Degradable composite metal cable and application thereof

Abstract

The invention relates to the technical field of passive implantation medical instruments, in particular to a degradable composite metal cable and application thereof. According to the degradable composite metal cable, the degradable magnesium metal wires and the degradable zinc metal wires are compounded and woven, the mechanical property, the corrosion degradation property and the antibacterial function are improved, meanwhile, good biocompatibility of the degradable composite metal cable can be kept, bone energy supply can be promoted, and wider application requirements can be met; when the cable is applied to internal fixation, the cable can be automatically degraded and disappear in vivo after the internal fixation function is completed, the cable does not need to be taken out through a secondary operation, and potential side effects such as rejection and inflammatory reaction caused by long-term preservation of an implant can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of passive implantable medical devices, and in particular to a degradable composite metal cable and its application. Background Art

[0002] At present, the cable internal fixation systems applied in the clinical field are mainly made of non-degradable stainless steel or titanium alloy, and are mainly used for tying and fixing comminuted fracture sites. Although the above materials have their unique advantages as bone-joining cables, many problems have also emerged in the clinical application process. Stainless steel wire is the earliest developed bone-joining cable material. It not only has good comprehensive mechanical properties but also excellent corrosion resistance. However, subsequent studies have shown that the stainless steel wire used for fixing fractures is prone to breakage during the tightening process at the time of implantation and after implantation, which has an adverse effect on fracture healing.

[0003] To solve the above problems, researchers selected titanium alloy cables with better flexibility to replace stainless steel wires. However, problems such as bone loss induced by the "stress shielding effect" and the need for secondary surgery to remove the implant after fracture healing due to non-degradability have not been solved. Therefore, there is a need for a cable internal fixation system with flexibility, mechanical compatibility, biocompatibility, and degradability in clinical practice.

[0004] For the above reasons, degradable and absorbable materials have begun to be applied in the field of cable internal fixation. The utility model patent with the patent publication number CN204910213U discloses a medical absorbable cable and a medical absorbable cable internal fixation system, which involves orthopedic cables with a diameter of 0.800 - 5.000 mm and are prepared from high molecular weight poly-L-lactic acid. The invention content mentions that the tensile strength of the cable with a diameter of 0.800 - 5.000 mm is 70 - 300 N, which is converted to 15.28 MPa - 139.26 MPa, far lower than the lowest strength of 240 MPa (ISO 5832-2 grade 1) listed in Table 2 of YY / T 0812-2010 Surgical Implants - Metallic Cables and Cords (this standard mainly targets non-degradable stainless steel and titanium alloy). Although degradable polymer materials have excellent biocompatibility and biodegradability, their mechanical properties are weak, and they are prone to breakage during the implantation process or subsequent healing process, and it is difficult to be used as load-bearing bone fixation devices such as bone-joining cables.

[0005] Therefore, the focus of the research and development of the cable internal fixation system has shifted to the field of degradable metals, and there is an urgent need to develop a degradable metal cable that takes into account strength, flexibility, biocompatibility, and biodegradability. The invention patent with the publication number CN111214284B discloses a degradable metal cable internal fixation system and its application. By improving the design of the clamping buckle, this invention patent alleviates stress concentration and cable loosening, enabling the cable internal fixation system to have a longer effective fixation time and ensuring complete bone repair. However, the degradation rate of this degradable metal cable internal fixation system is relatively fast, and one or more gain coatings need to be provided on the inner and outer surfaces of the degradable metal cable, the clamping buckle, and the end head. The tensile strength of this kind of cable is 287.6 MPa - 440.3 MPa, and the elongation after fracture is 11.2% - 4.9%; the corrosion rate of the in vitro corrosion test (immersed in Hank's solution for 10 days) is 0.12 mm / y - 0.29 mm / y, and the in vitro cell test (using the MTT method, extraction ratio 1.25 cm 2 / ml, L-929 cells, MEM containing 10% (V / V) calf serum) shows that the relative proliferation rate of the experimental group cells is 88% - 92%, and the cytotoxicity reaction is grade 1.

[0006] Regarding the problem that the mechanical properties of the cable prepared from the degradable polymer material disclosed in the utility model patent with the publication number CN204910213U are poor, and the cable prepared from the degradable magnesium alloy material disclosed in the invention patent with the publication number CN111214284B, although its mechanical properties basically meet the requirements, has a relatively fast corrosion and degradation rate and requires one or more gain coatings.

[0007] Therefore, it is crucial to provide a degradable composite metal cable with excellent mechanical properties, improved corrosion and degradation performance, and increased antibacterial function. Summary of the Invention

[0008] To solve the above problems, the purpose of the present invention is to provide a degradable composite metal cable and its application. The degradable composite metal cable of the present invention has excellent biodegradability, biocompatibility, good flexibility, sufficient mechanical properties, and osteogenic function, overcoming the disadvantages of non-degradability of existing stainless steel, titanium, and their alloy cables, the insufficient strength of absorbable polymer (such as poly-L-lactic acid) cables, the relatively low strength of pure degradable magnesium alloy cables, and the relatively low biocompatibility and osteogenic ability of pure degradable zinc alloy cables.

[0009] When the degradable composite metal cable of the present invention is applied to internal fixation, it can degrade and disappear in the body by itself after completing the fracture healing function, without the need for a second operation to remove it, greatly reducing the pain and economic burden of the patient, and avoiding the long-term immune rejection and inflammatory reactions caused by the implantation of traditional non-degradable titanium alloy or stainless steel cables. At the same time, during the degradation process, the magnesium ions released by the degradation of the magnesium metal material can fully exert functions such as osteogenesis promotion and immune regulation, and the zinc metal material has a slow degradation rate, high strength, and the released zinc ions have multiple functions such as antibacterial and osteogenesis promotion. Furthermore, the above-mentioned magnesium-zinc metal cable and cable are given high strength and toughness, a degradation rate that meets clinical expectations, good biocompatibility, and osteogenesis promotion function. Therefore, the composite metal cable can be more widely applied and achieve better clinical treatment effects.

[0010] The object of the present invention can be achieved by the following technical solutions:

[0011] The first object of the present invention is to provide a degradable composite metal cable, which is obtained by helically twisting one or more degradable composite metal cables. The degradable composite metal cable is selected from one of the following combined structures:

[0012] (1) The inner layer is a degradable magnesium metal wire, and the outer layer is a degradable zinc metal wire;

[0013] (2) The inner layer is a degradable magnesium metal wire, and the outer layer is alternately arranged degradable magnesium metal wires and degradable zinc metal wires;

[0014] (3) The inner layer is a degradable zinc metal wire, and the outer layer is a degradable magnesium metal wire;

[0015] (4) The inner layer is a degradable zinc metal wire, and the outer layer is alternately arranged degradable magnesium metal wires and degradable zinc metal wires.

[0016] In an embodiment of the present invention, the diameter of the degradable magnesium metal wire is 50 - 200 μm.

[0017] In an embodiment of the present invention, the diameter of the degradable zinc metal wire is 50 - 200 μm.

[0018] In an embodiment of the present invention, the material of the degradable magnesium metal wire is pure magnesium or a magnesium alloy.

[0019] In an embodiment of the present invention, the degradable magnesium metal wire is a Mg-Nd-Zn-Zr metal wire.

[0020] In an embodiment of the present invention, the material of the degradable zinc metal wire is pure zinc or a zinc alloy.

[0021] In an embodiment of the present invention, the degradable zinc metal wire is a Zn-Cu-Li metal wire.

[0022] In one embodiment of the present invention, the degradable composite metal cable includes 1 or 7 degradable composite metal ropes.

[0023] In one embodiment of the present invention, the degradable composite metal rope includes 7 degradable magnesium metal wires, 7 degradable magnesium metal wires, or 7 degradable magnesium metal wires and degradable zinc metal wires.

[0024] The second object of the present invention is to provide an application of the degradable composite metal cable in the preparation of passive implant medical devices.

[0025] The degradable composite metal cable of the present invention is made by composite braiding of degradable magnesium metal wires and degradable zinc metal wires. While achieving the improvement of mechanical properties, corrosion degradation properties, and antibacterial function, it can also maintain its good biocompatibility and osteogenic function, and can meet wider application requirements.

[0026] The degradable composite metal cable of the present invention can give full play to the osteogenic and immunomodulatory functions of the magnesium ions released by the degradation of the degradable magnesium metal wires, as well as the slow degradation rate, high strength, and the antibacterial and osteogenic functions of the zinc ions released by the degradable zinc metal wires. Furthermore, it endows the degradable composite metal cable with high strength and toughness, a degradation rate that meets clinical expectations, and good biocompatibility and osteogenic function.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The degradable composite metal cable of the present invention has excellent flexibility, mechanical compatibility, biocompatibility, and degradation performance that matches the clinical fracture rehabilitation process. The elastic modulus of medical degradable pure magnesium and magnesium alloys is 41 - 45 GPa, and the elastic modulus of medical degradable pure zinc and zinc alloys is 100 - 110 GPa. Therefore, the elastic modulus of the composite metal cable is about 70 GPa, which is closer to the elastic modulus of human bones (7 - 30 GPa) than stainless steel (189 - 205 GPa) and titanium alloy (110 - 117 GPa), can effectively reduce the "stress shielding effect", avoid bone loss caused by it, and has good mechanical compatibility with the human bone.

[0029] (2) The degradable composite metal cable of the present invention has good biocompatibility, does not have a negative impact on cell proliferation, differentiation, and tissue regeneration, and the degradation products do not cause significant negative impacts on human tissues and organs in the short, medium, and long term; moreover, both magnesium and zinc are essential nutrients for the human body, which can catalyze and activate more than 300 known enzyme systems, participate in the storage and transportation of energy within cells, and assist in complex physiological activities such as muscle contraction. Magnesium has excellent biocompatibility and immunomodulatory functions, zinc has good biocompatibility and antibacterial functions, and both magnesium ions and zinc ions can promote bone formation and accelerate fracture healing.

[0030] (3) The degradable composite metal cable of the present invention has good degradable characteristics. When applied in orthopedic surgery, general surgery, etc., it can degrade and disappear in the body by itself within a certain period of time after achieving the curative effect, without the need for a second operation to remove it, greatly reducing the pain and economic burden of the patient. Among them, the degradation rate of degradable pure magnesium and its alloys is about 0.10 mm / y - 0.50 mm / y, the degradation rate of degradable pure zinc and its alloys is about 0.01 mm / y - 0.05 mm / y, and the comprehensive degradation rate of the composite metal cable is between 0.05 mm / y - 0.10 mm / y. The degradation rate can better match the fracture healing speed, and it can be used directly without a coating and show excellent therapeutic effects.

[0031] (4) The degradable composite metal cable of the present invention has excellent mechanical strength and can meet the requirements of bone fixation in load-bearing parts. The yield strength of degradable pure magnesium and its alloys is about 100 MPa - 300 MPa, the yield strength of degradable pure zinc and its alloys is about 100 MPa - 600 MPa, and the strength of the degradable composite metal cable of the present invention can be adjusted within the range of 200 MPa - 600 MPa; generally speaking, the strength of the degradable composite metal cable is about twice that of the degradable magnesium alloy cable, which can meet the mechanical strength during the service period and the safety of internal fixation in clinical applications. Description of the Drawings

[0032] Figure 1 Schematic cross-sectional view of the degradable composite metal cable of Example 1;

[0033] Figure 2 Schematic cross-sectional view of the degradable composite metal cable of Example 2;

[0034] Figure 3 Schematic cross-sectional view of the degradable composite metal cable of Example 3;

[0035] Figure 4 Schematic cross-sectional view of the degradable composite metal cable of Example 4. Detailed Embodiments

[0036] The present invention provides a degradable composite metal cable, which is obtained by helically twisting one or more degradable composite metal ropes. The degradable composite metal rope is selected from one of the following combined structures:

[0037] (1) The inner layer is a degradable magnesium metal wire, and the outer layer is a degradable zinc metal wire;

[0038] (2) The inner layer is a degradable magnesium metal wire, and the outer layer is an alternating arrangement of degradable magnesium metal wires and degradable zinc metal wires;

[0039] (3) The inner layer is a degradable zinc metal wire, and the outer layer is a degradable magnesium metal wire;

[0040] (4) The inner layer is a degradable zinc metal wire, and the outer layer is an alternating arrangement of degradable magnesium metal wires and degradable zinc metal wires.

[0041] Further, the diameter of the degradable magnesium metal wire is 50 - 200 μm;

[0042] The diameter of the degradable zinc metal wire is 50 - 200 μm.

[0043] Further, the material of the degradable magnesium metal wire is pure magnesium or a magnesium alloy;

[0044] Furthermore, the degradable magnesium metal wire is a Mg-Nd-Zn-Zr metal wire.

[0045] Further, the material of the degradable zinc metal wire is pure zinc or a zinc alloy;

[0046] Furthermore, the degradable zinc metal wire is a Zn-Cu-Li metal wire.

[0047] Further, the degradable composite metal cable includes 1 or 7 degradable composite metal ropes.

[0048] Further, the degradable composite metal rope includes 7 degradable magnesium metal wires, 7 degradable magnesium metal wires, or 7 degradable magnesium metal wires and degradable zinc metal wires.

[0049] The present invention provides an application of the degradable composite metal cable in the preparation of passive implantable medical devices.

[0050] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] In the following embodiments, unless otherwise specified, the reagents used are commercially available reagents, and the detection means and methods used are conventional detection means and methods in the art.

[0052] Strength and flexibility: Refer to the standard GB / T 228.1-2010 Metallic materials - Tensile testing - Part 1: Method of test at room temperature. When conducting a tensile test, the gauge length of the cable and cable rope is 254 mm;

[0053] Mechanical compatibility: Elastic modulus is an important physical property of medical metallic materials and one of the important indicators for reference of mechanical compatibility. Generally speaking, it is appropriate that the elastic modulus of metallic materials is slightly greater than that of human cortical bone; References for data of relevant medical materials: Staiger M P, Pietak AM, Huadmai J, et al. Magnesium and its Alloys as Orthopedic Biomaterials[J]. Biomaterials, 2006, 27(9): 1728-1734.

[0054] Biodegradability (corrosion rate): Refer to the standards ASTM G31-2016; GB / T 19291-2003 General principles for corrosion testing of metals and alloys; GB / T 16545-2015 Removal of corrosion products from specimens of metals and alloys.

[0055] Biocompatibility: Refer to the standards GB / T 16886.5-2017 Biological evaluation of medical devices - Part 5: Tests for in vitro cytotoxicity; GB / T 16886.15-2003 Biological evaluation of medical devices - Part 15: Identification and quantification of degradation products from metals and alloys; GB / T 16886.16-2013 Biological evaluation of medical devices - Part 16: Toxicokinetics study design for degradation products and leachables.

[0056] The diameter of any wire in Examples 1-6 is 80 μm.

[0057] Example 1

[0058] This example provides a degradable composite metal cable (with a low degradation rate and high mechanical properties), which is composed of 1 degradable composite metal cable rope. The inner layer of the degradable composite metal cable rope is 1 pure magnesium wire, and the outer layer is 6 pure zinc wires, and is obtained by helically twisting the above 7 wires (as Figure 1 shown).

[0059] Technical effect evaluation: The tensile strength of this kind of cable is 430 MPa, and the elongation after fracture is 21.2%; The corrosion rate of the in vitro corrosion test (immersed in Hank's solution for 10 days) is 0.02 mm / y; The in vitro cell test (using the MTT method, extraction ratio 1.25 cm 2 / ml, L-929 cells, MEM containing 10% (V / V) calf serum) showed that the relative proliferation rate of the experimental group cells was 86%, and the cytotoxicity reaction was grade 1; it was used for cable internal fixation system and had good healing after implantation. No cable ectopia, fracture or shedding was found within 6 months after implantation, and the complete degradation time was about 26 months.

[0060] Example 2

[0061] This example provides a degradable composite metal cable (with high bioactivity), which consists of 1 degradable composite metal cable. The inner layer of the degradable composite metal cable is 1 pure zinc wire, and the outer layer is 6 pure magnesium wires. And the above 7 wires are helically twisted to obtain (as Figure 2 shown).

[0062] Technical effect evaluation: The tensile strength of this kind of cable is 376 MPa, and the elongation after fracture is 15.1%; the corrosion rate of the in vitro corrosion test (immersed in Hank's solution for 10 days) is 0.09 mm / y; the in vitro cell test (using the MTT method, the extraction ratio is 1.25 cm 2 / ml, L-929 cells, MEM containing 10% (V / V) calf serum) showed that the relative proliferation rate of the experimental group cells was 93%, and the cytotoxicity reaction was grade 1; it was used for cable internal fixation system and had good healing after implantation. No cable ectopia, fracture or shedding was found within 6 months after implantation, and the complete degradation time was about 20 months.

[0063] Example 3

[0064] This example provides a degradable composite metal cable (with both low degradation rate, high mechanical properties and high biocompatibility), which consists of 1 degradable composite metal cable. The inner layer of the degradable composite metal cable is 1 pure zinc wire, and the outer layer is 3 pure magnesium wires and 3 pure zinc wires arranged at intervals. And the above 7 wires are helically twisted to obtain (as Figure 3 shown).

[0065] Technical effect evaluation: The tensile strength of this kind of cable is 412 MPa, and the elongation after fracture is 19.7%; the corrosion rate of the in vitro corrosion test (immersed in Hank's solution for 10 days) is 0.06 mm / y; the in vitro cell test (using the MTT method, the extraction ratio is 1.25 cm 2 / ml, L-929 cells, MEM containing 10% (V / V) calf serum) showed that the relative proliferation rate of the experimental group cells was 92%, and the cytotoxicity reaction was grade 1; it was used for cable internal fixation system and had good healing after implantation. No cable ectopia, fracture or shedding was found within 6 months after implantation, and the complete degradation time was about 25 months.

[0066] Example 4

[0067] This embodiment provides a degradable composite metal cable (with both low degradation rate, high mechanical properties and high biocompatibility), which is composed of 1 degradable composite metal cable. The inner layer of the degradable composite metal cable is 1 pure magnesium wire, and the outer layer is 3 pure magnesium wires and 3 pure zinc wires arranged at intervals, and is obtained by helically twisting the above 7 wires (as Figure 4 shown).

[0068] Technical effect evaluation: The tensile strength of this cable is 398 MPa, and the elongation after fracture is 18.2%; the corrosion rate of the in vitro corrosion test (immersed in Hank's solution for 10 days) is 0.07 mm / y; the in vitro cell test (using the MTT method, the extraction ratio is 1.25 cm 2 / ml, L-929 cells, MEM containing 10% (V / V) calf serum) shows that the relative proliferation rate of the experimental group cells is 92%, and the cytotoxicity reaction is grade 1; it is used for good healing after the cable internal fixation system is implanted. No cable ectopia, fracture or shedding is seen within 6 months of implantation, and the complete degradation time is about 25 months.

[0069] Example 5

[0070] This embodiment provides a degradable composite metal cable, which is composed of 1 degradable composite metal cable. The inner layer of the degradable composite metal cable is 1 Mg-Nd-Zn-Zr alloy wire, and the outer layer is 3 Mg-Nd-Zn-Zr alloy wires and 3 Zn-Cu-Li alloy wires arranged at intervals, and is obtained by helically twisting the above 7 wires.

[0071] Technical effect evaluation: The tensile strength of this cable is 496 MPa, and the elongation after fracture is 29.2%; the corrosion rate of the in vitro corrosion test (immersed in Hank's solution for 10 days) is 0.10 mm / y; the in vitro cell test (using the MTT method, the extraction ratio is 1.25 cm 2 / ml, L-929 cells, MEM containing 10% (V / V) calf serum) shows that the relative proliferation rate of the experimental group cells is 91%, and the cytotoxicity reaction is grade 1; it is used for good healing after the cable internal fixation system is implanted. No cable ectopia, fracture or shedding is seen within 6 months of implantation, and the complete degradation time is about 19 months.

[0072] Example 6

[0073] This embodiment provides a degradable composite metal cable, which is composed of 1 degradable composite metal cable. The inner layer of the degradable composite metal cable is 1 Zn-Cu-Li alloy wire, and the outer layer is 3 Mg-Nd-Zn-Zr alloy wires and 3 Zn-Cu-Li alloy wires arranged at intervals, and is obtained by helically twisting the above 7 wires.

[0074] Technical effect evaluation: The tensile strength of this kind of cable is 525 MPa, and the elongation after fracture is 34.8%; the corrosion rate of the in vitro corrosion test (immersed in Hank's solution for 10 days) is 0.09 mm / y; the in vitro cell test (using the MTT method, the extraction ratio is 1.25 cm 2 / ml, L-929 cells, MEM containing 10% (V / V) calf serum) shows that the relative proliferation rate of the experimental group cells is 90.5%, and the cytotoxic reaction is grade 1; after being used for cable internal fixation system implantation, the healing is good, and no cable ectopia, fracture or shedding is seen within 6 months of implantation, and the complete degradation time is about 19 months.

[0075] Comparative Example 1

[0076] This comparative example provides a degradable composite metal cable, which is composed of 1 degradable composite metal cable rope. The inner layer of the degradable composite metal cable rope is 1 pure magnesium wire, and the outer layer is 6 pure magnesium wires, and the above 7 wires are helically twisted to obtain.

[0077] Technical effect evaluation: The tensile strength of this kind of cable is 287.6 MPa, and the elongation after fracture is 21.2%; the corrosion rate of the in vitro corrosion test (immersed in Hank's solution for 10 days) is 0.12 mm / y; the in vitro cell test (using the MTT method, the extraction ratio is 1.25 cm 2 / ml, L-929 cells, MEM containing 10% (V / V) calf serum) shows that the relative proliferation rate of the experimental group cells is 92%, and the cytotoxic reaction is grade 1; after being used for cable internal fixation system implantation, the healing is good, no cable ectopia or shedding is seen, and the complete degradation time is about 18 months.

[0078] Comparative Example 2

[0079] This comparative example provides a degradable composite metal cable, which is composed of 1 degradable composite metal cable rope. The inner layer of the degradable composite metal cable rope is 1 pure zinc wire, and the outer layer is 6 pure zinc wires, and the above 7 wires are helically twisted to obtain.

[0080] Technical effect evaluation: The tensile strength of this kind of cable is 446 MPa, and the elongation after fracture is 21.3%; the corrosion rate of the in vitro corrosion test (immersed in Hank's solution for 10 days) is 0.02 mm / y; the in vitro cell test (using the MTT method, the extraction ratio is 1.25 cm 2 / ml, L-929 cells, MEM containing 10% (V / V) calf serum) shows that the relative proliferation rate of the experimental group cells is 74%, and the cytotoxic reaction is grade 2; after being used for cable internal fixation system implantation, the healing is good, no cable ectopia or shedding is seen, and the complete degradation time is about 28 months.

[0081] As can be seen from Comprehensive Examples 1, 2, 3, 4 and Comparative Example 1, for the composite metal cable obtained by helically twisting the degradable pure zinc wire and the degradable pure magnesium wire, the mechanical strength and the tensile elongation can be significantly improved simultaneously, the degradation rate is significantly decreased, and the complete degradation time is prolonged; the biocompatibility only slightly decreases in Example 1, but does not decrease in other examples, and even slightly increases in Example 2; the comprehensive performance of the composite metal cable obtained by helically twisting the degradable pure zinc wire and the degradable pure magnesium wire has been significantly improved compared with the comprehensive performance of the cable made entirely of degradable pure magnesium wire.

[0082] As can be seen from Comprehensive Examples 1, 2, 3, 4 and Comparative Example 2, for the composite metal cable obtained by helically twisting the degradable pure zinc wire and the degradable pure magnesium wire, although the mechanical strength of the composite metal cable slightly decreases compared with the pure zinc cable, it still has high safety after implantation; although the degradation rate slightly increases, the shortening of the complete degradation time is not obvious, and it still has high safety after implantation. Moreover, a large number of previous research reports have confirmed that the degradation rate of magnesium and its alloys is relatively fast when used as implants, while the degradation rate of zinc and its alloys is slightly slower when used as implants. Therefore, the slight increase in the degradation rate is actually beneficial; at the same time, the biocompatibility is significantly improved, from cytotoxicity level 2 to cytotoxicity level 1; generally speaking, the technical evaluation effect of the composite wire is better.

[0083] It should be noted that it is generally considered that serious galvanic corrosion will occur when two different metals are placed together; therefore, for materials usually used in a corrosive environment, the composite method is generally avoided. However, in the present invention, during the degradation process, due to the covering and protection of the degradation products, the galvanic corrosion effect is not obvious. For example, the composite metal cables in Example 1 and Example 2 do not show the galvanic corrosion effect because the outer wires are of the same kind; for the composite metal cables in Example 3 and Example 4, except for showing a certain galvanic corrosion effect in the first few hours, the galvanic corrosion effect is alleviated and inhibited due to the covering of the corrosion degradation product layer in the later stage.

[0084] Six typical specific examples of the present invention are described above. In addition, other degradable magnesium alloys and zinc alloy materials, as well as degradable pure iron or iron alloy materials can also be selected for composite helical twisting to prepare the degradable composite metal cable; the degradable composite cable can also select combinations such as 1 (number of cables) × 3 (number of wires), 1×7, 1×19, 1×37, 3×7, 7×7, 7×19, etc.

[0085] The above description of the embodiments is provided to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and all improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the interpretation of the present invention should be within the protection scope of the present invention.

Claims

1. A degradable composite metal cable, characterized in that, it is obtained by helically twisting one or more degradable composite metal ropes, and the degradable composite metal rope is selected from one of the following combined structures: (1) The inner layer is a degradable magnesium metal wire, and the outer layer is a degradable zinc metal wire; (2) The inner layer is a degradable magnesium metal wire, and the outer layer is an alternating arrangement of degradable magnesium metal wires and degradable zinc metal wires; (3) The inner layer is a degradable zinc metal wire, and the outer layer is a degradable magnesium metal wire; (4) The inner layer is a degradable zinc metal wire, and the outer layer is an alternating arrangement of degradable magnesium metal wires and degradable zinc metal wires.

2. The degradable composite metal cable according to claim 1, characterized in that, the diameter of the degradable magnesium metal wire is 50-200 μm.

3. The degradable composite metal cable according to claim 1, characterized in that, the diameter of the degradable zinc metal wire is 50-200 μm.

4. The degradable composite metal cable according to claim 1, characterized in that, the material of the degradable magnesium metal wire is pure magnesium or a magnesium alloy.

5. The degradable composite metal cable according to claim 4, characterized in that, the degradable magnesium metal wire is a Mg-Nd-Zn-Zr metal wire.

6. The degradable composite metal cable according to claim 1, characterized in that, the material of the degradable zinc metal wire is pure zinc or a zinc alloy.

7. The degradable composite metal cable according to claim 6, characterized in that, the degradable zinc metal wire is a Zn-Cu-Li metal wire.

8. The degradable composite metal cable according to claim 1, characterized in that, the degradable composite metal cable includes 1 or 7 degradable composite metal ropes.

9. The degradable composite metal cable according to claim 8, characterized in that, the degradable composite metal rope includes 7 degradable magnesium metal wires, 7 degradable magnesium metal wires, or 7 degradable magnesium metal wires and degradable zinc metal wires.

10. Use of the degradable composite metal cable according to any one of claims 1-9 in the preparation of passive implantable medical devices.

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