An implant-grade platinum-iridium needle, its preparation method and application

Abstract

The application belongs to the technical field of medical material processing, and particularly relates to an implant-grade platinum-iridium needle as well as a preparation method and application thereof. The method comprises the steps of vacuum smelting, casting, cold rolling, primary heat treatment, drawing, cryogenic treatment, straightening, cutting, secondary heat treatment, and coating preparation. The platinum-iridium needle product with high strength, high toughness, a bright surface, and a flat end is prepared through cryogenic treatment, bright straightening, and special cutting. The tensile strength of the platinum-iridium needle is greater than 1000 Mpa, and the bending fracture frequency is greater than 50 times. The performance of the product is superior to that of imported products, and the product can be applied to a dynamic blood glucose meter.

Description

Technical Field

[0001] This invention belongs to the field of medical material processing technology, specifically relating to an implantable platinum-iridium needle, its preparation method, and its application. Background Technology

[0002] Biomedical materials are the foundation and support for the development of medical devices, especially as China's population ages and the number of people with chronic diseases such as hyperglycemia increases significantly. The development of key medical devices is a crucial prerequisite for safeguarding national health. Platinum-iridium needles are primarily used in the signal transmission of continuous glucose monitoring (CGM) devices. They are the core material for detecting blood glucose fluctuations and transmitting blood glucose information, and are fundamental to the manufacture of CGM devices. Because this material needs to be implanted in the human body after 14 days, the platinum-iridium needles require three key qualities: first, good strength to prevent breakage within the body; second, good flexibility to reduce the foreign body sensation after implantation; and third, a smooth surface and good straightness to ensure smooth insertion through the skin.

[0003] Currently, the manufacturing technology for platinum-iridium electrode needles is completely monopolized by foreign countries, and China mainly relies on imports for platinum-iridium needles. No domestic manufacturers are capable of mass production. Imported platinum-iridium needles suffer from problems such as excessive surface damage, unstable straightness, uneven cuts, and low strength and toughness (e.g., ...). Figure 1-3 As shown in the figure, the strength of most imported platinum-iridium needles is between 400-700 MPa, and they are prone to breakage after being bent 10-15 times. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an implantable platinum-iridium needle, its preparation method, and its application. This invention produces a platinum-iridium needle product with high strength, high toughness, a bright surface, and flush ends through cryogenic treatment, bright straightening, and special cutting. The tensile strength is >1000 MPa, and the number of bending fractures is >50 times, demonstrating superior performance compared to imported products. Specifically, this invention includes the following:

[0005] A method for preparing an implantable platinum-iridium needle includes the following steps:

[0006] (1) Vacuum melting: Platinum and iridium raw materials are placed in a melting equipment at a mass ratio of platinum:iridium = (89.5-90.5):(9.5-10.5) and vacuum melting is carried out to obtain a mixed melt;

[0007] (2) Casting: The mixed melt is cast into a water-cooled mold with an inner diameter of 20-30mm to obtain a platinum-iridium rod with a diameter of φ20-30mm;

[0008] (3) Cold rolling: The platinum-iridium rod is heated and then cold rolled to obtain a cold-rolled platinum-iridium rod with a diameter of φ3-5mm;

[0009] (4) First heat treatment: The cold-rolled platinum-iridium rod is subjected to a first heat treatment in a vacuum atmosphere. The first heat treatment temperature is 1000-1300℃ and the time is 30-90min to obtain the heat-treated platinum-iridium rod.

[0010] (5) Drawing and cryogenic treatment: The heat-treated platinum-iridium rod is drawn to φ0.15-0.3mm in liquid nitrogen, and then immersed in liquid nitrogen for 1-5 minutes for cryogenic treatment to obtain platinum-iridium wire;

[0011] (6) Straightening: The platinum-iridium wire is straightened by sinusoidal pressure. The straightening module is made of high mirror wear-resistant white rubber, which can ensure that a shallow straightening spiral pattern is obtained while ensuring straightness, and the straightened platinum-iridium wire material is obtained.

[0012] (7) Cutting: The straightened platinum-iridium wire is fixed in the copper tube, and the copper tube and the platinum-iridium wire in the copper tube are cut simultaneously using a slow wire cutting method. This can avoid deformation of the platinum-iridium needle during the cutting process and obtain a platinum-iridium needle. The platinum-iridium needle cut in this way has a flat break and no obvious burrs or cut marks.

[0013] (8) Secondary heat treatment: The platinum-iridium needle is placed in the limiting groove and heat-treated in a vacuum environment of 300-500℃ for 10-30 minutes. After cooling, the heat-treated platinum-iridium needle is obtained.

[0014] (9) Preparation of coating: The heat-treated platinum-iridium needle is immersed in the coating, then taken out and dried to obtain a platinum-iridium needle with a coating on the outside, namely the implantable platinum-iridium needle. The implantable platinum-iridium needle has good straightness, high strength, high toughness and PTFE coating.

[0015] Preferably, the vacuum degree of the vacuum melting in step (1) is 5×10⁻⁶. -3 -5×10 -2 Pa, wherein the melting temperature is 2500-2600℃.

[0016] Preferably, the water-cooled mold in step (2) is a water-cooled copper mold.

[0017] Preferably, the liquid nitrogen in step (5) is industrial liquid nitrogen with a temperature not higher than -196℃; and / or, the platinum-iridium wire in step (5) has a tensile strength of 1300-1500 MPa and a hardness of 250-300 HV.

[0018] Preferably, the roughness of the straightening module in step (6) is <0.2μm, the straightening pressure is 0.5-1N, and the speed is 1-3m / min; and / or, the straightness of the platinum-iridium wire after straightening in step (6) is 0.05-0.1mm, and the surface is bright without obvious scratches.

[0019] Preferably, the diameter of the copper tube in step (7) is 0.16-0.31 mm; and / or, the length of the platinum-iridium needle in step (7) is 15-30 mm and the straightness is 0.05-0.1 mm.

[0020] Preferably, the diameter of the limiting groove in step (8) is 0.16-0.31 mm; and / or, the platinum-iridium needle after heat treatment in step (8) has a tensile strength >1000 MPa, and can withstand 50 repeated 90° bends without breaking, and has good electrical conductivity.

[0021] Preferably, the coating in step (9) is a PTFE water-based coating, and the thickness of the coating is 15-50 μm; and / or, the drying temperature in step (9) is 150-300℃ and the drying time is 30-120 min.

[0022] An implantable platinum-iridium needle prepared using the method described in this invention.

[0023] An application of the implantable platinum-iridium needle described in this invention in a continuous glucose meter.

[0024] The beneficial effects of this invention are:

[0025] (1) The present invention improves the hardness of platinum-iridium wire by cryogenic treatment, avoids the straightening module from scratching the wire surface during the straightening process, and obtains platinum-iridium straight wire with good straightness and smooth surface without scratches by straightening with wear-resistant and high-gloss rubber straightening module.

[0026] (2) Cutting is performed by limiting the copper tube, so as to avoid the damage to the straightness of the platinum-iridium needle by external force during the cutting process, and a hard platinum-iridium needle with a flat fracture and good straightness is obtained.

[0027] (3) The material toughness is improved by a secondary heat treatment method, and the straightness of the platinum-iridium needle is further guaranteed by the innovative use of limiting heat treatment;

[0028] (4) The platinum-iridium needle product prepared by the present invention has high strength, high toughness, bright surface and flush end, tensile strength > 1000 MPa, bending fracture number > 50 times, and the product performance is better than imported products. Attached Figure Description

[0029] Figure 1 Image of the cut surface of an imported platinum-iridium needle;

[0030] Figure 2 Image of the cut edge of an imported platinum-iridium needle;

[0031] Figure 3 This is a surface condition diagram of an imported platinum-iridium needle;

[0032] Figure 4 This is a view of the cut surface of the platinum-iridium needle prepared according to the present invention;

[0033] Figure 5 This is a cut edge diagram of the platinum-iridium needle prepared according to the present invention;

[0034] Figure 6 This is a surface state diagram of the platinum-iridium needle prepared according to the present invention. Detailed Implementation

[0035] The following is in conjunction with the appendix Figure 1-6 The present invention will be described in detail below with reference to specific embodiments. The embodiments shown below are not intended to limit the scope of the invention as described in the claims. Furthermore, the complete contents of the configurations shown in the embodiments below are not limited to those necessary for the solution of the invention as described in the claims.

[0036] A method for preparing an implantable platinum-iridium needle includes the following steps:

[0037] (1) Vacuum melting: Platinum and iridium raw materials are placed in a melting equipment for vacuum melting at a mass ratio of platinum:iridium = (89.5-90.5):(9.5-10.5). The vacuum degree of the vacuum melting is 5×10 -3 -5×10 -2 Pa, melting temperature of 2500-2600℃, to obtain a mixed melt;

[0038] (2) Casting: The mixed melt is cast into a water-cooled copper mold with an inner diameter of 20-30mm to obtain a platinum-iridium rod with a diameter of φ20-30mm;

[0039] (3) Cold rolling: The platinum-iridium rod is heated and then cold rolled to obtain a cold-rolled platinum-iridium rod with a diameter of φ3-5mm;

[0040] (4) First heat treatment: The cold-rolled platinum-iridium rod is subjected to a first heat treatment in a vacuum atmosphere. The first heat treatment temperature is 1000-1300℃ and the time is 30-90min to obtain the heat-treated platinum-iridium rod.

[0041] (5) Drawing and cryogenic treatment: The heat-treated platinum-iridium rod is drawn to φ0.15-0.3mm in industrial liquid nitrogen at a temperature not higher than -196℃, and then immersed in liquid nitrogen for 1-5 minutes for cryogenic treatment to obtain platinum-iridium wire with a tensile strength of 1300-1500Mpa and a hardness of 250-300HV;

[0042] (6) Straightening: The platinum-iridium wire is straightened by sinusoidal pressure. The straightening module is made of white rubber with a roughness of <0.2μm and high mirror wear resistance. The straightening pressure is controlled at 0.5-1N and the speed is 1-3m / min. This ensures that a shallow straightening spiral pattern is obtained while maintaining straightness. The straightened platinum-iridium wire with a straightness of 0.05-0.1mm and a bright surface without obvious scratches is obtained.

[0043] (7) Cutting: The straightened platinum-iridium wire is fixed in a copper tube with a diameter of 0.16-0.31mm. The copper tube and the platinum-iridium wire in the copper tube are cut simultaneously using a slow wire cutting method. This can avoid deformation of the platinum-iridium needle during the cutting process and obtain a platinum-iridium needle with a length of 15-30mm and a straightness of 0.05-0.1mm. The platinum-iridium needle cut in this way has a flat break and no obvious burrs or cut marks.

[0044] (8) Secondary heat treatment: The platinum-iridium needle is placed in a limiting groove with a diameter of 0.16-0.31 mm and heat-treated in a vacuum environment of 300-500℃ for 10-30 min. After cooling, the platinum-iridium needle after heat treatment is obtained. The platinum-iridium needle after heat treatment has a tensile strength of >1000 MPa, and can withstand 50 repeated bending at 90° without breaking. It also has good electrical conductivity.

[0045] (9) Coating preparation: The heat-treated platinum-iridium needle is immersed in PTFE water-based coating, then removed and dried at 150-300℃ for 30-120 min to obtain a platinum-iridium needle with a coating of 15-50 μm thickness, i.e., the implantable platinum-iridium needle (e.g. Figure 4-6 As shown, the implantable platinum-iridium needle has good straightness, high strength, high toughness, and is coated with PTFE.

[0046] The present invention will be further described below with reference to the embodiments.

[0047] Example 1

[0048] Prepare PTFE-coated insulating platinum-iridium wire (i.e., implantable platinum-iridium) needles according to the following steps:

[0049] Raw materials were prepared according to a ratio of 90% platinum and 10% iridium by mass and placed in a medium-frequency induction melting furnace. The melting temperature was 2500℃ and the vacuum degree was 5×10⁻⁶. -3The material is cast into a water-cooled copper mold to obtain a φ20mm bar. After heat treatment, the φ20mm bar is cold-rolled to 3mm and then heat-treated again at 1000℃ for 90 minutes in a vacuum atmosphere. It is then drawn to φ0.15mm in industrial liquid nitrogen at -196℃ and immersed in liquid nitrogen for 5 minutes for cryogenic treatment, yielding a platinum-iridium alloy wire with a tensile strength of 1500MPa and a hardness of 300HV. The φ0.15mm platinum-iridium wire is straightened using sinusoidal pressure. The straightening module uses high-mirror-finish, wear-resistant white rubber to ensure a shallow straightening spiral pattern while maintaining straightness. The straightening module roughness is 0.15μm, the straightening pressure is 0.5N, and the straightening speed is 2m / min. After straightening, the wire straightness is <0.05mm, and the surface is bright with no obvious scratches. The straightened platinum-iridium wire is cut using a slow wire cutting machine. To avoid deformation of the platinum-iridium needle during the cutting process, the platinum-iridium needle needs to be fixed in a φ0.16mm copper tube. The tooling and the platinum-iridium wire are cut simultaneously to obtain a platinum-iridium needle with a length of 15mm. The cut of the platinum-iridium needle obtained by this method is flat, with no obvious burrs or cut marks, and the straightness of the platinum-iridium needle is 0.05mm. The straightened wire is then heat-treated. To prevent the annealed wire from bending, the platinum-iridium needle is placed in a φ0.16mm limiting groove for heat treatment. The heat treatment temperature is 300℃, the heat treatment time is 30min, and the heat treatment atmosphere is vacuum heat treatment with furnace cooling. The heat-treated platinum-iridium needle exhibits significantly increased toughness, achieving a tensile strength of 1400 MPa, withstanding 54 repeated 90° bends without breakage, and demonstrating excellent electrical conductivity. The heat-treated platinum-iridium needle is then immersed in a water-based PTFE coating and dried at 150°C for 120 minutes, resulting in a coating thickness of 15 μm. This yields a platinum-iridium electrode needle with a PTFE coating that exhibits good straightness, high strength, and high toughness.

[0050] Example 2

[0051] Prepare PTFE-coated insulating platinum-iridium wire (i.e., implantable platinum-iridium) according to the following steps:

[0052] A method for preparing an implantable platinum-iridium electrode needle for signal transmission in a continuous glucose monitoring system, characterized by a special platinum-iridium needle preparation process. Raw materials are prepared in a ratio of 90% platinum and 10% iridium by mass and placed in a medium-frequency induction melting furnace at a melting temperature of 2550℃ and a vacuum degree of 5×10⁻⁶. -2Pa was cast into a water-cooled copper mold to obtain a φ25mm bar. After heat treatment, the φ25mm bar was cold-rolled to 4mm and then heat-treated again at 1200℃ for 60 minutes in a vacuum atmosphere. It was then drawn to φ0.2mm in industrial liquid nitrogen at -196℃ and immersed in liquid nitrogen for 3 minutes for cryogenic treatment, yielding a platinum-iridium alloy wire with a tensile strength of 1400MPa and a hardness of 270HV. The φ0.2mm platinum-iridium wire was straightened using sinusoidal pressure. The straightening module was made of high-mirror-finish, wear-resistant white rubber to ensure a shallow straightening spiral pattern while maintaining straightness. The straightening module roughness was 0.12μm, the straightening pressure was 0.7N, and the straightening speed was 2m / min. After straightening, the straightness of the wire is less than 0.08mm, and the surface is bright without obvious scratches. The straightened platinum-iridium wire is cut using a slow wire cutting machine. To avoid deformation of the platinum-iridium needle during the cutting process, the platinum-iridium needle needs to be fixed in a φ0.21mm copper tube. The tooling and the platinum-iridium wire are cut simultaneously to obtain a platinum-iridium needle with a length of 25mm. The cut of the platinum-iridium needle obtained by this method is flat, without obvious burrs or cut marks, and the straightness of the platinum-iridium needle is 0.08mm. The straightened wire is then heat-treated. To prevent the annealed wire from bending, the platinum-iridium needle is placed in a φ0.21mm limiting groove for heat treatment. The heat treatment temperature is 400℃, the heat treatment time is 20min, and the heat treatment atmosphere is vacuum heat treatment with furnace cooling. The heat-treated platinum-iridium needle exhibits significantly increased toughness, achieving a tensile strength of 1200 MPa, resistance to breakage after 50 repeated 90° bends, and good electrical conductivity. The heat-treated platinum-iridium needle is then immersed in a water-based PTFE coating and dried at 200°C for 90 minutes, resulting in a coating thickness of 25 μm. This yields a platinum-iridium electrode needle with good straightness, high strength, and high toughness, coated with a PTFE coating.

[0053] Example 3

[0054] Prepare PTFE-coated insulating platinum-iridium wire (i.e., implantable platinum-iridium) according to the following steps:

[0055] A method for preparing an implantable platinum-iridium electrode needle for signal transmission in a continuous glucose monitoring system, characterized by a special platinum-iridium needle preparation process. Raw materials are prepared in a ratio of 90% platinum and 10% iridium by mass and placed in a medium-frequency induction melting furnace at a melting temperature of 2600℃ and a vacuum degree of 5×10⁻⁶. -2Pa was cast into a water-cooled copper mold to obtain a φ30mm bar. After heat treatment, the φ30mm bar was cold-rolled to 5mm and then heat-treated again at 1300℃ for 30 minutes in a vacuum atmosphere. It was then drawn to φ0.3mm in industrial liquid nitrogen at -196℃ and immersed in liquid nitrogen for 1 minute for cryogenic treatment, yielding a platinum-iridium alloy wire with a tensile strength of 1300MPa and a hardness of 250HV. The φ0.3mm platinum-iridium wire was straightened using sinusoidal pressure. The straightening module was made of high-mirror-finish, wear-resistant white rubber to ensure a shallow straightening spiral pattern while maintaining straightness. The straightening module roughness was 0.18μm, the straightening pressure was 1N, and the straightening speed was 2m / min. After straightening, the straightness of the wire is less than 0.1 mm, and the surface is bright without obvious scratches. The straightened platinum-iridium wire is cut using a slow wire cutting machine. To avoid deformation of the platinum-iridium needle during the cutting process, the platinum-iridium needle needs to be fixed in a φ0.31 mm copper tube. The tooling and the platinum-iridium wire are cut simultaneously to obtain a platinum-iridium needle with a length of 30 mm. The cut of the platinum-iridium needle obtained by this method is flat, without obvious burrs or cut marks, and the straightness of the platinum-iridium needle is less than 0.1 mm. The straightened wire is then heat-treated. To prevent the annealed wire from bending, the platinum-iridium needle is placed in a φ0.31 mm limiting groove for heat treatment. The heat treatment temperature is 500℃, the heat treatment time is 10 min, and the heat treatment atmosphere is vacuum heat treatment with furnace cooling. The heat-treated platinum-iridium needle exhibits significantly increased toughness, achieving a tensile strength of 1100 MPa, resistance to breakage after 50 repeated 90° bends, and good electrical conductivity. The heat-treated platinum-iridium needle is then immersed in a water-based PTFE coating and dried at 300°C for 30 minutes, resulting in a PTFE-coated platinum-iridium electrode needle with good straightness, high strength, and high toughness.

[0056] Example 4

[0057] A method for preparing an implantable platinum-iridium needle includes the following steps:

[0058] (1) Vacuum melting: Platinum and iridium raw materials are placed in a melting equipment at a mass ratio of platinum:iridium = 89.5:10.5 for vacuum melting. The vacuum degree of the vacuum melting is 5×10 -3 Pa and a melting temperature of 2520℃ were used to obtain a mixed melt;

[0059] (2) Casting: The mixed melt is cast into a water-cooled copper mold with an inner diameter of 22 mm to obtain a platinum-iridium rod with a diameter of φ22 mm;

[0060] (3) Cold rolling: The platinum-iridium rod is heated and then cold rolled to obtain a cold-rolled platinum-iridium rod with a diameter of φ3.5mm;

[0061] (4) First heat treatment: The cold-rolled platinum-iridium rod is subjected to a first heat treatment in a vacuum atmosphere. The first heat treatment temperature is 1100℃ and the time is 40min to obtain the heat-treated platinum-iridium rod.

[0062] (5) Drawing and cryogenic treatment: The heat-treated platinum-iridium rod is drawn to φ0.18mm in industrial liquid nitrogen at a temperature not higher than -200℃, and then immersed in liquid nitrogen for 2 minutes for cryogenic treatment to obtain platinum-iridium wire with a tensile strength of 1350Mpa and a hardness of 260HV.

[0063] (6) Straightening: The platinum-iridium wire is straightened by sinusoidal pressure. The straightening module is made of white rubber with a roughness of <0.1μm and high mirror wear resistance. The straightening pressure is controlled at 0.6N and the speed is 1m / min. This ensures that a shallow straightening spiral pattern is obtained while maintaining straightness. The straightened platinum-iridium wire with a straightness of 0.06mm and a bright surface without obvious scratches is obtained.

[0064] (7) Cutting: The straightened platinum-iridium wire is fixed in a copper tube with a diameter of 0.19 mm. The copper tube and the platinum-iridium wire in the copper tube are cut simultaneously using a slow wire cutting method. This can avoid deformation of the platinum-iridium needle during the cutting process and obtain a platinum-iridium needle with a length of 16 mm and a straightness of 0.06 mm. The platinum-iridium needle cut in this way has a flat break and no obvious burrs or cut marks.

[0065] (8) Secondary heat treatment: The platinum-iridium needle is placed in a limiting groove with a diameter of 0.19 mm and heat-treated in a vacuum environment at 350°C for 15 min. After cooling, the platinum-iridium needle after heat treatment is obtained. The platinum-iridium needle after heat treatment has a tensile strength of >1080 MPa and can withstand 50 repeated bending at 90° without breaking. It also has good electrical conductivity.

[0066] (9) Coating preparation: The heat-treated platinum-iridium needle is immersed in PTFE water-based coating, then removed and dried at 160°C for 40 min to obtain a platinum-iridium needle with a 20 μm thick coating, i.e., the implantable platinum-iridium needle (e.g. Figure 4-6 As shown, the implantable platinum-iridium needle has good straightness, high strength, high toughness, and is coated with PTFE.

[0067] Example 5

[0068] A method for preparing an implantable platinum-iridium needle includes the following steps:

[0069] (1) Vacuum melting: Platinum and iridium raw materials are placed in a melting equipment at a mass ratio of platinum:iridium = 90.5:9.5 for vacuum melting. The vacuum degree of the vacuum melting is 2×10 -2Pa and a melting temperature of 2580℃ were used to obtain a mixed melt;

[0070] (2) Casting: The mixed melt is cast into a water-cooled copper mold with an inner diameter of 25 mm to obtain a φ25 mm platinum-iridium rod;

[0071] (3) Cold rolling: The platinum-iridium rod is heated and then cold rolled to obtain a cold-rolled platinum-iridium rod with a diameter of φ4mm;

[0072] (4) First heat treatment: The cold-rolled platinum-iridium rod is subjected to a first heat treatment in a vacuum atmosphere. The first heat treatment temperature is 1150℃ and the time is 50min to obtain the heat-treated platinum-iridium rod.

[0073] (5) Drawing and cryogenic treatment: The heat-treated platinum-iridium rod is drawn to φ0.2mm in industrial liquid nitrogen at a temperature not higher than -205℃, and then immersed in liquid nitrogen for 3 minutes for cryogenic treatment to obtain a platinum-iridium wire with a tensile strength of 1400Mpa and a hardness of 280HV.

[0074] (6) Straightening: The platinum-iridium wire is straightened by sinusoidal pressure. The straightening module is made of white rubber with a roughness of <0.15μm and high mirror wear resistance. The straightening pressure is controlled at 0.8N and the speed is 2m / min. This ensures that a shallow straightening spiral pattern is obtained while maintaining straightness. The straightened platinum-iridium wire with a straightness of 0.08mm and a bright surface without obvious scratches is obtained.

[0075] (7) Cutting: The straightened platinum-iridium wire is fixed in a copper tube with a diameter of 0.21 mm. The copper tube and the platinum-iridium wire in the copper tube are cut simultaneously using a slow wire cutting method. This can avoid deformation of the platinum-iridium needle during the cutting process and obtain a platinum-iridium needle with a length of 25 mm and a straightness of 0.09-0.1 mm. The platinum-iridium needle cut in this way has a flat break and no obvious burrs or cut marks.

[0076] (8) Secondary heat treatment: The platinum-iridium needle is placed in a limiting groove with a diameter of 0.21 mm and heat-treated in a vacuum environment at 400°C for 20 min. After cooling, the platinum-iridium needle after heat treatment is obtained. The platinum-iridium needle after heat treatment has a tensile strength of >1100 MPa and can withstand 50 repeated 90° bends without breaking. It also has good electrical conductivity.

[0077] (9) Coating preparation: The heat-treated platinum-iridium needle is immersed in PTFE water-based coating, then removed and dried at 220°C for 60 min to obtain a platinum-iridium needle with a 30 μm thick coating, i.e., the implantable platinum-iridium needle (e.g. Figure 4-6 As shown, the implantable platinum-iridium needle has good straightness, high strength, high toughness, and is coated with PTFE.

[0078] Example 6

[0079] A method for preparing an implantable platinum-iridium needle includes the following steps:

[0080] (1) Vacuum melting: Platinum and iridium raw materials are placed in a melting equipment at a mass ratio of platinum:iridium = 90:10 for vacuum melting. The vacuum degree of the vacuum melting is 4×10 -2 Pa, melting temperature 2600℃, to obtain a mixed melt;

[0081] (2) Casting: The mixed melt is cast into a water-cooled copper mold with an inner diameter of 30 mm to obtain a φ30 mm platinum-iridium rod;

[0082] (3) Cold rolling: The platinum-iridium rod is heated and then cold rolled to obtain a cold-rolled platinum-iridium rod with a diameter of φ5mm;

[0083] (4) First heat treatment: The cold-rolled platinum-iridium rod is subjected to a first heat treatment in a vacuum atmosphere. The first heat treatment temperature is 1300℃ and the time is 90min to obtain the heat-treated platinum-iridium rod.

[0084] (5) Drawing and cryogenic treatment: The heat-treated platinum-iridium rod is drawn to φ0.3mm in industrial liquid nitrogen at a temperature not higher than -196℃, and then immersed in liquid nitrogen for 5min for cryogenic treatment to obtain a platinum-iridium wire with a tensile strength of 1500Mpa and a hardness of 300HV.

[0085] (6) Straightening: The platinum-iridium wire is straightened by sinusoidal pressure. The straightening module is made of white rubber with a roughness of <0.2μm and high mirror wear resistance. The straightening pressure is controlled at 1N and the speed is 3m / min. This ensures that a shallow straightening spiral pattern is obtained while maintaining straightness. The straightened platinum-iridium wire with a straightness of 0.1mm and a bright surface without obvious scratches is obtained.

[0086] (7) Cutting: The straightened platinum-iridium wire is fixed in a copper tube with a diameter of 0.31 mm. The copper tube and the platinum-iridium wire in the copper tube are cut simultaneously using a slow wire cutting method. This can avoid deformation of the platinum-iridium needle during the cutting process and obtain a platinum-iridium needle with a length of 30 mm and a straightness of 0.1 mm. The platinum-iridium needle cut in this way has a flat break and no obvious burrs or cut marks.

[0087] (8) Secondary heat treatment: The platinum-iridium needle is placed in a limiting groove with a diameter of 0.31 mm and heat-treated in a vacuum environment of 300-500℃ for 30 min. After cooling, the platinum-iridium needle after heat treatment is obtained. The platinum-iridium needle after heat treatment has a tensile strength of >1050 MPa and can withstand 50 repeated 90° bends without breaking. It also has good electrical conductivity.

[0088] (9) Coating preparation: The heat-treated platinum-iridium needle is immersed in a PTFE water-based coating, then removed and dried at 300°C for 120 min to obtain a platinum-iridium needle with a 50 μm thick coating, i.e., the implantable platinum-iridium needle (e.g., Figure 4-6 As shown, the implantable platinum-iridium needle has good straightness, high strength, high toughness, and is coated with PTFE.

[0089] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an implantable platinum-iridium needle, characterized in that, The process includes the following steps: (1) Vacuum melting: Platinum and iridium raw materials are placed in a melting equipment for vacuum melting according to the mass ratio of platinum:iridium = (89.5-90.5):(9.5-10.5) to obtain a mixed melt; (2) Casting: The mixed melt is cast into a water-cooled mold with an inner diameter of 20-30mm to obtain a platinum-iridium rod with a diameter of φ20-30mm; (3) Cold rolling: The platinum-iridium rod is heated and then cold rolled to obtain a cold-rolled platinum-iridium rod with a diameter of φ3-5mm; (4) First heat treatment: The cold-rolled platinum-iridium rod is subjected to a first heat treatment in a vacuum atmosphere at a temperature of 1000-1300℃ for a time of 30-90min to obtain a heat-treated platinum-iridium rod; (5) Drawing and deep cryogenic treatment: The heat-treated platinum-iridium rod is drawn to φ0.15-0.3mm in liquid nitrogen and then immersed in liquid nitrogen for 1-5min. (6) Straightening: The platinum-iridium wire is straightened by sinusoidal pressure. The straightening module is made of high mirror wear-resistant white rubber to obtain the straightened platinum-iridium wire material; (7) Cutting: The straightened platinum-iridium wire material is fixed in a copper tube. The copper tube and the platinum-iridium wire in the copper tube are cut simultaneously by slow wire cutting to obtain a platinum-iridium needle; (8) Secondary heat treatment: The platinum-iridium needle is placed in a limiting groove and heat-treated in a vacuum environment of 300-500℃ for 10-30 minutes. After cooling, the heat-treated platinum-iridium needle is obtained; (9) Coating preparation: The heat-treated platinum-iridium needle is immersed in a coating, then taken out and dried to obtain a platinum-iridium needle with a coating on the surface, namely the implantable platinum-iridium needle.

2. The method for preparing an implantable platinum-iridium needle according to claim 1, characterized in that, The vacuum degree of the vacuum melting in step (1) is 5×10 -3 -5×10 -2 Pa, the temperature of the vacuum melting is 2500-2600℃.

3. The method for preparing an implantable platinum-iridium needle according to claim 1, characterized in that, The water-cooled mold mentioned in step (2) is a water-cooled copper mold.

4. The method for preparing an implantable platinum-iridium needle according to claim 1, characterized in that, The liquid nitrogen mentioned in step (5) is industrial liquid nitrogen with a temperature not higher than -196℃; and / or, the platinum-iridium wire mentioned in step (5) has a tensile strength of 1300-1500MPa and a hardness of 250-300HV.

5. The method for preparing an implantable platinum-iridium needle according to claim 1, characterized in that, The roughness of the straightening module in step (6) is <0.2μm, the straightening pressure is 0.5-1N, and the speed is 1-3m / min; and / or, the straightness of the platinum-iridium wire after straightening in step (6) is 0.05-0.1mm.

6. A method for preparing an implantable platinum-iridium needle according to claim 1, characterized in that, The diameter of the copper tube in step (7) is 0.16-0.31 mm; and / or the length of the platinum-iridium needle in step (7) is 15-30 mm and the straightness is 0.05-0.1 mm.

7. A method for preparing an implantable platinum-iridium needle according to claim 1, characterized in that, The diameter of the limiting groove in step (8) is 0.16-0.31 mm; and / or, the tensile strength of the heat-treated platinum-iridium needle in step (8) is >1000 MPa, and it does not break after being repeatedly bent at 90° 50 times.

8. A method for preparing an implantable platinum-iridium needle according to claim 1, characterized in that, The coating in step (9) is a PTFE water-based coating with a thickness of 15-50 μm; and / or, the drying temperature in step (9) is 150-300℃ and the drying time is 30-120 min.

9. An implantable platinum-iridium needle prepared by the method according to any one of claims 1-8.

10. The application of the implantable platinum-iridium needle of claim 9 in a continuous glucose meter.

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