Microwave response drug controlled release bone cement as well as preparation method and application thereof

Abstract

The invention discloses microwave response drug controlled release bone cement and a preparation method and application thereof.The bone cement is obtained by mixing solid-phase bone repair powder containing a microwave response drug-loaded nano container with a liquid phase, the solid-phase powder comprises, by mass, 25-40 parts of dead-burned magnesium oxide powder, 15-25 parts of phosphate powder and 0.05-0.9 part of a microwave response drug nano carrier, and the liquid phase is prepared from, by mass, 25-40 parts of dead-burned magnesium oxide powder, 15-25 parts of phosphate powder and 0.05-0.9 part of a microwave response drug nano carrier; and the liquid phase comprises the following components in parts by mass: 50-80 parts of ultrapure water and 0.3-2.0 parts of an acidic retarder. A CNT-PPy core-shell precursor is prepared through an in-situ oxidation polymerization method, and after plasma gradient doping treatment and amino silane coupling agent interface bridging, liquid nitrogen freezing pore forming is carried out to prepare the CNT-PPy composite material. Under 3W low-power microwave irradiation for 24 hours, the accumulative release rate can reach 82%, the temperature rise range is safe, the compression strength is excellent, the cell survival rate exceeds 92%, mechanical stability and precise drug release are both considered, and the bone defect repairing and local drug treatment are suitable.

Description

Technical Field

[0001] The present invention relates to an injectable bone cement for drug controlled release based on the principle of microwave response, its preparation method and application, belonging to the technical fields of biomedical materials and tissue engineering. Background Art

[0002] Currently, traditional bone cements used for bone defect repair generally have deficiencies such as fast curing, intense exothermic reaction, unstable mechanical properties, low drug loading efficiency, and uncontrollable drug release. In recent years, stimulus-responsive materials have become a research hotspot. Although ultrasonic response systems have been attempted for drug controlled release, due to the problems of limited energy attenuation and penetration depth of ultrasound in tissues, the regulation effect is still not ideal. Near-infrared penetrates only a few millimeters to about 1 centimeter in tissues, unable to reach deep lesions; and it relies on the surface or local absorption of heat effects, with limited control accuracy and prone to local overheating. pH response depends on local tissue pH changes, is a passive response, has weak spatial specificity, is difficult to precisely regulate externally, and is only suitable for the slightly acidic environment of tumors. In contrast, microwaves have stronger penetrability and controllable response, can precisely adjust the frequency, power, and time through instruments to achieve precise controlled release. At the same time, the local temperature rise is controllable and the biological safety is good. By introducing suitable microwave-sensitive materials, it is expected to achieve local heating and drug release on demand, thereby overcoming the limitations of the prior art and achieving a more precise therapeutic effect. As a bone repair material, the curing time and exothermic reaction of magnesium-based bone cement are affected by the hydration reaction rate; bacterial infection is one of the complications of orthopedic implant surgery, which may lead to surgical failure. Therefore, the antibacterial performance of bone cement is crucial. The current research needs to focus on breakthrough directions: by regulating the reaction activity of the material to extend the setting time of the cement, inhibit the reaction temperature rise, optimize the mechanical properties, and simultaneously endow it with antibacterial function and bone regeneration induction ability, so as to improve the clinical application adaptability of this material in bone defect repair. Summary of the Invention

[0003] Object of the Invention: The main object of the present invention is to provide a microwave-responsive drug-controlled release bone cement, to solve the problems of limited energy attenuation and penetration depth of ultrasound in tissues; infrared response unable to reach deep lesions and prone to local overheating; pH response depending on local tissue pH changes, being a passive response and lacking time control ability, and to improve the drug controlled release effect; to solve the problems of fast curing speed, high reaction temperature, low mid- and late-stage compressive strength, poor degradability, and low drug loading efficiency of magnesium-based bone cement in the prior art by adding a retarder and drug-loaded nanocapsules to the bone cement; the second object of the present invention is to provide a preparation method of the microwave-responsive drug-controlled release bone cement; the third object of the present invention is to provide the application of the microwave-responsive drug-controlled release bone cement in the preparation of bone repair materials.

[0004] Technical solution: The microwave-responsive drug-controlled release bone cement of the present invention is obtained by mixing a solid-phase bone repair powder containing a microwave-responsive drug-loaded nano-container and a liquid phase. Among them, the solid-phase powder includes 25-40 parts by mass of dead-burned magnesia powder, 15-25 parts by mass of phosphate powder, and 0.05-0.9 parts of a microwave-responsive drug nano-carrier, and the liquid phase includes 50-80 parts by mass of ultrapure water and 0.3-2.0 parts by mass of an acidic retarder.

[0005] Further, the microwave-responsive drug-loaded nano-container is prepared by loading a bone repair-promoting drug on a polypyrrole (PPy) / carbon nanotube (CNTs) nano-carrier modified by in-situ oxidative polymerization and then wrapping it with a microwave-responsive polymer.

[0006] Even further, the bone repair-promoting drug is one or more of bone morphogenetic protein BMP-2, teriparatide, compound peptide ao, salmon calcitonin, and sodium fluoride.

[0007] Further, the preparation of the polypyrrole (PPy) / carbon nanotube (CNTs) nano-carrier modified by in-situ oxidative polymerization includes the following steps:

[0008] (1) Add carbon nanotubes to a concentrated nitric acid and concentrated sulfuric acid solution, carry out a reflux reaction, dialysis purification, centrifugation, wash until neutral, and vacuum dry to obtain carboxylated carbon nanotubes;

[0009] (2) Disperse the carboxylated carbon nanotubes in deionized water, perform ultrasonic treatment, add pyrrole monomer, stir evenly, and slowly dropwise add a solution containing FeCl 3 ·6H 2 O and p-toluenesulfonic acid sodium, continue stirring, centrifuge, wash, and dry to obtain a CNT-PPy core-shell precursor;

[0010] (3) Place the CNT-PPy core-shell precursor in a radio frequency plasma reaction chamber, introduce an NH 3 / Ar mixed gas for treatment to form an N element gradient doping at the CNT-PPy interface, immerse it in a KH-550 ethanol solution, perform ultrasonic treatment, heat treatment, form a CNT-PPy composite network connected by Si-O-C covalent bonds, rapidly freeze, and vacuum dry to form through pores to obtain a PPy / CNTs nano-carrier.

[0011] Even further, the bone repair-promoting drug is one or more of puerarin, luteolin, compound peptide ao, sodium fluoride, teriparatide, and BMP-2, and the microwave-responsive polymer is one or more of polypyrrole, polylactic acid copolymer, poly(N-isopropylacrylamide), and PluronicF 68.

[0012] Further, the particle size of the PPy / CNTs nanocarrier is controlled between 400 and 700 nm, and the specific surface area is 350 - 760 m 2 / g.

[0013] Further, in step (1), the volume ratio of concentrated nitric acid to concentrated sulfuric acid is 1:(3 - 5), preferably 1:3, the weight ratio of carbon nanotubes to concentrated nitric acid is 0.5:(10 - 15), preferably 0.5:15, the reflux reaction temperature is 60 - 100 °C, preferably 80 °C, and the reflux reaction time is more than 6 h.

[0014] Further, in step (2), the mass ratio of pyrrole monomer to carboxylated carbon nanotubes is (3 - 5):1, preferably 3:1.

[0015] Further, in step (2), the sonication time is more than 30 min.

[0016] Further, in step (2), the weight ratio of FeCl 3 ·6H 2 O, sodium p-toluenesulfonate to carboxylated carbon nanotubes is (4 - 6):(4 - 6):0.5, preferably 5.5:5.5:0.5.

[0017] Further, in step (2), magnetic stirring is carried out at 0 - 5 °C for more than 12 h.

[0018] Further, in step (3), the volume ratio of NH 3 / Ar is 2:1, and the treatment time is more than 30 min.

[0019] Further, in step (3), sonication is carried out for more than 1 h, the heat treatment temperature is 80 - 100 °C, and the heat treatment time is more than 2 h.

[0020] Further, in step (3), after rapid freezing in liquid nitrogen, vacuum drying is carried out at -30 to -50 °C for more than 24 h.

[0021] Further, the PPy / CNTs nanocarrier is added to the osteoinductive drug solution, stirred, centrifuged, filtered, washed, and lyophilized at low temperature to obtain the drug-loaded nanocontainer.

[0022] Even further, the concentration of the osteoinductive drug solution is 1 - 10 mg / mL, the mass ratio of the PPy / CNTs nanocarrier to the osteoinductive drug solution is 50 - 90:60 - 100, the stirring speed is 400 - 600 rpm, the stirring time is 8 - 12 h, the low-temperature lyophilization temperature is below -20 °C, and the low-temperature lyophilization time is 5 - 10 h.

[0023] Furthermore, the drug-loaded nanocontainers are dispersed in a microwave-responsive polymer solution, stirred, centrifuged, filtered, washed, and freeze-dried at low temperature to obtain microwave-responsive drug-loaded nanocontainers.

[0024] Even further, the concentration of the microwave-responsive polymer solution is 1 - 5 mg / mL, the mass ratio of the drug-loaded nanocontainers to the microwave-responsive polymer solution is 1 - 2:10 - 20, the stirring speed is 400 - 600 rpm, and the stirring time is 4 - 8 h. The temperature for low-temperature freeze-drying is below -20°C, and the freeze-drying time is 5 - 10 h.

[0025] Furthermore, the acidic retarder is one or more of hyaluronic acid, sodium lignosulfonate, carboxymethyl cellulose, gluconic acid, glycerol, salicylic acid, and sodium alginate, and the pH of the acidic retarder is 3.8 - 4.9.

[0026] The preparation method of the microwave-responsive drug-controlled release bone cement of the present invention includes the following steps:

[0027] The microwave-responsive drug-loaded nanocontainers are mixed evenly with dead-burned magnesium oxide powder and potassium dihydrogen phosphate powder to form a solid phase, and an ultrapure aqueous solution containing an acidic retarder is added. After stirring evenly, injection molding is carried out to obtain the microwave-responsive drug-controlled release bone cement.

[0028] Furthermore, the potassium dihydrogen phosphate and the fine dead-burned magnesium oxide powder are respectively ball-milled in an agate ball mill for 5 - 10 h and then sieved with a standard sieve to obtain potassium dihydrogen phosphate and fine dead-burned magnesium oxide powder with a particle size of 60 - 85 μm.

[0029] Furthermore, the dead-burned magnesium oxide is obtained by calcining magnesium oxide at a high temperature of 1550 - 1750°C for 4 - 8 h.

[0030] Furthermore, the solid-liquid ratio of the solid-phase powder to the liquid-phase solution is 1 - 2 g / mL.

[0031] The application of the microwave-responsive drug-controlled release bone cement of the present invention in the preparation of bone repair materials.

[0032] In the solid-phase powder of the microwave-responsive drug-controlled release bone cement of the present invention, the dead-burned magnesia is formed by arc melting and fine grinding of light magnesia through optimized treatment. During this process, the arc treatment can reduce the hydration reaction activity of the bone cement, thereby reducing the heat release of the reaction. The use of an acidic retarder in the liquid phase solution can extend the curing time of the microwave-responsive drug-controlled release bone cement, also reduce the heat release of the hydration reaction, and even increase the compressive strength of the microwave-responsive drug-controlled release bone cement. Embedding the microwave-responsive drug-loaded nanocontainer into the framework of the microwave-responsive drug-controlled release bone cement can achieve the effect of microwave-responsive drug-controlled release. The drug is released on demand, improving the drug-loading efficiency and drug-loading capacity, and greatly enhancing the drug utilization rate and treatment effect. The microwave-responsive drug-controlled release bone cement has good injectability and can be arbitrarily shaped during the operation without being affected by the bone defect structure and location, which is beneficial to the perfect fit between the surrounding bone tissue and the bone cement. The microwave-responsive drug-controlled release bone cement degrades to produce magnesium ions and promotes the release of osteoinductive drugs, and the two can play a synergistic role in promoting bone formation. As a biomedical material, the microwave-responsive drug-controlled release bone cement has good biocompatibility and bioactivity, has antibacterial properties, can promote bone integration, promote the growth of vascular endothelial cells, and can be an ideal candidate material for bone repair materials.

[0033] As an electromagnetic wave, microwaves are widely used in the controlled release and selective activation of drugs. With the thermal and non-thermal effects of microwaves, the structural stability of drug carriers can be regulated to achieve the controlled release of drugs. At the same time, microwave energy can induce a local temperature increase, promote the phase change of polymer materials or the structural change of nanocarriers, and release the encapsulated drugs, resulting in an increase in the drug release rate after irradiation. In addition, compared with stimulation methods such as ultrasonic irradiation, the microwaves used in the present invention have stronger tissue penetration ability and can act on deep tissues non-invasively to achieve the precise activation and local release of drugs, improving the treatment effect.

[0034] In the present invention, a polymer material with microwave response is coated on the surface of the drug-loaded nanocontainer. Once exposed to external microwave radiation, the polypyrrole / carbon nanotube composite can quickly absorb microwave energy and generate a local thermal effect, increasing the temperature of the surrounding environment, thereby inducing the phase change of the polymer or the change of the pore structure of the drug-loaded nanocontainer, and increasing the drug diffusion channels. In addition, the non-thermal effect of microwaves can affect the molecular configuration of polymer materials, making their hydrophilic-hydrophobic properties reversibly change and increasing the drug release rate. The precise regulation ability of microwave radiation enables the present invention to achieve drug release on demand, improving the targeting and effectiveness of treatment.

[0035] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages:

[0036] (1) By introducing microwave-responsive polymers, the present invention realizes precise controlled release of drugs under microwave induction, overcoming the problem of difficult release regulation in traditional physical drug-doping methods.

[0037] (2) Utilizing the excellent microwave absorption performance of the polypyrrole / carbon nanotube composite, the bone cement can rapidly trigger drug release within the local temperature control range, and the temperature rise is controlled within a safe range to ensure the safety of surrounding tissues.

[0038] (3) The adjusted solid and liquid components endow the bone cement with good injectability, appropriate setting time, and excellent mechanical strength, while maintaining high biocompatibility and osteogenic effect.

[0039] (4) Compared with the ultrasonic response system, the microwave response technology has higher penetration ability and energy utilization efficiency, providing a new technical approach for clinical bone repair and local drug treatment.

[0040] (5) The CNT-PPy core-shell precursor of the present invention is prepared by in-situ oxidative polymerization method. After plasma gradient doping treatment and interfacial bridging with amino-silane coupling agent, it is prepared by freezing with liquid nitrogen to create pores. An acidic retarder is added to ultrapure water to form a liquid phase, which is mixed and stirred evenly with the solid-phase bone repair powder containing microwave-responsive drug-loaded nanocontainers, and then the bone cement is injection-molded. Drug release can be triggered under low-power microwave irradiation of 1 - 3W, and the cumulative release rates in 24 hours reach 45%, 68%, and 82% respectively.

[0041] (6) The CNT-PPy of the present invention adopts the "multi-level heterogeneous interface coupling" process to improve the microwave absorption efficiency, structural stability, and drug loading capacity. The temperature rise range of the bone cement is safe, the compressive strength is excellent, and the cell survival rate exceeds 92%. The deep tissue penetration ability of microwaves realizes more precise spatio-temporal control of drug release. The present invention takes into account both mechanical stability and precise drug release, and is applicable to bone defect repair and local drug treatment. Description of the Drawings

[0042] Figure 1 Scanning electron microscope test images of the microwave-responsive drug-controlled release bone cement samples obtained in Example 1, Comparative Example 1, and Comparative Example 3;

[0043] Figure 2 XRD test of the bone cement samples obtained in Example 1, Comparative Example 1, and Comparative Example 3;

[0044] Figure 3 Cumulative drug release rate graph of the microwave-responsive drug-controlled release bone cement obtained in Example 1;

[0045] Figure 4 Cumulative drug release rate graph of the ultrasonic-responsive drug-controlled release bone cement obtained in Comparative Example 4;

[0046] Figure 5 Curves of the curing temperatures of the bone cements obtained in Example 1 and Comparative Examples 1-3;

[0047] Figure 6 Curves of the compressive strengths of the bone cements obtained in Example 1 and Comparative Examples 1-3;

[0048] Figure 7 Curves of the cell activity tests of the bone cements obtained in Example 1, Comparative Example 1 and Comparative Example 3. Detailed implementation manners

[0049] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0050] Example 1

[0051] 1. Preparation of microwave-responsive drug-loaded nanocontainers

[0052] (1) Add 0.5 parts of carbon nanotubes (CNTs) to 15 parts of a concentrated nitric acid and concentrated sulfuric acid (volume ratio 1:3) solution, reflux at 80 °C for 6 h, and obtain carboxylated CNTs through dialysis purification; centrifuge to remove the acid solution, wash with deionized water until neutral, and vacuum dry to obtain modified CNTs. Take 0.5 parts of the modified CNTs and disperse them in 50 parts of deionized water, ultrasonically treat for 30 min to obtain a uniform suspension, then add pyrrole monomer (the mass ratio of modified CNTs to pyrrole is 5:1), stir evenly, and slowly add 5.5 parts of an oxidation / dopant solution containing FeCl 3 ·6H 2 O and p-toluenesulfonic acid sodium (the average concentrations of FeCl 3 ·6H 2 O and p-toluenesulfonic acid sodium in the solution are both 1%), magnetically stir the solution at 0-5 °C and 450 rpm for 12 h, centrifuge to collect the black precipitate, wash, and dry to obtain a CNT-PPy core-shell precursor. Place the CNT-PPy core-shell precursor in a radio frequency plasma reaction chamber, introduce an NH 3 / Ar mixed gas (the volume ratio of NH 3 to Ar is 2:1), treat for 30 min to form an N element gradient doping at the CNT-PPy interface. Immerse the plasma-treated material in a KH-550 ethanol solution, ultrasonically treat for 1 h, heat-treat at 80 °C for 2 h to form a CNT-PPy composite network connected by Si-O-C covalent bonds, rapidly freeze with liquid nitrogen, and then vacuum dry at -50 °C for 24 h to form through pores, and obtain a PPy / CNTs nanocarrier (polypyrrole-coated carbon nanotube composite material), with a particle size of 300 nm and a specific surface area of about 500 m2 / g.

[0053] (2) Mix 50 parts of PPy / CNTs nanocarriers with 60 parts of a drug solution of bone morphogenetic protein BMP-2 with a concentration of 1.0 mg / mL by mass. After stirring at 500 rpm for 8 h, obtain the drug-loaded nanocontainer through centrifugation, filtration, washing, and freeze-drying at -20 °C for 5 h.

[0054] (3) The microwave-responsive polymer is Pluronic F 68. Prepare a microwave-responsive polymer solution with a concentration of 1 mg / mL. Take 1 part of the drug-loaded nanocontainer by mass and disperse it in 10 parts of the microwave-responsive polymer solution. Stir at 400 rpm for 5 h, perform centrifugal separation, filtration, and cleaning, and then freeze-dry at -20 °C for 5 h to obtain a microwave-responsive drug-loaded nanocontainer with a microwave-responsive polymer coating on the outer surface of the drug-loaded nanocontainer.

[0055] 2. Preparation of microwave-responsive drug-controlled release bone cement

[0056] (1) Calcinate the magnesia raw material at a high temperature of 1550 °C for 4 h to obtain dead-burned magnesia.

[0057] (2) Ball-mill potassium dihydrogen phosphate and dead-burned magnesia in an agate ball-milling tank for 5 h respectively, and sieve them using a standard sieve to obtain fine powders of potassium dihydrogen phosphate and dead-burned magnesia with a particle size of 80 μm each.

[0058] (3) Take 15 parts of the fine powder of potassium dihydrogen phosphate, 25 parts of the fine powder of dead-burned magnesia, and add 0.5 part of the microwave-responsive drug-loaded nanocontainer by mass, and mix them evenly to obtain a solid-phase powder.

[0059] (4) Take 0.6 part of a sodium lignosulfonate solution with a concentration of 1 mg / mL and a pH of 4.8 and 50 parts of ultrapure water by mass, and stir them evenly to prepare a liquid-phase solution.

[0060] (5) Mix the solid-phase powder and the liquid-phase solution at a solid-liquid ratio of 1 g / mL and stir quickly by hand to form a microwave-responsive drug-controlled release bone cement slurry.

[0061] Example 2

[0062] 1. Preparation of microwave-responsive drug-loaded nanocontainer

[0063] (1) The preparation of the PPy / CNTs nanocarrier is the same as step (1) in Example 1. The difference is that the magnetic stirring speed in step (1) is 550 rpm, and the obtained PPy / CNTs nanocarrier has a particle size of 350 nm and a specific surface area of about 520 m2 / g.

[0064] (2) Add 60 parts of PPy / CNTs nanocarriers by mass to 72 parts of teriparatide solution with a concentration of 1.8 mg / mL, stir at 550 rpm for 8 h, perform centrifugal separation, filtration, washing, and freeze-dry at -20 °C for 5 h to obtain a drug-loaded nanocontainer;

[0065] (3) The microwave-responsive polymer is polylactic acid PLA. Prepare a microwave-responsive polymer solution with a concentration of 2 mg / mL. Take 1 part of the drug-loaded nanocontainer by mass and disperse it in 10 parts of the microwave-responsive polymer solution, stir at 400 rpm for 5 h, perform centrifugal separation, filtration, washing, and freeze-dry at -20 °C for 5 h to obtain a microwave-responsive drug-loaded nanocontainer with a microwave-responsive polymer coating on the outer surface of the drug-loaded nanocontainer.

[0066] 2. Preparation of microwave-responsive drug-controlled release bone cement

[0067] (1) Calcinate the magnesia raw material at a high temperature of 1600 °C for 5 h to obtain dead-burned magnesia;

[0068] (2) Ball-mill potassium dihydrogen phosphate and dead-burned magnesia separately in an agate ball-milling tank for 5 h, and sieve using a standard sieve to obtain fine powders of potassium dihydrogen phosphate and dead-burned magnesia with a particle size of 75 μm;

[0069] (3) Take 24 parts of the fine powder of potassium dihydrogen phosphate, 40 parts of the fine powder of dead-burned magnesia, and add 0.6 part of the microwave-responsive drug-loaded nanocontainer by mass, and mix evenly to obtain a solid-phase powder;

[0070] (4) Take 0.8 part of a sodium alginate solution with a concentration of 1 mg / mL and a pH of 4.0 and 50 parts of ultrapure water by mass, stir evenly to prepare a liquid-phase solution;

[0071] (5) Mix the solid-phase powder and the liquid-phase solution at a solid-liquid ratio of 2 g / mL and stir quickly by hand to form a microwave-responsive drug-controlled release bone cement slurry.

[0072] Example 3

[0073] 1. Preparation of microwave-responsive drug-loaded nanocontainer

[0074] (1) The preparation of the PPy / CNTs nanocarrier is the same as step (1) in Example 1, except that the magnetic stirring speed in step (1) is 600 rpm to obtain a PPy / CNTs nanocarrier with a particle size of 380 nm and a specific surface area of about 530 m2 / g;

[0075] (2) Add 60 parts of PPy / CNTs nanocarriers by mass to 65 parts of the compound peptide A solution with a concentration of 3 mg / mL, stir at 500 rpm for 6 h, perform centrifugal separation, filtration, washing, and freeze-dry at -20 °C for 5 h to obtain the drug-loaded nanocontainer;

[0076] (3) The microwave-responsive polymer is polypyrrole. Prepare a microwave-responsive polymer solution with a concentration of 3 mg / mL. Take 1.5 parts of the drug-loaded nanocontainer by mass and disperse it in 20 parts of the microwave-responsive polymer solution, stir at 500 rpm for 8 h, perform centrifugal separation, filtration, washing, and freeze-dry at -20 °C for 5 h to obtain a microwave-responsive drug-loaded nanocontainer with a microwave-responsive polymer coating on the outer surface of the drug-loaded nanocontainer.

[0077] 2. Preparation of microwave-responsive drug-controlled release bone cement

[0078] (1) Calcinate the magnesia raw material at a high temperature of 1700 °C for 4 h to obtain dead-burned magnesia;

[0079] (2) Ball-mill potassium dihydrogen phosphate and dead-burned magnesia in an agate ball-milling tank for 8 h respectively, and sieve them using a standard sieve to obtain potassium dihydrogen phosphate fine powder and dead-burned magnesia fine powder with a particle size of 65 μm;

[0080] (3) Take 20 parts of potassium dihydrogen phosphate fine powder, 35 parts of dead-burned magnesia fine powder by mass, and then add 0.5 part of the microwave-responsive drug-loaded nanocontainer, and mix evenly to obtain a solid-phase powder;

[0081] (4) Take 0.9 part of glycerol solution with a concentration of 5 mg / mL and a pH of 4.5 and 60 parts of ultrapure water by mass, stir evenly to prepare a liquid-phase solution;

[0082] (5) Mix the solid-phase powder and the liquid-phase solution according to a solid-liquid ratio of 3 g / mL and stir quickly by hand to form a microwave-responsive drug-controlled release bone cement slurry.

[0083] Example 4

[0084] 1. Preparation of microwave-responsive drug-loaded nanocontainer

[0085] (1) The preparation of the PPy / CNTs nanocarrier is the same as step (1) in Example 1, except that the magnetic stirring speed in step (1) is 650 rpm to obtain the PPy / CNTs nanocarrier with a diameter of 390 nm and a specific surface area of about 540 m2 / g;

[0086] (2) Add 80 parts of PPy / CNTs nanocarriers by mass to 95 parts of salmon calcitonin solution with a concentration of 3 mg / mL, stir at 650 rpm for 8 h, perform centrifugal separation, filtration, washing, and freeze-dry at -20 °C for 5 h to obtain a drug-loaded nanocontainer;

[0087] (3) The microwave-responsive polymer is poly(N-isopropylacrylamide-co-acrylic acid). Prepare a microwave-responsive polymer solution with a concentration of 4 mg / mL. Take 2 parts of the drug-loaded nanocontainer by mass and disperse it in 18 parts of the microwave-responsive polymer solution, stir at 650 rpm for 8 h, perform centrifugal separation, filtration, washing, and freeze-dry at -20 °C for 5 h to obtain a microwave-responsive drug-loaded nanocontainer with a microwave-responsive polymer coating on the outer surface of the drug-loaded nanocontainer.

[0088] 2. Preparation of microwave-responsive drug-controlled release bone cement

[0089] (1) Calcinate the magnesia raw material at a high temperature of 1750 °C for 4 h to obtain dead-burned magnesia;

[0090] (2) Ball-mill potassium dihydrogen phosphate and dead-burned magnesia separately in an agate ball-milling tank for 7 h, and sieve using a standard sieve to obtain fine powders of potassium dihydrogen phosphate and dead-burned magnesia with a particle size of 70 μm;

[0091] (3) Take 20 parts of the fine powder of potassium dihydrogen phosphate, 40 parts of the fine powder of dead-burned magnesia, and add 0.7 part of the microwave-responsive drug-loaded nanocontainer by mass, and mix evenly to obtain a solid-phase powder;

[0092] (4) Take 0.9 part of a salicylic acid solution with a concentration of 3 mg / mL and a pH of 3.8 and 65 parts of ultrapure water by mass, stir evenly to prepare a liquid-phase solution;

[0093] (5) Mix the solid-phase powder and the liquid-phase solution according to a solid-liquid ratio of 2 g / mL and stir quickly by hand to form a microwave-responsive drug-controlled release bone cement slurry.

[0094] Example 5

[0095] 1. Preparation of microwave-responsive drug-loaded nanocontainer

[0096] (1) The preparation of the PPy / CNTs nanocarrier is the same as step (1) in Example 1, except that the magnetic stirring speed in step (1) is 700 rpm to obtain a PPy / CNTs nanocarrier with a particle size of 400 nm and a specific surface area of about 550 m2 / g;

[0097] (2) Add 90 parts of PPy / CNTs nanocarriers by mass to 100 parts of sodium fluoride solution with a concentration of 4 mg / mL, stir at 800 rpm for 5 h, perform centrifugal separation, filtration, washing, and freeze-dry at -20 °C for 5 h to obtain drug-loaded nanocontainers;

[0098] (3) The microwave-responsive polymer is polylactic acid PLA. Prepare a microwave-responsive polymer solution with a concentration of 2 mg / mL. Take 2 parts of the drug-loaded nanocontainers by mass and disperse them in 17 parts of the microwave-responsive polymer solution, stir at 700 rpm for 5 h, perform centrifugal separation, filtration, washing, and freeze-dry at -20 °C for 5 h to obtain microwave-responsive drug-loaded nanocontainers with a microwave-responsive polymer coating on the outer surface of the drug-loaded nanocontainers.

[0099] 2. Preparation of microwave-responsive drug-controlled release bone cement

[0100] (1) Calcinate the magnesia raw material at a high temperature of 1750 °C for 4.5 h to obtain dead-burned magnesia;

[0101] (2) Ball-mill potassium dihydrogen phosphate and dead-burned magnesia separately in an agate ball-milling tank for 5 h, and sieve them using a standard sieve to obtain fine powders of potassium dihydrogen phosphate and dead-burned magnesia with a particle size of 85 μm;

[0102] (3) Take 25 parts of the fine powder of potassium dihydrogen phosphate and 38 parts of the fine powder of dead-burned magnesia by mass, and then add 0.6 part of the microwave-responsive drug-loaded nanocontainers, and mix them evenly to obtain a solid-phase powder;

[0103] (4) Take 1.5 parts of a hyaluronic acid solution with a concentration of 3 mg / mL and a pH of 4.9 and 60 parts of ultrapure water by mass, stir them evenly to prepare a liquid-phase solution;

[0104] (5) Mix the solid-phase powder and the liquid-phase solution according to a solid-liquid ratio of 3 g / mL and stir quickly by hand to form a microwave-responsive drug-controlled release bone cement slurry.

[0105] Comparative Example 1 does not use an acid retarder and does not add microwave-responsive drug-loaded nanocontainers

[0106] The preparation process is the same as that in Example 1, except that: do not use the sodium lignosulfonate solution, only take 50 parts of ultrapure water as the liquid-phase solution, and do not add microwave-responsive drug-loaded nanocontainers to the solid-phase powder to prepare HO-MPCs. 2 O-MPCs.

[0107] Comparative Example 2 uses hyaluronic acid to replace sodium lignosulfonate and does not add microwave-responsive drug-loaded nanocontainers

[0108] The preparation process was the same as that of Example 1, except that: 0.6 parts of hyaluronic acid and 50 parts of ultrapure water were taken as the liquid-phase solution, and the microwave-responsive drug-loaded nanocontainers were not added to the solid-phase powder, and HA-MPC was prepared.

[0109] In Comparative Example 3, the microwave-responsive drug-loaded nanocontainers were not added.

[0110] The preparation process was the same as that of Example 1, except that: the microwave-responsive drug-loaded nanocontainers were not added to the solid-phase powder, and SLS(6)-MPC was prepared.

[0111] In Comparative Example 4, the ultrasonic-responsive drug-loaded nanocontainers were used to replace the microwave-responsive drug-loaded nanocontainers.

[0112] The preparation process was the same as that of Example 1, except that: the ultrasonic-responsive drug-loaded nanocontainers were used to replace the microwave-responsive drug-loaded nanocontainers. The preparation method of the ultrasonic-responsive drug-loaded nanocontainers referred to Example 1 in CN 117547643 A, and the drug selected was BMP-2.

[0113] Scanning electron microscopy tests were carried out on the bone cement samples obtained in Example 1 and Comparative Examples 1 and 3, and the results were as Figure 1 shown. The surface of the sample of Example 1 (NPs-SLS-MPC) doped with sodium lignosulfonate and microwave-responsive drug-loaded nanocontainers was denser than that of Comparative Example 3 (SLS(6)-MPC), and the crack defects were significantly fewer than those of Comparative Example 1 (H 2 O-MPCs) group. Therefore, doping the microwave-responsive drug-loaded nanocontainers in the present application can improve the mechanical properties of the magnesium-based bone cement.

[0114] XRD tests were carried out on the bone cement samples obtained in Example 1 and Comparative Examples 1 and 3, and the results were as Figure 2 shown. Figure 2 is the XRD pattern of the bone cement obtained in Example 1 and Comparative Examples 1 and 3. Among them, H 2 O-MPCs is Comparative Example 1, SLS(6)-MPC is Comparative Example 3, and NPs-SLS-MPC is Example 1. It can be Figure 2 seen that the XRD spectra of the three bone cements all contain the absorption peaks of KMgPO 4 ·6H 2 O and MgO, indicating that the final hydration product of the bone cement is KMgPO 4 ·6H 2 O, and there is unreacted MgO, which is because slightly excessive MgO helps to improve the strength of the microwave-responsive drug-controlled release bone cement. The XRD test shows that the addition of sodium lignosulfonate does not affect the effective components of the hydration products of the bone cement.

[0115] The microwave-responsive drug-controlled release test was carried out on the bone cement samples obtained in Example 1. Three different power gradients (1W, 2W, 3W) were set. Each sample was placed in a 15 mL centrifuge tube, and 10 mL of pH 7.4 PBS buffer solution was added. A 2.45 GHz laboratory-grade microwave generator was used, and the output power was set to 1 - 3W. The irradiation time was 1 min / h, and the total duration was 24 h. 1 mL of the sample was taken at 4h, 8h, 12h, 16h, 20h, and 24h, and an equal volume of fresh PBS was replenished. The concentration of BMP-2 was quantitatively monitored by ELISA, and the cumulative release rate at each time point was calculated. The results are as Figure 3 shown, Figure 3 is the cumulative release rate graph of the bone cement drug obtained in Example 1. It can be seen from Figure 3 that for the microwave-responsive drug-controlled release bone cement samples doped with microwave-responsive drug-loaded nanocontainers in Example 1, under the action of a 2.45 GHz microwave generator at 1W / cm 2 , 2W / cm 2 and 3W / cm 2 , the cumulative release rates at 24 hours reached 45%, 68%, and 82% respectively, all of which could control the drug release rate. Moreover, as the microwave power increased, the cumulative drug release was more. The data showed that the drug release rate was positively correlated with the microwave power. The microwave-responsive drug-controlled release was successfully achieved.

[0116] The 2.45 GHz ultrasonic-responsive drug-controlled release test was carried out on the bone cement samples obtained in Comparative Example 4. The results are as Figure 4 shown, Figure 4 is the cumulative release rate graph of the bone cement drug obtained in Comparative Example 4. It can be seen from Figure 4 that for the ultrasonic-responsive drug-controlled release bone cement samples doped with ultrasonic-responsive drug-loaded nanocontainers in Comparative Example 1, under the action of a 2.45 GHz microwave at 1W / cm 2 , 2W / cm 2 and 3W / cm 2 , the cumulative drug release rate was lower than that in Example 1.

[0117] The hydration reaction temperature and compressive strength tests were carried out on the bone cement samples obtained in Example 1 and Comparative Examples 1 - 3. The hydration reaction temperature was measured by a temperature sensor, and the compressive strength was measured by an Instron + MTS universal testing machine. The results are as Figure 5 shown. Figure 5 is the curing temperature graph of the bone cement obtained in Example 1 and Comparative Examples 1 - 3. Among them, H 2 O-MPCs is Comparative Example 1, HA-MPC is Comparative Example 2, SLS(6)-MPC is Comparative Example 3, and NPs-SLS-MPC is Example 1. It can be seen from Figure 5It can be seen that the maximum hydration reaction temperature of Comparative Example 2 and Comparative Example 3 is lower than that of Comparative Example 1, indicating that the retarder can reduce the intensity of the hydration reaction. The maximum hydration reaction temperature of Example 1 with the retarder and the microwave-responsive drug-loaded nanocontainer is the lowest, at 35 °C, indicating that the addition of the microwave-responsive drug-loaded nanocontainer can reduce the intensity of the hydration reaction, inhibit the heat release of hydration, and reduce the damage to human tissues.

[0118] Figure 6 Figure showing the compressive strength of the bone cements obtained in Example 1 and Comparative Examples 1-3, where H 2 O-MPCs is Comparative Example 1, HA-MPC is Comparative Example 2, SLS(6)-MPC is Comparative Example 3, and NPs-SLS-MPC is Example 1 Figure 6 It can be seen that the compressive strength of Comparative Example 2 and Comparative Example 3 with the retarder added is higher than that of Comparative Example 1. The compressive strength of the bone cement sample in Example 1 is the highest, reaching 48.726 MPa, indicating that adding a retarder to the liquid phase composition and doping the solid phase with microwave-responsive drug-loaded nanocontainers can significantly enhance the compressive strength of the bone cement.

[0119] Cell viability tests were performed on the bone cement samples obtained in Example 1 and Comparative Examples 1 and 3, and the results are as Figure 7 shown. Figure 7 Figure showing the cell viability test of the bone cements obtained in Example 1 and Comparative Examples 1 and 3, where NPs-SLS-MPC is Example 1, H 2 O-MPCs is Comparative Example 1, and SLS(6)-MPC is Comparative Example 3. Figure 7 It can be seen that the bone cements obtained in Example 1 and Comparative Examples 1 and 3 all have good osteogenic growth activity, and as the culture time increases, the cell viability increases. The sample in Example 1 shows the best cell compatibility in vitro, with a cell survival rate exceeding 92%, which is beneficial to promoting cell proliferation. Therefore, the bone cement doped with microwave-responsive drug-loaded nanocontainers in Example 1 has good proliferation ability and osteogenic effect on cells.

Claims

1. A microwave responsive drug controlled release bone cement, characterized in that: The bone cement is obtained by mixing a solid phase bone repair powder containing a microwave responsive drug-loaded nanocontainer and a liquid phase, wherein the solid phase powder comprises 25 to 40 parts by mass of dead-burned magnesium oxide powder, 15 to 25 parts by mass of phosphate powder and 0.05 to 0.9 parts by mass of microwave responsive drug nanocarriers, and the liquid phase comprises 50 to 80 parts by mass of ultrapure water and 0.3 to 2.0 parts by mass of an acidic retarder.

2. The microwave responsive drug controlled release bone cement according to claim 1, characterized in that: The microwave-responsive drug-loaded nanocontainer is prepared by loading bone repair-promoting drugs onto polypyrrole (PPy) / carbon nanotube (CNTs) nanocarriers modified by in-situ oxidative polymerization and then wrapping them with microwave-responsive polymers.

3. The microwave responsive drug controlled release bone cement according to claim 2, characterized in that: The preparation of the polypyrrole (PPy) / carbon nanotube (CNTs) nanocarrier modified by in-situ oxidative polymerization comprises the following steps: (1) adding carbon nanotubes to concentrated nitric acid and concentrated sulfuric acid solutions, reflux reaction, dialysis purification, centrifugation, washing to neutrality, and vacuum drying to obtain carboxylated carbon nanotubes; (2) dispersing carboxylated carbon nanotubes in deionized water, ultrasonically treating, adding pyrrole monomer, stirring evenly, slowly dropping a solution containing FeCl3·6H2O and sodium p-toluenesulfonate, continuing stirring, centrifuging, washing, and drying to obtain a CNT-PPy core-shell precursor; (3) The CNT-PPy core-shell precursor is placed in a radio frequency plasma reaction chamber, and treated with a NH3 / Ar mixed gas to form a N element gradient doping at the CNT-PPy interface. The precursor is immersed in a KH-550 ethanol solution, ultrasonically treated, and heat treated to form a CNT-PPy composite network connected by Si-OC covalent bonds. The precursor is rapidly frozen and vacuum dried to form through-holes to obtain a PPy / CNTs nanocarrier.

4. The microwave responsive drug controlled release bone cement according to claim 3, characterized in that: The bone repair promoting drug is one or more of puerarin, luteolin, complex peptide, sodium fluoride, teriparatide and BMP-2, and the microwave responsive polymer is one or more of polypyrrole, polylactic acid copolymer, poly (N-isopropylacrylamide) and PluronicF 68.

5. The microwave responsive drug controlled release bone cement according to claim 3, characterized in that: The PPy / CNTs nanocarrier is added to the bone repair promoting drug solution, stirred, centrifuged, filtered, washed, and freeze-dried to obtain a drug-loaded nanocontainer, wherein the concentration of the bone repair promoting drug solution is 1-10 mg / mL, the mass ratio of the PPy / CNTs nanocarrier to the bone promoting drug solution is 50-90:60-100, the stirring speed is 400-600 rpm, the stirring time is 8-12 h, the freeze-drying temperature is below -20°C, and the freeze-drying time is 5-10 h.

6. The microwave responsive drug controlled release bone cement according to claim 5, characterized in that: The drug-loaded nanocontainer is dispersed in a microwave-responsive polymer solution, stirred, centrifuged, filtered, washed, and freeze-dried to obtain a microwave-responsive drug-loaded nanocontainer, wherein the concentration of the microwave-responsive polymer solution is 1-5 mg / mL, the mass ratio of the drug-loaded nanocontainer to the microwave-responsive polymer solution is 1-2:10-20, the stirring speed is 400-600 rpm, the stirring time is 4-8 hours, the freeze-drying temperature is below -20°C, and the freeze-drying time is 5-10 hours.

7. The microwave responsive drug controlled release bone cement according to claim 1, characterized in that: The acidic retarder is one or more of hyaluronic acid, sodium lignin sulfonate, carboxymethyl cellulose, gluconic acid, glycerol, salicylic acid, and sodium alginate, and the pH of the acidic retarder is 3.8-4.

9.

8. The method for preparing the microwave responsive drug controlled release bone cement according to any one of claims 1 to 7, characterized in that: The following steps are involved: The microwave responsive drug-loaded nano-container is mixed evenly with dead-burned magnesium oxide powder and potassium dihydrogen phosphate powder to form a solid phase, an ultrapure aqueous solution containing an acidic retarder is added, and the mixture is stirred evenly and then injection-molded to obtain a microwave responsive drug controlled-release bone cement.

9. The preparation method according to claim 8, characterized in that: The potassium dihydrogen phosphate and dead-burned magnesium oxide fine powders are obtained by ball-milling in an agate ball mill for 5 to 10 hours and then sieving with a standard sieve to obtain potassium dihydrogen phosphate and dead-burned magnesium oxide fine powders with a particle size of 60 to 85 μm; the dead-burned magnesium oxide is obtained by calcining magnesium oxide at a high temperature of 1550 to 1750° C. for 4 to 8 hours; the solid-to-liquid ratio of the solid phase powder to the liquid phase solution is 1 to 2 g / mL.

10. Use of the microwave responsive drug controlled-release bone cement according to any one of claims 1 to 7 in the preparation of bone repair materials.

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