Orthopedic repair bone cement and method of making same

Abstract

The application discloses a bone cement for orthopedic repair and a preparation method thereof, and relates to the technical field of bone cement.The bone cement for orthopedic repair comprises solid-phase powder and liquid-phase components; the solid-phase powder comprises the following components in parts by weight: 55-65 parts of composite calcium phosphate salt, 10-15 parts of bioactive glass, 2-3 parts of developing agent, 1-2 parts of hydroxyapatite, 8-12 parts of modified toughening agent and 2-3 parts of nanocellulose fiber; and the liquid-phase components comprise the following components in parts by weight: 40-50 parts of sodium alginate solution, 10-20 parts of methacrylated gelatin, 0.5-1 part of transglutaminase, 30-60 parts of citric acid buffer and 1-2 parts of antibacterial agent. The intermediate 1 is obtained by the reaction of pentaerythritol and 12-oxododecanoic acid, and the modified toughening agent is prepared by the reaction of the intermediate 1 and dopamine. The bone cement for orthopedic repair prepared by the application has good mechanical properties, self-repairing performance and antibacterial performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bone cement, in particular to a bone cement for orthopedic repair and a preparation method thereof. BACKGROUND

[0002] Bone cement (such as polymethyl methacrylate bone cement, calcium phosphate cement) is a commonly used filling and fixing material in orthopedic clinical practice, and is widely used in scenarios such as fracture fixation, artificial joint replacement, vertebroplasty, etc. Among them, calcium phosphate cement has become an ideal choice to replace traditional polymethyl methacrylate bone cement (non-degradable, heat damage) due to its similar inorganic components to human bone tissue, degradability and bone conduction. However, the existing calcium phosphate cement still has some technical problems, which limits its clinical application. Calcium phosphate cement is mainly formed by mixing calcium phosphate powder with liquid phase and solidifying, and its crystal structure is dense but lacks toughness, which is easy to cause implant fragmentation due to the accumulation of micro-cracks, especially in the repair of weight-bearing bones, the failure rate is relatively high. Traditional toughening methods (such as adding linear polymers, fibers) have the problems of weak interfacial bonding and easy agglomeration, and it is difficult to balance strength and toughness, and the self-repairing ability of calcium phosphate cement is also insufficient. In addition, bone cement implantation is prone to infection, and the existing antibiotic-loaded bone cement has the risk of "burst release" and "drug resistance", and silver ion-loaded materials may cause cytotoxicity.

[0003] The Chinese invention patent with publication number CN120204462A discloses a high-bending-resistant injectable magnesium phosphate bone cement and a preparation method thereof. The high-bending-resistant injectable magnesium phosphate bone cement comprises a solid phase powder, a reinforcing filler and water, the solid phase powder comprises the following components in parts by weight: magnesium phosphate salt 50-70 parts, hydrogen phosphate salt 30-50 parts, the magnesium phosphate salt comprises trimagnesium phosphate; the reinforcing filler comprises polyurethane modified epoxy resin emulsion; based on the polyurethane modified epoxy resin emulsion with a solid content of 30%-50%, the mass fractions of the solid phase powder, the reinforcing filler and the water in the bone cement are 66-70wt%, 1-7wt% and 23-33wt% respectively. The high-bending-resistant injectable magnesium phosphate bone cement has high bending strength and is suitable for bone defect areas that bear multidirectional load, but its antibacterial performance is poor and lacks self-repairing ability. SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a bone cement for orthopedic repair and a preparation method thereof.

[0005] To achieve the above-mentioned purpose, the technical scheme is as follows:

[0006] A bone cement for orthopedic repair, comprising a solid phase powder and a liquid phase component.

[0007] The solid-phase powder comprises the following components in parts by weight: 55-65 parts of composite calcium phosphate salt, 10-15 parts of bioactive glass, 2-3 parts of developing agent, 1-2 parts of hydroxyapatite, 8-12 parts of modified toughening agent, and 2-3 parts of nanocellulose fiber.

[0008] The liquid-phase component comprises the following components in parts by weight: 40-50 parts of sodium alginate solution, 10-20 parts of methacrylated gelatin, 0.5-1 part of transglutaminase, 30-60 parts of citric acid buffer, and 1-2 parts of antibacterial agent.

[0009] The modified toughening agent is prepared by the following method:

[0010] S1: Under nitrogen protection, pentaerythritol and 12-oxododecanoic acid are uniformly mixed with anhydrous toluene, 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 4-dimethylaminopyridine are added, and reaction is carried out at 80-100℃ for 6-8h to obtain intermediate 1;

[0011] S2: Under nitrogen protection, intermediate 1 and dopamine are uniformly mixed with anhydrous ethanol, triethylamine and ascorbic acid are added, and reaction is carried out at 30-40℃ for 5-7h to obtain the modified toughening agent.

[0012] In step S1, the molar ratio of pentaerythritol to 12-oxododecanoic acid is 1:(4.1-4.3).

[0013] In step S2, the molar ratio of intermediate 1 to dopamine is 1:(4.05-4.2).

[0014] The antibacterial agent is prepared by the following method:

[0015] N1: Under nitrogen protection, polydopamine is uniformly mixed with anhydrous DMF, triethylamine is uniformly mixed, and then 4-aminosulfonyl benzoyl chloride is added, and reaction is carried out at 30-40℃ for 5-7h to obtain intermediate A;

[0016] N2: Under nitrogen protection, gallic acid is uniformly mixed with anhydrous DMF, 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide are activated, then PBS buffer solution of intermediate A is slowly added, and reaction is carried out at 25-30℃ for 7-9h to obtain the antibacterial agent.

[0017] In step N1, the mass ratio of polydopamine to 4-aminosulfonyl benzoyl chloride is 1:(0.46-0.51).

[0018] In step N2, the mass ratio of intermediate A to gallic acid is 1:(0.25-0.27).

[0019] The composite calcium phosphate salt comprises alpha-tricalcium phosphate and beta-tricalcium phosphate, wherein the weight percentage of alpha-tricalcium phosphate is 70%, and the weight percentage of beta-tricalcium phosphate is 30%; the developer is tantalum powder; and the nanocellulose fiber is bacterial cellulose.

[0020] The concentration of the sodium alginate solution is 2 wt%, and the concentration of the citric acid buffer is 0.1 M, and the pH is 6.5.

[0021] A preparation method of bone cement for orthopedic repair, comprising the following steps:

[0022] (1) The following components are weighed by weight parts: composite calcium phosphate salt 55-65 parts, bioactive glass 10-15 parts, developer 2-3 parts, hydroxyapatite 1-2 parts, modified toughening agent 8-12 parts, nanocellulose fiber 2-3 parts, sodium alginate solution 40-50 parts, methacrylated gelatin 10-20 parts, transglutaminase 0.5-1 part, citric acid buffer 30-60 parts, and antibacterial agent 1-2 parts;

[0023] (2) The nanocellulose fiber is first freeze-dried to obtain dried nanocellulose fiber, and then the composite calcium phosphate salt, bioactive glass, developer, hydroxyapatite, dried nanocellulose fiber and modified toughening agent are mixed in a three-dimensional mixer to obtain a solid-phase powder;

[0024] (3) The methacrylated gelatin is mixed with the citric acid buffer, stirred and mixed uniformly in a 60℃ water bath, and cooled to room temperature in the dark; the transglutaminase and the antibacterial agent are added to the sodium alginate solution, and ultrasonically dispersed for 5 min at 300 W; the above two solutions are mixed under light-proof conditions, and stirred to obtain a liquid-phase component;

[0025] (4) The solid-phase powder and the liquid-phase component are mixed uniformly at a mass ratio of 3:1, and stirred to obtain the bone cement for orthopedic repair.

[0026] Due to the above technical solutions, the application has the following beneficial effects:

[0027] (1) The modified toughening agent prepared by the application can construct a four-arm Schiff base dynamic network through aldehyde-amino condensation, and can simultaneously endow the bone cement with mechanical properties, self-repairing properties, interfacial bonding strength and anti-fatigue properties. When a micro-crack occurs in the bone cement, the Schiff base bond can be triggered to hydrolyze and break through body fluid infiltration, and can be re-condensed to form a new Schiff base bond at a physiological pH, so that the "damage-repair" cycle can be realized; the hydroxyl groups on the surface of the modified toughening agent can form a coordination bond with calcium ions on the surface of the calcium phosphate, and can form a hydrogen bond with the hydroxyapatite, so as to improve the interfacial bonding strength; the dynamic Schiff base bond can dissipate energy through "breakage-recombination" under cyclic loading, thereby prolonging the in-vivo service life of the bone cement.

[0028] (2) The antibacterial agent prepared in the application is grafted with gallic acid on the surface of polydopamine, the phenolic hydroxyl group of gallic acid can destroy the bacterial cell membrane, inhibit the formation of biofilm, and improve the antibacterial performance; polydopamine itself has excellent biocompatibility and antioxidant properties, and the grafting of polydopamine with gallic acid can greatly improve the antibacterial performance of bone cement through synergistic effect. DETAILED DESCRIPTION

[0029] The application will be further described below in conjunction with examples, but the application is not limited to these examples.

[0030] Example 1: Preparation of modified toughening agent

[0031] S1: Under nitrogen protection, 0.1 mol of pentaerythritol and 0.41 mol of 12-oxododecanoic acid were added to 800 ml of anhydrous toluene, stirred and mixed, 0.4 mol of 1-ethyl-(3-dimethylaminopropyl) carbonyldiimide hydrochloride and 0.1 mol of 4-dimethylaminopyridine were added, and the mixture was reacted at 80°C for 8 h, filtered, rotary evaporated at 60°C for 3 h, purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 5:1), rotary evaporated at 50°C for 3 h, and the intermediate 1 was obtained; the reaction equation is as follows: V / V

[0032]

[0033] The nuclear magnetic resonance hydrogen spectrum data are as follows:

[0034] 1 H NMR (500 MHz, Chloroform- d ) δ 9.57 (s, 4H), 4.31-4.16 (m, 8H),2.51 (s, 8H), 2.30 (s, 8H), 1.59 (d, J = 2.4 Hz, 16H), 1.37-1.24 (m, 48H).

[0035] S2: Under nitrogen protection, 0.1 mol of intermediate 1 and 0.405 mol of dopamine were added to 900 ml of anhydrous ethanol, stirred and mixed, 0.1 mol of triethylamine and 0.05 mol of ascorbic acid were added, and the mixture was reacted at 30°C in the dark for 7 h; 1M hydrochloric acid was added to adjust the pH to 5, and the mixture was rotary evaporated at 40°C for 5 h; the residue was dissolved in 1000 ml of anhydrous ethanol / water (the volume ratio of anhydrous ethanol to water was 1:14), dialyzed (molecular weight cut-off 1000 Da) with deionized water containing 0.1 wt% ascorbic acid for 72 h (2000 ml of liquid was replaced every 6 hours), and freeze-dried at-50°C for 24 h to obtain the modified toughening agent; the reaction equation is as follows:

[0036] ​

[0037] Its 1H NMR data are as follows:

[0038] 1 H NMR (500 MHz, Chloroform- d ) δ 7.39 (d, J = 86.1 Hz, 4H), 6.71-6.64(m, 12H), 6.19 (d, J = 50.6 Hz, 8H), 4.32-4.15 (m, 8H), 3.79 (s, 8H), 2.84(d, J = 0.9 Hz, 8H), 2.30 (s, 8H), 2.10 (s, 8H), 1.59 (s, 8H), 1.57 (s, 8H), 1.35-1.26 (m, 48H).

[0039] Example 2: Preparation of modified toughening agent:

[0040] S1: Under nitrogen protection, 0.1 mol pentaerythritol and 0.42 mol 12-oxododecanoic acid were added to 800 mL of anhydrous toluene and stirred until homogeneous. Then, 0.4 mol 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.1 mol 4-dimethylaminopyridine were added. The mixture was reacted at 85 °C for 7 h, filtered, and rotary evaporated at 60 °C for 3 h. The mixture was then subjected to silica gel column chromatography (eluent: petroleum ether / ethyl acetate). V / V Purify the mixture by a ratio of 5:1, and rotary evaporate at 50°C for 3 hours to obtain intermediate 1;

[0041] S2: Under nitrogen protection, 0.1 mol of intermediate 1 and 0.41 mol of dopamine were added to 900 ml of anhydrous ethanol and stirred until homogeneous. Then, 0.1 mol of triethylamine and 0.05 mol of ascorbic acid were added, and the mixture was reacted at 35°C in the dark for 6 h. 1 M hydrochloric acid was added to adjust the pH to 5, and the mixture was rotary evaporated at 40°C for 5 h. The residue was dissolved in 1000 ml of anhydrous ethanol / water (anhydrous ethanol to water volume ratio of 1:14), dialyzed with deionized water containing 0.1 wt% ascorbic acid (molecular weight cutoff 1000 Da) for 72 h (the solution was changed every 6 hours, 2000 ml each time), and freeze-dried at -50°C for 24 h to obtain the modified toughening agent.

[0042] Example 3: Preparation of modified toughening agent:

[0043] S1: under nitrogen protection, 0.1 mol pentaerythritol and 0.43 mol 12-oxododecanoic acid were added into 800 ml anhydrous toluene, stirred and mixed, 0.4 mol 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 0.1 mol 4-dimethylaminopyridine were added, 90°C reaction for 6 h, filtration, 60°C rotary evaporation for 3 h, silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 5:1) purification, 50°C rotary evaporation for 3 h, to obtain intermediate 1; V / V

[0044] S2: under nitrogen protection, 0.1 mol intermediate 1, 0.42 mol dopamine were added into 900 ml anhydrous ethanol, stirred and mixed, 0.1 mol triethylamine and 0.05 mol ascorbic acid were added, 40°C reaction for 5 h in the dark; 1M hydrochloric acid was added to adjust the pH to 5, 40°C rotary evaporation for 5 h, the residue was dissolved with 1000 ml anhydrous ethanol / water (anhydrous ethanol and water in a volume ratio of 1:14), deionized water containing 0.1 wt% ascorbic acid was used for dialysis (molecular weight cut-off 1000 Da) for 72 h (every 6 hours, 2000 ml was replaced each time), -50°C freeze-drying for 24 h, to obtain the modified toughening agent.

[0045] Example 4: Preparation of antibacterial agent

[0046] N1: under nitrogen protection, 10 g polydopamine was mixed with 150 ml anhydrous DMF, 2.1 g triethylamine was added, stirred and mixed, then 4.6 g 4-aminosulfonyl benzoyl chloride (added in 4 batches, each batch interval 10 min) was added, 30°C reaction for 7 h in the dark; 500 ml deionized water was added and stirred to precipitate, 8000 rpm centrifugation for 10 min, washed with anhydrous ethanol 3 times (50 ml each time), 40°C vacuum drying for 8 h, to obtain intermediate A; the reaction equation is as follows:

[0047]

[0048] ​N2: Under nitrogen protection, 300 ml of anhydrous DMF, 26 g of gallic acid were stirred and mixed under ice bath; 35 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 21 g of N-hydroxysuccinimide were weighed and mixed, and then added into the gallic acid DMF solution in 5 batches (with 5 min interval), and stirred and activated under ice bath for 45 min; at room temperature, 100 g of intermediate A was added into 500 ml of anhydrous DMF, and ultrasonically dispersed for 10 min under nitrogen protection, and then 200 ml of PBS buffer solution (the concentration of PBS buffer solution was 0.1 M, and the pH was 7.4) was added, and stirred and mixed, and then the activated gallic acid DMF solution was slowly added dropwise under light shielding condition, and after dropwise addition for 1 h, 25°C light shielding reaction was performed for 9 h (during the reaction process, 0.1 M HCl / NaOH solution was used to maintain the pH of the solution between 7.2-7.6); after the reaction was completed, the mixture was loaded into a dialysis bag with a molecular weight cut-off of 8000 Da, and dialyzed with deionized water for 72 h (every 6 h, 2000 ml of water was replaced), and then freeze-dried at -50°C for 24 h to obtain the antibacterial agent; the reaction equation is shown as follows:

[0049]

[0050] Example 5: Preparation of antibacterial agent

[0051] N1: Under nitrogen protection, 10 g of polydopamine was mixed with 150 ml of anhydrous DMF, 2.2 g of triethylamine was added, and stirred and mixed, and then 4.9 g of 4-aminosulfonyl benzoyl chloride was added in 4 batches (with 10 min interval), and 35°C light shielding reaction was performed for 6 h; 500 ml of deionized water was added and stirred to precipitate, and then centrifuged at 8000 rpm for 10 min, and washed with anhydrous ethanol for 3 times (50 ml each time), and then vacuum dried at 40°C for 8 h to obtain intermediate A;

[0052] N2: Under nitrogen protection, 300 ml of anhydrous DMF, 26 g of gallic acid were stirred and mixed under ice bath;

[0053] N2: Under nitrogen protection, 300 ml of anhydrous DMF and 27 g of gallic acid were stirred and mixed in an ice bath; 35 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 21 g of N-hydroxysuccinimide were weighed and added to the gallic acid DMF solution in 5 batches (5 min interval between each batch), and stirred and activated in an ice bath for 45 min; at room temperature, 100 g of intermediate A was added to 500 ml of anhydrous DMF, ultrasonically dispersed for 10 min under nitrogen protection, then 200 ml of PBS buffer (PBS buffer concentration is 0.1 M, pH is 7.4) was added, stirred and mixed, slowly added the activated gallic acid DMF solution under light-proof condition, after 1 h of dropwise addition, 30°C light-proof reaction for 7 h (the solution pH was maintained at 7.2-7.6 by 0.1 M HCl / NaOH solution during the reaction); after the reaction was completed, the mixture was loaded into a dialysis bag with a molecular weight cut-off of 8000 Da, dialyzed with deionized water for 72 h (water was changed every 6 hours, 2000 ml each time), freeze-dried at -50°C for 24 h, to obtain the antibacterial agent.

[0054] Example 6 Preparation of antibacterial agent:

[0055] N1: Under nitrogen protection, 10 g of polydopamine was mixed with 150 ml of anhydrous DMF, 2.3 g of triethylamine was added and stirred and mixed, then 5.1 g of 4-aminosulfonyl benzoyl chloride was added in 4 batches (10 min interval between each batch), 35°C light-proof reaction for 5 h; 500 ml of deionized water was added and stirred to precipitate, centrifuged at 8000 rpm for 10 min, washed with anhydrous ethanol 3 times (50 ml each time), vacuum dried at 40°C for 8 h, to obtain intermediate A;

[0056] N2: Under nitrogen protection, 300 ml of anhydrous DMF and 27 g of gallic acid were stirred and mixed in an ice bath; 35 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 21 g of N-hydroxysuccinimide were weighed and added to the gallic acid DMF solution in 5 batches (5 min interval between each batch), and stirred and activated in an ice bath for 45 min; at room temperature, 100 g of intermediate A was added to 500 ml of anhydrous DMF, ultrasonically dispersed for 10 min under nitrogen protection, then 200 ml of PBS buffer (PBS buffer concentration is 0.1 M, pH is 7.4) was added, stirred and mixed, slowly added the activated gallic acid DMF solution under light-proof condition, after 1 h of dropwise addition, 30°C light-proof reaction for 7 h (the solution pH was maintained at 7.2-7.6 by 0.1 M HCl / NaOH solution during the reaction); after the reaction was completed, the mixture was loaded into a dialysis bag with a molecular weight cut-off of 8000 Da, dialyzed with deionized water for 72 h (water was changed every 6 hours, 2000 ml each time), freeze-dried at -50°C for 24 h, to obtain the antibacterial agent.

[0057] Example 7 Preparation of bone cement for orthopedic repair:

[0058] (1) Weigh by weight: composite calcium phosphate salt 55 g (38.5 g of α-tricalcium phosphate and 16.5 g of β-tricalcium phosphate), bioactive glass 10 g, developer (tantalum powder) 2 g, hydroxyapatite 1 g, modified toughening agent (prepared in Example 1) 8 g, nanocellulose fiber (bacterial cellulose) 2 g, sodium alginate solution (2 wt%) 40 g, methacrylated gelatin 10 g, transglutaminase 0.5 g, citric acid buffer (0.1 M, pH = 6.5) 30 g, antibacterial agent (prepared in Example 4) 1 g;

[0059] (2) First, the nanocellulose fiber is placed in a freeze dryer, and dried at -50°C for 12 h to obtain dried nanocellulose fiber. Then, the composite calcium phosphate salt, bioactive glass, developer, hydroxyapatite, dried nanocellulose fiber and modified toughening agent are mixed in a three-dimensional mixer at 60 rpm for 2 h to obtain a solid-phase powder;

[0060] (3) Mix the methacrylated gelatin with the citric acid buffer (0.1 M, pH = 6.5), stir and mix uniformly in a 60°C water bath, and cool to room temperature in the dark. Add the transglutaminase and the antibacterial agent to the 2 wt% sodium alginate solution, and ultrasonically disperse for 5 min at 20 kHz. Mix the above two solutions under light-proof conditions, and magnetically stir at 500 rpm for 10 min to obtain a liquid-phase component;

[0061] (4) Mix the solid-phase powder and the liquid-phase component according to a mass ratio of 3:1, and stir for 5 min to obtain a bone cement for orthopedic repair.

[0062] Example 8 Preparation of a bone cement for orthopedic repair:

[0063] (1) Weigh by weight: composite calcium phosphate salt 55 g (38.5 g of α-tricalcium phosphate and 16.5 g of β-tricalcium phosphate), bioactive glass 10 g, developer (tantalum powder) 2 g, hydroxyapatite 1 g, modified toughening agent (prepared in Example 1) 8 g, nanocellulose fiber (bacterial cellulose) 2 g, sodium alginate solution (2 wt%) 40 g, methacrylated gelatin 10 g, transglutaminase 0.5 g, citric acid buffer (0.1 M, pH = 6.5) 30 g, antibacterial agent (prepared in Example 4) 1 g;

[0064] (2) First, the nanocellulose fiber is placed in a freeze dryer, and dried at -50°C for 12 h to obtain dried nanocellulose fiber. Then, the composite calcium phosphate salt, bioactive glass, developer, hydroxyapatite, dried nanocellulose fiber and modified toughening agent are mixed in a three-dimensional mixer at 60 rpm for 2 h to obtain a solid-phase powder;

[0065] (3) mixing the methacrylated gelatin with the citric acid buffer (0.1 M, pH = 6.5), stirring uniformly in a water bath at 60°C, cooling to room temperature in the dark; adding the transglutaminase and the antibacterial agent into the sodium alginate solution with a concentration of 2 wt%, ultrasonic dispersion for 5 min at 20 kHz; mixing the above two solutions under the condition of avoiding light, magnetic stirring for 10 min at 500 rpm, to obtain the liquid phase component;

[0066] (4) mixing the solid phase powder and the liquid phase component uniformly according to the mass ratio of 3:1, stirring for 5 min, to obtain the bone cement for orthopedic repair.

[0067] Example 9: Preparation of bone cement for orthopedic repair

[0068] (1) weighing according to the weight: composite calcium phosphate salt 65 g (45.5 g of α-tricalcium phosphate and 19.5 g of β-tricalcium phosphate), bioactive glass 15 g, developing agent (tantalum powder) 3 g, hydroxyapatite 2 g, modified toughening agent (prepared in Example 3) 12 g, nanocellulose fiber (bacterial cellulose) 3 g, sodium alginate solution (2 wt%) 50 g, methacrylated gelatin 20 g, transglutaminase 1 g, citric acid buffer (0.1 M, pH = 6.5) 60 g, antibacterial agent (prepared in Example 6) 2 g;

[0069] (2) first, the nanocellulose fiber is placed in a freeze dryer, and dried at -50°C for 12 h to obtain dried nanocellulose fiber, then the composite calcium phosphate salt, bioactive glass, developing agent, hydroxyapatite, dried nanocellulose fiber and modified toughening agent are mixed in a three-dimensional mixer at 60 rpm for 2 h to obtain a solid phase powder;

[0070] (3) mixing the methacrylated gelatin with the citric acid buffer (0.1 M, pH = 6.5), stirring uniformly in a water bath at 60°C, cooling to room temperature in the dark; adding the transglutaminase and the antibacterial agent into the sodium alginate solution with a concentration of 2 wt%, ultrasonic dispersion for 5 min at 20 kHz; mixing the above two solutions under the condition of avoiding light, magnetic stirring for 10 min at 500 rpm, to obtain the liquid phase component;

[0071] (4) mixing the solid phase powder and the liquid phase component uniformly according to the mass ratio of 3:1, stirring for 5 min, to obtain the bone cement for orthopedic repair.

[0072] Comparative Example 1

[0073] The raw material composition and preparation method of the bone cement for orthopedic repair are basically the same as those of Example 8, except that no modified toughening agent is added in the composition.

[0074] Comparative Example 2

[0075] The raw material composition and the preparation method of the bone cement for orthopedic repair are basically the same as those in Example 8, except that no antibacterial agent is added in the composition.

[0076] Comparative Example 3

[0077] The raw material composition and the preparation method of the bone cement for orthopedic repair are basically the same as those in Example 8, except that the modified toughening agent is replaced by an equal weight of a modified toughening agent prepared by the following method:

[0078] The preparation method of the modified toughening agent is basically the same as that in Example 2, except that 12-oxododecanoic acid in step S1 is replaced by an equal molar amount of 5-oxopentanoic acid.

[0079] Comparative Example 4

[0080] The raw material composition and the preparation method of the bone cement for orthopedic repair are basically the same as those in Example 8, except that the modified toughening agent is replaced by an equal weight of a modified toughening agent prepared by the following method:

[0081] The preparation method of the modified toughening agent is basically the same as that in Example 2, except that dopamine in step S2 is replaced by an equal molar amount of p-hydroxyphenethylamine.

[0082] Comparative Example 5

[0083] The raw material composition and the preparation method of the bone cement for orthopedic repair are basically the same as those in Example 8, except that the modified toughening agent is replaced by an equal weight of a modified toughening agent prepared by the following method:

[0084] The preparation method of the modified toughening agent is basically the same as that in Example 2, except that the amount of dopamine added in step S2 is reduced to 0.2 mol.

[0085] Comparative Example 6

[0086] The raw material composition and the preparation method of the bone cement for orthopedic repair are basically the same as those in Example 8, except that the antibacterial agent is replaced by an equal weight of an antibacterial agent prepared by the following method:

[0087] The preparation method of the antibacterial agent is basically the same as that in Example 5, except that 4-aminosulfonyl benzoyl chloride in step N1 is replaced by an equal weight of 4-aminobenzoyl chloride.

[0088] Comparative Example 7

[0089] The raw material composition and the preparation method of the bone cement for orthopedic repair are basically the same as those in Example 8, except that the antibacterial agent is replaced by an equal weight of an antibacterial agent prepared by the following method:

[0090] The preparation method of the antibacterial agent is basically the same as that in Embodiment 5, except that gallic acid in step N2 is replaced by equal weight of p-hydroxybenzoic acid.

[0091] The tantalum powder used in the examples and comparative examples of the present application is Model ML-Ta-N50, produced by Zhejiang Manlin Nanometer Technology Co., Ltd.; the bacterial cellulose is bacterial cellulose dispersion TL-008, produced by Nanjing Tianlu Nanometer Technology Co., Ltd.; the bioactive glass is Model HQ-BG45s-D1, produced by Kunshan Huagiao Science and Technology New Material Co., Ltd.; the hydroxyapatite is Model HAP03-20, produced by Nanjing Junzhu Biological Technology Co., Ltd.; the methacrylated gelatin is EFL-GM-60; the sodium alginate is medical grade, with a viscosity of 600 mPa·s, produced by Qingdao Mingyue Marine New Material Technology Co., Ltd.; the polydopamine has a number average molecular weight of 1000 Da. The CAS number of 4-aminosulfonylbenzoyl chloride is 51594-97-9.

[0092] The bone cements prepared in Examples 7-9 and Comparative Examples 1-7 were subjected to compression strength, bending strength and antibacterial performance tests. The test results are shown in Table 1.

[0093] The compression strength and bending strength of the bone cements were tested according to the YY 0459-2003 standard. The compression strength test was performed using a universal testing machine at a loading speed of 20 mm / min, and the bending strength test was performed at a loading speed of 5 mm / min. The test samples were kept at 23°C for 24 h before testing.

[0094] Bending test sample preparation: 100 g of the bone cement prepared in the comparative examples and examples was poured into a polytetrafluoroethylene mold, and cured at 37°C for 1 h to obtain the test sample (the test sample size is 75 mm long, 10 mm wide and 3.3 mm deep).

[0095] Compression test sample preparation: 100 g of the bone cement prepared in the comparative examples and examples was poured into a polytetrafluoroethylene cylindrical mold, and cured at 37°C for 1 h to obtain the test sample (the test sample size is 6 mm in diameter and 12 mm long).

[0096] Sample damage repair test: a knife was used to make a damage cut (0.5 mm deep and 10 mm long) at the center of the gauge section of the sample, and then the sample was immersed in 50 ml of PBS buffer solution at 37°C, 0.1M and pH=7.4. After soaking for 24 h, the repaired bone cement was obtained.

[0097] The bacteriostatic effect of the bone cement is tested by means of a bacteriostatic ring. Staphylococcus aureus is selected as the test target strain. The freeze-dried powder of the strain is mixed with a recovery solution to prepare a bacterial suspension for subculture. The bacterial suspension is inoculated on a slope culture medium by means of an inoculation ring, and cultured for 24 h. Then, the second-generation colonies are inoculated on a flat plate culture medium and cultured for 24 h to obtain a second-generation bacterial suspension with a concentration of 10 8 CFU / ml. The bone cement is prepared into a small piece with a diameter of 10 mm and a thickness of 1 mm. The sample is soaked in normal saline, and the excess normal saline is shaken off. The bone cement sample is attached to a microbial-coated MH culture plate, and the culture plate is placed in a constant-temperature incubator at 37°C and cultured for 24 h. After the culture plate is taken out, optical photography is performed, and whether an obvious bacteriostatic ring appears around the bone cement sample is observed. The diameter of the bacteriostatic ring is measured by means of measurement.

[0098] Table 1

[0099]

[0100] As can be seen from Table 1, the bone cement prepared in Examples 7-9 has excellent mechanical properties, self-repairing properties and antibacterial properties.

[0101] Comparative Examples 1 and 2 are comparative examples without adding the modified toughening agent and the antibacterial agent, respectively. The compressive strength, bending strength and self-repairing properties of the bone cement prepared in Comparative Example 1 and the antibacterial properties of the bone cement prepared in Comparative Example 2 are obviously lower than those of the examples, which further reflects that the modified toughening agent and the antibacterial agent prepared in the application can synergistically improve the mechanical properties, self-repairing properties and antibacterial properties of the bone cement.

[0102] The compressive strength and bending strength of the bone cement prepared in Comparative Examples 3 and 4 are lower than those of the examples. This is mainly because the chain of 5-oxovaleric acid used in Comparative Example 3 is shorter than that of 12-oxododecanoic acid, resulting in a decrease in the flexibility and an increase in the rigidity of the modified toughening agent. The molecular chain cannot dissipate energy through chain segment motion, resulting in an increase in brittleness of the bone cement under external force. The p-hydroxyphenethylamine used in Comparative Example 4 has only a single phenolic hydroxyl group, and the ortho-catechol group is missing, resulting in a decrease in the interfacial bonding chemical anchoring ability of the modified toughening agent and the bone cement matrix, a decrease in stress transfer, and thus a decrease in the compressive strength of the bone cement. The modified toughening agent Schiff base used in Comparative Example 5 has a small amount, and the broken compressive strength is low.

[0103] The antibacterial performance of the bone cement prepared in Comparative Example 6 is reduced compared with the examples, mainly because the antibacterial agent prepared using 4-aminobenzoyl chloride lacks a sulfonyl group. The rigid structure of the benzene ring and the sulfonyl group causes the grafted gallic acid molecules to be perpendicular to the surface of the polydopamine, and the phenolic hydroxyl groups are fully exposed. The phenolic hydroxyl groups can play a high-efficiency antibacterial role by destroying bacterial cell membranes and inhibiting enzyme activity. The lack of a sulfonyl group reduces the grafting rate of gallic acid and the insufficient exposure of the gallic acid reduces the antibacterial performance of the bone cement.

[0104] The antibacterial performance of the bone cement prepared in Comparative Example 7 is reduced compared with the examples, mainly because the p-hydroxybenzoic acid used to prepare the antibacterial agent lacks the multiple ortho-phenolic hydroxyl groups of gallic acid. This results in a sharp reduction in the number of active sites of the antibacterial groups, a loss of the ability to destroy bacterial cell membranes, and a loss of the enzyme inhibition function. Ultimately, the antibacterial agent cannot effectively kill bacteria, and this significantly reduces the antibacterial performance of the bone cement.

[0105] The above is only a preferred embodiment of the present application and is not intended to limit the present application. For those of ordinary skill in the art, some minor changes, modifications, and equivalent variations of the above disclosed technical content can be made without departing from the scope of the technical solutions of the present application. All equivalent embodiments made by such changes, modifications, and variations are equivalent embodiments of the present application. Furthermore, any equivalent changes, modifications, and variations made to the above examples according to the essential technical spirit of the present application are still within the scope of the technical solutions of the present application.

Claims

1. A bone cement for orthopedic repair, characterized in that, Includes solid powder and liquid components; The solid powder comprises the following components in parts by weight: 55-65 parts of composite calcium phosphate, 10-15 parts of bioactive glass, 2-3 parts of developer, 1-2 parts of hydroxyapatite, 8-12 parts of modified toughening agent, and 2-3 parts of nanocellulose fiber. The liquid phase component comprises the following components in parts by weight: 40-50 parts sodium alginate solution, 10-20 parts methacrylamide gelatin, 0.5-1 part transglutaminase, 30-60 parts citrate buffer, and 1-2 parts antibacterial agent. The modified toughening agent is prepared by the following method: S1: Under nitrogen protection, pentaerythritol, 12-oxododecanoic acid and anhydrous toluene were mixed, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 4-dimethylaminopyridine were added. The mixture was reacted at 80-100℃ for 6-8 h to obtain intermediate 1. S2: Under nitrogen protection, intermediate 1, dopamine and anhydrous ethanol are mixed, triethylamine and ascorbic acid are added, and the mixture is reacted at 30-40℃ for 5-7 hours to obtain the modified toughening agent.

2. The bone cement for orthopedic repair according to claim 1, characterized in that, In step S1, the molar ratio of pentaerythritol to 12-oxododecanoic acid is 1:(4.1-4.3).

3. The bone cement for orthopedic repair according to claim 1, characterized in that, In step S2, the molar ratio of intermediate 1 to dopamine is 1:(4.05-4.2).

4. The bone cement for orthopedic repair according to claim 1, characterized in that, The antibacterial agent is prepared by the following method: N1: Under nitrogen protection, polydopamine and anhydrous DMF were mixed evenly, triethylamine was added and mixed evenly, and then 4-aminosulfonylbenzoyl chloride was added. The mixture was reacted at 30-40℃ for 5-7 hours to obtain intermediate A. N2: Under nitrogen protection, gallic acid and anhydrous DMF are mixed, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide are added for activation; then the mixture is slowly added to the PBS buffer of intermediate A and reacted at 25-30℃ for 7-9 hours to obtain the antibacterial agent.

5. The bone cement for orthopedic repair according to claim 4, characterized in that, In step N1, the mass ratio of polydopamine to 4-aminosulfonylbenzoyl chloride is 1:(0.46-0.51).

6. The bone cement for orthopedic repair according to claim 4, characterized in that, In step N2, the mass ratio of intermediate A to gallic acid is 1:(0.25-0.27).

7. The bone cement for orthopedic repair according to claim 1, characterized in that, The composite calcium phosphate salt includes α-tricalcium phosphate and β-tricalcium phosphate, wherein α-tricalcium phosphate accounts for 70% by weight and β-tricalcium phosphate accounts for 30% by weight; the developer is tantalum powder; and the nanocellulose fiber is bacterial cellulose.

8. The bone cement for orthopedic repair according to claim 1, characterized in that, The sodium alginate solution has a concentration of 2 wt%; the citrate buffer solution has a concentration of 0.1 M and a pH of 6.

5.

9. A method for preparing bone cement for orthopedic repair according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Weigh out the following by weight: 55-65 parts of compound calcium phosphate, 10-15 parts of bioactive glass, 2-3 parts of developer, 1-2 parts of hydroxyapatite, 8-12 parts of modified toughening agent, 2-3 parts of nanocellulose fiber, 40-50 parts of sodium alginate solution, 10-20 parts of methacrylamide gelatin, 0.5-1 part of transglutaminase, 30-60 parts of citrate buffer, and 1-2 parts of antibacterial agent; (2) First, freeze-dry the nanocellulose fibers to obtain dried nanocellulose fibers. Then, mix the composite calcium phosphate salt, bioactive glass, developer, hydroxyapatite, dried nanocellulose fibers and modified toughening agent in a three-dimensional mixer to obtain solid powder. (3) Mix methacrylamide gelatin with citrate buffer, stir and mix well in a 60°C water bath, and cool to room temperature in the dark; add transglutaminase and antibacterial agent to sodium alginate solution and disperse by sonication; Under light-protected conditions, the two solutions were mixed and stirred to obtain the liquid phase component; (4) Mix the solid powder and liquid components at a mass ratio of 3:1 and stir to obtain bone cement for orthopedic repair.

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