A carbon-based lung nodule localization needle and its preparation method

Abstract

This invention discloses a carbon-based lung nodule localization needle and its preparation method. The localization needle uses a carbon-based material as a substrate, on which a pyrolytic carbon (PyC) coating and a silver-doped DLC (DLC) composite coating are prepared. The PyC coating provides a continuous interface to improve the bonding ability between the silver-doped DLC composite coating and the carbon-based material. The silver-doped DLC composite coating effectively reduces the surface friction coefficient of the carbon-based material, improving its wear resistance and hardness. It also mitigates adverse reactions in the human body caused by frictional powdering of the carbon-based material after implantation. Furthermore, the silver-doped DLC coating imparts good surface biocompatibility and antibacterial properties to the carbon-based material. In particular, the silver-doped DLC composite coating exhibits high bonding strength and good stability with the carbon-based material surface, extending its service life.

Description

Technical Field

[0001] This invention relates to a carbon-based lung nodule positioning needle, particularly to a lung nodule positioning needle made of carbon-based material with a PyC coating and a silver-doped DLC composite coating on its surface, and also to its preparation method, belonging to the field of biomedical materials technology. Background Technology

[0002] Currently, the incidence and mortality rates of lung cancer are increasing year by year. Because early-stage lung cancer is insidious and difficult to detect, 80% of lung cancers discovered clinically are already in the middle or late stages. Therefore, lung cancer has become the leading cause of death from malignant tumors. The five-year survival rate for lung cancer is only 15%, while the five-year survival rate for early-stage lung cancer treated promptly can reach 60-80%. With the widespread use of low-dose spiral CT lung cancer screening, more and more pulmonary nodules are being detected. Pulmonary nodules are small, focal, round or oval shadows with increased density on imaging. They can be single or multiple, without atelectasis, hilar enlargement, or pleural effusion. Solitary pulmonary nodules are asymptomatic and are often single, well-defined, high-density soft tissue shadows ≤3cm in diameter, surrounded by air-containing lung tissue.

[0003] With endoscopic thoracoscopic surgery (VATS) becoming the primary method for the diagnosis and treatment of pulmonary nodules, small pulmonary nodules, characterized by their small size, low solid content, and soft texture, cannot be accurately located during VATS using observation or palpation. Even for pulmonary nodules ≤1cm in size after conversion to open thoracotomy, the failure rate for localization using visual observation and palpation methods exceeds 50%. Therefore, in clinical practice, CT-guided precise localization of small pulmonary nodules is often performed preoperatively to increase the accuracy of pulmonary nodule resection, achieve minimal wedge resection, reduce surgical trauma, and improve the patient's quality of life.

[0004] Common localization methods include the following technical routes: 1) Staining agent: puncture under CT guidance before surgery, and inject methylene blue around the nodule for color marking; 2) Medical colloid: puncture under CT guidance before surgery, and inject N-butyl-2-cyanoacrylate around the nodule to rapidly solidify into a colloidal substance, and locate the nodule by the mass formed by the colloidal substance; 3) Indwelling positioning needle: puncture under CT guidance before surgery, and place a positioning needle around the nodule for localization.

[0005] Staining agents were widely used in clinical practice in the early days, but due to their rapid staining and diffusion, strict requirements on the surgical interval after staining, and low intraoperative color recognition in patients with significant carbon deposition, they are prone to localization failure. Medical colloids have an irritating odor, can cause significant irritating cough after entering the bronchi, and sometimes coagulate in the injection syringe. Therefore, the indwelling positioning needle wire technique is currently the most widely used extracorporeal localization technique for pulmonary micronodules and intrapulmonary ground-glass opacities. These mainly include nickel-titanium alloy microcoils, four-hook positioning needles, unique dumbbell-shaped coils, and stainless steel hooked metal guidewires. However, this technique also has certain shortcomings. Patients often experience pain and pleural irritation after localization; sometimes, delayed surgery, time, and movement can increase the risk of displacement, dislodgement, or even breakage. Furthermore, common complications such as pneumothorax, bleeding, and pain are prone to occur after localization. Moreover, when a positioning needle is placed under ventilation, the lung collapse and changes in lung volume may further damage the lung. Furthermore, the ends of the metal wires are prone to breakage and remain inside the body. Because the metal wires are very small and difficult to find, if they break and are not treated promptly and effectively, it may lead to a major medical accident of residual metal objects in the lungs after surgery.

[0006] Carbon-based materials are excellent biomaterials, but they are brittle, and their local brittleness is particularly pronounced when used to manufacture small parts. Positioning pins made from them are prone to falling off and causing secondary damage. In addition, although carbon-based materials are inert, their porous nature makes them prone to carrying bacteria into human tissues during use, which can lead to inflammation. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the first objective of this invention is to provide a carbon-based lung nodule positioning needle. The key to this needle is the deposition of a PyC coating and a silver-doped DLC composite coating on its surface. This effectively solves the technical problems existing in the preparation of lung nodule positioning needles from carbon-based materials. The silver-doped DLC composite coating not only effectively reduces the surface friction coefficient of the carbon-based material, improving its wear resistance and hardness, but also mitigates adverse reactions in the human body caused by frictional powdering after implantation. Furthermore, the silver-doped DLC composite coating endows the carbon-based material with excellent surface biocompatibility and antibacterial and bactericidal properties. In particular, the silver-doped DLC composite coating exhibits high adhesion and good stability to the carbon-based material surface, extending its service life.

[0008] Another objective of this invention is to provide a method for preparing a carbon-based material lung nodule positioning needle, which is simple to operate, easy to control precisely, and conducive to industrial production.

[0009] To achieve the above-mentioned technical objectives, the present invention provides a carbon-based lung nodule positioning needle, including an insertable needle or an embedded needle; the insertable needle includes a needle bar with a conical tip at the front end and a pin at the rear end, and the needle bar or pin is provided with a lead hole; the embedded needle includes a needle bar with a conical tip or a blunt tip at the front end and a pin at the rear end, and the pin is provided with a lead hole; the lung nodule positioning needle is composed of a carbon-based material and a PyC coating and a silver-doped DLC composite coating on its surface.

[0010] The lung nodule positioning needle of this invention, coated with a PyC coating and a silver-doped DLC composite coating, effectively solves the defects of carbon-based materials in the fabrication of small-sized parts, such as local brittleness, easy powder shedding leading to secondary damage, and the tendency of carbon-based materials to carry bacteria into human tissues during use, causing inflammation. The PyC coating is mainly deposited on the surface of the carbon-based material substrate, sealing the surface pores and providing a continuous interface that enhances its surface resistance to breakage. It also improves the adhesion between the PyC coating and the silver-doped DLC composite coating. The silver-doped DLC composite coating has good biocompatibility, surface hardness, and friction properties, and also possesses antibacterial properties. Compared to existing DLC ​​coatings, the introduction of metallic silver effectively improves the overall performance of the DLC coating, such as improving its biocompatibility, friction properties, and hardness. Furthermore, the overlapping deposition of the silicon transition layer and the silver-doped DLC coating allows the silver elements incorporated into the DLC coating to bond more tightly with the atoms in the silicon transition layer, reducing the internal stress of the entire composite coating and significantly improving the adhesion between the composite coating and the carbon-based material substrate. Furthermore, depositing a silver-doped DLC composite coating on the surface of the carbon-based lung nodule positioning needle can prevent adverse reactions in the human body caused by friction and powder shedding after the carbon-based lung nodule positioning needle is implanted.

[0011] As a preferred embodiment, the silver-doped DLC composite coating is composed of n layers of silicon transition film and n layers of silicon-doped DLC film, which are alternately stacked; where n = 2 to 10. If there are too few film layers, it will be difficult to improve the wear resistance and hardness of the carbon-based material surface; if there are too many film layers, it will reduce the bonding ability between the composite coating and the carbon-based material substrate, making the coating easier to peel off.

[0012] As a preferred embodiment, the silver doping amount in each silver-doped DLC film layer of the silver-doped DLC composite coating decreases gradually from the inner layer to the outer layer. Decreasing the silver doping amount from the inner to the outer layer in each silver-doped DLC film layer can effectively improve the adhesion between the entire composite coating and the carbon-based substrate, while also better enhancing the biocompatibility of the outermost silver-doped DLC film layer.

[0013] As a preferred embodiment, the PyC coating thickness is 10–50 μm. If the PyC coating is too thin, it cannot form a complete, continuous coating; if the coating is too thick, the surface roughness increases, and it is prone to peeling off.

[0014] As a preferred embodiment, the thickness of the silicon transition layer is 0.1–1.5 μm.

[0015] As a preferred embodiment, the thickness of the silver-doped DLC film is 0.3–3.5 μm. If the silicon transition film thickness is too low or the silver-doped DLC film thickness is too high, the bonding ability between the silver-doped DLC film and the carbon-based material will be reduced. Conversely, if the silicon transition film thickness is too high or the silver-doped DLC film thickness is too low, the hardness and wear resistance will be reduced.

[0016] As a preferred embodiment, the silver content in the silver-doped DLC composite coating is 1% to 20% by mass, and the silver content in the outermost silver-doped DLC film layer is no higher than 10% by mass. Increasing the silver doping amount within an appropriate range can effectively improve the bonding force between the composite coating and the carbon-based material. However, when the silver content in the outermost silver-doped DLC film layer exceeds 10% by mass, its biocompatibility will decrease and it may poison normal cells. Therefore, the silver content of the entire silver-doped DLC composite coating and the surface silver-doped DLC film layer should be controlled within an appropriate range.

[0017] As a preferred embodiment, the diameter of the needle bar is 1.5–2 mm; the diameter of the pin bar is 1.0–1.5 mm; the diameter of the lead hole is 0.2–0.5 mm; and the taper of the cone tip is >30°.

[0018] The present invention also provides a method for preparing a carbon-based material lung nodule positioning needle. The method involves forming a needle blank by machining the carbon-based material, depositing a PyC coating on the surface of the blank, and then depositing a silver-doped DLC composite coating to obtain the needle.

[0019] As a preferred embodiment, the PyC coating is generated by chemical vapor deposition (CVD), wherein the CVD conditions are: deposition at 1000–1800°C for 10–50 hours under the condition of introducing a gaseous carbon source. The gaseous carbon source is a common hydrocarbon gas, such as methane, propane, etc.

[0020] As a preferred embodiment, the silver-doped DLC composite coating is deposited by a combination of unbalanced intermediate frequency magnetron sputtering and DC arc PECVD. First, a silicon transition film is deposited by unbalanced intermediate frequency magnetron sputtering, and then a silver-doped DLC film is deposited by a combination of unbalanced intermediate frequency magnetron sputtering and DC arc PECVD, and the deposition is performed alternately.

[0021] As a preferred embodiment, the deposition conditions for the silicon transition film are: Ar gas flow rate of 60–100 sccm, silicon target power of 0.5–3 kW, and vacuum degree of 1.0 × 10⁻⁴. 1 ~4.0×10- 1 The temperature ranges from 0.5 to 2 kW, the ion source power is 0.5 to 2 kW, the workpiece negative bias voltage is 50 to 400 V, and the deposition time is 10 to 80 min. Unbalanced magnetron sputtering can control the temperature below 200 °C during silicon film preparation, resulting in a denser film that improves the bonding between the deposited film and the substrate.

[0022] As a preferred embodiment, the deposition conditions for the silver-doped DLC film are: Ar gas flow rate of 20–100 sccm, gas carbon source flow rate of 10–100 sccm, and vacuum degree of 1.0 × 10⁻⁴. 1 ~4.0×10- 1 The process involves using a combination of unbalanced mid-frequency magnetron sputtering and DC arc PECVD to deposit silver-doped DLC films. The ion source power is 0.5–3 kW, the silver-palladium power is 0.1–1 kW, the silver target purity is not less than 99.9 wt%, the workpiece negative bias voltage is 50–600 V, and the deposition time is 30–540 min. Furthermore, during the deposition of any two adjacent silver-doped DLC films, the silver target power for depositing the outer silver-doped DLC film decreases by 0.1–0.3 kW compared to the inner silver-doped DLC film. This invention utilizes a combination of unbalanced mid-frequency magnetron sputtering and DC arc PECVD to deposit silver-doped DLC films. This allows for better control of the silver content without altering the DLC film preparation process parameters, stably maintaining the silver mass percentage within the most effective range of 1%–15% for improving film performance. Gaseous carbon sources such as acetylene are also used.

[0023] The carbon-based material of the present invention is prepared by existing conventional methods, as illustrated below:

[0024] 1) A carbon fiber preform is formed by needle punching a laminate of wide-bundle carbon fiber and carbon fiber mesh, wherein the carbon fiber is a 3mm wide 1k carbon fiber bundle, a 5mm wide 2k carbon fiber bundle, an 8mm wide 3k carbon fiber bundle, a 15mm wide 6k carbon fiber bundle, or a 25mm wide 12k carbon fiber, or a combination thereof; the carbon fiber mesh has a strength of 10-40 g / m². 2 The mesh layer density is 20-40 layers / cm.

[0025] 2) The carbon fiber preform is prepared into matrix carbon or matrix carbon and silicon carbide by chemical vapor deposition and / or liquid phase impregnation-pyrolysis, with a deposition density of 1.3–2.5 g / cm³. 3 .

[0026] The process for preparing carbon matrix by chemical vapor deposition is as follows: carbon fiber preforms are placed in a deposition furnace, and carbon-containing gas sources (natural gas, methane, propylene, propane, etc., with nitrogen or hydrogen as diluent gas, and the flow ratio of carbon source gas to diluent gas is 1:0 to 3) are introduced at a temperature of 800 to 1350°C, and deposition is carried out for 50 to 250 hours.

[0027] The impregnation-pyrolysis process for preparing the carbon matrix involves the following steps: The carbon fiber preform undergoes vacuum pressure impregnation with resin (furan, phenolic resin, and furfuryl ketone, etc.) or asphalt (petroleum asphalt, coal tar pitch), followed by curing and pyrolysis (resin: 900–1050℃, atmospheric pressure; asphalt: 750–850℃, 50–200 MPa) for densification. The impregnation pressure is 2.0–6.0 MPa, and the impregnation time is 2–10 h; the curing temperature is 160–230℃, and the curing time is 10–50 h; the pyrolysis time is 2–20 h.

[0028] The process for preparing silicon carbide substrate by chemical vapor deposition is as follows: carbon fiber preform is placed in a deposition furnace and deposited at a temperature of 1000-1300℃ with a gas source (trichloromethylsilane, hydrogen as carrier gas and dilution gas, and the flow ratio of trichloromethylsilane to hydrogen is 1:1-20) for 30-120 hours.

[0029] The liquid-phase impregnation-pyrolysis process for preparing silicon carbide matrix involves the following densification processes: vacuum pressure impregnation with silicon-containing precursors (polycarbosilane PCS, polymethylsilane PMS), curing, and pyrolysis. The impregnation pressure is 1.0–6.0 MPa, and the impregnation time is 2–10 h; the curing temperature is 120–240℃, and the curing time is 10–60 h; the pyrolysis temperature is 750–1150℃, and the time is 2–20 h; the ceramization temperature is 1150–1650℃, and the time is 2–10 h.

[0030] The lead hole of the lung nodule positioning needle of the present invention can fix the connecting wire, such as nylon, non-degradable silk thread, etc.

[0031] The equipment used in this invention to prepare silver-doped diamond-like composite coatings is the HCSH-DLC650 equipment from Guangdong Huicheng Vacuum Technology Co., Ltd., the PVD850-DLC equipment from Dongguan Huanan New Material Research Co., Ltd., or the DLC-800 equipment from Qingdao Youbaiyu Vacuum Equipment Co., Ltd. This equipment is a coating equipment that combines unbalanced medium-frequency magnetron sputtering and DC arc PECVD technology.

[0032] The method for preparing the lung nodule localization needle of the present invention includes the following steps:

[0033] 1) The carbon-based material is processed into positioning needle blanks through mechanical cutting, grinding and other processes.

[0034] 2) A pyrolytic carbon coating PyC is prepared on the surface of the blank. The coating thickness is 10-50 μm. The PyC coating is generated by chemical vapor deposition. The generation conditions are: using a gaseous carbon source (such as natural gas, methane and other common gaseous carbon sources) and depositing at a temperature of 1000-1800℃ for 10-50 h.

[0035] 3) Further prepare a silver-doped DLC composite coating on the blank. The silver-doped DLC composite coating is a silicon transition layer-silver-doped DLC gradient film. The cleaned blank is placed in a coating equipment combining unbalanced medium-frequency magnetron sputtering and DC arc PECVD. The vacuum is evacuated to the working vacuum level. First, remove the impurity gas in the furnace, and then clean the workpiece with an ion source. Then, first deposit the silicon transition film by unbalanced medium-frequency magnetron sputtering, and then deposit the silver-doped DLC film by unbalanced medium-frequency magnetron sputtering-DC arc PECVD. The deposition is carried out alternately. During the alternating preparation of silicon transition film and silver-doped DLC film, with the preparation of each silicon transition film, the silver target power in the preparation of the next silver-doped DLC film is reduced by 0.1 to 0.3 kW compared with the preparation of the previous silver-doped DLC film, until the periodic gradient coating of silicon transition film / silver-doped DLC film is completed. After the coating is completed, wait for the furnace temperature to drop to room temperature and then take out the carbon-based material.

[0036] The process for cleaning the blank is as follows: the blank is ultrasonically cleaned with purified water and ethanol in succession. The cleaning temperature is 20-32℃ and the cleaning time is 10-30min. After cleaning, the blank is dried and ready for use.

[0037] The process for removing impurity gases from the furnace is as follows: Ar gas is introduced into the vacuum chamber at a flow rate of 50–120 sccm, and the vacuum degree is 4.0 × 10⁻⁻¹. 1 ~7.0×10- 1 Pa, the negative bias voltage of the workpiece is 400-800V, and the degassing time is 10-30min.

[0038] The process for cleaning workpieces using an ion source is as follows: Ar gas flow rate is 60–100 sccm, and vacuum degree is 3.0 × 10⁻⁻¹. 1 ~6.0×10- 1 Pa, ion source power of 0.9-1.2kW, workpiece negative bias voltage of 400-800V, cleaning time of 15-40min.

[0039] The silicon transition film preparation process is as follows: Ar gas flow rate 60–100 sccm, silicon target power 0.5–3 kW, silicon, vacuum degree 1.0 × 10⁻⁻¹ 1 ~4.0×10- 1 Pa, ion source power of 0.5-2kW, workpiece negative bias voltage of 50-400V, deposition time of 10-80min.

[0040] The process for preparing silver-doped DLC films is as follows: Ar gas flow rate is 20–100 sccm, gaseous carbon source flow rate is 10–100 sccm, and vacuum degree is 1.0 × 10⁻⁻¹. 1 ~4.0×10- 1 Pa, ion source power of 0.5-3kW, silver-palladium power of 0.1-1kW, Ag target purity of not less than 99.9wt%, workpiece negative bias voltage of 50-600V, deposition time of 30-540min;

[0041] 4) Finally, the lung nodule positioning needle product is obtained.

[0042] Compared with existing technologies, the beneficial technical effects of the present invention are as follows:

[0043] This invention utilizes carbon-based materials as a substrate and combines vapor deposition, unbalanced mid-frequency magnetron sputtering, and DC arc PECVD to deposit a PyC coating and a silver-doped DLC composite coating on its surface to obtain a lung nodule positioning needle. This method is simple to operate, easy to control precisely, and conducive to industrial production. In particular, the method of combining unbalanced mid-frequency magnetron sputtering with DC arc PECVD can deposit a gradient silver-doped DLC coating on the surface of carbon-based materials, and can better control the silver content without changing the DLC coating process parameters, stably controlling the silver content within the range of 1-20% that is most effective in improving the film performance.

[0044] The silver-doped DLC composite coating in the lung nodule positioning needle of this invention is composed of n layers of silicon transition film and n layers of silver-doped DLC film stacked alternately. By incorporating silver into the DLC coating, the silver-doped DLC composite coating bonds more tightly with the atoms in the silicon transition layer, reducing the internal stress of the entire silver-doped DLC coating and greatly improving the bonding force between the entire composite coating and the carbon-based material. Furthermore, by controlling the film preparation process parameters and the number of stacked layers, a composite coating with good wear resistance, hardness, and adhesion can be obtained. The critical load for bonding between the silver-doped DLC composite coating and the carbon-based material of this invention can reach more than 10N.

[0045] The silver-doped DLC composite coating prepared on the surface of the lung nodule positioning needle of the present invention can effectively reduce the surface friction coefficient of carbon-based materials, improve their wear resistance, and improve adverse reactions in the human body caused by friction and powdering of carbon-based materials after implantation. Compared with carbon-based materials without silver-doped DLC composite coating, the powdering phenomenon after friction is significantly improved, and the friction coefficient is significantly reduced.

[0046] The lung nodule localization needle of the present invention uses carbon-based material as the matrix. Carbon material has good biocompatibility and can remain in place for a long time. In addition, the carbon-based coating has anticoagulant properties, which can reduce bleeding caused by metal foreign bodies.

[0047] The lung nodule localization needle of the present invention has a flat tip at the front of the cone, which makes it less likely to damage lung tissue and avoids puncturing the mass, thus reducing the risk of metastasis of exfoliated tumor cells.

[0048] The surface layer of the lung nodule positioning needle of the present invention is an Ag-containing coating, which has significant antibacterial properties and effectively reduces the probability of infection. It can improve the antibacterial properties of the lung nodule positioning needle coating on the carbon-based material surface, increasing the antibacterial properties by 15-40%. Attached Figure Description

[0049] Figure 1 This is an actual image of a carbon-based insertable lung nodule localization needle.

[0050] Figure 2 Image of a carbon-based embedded lung nodule localization needle. Detailed Implementation

[0051] To make the present invention clearer, the present invention will be described in detail below with reference to specific embodiments. The specific embodiments described herein are only used to further explain the present invention in detail, and do not limit the scope of protection of the claims of the present invention.

[0052] Performance testing: In the following examples, the mechanical properties of the coating were tested using nanoindentation and nanoscratching methods; the coefficient of friction of the film was measured using a ball-and-disc friction tester; and the improvement of the coating's biocompatibility with the substrate was verified using endothelial cell proliferation and E. coli survival experiments.

[0053] The specific preparation methods of carbon-based materials in the following specific embodiments and comparative embodiments are as follows:

[0054] 1) Use 25mm wide 12k carbon fiber bundles with 20g / m 2 Carbon fiber mesh is stacked and needle-punched into carbon fiber preforms with a mesh layer density of 22 layers / cm.

[0055] 2) The carbon fiber preform was placed in a deposition furnace, and propylene and nitrogen gas were introduced at 950℃ (propylene to nitrogen flow rate ratio of 1:2) for 150 h to prepare a preform with a density of 1.5 g / cm³. 3 Carbon-based material preform.

[0056] Example 1

[0057] 1) Carbon-based material blanks are processed into positioning pin blanks through mechanical cutting, grinding, and other processes; such as... Figure 1As shown: the needle length is 12mm; the needle bar diameter is 1.8mm; the lead hole is located on the needle bar and its diameter is 0.5mm; the pin bar length is 5mm and its diameter is 1.3mm; the cone tip angle is 40°.

[0058] 2) Using methane and nitrogen as gas sources (methane to nitrogen flow ratio of 1:5), deposition was carried out at 1500℃ for 20h; a PyC coating was prepared on the surface of the blank, and the thickness of the pyrolytic carbon coating was 30μm.

[0059] 3) Further prepare a silver-doped DLC composite coating on top of 2). The silver-doped DLC composite coating is a silicon transition layer-Ag-doped DLC gradient film layer, as detailed below:

[0060] A. Cleaning the blanks: The blanks are ultrasonically cleaned with purified water and ethanol in succession. The cleaning temperature is 28℃ and the cleaning time is 20min. After cleaning, they are dried and ready for use.

[0061] B. Place the cleaned blank substrate in a coating equipment that combines unbalanced medium-frequency magnetron sputtering and DC arc PECVD, and evacuate it to the working vacuum level.

[0062] C. Remove impurities from the furnace: Introduce Ar gas into the vacuum chamber at a flow rate of 100 sccm, maintaining a vacuum level of 5.0 × 10⁻⁻¹. 1 Pa, the workpiece negative bias voltage is 800V, and the degassing time is 20min.

[0063] D. Ion source cleaning of workpiece: Ar gas flow rate is 80 sccm, vacuum degree is 4.0 × 10⁻⁴. 1 Pa, ion source power is 1kW, workpiece negative bias voltage is 800V, cleaning time is 30min.

[0064] E. Preparation of silicon transition film: Ar gas flow rate is 60 sccm, vacuum degree is 2.0 × 10⁻⁻¹ 1 Pa, silicon target power is 1kW, ion source power is 0.9kW, workpiece negative bias voltage is 150V, and coating time is 10min.

[0065] F. Preparation of silver-doped DLC film: Ar gas flow rate was 60 sccm, acetylene gas flow rate was 80 sccm, and vacuum degree was 2.0 × 10⁻⁴. 1 Pa, ion source power of 1.2kW, silver target power of 0.4kW, workpiece negative bias voltage of 400V, coating time of 60min.

[0066] G. Prepare silicon transition films and silver-doped DLC films alternately according to steps E and F. With each silicon transition film prepared, the silver target power in the preparation of the next silver-doped DLC film decreases by 0.1 kW compared to the silver target power in the preparation of the previous silver-doped DLC film, until the periodic gradient coating of silicon transition films / silver-doped DLC films is completed, resulting in a total of 6 silicon transition film / silver-doped DLC film gradient coatings with an overall silver content of 1.2%, a thickness of 0.15 μm for each silicon transition film, and a thickness of at least 0.3 μm for each silver-doped DLC film.

[0067] The silver-doped DLC coating prepared in this embodiment exhibits high adhesion to the carbon-based lung nodule positioning needle, with a value of 12N. This reduces the wear rate on the surface of the carbon-based lung nodule positioning needle, resulting in a friction coefficient of 0.06 and a wear rate of 5.7 × 10⁻⁶. -7 mm 3 / N·m. This effectively improved the antibacterial properties of the carbon-based lung nodule positioning needle. Compared to the uncoated carbon-based lung nodule positioning needle, in this embodiment, the E. coli survival rate of the carbon-based lung nodule positioning needle with the silver-doped DLC coating decreased from 100% to 81% in the E. coli survival experiment, and the endothelial cell proliferation rate increased from 70% to 87% in the endothelial cell proliferation experiment.

[0068] Example 2

[0069] 1) Carbon-based material blanks are processed into positioning pin blanks through mechanical cutting, grinding, and other processes; such as... Figure 2 As shown: the needle length is 10mm; the needle bar diameter is 1.5mm; the pin bar length is 3mm and the diameter is 1.1mm; the lead hole is located on the pin bar and its diameter is 0.4mm; the cone tip angle is 36°.

[0070] 2) Using methane and nitrogen as gas sources (methane to nitrogen flow ratio of 1:5), deposition was carried out at 1500℃ for 20h; a PyC coating was prepared on the surface of the blank, and the thickness of the pyrolytic carbon coating was 30μm.

[0071] 3) Further prepare a silver-doped DLC composite coating on top of 2). The silver-doped DLC composite coating is a silicon transition layer-Ag-doped DLC gradient film layer, as detailed below:

[0072] Step 3) involves the deposition of a silver-doped DLC composite coating as follows:

[0073] A. Cleaning the blanks: The blanks are ultrasonically cleaned with purified water and ethanol in succession. The cleaning temperature is 28℃ and the cleaning time is 20min. After cleaning, they are dried and ready for use.

[0074] B. Place the cleaned blank in a coating equipment that combines unbalanced medium-frequency magnetron sputtering and DC arc PECVD, and evacuate it to the working vacuum level.

[0075] C. Remove impurities from the furnace: Introduce Ar gas into the vacuum chamber at a flow rate of 100 sccm, maintaining a vacuum level of 5.0 × 10⁻⁻¹. 1 Pa, the workpiece negative bias voltage is 800V, and the degassing time is 20min.

[0076] D. Ion source cleaning of workpiece: Ar gas flow rate is 80 sccm, vacuum degree is 4.0 × 10⁻⁴. 1 Pa, ion source power is 1kW, workpiece negative bias voltage is 800V, cleaning time is 30min.

[0077] E. Preparation of silicon transition film: Ar gas flow rate is 60 sccm, vacuum degree is 2.0 × 10⁻⁻¹ 1 Pa, silicon target power is 1kW, ion source power is 0.9kW, workpiece negative bias voltage is 150V, and coating time is 10min.

[0078] F. Preparation of silver-doped DLC film: Ar gas flow rate was 60 sccm, acetylene gas flow rate was 100 sccm, and vacuum degree was 2.0 × 10⁻⁴. 1 Pa, ion source power of 1.2kW, silver target power of 0.8kW, workpiece negative bias voltage of 600V, coating time of 60min.

[0079] G. Prepare silicon transition films and silver-doped DLC films alternately according to the processes in steps E and F. With each silicon transition film prepared, the silver target power in the preparation of the next silver-doped DLC film decreases by 0.15 kW compared to the silver target power in the preparation of the previous silver-doped DLC film, until the periodic gradient coating of silicon transition films / silver-doped DLC films is completed, resulting in a total of 4 silicon transition film / silver-doped DLC film gradient coatings with an overall silver content of 3.8%, a thickness of 0.15 μm for each silicon transition film, and a thickness of at least 0.45 μm for each silver-doped DLC film.

[0080] The silver-doped DLC coating prepared in this embodiment exhibits high adhesion to the carbon-based lung nodule positioning needle, with a value of 15N. This reduces the wear rate on the surface of the carbon-based lung nodule positioning needle, with a friction coefficient of 0.03 and a wear rate of 3.4 × 10⁻⁶. -7 mm 3 / N·m. This effectively improved the antibacterial properties of the carbon-based lung nodule positioning needle. Compared to the uncoated carbon-based lung nodule positioning needle, in this embodiment, the E. coli survival rate of the carbon-based lung nodule positioning needle with the silver-doped DLC coating decreased from 100% to 82% in the E. coli survival experiment, and the endothelial cell proliferation rate increased from 70% to 90% in the endothelial cell proliferation experiment.

[0081] Example 3

[0082] The operation steps are exactly the same as in Example 2. The only difference is that the total number of silicon transition film / silver-doped DLC film gradient coating layers is 12, the overall silver content of the film is 2.1%, the thickness of each silicon transition film layer is 0.15 μm, and the thickness of each silver-doped DLC film layer is at least 0.39 μm.

[0083] The silver-doped DLC coating prepared in this embodiment exhibits high adhesion to the carbon-based lung nodule positioning needle, with a value of 11N. This reduces the wear rate on the surface of the carbon-based lung nodule positioning needle, resulting in a friction coefficient of 0.04 and a wear rate of 3.9 × 10⁻⁶. -7 mm 3 / N·m. This effectively improved the antibacterial properties of the carbon-based lung nodule positioning needle. Compared to the uncoated carbon-based lung nodule positioning needle, in this embodiment, the E. coli survival rate of the carbon-based lung nodule positioning needle with the silver-doped DLC coating decreased from 100% to 80% in the E. coli survival experiment, and the endothelial cell proliferation rate increased from 70% to 88% in the endothelial cell proliferation experiment.

[0084] Example 4

[0085] The operation steps are exactly the same as in Example 2. The only difference is that the silver target power is the same during the preparation of each silver-doped DLC film layer. The silver target power is 0.8kW, the overall silver content of the film layer is 4.9%, the thickness of each silicon transition layer is 0.15μm, and the thickness of each silver-doped DLC film layer is 0.51μm.

[0086] The silver-doped DLC coating prepared in this embodiment exhibits high adhesion to the carbon-based lung nodule positioning needle, with a value of 11N. This reduces the wear rate on the surface of the carbon-based lung nodule positioning needle, with a friction coefficient of 0.05 and a wear rate of 4.2 × 10⁻⁶. -7 mm 3 / N·m. This effectively improved the antibacterial properties of the carbon-based lung nodule positioning needle. Compared to the uncoated carbon-based lung nodule positioning needle, in this embodiment, the E. coli survival rate of the carbon-based lung nodule positioning needle with the silver-doped DLC coating decreased by 79% from 100% in the E. coli survival experiment, and the endothelial cell proliferation rate increased from 70% to 85% in the endothelial cell proliferation experiment.

[0087] Comparative Example 1

[0088] The only difference between this comparative example and Example 1 is that: no silicon transition film layer was prepared, and a silver-doped DLC coating of the same total thickness was directly prepared on the surface of the carbon-based lung nodule positioning needle.

[0089] The silver-doped DLC coating without silicon transition layer prepared in this comparative example peels off directly from the carbon-based lung nodule positioning needle, resulting in poor adhesion.

[0090] Comparative Example 2

[0091] The only difference between this comparative example and Example 1 is that no silver element is incorporated into the DLC film.

[0092] The silicon transition film / undoped silver DLC thin film composite coating prepared in this comparative example has low adhesion to the carbon-based lung nodule positioning needle. Its value is 4 N, the coefficient of friction is 0.10, and the wear rate is 9.8 × 10⁻⁶. -7 mm 3 / N·m. In this example, the survival rate of *E. coli* in the prepared coated carbon-based lung nodule positioning needle decreased from 100% to 98% in the *E. coli* survival experiment, while the endothelial cell proliferation rate increased from 70% to 74% in the endothelial cell proliferation experiment.

[0093] Table 1 Comparison of Performance Test Results

[0094]

Claims

1. A carbon-based material lung nodule positioning needle, characterized in that: The device includes an insertable needle or an embedded needle; the insertable needle includes a needle bar with a tapered tip at the front end and a pin at the rear end, and the needle bar or pin is provided with a lead hole; the embedded needle includes a needle bar with a tapered or blunt tip at the front end and a pin at the rear end, and the pin is provided with a lead hole; the lung nodule positioning needle is composed of a carbon-based material and a PyC coating and a silver-doped DLC composite coating on its surface; the silver-doped DLC composite coating is composed of n layers of silicon transition film and n layers of silver-doped DLC film alternately stacked; wherein, n=2~10; the silver doping amount of each silver-doped DLC film layer in the silver-doped DLC composite coating decreases gradually from the inner layer to the outer layer; the silver mass percentage content in the silver-doped DLC composite coating is 1%~20%, and the silver mass percentage content in the outermost silver-doped DLC film layer is not higher than 10%; The thickness of the PyC coating is 10~50μm; The thickness of the silicon transition film is 0.1~1.5 μm; The thickness of the silver-doped DLC film is 0.3~3.5 μm.

2. The carbon-based lung nodule positioning needle according to claim 1, characterized in that: The diameter of the needle bar is 1.5~2mm; the diameter of the pin bar is 1.0~1.5mm; the diameter of the lead hole is 0.2~0.5mm; and the taper of the cone tip is >30°.

3. A method for preparing a carbon-based material lung nodule positioning needle according to claim 1 or 2, characterized in that: After forming a needle blank from carbon-based material through machining, a PyC coating is first deposited on the surface of the blank, and then a silver-doped DLC composite coating is deposited to obtain the needle.

4. The method for preparing a carbon-based material lung nodule positioning needle according to claim 3, characterized in that: The PyC coating is generated by chemical vapor deposition, wherein the chemical vapor deposition conditions are: under the condition of introducing a gaseous carbon source, at a temperature of 1000~1800℃, deposition is carried out for 10~50 hours.

5. The method for preparing a carbon-based material lung nodule positioning needle according to claim 3, characterized in that: The silver-doped DLC composite coating is deposited by a combination of unbalanced intermediate frequency magnetron sputtering and DC arc PECVD. First, a silicon transition film is deposited by unbalanced intermediate frequency magnetron sputtering, and then a silver-doped DLC film is deposited by a combination of unbalanced intermediate frequency magnetron sputtering and DC arc PECVD. The deposition is performed alternately.

6. The method for preparing a carbon-based material lung nodule positioning needle according to claim 5, characterized in that: The conditions for depositing the silicon transition film are as follows: Ar gas flow rate is 60~100 sccm, silicon target power is 0.5~3 kW, vacuum degree is 1.0×10-1~4.0×10-1 Pa, ion source power is 0.5~2 kW, workpiece negative bias voltage is 50~400 V, and coating time is 10~80 min. The deposition conditions for the silver-doped DLC film are as follows: Ar gas flow rate of 20~100 sccm, gas carbon source flow rate of 10~100 sccm, vacuum degree of 1.0×10-1~4.0×10-1 Pa, ion source power of 0.5~3 kW, silver target power of 0.1~1 kW, silver target purity of not less than 99.9 wt%, workpiece negative bias voltage of 50~600 V, and deposition time of 30~540 min; and during the deposition process of any two adjacent silver-doped DLC films, the silver target power when depositing the outer silver-doped DLC film is 0.1~0.3 kW lower than that when depositing the inner silver-doped DLC film.

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