A mussel shell biomimetic porous surface fracture internal fixation plate and a preparation method and anti-infection application thereof

Abstract

The present application belongs to the technical field of biological bionics, polymer, hydrogel material and the like, and particularly relates to a preparation method of a porous surface fracture internal fixation plate. The gentamicin-chitosan-acetic acid mixed solution is placed in an air compressor, the porous surface of the 3D printed fracture internal fixation plate is sprayed, after completion, the calcium chloride-collagen mixed solution is sprayed, then the fracture internal fixation plate is immersed in sodium hydroxide solution and sodium carbonate solution in sequence, and then freeze-drying is performed, so that the mussel shell bionic porous surface fracture internal fixation plate is obtained. The fracture internal fixation plate obtained by the present application has good biocompatibility, stable performance, mechanical properties close to natural bone and can realize drug loading for local prevention of fracture infection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biological simulation, high molecular polymer, hydrogel material and the like, and is a cross-field technology combination, and particularly relates to a porous surface fracture internal fixation plate and a preparation method and anti-infection application thereof. BACKGROUND

[0002] With the continuous increase of the population living alone and the continuous deepening of social pressure, people need more and more companionship and spiritual comfort in life, and pets have become an indispensable family member for many people.

[0003] At present, pet dogs and cats are mainly raised, and pet dogs and cats are naturally active and like to run and jump, and the risk of orthopedic diseases is particularly prominent, and fracture is a very disturbing problem. Fracture infection is a challenging complication caused by bacterial infection. Surgical treatment is often unavoidable, especially for chronic / delayed infections. Bacterial infection is a serious medical complication in orthopedic and trauma surgery worldwide. Staphylococcus aureus and Staphylococcus epidermidis are the most common pathogens in orthopedic infections. The infection rate of closed fractures is between 5% and 10%, and the infection rate of open fractures is even as high as 30%. These infections are difficult to treat because the sessile bacteria in the biofilm can escape the immune response and antibiotic treatment. Implant-related infections are mainly prevented by skin antiseptics and systemic antibiotic prophylaxis. Although the infection rate has decreased, systemic antibiotic prophylaxis cannot provide sufficient protection in the tissues around the medical device due to the limited concentration of antibiotics in the bone.

[0004] At present, the internal fixation of fracture is mainly made of metal materials such as steel plate, stainless steel plate and titanium alloy plate, which is favored due to its wide source, low price and high strength. However, the poor plasticity of the metal fixation plate in turn limits its application. At the same time, it is difficult for the metal fixation plate to realize drug loading, which may exist in the body rejection, and the radiation transmittance is poor, which will be affected by weather and other factors. In the treatment of fracture infection, the current general treatment and prevention are mainly systemic antibiotic treatment, and the use of antibiotics has a large dose, low bioavailability and strong toxicity. Therefore, there is a great need for an internal fixation plate with good biocompatibility, stable performance, mechanical properties close to natural bone and drug loading to locally prevent fracture infection to meet the needs of medical development.

[0005] Chinese patent (patent number: CN201711464175.8) discloses a long-chain carbon fiber PEEK outer wrapping thermoforming bone fixation plate and forming method, characterized by carbon fiber filament inner core and PEEK pre-impregnated layer wrapping into one and forming carbon fiber filament, weaving into carbon fiber cloth along the radial and weft direction, each layer of carbon fiber cloth is superimposed and sleeved in the inner groove of the mold, and the bone fixation plate is formed by pressing and heating. The bone fixation plate prepared by this method has complex preparation process, and the weaving direction of carbon fiber filament is difficult to accurately control. A mold needs to be made before preparation, which has high cost and is not suitable for personalized customization of fracture internal fixation plate due to its single nature. The PEEK composite material used is different from the pure PEEK used in the present invention, and the printing preparation method is completely different.

[0006] Chinese patent (patent number: CN2202222085934.2) discloses an antibacterial multi-layer composite medical rib fixation plate, characterized by an antibacterial film fixedly connected to one side of the main contact plate, the surface of the antibacterial film coated with silver ions, the other side fixedly connected with a whole stable plate, the inside of the whole stable plate provided with an isolation groove, the inner surface of the isolation groove connected with a heating plate, and the surface of the whole stable plate penetrated by a screw rod; the silver ions on the surface of the film penetrate the body from the outside to the inside to achieve antibacterial disinfection of the affected area. The mechanism of this method is different from the postoperative antibacterial and anti-inflammatory mechanism introduced in the present invention, and the application site is also different, which is not comparable.

[0007] Chinese patent (patent number: CN201710919239.2) discloses a manufacturing method of individualized 3D optimized internal fixation plate, characterized by using topological optimization method to design individualized internal fixation plate with 3D shape and optimized structure that meets the strength requirements under different occlusion modes and minimizes the volume, using metal stereoscopic printing SLM to perform stereoscopic printing on titanium alloy powder to obtain optimized structure internal fixation plate entity; compared with the present invention, the metal material used has radiation opacity, and the polyether ether ketone introduced in the present invention is radiation transparent and has no obvious influence on X-ray imaging; the application field of the metal powder used as base material is completely different from the present invention, and the stereoscopic printing SLM process used is also completely different from the present invention.

[0008] The Chinese patent (Patent No. CN201910276629.1) discloses a kind of to promote bone type polyether ether ketone cranial jaw internal fixation plate and preparation method, its characteristics are, by injection molding preparation polyether ether ketone cranial jaw internal fixation plate, the surface of internal fixation plate is sandblasted and then ultrasonic cleaning is carried out after treatment, then it is immersed in simulated body fluid, obtain the final to promote bone type polyether ether ketone cranial jaw internal fixation plate;First, the preparation method described in the application is simple, but it is obviously different from the preparation method described in the application;Second, the preparation cost is relatively high, and the plasticity is not strong;Finally, the sandblasting treatment of the surface of the internal fixation plate described in the application can cause certain rejection and infection risk in vivo application, and the gel drug-loaded modification of the surface of the internal fixation plate described in the application is non-toxic and harmless in vivo, and can play a role in anti-infection of the affected area, which is completely different from the application site and mechanism.

[0009] The Chinese patent (Patent No. CN202110692786.8) discloses a manufacturing method of composite material and structural functional metal bone implant, its characteristics are, the preparation process is to use layer-by-layer laser scanning melting and solidification method to print corresponding alloy powder for implant material design, and different porosity pore units are used for implant internal structure design;Compared with the application, the printing method of layer-by-layer laser scanning melting and solidification is slightly more expensive, the printing method of fused deposition modeling introduced in the application has less material loss and lower cost, and the printing preparation method is completely different;It mainly uses metal powder material as matrix to print into shape, has higher mechanical strength than natural bone, the polyether ether ketone fixation plate introduced in the application has good biocompatibility, radiation transmittance, and mechanical properties close to natural bone, and the mechanism and material application are different;It uses internal structure design with different porosities, pore diameter 0.4-1.0mm, and excessive pore diameter is not conducive to cell adhesion and growth, and the surface porous structure with pore diameter 0.3-0.5mm introduced in the application provides sufficient space for cell adhesion and growth, and promotes fracture healing.

[0010] The Chinese patent (Patent No. CN202310910827.5) discloses a film-coated drug release stent and its preparation method and application. Its characteristics are as follows: a bone repair stent is prepared by melt deposition molding, then the stent is soaked in a prepared polyvinyl alcohol-sodium alginate-ceftazidime mixed gel solution, then it is soaked in a calcium chloride solution for crosslinking, and finally a film-coated drug release stent is obtained by freeze-drying. First, the present invention introduces an air compression spraying method to make the drug distribution more uniform and the gel coating more regular, which is significantly different from the effect obtained by the soaking method. Second, the present invention introduces the addition of collagen to the calcium chloride solution as a biomimetic factor, which can promote wound healing and reduce the risk of infection to some extent. Finally, the present invention introduces the addition of sodium carbonate solution to make calcium ions react with carbonate ions to form calcium carbonate, realizing the biomimicry of biological mussel shells. Since calcium carbonate is one of the main components of bone, it can be used as a basic supplement for treatment and has a great impact on bone fracture rehabilitation. The realization mechanism and application purpose of the present invention are significantly different from the material theory and the present invention. SUMMARY

[0011] To solve the above problems, the present invention provides a preparation method for a mussel shell biomimetic porous surface bone fracture internal fixation plate. The obtained fixation plate has good biocompatibility, stable performance, mechanical properties close to natural bone, and can realize drug loading for local prevention of fracture infection.

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

[0013] A preparation method for a mussel shell biomimetic porous surface bone fracture internal fixation plate, comprising the following steps:

[0014] (1) Dissolve a certain amount of chitosan in acetic acid solution, disperse and dissolve thoroughly, to obtain a chitosan-acetic acid solution, so that the mass concentration of chitosan is 1-5%; the acetic acid solution is an acetic acid aqueous solution with a mass concentration of 1-5%; the molecular weight of chitosan is 5000-30000;

[0015] (2) Add a certain amount of gentamicin to the chitosan-acetic acid solution, disperse uniformly (stir thoroughly at 37℃, and then ultrasonic disperse for 10 min at 37℃), to obtain a gentamicin-chitosan-acetic acid mixed solution, so that the mass concentration of gentamicin is 0.1-0.3%;

[0016] (3) a certain amount of calcium chloride and collagen are mixed and dissolved in water (firstly stirred at room temperature, and then ultrasonically dispersed at 37 DEG C for 10 min) to obtain a calcium chloride-collagen mixed solution; the mass ratio of the calcium chloride, the collagen and water is (1-5):(0.1-0.3):(95-100);

[0017] (4) the 3D printing wire is printed into a porous surface fracture fixation plate according to a designed structure model by using a 3D printing device; the obtained fracture fixation plate is soaked in ethanol, ultrasonically treated (at 37 DEG C), and dried to obtain a porous surface fracture fixation plate;

[0018] The pore size of the porous surface of the fracture fixation plate is 0.4-0.6 mm, but is not limited to this; the material of the 3D printing wire is polyether ether ketone, and the wire diameter can be 1.65-1.85 mm, but is not limited to this; the pore size of the printing nozzle in the 3D printing device is 0.1-1.0 mm, but is not limited to this;

[0019] (5) the gentamicin-chitosan-acetic acid mixed solution is placed in an air compressor to spray the porous surface of the fracture fixation plate, after completion, the calcium chloride-collagen mixed solution is sprayed, and then the fracture fixation plate is soaked in a sodium hydroxide solution and a sodium carbonate solution, and then freeze-dried to obtain the mussel shell biomimetic porous surface fracture fixation plate.

[0020] The sodium hydroxide solution is an aqueous solution with a mass concentration of 1-3%; and the sodium carbonate solution is an aqueous solution with a mass concentration of 1-3%.

[0021] The mussel shell biomimetic porous surface fracture fixation plate can be applied in the fields of fracture fixation and anti-fracture infection.

[0022] The technical scheme of the present application has the following technical features:

[0023] (1) the present application uses chitosan as a carrier material of gel, and chitosan as a natural polymer has excellent biocompatibility, no toxicity, no irritation, natural degradation, good anticoagulant property, can promote cell growth, and is widely used in medical materials, and is used as a carrier of drugs, and has significant application advantages.

[0024] (2) The invention uses anhydrous calcium chloride and collagen as biomimetic factors of the mussel shell, which can be quickly cross-linked with chitosan acetic acid solution, and the molding is convenient and almost harmless to the human body, which promotes the formation of chitosan gel with nanostructure similar to pectin, and plays a wrapping and loading role on the added drugs, and the drug loading effect is better than that of the single soaking method. At the same time, calcium ions play an important role in the proliferation, differentiation and growth factor release of osteoblasts and other cells, and regulate osteogenesis by affecting the structure of local blood clots. In addition, the calcium ions in anhydrous calcium chloride react with carbonate ions in sodium carbonate to form calcium carbonate, which is one of the main components of bone and can be used as a basic supplement for treatment, which has a great impact on bone fracture recovery. An adult's body contains about 3 kg of collagen, mainly in the skin, bones, tendons, internal organs and other parts of the body. Its function is to maintain the shape and structure, and it is also an important raw material for repair and reconstruction. Collagen has good biocompatibility, biodegradability and bioactivity, and together with anhydrous calcium chloride as a biomimetic factor in the invention, it can help the recovery of the body to a certain extent.

[0025] (3) The invention uses sodium hydroxide solution and sodium carbonate solution to adjust the pH value from acidic to alkaline, which further promotes the reaction between the amino group in chitosan and the hydroxyl ion in sodium hydroxide to generate chitosan amine with very small solubility, forming a gel material that can protect the drug from being completely precipitated instantly after being immersed in the liquid, and lock the drug to reduce the rapid metabolism and absorption of the drug to achieve the effect of slow release. Adjusting to weak alkalinity can create a favorable environment for cell growth, normal body function and nutrient acquisition.

[0026] (4) The invention uses gentamicin as an anti-infective drug. Compared with other drugs, the advantage of gentamicin is its broad-spectrum antibacterial effect, which can effectively kill bacteria and prevent wound infection. It is also one of the few heat-stable drugs. Compared with the same type of anti-infective drugs such as penicillins and cephalosporins, its application environment is more extensive, and the restrictions are fewer, avoiding the loss of drug efficacy in some links of the pretreatment process.

[0027] (5) The porous surface internal fixation plate is manufactured by fused deposition modeling 3D printing; then the porous surface is sprayed by using an air compressor, and a gel is attached to the porous surface after spraying; and then a gel modified film is formed on the porous surface by freeze drying. Compared with the commonly used SLM metal powder printing, the porous surface internal fixation plate obtained by fused deposition modeling 3D printing has simple post-printing processing procedures, less material loss, lower printing cost, and provides sufficient space for cell adhesion and proliferation, and is more conducive to gel adhesion; a layer of gel film is constructed on the porous surface by spraying, which is conducive to the uniform dispersion of the gel and the drug on the porous surface, and is also conducive to the loading of the drug, and the local drug prevention by the internal fixation plate can provide a higher drug dose and bioavailability at the wound site, while having less toxicity, providing protection against postoperative infection, and providing a favorable internal environment for wound recovery, improving the cell affinity and adhesion of the surface of the fixation plate, etc.; and freeze drying plays a role in enhancing the stability and shaping of the gel, greatly preserving the original active substances. Therefore, the fused deposition modeling 3D printing porous surface internal fixation plate, the gel network structure porous surface modified by air compressor spraying gel, and the freeze-dried shaping in the present application have a complementary effect, and are an organic system, and the absence of one part or the replacement of one part by others will greatly affect the overall performance and application of the internal fixation plate.

[0028] (6) The fracture internal fixation plate is prepared by combining 3D printing technology, gel preparation technology, biological bionic technology and spraying technology, the shape and structure design of the internal fixation plate is almost not limited by any condition, the preparation process is relatively non-toxic and harmless or has very little toxicity, basically does not exist the situation of threatening the safety of the person, the material loss amount is less, the whole preparation process cost is lower, the material used is relatively green, environmentally friendly and non-polluting, and has good biocompatibility, the preparation process method is relatively simple and convenient, has good practicality and strong feasibility, and in vivo application can also play a good anti-infection effect, and has very beneficial significance for the method of fracture wound recovery and anti-fracture infection. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical scheme of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings described in the following are only part of the embodiments of the present application.

[0030] Figure 1 The preparation flowchart of the present application.

[0031] Figure 2 The E. coli and S. aureus inhibition experiments of the porous surface internal fixation plate of the present application and the comparative example.

[0032] Figure 3 Structure diagram of the porous surface fracture internal fixation plate designed in the present application.

[0033] Figure 4 Photo of the porous surface fracture internal fixation plate designed in the present application.

[0034] Figure 5 Scanning electron microscope image of the porous surface fracture internal fixation plate before spraying.

[0035] Figure 6 Scanning electron microscope image of the porous surface fracture internal fixation plate after spraying. Embodiment

[0036] All features disclosed in this specification, and / or all steps of any method or process so disclosed, can be combined in any combination, except combinations where at least some of the features and / or steps are mutually exclusive.

[0037] Any feature in the present specification, including any accompanying claims, abstract, as well as drawings, can be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. That is, unless expressly stated otherwise, every feature disclosed is one example only of a generic series of equivalent or similar features. In the following examples, the materials used are as follows, but the present application is not limited thereto:

[0038] Gentamicin-chitosan-acetic acid mixed solution: its preparation steps are as follows, (1) preparation of acetic acid solution: ice acetic acid is added to deionized water, and stirred at room temperature to obtain an acetic acid solution, wherein the mass ratio of ice acetic acid to deionized water is 2:98; (2) preparation of chitosan-acetic acid solution: chitosan is dissolved in the acetic acid solution, and stirred and dispersed at 60°C for 3h to fully dissolve, to obtain a chitosan-acetic acid solution, which is then moved to an ultrasonic treatment device for ultrasonic treatment for 10min, wherein the mass ratio of chitosan to acetic acid solution is 3:97; (3) preparation of gentamicin-chitosan-acetic acid mixed solution: gentamicin is added to the chitosan-acetic acid solution obtained in step 2) to make the concentration of gentamicin reach 2mg / ml, and the solution is stirred at 37°C, dispersed uniformly, and treated by ultrasonic dispersion at 37°C for 10min.

[0039] Calcium chloride-collagen mixed solution: its preparation steps are as follows, anhydrous calcium chloride and collagen are dissolved in deionized water, and stirred at room temperature, and treated by ultrasonic dispersion at 37°C for 10min to obtain a calcium chloride-collagen mixed solution, wherein the mass ratio of anhydrous calcium chloride, collagen and deionized water is 3:0.1:96.9.

[0040] Sodium hydroxide solution: its preparation steps are as follows, sodium hydroxide is dissolved in deionized water, and stirred at room temperature to dissolve, to obtain a sodium hydroxide solution, wherein the mass ratio of sodium hydroxide to deionized water is 1:99.

[0041] Sodium carbonate solution: The preparation steps are as follows: dissolve sodium carbonate in deionized water, stir thoroughly at room temperature to obtain sodium carbonate solution, wherein the mass ratio of sodium carbonate to deionized water is 3:97.

[0042] Preparation of 3D printing filament: Polyetheretherketone (PEEK) granules were placed in a vacuum drying oven at 120°C and vacuum dried for 12 hours. After removal, the material was heated, melted, and extruded using a micro twin-screw extruder. After cooling and collection, 3D printing filament was obtained. The twin-screw temperatures were set as follows: first stage 340-350°C, second stage 350-360°C, and third stage 360-365°C. The screw extrusion speed was 35 rpm.

[0043] Preparation of porous surface internal fixation plate: The 3D printed composite filaments prepared above are used to print the required fracture internal fixation plate according to the designed structural model using a 3D printing equipment; the obtained fixation plate is immersed in an appropriate amount of anhydrous ethanol, the temperature is set to 37℃, and ultrasonic treatment is performed in an ultrasonic treatment device for 5 minutes. After removal, it is placed in a vacuum drying oven at 120℃ for 3 hours to obtain a porous surface internal fixation plate.

[0044] Preparation of a biomimetic porous surface fracture internal fixation plate made from mussel shells: The dried fracture internal fixation plate was taken out of the vacuum drying oven and allowed to cool to room temperature. The previously prepared glycerol-gentamicin-chitosan acetic acid mixed solution was poured into the feeding chamber of an air compressor, and the pressure was set to 0.6 MPa. The porous surface of the fracture fixation plate was sprayed at a uniform speed. After completion, the same method was used to spray the plate with a calcium chloride-collagen mixed solution. The sprayed fixation plate was then immersed in a 1% sodium hydroxide solution for 5 minutes, removed, and then immersed in a 3% sodium carbonate solution for 5 minutes. Finally, it was placed in a freeze dryer and freeze-dried for 48 hours to obtain the biomimetic porous surface fracture internal fixation plate made from mussel shells.

[0045] Example 1: A 3D printing device is used to design and print a porous surface internal fixation plate for fracture according to a structural model; the obtained fixation plate is soaked in a proper amount of anhydrous ethanol, the temperature is set to 37°C, and the fixation plate is ultrasonically treated in an ultrasonic treatment device for 5 min, then taken out and placed in a 120°C vacuum drying oven for drying for 3 h, the dried internal fixation plate for fracture is taken out of the vacuum drying oven, and after it is cooled to room temperature, the gentamicin-chitosan acetic acid mixed solution prepared in the foregoing is poured into the feeding cavity of an air compressor, the pressure is set to 0.6 MPa, and the porous surface of the internal fixation plate for fracture is sprayed at a uniform speed, the spraying is cycled for 10 times, 5 s is waited after each spraying is completed before the next spraying is performed, after every 5 times of spraying, the calcium chloride-collagen mixed solution is sprayed for 2 times for crosslinking, the sprayed fixation plate is placed in a 40°C vacuum drying oven for drying for 10 min, then the fixation plate is taken out for the remaining times of spraying, after the spraying is completed, the calcium chloride-collagen mixed solution is finally sprayed for 2 times for crosslinking, the sprayed fixation plate is soaked in a 1% sodium hydroxide solution for 5 min, taken out, then soaked in a 3% sodium carbonate solution for 5 min, and finally placed in a freeze-drying machine for freeze-drying for 48 h, thereby obtaining a mussel shell biomimetic porous surface internal fixation plate for fracture.

[0046] Example 2: A 3D printing device is used to design and print a porous surface internal fixation plate for fracture according to a structural model; the obtained fixation plate is soaked in a proper amount of anhydrous ethanol, the temperature is set to 37°C, and the fixation plate is ultrasonically treated in an ultrasonic treatment device for 5 min, then taken out and placed in a 120°C vacuum drying oven for drying for 3 h, the dried internal fixation plate for fracture is taken out of the vacuum drying oven, and after it is cooled to room temperature, the gentamicin-chitosan acetic acid mixed solution prepared in the foregoing is poured into the feeding cavity of an air compressor, the pressure is set to 0.6 MPa, and the porous surface of the internal fixation plate for fracture is sprayed at a uniform speed, the spraying is cycled for 15 times, 5 s is waited after each spraying is completed before the next spraying is performed, after 5 times of spraying, the calcium chloride-collagen mixed solution is sprayed for 2 times for crosslinking, the sprayed fixation plate is placed in a 40°C vacuum drying oven for drying for 10 min, then the fixation plate is taken out for spraying, after 5 times of spraying, the calcium chloride-collagen mixed solution is sprayed for 2 times for crosslinking, the sprayed fixation plate is placed in a 40°C vacuum drying oven for drying for 10 min, then the fixation plate is taken out for the remaining times of spraying, after the spraying is completed, the calcium chloride-collagen mixed solution is finally sprayed for 2 times for crosslinking, the sprayed fixation plate is soaked in a 1% sodium hydroxide solution for 5 min, taken out, then soaked in a 3% sodium carbonate solution for 5 min, and finally placed in a freeze-drying machine for freeze-drying for 48 h, thereby obtaining a mussel shell biomimetic porous surface internal fixation plate for fracture.

[0047] Example 3: A 3D printing device is used to design and print a porous surface fracture internal fixation plate according to the structure model; the obtained fixation plate is soaked in a proper amount of anhydrous ethanol, the temperature is set to 37℃, and ultrasonic treatment is performed in an ultrasonic treatment device for 5 min, then the fixation plate is taken out and placed in a vacuum drying oven at 120℃ for drying for 3 h, the dried fracture internal fixation plate is taken out of the vacuum drying oven, and after the temperature is lowered to room temperature, the gentamicin-chitosan acetic acid mixed solution prepared in the previous step is poured into the feeding cavity of the air compressor, the pressure is set to 0.6 MPa, and the porous surface of the fracture internal fixation plate is sprayed at a constant speed, and the spraying is repeated for 20 times, after each spraying, the next spraying is performed after waiting for 5 s, the spraying is performed for 5 times, then the sprayed fixation plate is cross-linked by spraying with the calcium chloride-collagen mixed solution for 2 times, the sprayed fixation plate is placed in a vacuum drying oven at 40℃ for drying for 10 min, then the fixation plate is taken out and sprayed again, the spraying is performed for 5 times, then the sprayed fixation plate is cross-linked by spraying with the calcium chloride-collagen mixed solution for 2 times, the sprayed fixation plate is placed in a vacuum drying oven at 40℃ for drying for 10 min, then the fixation plate is taken out and sprayed again, the spraying is performed for 5 times, then the sprayed fixation plate is cross-linked by spraying with the calcium chloride-collagen mixed solution for 2 times, the sprayed fixation plate is placed in a vacuum drying oven at 40℃ for drying for 10 min, then the fixation plate is taken out and sprayed for the remaining times, after the spraying is completed, the fixation plate is cross-linked by spraying with the calcium chloride-collagen solution for 2 times, the sprayed fixation plate is soaked in a 1% sodium hydroxide solution for 5 min, then the fixation plate is taken out and soaked in a 3% sodium carbonate solution for 5 min, finally the fixation plate is placed in a freeze-drying machine and freeze-dried for 48 h, thereby obtaining a mussel shell biomimetic porous surface fracture internal fixation plate.

[0048] Example 4: A 3D printing device is used to design and print a porous surface fracture internal fixation plate according to the structure model; the obtained fixation plate is soaked in a proper amount of anhydrous ethanol, the temperature is set to 37℃, and ultrasonic treatment is performed in an ultrasonic treatment device for 5 min, then the fixation plate is taken out and placed in a vacuum drying oven at 120℃ for drying for 3 h, the dried fracture internal fixation plate is taken out of the vacuum drying oven, and after the temperature is lowered to room temperature, the gentamicin solution prepared in the previous step is poured into the feeding cavity of the air compressor, the pressure is set to 0.6 MPa, and the porous surface of the fracture internal fixation plate is sprayed at a constant speed, and the spraying is repeated for 20 times, after each spraying, the next spraying is performed after waiting for 5 s, the spraying is performed for 5 times, then the sprayed fixation plate is dried at room temperature for 10 min, then the fixation plate is sprayed again, the spraying is performed for 5 times, then the sprayed fixation plate is dried at room temperature for 10 min, then the fixation plate is sprayed again, the spraying is performed for 5 times, then the sprayed fixation plate is dried at room temperature for 10 min, then the fixation plate is sprayed for the remaining times, finally the fixation plate is placed in a freeze-drying machine and freeze-dried for 48 h, thereby obtaining a porous surface anti-infection fracture internal fixation plate.

[0049] Example 5 The 3D printing equipment is used to design and print the fracture porous surface internal fixation plate according to the structure model; the obtained fixation plate is soaked in a proper amount of anhydrous ethanol, the temperature is set to 37℃, ultrasonic treatment is performed in the ultrasonic treatment equipment for 5 min, the fixation plate is taken out and placed in a vacuum drying box at 120℃ for drying for 3h, the dried fracture internal fixation plate is taken out from the vacuum drying box, after the temperature is reduced to room temperature, the chitosan acetic acid solution prepared in the front is poured into the feeding cavity of the air compressor, the pressure is set to 0.6 MPa, the fracture internal fixation plate porous surface is uniformly sprayed, and the spraying is performed for 20 times, after each spraying is completed, the next spraying is performed after 5s, after spraying for 5 times, the calcium chloride-collagen mixed solution is sprayed for 2 times for crosslinking, the sprayed fixation plate is placed in a vacuum drying box at 40℃ for drying for 10 min, the fixation plate is taken out for spraying, after spraying for 5 times, the calcium chloride-collagen mixed solution is sprayed for 2 times for crosslinking, the sprayed fixation plate is placed in a vacuum drying box at 40℃ for drying for 10 min, the fixation plate is taken out for spraying, after spraying for 5 times, the calcium chloride-collagen mixed solution is sprayed for 2 times for crosslinking, the sprayed fixation plate is placed in a vacuum drying box at 40℃ for drying for 10 min, the fixation plate is taken out for the remaining number of times of spraying, after the spraying is completed, the calcium chloride-collagen solution is finally sprayed for 2 times for crosslinking, the sprayed fixation plate is soaked in a 1% sodium hydroxide solution for 5 min, taken out, soaked in a 3% sodium carbonate solution for 5 min, and finally placed in a freeze-drying machine for freeze-drying for 48h to obtain a mussel shell biomimetic porous surface fracture internal fixation plate.

[0050] Comparative Example 1 The 3D printing equipment is used to design and print the fracture porous surface internal fixation plate according to the structure model; the obtained fixation plate is soaked in a proper amount of anhydrous ethanol, the temperature is set to 37℃, ultrasonic treatment is performed in the ultrasonic treatment equipment for 5 min, the fixation plate is taken out and placed in a vacuum drying box at 120℃ for drying for 3h, and the porous surface internal fixation plate is obtained.

[0051] Performance evaluation: the evaluation results of the 3D printed porous surface internal fixation plate samples obtained in Examples 1-5 and Comparative Example 1 are shown in Table 1.

[0052] Table 1 Test results of porous surface internal fixation plate samples of examples and comparative examples

[0053]

[0054] Test results: According to the test results of the examples and the comparative examples, it can be seen that the materials of the examples and the comparative examples have no significant toxicity to cells; examples 1-4 have bacteriostatic effect on escherichia coli and staphylococcus aureus; from examples 1-3, it can be seen that with the increase of spraying times, the diameter of the bacteriostatic ring gradually increases, and the bacteriostatic effect on escherichia coli and staphylococcus aureus is more obvious; example 4 does not use gel loading and sprays gentamicin agent alone, and the bacteriostatic effect is weaker than examples 1-3; example 5 sprays chitosan acetic acid solution, and like comparative example 1, it does not show bacteriostatic effect; and the bending strength and bending modulus of examples 1-5 and comparative example 1 have no significant difference, the spraying times have no significant effect on the bending strength and bending modulus, and they are close to the mechanical properties of natural bone strength 2-180 MPa and natural bone modulus 0.01-3 GPa.

[0055] In the drawings Figure 1 The flow chart for preparing the anti-fracture infection porous surface internal fixation plate of the application, Figure 2 For the bacteriostatic experiment results of escherichia coli and staphylococcus aureus of examples 1-5 and comparative example 1 of the application, it can be seen that the bacteriostatic effect of example 1 on escherichia coli and staphylococcus aureus is not as significant as that of examples 2 and 3, the bacteriostatic intensity of example 3 is stronger than that of example 2, and the bacteriostatic effect is more significant, the bacteriostatic effect of example 4 is weaker than that of examples 1-3, the concentration of chitosan acetic acid solution of example 5 is not high, and it does not show bacteriostatic effect, and comparative example 1 has no bacteriostatic effect because it does not add any drug component. Figure 3 The design structure schematic diagram of the porous surface fracture internal fixation plate of the application, Figure 4 The photograph diagram of the porous surface fracture internal fixation plate of the application can be seen, which is composed of four fixed screw hole positions and a surface porous structure, Figure 5 The scanning electron microscope diagram of the porous surface of the porous surface fracture internal fixation plate of the application, Figure 6 The scanning electron microscope diagram of the porous surface of the porous surface fracture internal fixation plate of the application after spraying, Figure 5 Compared with

[0056] The above examples are part of the preferred embodiments of the application, but the embodiments of the application are not limited by the above examples, and any changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principles of the application shall be equivalent replacement modes, which are all included in the protection scope of the application.

Claims

1. A method for preparing a mussel shell biomimetic porous surface fracture fixation plate, characterized in that, It comprises the following steps: (1) a certain amount of chitosan is dissolved in acetic acid solution, dispersed and dissolved thoroughly to obtain a chitosan-acetic acid solution, so that the mass concentration of chitosan is 1-5%; (2) a certain amount of gentamicin is added to the chitosan-acetic acid solution and dispersed uniformly to obtain a gentamicin-chitosan-acetic acid mixed solution, so that the mass concentration of gentamicin is 0.1-0.3%; (3) a certain amount of calcium chloride and collagen are mixed and dissolved in water to obtain a calcium chloride-collagen mixed solution; (4) a 3D printing wire material is used to print a porous surface fracture fixation plate according to a designed structure model by using a 3D printing device; the obtained fracture fixation plate is soaked in ethanol, ultrasonically treated, and dried to obtain a porous surface fracture fixation plate; the material of the 3D printing wire material is polyether ether ketone; (5) the gentamicin-chitosan-acetic acid mixed solution is placed in an air compressor to spray the porous surface of the fracture fixation plate, after completion, the calcium chloride-collagen mixed solution is sprayed, and then the obtained product is immersed in sodium hydroxide solution and sodium carbonate solution, and then freeze-dried to obtain a mussel shell biomimetic porous surface fracture fixation plate.

2. The method of claim 1, wherein: In step (1), the acetic acid solution is an acetic acid aqueous solution with a mass concentration of 1-5%; the molecular weight of chitosan is 5000-30000.

3. The method of claim 1, wherein: In step (3), the mass ratio of calcium chloride, collagen and water is (1-5):(0.1-0.3):(95-100).

4. The method of claim 1, wherein: In step (4), the pore size of the porous surface of the fracture fixation plate is 0.4-0.6 mm; the wire diameter of the 3D printing wire material is 1.65-1.85 mm; and the pore size of the printing nozzle in the 3D printing device is 0.1-1.0 mm.

5. The method of claim 1, wherein: In step (5), the sodium hydroxide solution is an aqueous solution with a mass concentration of 1-3%; and the sodium carbonate solution is an aqueous solution with a mass concentration of 1-3%.

6. The mussel shell biomimetic porous surface fracture fixation plate obtained by the preparation method of any one of claims 1-5.

7. The use of the mussel shell biomimetic porous surface fracture fixation plate of claim 6 in the preparation of anti-fracture infection materials.

Images