Antibacterial bone cement and application thereof

Abstract

The invention discloses antibacterial bone cement and application thereof, and belongs to the technical field of medical materials. The antibacterial bone cement comprises a solid phase agent and a liquid phase agent, raw materials of the solid phase agent and / or the liquid phase agent comprise bacteriocin containing an olefin structure. The antibacterial peptide with antibacterial activity is added to obtain the novel bone cement, the novel bone cement has good antibacterial property, mechanical property and biocompatibility, and the problem of explosive release of antibacterial drugs in existing PMMA bone cement is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of medical materials, and in particular relates to an antibacterial bone cement and application thereof. Background Art

[0002] Bone cement is an important medical material in orthopedic treatment and is widely used in bone defect repair, joint prosthesis and other surgeries. Among them, acrylic bone cement, especially polymethyl methacrylate (PMMA) bone cement, has gradually become the gold standard due to its good mechanical properties and injectability. PMMA bone cement is usually composed of a solid phase agent and a liquid phase agent. The solid phase agent contains PMMA powder, developer, initiator, etc., and the liquid phase agent is often composed of methyl methacrylate (MMA), promoter, inhibitor, etc. PMMA bone cement lacks antibacterial activity. In order to prevent postoperative infection, it is urgent to develop antibacterial bone cement.

[0003] Traditional antimicrobial bone cement usually mixes antimicrobial agents, such as antibiotics, into PMMA bone cement to make antibiotic-loaded bone cement (ALBC). Since the mixing of the solid phase agent and the liquid phase agent in the production process of PMMA bone cement is a chemical reaction that will release heat violently, usually only heat-stable antibiotics can be used to make antimicrobial bone cement. The mechanical strength of ALBC obtained after adding antimicrobial agents to bone cement needs to reach 70MPa required by the ISO5833 standard, while many antimicrobial agents, such as bone cement containing isoniazid, have mechanical properties far below 70 MPa. In addition, antibiotics in PMMA bone cement have the defect of explosive release. Therefore, there is an urgent clinical need to develop new bone cements with good mechanical properties and high antimicrobial activity. Summary of the invention

[0004] The present invention aims at the problems of explosive release of antibacterial drugs and poor mechanical strength in existing antibacterial PMMA bone cement, and provides an antibacterial bone cement and its application. The present invention obtains a new bone cement by adding bacteriocin with antibacterial activity, which has good antibacterial property, mechanical property and biocompatibility.

[0005] The invention provides an antimicrobial peptide-containing bone cement, comprising a solid phase agent and a liquid phase agent.

[0006] The raw materials of the solid phase agent and / or the liquid phase agent include antimicrobial peptides, that is, bacteriocins with olefin structures. The olefins in the antimicrobial peptides can participate in polymerization when the solid and liquid phases of bone cement are mixed, thereby fundamentally preventing the explosive release of drugs.

[0007] Furthermore, the bacteriocin containing an olefin structure is Nisin A, and its structure is shown below:

[0008] .

[0009] Furthermore, the solid phase agent is a commercially available bone cement solid phase agent, or a composite composed of the following compounds: PMMA powder, benzoyl peroxide, barium sulfate or zirconium dioxide.

[0010] The liquid phase agent is a commercially available bone cement liquid phase agent, or a complex composed of the following compounds: methyl methacrylate, dimethyl paratoluidine, etc.

[0011] Furthermore, the components are composed of the following by mass:

[0012] Solid phase agent: PMMA powder 70-90 parts, barium sulfate or zirconium dioxide 10-40 parts, benzoyl peroxide 0.1-5 parts;

[0013] Liquid phase agent: 10-95 parts of methyl methacrylate, 0.1-5 parts of dimethyl p-toluidine.

[0014] And 0.5-25 parts of bacteriocin containing olefin structure is compounded and added into the solid phase agent and / or the liquid phase agent.

[0015] Furthermore, the added mass fraction of the bacteriocin containing an olefin structure is 2.5-10 parts.

[0016] Furthermore, the mass fraction of the bacteriocin containing an olefin structure added is 2.5-5 parts.

[0017] The solid phase agent and the liquid phase agent are usually mixed in a mass ratio of 2:1 to form bone cement.

[0018] Application of the antibacterial bone cement of the present invention in preparing bone repair materials.

[0019] The bone cement of the invention has good antibacterial activity, mechanical properties and biocompatibility.

[0020] The beneficial effects of the present invention are embodied in:

[0021] (1) Compared with the existing technology, the present invention adds olefin-containing bacteriocin, avoids the use of antibiotics, and avoids explosive release.

[0022] (2) The bone cement obtained by using the new antibacterial monomer has good antibacterial properties, in addition to good mechanical properties and biocompatibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The bone cement powder prepared in the example table was thoroughly mixed with potassium bromide at a ratio of about 1:50, ground and pressed into tablets. The prepared samples were analyzed using a Fourier transform infrared spectrometer (FT-IR).

[0024] Figure 2 It is the test data of mechanical strength of bone cement.

[0025] Figure 3 It is the antibacterial rate test data. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is described below in conjunction with the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, but not all of them.

[0027] Nisin A used in the examples was commercially available.

[0028] Example:

[0029] Bone cement includes a solid phase agent and a liquid phase agent, and its composition is shown in the following table:

[0030]

[0031] Preparation method of antibacterial bone cement: The solid phase agent and the liquid phase agent are mixed according to the ratio in the above table, and formed into a cylinder with a height of 12 mm and a diameter of 6 mm in a mold. 1 in the table is conventional PMMA bone cement, and 2, 3, and 4 are antibacterial bone cements with the addition amount of the new antibacterial monomer being 2.5%, 5%, and 10% of the mass of the solid phase agent, respectively.

[0032] Figure 1 The bone cement powder prepared in the example table was thoroughly mixed with potassium bromide at a ratio of about 1:50, ground and pressed into tablets. The prepared samples were analyzed using a Fourier transform infrared spectrometer (FT-IR).

[0033] The mechanical strength test was performed as follows: The bone cement samples (5 per group) were polished with 1000-grit sandpaper until the top and bottom surfaces were parallel. The samples were incubated at 37°C and 100% humidity for 24 hours. At room temperature, the deformation-load curves of the bone cement samples were plotted using a material testing machine (MTS809, Bose Corporation, USA) at a loading rate of 20 mm / min. The compressive strength and elastic modulus of each bone cement sample were calculated from these curves. All operations were performed in accordance with the requirements and standards of ISO 5833. The results are shown in Figure 2 .

[0034] The antibacterial activity of Nisin A was evaluated as follows: Staphylococcus aureus (ACTT 25923) was revived and passaged to restore its activity. Bone cement samples were synthesized the day before the experiment and soaked in 3 mL of distilled water for 18 h to remove unpolymerized Nisin A monomers on the surface. On the day of the experiment, a bacterial suspension with a concentration of (0.5 × 108) CFU / mL was prepared. Each bone cement sample was soaked in 1 mL of the bacterial suspension and incubated at 37 °C in a CO2 incubator for 6 h. The sample was then removed and gently rinsed with 100 mL of distilled water to remove non-adherent bacteria. The sample was placed in 5 mL of saline and sonicated for 3 min to remove adherent bacteria. Subsequently, the bone cement sample was removed, and the remaining liquid was retained, 40 μL was aspirated from it and diluted 100 times, and after thorough mixing, 40 μL was aspirated from the diluted bacterial solution and evenly spread on the culture dish. The culture dishes were incubated in a CO2 incubator at 37°C for one day, and colony counts were performed to calculate the surface inhibition rate of bone cement containing different concentrations of Nisin A. Each concentration of bone cement was tested five times.

[0035]

[0036] In the above antibacterial rate calculation formula, A represents the number of colonies on the culture dish of the control group bone cement, and B represents the number of colonies on the culture dish of the different concentrations of Nisin A bone cement groups. Figure 3 .

[0037] Hemolysis rate determination: According to GB / T 16886 standard (State Administration of Market Supervision of China, 2022), the bone cement extract was placed in a sterile centrifuge tube and 200 μL of 2% rabbit red blood cell suspension was added. In addition, 200 μL of 2% rabbit red blood cell suspension was added to 1.8 mL of normal saline and pure water as negative and positive controls, respectively. After incubation in a 37°C, 5% CO2 incubator for 1 hour, centrifugation was performed at 3000 rpm for 5 minutes. The optical density (OD) of the supernatant was measured at 545 nm using a spectrophotometer. Hemolysis was assessed by visual inspection of the clarity of the supernatant. Each group of bone cement samples was tested three times. The hemolysis rate (HR) was calculated using the following formula:

[0038]

[0039] Among them, OD T1 is the optical density of the experimental solution, OD N1 is the optical density of the negative control, OD P is the optical density of the positive control. As shown in the table below, a hemolysis rate of less than 5% is considered to be no hemolysis. This shows that Nisin A bone cement is similar to commercially available bone cement and does not cause hemolysis.

[0040]

Claims

1. An antibacterial bone cement, characterized in that: The antibacterial bone cement comprises a solid phase agent and a liquid phase agent; The raw materials of the solid phase agent and / or the liquid phase agent include antimicrobial peptides, and the antimicrobial peptides are bacteriocins containing olefin structures.

2. The antibacterial bone cement according to claim 1, characterized in that: The bacteriocin containing an olefin structure is Nisin A, and its structure is shown below: 。 3. The antibacterial bone cement according to claim 1, characterized in that: The solid phase agent is a commercially available bone cement solid phase agent, or is composed of raw materials including the following components: PMMA powder, benzoyl peroxide, barium sulfate or zirconium dioxide; The liquid phase agent is a commercially available bone cement liquid phase agent, or is composed of raw materials including the following components: methyl methacrylate, dimethyl paratoluidine; And the bacteriocin containing olefin structure is compounded and added into the solid phase agent and / or the liquid phase agent.

4. The antibacterial bone cement according to claim 3, characterized in that The components are composed by mass: Solid phase agent: PMMA powder 70-90 parts, barium sulfate or zirconium dioxide 10-40 parts, benzoyl peroxide 0.1-5 parts; Liquid phase agent: 10-95 parts of methyl methacrylate, 0.1-5 parts of dimethyl p-toluidine; 0.5-25 parts of bacteriocin containing olefin structure.

5. The antibacterial bone cement according to claim 4, characterized in that: The mass fraction of the bacteriocin containing an olefin structure is 2.5-10 parts.

6. The antibacterial bone cement according to claim 5, characterized in that: The mass fraction of the bacteriocin containing an olefin structure is 2.5-5 parts.

7. Use of the antibacterial bone cement according to any one of claims 1 to 6 in the preparation of bone repair materials.

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