Lantern frame internal fixation system with intelligent responsive coating and preparation method

Abstract

The application discloses a lampshade-imitating internal fixation system with an intelligent response coating and a preparation method, and belongs to the technical field of medical devices, and comprises the following steps: step one, cleaning and drying treatment of the obtained lampshade-imitating internal fixation system; step two, dissolving calcium acetate and glycerophosphate sodium in deionized water to obtain a micro-arc oxidation electrolyte, and electrolyzing the lampshade-imitating internal fixation system in step one; step three, constructing a middle antibacterial and anti-inflammatory drug depot layer on a bottom biocompatible bonding layer; and step four, uniformly coating the suspension on the lampshade-imitating internal fixation system with the middle antibacterial and anti-inflammatory drug depot layer by using a dipping-drawing method. The application realizes precise and efficient intelligent antibacterial and anti-inflammatory, reduces the risk of postoperative complications, and provides a stable local biological environment for fracture healing.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of medical devices, and particularly relates to a lampshade-imitating frame internal fixation system with an intelligent responsive coating and a preparation method. BACKGROUND

[0002] Fracture of extremities is one of the most common diseases in orthopedics, and the core of its treatment is to achieve stable internal fixation to provide a good mechanical environment for bone healing. Traditional fracture internal fixation technology mainly relies on the nail-plate system, that is, a steel plate is covered on the surface of the bone and fixed by screws, which has been widely used in clinical practice. However, a large number of clinical practices show that the traditional nail-plate internal fixation system has several inherent technical defects, which seriously affect the treatment effect of patients.

[0003] After the steel plate internal fixation is implanted as a foreign body in the body, it provides a suitable environment for bacterial adhesion and biofilm formation; once infection occurs, it usually needs to be removed urgently to contain the spread of infection, which not only brings severe physiological pain to the patient, but also causes heavy economic burden. In addition, the traditional internal fixation steel plate has obvious functional limitations — it can only provide basic mechanical support for fracture healing, and cannot actively release active ions to promote bone growth, making it difficult to further accelerate the fracture healing process. Further speaking, for the internal fixation that needs to be removed by secondary surgery, the traditional steel plate also faces the key problem of difficult removal: after long-term implantation, the bone tissue is easy to over-cover the surface of the steel plate or grow into the screw hole, thereby causing the bone-implant interface to be too tightly combined; this phenomenon not only increases the operation complexity and significantly increases the time of the removal surgery, but also may cause additional bone loss and damage to the surrounding soft tissue, increasing the postoperative recovery burden of the patient.

[0004] In order to overcome the above problems, some improved schemes have appeared in the prior art, such as adding an antibacterial coating (such as a silver coating) or a coating that promotes bone integration (such as a hydroxyapatite coating) on the surface of the implant. However, these coatings have single functions and cannot simultaneously cope with the challenges of early postoperative infection, poor fracture healing, and late bone overgrowth. In particular, a simple antibacterial coating cannot control aseptic inflammation, and it will exacerbate the difficulty of removal, and these schemes have not achieved time-dependent and intelligent functional management.

[0005] Therefore, there is an urgent need in the art for a new internal fixation system that can not only provide stable, multi-planar mechanical fixation, but also intelligently and efficiently resist infection and inflammation in the early implantation stage through advanced surface technology, and release bone active substances to promote fracture healing, and is safe and minimally invasive for removal in the later healing stage, thereby achieving optimal management of the entire cycle of fracture treatment. SUMMARY

[0006] The present application aims at the problems and deficiencies described in the background art, and provides a lampshade-imitating internal fixation system with intelligent responsive coating and a preparation method.

[0007] The preparation method of the lampshade-imitating internal fixation system with intelligent responsive coating comprises the following steps:

[0008] Step one: cleaning and drying treatment of the obtained lampshade-imitating internal fixation system;

[0009] Step two: dissolving calcium acetate and glycerophosphate sodium in deionized water to obtain a micro-arc oxidation electrolyte, taking the pretreated lampshade-imitating internal fixation system in step one as an anode and a stainless steel plate as a cathode, immersing them in the micro-arc oxidation electrolyte for treatment, and then taking out the lampshade-imitating internal fixation system, cleaning and drying it;

[0010] Step three: dissolving chitosan in an acetic acid solution with a pH of 5.5 to obtain a mixed solution A, dispersing silver nanoparticles and ε-polylysine in a sodium alginate solution and magnetically stirring to obtain a mixed solution B, preparing liposomes loaded with dexamethasone, mixing the liposomes with the mixed solution B to obtain a mixed solution C, immersing the lampshade-imitating internal fixation system treated by micro-arc oxidation in step two in the mixed solution A first, then rinsing it with deionized water and blowing it dry with nitrogen, then immersing it in the mixed solution C, rinsing it again and blowing it dry with nitrogen, and constructing a middle layer of an antibacterial and anti-inflammatory drug depot layer on the bottom layer of a biocompatible bonding layer;

[0011] Step four: dissolving polycaprolactone particles in dichloromethane to obtain a mixed solution D, adding bioactive glass nanoparticles to the mixed solution D, ultrasonic dispersing to form a uniform suspension, uniformly coating the suspension on the lampshade-imitating internal fixation system with the middle layer of the antibacterial and anti-inflammatory drug depot layer obtained in step three by using the immersion-drawing method, then placing it in a fume hood to let the solvent evaporate naturally, and then transferring it to a vacuum drying oven to form a top layer of a healing-promoting and lubricating separation layer.

[0012] Preferably, the set parameters for immersing in the micro-arc oxidation electrolyte in step two are as follows: the temperature of the micro-arc oxidation electrolyte is 20-30°C, a bipolar pulse power source is used, the voltage is 350V, the frequency is 500Hz, the duty cycle is 20%, and the treatment time is 5 minutes.

[0013] Preferably, the specific process for preparing the dexamethasone-loaded liposome is as follows: 75 mol% of dipalmitoyl phosphatidylcholine, 20 mol% of distearoyl phosphatidylcholine, 5 mol% of cholesterol and dexamethasone are weighed, the mass ratio of dexamethasone to total lipids is 1:10-1:15, and they are placed in a dry round-bottom flask; a chloroform / methanol mixed solvent is added to the round-bottom flask; the round-bottom flask is installed on a rotary evaporator; the water bath temperature is set to 45°C; rotation is started and vacuum is applied; under the conditions of rotation and reduced pressure, the organic solvent is rapidly evaporated, and a thin and uniform lipid-drug composite film is formed on the inner side of the bottle wall; the rotary evaporator and vacuum are turned off; nitrogen or argon is slowly introduced into the round-bottom flask; the round-bottom flask is removed; preheated to 55°C water medium phosphate buffer is immediately added to the round-bottom flask to make the lipid-drug concentration 10-20 mg / mL; the round-bottom flask is reinstalled on the rotary evaporator; under the condition of 55°C water bath, no vacuum is applied; rotation is performed for 45-60 minutes to form a multilayer large liposome containing dexamethasone.

[0014] Preferably, the obtained multilayer large liposome suspension is subjected to intermittent ultrasonic treatment using an ultrasonic cell crusher under ice water bath conditions; the ultrasonic treated suspension is repeatedly subjected to extrusion filtration through a polycarbonate membrane; and dialysis is used to remove free dexamethasone; and the monodisperse liposome suspension after dialysis purification is filtered through a 0.22 μm sterile filter to remove bacteria.

[0015] Preferably, in step three, the phase transition temperature of dipalmitoyl phosphatidylcholine in the middle antibacterial and anti-inflammatory drug reservoir layer is 41°C.

[0016] The lantern frame internal fixation system with the intelligent responsive coating is prepared by the preparation method of the lantern frame internal fixation system with the intelligent responsive coating.

[0017] The present application has the following beneficial effects:

[0018] The present application realizes precise and efficient intelligent antibacterial and anti-inflammatory, greatly reduces the risk of postoperative complications, and the fine coating design can intelligently respond to the microenvironment changes of pH decrease in the infection area and temperature rise in the inflammation area, realizing the "on-demand" release of antibacterial drugs (AgNPs and ε-PL) and anti-inflammatory drugs (dexamethasone). This targeted release strategy not only can efficiently intervene at the first time of infection and inflammation, overcoming the shortcomings of traditional coating drug blind and continuous release, but also improves the drug utilization efficiency and reduces the risk of systemic side effects, thereby providing a safer and more stable local biological environment for fracture healing.

[0019] The application breaks the clinical contradiction between "firm fixation" and "easy to take out", significantly optimizes the secondary operation experience, and through the design of a unique "healing promotion and lubrication separation layer", the outermost coating in the application can protect the inner layer drug as a barrier in the early stage of implantation, and moderately delays the excessive growth of the tissue; in the middle and late stages of bone healing, the hydrophobicity and smooth surface of the layer can effectively reduce tissue adhesion, and in the secondary removal operation, the layer can serve as a prefabricated separation interface, significantly reducing the torque and resistance in the removal process, making the removal operation more simple and fast, effectively shortening the operation time, and reducing the secondary trauma of the patient and the operation burden of the doctor.

[0020] The application provides full-cycle bone healing promotion function, accelerates the rehabilitation process, and the bioactive glass (BAG) nanoparticles in the outermost layer of the coating can continuously and slowly release calcium, silicon and other osteogenic active ions, continuously stimulate osteoblast activity during the entire implantation period, promote bone matrix mineralization and new bone formation, and the design of combining antibacterial and anti-inflammatory with active osteogenesis provides all-round support for bone healing, which is expected to further shorten the healing period.

[0021] The application has a multifunctional synergistic effect, and the overall performance is better than that of a single functional coating.

[0022] Single superposition, the three-layer composite coating structure of the application constitutes an organic whole, the bottom layer of biocompatible bonding layer ensures the firm combination of the coating and the substrate; the middle layer of antibacterial and anti-inflammatory drug reservoir layer realizes rapid response to pathological signals; and the top layer of healing promotion and lubrication separation layer takes into account long-term bioactivity and ultimate removability, these functions are sequentially developed in the time axis and synergistically act in space, producing a "1+1>2" technical effect, solving the technical problem of "trade-off" of a single functional coating. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a structure schematic diagram of the lantern frame internal fixation system in the application.

[0024] Figure 2 It is a preparation schematic diagram of the intelligent responsive coating of the lantern frame internal fixation system in the application.

[0025] Figure 3 It is a partial enlarged principle diagram of the three-layer coating of the lantern frame internal fixation system in the application.

[0026] Figure 4 It is an implantation effect diagram of a plurality of lantern frame internal fixation systems.

[0027] In the figure: 1: point structure; 2: line structure; 3: threaded hole; 4: circular arc transition zone; 5: bottom layer of biocompatible bonding layer; 6: middle layer of antibacterial and anti-inflammatory drug reservoir layer; 7: top layer of healing promotion and lubrication separation layer. DETAILED DESCRIPTION

[0028] In order to better illustrate the preparation process involved in the present application and the advantages over the prior art, further explanation will be made according to the accompanying drawings.

[0029] According to the accompanying drawings, a preparation method of a lantern-imitating frame internal fixation system with an intelligent responsive coating comprises the following steps:

[0030] Step one: Pretreatment of the lantern-imitating frame internal fixation system: a precision CNC machine is used to process the required lantern-imitating frame internal fixation system, and then the lantern-imitating frame internal fixation system is mechanically polished to remove surface burrs and sharp edges, ensuring the surface of the lantern-imitating frame internal fixation system to be smooth and avoiding stress concentration. Then the lantern-imitating frame internal fixation system is sequentially placed in acetone, anhydrous ethanol and deionized water for ultrasonic cleaning for 15 minutes each, to completely remove surface grease and contaminants. After cleaning, it is placed in a 60°C oven for drying for standby use;

[0031] Step two: Preparation of the bottom biocompatible bonding layer 5 (micro-arc oxidation): 0.15 mol / L calcium acetate and 0.06 mol / L glycerol sodium phosphate are dissolved in deionized water to obtain a micro-arc oxidation electrolyte, which is stirred uniformly. The pretreated lantern-imitating frame internal fixation system in step one is used as the anode, and a stainless steel plate is used as the cathode, which are immersed in the micro-arc oxidation electrolyte. The temperature of the micro-arc oxidation electrolyte is controlled at 20-30°C. A bipolar pulse power source is used, with the following parameters set: voltage 350V, frequency 500Hz, duty cycle 20%, and treatment time 5 minutes. After treatment, the lantern-imitating frame internal fixation system is taken out, rinsed with a large amount of deionized water to remove the residual micro-arc oxidation electrolyte on the surface, and then dried in an 80°C oven;

[0032] Step three: preparation of middle antibacterial and anti-inflammatory drug reservoir layer 6 (layer-by-layer self-assembly): 0.5 mg / mL of chitosan was dissolved in acetic acid solution with pH of 5.5 to obtain mixture A, 1 mg / mL of silver nanoparticles (AgNPs) and 1 mg / mL of ε-polylysine (ε-PL) were directly dispersed in sodium alginate solution and magnetically stirred for 2 hours to obtain mixture B; liposomes loaded with dexamethasone were prepared by thin film hydration method; the liposomes were mixed with mixture B to obtain mixture C; the micro-arc oxidation treated imitation lantern frame internal fixation system obtained in step two was first immersed in the above positively charged mixture A for 10 minutes to adsorb a layer of polyelectrolyte, then rinsed with deionized water and dried with nitrogen, then immersed in the negatively charged mixture C for 10 minutes to adsorb a layer of polyelectrolyte with opposite charge, rinsed again and dried with nitrogen; the above process of adsorbing polyelectrolyte was repeated for 15-20 cycles, and finally a middle antibacterial and anti-inflammatory drug reservoir layer 6 with 15-20 bilayers was constructed on the bottom biocompatible bonding layer 5;

[0033] Step four: preparation of top healing and lubrication separation layer 7 (dip-coating method): polycaprolactone (PCL) particles were dissolved in dichloromethane to prepare a mixture D with a concentration of 5 wt%, then 30% of bioactive glass (BAG, composition: 55% SiO2, 41% CaO, 4% P2O5) nanoparticles based on the total solid mass were added to the mixture D, ultrasonic dispersion was performed for 2 hours to form a uniform suspension, the suspension was uniformly coated on the imitation lantern frame internal fixation system with the middle antibacterial and anti-inflammatory drug reservoir layer 6 obtained in step three by dip-coating method, the pulling speed was controlled at 100 mm / min, then the system was placed in a fume hood for natural solvent evaporation for 30 minutes, and then transferred to a vacuum drying oven at 40°C for drying for 24 hours to form a dense and smooth top healing and lubrication separation layer 7.

[0034] Preferably, in step three, the specific process of preparing dexamethasone-loaded liposomes by thin film evaporation-hydration method is as follows: dexamethasone is an anti-inflammatory drug known in the prior art, 75 mol% of DPPC (dipalmitoyl phosphatidylcholine), 20 mol% of DSPC (distearoyl phosphatidylcholine), 5 mol% of cholesterol and dexamethasone (the mass ratio of drug to total lipid is 1:10-1:15) are accurately weighed and placed in a dry round-bottom flask, an appropriate amount of chloroform / methanol mixed solvent (about 20-30 mL, volume ratio 2:1) is added to the round-bottom flask, and the round-bottom flask is firmly installed on a rotary evaporator, the rotary evaporator is started, the water bath temperature is set to 45°C (which is higher than the phase transition temperature of all lipids to ensure that the lipids are in a liquid crystal state), and the rotation is started (about 60-100 rpm) and slowly vacuumed. Under the conditions of rotation and reduced pressure, the organic solvent is rapidly evaporated, and a thin and uniform lipid-drug composite film is formed on the inner side of the bottle wall. Continue evaporation for 30-45 minutes until there is no flowing liquid on the bottle wall and the film appears uniform. Further close the rotary evaporator and vacuum, slowly introduce nitrogen or argon into the round-bottom flask to break the vacuum, remove the round-bottom flask, and immediately add a preheated to 55°C (must be higher than the highest phase transition temperature of the liposomes) hydration medium phosphate buffer (PBS, pH 7.4) to the round-bottom flask to make the lipid-drug concentration 10-20 mg / mL. Further re-install the round-bottom flask to the rotary evaporator in the 55°C water bath, without vacuum, and rotate at a lower speed (about 50 rpm) for 45-60 minutes. During this process, the lipid film will be hydrated and detached from the bottle wall, and spontaneously curl to form multilayer large liposomes containing dexamethasone; the obtained multilayer large liposomes suspension is subjected to intermittent ultrasonic treatment (e.g. ultrasonic treatment for 3 seconds, intermittent treatment for 5 seconds) using an ultrasonic cell crusher under ice water bath conditions for a total time of 2-3 minutes to obtain liposomes with smaller particle size. To further obtain monodisperse liposomes, the ultrasonic treated suspension is repeatedly extruded through a polycarbonate membrane, usually through filter membranes with pore sizes of 0.8 μm, 0.4 μm and 0.2 μm in turn, and extruded 10-15 times. Since dexamethasone is a hydrophobic drug, it is mainly encapsulated in the lipid bilayer, but a small amount of unencapsulated drug crystals still exist. Dialysis method (dialysis in PBS at 4°C for 24 hours, with 3-4 times of dialysis liquid change during the period) is used to remove free drugs. The dialysis purified monodisperse liposome suspension is filtered through a 0.22 μm sterile filter for sterilization, and then stored in a 4°C refrigerator in the dark after being divided into small portions.

[0035] The working principle of the present application is as follows:

[0036] In step one, the imitation lantern frame internal fixation system is a "multi-point linear" structure, including point structure 1 and line structure 2, the point structure 1 is fixedly connected with the line structure 2, the point structure 1 is a medical Ti6Al4V alloy ring, and the inner wall is a threaded hole 3; the line structure 2 is a rod-shaped medical Ti6Al4V alloy rod, and the outer side of the point structure 1 edge is provided with a circular arc transition area 4, and the structure is prior art which will not be described in detail.

[0037] In step two, a porous and rough calcium titanate / calcium phosphate ceramic layer is in-situ grown on the surface of the imitation lantern frame internal fixation system through high-voltage discharge, the calcium titanate / calcium phosphate ceramic layer is metallurgically combined with the titanium base (imitation lantern frame internal fixation system), and the binding force is extremely strong, and the micron-level porous structure provides a large specific surface area and mechanical interlocking site for the attachment of the subsequent coating.

[0038] In step three, the phase transition temperature (Tm) of dipalmitoyl phosphatidylcholine (DPPC) in the middle layer antibacterial and anti-inflammatory drug reservoir layer 6 is about 41°C, which is the core of the temperature-sensitive behavior, and distearoyl phosphatidylcholine (DSPC) is an auxiliary component, which improves the stability and rigidity of the lipid bilayer, and cholesterol is used to adjust the fluidity, stability and encapsulation efficiency of the lipid membrane.

[0039] In step three, the middle layer antibacterial and anti-inflammatory drug reservoir layer 6 is constructed into a thin film with a structure that is precisely controllable through electrostatic adsorption of positive and negative charges, the pH-responsive chitosan / sodium alginate system will be protonated or charge neutralized under the acidic environment caused by infection, causing the film to swell and dissociate, thereby releasing AgNPs and ε-PL in an explosive manner, while dexamethasone wrapped in liposomes will be released under the trigger of local high temperature (~39°C) caused by surgical trauma or inflammation, achieving precise anti-inflammatory.

[0040] In step four, polycaprolactone (PCL) is a polymer with slow degradation, good biocompatibility and hydrophobicity, which serves as a physical barrier to protect the inner layer of drugs and reduce tissue adhesion, and the doped bioactive glass (BAG) nanoparticles slowly dissolve in body fluids to release Ca²⁺, SiO4 4 ions, continuously stimulating osteoblast proliferation and differentiation, promoting bone healing, and when the second surgery is performed, the hydrophobic and smooth polycaprolactone (PCL) layer becomes an ideal lubricating separation interface, increasing the removability of the second surgery.

[0041] The response principle of the mixed solution A (pH response system) is as follows: under normal physiological conditions (pH is 7.4), through the method of layer-by-layer self-assembly in step three, the electrostatic attraction between the positively charged chitosan and the negatively charged sodium alginate is strong, the film structure is stable and dense, like a "locked warehouse", which safely locks the drug inside and only "leaks" at an extremely slow speed. Under the infection / acidic environment (pH is 5.5-6.5), the concentration of H + (the hydrogen ion) in the environment increases, the H + in the environment will competitively combine with the -COO⁻ on the sodium alginate chain, so that it is converted into electrically neutral -COOH, which is equivalent to removing the "electrostatic rivet" connecting the chitosan (CS) and sodium alginate (SA) molecules, the most critical cross-linking force between CS-SA is greatly weakened, which will force the originally tightly combined polyelectrolyte film structure to swell, become loose, and eventually collapse.

[0042] The response principle of the mixed solution C (temperature-sensitive response system) is as follows: liposomes are microspheres composed of phospholipid bilayers. The phospholipid molecules are arranged in an orderly and compact manner at low temperatures, like "gel" (solid state), and have poor permeability; when the temperature rises to a certain critical point, they become disordered and loose, like "liquid crystal" (liquid state), and the permeability increases sharply, and this critical temperature is called "phase transition temperature". The present application specially selects dipalmitoyl phosphatidylcholine (DPPC) as the main phospholipid, and the phase transition temperature (Tm) of the pure phase is about 41°C. By mixing with other phospholipids (such as DSPC, Tm ~ 55°C) and cholesterol in a precise ratio, the phase transition temperature of the final liposome mixture is adjusted and widened to a suitable range of 38°C-41°C. At normal body temperature (37°C), the temperature is lower than the phase transition temperature, and the lipid bilayer is in a dense "gel" state, like a solid wall, which tightly locks the dexamethasone inside, and almost no leakage occurs. When the local temperature of inflammation rises (~ 39°C), the temperature has entered the phase transition temperature window we designed, at this time, the "tails" of the phospholipid molecules in the lipid bilayer begin to melt, the arrangement changes from ordered to disordered, the structure becomes loose and unstable, and a large number of temporary "holes" or "defects" appear, and the dexamethasone wrapped inside the liposome can now freely diffuse out through these holes. The closer the temperature is to or exceeds the phase transition midpoint, the faster the release speed.

[0043] The clinical use method comprises:

[0044] According to the patient's imaging data, select the appropriate size of the imitation lantern frame internal fixation system. Anesthetize the patient, reduce the fracture by closed or limited incision, make a small incision at both ends of the fracture, implant the imitation lantern frame internal fixation system percutaneously, cross the fracture line, implant locking screws through the threaded holes 3 of the point structure 2, and firmly fix the imitation lantern frame internal fixation system at both ends of the fracture. The imitation lantern frame internal fixation system starts working in the body. If early signs of infection (such as local redness, heat and pain) appear after surgery, the acidic microenvironment and high heat will immediately trigger the intelligent release of the middle antibacterial and anti-inflammatory drug storage layer 6, and precise treatment will be performed; during the fracture healing period, the doped bioactive glass (BAG) nanoparticles slowly dissolve in the body fluid, releasing Ca²⁺, SiO4 4 ⁻plasma, continuously stimulating osteoblast proliferation and differentiation, promoting bone healing; take out the operation (about 1 year after surgery): make the original incision, expose the point structure 2, due to the effect of the top healing and lubricating separation layer 7, the bone tissue and the implant interface have moderate bonding force. Using special instruments to connect the screws, the system can be completely rotated out with significantly lower extraction torque than traditional steel plates, with small surgical trauma and short operation time.

[0045] The pH-responsive system is the "door of the big warehouse" responsible for quickly responding to infection (acid) and releasing antibacterial ammunition, and the temperature-sensitive response system is the "lock of the intelligent safe in the warehouse" responsible for accurately responding to inflammation (heat) and releasing anti-inflammatory ammunition. They do not interfere with each other, and an acidic environment will not cause liposomes to release dexamethasone (unless accompanied by an increase in inflammation); and a simple heating (such as mild fever) will not cause the explosive release of AgNPs and ε-PL.

Claims

1. A method for preparing a lantern-like frame internal fixation system with an intelligent responsive coating, characterized in that: The method comprises the following steps: Step 1: cleaning and drying the obtained imitation lantern frame internal fixation system; Step 2: dissolving calcium acetate and glycerophosphate sodium in deionized water to obtain a micro-arc oxidation electrolyte, using the pretreated imitation lantern frame internal fixation system in step 1 as an anode and a stainless steel plate as a cathode, and immersing them in the micro-arc oxidation electrolyte for treatment, and then taking out the imitation lantern frame internal fixation system, cleaning and drying it; Step 3: dissolving chitosan in an acetic acid solution with a pH of 5.5 to obtain a mixed solution A, dispersing silver nanoparticles and ε-polylysine in a sodium alginate solution and magnetically stirring to obtain a mixed solution B, preparing liposomes loaded with dexamethasone, and mixing the liposomes with the mixed solution B to obtain a mixed solution C, immersing the imitation lantern frame internal fixation system treated by micro-arc oxidation in the mixed solution A, rinsing with deionized water and blowing dry with nitrogen, then immersing it in the mixed solution C, rinsing again and blowing dry with nitrogen, and constructing a middle layer of an antibacterial and anti-inflammatory drug reservoir layer on the bottom layer of a biocompatible bonding layer; Step 4: dissolving polycaprolactone particles in dichloromethane to obtain a mixed solution D, adding bioactive glass nanoparticles to the mixed solution D, ultrasonic dispersion to form a uniform suspension, uniformly coating the suspension on the imitation lantern frame internal fixation system with the middle layer of the antibacterial and anti-inflammatory drug reservoir layer obtained in step 3 by using the immersion-drawing method, then placing it in a fume hood to allow the solvent to evaporate naturally, and then transferring it to a vacuum drying oven to form a top layer of a healing-promoting and lubricating separation layer.

2. The method of claim 1, wherein the method further comprises: The set parameters for the treatment in the micro-arc oxidation electrolyte in step 2 are as follows: the temperature of the micro-arc oxidation electrolyte is 20-30°C, a bipolar pulse power source is used, the voltage is 350V, the frequency is 500Hz, the duty cycle is 20%, and the treatment time is 5 minutes.

3. The method of claim 1, wherein the method further comprises: The specific process for preparing the liposomes loaded with dexamethasone is as follows: weighing 75mol% of dipalmitoyl phosphatidylcholine, 20mol% of distearoyl phosphatidylcholine, 5mol% of cholesterol and dexamethasone, with the mass ratio of dexamethasone to total lipids being 1:10-1:15, placing them in a dry round-bottom flask, adding a chloroform / methanol mixed solvent to the round-bottom flask, installing the round-bottom flask on a rotary evaporator, setting the temperature of the water bath to 45°C, starting rotation and vacuumizing, rapidly evaporating the organic solvent under the conditions of rotation and reduced pressure, and forming a thin and uniform lipid-drug composite film on the inner side of the bottle wall, closing the rotary evaporator and vacuum, slowly introducing nitrogen or argon into the round-bottom flask, taking out the round-bottom flask, immediately adding a preheated to 55°C hydration medium phosphate buffer to the round-bottom flask to make the lipid-drug concentration 10-20mg / mL, re-installing the round-bottom flask on the rotary evaporator, rotating for 45-60 minutes in a 55°C water bath without vacuumizing, and forming multilayer large liposomes containing dexamethasone.

4. The method of claim 3, wherein the method further comprises: The obtained multi-layer large liposome suspension is intermittently ultrasonated using an ultrasonic cell pulverizer under ice water bath conditions, the suspension after ultrasonation is repeatedly extruded and filtered through a polycarbonate membrane, and free dexamethasone is removed using a dialysis method, and the monodisperse liposome suspension after dialysis purification is filtered and sterilized through a 0.22 μm sterile filter.

5. The method of claim 4, wherein the method further comprises: In step three, the phase transition temperature of dipalmitoyl phosphatidylcholine in the antibacterial and anti-inflammatory drug depot layer is 41°C.

6. A lantern-style internal fixation system with a smart responsive coating, characterized in that: The preparation method of the imitation lantern frame internal fixation system with intelligent responsiveness coating according to any one of claims 1 to 5.

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