuum level.

[0034] E. Removing impurities from the furnace: Ar gas is introduced into the vacuum chamber at a flow rate of 120 sccm, with a vacuum level of 3.6 × 10⁻⁶. -1 Pa, the workpiece negative bias voltage is 800V, and the degassing time is 20min.

[0035] F. Ion source cleaning of workpiece: Ar gas flow rate is 80 sccm, vacuum degree is 3.8 × 10⁻⁶ -1 Pa, ion source power is 1kW, workpiece negative bias voltage is 800V, cleaning time is 30min.

[0036] G. Preparation of Ti transition layer: Ar gas flow rate is 120 sccm, vacuum degree is 4.0 × 10⁻⁶ -1 The target power of Pa and Ti was 2.2 kW, the ion source power was 1.3 kW, the workpiece negative bias voltage was 200 V, the duty cycle was 50%, and the deposition time was 240 min.

[0037] H. Once the coating equipment has cooled to room temperature, the C / C composite cranial connector blank containing the Ti coating is removed and subjected to anodizing. The anode is the cranial connector blank, and the cathode is a platinum plate (0.5×0.5×0.1mm). The distance between the electrodes is 20mm. Ammonium fluoride solution (0.8wt% NH4F, solvent medium of 90% vol ethylene glycol solution and 10 vol% deionized water) is selected as the electrolyte. At room temperature, the voltage is set to 25V, and the reaction time is 40min, resulting in a C / C composite cranial connector plate containing a TiO2 oxide layer.

[0038] The obtained C / C composite cranial connector plate samples containing TiO2 layers underwent animal testing in accordance with Part II: Experimental Design, Implementation, and Quality Assurance of the Guidelines for Registration and Review of Animal Testing Research for Medical Devices. Healthy male and female beagles, randomly selected for 12 months of age and weighing 10±2 kg, were used in the experiment. A control experiment was conducted using pure titanium samples, following GB / T16886.6-2020. Four weeks after implantation, the formation of trabecular bone was observed through hard tissue pathological sections. The specific experimental steps are as follows: ① Dehydration: After fixing the specimen in formalin for 48 hours, rinse with running water for 24 hours, and then perform ascending dehydration with progressively stronger alcohol (70%~90%) (24 hours per step). Soak in anhydrous alcohol + Technovit 7200 resin solution (3:7) for 2 days, then soak in anhydrous alcohol + Technovit 7200 resin solution (1:1) for 2 days, then soak in Technovit 7200 resin solution I for 7 days, and then soak in Technovit 7200 resin solution II for 3 days; ② Embedding: Embed and polymerize in a light-curing machine. Remove the tissue block; ③ Sectioning: Cut 200μm sections from the tissue using a hard tissue microtome, and grind the sections to 25μm using a grinding mill with 320-mesh, 800-mesh, and 1200-mesh sandpaper. Finally, polish with 4000-mesh sandpaper; ④ Methylene blue and acid fuchsin staining: Stain with methylene blue staining solution, bathe in a 60℃ water bath for 15 minutes, and blot dry with filter paper. Rinse with 60℃ distilled water for 1 min and dry. Stain with acidic fuchsin solution for 5 min, then blot dry with filter paper. Dehydrate with 95% ethanol and anhydrous ethanol respectively. Clear with xylene and seal with optical resin.

[0039] The results of methylene blue and acid fuchsin staining of the samples showed that the experimental group had a bone volume fraction of 32.6 BV / TV (%), a trabecular bone thickness of 0.61 Tb.Th (mm), and a trabecular bone number of 1.11 Tb.N (1 / mm). The control group had a bone volume fraction of 33.8 BV / TV (%), a trabecular bone thickness of 0.73 Tb.Th (mm), and a trabecular bone number of 0.81 Tb.N (1 / mm). The experimental group had 37% more trabecular bone than the control group. The hardness reached 23.2 GPa, the coefficient of friction was 0.13, the endothelial cell proliferation rate increased by 4%, the oxide layer surface was dense, the thickness reached 1.56 μm, and the bonding force was good.

[0040] ; Mechanical properties of cranial mesh plates of the same size and morphology prepared from three different materials—pure titanium, PEEK, and C / C composite material—were tested under the same conditions. Figure 1 As shown; (a) is a pure titanium cranial mesh plate; (b) is a PEEK cranial mesh plate; (c) is a C / C composite cranial mesh plate, indicating that the mechanical properties of the C / C composite cranial mesh plate containing a TiO2 layer are close to those of the titanium metal cranial mesh plate and better than those of the PEEK cranial mesh plate.

[0041] Example 2

[0042] To prepare a C / C composite cranial connector plate containing a ZnO layer, follow these steps:

[0043] A. Machining: The C / C composite material is machined into a V-shaped structure with a length of 22mm (single side length), a width of 4mm, a thickness of 1.8mm, an included angle of 60°, a corner radius of 2.5mm, and a groove design radius of 0.3mm to form a skull connecting mesh plate, thus obtaining the C / C composite skull connecting mesh plate matrix.

[0044] B. Cleaning the C / C composite cranial connector mesh substrate. Cleaning steps: The C / C composite cranial connector mesh substrate is ultrasonically cleaned with anhydrous ethanol and deionized water, respectively. The cleaning temperature is 28℃ and the cleaning time is 10min. After cleaning, it is dried and ready for use.

[0045] C. The C / C composite skull connector mesh substrate, after ultrasonic treatment of the medium, is subjected to carbon deposition via chemical vapor deposition to obtain a C / C composite skull connector mesh blank. The conditions for chemical vapor deposition of the carbon substrate are: deposition temperature of 1450℃, deposition time of 12h, deposition pressure of 1.3kPa, and methane as the gas source.

[0046] D. Place the C / C composite skull connecting mesh blank after chemical vapor deposition treatment in a physical vapor deposition coating equipment and evacuate to the working vacuum level.

[0047] E. Remove impurities from the furnace: Introduce Ar gas into the vacuum chamber at a flow rate of 100 sccm, maintaining a vacuum level of 3.5 × 10⁻⁶. -1 Pa, the workpiece negative bias voltage is 600V, and the degassing time is 20min.

[0048] F. Ion source cleaning of workpiece: Ar gas flow rate is 120 sccm, vacuum degree is 3.8 × 10⁻⁶ -1 Pa, ion source power of 1.2kW, workpiece negative bias voltage of 600V, cleaning time of 30min.

[0049] G. Preparation of Zn transition layer: Ar gas flow rate is 120 sccm, vacuum degree is 4.0 × 10⁻⁶ -1 The target power of Pa and Zn is 2.4kW, the ion source power is 1.2kW, the workpiece negative bias voltage is 200V, the duty cycle is 50%, and the deposition time is 300min.

[0050] H. Once the coating equipment has cooled to room temperature, remove the Zn-coated C / C composite cranial connector blank and perform anodizing. The anode is the cranial connector blank, and the cathode is a platinum plate (0.5 × 0.5 × 0.1 mm). The distance between the electrodes is 20 mm. An ammonium fluoride solution (0.5 wt% NH4F, with 90% vol ethylene glycol solution and 10 vol% deionized water as the electrolyte) is selected. At room temperature, the voltage is set to 20 V, and the reaction time is 30 min to obtain a ZnO-coated C / C composite cranial connector plate.

[0051] Animal experiments on C / C composite skull connector plates containing ZnO layers were conducted according to Example 1. The experimental results are as follows:

[0052] The results of methylene blue and acid fuchsin staining of the samples showed the following: the bone volume fraction in the experimental group was 32.8 BV / TV (%), the trabecular bone thickness reached 0.64 Tb.Th (mm), the number of trabecular bone reached 1.09 Tb.N (1 / mm), the hardness reached 22.4 GPa, the maximum tensile load was 262 N, and the coefficient of friction was 0.20. In this example, the endothelial cell proliferation rate of the C / C composite cranial fixation plate containing a ZnO layer was increased by 7%. Compared with the PEEK cranial fixation plate, it has higher hardness and enhanced connection stability with bone tissue, resulting in more secure fixation.

[0053] Morphological image of the C / C composite cranial connection mesh plate containing a ZnO layer is shown below. Figure 2As shown in the figure; where A is the surface morphology diagram and B is the cross-sectional morphology of the oxide layer, it can be seen that the surface is relatively dense and has a porous structure, and the surface is rough.

[0054] Comparative Example 1

[0055] The only difference compared to Example 2 is that the voltage is set to 50V.

[0056] The C / C composite skull bonding mesh sample with ZnO oxide layer prepared in Comparative Example 1 exhibited surface cracks and interlayer delamination due to excessive electric field strength causing localized stress concentration. Specifically, as shown in... Figure 3 As shown in (b) (partial sample), the effect is worse than the C / C composite skull connection mesh sample with ZnO layer prepared in Example 2, specifically as follows: Figure 3 As shown in (a) (local sample).

[0057] Comparative Example 2

[0058] The only difference compared to Example 2 is that the electrochemical oxidation time is 120 min.

[0059] The C / C composite skull bonding mesh sample with ZnO layer prepared in Comparative Example 2 showed interlayer delamination due to excessive electrochemical oxidation time, over-oxidation of the zinc coating, increased internal stress.

[0060] Example 3

[0061] To prepare a C / C composite cranial connecting mesh plate containing a TiO2 layer, follow these steps:

[0062] A. Machining: The C / C composite material is machined into an X-shaped skull connecting mesh substrate with a length of 26mm, a width of 3mm, a thickness of 1.8mm, a central circle radius of 2mm, a circle radius of 2.5mm, a groove design radius of 0.3mm, and an angle of 20°, thus obtaining the C / C material skull connecting mesh substrate.

[0063] B. Cleaning the C / C composite cranial connector mesh substrate. Cleaning steps: The C / C composite cranial connector mesh substrate is ultrasonically cleaned with anhydrous ethanol and deionized water, respectively. The cleaning temperature is 28℃ and the cleaning time is 10min. After cleaning, it is dried and ready for use.

[0064] C. The C / C composite cranial splint substrate, after ultrasonic treatment of the medium, was subjected to carbon deposition via chemical vapor deposition to obtain a C / C composite cranial splint blank. The conditions for chemical vapor deposition of the carbon substrate were: deposition temperature of 1300℃, deposition time of 9 h, deposition pressure of 1.3 kPa, and methane as the gas source.

[0065] D. Place the C / C composite skull connecting mesh blank after chemical vapor deposition treatment in a physical vapor deposition coating equipment and evacuate it to the working vacuum level.

[0066] E. Removing impurities from the furnace: Ar gas is introduced into the vacuum chamber at a flow rate of 110 sccm, with a vacuum level of 3.7 × 10⁻⁶. -1 Pa, the workpiece negative bias voltage is 700V, and the degassing time is 20min.

[0067] F. Ion source cleaning of workpieces: Ar gas flow rate 100 sccm, vacuum degree 3.9 × 10⁻⁶ -1 Pa, ion source power of 1.1kW, workpiece negative bias voltage of 700V, cleaning time of 30min.

[0068] G. Preparation of the Ti transition layer: Ar gas flow rate was 130 sccm, and vacuum degree was 4.0 × 10⁻⁶. -1 The Pa, Ti target power is 2.6kW, the ion source power is 1.1kW, the workpiece negative bias voltage is 400V, the duty cycle is 60%, and the deposition time is 330min.

[0069] H. After the coating equipment cools to room temperature, the C / C composite cranial connector plate blank containing the Ti coating is removed and subjected to anodizing treatment. The anode is the cranial connector plate blank, and the cathode is a platinum plate (0.5×0.5×0.1mm). The distance between the electrodes is 21mm, and ammonium fluoride solution (0.6wt% NH4F, solvent medium is 90% vol ethylene glycol solution and 10 vol% deionized water) is selected as the electrolyte. At room temperature, the voltage is set to 24V, and the reaction time is 40min to obtain the C / C composite cranial connector plate containing the TiO2 layer.

[0070] The C / C composite cranial mesh plate containing a TiO2 layer prepared in this embodiment exhibits good biocompatibility, no powder shedding, a membrane bonding strength of 22 N, a hardness of 18.1 GPa, a friction coefficient of 0.17, and a 7% increase in endothelial cell proliferation rate. Animal experiments, referring to Example 1, showed that the experimental group had a bone volume fraction of 32.5 BV / TV (%), a trabecular bone thickness of 0.58 Tb.Th (mm), and a trabecular bone number of 1.01 Tb.N (1 / mm). Compared with pure titanium cranial mesh plates, it has comparable tensile strength, exhibits no artifacts on X-ray transmission, clear imaging, and a porous surface structure that facilitates tissue ingrowth, enhancing fixation effectiveness. It can also reduce heat accumulation caused by solar radiation or heating, preventing patients from experiencing heat or burning at the mesh plate connection point postoperatively, thus greatly improving patient comfort.

[0071] Morphology of the C / C composite cranial connector plate containing a TiO2 layer is shown in the figure below. Figure 4As shown; (a) is a microscopic morphology diagram and (b) is a macroscopic physical image. It can be seen that its surface is relatively dense and has a porous structure, and the surface is rough.

Claims

1. A method for preparing a carbon-based composite cranial connecting mesh plate, characterized in that: Includes the following steps: 1) The carbon-based composite material is machined to obtain the skull connection mesh matrix; 2) After washing and drying, the skull connecting mesh plate substrate is first subjected to chemical vapor deposition to generate carbon and / or silicon carbide substrate in its pores and on its surface, and then subjected to physical vapor deposition to generate metal film layer on its surface to obtain skull connecting mesh plate blank. 3) The skull connecting mesh plate blank is electrochemically oxidized to transform the metal film layer into a metal oxide layer, thus obtaining a carbon-based composite skull connecting mesh plate.

2. The method for preparing a carbon-based composite cranial connecting mesh plate according to claim 1, characterized in that: The skull connecting mesh plate substrate has a strip, V-shaped, or X-shaped structure, and the corners of each end are rounded, and it is also provided with connecting holes.

3. The method for preparing a carbon-based composite cranial connecting mesh plate according to claim 1, characterized in that: The washing process is as follows: under ultrasonic assistance, anhydrous ethanol solvent and water solvent are used sequentially at a temperature of 20~32℃ for 10~15 minutes respectively.

4. The method for preparing a carbon-based composite cranial connecting mesh plate according to claim 1, characterized in that: The conditions for chemical vapor deposition are: temperature of 900~1550℃, time of 8~24 h, deposition pressure of 0.6~1.5 kPa. When depositing carbon substrate, the gas source is hydrocarbon gas, and when depositing silicon carbide substrate, the gas source is carbon-containing silane and hydrogen.

5. The method for preparing a carbon-based composite cranial connecting mesh plate according to claim 1, characterized in that: The metal film layer includes a titanium film layer, a strontium film layer, a zinc film layer, or a tantalum film layer.

6. A method for preparing a carbon-based composite cranial connecting mesh plate according to claim 1 or 5, characterized in that: The physical vapor deposition conditions were: Ar gas flow rate of 60~230 sccm, and vacuum degree of 3.1×10⁻⁶. -1 ~5.6×10 - 1 Pa, metal target power of 0.4~3.6kW, ion source power of 0.6~2.8kW, workpiece negative bias voltage of 100~800V, duty cycle of 40~60%, deposition time of 60~480min.

7. The method for preparing a carbon-based composite cranial connecting mesh plate according to claim 1, characterized in that: The electrochemical oxidation process is as follows: using the skull connecting mesh plate blank as the anode and an inert metal as the cathode, setting the distance between the anode and the cathode to be 15~30mm, using ammonium fluoride solution or sulfuric acid solution as the electrolyte solution, and passing an electric current to carry out electrochemical oxidation.

8. The method for preparing a carbon-based composite cranial connecting mesh plate according to claim 7, characterized in that: The solvent medium in the ammonium fluoride solution is composed of ethylene glycol and water in a volume ratio of 85-95%:5-15%, and the concentration of ammonium fluoride is 0.1-1 wt%. The sulfuric acid concentration in the sulfuric acid solution is 0.3~0.8 mol / L.

9. The method for preparing a carbon-based composite cranial connecting mesh plate according to claim 6, characterized in that: The conditions for the electrochemical oxidation are: temperature 5~40℃, voltage 20~40V, and time 15~60min.

10. A carbon-based composite cranial connecting mesh plate, characterized in that: It is obtained by the preparation method according to any one of claims 1 to 9.

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