Magnesium alloy gun core for rotator cuff repair surgery suture gun and preparation method of magnesium alloy gun core

Abstract

The invention discloses a magnesium alloy gun core for a rotator cuff repair surgery suture gun and a preparation method of the magnesium alloy gun core. The gun core comprises a hard needle part, a transition area and a soft needle part, the gun core is made of Mg-Li-Sc-Ti-MBene alloy and comprises the following elements in percentage by weight: 4wt.% of Li, 10wt.% of Sc, 2wt.% of Ti, 1.5 wt.% of MBene and the balance of Mg in the hard needle part; the soft needle part contains 20 weight percent of Li, 2 weight percent of Sc, 0.5 weight percent of Ti, 0.5 weight percent of MBene and the balance of Mg; the transition area is located between the hard needle part and the soft needle part, and all element components are distributed in a gradually changing mode. The gun core is prepared through an alloy casting method and a gradient extrusion method and has good mechanical performance, biocompatibility and degradability, the efficiency and safety of a rotator cuff repair operation are improved, and meanwhile the probability that a secondary operation is needed is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of medical device material preparation and relates to a magnesium alloy gun core for a rotator cuff repair surgery suture gun and a preparation method thereof. BACKGROUND

[0002] Rotator cuff suture is a surgical method to restore the integrity of the torn tendon by suturing. Currently, in rotator cuff repair surgery, instruments such as suture guns and suture anchors are often used to fix the damaged rotator cuff tissue. The suture instruments and materials used in rotator cuff suture are crucial to the surgical outcome. Suture instruments are usually used to accurately place sutures on torn tendons and bones. The suture gun used in rotator cuff repair surgery is composed of a gun body and a gun core. The existing suture gun core is mostly made of stainless steel or titanium alloy, but its structure is thin and brittle. The surgical situation is complex and variable, and if the gun core is accidentally broken in the body, it is not easy for medical personnel to remove it, and the stainless steel and other materials are not easy to degrade in the body, which will affect the rotator cuff and its surrounding tissues.

[0003] In view of the problems of high risk of fracture and poor biocompatibility of the existing suture gun core material, it is urgent to develop a new material with high strength and good biodegradability. Magnesium-based composite materials have become a promising alternative material due to their degradable properties and lightweight advantages. However, increasing the hardness of magnesium composite materials usually requires increasing the grain boundary strengthening or precipitated phase, which often leads to a decrease in toughness. The increase in hardness is usually accompanied by grain refinement or an increase in second-phase particles, which hinders dislocation motion, thereby increasing strength, but also limits the material's plastic deformation ability, reducing toughness. Therefore, when optimizing the performance of magnesium composite materials, a balance between hardness and toughness needs to be found.

[0004] Chinese invention patent application No. 201920284701.0 discloses an instrument for rotator cuff repair surgery, which integrates tissue grabbing and threading functions, simplifies operation, reduces the number of instruments and improves surgical efficiency through innovative structural design. However, this patent lacks a description of the material of the instrument, and stainless steel is commonly used as the material for rotator cuff repair surgery instruments on the market. The needle core soft needle part is extremely prone to breaking during surgery due to its special structure, so it will face the risk of secondary surgery to remove the needle core soft needle part.

[0005] The document“Metals”2024, 14, 288 discloses a biodegradable suture anchor of Mg-2.8Nd-0.2Zn-0.4Zr (wt.%) alloy for ligament-bone fixation in rotator cuff surgery, and studies its mechanical properties and in vitro corrosion behavior. Although magnesium alloy has good degradation and biocompatibility, its corrosion resistance is still limited, hydrogen is generated after implantation into the human body, affecting the normal function of the tissue and the healing process, and the mechanical properties gradually decrease with degradation, and the rotator cuff fixation effect is weakened, so there are still deficiencies in the use of magnesium alloy materials for rotator cuff tendon fixation.

[0006] In summary, the main shortcomings of the current rotator cuff repair surgical instruments are:

[0007] First, the rotator cuff suture gun core is prone to breakage during use;

[0008] Second, the traditional medical magnesium alloy material is not suitable for the rotator cuff suture gun core;

[0009] Third, the stainless steel material used in rotator cuff repair surgery can cause rejection reactions in some patients.

[0010] Based on this, the present application aims to prepare a suture gun core with good mechanical properties and biocompatibility, improve the safety and efficiency of rotator cuff repair surgery, and reduce the risk of surgical failure caused by the breakage of the gun core in the human body. SUMMARY

[0011] To solve the above technical problems, the present application provides a magnesium alloy gun core for rotator cuff repair surgery and a preparation method thereof. The gun core comprises a hard needle part, a transition zone and a soft needle part. The gun core material is Mg-Li-Sc-Ti@MBene alloy. The content of each part element is as follows: the hard needle part contains Li 4wt.%, Sc 10wt.%, Ti 2wt.%, MBene 1.5wt.%, and the balance is Mg; the soft needle part contains Li 20wt.%, Sc 2wt.%, Ti 0.5wt.%, MBene 0.5wt.%, and the balance is Mg; the transition zone is located between the hard needle part and the soft needle part, and each element composition is gradually distributed. The gun core is prepared by alloy casting method and gradient extrusion method, which has good mechanical properties, biocompatibility and degradability, improves the efficiency and safety of rotator cuff repair surgery, and reduces the probability of secondary surgery.

[0012] To achieve the above purpose, the technical scheme adopted by the present application is:

[0013] The magnesium alloy gun core for a rotator cuff repair surgery stitching gun comprises a hard needle part, a transition zone and a soft needle part; the diameter of the hard needle part is 4-6mm, the length is 200-220mm, and the shape is a thin rod; the diameter of the transition zone is 2-6mm, the length is 20-30mm, and the shape is a ladder; the width of the soft needle part is 2-4mm, the length is 50-60mm, the thickness is 0.5mm, and the shape is a sheet;

[0014] The gun core material is Mg-Li-Sc-Ti@MBene alloy; the hard needle part contains Li 4wt.%, Sc 10wt.%, Ti 2wt.%, MBene 1.5wt.%, and the balance is Mg; the soft needle part contains Li 20wt.%, Sc 2wt.%, Ti 0.5wt.%, MBene 0.5wt.%, and the balance is Mg; the transition zone is the area where the hard needle part transitions to the soft needle part, and when the hard needle part points to the soft needle part, the Li content gradually increases from 4wt.% to 20wt.%, the Sc content gradually decreases from 10wt.% to 2wt.%, the Ti content gradually decreases from 2wt.% to 0.5wt.%, the MBene content gradually decreases from 1.5wt.% to 0.5wt.%, and the balance is Mg.

[0015] The top end of the hard needle part of the rotator cuff stitching gun gun core is provided with a groove, the groove is designed as a mortise and tenon structure, the gun core is fixed in the interior of the gun body of the rotator cuff stitching gun, the transition zone is ladder-shaped and connects the hard needle part and the soft needle part, the soft needle part is sheet-shaped, the tail part is provided with a needle head, the bottom of the needle head is a sharp end, the sharp end can pierce the skin, rotator cuff tendon and bone tissue of a human body, two grooves are arranged above the sharp end, and the grooves are used for winding of surgical sutures.

[0016] The addition of Li element in the application reduces the density of the magnesium composite material and improves the toughness, and low Li content forms an α-Mg solid solution in the Mg matrix to provide basic toughness; the addition of Sc element can improve the hardness of the magnesium composite material through second phase strengthening and solid solution strengthening, Sc forms Mg-Sc intermetallic compound with Mg and improves the hardness and strength of the hard needle part through solid solution strengthening and precipitation strengthening, and the scandium oxide formed during corrosion can form a passivation layer on the surface of the magnesium composite material, thereby improving the corrosion resistance of the magnesium composite material; the addition of Ti element refines the grains to form a fine-grained structure, and reacts with Mg to form Mg-Ti precipitates to further strengthen the matrix. At the same time, the fine-grained effect of Ti provides a more uniform and smaller distribution site for the precipitates of Sc, and the passivation layer of Sc protects the magnesium matrix optimized by the joint action of Li and Ti, and the addition of Li and Ti does not harm the ability of Sc to form an effective passivation layer. This effect ensures that the material not only has excellent mechanical properties, but also has good corrosion resistance. The introduction of MBene enhances the interfacial bonding force of the material, inhibits local corrosion during degradation, and at the same time improves the mechanical properties and biological safety. MBene, as a two-dimensional nanosheet, is uniformly dispersed in the magnesium composite material matrix, effectively hinders dislocation movement through second phase strengthening and grain boundary pinning effect, and forms a coherent interface with the Mg-Sc phase to reduce the tendency of galvanic corrosion at the grain boundary. The introduction of MBene nanosheets enhances the interfacial bonding force of the material, so that the hardness of the alloy can reach more than 185HV, meeting the high strength requirement of bone puncture, in addition, the lamellar structure of MBene can absorb energy and inhibit crack propagation, which can improve the flexibility of the soft needle part.

[0017] In the present invention, the content of each element is the key to achieving good mechanical properties and biocompatibility of the magnesium alloy gun core. The content of the hard needle part of the gun core is Li 4wt.%, Sc 10wt.%, Ti 2wt.%, MBene 1.5wt.%, and the balance is Mg, which ensures that the hard needle part of the gun core meets the hardness requirements of the rotator cuff surgery operation; if the content of each element is increased and the Mg content is reduced, the brittleness of the hard needle part will increase due to the reduction of the solid solution strengthening phase of Mg, and it will be more likely to break; if the content of each element is reduced and the Mg content is increased, a pure magnesium layer will be formed at the grain boundary, resulting in more likely dislocation movement, which will reduce the hardness of the hard needle part and thus cause the gun core to break; the content of the soft needle part of the gun core is Li 20wt.%, Sc 2wt.%, Ti 0.5wt.%, MBene 0.5wt.%, and the balance is Mg. This content can ensure that the soft needle part of the gun core meets the hardness requirements of bone puncture, and at the same time has high toughness to ensure that the gun core can operate in the bone joint; if the content of each element is increased and the Mg content is reduced, the second phase between the metals is prone to generate crack sources, which will reduce the toughness of the soft needle part and make it more likely to break in the human body; if the content of each element is reduced and the Mg content is increased, a pure magnesium layer will be formed at the grain boundary, making dislocation movement more likely to occur, which will reduce the hardness of the soft needle part and make bone puncture impossible.

[0018] The present invention also provides a method for preparing a magnesium alloy gun core for a rotator cuff repair surgery suture gun, which is carried out in the following steps in sequence:

[0019] S1. Preparation of MBene

[0020] Weigh (Mo 2 / 3 Y 1 / 3 )2AlB2 and add 40wt.% HF solution, etch at 35-60℃ for 16h, wash with deionized water 3-5 times, add 10-20mL 2mol / L TMAOH solution, stir at 3-5℃ for 1-5h, then wash with anhydrous ethanol 3-5 times, centrifuge at 3500-10500rpm for 15-30min, and freeze-dry to obtain MBene;

[0021] S2. Preparation of Mg-Li-Sc-Ti@MBene alloy

[0022] Under an argon atmosphere, Mg powder, Li powder, Sc powder, Ti powder, and MBene powder were evenly spread in a trough crucible according to the atomic ratio of each region. 1 to 10 g of a binder was added. After cold isostatic pressing at room temperature, the mixture was placed in a muffle furnace for calcination to obtain a Mg-Li-Sc-Ti@MBene alloy.

[0023] S3. Prepare the suture gun core

[0024] The Mg-Li-Sc-Ti@MBene alloy is cut into a cylinder with a diameter of 275-310 mm, annealed at 250-300 DEG C for 0.5-3 h, then placed in an extrusion cylinder for extrusion, water-cooled at 20-30 DEG C for 20-40 min, taken out, and placed in a numerical control machine tool to process into the shape of a suture gun core, cleaned with anhydrous ethanol for 3-5 min to remove surface impurities, and the suture gun core is obtained.

[0025] As a limitation of the preparation method of the application, in step S1, the (Mo 2 / 3 Y 1 / 3 )2AlB2 and the mass fraction of the 40wt. % HF solution is (1-2) :(10-20) g / mL.

[0026] As another limitation of the preparation method of the application, in step S1, the temperature during freeze-drying is -10-5 DEG C, and the time is 12-36 h.

[0027] As a third limitation of the preparation method of the application, in step S2, the binder is one or more of phenolic resin, magnesium aluminum silicate, polyvinyl chloride, 107 glue, white latex, and sodium silicate.

[0028] As a fourth limitation of the preparation method of the application, in step S2, the pressure during cold isostatic pressing is 200-350 MPa, and the processing time is 40-60 min.

[0029] As a fifth limitation of the preparation method of the application, in step S2, the calcination temperature is 700-850 DEG C, the time is 40-60 min, and the heating rate is 2-5 DEG C / min.

[0030] In the present application, calcination of the alloy affects its mechanical properties. When the calcination temperature is 700-850 DEG C, the powder particles will rearrange, reducing the gap between the particles, thereby increasing the density of the material. If the temperature is greater than 850 DEG C, the premature close combination between particles will affect the formation of the solid solution, thereby causing the material to have poor mechanical properties. If the temperature is less than 700 DEG C, the contact and diffusion rate between particles will be greatly reduced, resulting in a porous material, which will cause the material to have poor mechanical properties and be easily corroded, affecting the surgical process. Holding for 40-60 min helps to gradually increase the contact area between particles and reduce porosity. If the holding time is greater than 60 min, the bonding force between particles is too strong, causing deformation between particles and affecting the performance of the magnesium alloy material. If the holding time is less than 40 min, the bonding force between particles is too weak, causing the particles to not be closely combined and increasing the gap of the material. The temperature rising rate of 2-5 DEG C / min is to ensure that the temperature rises gradually and uniformly, avoiding excessive thermal expansion stress. If the temperature rising rate is greater than 5 DEG C / min, the thermal stress in the material will be too large, causing cracking or deformation. If the temperature rising rate is less than 2 DEG C / min, the temperature rising time is too long, increasing the production time and energy consumption.

[0031] As the sixth limitation of the preparation method of the present application, in step S3, the extrusion ratio is 10-16, the extrusion rate is 1-5 m / min, and the temperature is 300-400 DEG C.

[0032] The above technical solutions of the present application are closely related and interact with each other as a whole, which jointly determines the morphology characteristics and performance of the product.

[0033] The above technical solutions have the following advantages or beneficial effects:

[0034] 1. The magnesium alloy suture gun core prepared by the present application has good biocompatibility and does not produce rejection reaction with the human body during the operation process, and reduces the risk of operation failure caused by the fracture of the gun core in the human body;

[0035] 2. The present application realizes the smooth transition of the mechanical properties of the transition zone through gradient design, so as to improve the overall performance of the gun core and the safety of the operation;

[0036] 3. The magnesium alloy suture gun core prepared by the present application has a tensile strength of the hard needle part ≥340 MPa and a microhardness ≥185 HV, which meets the demand of puncturing bone; the soft needle part has high elongation and fatigue resistance, which is suitable for repeated bending of tendon suture; the transition zone can effectively inhibit the fracture risk caused by interface stress concentration; the gradient performance is realized through phase change, which is highly matched with the mechanical gradient of bone-tendon-skin, thereby improving the success rate of operation;

[0037] 4、The preparation method is simple, the process is easy to control, and is suitable for large-scale industrial production.

[0038] The application is suitable for preparing a magnesium alloy core of a suture gun.

[0039] The technical solutions of the application will be further described in detail below with reference to the drawings and specific embodiments of the specification. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 A microstructure diagram of the suture gun magnesium alloy core prepared in Example 1 of the application;

[0041] Figure 2 A scanning electron microscope diagram of the MBene nanosheet prepared in step S1 of Example 1 of the application;

[0042] Figure 3 A real object diagram of the suture gun magnesium alloy core prepared in Example 1 of the application;

[0043] Figure 4 A longitudinal section diagram of the suture gun magnesium alloy core prepared in Example 1 of the application;

[0044] Figure 5 A composition analysis diagram of the suture gun core prepared in Example 1 of the application at four points, wherein: the point A is located at the hard needle part, the points B and C are located at the transition zone, and the point D is located at the soft needle part;

[0045] Figure 6 A corrosion morphology diagram of the suture gun core prepared in Example 1 of the application in Hank's solution (simulating human body fluid) for 1-6 days. DETAILED DESCRIPTION

[0046] The following examples are only a part of the embodiments of the application, rather than all the embodiments. Therefore, the detailed description of the embodiments of the application provided below is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. Based on the embodiments of the application, all other embodiments obtained by those skilled in the art without creative work are within the protection scope of the application.

[0047] In the application, all the equipment and raw materials, etc. can be purchased from the market or commonly used in the industry, unless otherwise specified. The methods in the following examples are all conventional methods in the art, unless otherwise specified.

[0048] Example 1

[0049] The embodiment prepares a magnesium alloy gun core for a rotator cuff repair surgery suture gun. The gun core comprises a hard needle part, a transition zone and a soft needle part. The hard needle part has a diameter of 4 mm, a length of 200 mm and a shape of a thin rod; the transition zone has a diameter of 2 mm, a length of 20 mm and a shape of a ladder; and the soft needle part has a width of 2 mm, a length of 55 mm, a thickness of 0.5 mm and a shape of a sheet. The magnesium alloy gun core comprises Li 4wt.%, Sc 10wt.%, Ti 2wt.%, MBene 1.5wt.% and the balance of Mg in the hard needle part; Li 20wt.%, Sc 2wt.%, Ti 0.5wt.%, MBene 0.5wt.% and the balance of Mg in the soft needle part; and the content of Li gradually increases from 4wt.% to 20wt.%, the content of Sc gradually decreases from 10wt.% to 2wt.%, the content of Ti gradually decreases from 2wt.% to 0.5wt.% and the content of MBene gradually decreases from 1.5wt.% to 0.5wt.% in the transition zone, with the balance of Mg. The gun core preparation process and steps are as follows:

[0050] S1, preparation of MBene

[0051] 1g (Mo 2 / 3 Y 1 / 3 )2AlB2 is weighed and added to 10mL of a 40wt.% HF solution. Etching is carried out at 35℃ for 16h. After washing with deionized water for 3 times, 10mL of 2mol / L TMAOH solution is added, stirring is carried out at 3℃ for 1h. After washing with anhydrous ethanol for 3 times, centrifugation is carried out at a speed of 3500rpm for 30min, and freeze-drying is carried out at -10℃ for 12h, to obtain MBene;

[0052] S2, preparation of Mg-Li-Sc-Ti@MBene alloy

[0053] Under an argon atmosphere, Mg powder, Li powder, Sc powder, Ti powder and MBene powder are uniformly laid in a groove crucible according to the atomic ratio of each region (the hard needle part is melted and cast in the front part of the crucible, the transition zone is melted and cast in the middle part, and the soft needle part is melted and cast in the rear part, and the powder laying is controlled by AFS-M20X). 1g of phenolic resin is added, cold isostatic pressing is carried out at room temperature and 200MPa for 40min, and then it is placed in a muffle furnace, heated from room temperature to 700℃ at a rate of 2℃ / min, and calcined for 40min, to obtain a Mg-Li-Sc-Ti@MBene alloy;

[0054] S3, preparation of suture gun core

[0055] The Mg-Li-Sc-Ti@MBene alloy was cut into a 275 mm cylinder, annealed at 250℃ for 0.5 h, then placed in an extrusion cylinder for extrusion (extrusion ratio of 10, extrusion rate of 1 m / min, extrusion temperature of 300℃), and then taken out after water cooling at 20℃ for 20 min, and placed in a numerical control machine tool to process the shape of the suture gun core, and then cleaned with anhydrous ethanol for 3 min to remove surface impurities, to obtain the suture gun core.

[0056] Example 2

[0057] In this embodiment, a magnesium alloy gun core for a rotator cuff repair surgery suture gun is prepared, which includes a hard needle part, a transition zone and a soft needle part. The hard needle part has a diameter of 5 mm, a length of 210 mm and a shape of a thin rod; the transition zone has a diameter of 4 mm, a length of 25 mm and a shape of a ladder; and the soft needle part has a width of 3 mm, a length of 50 mm, a thickness of 0.5 mm and a shape of a sheet. The hard needle part contains Li 4wt.%, Sc 10wt.%, Ti 2wt.%, MBene 1.5wt.%, and the balance is Mg; the soft needle part contains Li 20wt.%, Sc 2wt.%, Ti 0.5wt.%, MBene 0.5wt.%, and the balance is Mg; the transition zone gradually increases the content of Li from 4wt.% to 20wt.%, gradually reduces the content of Sc from 10wt.% to 2wt.%, gradually reduces the content of Ti from 2wt.% to 0.5wt.%, gradually reduces the content of MBene from 1.5wt.% to 0.5wt.%, and the balance is Mg. The gun core preparation process and steps are as follows:

[0058] S1, preparation of MBene

[0059] 1.5 g (Mo 2 / 3 Y 1 / 3 )2AlB2 was weighed and added to 15 mL of a 40wt.% HF solution, etched at 50℃ for 16 h, washed with deionized water 4 times, then added to 15 mL of a 2 mol / L TMAOH solution, stirred at 4℃ for 3 h, then washed with anhydrous ethanol 4 times, centrifuged at a speed of 9500 rpm for 20 min, and freeze-dried at 0℃ for 24 h to obtain MBene;

[0060] S2, preparation of Mg-Li-Sc-Ti@MBene alloy

[0061] Under argon atmosphere, Mg powder, Li powder, Sc powder, Ti powder and MBene powder were uniformly laid in the groove crucible according to the atomic ratio of each region (crucible front part, middle part, rear part, through AFS-M20X control powder laying), 5g magnesium aluminum silicate was added, cold isostatic pressing was carried out at room temperature, 300MPa for 50min, then it was placed in a muffle furnace, heated from room temperature to 800℃ at a rate of 3℃ / min, calcined for 50min, to obtain Mg-Li-Sc-Ti@MBene alloy;

[0062] S3, preparing a suture gun core

[0063] The Mg-Li-Sc-Ti@MBene alloy was cut into a 285mm cylinder, annealed at 275℃ for 1h, then placed in an extrusion cylinder for extrusion (extrusion ratio 14, extrusion rate 3m / min, extrusion temperature 350℃), the alloy was taken out after water cooling at 25℃ for 30min, and placed in a numerical control machine tool to process the shape of the suture gun core, and the surface impurities were cleaned with anhydrous ethanol for 4min to obtain the suture gun core.

[0064] Example 3

[0065] A magnesium alloy core for a rotator cuff repair surgery suture gun was prepared in this example. The core includes a hard needle part, a transition zone and a soft needle part. The hard needle part has a diameter of 6mm, a length of 220mm and a shape of a thin rod; the transition zone has a diameter of 6mm, a length of 30mm and a shape of a ladder; the soft needle part has a width of 4mm, a length of 60mm, a thickness of 0.5mm and a shape of a sheet. The hard needle part contains Li 4wt.%, Sc 10wt.%, Ti 2wt.%, MBene 1.5wt.%, and the balance is Mg; the soft needle part contains Li 20wt.%, Sc 2wt.%, Ti 0.5wt.%, MBene 0.5wt.%, and the balance is Mg; the transition zone gradually increases the content of Li from 4wt.% to 20wt.%, gradually reduces the content of Sc from 10wt.% to 2wt.%, gradually reduces the content of Ti from 2wt.% to 0.5wt.%, gradually reduces the content of MBene from 1.5wt.% to 0.5wt.%, and the balance is Mg. The core preparation process and steps are as follows:

[0066] S1, preparing MBene

[0067] 2g (Mo 2 / 3 Y 1 / 3)2AlB2and 20 mL of 40 wt.% HF solution was added, etched at 60℃ for 16 h, washed with deionized water for 5 times, then 20 mL of 2 mol / L TMAOH solution was added, stirred at 5℃ for 5 h, then washed with anhydrous ethanol for 5 times, centrifuged at a speed of 10500 rpm for 15 min, and freeze-dried at 5℃ for 36 h to obtain MBene;

[0068] S2, preparation of Mg-Li-Sc-Ti@MBene alloy

[0069] Under an argon atmosphere, Mg powder, Li powder, Sc powder, Ti powder and MBene powder were uniformly laid in a crucible according to the atomic ratio of each region (crucible front part, middle part, rear part, through AFS-M20X control powder laying), 10 g of polyvinyl chloride was added, cold isostatic pressing was carried out at room temperature and 350 MPa for 60 min, then it was placed in a muffle furnace, heated from room temperature to 850℃ at a rate of 5℃ / min, and calcined for 60 min to obtain Mg-Li-Sc-Ti@MBene alloy;

[0070] S3, preparation of suture gun core

[0071] The Mg-Li-Sc-Ti@MBene alloy was cut into a 310 mm cylinder, annealed at 300℃ for 3 h, then placed in an extrusion cylinder for extrusion (extrusion ratio 16, extrusion rate 5 m / min, extrusion temperature 400℃), taken out after water cooling at 30℃ for 40 min, and placed in a numerical control machine tool to process the shape of the suture gun core, and the surface impurities were cleaned with anhydrous ethanol for 5 min to obtain the suture gun core.

[0072] Comparative example

[0073] In order to explore the influence of different parameters and different alloy elements in the preparation process of the present application on the performance of the product of the present application, the following comparative experiments were carried out, and different alloys were prepared as suture gun cores in the following comparative examples, as follows:

[0074] Comparative example 1

[0075] This comparative example prepared a Mg-4Y-2Nd-Zr (Y: 4 wt.%, Nd: 2 wt.%, Zr: 1 wt.%, and the balance was Mg) alloy as a suture gun core, and the specific preparation method was as follows:

[0076] The materials were prepared according to the alloy ratio, argon was used as the protective gas, the temperature was increased from room temperature to 750°C at a heating rate of 2°C / min, kept warm for 3 hours, and then cooled from 750°C to 600°C at a cooling rate of 5°C / min. The alloy was extruded at 400 MPa, and then demolded after cooling at room temperature for 20 minutes to obtain an alloy ingot, which was extruded into a rod with a diameter of 3 mm and a length of 300 mm. A fine tapered suture gun core with a diameter of 3 mm and a length of 300 mm was processed using a CNC machine tool. The surface impurities were ultrasonically cleaned with anhydrous ethanol, and the sample was vacuum-packed in a sample bag after drying for 30 minutes. Finally, it was sterilized by ultraviolet irradiation for 1 hour to obtain a suture gun core.

[0077] Comparative Example 2

[0078] In this comparative example, a 022Cr17Ni12Mo2 alloy (according to the composition mass percentage: Cr: 18wt.%, Ni: 10wt.%, Mo: 3wt.%, and the balance is Fe) is prepared as a suture gun core, and the preparation process is the same as that of comparative example 1.

[0079] Comparative Example 3

[0080] In this comparative example, a Ti-6Al-4V alloy (according to the composition mass percentage: Al: 6wt.%, V: 4wt.%, and the balance is Ti) is prepared as a suture gun core, and the preparation process is the same as that of comparative example 1.

[0081] Comparative Example 4

[0082] In this comparative example, a Mg-4Li-10Sc-2Ti@1.5MBene alloy (composition weight percentages are: Li: 4wt.%, Sc: 10wt.%, Ti: 2wt.%, MBene: 1.5wt.%) is prepared as a suture gun core. The core has a thin cone shape, a diameter of 3mm, and a length of 275mm. The preparation steps are the same as those in Example 1.

[0083] Comparative Example 5

[0084] In this comparative example, a Mg-20Li-2Sc-0.5Ti@0.5MBene alloy (composition weight percentages are: Li: 20wt.%, Sc: 2wt.%, Ti: 0.5wt.%, MBene: 0.5wt.%) is prepared as a suture gun core. The core is in the form of a sheet with a diameter of 4mm and a length of 275mm. The preparation steps are the same as those in Example 1.

[0085] Comparative Example 6

[0086] A Mg-Li-Sc-Ti@MBene alloy was prepared as a suture gun core in this comparative example, wherein the hard needle part contains Li 6wt.%, Sc 15wt.%, Ti 4wt.%, MBene 3wt.%, and the balance is Mg; the soft needle part contains Li 10wt.%, Sc 5wt.%, Ti 2wt.%, MBene 1.5wt.%, and the balance is Mg; the transition zone is located between the hard needle part and the soft needle part, and each element composition is gradually distributed. The preparation steps are the same as those of Example 1.

[0087] Comparative Example 7

[0088] A suture gun core was prepared in this comparative example, and the preparation process was similar to that of Example 1, except that in step S2, no Li powder was added, and the remaining steps and parameters were the same as those of Example 1.

[0089] Comparative Example 8

[0090] A suture gun core was prepared in this comparative example, and the preparation process was similar to that of Example 1, except that in step S2, no Sc powder was added, and the remaining steps and parameters were the same as those of Example 1.

[0091] Comparative Example 9

[0092] A suture gun core was prepared in this comparative example, and the preparation process was similar to that of Example 1, except that in step S2, no Ti powder was added, and the remaining steps and parameters were the same as those of Example 1.

[0093] Comparative Example 10

[0094] A suture gun core was prepared in this comparative example, and the preparation process was similar to that of Example 1, except that in step S2, no MBene was added, and the remaining steps and parameters were the same as those of Example 1.

[0095] Comparative Example 11

[0096] A suture gun core was prepared in this comparative example, and the preparation process was similar to that of Example 1, except that in step S2, the pressure during cold isostatic pressing was 500 MPa, and the treatment time was 20 min.

[0097] Comparative Example 12

[0098] A suture gun core was prepared in this comparative example, and the preparation process was similar to that of Example 1, except that in step S2, the temperature during calcination was 600°C, the time was 60 min, and the heating rate was 10°C / min.

[0099] Performance Test

[0100] The suture gun core prepared in Example 1 of the present application and Comparative Examples 1-12 was subjected to relevant performance tests, and the details are as follows:

[0101] As shown in Figure 1 The microstructure diagram of the transition zone of the magnesium alloy suture gun core prepared in Example 1 of the present application is shown in Figure 1, from which it can be seen that the grains gradually transition from coarse grains to fine grains, and the transition zone is made of functionally graded materials with varying grain sizes.

[0102] As shown in Figure 2 The scanning electron microscope diagram of the MBene nanosheet prepared in step S1 of Example 1 of the present application is shown in Figure 2, from which it can be seen that the MBene nanosheet has a single-layer structure, can absorb energy and inhibit crack propagation, and can improve the mechanical properties of the material by increasing the material interface bonding force.

[0103] As shown in Figure 3 The actual diagram of the suture gun core prepared in Example 1 of the present application is shown in Figure 3, from which it can be seen that the core includes a hard needle part, a soft needle part and a transition zone, and the total length is 275 mm, wherein the diameter of the hard needle part is 4 mm, the length is 200 mm, and the shape is a thin rod; the width of the soft needle part is 2 mm, the length is 55 mm, the thickness is 0.5 mm, and the shape is a sheet; the diameter of the transition zone is 3 mm, the length is 20 mm, and the shape is a ladder.

[0104] As shown in Figure 4 The longitudinal section diagram of the suture gun core prepared in Example 1 of the present application is shown in Figure 4, from which it can be seen that the transition zone of the core is in the shape of a trapezoid, which connects the hard needle part and the soft needle part, the material grains of the hard needle part are relatively coarse, which can ensure that it has higher hardness, the material grains of the soft needle part are relatively fine, which can ensure that it has higher toughness, and the transition zone connects the hard needle part and the soft needle part, so that the two parts are uniformly transitioned.

[0105] As shown in Figure 5 The X-ray fluorescence spectrum of the suture gun core prepared in Example 1 of the present application at four points is shown in Figure 5, wherein point A is located in the hard needle part, points B and C are located in the transition zone, and point D is located in the soft needle part, from which it can be seen that the composition of points B and C in the transition zone is between that of point A in the hard needle part and point D in the soft needle part, indicating that the element content of each part of the suture gun core is different, and the element content of the transition zone is between that of the hard needle part and the soft needle part.

[0106] The soft needle part of the suture gun core prepared in Example 1 of the present application was placed in Hank's solution (simulating human body fluid), and the corrosion morphology of the soft needle part in Hank's solution within 1-6 days was observed, as shown in Figure 6 From left to right, the corrosion effects of the first day to the sixth day are shown in the figure, from which it can be seen that the magnesium alloy produces corrosion products on the surface in Hank's solution, the mass decreases, and the corrosion rate of the soft needle part of the core is 0.085 mg / cm2 / Day, indicating that the core material can ensure the smooth progress of the shoulder sleeve suture operation and can ensure that the soft needle part of the core breaks and degrades in the human body.

[0107] The hardness, tensile strength, corrosion rate and cell survival rate of the suture gun cores prepared in Examples 1-3 and Comparative Examples 1-12 were tested, and the specific test results are shown in the following table:

[0108]

[0109] As can be seen from the above table, although the corrosion rate of the core prepared in Comparative Example 1 is relatively fast, the hardness, tensile strength and cell survival rate of the core prepared in Comparative Example 1 are lower than those of Examples 1-3, which indicates that the magnesium alloy composite material of the present application is superior to the traditional medical magnesium alloy in terms of mechanical properties and is less likely to break during use; although the tensile strength of the core prepared in Comparative Example 2 is superior to that of Examples 1-3, its hardness, corrosion rate and cell survival rate are lower than those of Examples 1-3, which indicates that the traditional medical stainless steel material is prone to breakage during use and is not easy to degrade in the human body, and also causes damage to human cells; although the hardness and tensile strength of Comparative Example 3 are superior to those of Examples 1-3, it still has the risk of breaking in the bone suture operation environment, and due to its low corrosion rate and cell survival rate, it indicates that the traditional medical titanium alloy material is not easy to degrade in the human body and will cause damage to human cells, which will increase the risk of secondary surgery to remove the needle core; Comparative Example 4 uses the composition of the hard needle part (Mg-4Li-10Sc-2Ti@1.5MBene) to prepare an overall homogeneous core, which has high tensile strength, but lacks the flexibility of the soft needle part, which cannot adapt to the bending operation of tendon suture, and is prone to overall breakage during surgery; Comparative Example 5 uses the composition of the soft needle part (Mg-20Li-2Sc-0.5Ti@0.5MBene) to prepare an overall sheet-shaped core, although its elongation is improved, but the strength is low, which leads to the inability of the core to perform surgical operation; Comparative Example 6 adjusts the element content, and due to the content of Sc, Ti and MBene exceeding the range of the present application, the hardness and tensile strength of the core are decreased; Comparative Example 7 does not add Li element, and the hardness and tensile strength of the hard needle part are reduced by 34.6% and 33.1% compared with Example 1, which proves that the key role of Li to the toughness of α-Mg solid solution is missing, and the brittleness of the material is significantly increased; Comparative Example 8 does not add Sc element, and the corrosion rate of the soft needle part is increased to 0.093 mg / cm 2The gun core hardness and tensile strength of the comparative example 9 are reduced, which confirms that the fine grain strengthening effect of Ti is invalid; the tensile strength of the hard needle part of the comparative example 10 is reduced by 13.4%, and the crack propagation rate of the soft needle part is accelerated in the fatigue cycle test, which proves that the absence of the effect of MBene on the interfacial bonding force and crack inhibition will lead to the decrease of the tensile strength of the alloy; the cold isostatic pressing pressure of the comparative example 11 is increased to 500 MPa, microcracks are generated in the material, and the gun core hardness and tensile strength are reduced, which shows that high pressure destroys the integrity of particle combination; the calcination temperature of the comparative example 12 is reduced to 600 DEG C, the alloy is not sufficiently densified, the porosity is greater than 15%, the strength of the hard needle part is reduced, and the corrosion rate is increased by 29.4%, which confirms that low temperature calcination leads to structural defects. Comparative examples 1-5 prove that gradient composition design is a necessary condition for considering high strength of the hard needle part and high toughness of the soft needle part; comparative examples 6-10 prove that the four elements of Li, Sc, Ti and MBene are indispensable, and the absence of any element will lead to significant deterioration of the mechanical properties or corrosion resistance; comparative examples 11-12 prove that strict process parameters are the key to ensure material densification and performance stability.

[0110] In summary, the gun core of the magnesium alloy for shoulder joint repair surgery suture gun prepared by the application can realize smooth transition of material performance, meet the differentiated needs of different regions for mechanical properties. The high strength and high hardness of the hard needle part enable it to be firmly fixed inside the suture gun without falling off; the good biocompatibility of the soft needle part enables it to be absorbed by the human body after breaking in the human body, so that secondary surgery is not needed to take it out, avoiding the problem that the traditional gun core cannot be degraded after breaking in the human body and will remain in the body for a long time. The gradient material design between the hard needle part and the soft needle part can effectively solve the problem of stress concentration and high risk of fracture at the interface of the existing shoulder joint suture gun gun core.

[0111] Finally, it should be noted that: the above only describes the preferred embodiments of the application and is not intended to limit the application, although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent replacement of some technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the scope of protection of the claims of the application.

Claims

1. A magnesium alloy gun core for a rotator cuff repair surgery suture gun, characterized in that: The gun core includes a hard needle portion, a transition zone, and a soft needle portion; the hard needle portion has a diameter of 4 to 6 mm, a length of 200 to 220 mm, and a thin rod shape; the transition zone has a diameter of 2 to 6 mm, a length of 20 to 30 mm, and a terraced shape; the soft needle portion has a width of 2 to 4 mm, a length of 50 to 60 mm, a thickness of 0.5 mm, and a sheet shape; The gun core material is Mg-Li-Sc-Ti@MBene alloy; in terms of weight percentage, the hard needle part contains Li 4wt.%, Sc 10wt.%, Ti 2wt.%, MBene 1.5wt.%, and the balance is Mg; the soft needle part contains Li 20wt.%, Sc 2wt.%, Ti0.5wt.%, MBene 0.5wt.%, and the balance is Mg; the Li content in the transition zone gradually increases from 4wt.% to 20wt.%, the Sc content gradually decreases from 10wt.% to 2wt.%, the Ti content gradually decreases from 2wt.% to 0.5wt.%, and the MBene content gradually decreases from 1.5wt.% to 0.5wt.%, and the balance is Mg.

2. The method for preparing a magnesium alloy gun core for a rotator cuff repair surgery suture gun according to claim 1, characterized in that: Follow the steps below in order: S1. Preparation of MBene Weigh (Mo 2 / 3 Y 1 / 3 )2AlB2 and add 40wt.% HF solution, etch at 35-60°C for 16h, wash with deionized water 3-5 times, add 10-20mL 2mol / L TMAOH solution, stir at 3-5°C for 1-5h, wash with anhydrous ethanol 3-5 times, centrifuge at 3500-10500rpm for 15-30min, and freeze-dry to obtain MBene; S2. Preparation of Mg-Li-Sc-Ti@MBene alloy Under an argon atmosphere, Mg powder, Li powder, Sc powder, Ti powder, and MBene powder were evenly spread in a trough crucible according to the atomic ratio of each region. 1 to 10 g of binder was added. After cold isostatic pressing at room temperature, the mixture was calcined in a muffle furnace to obtain a Mg-Li-Sc-Ti@MBene alloy. S3. Prepare the suture gun core The Mg-Li-Sc-Ti@MBene alloy was cut into cylinders of 275 to 310 mm, annealed at 250 to 300 ° C for 0.5 to 3 h, and then placed in an extrusion barrel for extrusion. The alloy was water-cooled at 20 to 30 ° C for 20 to 40 minutes, taken out, and placed in a CNC machine tool to process the shape of a sewing gun core. The surface impurities were then cleaned using anhydrous ethanol ultrasonically for 3 to 5 minutes to obtain a sewing gun core.

3. The method for preparing a magnesium alloy gun core for a rotator cuff repair surgery suture gun according to claim 2, characterized in that: In step S1, the (Mo 2 / 3 Y 1 / 3 )2AlB2 and HF solution with a mass fraction of 40wt.% have a mass volume ratio of (1-2): (10-20) g / mL.

4. The method for preparing a magnesium alloy gun core for a rotator cuff repair surgery suture gun according to claim 2, characterized in that: In step S1, the freeze-drying temperature is -10 to 5°C and the time is 12 to 36 hours.

5. The method for preparing a magnesium alloy gun core for a rotator cuff repair surgery suture gun according to claim 2, characterized in that: In step S2, the binder is one or more of phenolic resin, magnesium aluminum silicate, polyvinyl chloride, 107 glue, white latex, and sodium silicate.

6. The method for preparing a magnesium alloy gun core for a rotator cuff repair surgery suture gun according to claim 2, characterized in that: In step S2, the pressure during the cold isostatic pressing treatment is 200-350 MPa, and the treatment time is 40-60 minutes.

7. The method for preparing a magnesium alloy gun core for a rotator cuff repair surgery suture gun according to claim 2, characterized in that: In step S2, the calcination temperature is 700-850°C, the time is 40-60 minutes, and the heating rate is 2-5°C / min.

8. The method for preparing a magnesium alloy gun core for a rotator cuff repair surgery suture gun according to claim 2, characterized in that: In step S3, the extrusion ratio is 10-16, the extrusion rate is 1-5 m / min, and the temperature is 300-400°C.

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