A magnesium alloy gun core for a rotator cuff repair surgery suturing gun and a preparation method thereof

Abstract

The application discloses a magnesium alloy gun core for a rotator cuff repair surgery suture gun 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. In terms of weight percentage, the content of each part element is as follows: the hard needle part contains 4wt.% of Li, 10wt.% of Sc, 2wt.% of Ti and 1.5wt.% of MBene, and the balance is Mg; the soft needle part contains 20wt.% of Li, 2wt.% of Sc, 0.5wt.% of Ti and 0.5wt.% of MBene, and the balance is Mg; the transition zone is located between the hard needle part and the soft needle part, and each element component is gradually distributed. The gun core is prepared by an alloy melting and casting method and a gradient extrusion method. The gun core has good mechanical properties, biocompatibility and degradability, improves the efficiency and safety of rotator cuff repair surgery, and reduces the probability of secondary surgery.

Description

Technical Field

[0001] This invention belongs to the field of medical device material preparation, and relates to a magnesium alloy gun core for a rotator cuff repair surgical suture gun and its preparation method. Background Technology

[0002] Rotator cuff repair is a surgical procedure that restores the integrity of the rotator cuff by suturing torn tendons. Currently, rotator cuff repair surgery typically uses instruments such as suture guns and suture anchors to fix the damaged rotator cuff tissue. The suture instruments and materials used in rotator cuff repair are crucial to the surgical outcome. Suture instruments are typically used to precisely place sutures on the torn tendons and bones. The suture gun used in rotator cuff repair surgery consists of two parts: the gun body and the core. Existing suture gun cores are mostly made of materials such as stainless steel or titanium alloy, but their structure is thin and brittle. Given the complex and variable nature of surgical situations, if the core accidentally breaks off inside the body, it is difficult for medical personnel to remove. Furthermore, materials such as stainless steel are not easily degraded in the human body, which can affect the rotator cuff and surrounding tissues.

[0003] Given the high fracture risk and poor biocompatibility of existing suture gun core materials, the development of novel materials that combine high strength with good biodegradability is urgently needed. Magnesium-based composites, with their biodegradability and lightweight advantages, have become highly promising alternative materials. However, increasing the hardness of magnesium composites usually requires increasing grain boundary strengthening or precipitates, which often leads to a decrease in toughness. Increased hardness is typically accompanied by grain refinement or an increase in second-phase particles; these changes hinder dislocation movement, thereby increasing strength, but also limit the material's plastic deformation capacity and reduce toughness. Therefore, when optimizing the properties of magnesium composites, a balance needs to be found between hardness and toughness.

[0004] Chinese invention patent application number 201920284701.0 discloses an instrument for rotator cuff repair surgery, which integrates tissue grasping and suture passing functions. Its innovative structural design simplifies operation, reduces the number of instruments, and improves surgical efficiency. However, this patent lacks description of the instrument's materials. Most commercially available rotator cuff repair surgical instruments are made of stainless steel. Due to its unique structure, the soft needle core is highly susceptible to breakage during surgery, thus posing a risk of requiring a second surgery to remove the soft needle core.

[0005] The paper "Metals 2024, 14, 288" discloses a biodegradable suture anchor made of a Mg-2.8Nd-0.2Zn-0.4Zr (wt.%) alloy for ligament-bone fixation in rotator cuff surgery, and investigates its mechanical properties and in vitro corrosion behavior. Although magnesium alloys have good degradability and biocompatibility, their corrosion resistance remains limited. After implantation, they release hydrogen, affecting normal tissue function and the healing process. Furthermore, their mechanical properties gradually decrease with degradation, weakening the rotator cuff fixation effect. Therefore, magnesium alloys still have limitations in the application of rotator cuff tendon fixation.

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

[0007] First, the shoulder sleeve sewing core is prone to breakage during use;

[0008] Second, traditional medical magnesium alloy materials are not suitable for rotator cuff suture gun cores;

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

[0010] Based on this, the present invention 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 due to core breakage in the human body. Summary of the Invention

[0011] To address the aforementioned technical problems, this invention aims to provide a magnesium alloy suture core for rotator cuff repair surgery and its preparation method. The core comprises a hard needle section, a transition zone, and a soft needle section. The core material is a Mg-Li-Sc-Ti@MBene alloy, with the following elemental contents by weight percentage: the hard needle section contains 4wt.% Li, 10wt.% Sc, 2wt.% Ti, 1.5wt.% MBene, and the balance being Mg; the soft needle section contains 20wt.% Li, 2wt.% Sc, 0.5wt.% Ti, 0.5wt.% MBene, and the balance being Mg. The transition zone is located between the hard and soft needle sections, with a gradual distribution of elemental composition. This core is prepared using alloy casting and gradient extrusion methods, exhibiting excellent mechanical properties, biocompatibility, and biodegradability, thus improving the efficiency and safety of rotator cuff repair surgery while reducing the probability of needing a second surgery.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0013] A magnesium alloy core for a rotator cuff repair surgical suture gun, the core comprising a hard needle section, a transition zone, and a soft needle section; the hard needle section has a diameter of 4-6 mm, a length of 200-220 mm, and is shaped like a thin rod; the transition zone has a diameter of 2-6 mm, a length of 20-30 mm, and is shaped like a trapezoid; the soft needle section has a width of 2-4 mm, a length of 50-60 mm, a thickness of 0.5 mm, and is shaped like a sheet.

[0014] The core material is a Mg-Li-Sc-Ti@MBene alloy; by weight percentage, the hard needle portion contains 4wt.% Li, 10wt.% Sc, 2wt.% Ti, 1.5wt.% MBene, with the balance being Mg; the soft needle portion contains 20wt.% Li, 2wt.% Sc, 0.5wt.% Ti, 0.5wt.% MBene, with the balance being Mg; the transition zone is the area where the hard needle portion transitions to the soft needle portion. As the transition zone moves from the hard needle portion to the soft needle portion, 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.%, and the MBene content gradually decreases from 1.5wt.% to 0.5wt.%, with the balance being Mg.

[0015] The rotator cuff suture gun of this invention has a groove at the top of the hard needle part of the gun core. The groove is designed as a tenon and mortise structure to fix the gun core inside the gun body. The transition area is shaped like a trapezoid, connecting the hard needle part and the soft needle part. The soft needle part is shaped like a sheet, with a needle tip at the tail. The bottom of the needle tip is pointed, which can pierce human skin, rotator cuff tendons and bone tissue. There are two grooves above the tip, which are used for wrapping surgical sutures.

[0016] In this invention, the addition of Li reduces the density and increases the toughness of the magnesium composite material. The low Li content forms an α-Mg solid solution in the Mg matrix, providing basic toughness. The addition of Sc enhances the hardness of the magnesium composite material through second-phase strengthening and solid solution strengthening. Sc forms a Mg-Sc intermetallic compound with Mg, and improves the hardness and strength of the hard needles through solid solution strengthening and precipitation strengthening. Moreover, the scandium oxide formed by Sc during corrosion can form a passivation layer on the surface of the magnesium composite material, thereby improving the corrosion resistance of the material. The addition of Ti refines the grains, forming a fine-grained structure, and reacts with Mg to form a Mg-Ti precipitate, further strengthening the matrix. Simultaneously, the grain refinement effect of Ti provides a more uniform and finer distribution site for the Sc precipitate. The passivation layer of Sc protects the magnesium matrix optimized by the combined action of Li and Ti, and the addition of Li and Ti does not impair the ability of Sc to form an effective passivation layer. This effect ensures that the material achieves excellent mechanical properties while also possessing good corrosion resistance. The introduction of MBene enhances the interfacial bonding of the material, inhibits localized corrosion during degradation, and improves mechanical properties and biosafety. MBene, as a two-dimensional nanosheet, is uniformly dispersed in the magnesium composite matrix. Through second-phase reinforcement and grain boundary pinning effects, it effectively hinders dislocation movement. Furthermore, MBene forms a coherent interface with the Mg-Sc phase, reducing the tendency for galvanic corrosion at grain boundaries. The introduction of MBene nanosheets enhances the interfacial bonding of the material, enabling the alloy to achieve a hardness of over 185 HV, meeting the high strength requirements for bone puncture. In addition, the layered structure of MBene can absorb energy and inhibit crack propagation, improving the flexibility of the soft needle.

[0017] In this invention, the content of each element is key to achieving good mechanical properties and biocompatibility of the magnesium alloy gun core. The hard needle portion of the gun core contains 4 wt.% Li, 10 wt.% Sc, 2 wt.% Ti, and 1.5 wt.% MBene, with the balance being Mg. This ensures that the hard needle portion meets the hardness requirements for rotator cuff surgery. Increasing the content of each element and decreasing the Mg content will increase the brittleness of the hard needle portion due to the reduction of the solid solution strengthening phase of Mg, making it more prone to fracture. Conversely, decreasing the content of each element and increasing the Mg content will lead to the formation of a pure magnesium layer at the grain boundaries, making dislocation movement more likely and reducing the hardness of the hard needle portion, thus causing the gun core to fracture. The soft needle portion of the gun core contains 20 wt.% Li, 2 wt.% Sc, 0.5 wt.% Ti, and 1.5 wt.% MBene. The content is 0.5 wt.%, with the balance being Mg. This content ensures that the soft needle of the needle core meets the hardness requirements for bone puncture, while also possessing high toughness to ensure that the needle core can be operated in the bone suture. If the content of each element is increased and the Mg content is decreased, the soft needle will become less tough and more likely to break in the human body because the second phase between the metals is more likely to form crack sources. If the content of each element is decreased and the Mg content is increased, a pure magnesium layer will form at the grain boundaries, making dislocation movement more likely and reducing the hardness of the soft needle, making bone puncture impossible.

[0018] This invention also provides a method for preparing a magnesium alloy gun core for a rotator cuff repair surgical suture gun, which is carried out in the following order:

[0019] S1. Preparation of MBene

[0020] Weigh (Mo 2 / 3 Y 1 / 3 )2AlB2 was added to HF solution with a mass fraction of 40 wt.%, etched at 35-60℃ for 16 h, washed 3-5 times with deionized water, then 10-20 mL of 2 mol / L TMAOH solution was added, stirred at 3-5℃ for 1-5 h, then washed 3-5 times with anhydrous ethanol, centrifuged at 3500-10500 rpm for 15-30 min, and freeze-dried 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 are evenly spread in a trough-shaped crucible according to the atomic ratio of each region. 1-10g of binder is added, and after cold isostatic pressing at room temperature, it is placed in a muffle furnace for calcination to obtain Mg-Li-Sc-Ti@MBene alloy.

[0023] S3. Preparing the core of the sewing gun

[0024] The Mg-Li-Sc-Ti@MBene alloy was cut into cylinders of 275–310 mm and annealed at 250–300 °C for 0.5–3 h. The cylinders were then extruded and water-cooled at 20–30 °C for 20–40 min. The alloys were then removed and placed in a CNC machine tool to machine the shape of the sewing gun core. The surface impurities were cleaned by ultrasonic cleaning with anhydrous ethanol for 3–5 min to obtain the sewing gun core.

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

[0026] As another limitation of the preparation method of the present invention, in step S1, the temperature during freeze drying is -10 to 5°C and the time is 12 to 36 hours.

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

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

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

[0030] In this invention, the calcination of the alloy affects its mechanical properties. When the calcination temperature is 700–850℃, the powder particles rearrange, reducing the porosity between particles and thus increasing the material's density. If the temperature is above 850℃, premature tight bonding between particles will affect the formation of solid solution, leading to a deterioration in the material's mechanical properties. If the temperature is below 700℃, the contact and diffusion rates between particles will be greatly reduced, resulting in a porous and loose material with poor mechanical properties, making it highly susceptible to corrosion and affecting the surgical procedure. Holding the temperature for 40–60 minutes helps to gradually increase the contact area between particles and reduce porosity. If the holding time is greater than 60 minutes, the bonding force between particles will be too strong, causing deformation between particles and affecting the performance of the magnesium alloy material. If the holding time is less than 40 minutes, the bonding force between particles will be too weak, resulting in insufficient tight bonding between particles and increasing the material's porosity. Setting the heating rate to 2-5℃ / min ensures a gradual and uniform temperature increase, avoiding excessive thermal expansion stress. If the heating rate is greater than 5℃ / min, it will lead to excessive internal thermal stress in the material, causing cracking or deformation. If the heating rate is less than 2℃ / min, the heating time will be too long, increasing production time and energy consumption.

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

[0032] The above-mentioned technical solution of the present invention is a whole in which each step is closely related and mutually influential, and together they determine the morphological characteristics and performance of the product.

[0033] The above technical solution has the following advantages or beneficial effects:

[0034] 1. The magnesium alloy suture gun core prepared by this invention has good biocompatibility, will not cause rejection reaction with the human body during surgery, and reduces the risk of surgical failure due to core breakage in the human body.

[0035] 2. This invention uses a gradient design to give the hard needle part high strength and high rigidity, and the soft needle part high flexibility and fatigue resistance. The transition zone achieves a smooth transition of mechanical properties, thereby improving the overall performance of the gun core and the safety of the operation.

[0036] 3. The magnesium alloy suture gun core prepared by this invention has a tensile strength ≥340MPa and a microhardness ≥185HV, which meets the requirements for bone puncture; the soft needle part has high elongation and fatigue resistance, which can adapt to the repeated bending of tendon suture; the transition zone can effectively suppress the risk of fracture caused by stress concentration at the interface; and the gradient performance is highly matched with the mechanical gradient of bone-tendon-skin through phase transformation, thereby improving the success rate of surgery.

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

[0038] This invention is applicable to the preparation of magnesium alloy stitching gun cores.

[0039] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0040] Figure 1 This is a microstructure image of the magnesium alloy gun core for the suture gun prepared in Example 1 of the present invention;

[0041] Figure 2 This is a scanning electron microscope image of the MBene nanosheets prepared in step S1 of Example 1 of the present invention;

[0042] Figure 3 This is a physical image of the magnesium alloy gun core for the stitching gun prepared in Example 1 of the present invention;

[0043] Figure 4 This is a simplified longitudinal section view of the magnesium alloy gun core for the stitching gun prepared in Example 1 of the present invention;

[0044] Figure 5 The compositional analysis diagram of the suture gun core prepared in Example 1 of the present invention at four points is shown, 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;

[0045] Figure 6 The images show the corrosion morphology of the suture gun core prepared in Example 1 of this invention after 1 to 6 days in Hank's solution (simulating human body fluid). Detailed Implementation

[0046] The following embodiments are merely some, not all, of the embodiments of the present invention. Therefore, the detailed descriptions of the embodiments provided below are not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0047] In this invention, unless otherwise specified, all equipment and raw materials are commercially available or commonly used in the industry. The methods described in the following embodiments are conventional methods in the art, unless otherwise specified.

[0048] Example 1

[0049] This embodiment prepares a magnesium alloy core for a rotator cuff repair surgical suture gun. The core includes a hard needle section, a transition zone, and a soft needle section. The hard needle section has a diameter of 4 mm, a length of 200 mm, and is shaped like a thin rod; the transition zone has a diameter of 2 mm, a length of 20 mm, and is shaped like a trapezoid; the soft needle section has a width of 2 mm, a length of 55 mm, a thickness of 0.5 mm, and is shaped like a sheet. The magnesium alloy gun core has the following composition: Hard needle section contains 4 wt.% Li, 10 wt.% Sc, 2 wt.% Ti, and 1.5 wt.% MBene, with the balance being Mg; Soft needle section contains 20 wt.% Li, 2 wt.% Sc, 0.5 wt.% Ti, and 0.5 wt.% MBene, with the balance being Mg. In the transition region, the Li content gradually increases from 4 wt.% to 20 wt.%, the Sc content gradually decreases from 10 wt.% to 2 wt.%, the Ti content gradually decreases from 2 wt.% to 0.5 wt.%, and the MBene content gradually decreases from 1.5 wt.% to 0.5 wt.%, with the balance being Mg. The gun core preparation process and steps are as follows:

[0050] S1. Preparation of MBene

[0051] Weigh 1g (Mo) 2 / 3 Y 1 / 3 )2AlB2 was added to 10 mL of HF solution with a mass fraction of 40 wt.%, etched at 35 °C for 16 h, washed 3 times with deionized water, then 10 mL of 2 mol / L TMAOH solution was added, stirred at 3 °C for 1 h, then washed 3 times with anhydrous ethanol, centrifuged at 3500 rpm for 30 min, and freeze-dried at -10 °C for 12 h 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 were uniformly spread in a trough-shaped crucible according to the atomic ratio of each region (hard needle section at the front of the crucible, transition zone in the middle, and soft needle section at the rear, with powder spreading controlled by AFS-M20X). 1g of phenolic resin was added, and the mixture was subjected to cold isostatic pressing at 200MPa for 40min at room temperature. Then, it was placed in a muffle furnace and heated from room temperature to 700℃ at a heating rate of 2℃ / min, and calcined for 40min to obtain the Mg-Li-Sc-Ti@MBene alloy.

[0054] S3. Preparing the core of the sewing gun

[0055] The Mg-Li-Sc-Ti@MBene alloy was cut into 275mm cylinders, annealed at 250℃ for 0.5h, and then extruded in an extrusion cylinder (extrusion ratio of 10, extrusion rate of 1m / min, extrusion temperature of 300℃). After water cooling at 20℃ for 20min, the alloy was removed and placed in a CNC machine tool to machine the shape of the sewing gun core. Then, the surface impurities were cleaned by ultrasonic cleaning with anhydrous ethanol for 3min to obtain the sewing gun core.

[0056] Example 2

[0057] This embodiment prepares a magnesium alloy core for a rotator cuff repair surgical suture gun. The core includes a hard needle section, a transition zone, and a soft needle section. The hard needle section has a diameter of 5 mm, a length of 210 mm, and is shaped like a thin rod; the transition zone has a diameter of 4 mm, a length of 25 mm, and is shaped like a trapezoid; the soft needle section has a width of 3 mm, a length of 50 mm, a thickness of 0.5 mm, and is shaped like a sheet. The hard needle portion contains 4 wt.% Li, 10 wt.% Sc, 2 wt.% Ti, and 1.5 wt.% MBene, with the balance being Mg; the soft needle portion contains 20 wt.% Li, 2 wt.% Sc, 0.5 wt.% Ti, and 0.5 wt.% MBene, with the balance being Mg. In the transition region, the Li content gradually increases from 4 wt.% to 20 wt.%, the Sc content gradually decreases from 10 wt.% to 2 wt.%, the Ti content gradually decreases from 2 wt.% to 0.5 wt.%, and the MBene content gradually decreases from 1.5 wt.% to 0.5 wt.%, with the balance being Mg. The preparation process and steps of the gun core are as follows:

[0058] S1. Preparation of MBene

[0059] Weigh 1.5g (Mo) 2 / 3 Y 1 / 3 )2AlB2 and 15 mL of HF solution with a mass fraction of 40 wt.% were added. The mixture was etched at 50 °C for 16 h. After washing with deionized water 4 times, 15 mL of 2 mol / L TMAOH solution was added. The mixture was stirred at 4 °C for 3 h. After washing with anhydrous ethanol 4 times, the mixture was centrifuged at 9500 rpm for 20 min and then freeze-dried at 0 °C for 24 h to obtain MBene.

[0060] S2. Preparation of Mg-Li-Sc-Ti@MBene alloy

[0061] Under an argon atmosphere, Mg powder, Li powder, Sc powder, Ti powder, and MBene powder were uniformly spread in a trough-shaped crucible according to the atomic ratio of each region (the front of the crucible was used to cast hard needles, the middle was used to cast transition zones, and the rear was used to cast soft needles, with powder spreading controlled by AFS-M20X). 5g of magnesium aluminum silicate was added, and the mixture was subjected to cold isostatic pressing at 300MPa for 50min at room temperature. Then, it was placed in a muffle furnace and heated from room temperature to 800℃ at a heating rate of 3℃ / min, and calcined for 50min to obtain the Mg-Li-Sc-Ti@MBene alloy.

[0062] S3. Preparing the core of the sewing gun

[0063] The Mg-Li-Sc-Ti@MBene alloy was cut into 285mm cylinders, annealed at 275℃ for 1 hour, and then extruded in an extrusion cylinder (extrusion ratio of 14, extrusion rate of 3m / min, extrusion temperature of 350℃). After water cooling at 25℃ for 30 minutes, the alloy was removed and placed in a CNC machine tool to machine the shape of the sewing gun core. The surface impurities were cleaned by ultrasonic cleaning with anhydrous ethanol for 4 minutes to obtain the sewing gun core.

[0064] Example 3

[0065] This embodiment prepares a magnesium alloy core for a rotator cuff repair surgical suture gun. The core includes a hard needle section, a transition zone, and a soft needle section. The hard needle section has a diameter of 6 mm, a length of 220 mm, and is shaped like a thin rod; the transition zone has a diameter of 6 mm, a length of 30 mm, and is shaped like a trapezoid; the soft needle section has a width of 4 mm, a length of 60 mm, a thickness of 0.5 mm, and is shaped like a sheet. The hard needle portion contains 4 wt.% Li, 10 wt.% Sc, 2 wt.% Ti, and 1.5 wt.% MBene, with the balance being Mg; the soft needle portion contains 20 wt.% Li, 2 wt.% Sc, 0.5 wt.% Ti, and 0.5 wt.% MBene, with the balance being Mg. In the transition region, the Li content gradually increases from 4 wt.% to 20 wt.%, the Sc content gradually decreases from 10 wt.% to 2 wt.%, the Ti content gradually decreases from 2 wt.% to 0.5 wt.%, and the MBene content gradually decreases from 1.5 wt.% to 0.5 wt.%, with the balance being Mg. The preparation process and steps of the gun core are as follows:

[0066] S1. Preparation of MBene

[0067] Weigh 2g (Mo) 2 / 3 Y 1 / 3)2AlB2 was added to 20 mL of HF solution with a mass fraction of 40 wt.%, etched at 60 °C for 16 h, washed 5 times with deionized water, then 20 mL of 2 mol / L TMAOH solution was added, stirred at 5 °C for 5 h, then washed 5 times with anhydrous ethanol, centrifuged at 10500 rpm for 15 min, and freeze-dried at 5 °C 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 spread in a trough-shaped crucible according to the atomic ratio of each region (the front of the crucible was used to cast hard needles, the middle was used to cast transition zones, and the rear was used to cast soft needles, with powder spreading controlled by AFS-M20X). 10g of polyvinyl chloride was added, and the mixture was subjected to cold isostatic pressing at 350MPa for 60min at room temperature. Then, it was placed in a muffle furnace and heated from room temperature to 850℃ at a heating rate of 5℃ / min, and calcined for 60min to obtain the Mg-Li-Sc-Ti@MBene alloy.

[0070] S3. Preparing the core of the sewing gun

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

[0072] Comparative Example

[0073] To investigate the effects of different parameters and alloying elements on the performance of the product during the preparation process of this invention, the following comparative experiments were conducted. Different alloys were prepared as suture gun cores in the following comparative examples:

[0074] Comparative Example 1

[0075] This comparative example prepares a Mg-4Y-2Nd-Zr alloy (with the following composition by mass percentage: Y: 4wt.%, Nd: 2wt.%, Zr: 1wt.%, balance Mg) as a core for a stitching gun. The specific preparation method is as follows:

[0076] The alloy was prepared according to the alloy ratio, and 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 and held for 3 hours. Then, the temperature was decreased from 750°C to 600°C at a cooling rate of 5°C / min. The alloy was extruded at 400 MPa and then cooled at room temperature for 20 minutes before demolding to obtain an alloy ingot. This ingot was then extruded into a bar with a diameter of 3 mm and a length of 300 mm. A fine conical suture gun core with a diameter of 3 mm and a length of 300 mm was machined using a CNC machine tool. The surface impurities were ultrasonically cleaned with anhydrous ethanol, dried for 30 minutes, and then vacuum-packed in a sample bag. Finally, the core was sterilized by ultraviolet irradiation for 1 hour to obtain the suture gun core.

[0077] Comparative Example 2

[0078] In this comparative example, a 022Cr17Ni12Mo2 alloy (with the following composition by mass percentage: Cr: 18wt.%, Ni: 10wt.%, Mo: 3wt.%, and the balance being Fe) was prepared as the core of a stitching gun. The preparation process was the same as that of Comparative Example 1.

[0079] Comparative Example 3

[0080] In this comparative example, a Ti-6Al-4V alloy (with the following composition by mass percentage: Al: 6wt.%, V: 4wt.%, and the balance being Ti) was prepared as the core of a stitching gun. The preparation process was 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 (with the following composition by mass percentage: Li: 4wt.%, Sc: 10wt.%, Ti: 2wt.%, MBene: 1.5wt.%) was prepared as the core of a stitching gun. The core was thinly conical in shape, with a diameter of 3 mm and a length of 275 mm. The preparation steps were the same as in Example 1.

[0083] Comparative Example 5

[0084] In this comparative example, a Mg-20Li-2Sc-0.5Ti@0.5MBene alloy (with the following composition by mass percentage: Li: 20wt.%, Sc: 2wt.%, Ti: 0.5wt.%, MBene: 0.5wt.%) was prepared as the core of a stitching gun. The core was in sheet shape with a diameter of 4 mm and a length of 275 mm. The preparation steps were the same as in Example 1.

[0085] Comparative Example 6

[0086] This comparative example prepares a Mg-Li-Sc-Ti@MBene alloy as a suture gun core, wherein: the hard needle portion contains 6 wt.% Li, 15 wt.% Sc, 4 wt.% Ti, and 3 wt.% MBene, with the balance being Mg; the soft needle portion contains 10 wt.% Li, 5 wt.% Sc, 2 wt.% Ti, and 1.5 wt.% MBene, with the balance being Mg; the transition zone is located between the hard and soft needle portions, with the elemental composition showing a gradual distribution. The preparation steps are the same as in Example 1.

[0087] Comparative Example 7

[0088] This comparative example prepares a suture gun core. The preparation process is similar to that of Example 1, except that Li powder is not added in step S2. The remaining steps and parameters are the same as those in Example 1.

[0089] Comparative Example 8

[0090] This comparative example prepares a suture gun core. The preparation process is similar to that of Example 1, except that Sc powder is not added in step S2. The remaining steps and parameters are the same as those in Example 1.

[0091] Comparative Example 9

[0092] This comparative example prepares a suture gun core. The preparation process is similar to that of Example 1, except that Ti powder is not added in step S2. The remaining steps and parameters are the same as those in Example 1.

[0093] Comparative Example 10

[0094] This comparative example prepares a suture gun core. The preparation process is similar to that of Example 1, except that MBene is not added in step S2. The remaining steps and parameters are the same as those in Example 1.

[0095] Comparative Example 11

[0096] This comparative example prepares a suture gun core. The preparation process is similar to that of Example 1, except that in step S2, the pressure during cold isostatic pressing is 500 MPa and the processing time is 20 min.

[0097] Comparative Example 12

[0098] This comparative example prepares a suture gun core. The preparation process is similar to that of Example 1, except that in step S2, the calcination temperature is 600℃, the time is 60min, and the heating rate is 10℃ / min.

[0099] Performance testing

[0100] The suture gun cores prepared in Examples 1-3 and Comparative Examples 1-12 of this invention were subjected to relevant performance tests, as follows:

[0101] like Figure 1 The image shows the microstructure of the transition zone of the magnesium alloy gun core for the suture gun prepared in Example 1 of this invention. As can be seen from the image, the grains gradually transition from coarse to fine grains. The transition zone is made of a functionally graded material with varying grain sizes.

[0102] like Figure 2 The image shows a scanning electron microscope (SEM) image of the MBene nanosheets prepared in step S1 of Example 1 of this invention. As can be seen from the image, the MBene nanosheets have a monolayer structure, which can absorb energy and inhibit crack propagation, and improve the mechanical properties of the material by increasing the interfacial bonding force.

[0103] like Figure 3 The figure shows a physical image of the magnesium alloy core of the suture gun prepared in Example 1 of the present invention. As can be seen from the figure, the core includes a hard needle part, a soft needle part and a transition zone, with a total length of 275 mm. The hard needle part has a diameter of 4 mm, a length of 200 mm and a shape of thin rod; the soft needle part has a width of 2 mm, a length of 55 mm and a thickness of 0.5 mm and a shape of sheet; the transition zone has a diameter of 3 mm, a length of 20 mm and a shape of trapezoidal.

[0104] like Figure 4 The figure shows a simplified longitudinal section of the magnesium alloy core of the suture gun prepared in Example 1 of the present invention. As can be seen from the figure, the transition zone of the core is trapezoidal, which connects the hard needle part and the soft needle part. The hard needle part has coarser grains, which can ensure that it has higher hardness, while the soft needle part has finer grains, which can ensure that it has higher toughness. The transition zone connects the hard needle part and the soft needle part, so that the two parts transition evenly.

[0105] like Figure 5 The figure shows the X-ray fluorescence spectra of the suture gun core prepared in Example 1 of this invention at four points, where point A is located in the hard needle part, points B and C are located in the transition region, and point D is located in the soft needle part. As can be seen from the figure, the composition of points B and C in the transition region 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 region 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 was placed in Hank's solution (simulating human body fluid), and its corrosion morphology in Hank's solution was observed over 1 to 6 days. Figure 6 As shown in the figure, the corrosion effects from left to right are the first to sixth days. It can be seen from the figure that the magnesium alloy produces corrosion products on its surface in Hank's solution, resulting in a decrease in mass. The corrosion rate of the soft needle in the gun core is 0.085 mg / cm³.2 / Day indicates that the core material can ensure the smooth progress of rotator cuff suture surgery and that the soft needle part of the core can be degraded after breaking in the human body.

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

[0108]

[0109] As can be seen from the table above, compared with Examples 1-3, although the corrosion rate of the gun core prepared in Comparative Example 1 is relatively fast, its hardness, tensile strength, and cell survival rate are all lower than those of Examples 1-3. This indicates that the magnesium alloy composite material of the present invention is superior to traditional medical magnesium alloys in terms of mechanical properties and is less prone to breakage during use. Although the tensile strength of the gun core prepared in Comparative Example 2 is better than that of Examples 1-3, its hardness, corrosion rate, and cell survival rate are all lower than those of Examples 1-3. This indicates that traditional medical stainless steel materials are prone to breakage during use, are not easily degraded in the human body, and can damage human cells. Although the hardness and tensile strength of Comparative Example 3 are both better than those of Examples 1-3, it still has a risk of breakage in the bone suture operating environment. Furthermore, due to its low corrosion rate and cell survival rate, it indicates that traditional medical titanium alloy materials are not easily degraded in the human body and can damage human cells, increasing the need for a second surgery to remove the needle. Risks associated with the core: Comparative Example 4 used a monolithic homogeneous core prepared with a hard needle component (Mg-4Li-10Sc-2Ti@1.5MBene). Although its tensile strength was high, it lacked the flexible structure of the soft needle component, making it unsuitable for the bending operations of tendon suturing and prone to overall fracture during surgery. Comparative Example 5 used a monolithic sheet-like core prepared with a soft needle component (Mg-20Li-2Sc-0.5Ti@0.5MBene). Although its elongation was improved, its strength was low, making the core unsuitable for surgical operations. Comparative Example 6 adjusted the element content. Since the contents of Sc, Ti, and MBene exceeded the scope of this invention, the core hardness and tensile strength both decreased. Comparative Example 7 did not add Li. The hard needle hardness and tensile strength decreased by 34.6% and 33.1% respectively compared to Example 1, demonstrating that the key role of Li in the toughness of α-Mg solid solution was missing, and the material brittleness increased significantly. Comparative Example 8 did not add Sc. The corrosion rate of the soft needle increased to 0.093 mg / cm. 2 / day, and the hardness and tensile strength of the hard needle decreased, indicating that Sc's contribution to the formation of the passivation layer and precipitation strengthening is irreplaceable; Comparative Example 9, without the addition of Ti, both the hardness and tensile strength of the gun core decreased, confirming that the fine grain strengthening effect of Ti failed; Comparative Example 10, without the addition of MBene, the tensile strength of the hard needle decreased by 13.4%, and the crack propagation rate of the soft needle accelerated in the fatigue cycle test, proving that the lack of MBene's effect on interfacial bonding and crack inhibition leads to a decrease in the tensile strength of the alloy; Comparative Example 11, with the cold isostatic pressing pressure increased to 500 MPa, microcracks were generated inside the material, and both the hardness and tensile strength of the gun core decreased, indicating that high pressure destroyed the integrity of particle bonding; Comparative Example 12, with the calcination temperature reduced to 600℃, the alloy was not sufficiently densified, the porosity was >15%, the strength of the hard needle decreased, and the corrosion rate increased by 29.4%, confirming that low-temperature calcination caused structural defects. Comparative Examples 1-5 demonstrate that gradient composition design is a necessary condition for balancing the high strength of the hard needle section and the high toughness of the soft needle section; Comparative Examples 6-10 demonstrate that the quaternary synergy of Li, Sc, Ti, and MBene is indispensable, and the absence of any one element will lead to a significant deterioration in mechanical or corrosion resistance; Comparative Examples 11-12 demonstrate that strict limitation of process parameters is the key to ensuring material densification and performance stability.

[0110] In summary, the magnesium alloy core for rotator cuff repair surgical suture gun prepared by this invention achieves a smooth transition in material properties, meeting the differentiated mechanical performance requirements of different areas. Its high strength and hardness of the hard needle section ensures it is firmly fixed inside the suture gun without detachment; the good biocompatibility of the soft needle section allows it to be absorbed by the body after breakage, eliminating the need for secondary surgery to remove it, thus avoiding the problem of traditional cores failing to degrade and remaining in the body for a long time. The gradient material design between the hard and soft needle sections effectively solves the problem of stress concentration and high breakage risk at the interface of existing rotator cuff suture gun cores.

[0111] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention 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 substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A magnesium alloy barrel core for a rotator cuff repair surgical suturing gun, characterized by, The gun core comprises a hard needle part, a transition zone and a soft needle part; the diameter of the hard needle part is 4-6 mm, the length is 200-220 mm, and the shape is a thin rod; the diameter of the transition zone is 2-6 mm, the length is 20-30 mm, and the shape is a ladder; the width of the soft needle part is 2-4 mm, the length is 50-60 mm, the thickness is 0.5 mm, and the shape is a sheet; The gun core material is Mg-Li-Sc-Ti@MBene alloy; in terms of weight percentage, the hard needle part contains Li 4 wt.%, Sc 10 wt.%, Ti 2 wt.%, MBene 1.5 wt.%, and the balance is Mg; the soft needle part contains Li 20 wt.%, Sc 2 wt.%, Ti 0.5 wt.%, MBene 0.5 wt.%, and the balance is Mg; the transition zone gradually increases the content of Li from 4 wt.% to 20 wt.%, gradually reduces the content of Sc from 10 wt.% to 2 wt.%, gradually reduces the content of Ti from 2 wt.% to 0.5 wt.%, gradually reduces the content of MBene from 1.5 wt.% to 0.5 wt.%, and the balance is Mg; The preparation method of the magnesium alloy gun core for the rotator cuff repair surgery suture gun comprises the following steps in sequence: S1, preparing MBene Take (Mo 2 / 3 Y 1 / 3 )2AlB2 and add a 40 wt.% HF solution, etch at 35~60℃ for 16 h, wash 3~5 times with deionized water, add 10~20 mL of 2 mol / L TMAOH solution, stir at 3~5℃ for 1~5 h, wash 3~5 times with anhydrous ethanol, centrifuge at 3500~10500 rpm for 15~30 min, and freeze-dry to obtain MBene; S2, preparing Mg-Li-Sc-Ti@MBene alloy 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, 1-10 g of binder is added, cold isostatic pressing is performed at room temperature, and then the product is placed in a muffle furnace for calcination to obtain Mg-Li-Sc-Ti@MBene alloy; The pressure during the cold isostatic pressing is 200-350 MPa, and the treatment time is 40-60 min; The calcination temperature is 700-850℃, the time is 40-60 min, and the heating rate is 2-5℃ / min; S3, preparing the suture gun core The Mg-Li-Sc-Ti@MBene alloy is cut into a cylinder with a length of 275-310 mm, annealed at 250-300℃ for 0.5-3 h, then placed in an extrusion cylinder for extrusion, water-cooled at 20-30℃ for 20-40 min, taken out, placed in a numerical control machine tool, and processed into the shape of the suture gun core, then the surface impurities are cleaned with anhydrous ethanol for 3-5 min to obtain the suture gun core.

2. The method for preparing a magnesium alloy gun core for a rotator cuff repair surgical suture gun according to claim 1, characterized in that, The preparation method of the magnesium alloy gun core for the rotator cuff repair surgery suture gun comprises the following steps in sequence: S1, preparing MBene Take (Mo 2 / 3 Y 1 / 3 )2AlB2 and add a 40 wt.% HF solution, etch at 35~60℃ for 16 h, wash 3~5 times with deionized water, add 10~20 mL of 2 mol / L TMAOH solution, stir at 3~5℃ for 1~5 h, wash 3~5 times with anhydrous ethanol, centrifuge at 3500~10500 rpm for 15~30 min, and freeze-dry to obtain MBene; S2, preparing Mg-Li-Sc-Ti@MBene alloy 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, 1-10 g of binder is added, cold isostatic pressing is performed at room temperature, and then the product is placed in a muffle furnace for calcination to obtain Mg-Li-Sc-Ti@MBene alloy; The pressure during the cold isostatic pressing treatment is 200-350 MPa, and the treatment time is 40-60 min; The calcination temperature is 700-850℃, the time is 40-60 min, and the temperature rising rate is 2-5℃ / min; S3, preparing a suture gun core The Mg-Li-Sc-Ti@MBene alloy is cut into a cylinder with a length of 275-310 mm, annealed at 250-300℃ for 0.5-3 h, then placed in an extrusion cylinder for extrusion, water-cooled at 20-30℃ for 20-40 min, taken out, and placed in a numerical control machine tool to process the shape of the suture gun core, then cleaned with anhydrous ethanol for 3-5 min to remove surface impurities, and the suture gun core is obtained.

3. The method of claim 2, wherein the magnesium alloy barrel core for a rotator cuff repair surgery suturing gun is prepared by the steps of: a) preparing a magnesium alloy barrel core by a method according to any one of claims 1 to 2; b) coating the magnesium alloy barrel core with a coating layer; and c) polishing the magnesium alloy barrel core coated with the coating layer. In step S1, the (Mo 2 / 3 Y 1 / 3 )2AlB2 and the HF solution with a mass fraction of 40 wt.% have a mass-volume ratio of (1-2):(10-20) g / mL.

4. The method of claim 2, wherein the magnesium alloy barrel core for a rotator cuff repair surgery suturing gun is prepared by the steps of: preparing a magnesium alloy barrel core for a rotator cuff repair surgery suturing gun; and performing a surface treatment on the magnesium alloy barrel core for a rotator cuff repair surgery suturing gun. In step S1, the temperature during the freeze-drying is -10-5℃, and the time is 12-36 h.

5. The method of manufacturing a magnesium alloy barrel for a rotator cuff repair surgical stitching gun according to claim 2, wherein In step S2, the binder is one or more of phenol formaldehyde resin, magnesium aluminum silicate, polyvinyl chloride, 107 glue, white latex, and sodium silicate.

6. The method of manufacturing a magnesium alloy barrel for a rotator cuff repair surgical stitching gun according to claim 2, wherein In step S3, the extrusion ratio is 10-16, the extrusion rate is 1-5 m / min, and the temperature is 300-400℃.

Images