阅读说明：本技术 一种可降解镁合金原位复合吻合钉及其制备方法 (Degradable magnesium alloy in-situ composite anastomosis nail and preparation method thereof ) 是由 马政 谭丽丽 杨柯 于 2019-01-30 设计创作，主要内容包括：本发明涉及生物医用材料技术领域,特别提供一种可降解镁合金原位复合吻合钉及其制备方法。该吻合钉为一种复合结构材料,主要分两部分,内部由强度高、塑性好的Mg-Zn-Nd镁合金组成,外部由起腐蚀保护作用的MgF<Sub>2</Sub>组成,由Mg-Zn-Nd镁合金吻合钉的外层原位复合MgF<Sub>2</Sub>而成。本发明的镁合金复合材料吻合钉,具有良好的塑性变形能力及力学强度,较慢的降解速度,优良的生物安全性,满足吻合钉在体内的植入要求,在生物体内达到医疗效果后可在体内逐步降解,避免二次手术取出。(The invention relates to the technical field of biomedical materials, and particularly provides a degradable magnesium alloy in-situ composite anastomosis nail and a preparation method thereof. The anastomosis nail is a composite structure material which is mainly divided into two parts, wherein the inside of the anastomosis nail is composed of Mg-Zn-Nd magnesium alloy with high strength and good plasticity, and the outside of the anastomosis nail is MgF with corrosion protection function 2 Consists of Mg-Zn-Nd magnesium alloy anastomosis nail outer layer in-situ compounded MgF 2 And (4) preparing the composition. The invention relates to a magnesium alloy composite material anastomosis nail,the anastomosis nail has good plastic deformation capacity and mechanical strength, slower degradation speed and excellent biological safety, meets the implantation requirement of the anastomosis nail in a body, can be gradually degraded in the body after reaching the medical effect in the body, and avoids the secondary operation taking out.)

1. The degradable magnesium alloy in-situ composite anastomosis nail is characterized in that the anastomosis nail is a composite structure material and mainly comprises two parts, wherein the inside of the anastomosis nail is composed of Mg-Zn-Nd magnesium alloy with high strength and good plasticity, and the outside of the anastomosis nail is composed of MgF with corrosion protection function₂Consists of Mg-Zn-Nd magnesium alloy anastomosis nail outer layer in-situ compounded MgF₂And (4) preparing the composition.

2. The degradable magnesium alloy in-situ composite anastomosis nail according to claim 1, characterized in that the Mg-Zn-Nd alloy anastomosis nail comprises the following chemical components in percentage by weight: zn0.2-3.0%, Nd0.2-2.3%, and Mg for the rest.

3. The degradable magnesium alloy in-situ composite anastomosis nail according to claim 2, wherein the technical indexes of the Mg-Zn-Nd magnesium alloy anastomosis nail are as follows in percentage by weight: the tensile strength range is 260-320 MPa, the yield strength range is 170-240 MPa, and the elongation percentage range is 20-33%.

4. The degradable magnesium alloy in-situ composite anastomosis nail according to claim 1, wherein MgF plays a role in corrosion protection at the outer layer₂The thickness is 1.0-3.3 μm.

5. The preparation method of the degradable magnesium alloy in-situ composite anastomosis nail according to any one of claims 1 to 4, which is characterized by comprising the following operation steps:

(1) smelting magnesium alloy from pure magnesium, Zn and Nd according to a proportion, casting the magnesium alloy into a magnesium alloy ingot, and carrying out homogenization heat treatment at the temperature of 300-450 ℃ for 3-7 h;

(2) removing surface defects and impurities from the magnesium alloy ingot in the step (1), extruding the magnesium alloy ingot into a bar with the diameter of 8-10 mm, wherein the extrusion ratio is 60-80: 1, and the extrusion temperature is 390-470 ℃;

(3) preparing the magnesium alloy bar in the step (2) into a wire with the diameter of 0.2-0.6 mm through cold drawing, and carrying out heat treatment annealing at the temperature of 280-330 ℃ for 30-120 min;

(4) preparing the magnesium alloy wire material in the step (3) into a U-shaped anastomosis nail;

(5) performing electrolytic polishing on the magnesium alloy anastomosis nail in the step (4), removing surface defects, and drying after ultrasonic cleaning;

(6) immersing the anastomosis nail in the step (5) into hydrofluoric acid for MgF₂In-situ compounding, wherein the weight concentration of hydrofluoric acid is 20-60%, the time is 3-200 h, and the treatment temperature is 20-35 ℃;

(7) and (4) ultrasonically cleaning the in-situ composite magnesium alloy anastomosis nail in the step (6), drying the anastomosis nail, and carrying out vacuum packaging.

6. The preparation method of the degradable magnesium alloy in-situ composite anastomosis nail according to claim 5, wherein in the step (4), the bending part of the U-shaped anastomosis nail is in an oval shape, the total length of the anastomosis nail is 10-15 mm, the height of the anastomosis nail is 3-6 mm, and the diameter of the end face of the anastomosis nail is 0.20-0.35 mm.

7. The preparation method of the degradable magnesium alloy in-situ composite anastomosis nail according to claim 5, characterized in that in the step (5), electrolytic fine polishing is adopted, a mixed solution of ethylene glycol ethyl ether, absolute ethyl alcohol and phosphoric acid in a volume ratio of 1:2:2 is adopted as a polishing solution, the polishing time is 1-10 min, the voltage is 10-20V, and the weight concentration of the phosphoric acid is 85%.

Technical Field

The invention relates to the technical field of biomedical materials, and particularly provides a degradable magnesium alloy in-situ composite anastomosis nail and a preparation method thereof.

Background

The existing titanium alloy nail is not degradable, belongs to foreign matters in a human body, and is easy to cause adverse reactions of inflammation, delayed healing, sensitization, carcinogenesis and the like of an organism after being left for a long time. When the implanted device is taken out after the tissue of the patient is repaired or healed, secondary operation is needed, and additional operation risk, economic pressure and physiological pain are brought to the patient.

The magnesium alloy is degradable, the medical clinical purpose that the magnesium alloy implant is gradually biodegraded in vivo until finally disappears is realized by utilizing the characteristic that magnesium is easy to corrode in the human body environment, compared with the traditional implanted metal, the magnesium alloy implant can avoid secondary taking-out operation, relieve the spirit and economic burden of a patient, but still has the problems of too fast degradation rate, poor mechanical strength and plasticity and the like.

The patent publication No. CN106086562B prepares the magnesium alloy anastomosis nail containing Zn, Mn, Sn, Ag and HA powder by an alloying method, and improves the corrosion resistance and the plasticity of the alloy to a certain extent; however, the preparation process is complex, the difficulty of directly extruding and forming the anastomosis nail is very high, and no related academic literature report exists at present. Patent grant publication No. CN 201617885U improves corrosion resistance, strength and hardness of the staple to a great extent by preparing ceramic, metal and oxide coatings on the surface of the staple, but the harder coating is easy to peel off in the process of deformation and anastomosis of the staple, which affects the use effect of the staple. The patent publication No. CN 105326535A adds a drug coating on the surface of the anastomosis nail, has biological functions of resisting bacterial infection, stopping bleeding, inhibiting vascular restenosis and the like, but does not fundamentally solve the problem that the mechanical property of the degradable nail is matched with the degradation rate.

Disclosure of Invention

The invention aims to provide a degradable magnesium alloy in-situ composite anastomosis nail and a preparation method thereof, and solves the problems of high degradation rate, low mechanical strength, poor plasticity and the like of the degradable magnesium alloy nail.

The technical scheme of the invention is as follows:

a degradable magnesium alloy in-situ composite anastomosis nailThe anastomosis nail is a composite structure material which is mainly divided into two parts, wherein the inside of the anastomosis nail is composed of Mg-Zn-Nd magnesium alloy with high strength and good plasticity, and the outside of the anastomosis nail is MgF with corrosion protection function₂Consists of Mg-Zn-Nd magnesium alloy anastomosis nail outer layer in-situ compounded MgF₂And (4) preparing the composition.

The degradable magnesium alloy in-situ composite anastomosis nail comprises the following chemical components in percentage by weight: zn0.2-3.0%, Nd0.2-2.3%, and Mg for the rest.

The technical indexes of the degradable magnesium alloy in-situ composite anastomosis nail are as follows according to the weight percentage: the tensile strength range is 260-320 MPa, the yield strength range is 170-240 MPa, and the elongation percentage range is 20-33%.

The degradable magnesium alloy in-situ composite anastomosis nail has MgF with corrosion protection effect on the outer layer₂The thickness is 1.0-3.3 μm.

The preparation method of the degradable magnesium alloy in-situ composite anastomosis nail comprises the following operation steps:

(1) smelting magnesium alloy from pure magnesium, Zn and Nd according to a proportion, casting the magnesium alloy into a magnesium alloy ingot, and carrying out homogenization heat treatment at the temperature of 300-450 ℃ for 3-7 h;

(2) removing surface defects and impurities from the magnesium alloy ingot in the step (1), extruding the magnesium alloy ingot into a bar with the diameter of 8-10 mm, wherein the extrusion ratio is 60-80: 1, and the extrusion temperature is 390-470 ℃;

(3) preparing the magnesium alloy bar in the step (2) into a wire with the diameter of 0.2-0.6 mm through cold drawing, and carrying out heat treatment annealing at the temperature of 280-330 ℃ for 30-120 min;

(4) preparing the magnesium alloy wire material in the step (3) into a U-shaped anastomosis nail;

(5) performing electrolytic polishing on the magnesium alloy anastomosis nail in the step (4), removing surface defects, and drying after ultrasonic cleaning;

(6) immersing the anastomosis nail in the step (5) into hydrofluoric acid for MgF₂In-situ compounding, wherein the weight concentration of hydrofluoric acid is 20-60%, the time is 3-200 h, and the treatment temperature is 20-35 ℃;

(7) and (4) ultrasonically cleaning the in-situ composite magnesium alloy anastomosis nail in the step (6), drying the anastomosis nail, and carrying out vacuum packaging.

In the step (4), the bent part of the U-shaped anastomosis nail is oval, the total length of the anastomosis nail is 10-15 mm, the height of the anastomosis nail is 3-6 mm, and the diameter of the end face of the anastomosis nail is 0.20-0.35 mm.

The preparation method of the degradable magnesium alloy in-situ composite anastomosis nail comprises the step (5) of adopting electrolytic fine polishing, wherein the polishing solution adopts a mixed solution of ethylene glycol ethyl ether, absolute ethyl alcohol and phosphoric acid in a volume ratio of 1:2:2, the polishing time is 1-10 min, the voltage is 10-20V, and the weight concentration of the phosphoric acid is 85%.

The design idea of the invention is as follows:

aiming at the problems that the titanium alloy anastomosis nail used at present is not degradable and is easy to cause infection and the like after being resided in a human body for a long time. According to the magnesium-based composite material anastomosis nail prepared by the invention, alloying elements Zn and Nd are adopted to improve the strength and plasticity of the alloy, and aiming at the problems that the degradation speed of the magnesium alloy anastomosis nail is too fast and the like, a chemical in-situ composite technology is adopted to compound magnesium fluoride and magnesium oxide materials at the outermost layer of the magnesium-based anastomosis nail, so that the corrosion resistance of the anastomosis nail is improved.

According to the magnesium-based composite material anastomosis nail, alloying elements are Zn and Nd, the Zn can form obvious solid solution and aging strengthening in Mg, the alloy strength is improved, the alloy column surface sliding direction can be effectively softened, and the plastic deformation capacity and the processing performance of the magnesium alloy are improved. Zn is an essential trace element in human body, participates in the metabolism of protein and enzymes, has close relationship with the operation of nervous system and the maintenance of immune organs, and has higher biological safety. The solid solubility of Nd in magnesium is 3.6%, the drawing performance and corrosion resistance of the magnesium alloy can be improved through solid solution heat treatment strengthening, and the strength and plasticity of the magnesium alloy are improved through grain refinement. Clinical research shows that a proper amount of rare earth elements can promote osteoblast proliferation, protect nervous system, resist coagulation, prevent arteriosclerosis, treat diabetes, resist cancer, diminish inflammation, relieve pain and the like. Only when the rare earth element is excessive, a certain adverse effect on the human body may be caused. In addition, fluorine introduced in-situ compounding is one of important trace elements in human bodies, and the fluorine element can stimulate osteoblast proliferation, promote mineral deposition on cancellous bone, promote iron absorption and growth of bones and teeth, improve nervous system excitability and play a good anti-aging role. The safe and proper fluorine intake amount disclosed by the Chinese academy of nutrition is 1.5-4.0 mg for adults.

The invention has the advantages and beneficial effects that:

1. aiming at the problems of high degradation rate, weak coating binding force, low mechanical strength, poor plasticity and the like of the conventional degradable magnesium alloy nail, the invention firstly adopts an alloying strategy to prepare a Mg-Zn-Nd alloy, improves the mechanical strength and the plasticity of the alloy through cold drawing and heat treatment processes, finally prepares the anastomosis nail, and then adopts an in-situ composite magnesium fluoride process to ensure that the designed anastomosis nail has better corrosion resistance and biological safety.

2. The anastomosis nail provided by the invention has good biological safety, mechanical property and plasticity and excellent corrosion resistance, can meet the use requirement of the anastomosis nail, can be degraded and disappear after reaching the use effect in a matrix, and is prevented from being taken out in a secondary operation.

3. The magnesium-based composite material can improve the mechanical property of the anastomosis nail, obtain better corrosion resistance and meet the use requirement of the medical degradable anastomosis nail.

Drawings

Fig. 1 is an SEM image of a magnesium-based composite material. In the figure, 2 layers are in-situ compounded MgF₂3 layers are magnesium alloy matrix and 1 layer is epoxy resin required for preparing samples.

Detailed Description

In the specific implementation process, the degradable anastomosis nail with good biological safety, mechanical property and plasticity and excellent corrosion resistance is prepared by alloying combined with drawing and in-situ compounding processes.

The following describes embodiments of the present invention in detail with reference to the drawings, which are implemented on the premise of the technical solution of the present invention, and give detailed implementation and specific operation procedures, but the scope of the present invention is not limited to the following embodiments.