Single-crystal magnesium alloy wire for losing weight by embedding catguts in acupoints and preparation method of single-crystal magnesium alloy wire

Abstract

The invention discloses a single-crystal magnesium alloy wire for acupoint catgut embedding and weight losing and a preparation method of the single-crystal magnesium alloy wire, the chemical composition expression of the single-crystal magnesium alloy wire is Mg-yM-zR, in the formula, y and z represent the mass fraction of M and the mass fraction of R in magnesium alloy respectively, y is larger than or equal to 1.2 and smaller than or equal to 1.7, z is larger than or equal to 0.3 and smaller than or equal to 0.8, and the balance is Mg; m is one of Sr, Ce and Co, and R is one of Ge, Sm and Dy; the wire is prepared through the processes of smelting and casting, homogenizing treatment, hot extrusion, multi-pass cold drawing, intermediate annealing and zone smelting and directional solidification, and has uniform and controllable degradation rate, excellent mechanical property and biocompatibility; after the catgut embedding slimming agent is embedded into the acupuncture point of a human body, fat metabolism is promoted through mild and lasting physical stimulation and chemical ion regulation, intergranular corrosion and premature fracture caused by a polycrystalline structure are avoided, and the safety and durability of a catgut embedding slimming therapy are improved.

Description

Technical Field

[0001] This invention belongs to the field of medical material preparation, and relates to a single-crystal magnesium alloy wire for acupoint embedding weight loss and its preparation method. Background Technology

[0002] Obesity is a pathological state caused by excessive fat accumulation due to energy intake exceeding expenditure. Based on etiology and pathogenesis, it is divided into two main categories: simple obesity and secondary obesity. Most commonly seen obesity is simple obesity, which not only affects quality of life and physical appearance but also serves as a risk factor for various diseases such as hypertension, atherosclerosis, and coronary heart disease, seriously threatening human health. Currently, Western medicine's clinical treatments for this disease mainly include medication, surgery, diet, and exercise, but these are often not accepted by patients due to significant side effects, high risks, or difficulty in adhering to the treatment regimen. Acupoint embedding therapy is an innovative therapy that has gradually developed in Traditional Chinese Medicine in recent years. It is an extension and development of acupuncture, possessing the triple effects of needles, threads, and acupoints, and can be effectively used for weight loss treatment. Currently, the materials used for thread embedding weight loss on the market have evolved from the initial catgut sutures to polyglycolic acid glycolic acid PGLA (medical-grade collagen). PGLA threads are high-molecular-weight polymer threads that are eventually excreted from the body as water and carbon dioxide after implantation. However, due to their rapid degradation rate, they cannot maintain sustained stimulation intensity at specific acupoints, resulting in short treatment cycles, easy rebound, and the need for multiple implantations, greatly increasing the patient's pain and financial burden.

[0003] Magnesium and its alloys, as a new generation of biodegradable metallic materials, possess excellent biocompatibility and mechanical properties. Magnesium is an essential macro-element for the human body, widely participating in over 300 enzymatic reactions and playing a crucial role in life activities such as energy metabolism, nucleic acid and protein synthesis. Theoretically, applying magnesium alloys to thread embedding for weight loss could combine the physical expansion stimulation during degradation with the biochemical regulatory effects of magnesium ions, achieving a dual long-lasting stimulation of "physical + chemical" for superior results. However, the application of magnesium alloys in thread embedding for weight loss currently faces numerous technical bottlenecks. Existing related thread embedding materials and technologies all have varying degrees of defects. For example, Chinese invention patent application number 201410841415.1 discloses a single-crystal magnesium alloy biodegradable material that can eliminate the influence of grain boundaries and precipitation on relative corrosion performance, achieving uniform corrosion. However, large single-crystal magnesium has poor mechanical properties, making it impossible to plastically deform and cold-draw, limiting the development of medical implants. Chinese invention patent application number 201910091354.4 discloses a metallic thread embedding material that can achieve weight loss without rebound for 6 months. However, polycrystalline materials are prone to local corrosion due to the energy difference between grain boundaries and grains, leading to premature brittle fracture. The fracture surface may also irritate the tissue and cause discomfort. Chinese invention patent application No. 201910338989.X discloses an oxidized regenerated cellulose fat-dissolving thread with functions such as physical massage and antibacterial properties, but it has poor mechanical properties and is easy to bend during implantation, making it impossible to accurately and effectively stimulate acupoints. The World's Latest Medical News Digest 2019, 19(08):176-177 records that Bo's abdominal acupuncture uses catgut sutures to reduce waist and hip circumference, but it needs to be re-implanted every 7 days, increasing patient pain and infection risk.

[0004] Based on this, the present invention aims to provide a single-crystal magnesium alloy wire that, when implanted in the human body, can promote fat metabolism through gentle and lasting physical stimulation and chemical ion regulation. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention aims to provide a single-crystal magnesium alloy wire for acupoint embedding weight loss and its preparation method. The chemical composition of the single-crystal magnesium alloy wire is expressed as: Mg-yM-zR, where y and z represent the mass fractions of M and R in the magnesium alloy, respectively, 1.2≤y≤1.7, 0.3≤z≤0.8, and the balance is Mg; M is one of Sr, Ce, and Co, and R is one of Ge, Sm, and Dy. The wire is prepared through melting and casting, homogenization treatment, hot extrusion, multi-pass cold drawing and intermediate annealing, and zone melting and directional solidification processes, exhibiting a uniform and controllable degradation rate, excellent mechanical properties, and biocompatibility. After being embedded in acupoints, it promotes fat metabolism through gentle and lasting physical stimulation and chemical ion regulation, avoiding intergranular corrosion and premature fracture caused by polycrystalline structures, thus improving the safety and durability of acupoint embedding weight loss therapy.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A single-crystal magnesium alloy wire for acupoint embedding weight loss has the chemical composition formula: Mg-yM-zR, where y and z represent the mass fractions of M and R in the magnesium alloy, respectively, 1.2≤y≤1.7, 0.3≤z≤0.8, and the balance is Mg; M is one of Sr, Ce, and Co, and R is one of Ge, Sm, and Dy.

[0007] This invention also provides a method for preparing a single-crystal magnesium alloy wire for acupoint embedding weight loss, comprising the following steps in sequence: S1. According to the proportion, high-purity magnesium, M metal powder and Mg-R master alloy are placed in a high-purity copper crucible. The medium frequency power supply is turned on and the Mg-yM-zR alloy is melted in the protective atmosphere of argon using the cooling crucible suspension melting method. After the melting is completed, the melt is cast into a cylindrical copper mold preheated to 250°C to obtain Mg-yM-zR alloy ingot. S2. After holding the above alloy ingot at 400~450℃ for 12~24 h, perform water quenching treatment. S3. After the water-quenched ingot is de-skinned, it is preheated to 350~400℃ and hot-extruded to obtain a bar with a diameter of 2~5mm. S4. Perform multiple cold drawing operations on the bar, with the deformation amount controlled at 10~20% in each pass. When the total deformation amount reaches 40~60%, perform intermediate annealing. Repeat this process until the wire diameter reaches 0.02~0.5 mm. S5. Place the wire in a split-type multi-temperature zone rotary tube furnace (which can generate a stable axial temperature gradient). Under an inert atmosphere, place the starting end of the wire in the high-temperature zone, the middle section in the medium-temperature zone, and the ending end in the low-temperature zone. The lengths of the starting end, middle section, and ending end of the wire are the same. After holding at the temperature for 12~24 h, cool it to room temperature with the furnace to obtain a wire with a quasi-single crystal at the starting end. S6. Place the quasi-single crystal wire at the starting end in a vacuum chamber. Under an inert atmosphere, position the laser spot at the junction of the quasi-single crystal and the starting point of the polycrystalline segment to form a molten pool. Move the laser spot to the end of the wire at a speed of 1-10 mm / min under 200-300W. Use cooling circulating water to directionally solidify the molten pool area to obtain a single crystal magnesium alloy wire. S7. The monocrystalline magnesium alloy wire is cleaned, polished, and cut, and then sterilized with ethylene oxide or gamma rays to obtain monocrystalline magnesium alloy wire for acupoint embedding weight loss.

[0008] As a limitation of the preparation method of the present invention, in step S1, the power supply frequency is 10~50 Hz, the melting temperature is 680~700 ℃ and the melting time is 5~15 min when the cooling crucible is suspended for melting, the flow rate of the cooling water in the crucible water channel is 5~10 m / s, the water pressure is 0.5~0.8 MPa and the inlet water temperature is 15~25℃.

[0009] As a second limitation of the preparation method of the present invention, in step S2, the water quenching medium is an aqueous solution of polyalkylene glycol with a mass fraction of 5~30 wt.%, and the water quenching time is 10~15 s.

[0010] As a third limitation of the preparation method of the present invention, in step S4, the temperature of the intermediate annealing is 250~300℃ and the time is 15~30 min.

[0011] As a fourth limitation of the preparation method of the present invention, in step S5, the temperature of the high-temperature zone is 550~590℃, the temperature of the medium-temperature zone is 400~450℃, and the temperature of the low-temperature zone is 150~200℃; the gradient value of the temperature gradient field is 20~30 K / cm.

[0012] The high-temperature zone is below the solidus temperature of the metal wire but sufficient to trigger secondary recrystallization. If the temperature is below this, secondary recrystallization will be difficult or impossible to occur; if the temperature is above this, the material will overheat or melt.

[0013] As a fifth limitation of the preparation method of the present invention, in step S7, the single crystal magnesium alloy wire is cut into lengths of 1~2 cm during the cutting process.

[0014] This invention first utilizes the driving force of a temperature gradient to form a seed crystal with optimal orientation at the starting end of a magnesium alloy. Specifically: when the wire is placed in a split-type multi-temperature zone rotary tube furnace, with the starting end in the high-temperature zone, the middle section in the medium-temperature zone, and the ending end in the low-temperature zone, and the lengths of the wire at the starting, middle, and ending ends being the same; in the high-temperature zone, a few grains with optimal orientation (whose basal plane or rapid growth direction is parallel to the wire axis) will break through the pinning force and grow abnormally; in the medium-temperature zone, a certain degree of normal grain growth will occur, but secondary recrystallization has not yet been activated, serving as a temperature buffer and microstructure transition; in the low-temperature zone, recovery and primary recrystallization mainly occur, forming fine, uniform equiaxed grains, which provide the consumed matrix for subsequent secondary recrystallization. The grain boundaries of the "superior" grains in the high-temperature zone migrate towards the low-temperature end under the driving force of the temperature gradient, absorbing all the pinned fine grains in front, ultimately forming a "quasi-single crystal" segment with a highly consistent crystallographic orientation at the starting part of the wire. Subsequently, laser remelting is employed: the laser spot is precisely positioned at the boundary between the end of the "quasi-single crystal" segment and the beginning of the polycrystalline segment, forming a tiny molten pool at the spot. This ensures close contact between the molten pool front (solid-liquid interface) and the unmelted "quasi-single crystal" segment. The laser spot is then moved at a constant, slow speed, allowing the molten pool to gradually advance from the "quasi-single crystal" segment towards the end of the wire (polycrystalline segment). Cooling circulating water assists in directional solidification of the molten pool region, ultimately allowing the molten pool to sweep across the remaining polycrystalline portion to the end of the wire, resulting in a magnesium alloy wire with a single-crystal structure. During this process, the liquid metal at the molten pool front is in close contact with the solid "quasi-single crystal" segment. The "quasi-single crystal" segment acts as a crystal growth template, its atomic arrangement information being directly copied into the newly solidified metal, ensuring a completely consistent crystallographic orientation between the newly solidified portion and the "quasi-single crystal" segment. Simultaneously, laser melting eliminates internal defects and purifies the melt, ultimately resulting in a magnesium alloy wire with not only high purity but also a near-perfect single-crystal structure. This approach solves two key problems in the preparation of single-crystal wires: nucleation control and growth rate. By utilizing secondary recrystallization through a temperature gradient to form quasi-single crystals, the randomness of liquid-phase nucleation is avoided, enabling the preparation of single-oriented nuclei. Furthermore, the extremely high interface migration rate of laser melting and directional solidification (typically several orders of magnitude faster than solid-state grain boundary migration) enables rapid preparation of single-crystal wires. This process combines the advantages of controllable orientation and crystal integrity of solid-state methods with the efficiency and speed of liquid-phase methods, providing a highly promising technical path for the preparation of high-quality, engineered single-crystal magnesium alloy wires.

[0015] The single-crystal magnesium alloy wire prepared by this invention achieves an integrated effect of physical stimulation, biodegradability, and ion biological effects when used for wire embedding weight loss, as detailed below: (a) Degradability and biosafety 1. This monocrystalline magnesium alloy wire has low hydrogen evolution and high biocompatibility. Compared with polycrystalline magnesium alloy, the monocrystalline structure eliminates the grain boundary, a rapid corrosion channel, making its degradation more uniform and slow, avoiding a sharp increase in local pH value and concentrated accumulation of hydrogen. This significantly reduces adverse reactions such as subcutaneous emphysema and bulging, and improves treatment comfort and safety. 2. This single-crystal magnesium alloy has an ideal degradation curve, which can precisely match the treatment cycle. (1) High initial strength: In the early stage of wire embedding, the wire maintains high mechanical integrity and can provide continuous and powerful physical stimulation; (2) Mid-term degradation stability: During the mid-term treatment, the silk material degrades uniformly at a controllable rate, continuously releasing magnesium ions and functional alloy ions, providing stable chemical stimulation, and achieving long-term gentle conditioning; (3) No foreign body residue in the later stage: In the later stage of treatment (usually several months), the silk material is completely degraded into magnesium ions and other products, which are naturally absorbed and metabolized by the human body, leaving no foreign body residue. This avoids the long-term rejection or encapsulation reaction that may be caused by traditional thread materials. This continuous stimulation is equivalent to the "long-term needle retention" of traditional acupuncture, which can continuously dredge the meridians, harmonize qi and blood, inhibit excessive gastrointestinal motility, reduce appetite, and promote the body's metabolism.

[0016] (ii) Suitable mechanical properties and minimally invasiveness The monocrystalline magnesium alloy wire has moderate mechanical strength, allowing for smooth puncture. Its high strength and toughness ensure it will not bend or break during the embedding procedure, enabling easy and precise insertion into the intended acupoint depth. The rapid puncture process reduces tissue damage, significantly alleviating patient pain and bleeding, and improving the patient's overall experience.

[0017] (III) The combined pharmacological effects of functional alloying elements (1) Zinc, strontium and other elements are key cofactors in the process of coagulation factors and platelet activation; they play a role in the local area of ​​the needle hole, rapidly promote blood coagulation, effectively reduce subcutaneous bruising and bleeding, and accelerate the healing of the needle hole; (2) The functional ions formed by M and R elements can inhibit the release of pro-inflammatory cell (RAW264.7 M1) factors and regulate the transformation of immune cells to anti-inflammatory phenotypes. At the same time, magnesium ions themselves have mild anti-inflammatory properties. Together, they can effectively reduce the acute inflammatory response after thread embedding, prevent secondary pain and tissue adhesion, and create a good local environment for the acupoints to continue to play their role.

[0018] (iv) Deep regulation of the nervous and endocrine systems (1) Magnesium ions are cofactors of hundreds of enzymes in the body. Supplementing magnesium helps improve leptin sensitivity. Leptin is a key hormone that inhibits appetite. Obese patients often have leptin resistance. Through the regulation of magnesium ions, the brain can be restored to normal reception of leptin signals, thereby transmitting a signal of fullness to the brain, fundamentally inhibiting appetite and reducing calorie intake. (2) Regulate neuropeptide Y levels and soothe emotions; neuropeptide Y is a powerful neurotransmitter that promotes appetite and food intake, especially when its level increases under stress, leading to emotional eating; magnesium ions have the effect of stabilizing the nervous system and relieving anxiety and stress; by regulating the function of the nervous system, the level of neuropeptide Y can be indirectly reduced, thereby reducing the desire for food, especially the desire for high-sugar and high-fat foods, soothing the patient's emotions from the perspective of the nervous system and breaking the vicious cycle of "stress-eating-obesity"; (3) Continuous acupoint stimulation effect; During the entire process of degradation of monocrystalline magnesium alloy wire, it acts as a "foreign object" in the acupoint, producing a continuous and mild "needle sensation" stimulation to the body. This long-term stimulation is conducted through the meridians, regulating the autonomic nerve function, inhibiting gastrointestinal motility, and promoting the body's metabolism, thereby achieving the goal of weight loss.

[0019] The above-mentioned technical solution of the present invention is as a whole, and the various steps are closely related and mutually influential, which together determine the morphological characteristics and performance of the product.

[0020] The above technical solution has the following advantages or beneficial effects: 1. The magnesium alloy wire obtained by this invention has a single crystal structure. After being implanted into the human body, it will corrode uniformly and degrade slowly, avoiding a sharp increase in local pH value and concentrated accumulation of hydrogen. Furthermore, the appropriate components can be selected according to the differences in the treatment cycle required by patients with different degrees of obesity, so that the implanted thread can be completely degraded within the treatment cycle. 2. This invention uses monocrystalline magnesium alloy wire with moderate mechanical strength and plasticity, eliminating the need for embedding cannulas and allowing direct and smooth puncture of acupoints, greatly reducing patient pain and the risk of bleeding. 3. The metal ions generated during the degradation process of the alloying elements added in this invention can promote blood clotting, anti-inflammation, and tissue repair at the puncture site; magnesium ions can effectively improve leptin resistance, reduce the patient's appetite, and soothe the patient's emotions by regulating the level of neuropeptide Y, thereby achieving the purpose of weight loss. 4. The preparation process of this invention is simple, environmentally friendly, has a short production cycle, and is suitable for large-scale production.

[0021] This invention is applicable to the preparation of monocrystalline magnesium alloy wires for acupoint embedding weight loss.

[0022] 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

[0023] Figure 1 The hydrogen evolution test curves of the filaments prepared in Example 1 and Comparative Examples 2 and 3 of this invention after being soaked in 0.9 wt.% physiological saline for 12 weeks are shown. Figure 2 The graph shows the metal ion release rate curves of the silk materials prepared in Example 1 and Comparative Examples 4 and 5 of the present invention after being soaked in 0.9 wt.% physiological saline for 12 weeks. Figure 3 The above are quasi-in-situ scanning images of magnesium alloy wire from polycrystalline to single-crystal structure in Example 2 of the present invention, wherein: a is the metallographic scanning image of polycrystalline wire obtained in step S4, b is the metallographic scanning image of wire recrystallized once in the middle temperature region in step S5, c is the metallographic scanning image of quasi-single-crystal formed in the high temperature region in step S5, and d is the metallographic scanning image of single-crystal wire obtained in step S6. Figure 4 The stress-strain curves of the materials prepared in Embodiment 2 and Comparative Examples 6 and 7 of the present invention are shown. Figure 5 The image shows the fluorescence staining of M1 type RAW264.7 cells with the extract of the materials prepared in Example 3 and Comparative Example 1 of this invention. Figure 6 This is a statistical diagram of EdU-positive cells in M1 type RAW264.7 cells obtained from the extracts of the materials prepared in Example 3 and Comparative Example 1 of the present invention. Figure 7 This is a comparison chart showing the changes in plasma neuropeptide Y content in rats treated with the monocrystalline magnesium alloy wire prepared in Example 3 of this invention and in the model group rats after 12 weeks of treatment. Detailed Implementation

[0024] 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.

[0025] 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.

[0026] Example 1 This embodiment prepares a Mg-1.7Sr-0.3Ge (by mass percentage: Sr: 1.7 wt.%, Ge: 0.3 wt.%, balance Mg) single-crystal magnesium alloy wire for acupoint embedding for weight loss. The preparation process and steps of the single-crystal magnesium alloy wire are as follows: S1. Place 92.3 g of high-purity magnesium, 1.7 g of Sr metal powder, and 6 g of Mg-Ge (select Mg-5 wt.%Ge) master alloy in a high-purity copper crucible. Start the medium-frequency power supply with a frequency of 10 Hz. Under the protective atmosphere of argon, use the cooling crucible suspension melting method to melt the alloy. The melting temperature is 680℃, the melting time is 5 min, the flow rate of cooling water in the crucible water channel is 5 m / s, the water pressure is 0.5 MPa, and the inlet water temperature is 15℃. After melting, pour the melt into a cylindrical copper mold preheated to 250℃ to obtain a Mg-1.7Sr-0.3Ge alloy ingot. S2. After holding the above alloy ingot at 400℃ for 12 h, it is subjected to water quenching treatment. The water quenching medium is a 5 wt.% polyalkylene glycol aqueous solution, and the water quenching time is 10 s. S3. After water quenching, the ingot is preheated to 350°C after removing the outer skin and then hot extruded to obtain a bar with a diameter of 5 mm. S4. Perform multiple cold drawing operations on the bar, with the deformation amount controlled at 10% in each pass. When the total deformation amount reaches 40%, perform intermediate annealing at 250℃ for 15 minutes. Repeat this process until the wire diameter reaches 0.5 mm. S5. Place the wire in a split-type multi-temperature zone rotary tube furnace (which can generate a stable axial temperature gradient) with a temperature gradient of 20 K / cm. Under an inert atmosphere, place one end (starting end) of the wire in the high-temperature zone (550℃), the middle section in the medium-temperature zone (400℃), and the other end (ending end) in the low-temperature zone (150℃). The lengths of the wire at the starting end, middle section, and ending end are the same. After holding at this temperature for 12 h, cool it to room temperature with the furnace to obtain a wire with a quasi-single crystal at the starting end. S6. Place the quasi-single crystal wire at the starting end in a vacuum chamber. Under an inert atmosphere, position the laser spot at the junction of the quasi-single crystal and the starting point of the polycrystalline segment. At 200 W, generate a small molten pool at the spot, ensuring that the leading edge of the molten pool (solid-liquid interface) is in close contact with the unmelted "quasi-single crystal". Move the laser spot at a speed of 1 mm / min, so that the molten pool moves from the quasi-single crystal segment to the tail end (polycrystalline segment) of the wire. Use circulating cooling water to directionally solidify the molten pool area. The molten pool sweeps across the entire remaining polycrystalline part until the end of the wire, resulting in a magnesium alloy wire with a single crystal structure. S7. Clean, polish, and cut the monocrystalline magnesium alloy wire (1 cm) and then sterilize it with ethylene oxide to obtain monocrystalline magnesium alloy wire for acupoint embedding weight loss.

[0027] Example 2 This embodiment prepares a Mg-1.5Ce-0.5Sm (by mass percentage: Ce: 1.5 wt.%, Sm: 0.5 wt.%, balance Mg) single-crystal magnesium alloy wire for acupoint embedding weight loss. The preparation process and steps of the single-crystal magnesium alloy wire are as follows: S1. Place 96 g of high-purity magnesium, 1.5 g of Ce metal powder, and 2.5 g of Mg-Sm (Mg-20 wt.%Sm) master alloy in a high-purity copper crucible. Start the medium-frequency power supply with a frequency of 30 Hz. Under the protective atmosphere of argon, use the cooling crucible suspension melting method to melt the alloy. The melting temperature is 690℃, the melting time is 10 min, the flow rate of cooling water in the crucible water channel is 7 m / s, the water pressure is 0.7 MPa, and the inlet water temperature is 20℃. After melting, pour the melt into a cylindrical copper mold preheated to 250℃ to obtain a Mg-1.5Ce-0.5Sm alloy ingot. S2. After holding the above alloy ingot at 425℃ for 18 h, it is subjected to water quenching treatment. The water quenching medium is a polyalkylene glycol aqueous solution with a mass fraction of 18 wt.%, and the water quenching time is 13 s. S3. Preheat the water-quenched ingot skin to 375℃ and perform hot extrusion to obtain a bar with a diameter of 3 mm. S4. Perform multiple cold drawing operations on the bar, with the deformation amount controlled at 15% per pass. When the total deformation amount reaches 50%, perform intermediate annealing at 275℃ for 25 minutes. Repeat this process until the wire diameter reaches 0.15 mm. S5. Place the wire in a split-type multi-temperature zone rotary tube furnace (which can generate a stable axial temperature gradient) with a temperature gradient of 25 K / cm. Under an inert atmosphere, place one end (starting end) of the wire in the high-temperature zone (570℃), the middle section in the medium-temperature zone (425℃), and the other end (ending end) in the low-temperature zone (175℃). The lengths of the wire at the starting end, middle section, and ending end are the same. After holding at this temperature for 18 h, cool it to room temperature with the furnace to obtain a wire with a quasi-single crystal at the starting end. S6. Place the quasi-single crystal wire at the starting end in a vacuum chamber. Under an inert atmosphere, position the laser spot at the junction of the quasi-single crystal and the starting point of the polycrystalline segment. At 250 W, generate a small molten pool at the spot, ensuring that the leading edge of the molten pool (solid-liquid interface) is in close contact with the unmelted "quasi-single crystal". Move the laser spot at a speed of 5 mm / min to advance the molten pool from the quasi-single crystal segment to the tail end (polycrystalline segment) of the wire. Use circulating cooling water to directionally solidify the molten pool area. The molten pool sweeps across the entire remaining polycrystalline part until the end of the wire, resulting in a magnesium alloy wire with a single crystal structure. S7. The monocrystalline magnesium alloy wire is cleaned, polished, and cut (1.5 cm), and then sterilized with γ-rays to obtain monocrystalline magnesium alloy wire for acupoint embedding weight loss.

[0028] Example 3 This embodiment prepares a Mg-1.2Co-0.8Dy (by mass percentage: Co: 1.2 wt.%, Dy: 0.8 wt.%, balance Mg) single-crystal magnesium alloy wire for acupoint embedding for weight loss. The preparation process and steps of the single-crystal magnesium alloy wire are as follows: S1. Place 94.8 g of high-purity magnesium, 1.2 g of Co metal powder, and 4 g of Mg-Dy (select Mg-20wt.%Dy) master alloy in a high-purity copper crucible. Start the medium-frequency power supply with a frequency of 50 Hz. Under the protective atmosphere of argon, use the cooling crucible suspension melting method to melt the alloy. The melting temperature is 700 ℃, the melting time is 15 min, the flow rate of cooling water in the crucible water channel is 10 m / s, the water pressure is 0.8 MPa, and the inlet water temperature is 25 ℃. After melting, pour the melt into a cylindrical copper mold preheated to 250 ℃ to obtain a Mg-1.2Co-0.8Dy alloy ingot. S2. After holding the above alloy ingot at 450℃ for 24 h, it is subjected to water quenching treatment. The water quenching medium is 30 wt.% polyalkylene glycol aqueous solution, and the time is 15 s. S3. Preheat the water-quenched ingot skin to 400℃ and perform hot extrusion to obtain a bar with a diameter of 2 mm. S4. Perform multiple cold drawing operations on the bar, with the deformation amount controlled at 20% in each operation. When the total deformation amount reaches 60%, perform intermediate annealing at 300℃ for 30 minutes. Repeat this process until the wire diameter reaches 0.02 mm. S5. Place the wire in a split-type multi-temperature zone rotary tube furnace (which can generate a stable axial temperature gradient) with a temperature gradient of 30 K / cm. Under an inert atmosphere, place one end (starting end) of the wire in the high-temperature zone (590℃), the middle section in the medium-temperature zone (450℃), and the other end (ending end) in the low-temperature zone (200℃). The lengths of the wire at the starting end, middle section, and ending end are the same. After holding at this temperature for 24 h, cool it to room temperature with the furnace to obtain a wire with a quasi-single crystal at the starting end. S6. Place the quasi-single crystal wire at the starting end in a vacuum chamber. Under an inert atmosphere, position the laser spot at the junction of the quasi-single crystal and the starting point of the polycrystalline segment. At 300 W, generate a small molten pool at the spot, ensuring that the leading edge of the molten pool (solid-liquid interface) is in close contact with the unmelted "quasi-single crystal". Move the laser spot at a speed of 10 mm / min to advance the molten pool from the quasi-single crystal segment to the tail end (polycrystalline segment) of the wire. Use circulating cooling water to directionally solidify the molten pool area. The molten pool sweeps across the entire remaining polycrystalline part until the end of the wire, resulting in a magnesium alloy wire with a single crystal structure. S7. The monocrystalline magnesium alloy wire is cleaned, polished, and cut (2 cm), and then sterilized with γ-rays to obtain monocrystalline magnesium alloy wire for acupoint embedding weight loss.

[0029] Comparative Example To investigate the influence of different methods on the performance of the product during the preparation process of this invention, the following comparative experiments were conducted. Different materials were prepared for acupoint embedding weight loss, as detailed below: Comparative Example 1 No. 00 absorbable catgut sutures were used as the material for acupoint embedding for weight loss.

[0030] Comparative Example 2 This comparative example prepares a polycrystalline high-purity magnesium wire. The preparation process is similar to that of Example 1, except that in step S1, the alloy composition is high-purity magnesium, and steps S5 and S6 are not performed.

[0031] Comparative Example 3 This comparative example prepares a single-crystal high-purity magnesium wire. The preparation process is similar to that of Example 1, except that in step S1, the alloy composition uses high-purity magnesium.

[0032] Comparative Example 4 This comparative example prepares a single-crystal high-purity titanium wire. The preparation process is similar to that of Example 1, except that in step S1, the alloy composition is high-purity titanium.

[0033] Comparative Example 5 This comparative example prepares a polycrystalline Mg-1.7Sr-0.3Ge wire. The preparation process is similar to that of Example 1, except that steps S5 and S6 are not performed.

[0034] Comparative Example 6 This comparative example prepares a polycrystalline Mg-1.5Ce-0.5Sm wire. The preparation process is similar to that in Example 2, except that steps S5 and S6 are not performed.

[0035] Comparative Example 7 This comparative example demonstrates the preparation of a single-crystal Mg-1.5Ce-0.5Sm bulk crystal. The specific preparation process is as follows: The oxide layer on the surface of the polycrystalline Mg-1.5Ce-0.5Sm ingot prepared in step S1 of Example 2 was removed, and it was placed in a high-purity graphite crucible with boron nitride coating on the inner wall. The crucible was then placed in a single crystal furnace for melting. The furnace body was divided into two temperature zones: an upper high-temperature zone (650°C) and a lower low-temperature zone (200°C). Subsequently, the crucible containing the raw material was slowly and steadily moved downward (5 mm / min) to gradually transition it from the high-temperature zone to the low-temperature zone. The pointed nascent crystal segment at the bottom of the crucible first entered the low-temperature zone and cooled, obtaining a Mg-1.5Ce-0.5Sm seed crystal. As the crucible continued to descend slowly, the molten magnesium metal would use the crystal lattice of the seed crystal as a template to continuously grow epitaxially at the solid-liquid interface, obtaining a single-crystal Mg-1.5Ce-0.5Sm bulk. The bulk with a diameter of 0.15 mm was then obtained by precision lathe machining.

[0036] Performance testing The alloys prepared in Examples 1-3 and Comparative Examples 1-7 of the present invention were subjected to a series of tests, as follows: like Figure 1 The figure shows the hydrogen evolution test curves of the wires prepared in Example 1 and Comparative Examples 2 and 3 after immersion in 0.9 wt.% physiological saline for 12 weeks. As can be seen from the figure, the magnesium alloy wire prepared in Example 1 exhibits the lowest hydrogen evolution during immersion, demonstrating good corrosion resistance. After implantation in the human body, it can prevent subcutaneous tissue bulging, thus avoiding local alkalization and inflammation. This is because the addition of Ge element in Example 1 poisons the cathode hydrogen evolution sites, inhibiting hydrogen evolution. Furthermore, due to its single-crystal structure, it tends towards uniform corrosion during immersion, significantly increasing its service life in the human body. In contrast, Comparative Examples 2 and 3 reach their maximum hydrogen evolution in weeks 5 and 6, respectively, indicating poor corrosion resistance and only maintaining stability for a short period.

[0037] like Figure 2The graph shows the metal ion leaching rate curves of the wires prepared in Example 1 and Comparative Examples 4 and 5 after immersion in 0.9 wt.% physiological saline for 12 weeks. Since the dissolution of metal ions represents the degradation of the sample, the ions dissolved from the wires prepared in Example 1 and Comparative Example 5 are mainly magnesium ions, while those dissolved in Comparative Example 4 are mainly titanium ions. Furthermore, the graph shows that the leaching rate of the wire prepared in Example 1 was almost 0 in the first two weeks, indicating that the sample remained stable and did not degrade in the early stages of corrosion. As time progressed, magnesium ions slowly dissolved, until the magnesium ion leaching rate reached 100% after 12 weeks of immersion, indicating that Example 1 was completely degraded with no foreign matter residue. While the wire prepared in Comparative Example 4 did not degrade in the first six weeks (titanium ion leaching rate was 0%), the titanium ion leaching rate did not reach 100% after 12 weeks of immersion, indicating that foreign matter residue remained in the later stages, requiring a second treatment. The magnesium ion release rate of the filament prepared in Comparative Example 5 reached 100% in the sixth week, indicating that it completed the degradation process ahead of schedule and could not meet the 12-week service life requirement.

[0038] like Figure 3 The image shown is a quasi-in-situ scanning image of the magnesium alloy wire from the present invention (Example 2), depicting the transformation from a polycrystalline to a single-crystal structure. The metallographic scanning image of the polycrystalline wire obtained after cold drawing is shown below. Figure 3 As shown in Figure a, the grain structure is relatively fine and contains a large number of grain boundaries. After the annealing and recrystallization treatment in step S5, the grains are fully recrystallized, and the grain size has increased significantly. Figure 3 b); With annealing at different temperature gradients, a small segment of single crystal gradually forms at the beginning of the wire ( Figure 3 c (right side), and then through laser remelting in step S6, a complete single-crystal structure filament is obtained ( Figure 3 d).

[0039] like Figure 4The figures show the stress-strain curves of the materials obtained in Example 2 and Comparative Examples 6 and 7 of this invention. As can be seen from the figures, the magnesium alloy wire obtained in Example 2 has a yield strength of 235 MPa and an elongation of 24.8%, meeting the requirements for both skin puncture and thread embedding (to simultaneously meet this requirement, a yield strength greater than 200 MPa and an elongation greater than 22% are needed). The magnesium alloy wire obtained in Comparative Example 6 has a yield strength of 321 MPa and an elongation of 19.5%. This is because the polycrystalline wire obtained after plastic deformation contains a large number of grain boundaries and dislocations, resulting in work hardening. Therefore, the yield strength is much greater than the standard, but the plasticity is less than 22%. Too high a yield strength can cause pain and bleeding risks to patients during skin puncture, and the low elongation makes it prone to breakage after implantation. The magnesium alloy block obtained in Comparative Example 7 has a yield strength of only 163 MPa and an elongation of 35.5%. Macroscopically, the sample is too soft, making it unable to effectively puncture the skin and prone to deformation. This is because the absence of grain boundaries prevents dislocation pile-up, allowing dislocations to slide freely within the grains, forming slip steps and resulting in low strength and high plasticity. Therefore, the magnesium alloy wire prepared in Example 2 meets both yield strength and elongation requirements. When used as a metal embedding thread inserted into acupoints, it does not undergo significant deformation, reducing stress corrosion sensitivity caused by deformation and providing long-term, stable physical stimulation to acupoints. Furthermore, unlike conventional catgut sutures, the magnesium alloy wire prepared in Example 2 does not require an embedding needle and can be directly inserted into acupoints, significantly reducing the risk of skin infection after bleeding from needle puncture.

[0040] The effects of the materials prepared in Example 3 and Comparative Example 1 on the proliferation level of M1 type RAW264.7 cells were tested. The specific test method is as follows: According to the national standard "Biological Evaluation of Medical Devices Part 1: Evaluation and Testing in the Risk Management Process" (GB / T 16886.1-2022 / ISO 10993-1) implemented by the State Administration for Market Regulation on May 1, 2023, the materials of Comparative Example 1 and Example 3 were placed in 6-well plates, and 2 mL of serum-free culture medium was added for soaking for 72 h. The extract was collected for cell treatment. The EdU cell proliferation assay was performed according to the EdU cell proliferation kit with fluor 555 instructions: cells were cultured in 96-well plates, fixed and stained with EdU 24 hours after transfection, and finally randomly photographed under an inverted fluorescence microscope and the images were saved; each group was set up with 3 biological replicates, and at least 5 different fields of view were collected from each well. ImageJ software was used to count cells and calculate the proportion of EdU-positive cells to the total number of cells. The test results are as follows. Figure 5 and Figure 6As shown in the figure, the EdU-positive cell rate in Example 3 was lower than that in Comparative Example 1, indicating that Example 3 had an inhibitory effect on the proliferation level of RAW264.7 M1 cells. RAW264.7 M1 cells secrete a large number of inflammatory factors, producing leptin resistance and other inflammations, causing metabolic disorders and obesity. Magnesium and cobalt ions can inhibit the polarization of RAW264.7 cells to the M1 type, thereby reducing the production of a large number of pro-inflammatory factors and improving metabolism. However, the catgut in Comparative Example 1 did not have such an effect.

[0041] The materials prepared in Examples 1-3 and Comparative Examples 1-3 of this invention were implanted into rats, and the rats' physical signs were observed. The specific test methods are as follows: Eighty healthy male SD rats, clean grade, 8 weeks old, were selected. Ten rats were divided into eight groups: a control group, a model group, a catgut group (Comparative Example 1), and a magnesium alloy wire embedding group (Comparative Examples 2, 3, Example 1, Example 2, and Example 3). The control group was fed a normal diet, while the other groups were fed a high-fat diet. After 8 weeks of feeding, the rats in each group were weighed. The average weight of the rats in the control group was 300 g, and the average weight of the rats in the other groups was 380 g, indicating successful model establishment. The control group and the model group served as control groups and received no treatment. The catgut group and the magnesium alloy wire embedding group underwent embedding treatment. The acupoints selected for embedding were Zusanli (ST36) and Huantiao (GB30). Because the renewal and metabolism of adipocytes is a relatively slow process, it usually takes 8-12 weeks from the initiation of metabolic regulation to the observation of stable body shape changes. A 12-week cycle ensures that the therapeutic effect deeply intervenes in the entire process of fat metabolism. The 12-week continuous intervention aims to help the body "reset" its weight set point and establish a new, healthier metabolic balance. The weight changes of rats were recorded over 12 weeks, with records taken every week. The specific results are shown in the table below: The weight change data recorded in the table above shows that within 12 weeks of implantation of the monocrystalline magnesium alloy wire prepared in Examples 1-3 of this invention into rats, the rats' weight showed a decreasing trend, indicating that using the monocrystalline magnesium alloy wire prepared in this invention for acupoint embedding can achieve the purpose of weight loss. In contrast, the catgut group in Comparative Example 1 achieved the goal of weight loss within two weeks, but due to the short degradation time of the catgut, it could no longer stimulate the acupoints in the later stages, causing the rats' weight to increase. In Comparative Examples 2 and 3, the weight change of rats reached a minimum in weeks 4 and 6, respectively, after which the weight showed an increasing trend, indicating that Comparative Examples 2 and 3 caused weight rebound in rats. In the blank group and model group without embedding treatment, the rats' weight continued to increase.

[0042] The plasma neuropeptide Y levels of rats treated with the monocrystalline magnesium alloy wire prepared in Example 3 of this invention, as well as the model group rats, were measured after 1 week, 6 weeks, and 12 weeks of treatment, respectively. The specific detection method is as follows: The rats in the two groups corresponding to the treatment cycle were decapitated, and the brain tissue was quickly dissected and weighed. Then, it was placed in a glass homogenizing tube, 1 mL of 0.5 mol / L HCl was added, and the mixture was thoroughly homogenized in an ice bath before being transferred to a plastic test tube. The test tube was placed at room temperature to allow the bioactive peptides to fully dissolve in the acid. Then, 1 mL of 0.5 mol / L NaOH was added to neutralize the acid, and the mixture was centrifuged at 4000 r / min for 10 min at 4℃. The supernatant was collected and stored at -20℃ for later testing. The content of neuropeptide Y in the hypothalamus was determined by radioimmunoassay using an SN-695B r counter.

[0043] Changes in plasma neuropeptide Y levels in rats after 12 weeks of treatment are as follows: Figure 7 As shown in the figure, after the magnesium alloy wire prepared in Example 3 was implanted into acupoints, the content of neuropeptide Y gradually decreased over time. Neuropeptide Y promotes appetite, and excessively high levels over a long period can lead to overeating, weight gain, and elevated blood triglycerides. Magnesium ions, a degradation product, exert their anti-inflammatory effects and act as an essential cofactor for insulin receptor tyrosinase. Sufficient magnesium ensures the binding of insulin to receptors on cell membranes, facilitating signal activation and transmission, thus effectively improving insulin resistance. When insulin signals return to normal, the physiological inhibition of neuropeptide Y neurons in the hypothalamus is restored, thereby systemically downregulating neuropeptide Y levels over a long period. Therefore, the magnesium alloy wire prepared in Example 3, when used for acupoint implantation, can achieve weight loss by reducing the content of neuropeptide Y in plasma from the hypothalamus.

[0044] 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 single-crystal magnesium alloy wire for acupoint embedding weight loss, characterized in that, Its chemical composition is expressed as: Mg-yM-zR, where y and z represent the mass fractions of M and R, respectively, 1.2≤y≤1.7, 0.3≤z≤0.8, and the balance is Mg; M is one of Sr, Ce, and Co, and R is one of Ge, Sm, and Dy.

2. The method for preparing a single-crystal magnesium alloy wire for acupoint embedding weight loss according to claim 1, characterized in that, Follow these steps in sequence: S1. According to the proportion, high-purity magnesium, M metal powder and Mg-R master alloy are placed in a high-purity copper crucible. The medium frequency power supply is turned on and the Mg-yM-zR alloy is melted in the protective atmosphere of argon using the cooling crucible suspension melting method. After the melting is completed, the melt is cast into a cylindrical copper mold preheated to 250°C to obtain Mg-yM-zR alloy ingot. S2. After holding the above alloy ingot at 400~450℃ for 12~24 h, perform water quenching treatment. S3. After the water-quenched ingot is de-skinned, it is preheated to 350~400℃ and hot-extruded to obtain a bar with a diameter of 2~5 mm. S4. Perform multiple cold drawing operations on the bar, with the deformation amount controlled at 10~20% in each pass. When the total deformation amount reaches 40~60%, perform intermediate annealing. Repeat this process until the wire diameter reaches 0.02~0.5 mm. S5. Place the wire in a split multi-temperature zone rotary tube furnace. Under an inert atmosphere, place the starting end of the wire in the high-temperature zone, the middle section in the medium-temperature zone, and the ending end in the low-temperature zone. The lengths of the starting end, middle section, and ending end of the wire are the same. After holding at the temperature for 12-24 hours, cool it to room temperature with the furnace to obtain a wire with a quasi-single crystal at the starting end. S6. Place the quasi-single crystal wire at the starting end in a vacuum chamber. Under an inert atmosphere, position the laser spot at the junction of the quasi-single crystal and the starting point of the polycrystalline segment to form a molten pool. Move the laser spot to the end of the wire at a speed of 1-10 mm / min under 200-300W. Use cooling circulating water to directionally solidify the molten pool area to obtain a single crystal magnesium alloy wire. S7. The monocrystalline magnesium alloy wire is cleaned, polished, and cut, and then sterilized with ethylene oxide or gamma rays to obtain monocrystalline magnesium alloy wire for acupoint embedding weight loss.

3. The method for preparing a single-crystal magnesium alloy wire for acupoint embedding weight loss according to claim 1, characterized in that, In step S1, during the suspension melting of the cooling crucible, the power frequency is 10~50 Hz, the melting temperature is 680~700℃, the melting time is 5~15 min, the flow rate of cooling water in the crucible water channel is 5~10 m / s, the water pressure is 0.5~0.8 MPa, and the inlet water temperature is 15~25℃.

4. The method for preparing a single-crystal magnesium alloy wire for acupoint embedding weight loss according to claim 1, characterized in that, In step S2, the water quenching medium is a polyalkylene glycol aqueous solution with a mass fraction of 5~30 wt.%, and the water quenching time is 10~15 s.

5. The method for preparing a single-crystal magnesium alloy wire for acupoint embedding weight loss according to claim 1, characterized in that, In step S4, the intermediate annealing temperature is 250~300℃ and the time is 15~30 min.

6. The method for preparing a single-crystal magnesium alloy wire for acupoint embedding weight loss according to claim 1, characterized in that, In step S5, the temperature of the high-temperature zone is 550~590℃, the temperature of the medium-temperature zone is 400~450℃, the temperature of the low-temperature zone is 150~200℃, and the gradient value of the temperature gradient field is 20~30 K / cm.

7. The method for preparing a single-crystal magnesium alloy wire for acupoint embedding weight loss according to claim 1, characterized in that, In step S7, during the cutting process, the single-crystal magnesium alloy wire is cut into lengths of 1-2 cm.

Images