Isobornyl acrylate modified antibacterial bone cement

Abstract

The invention belongs to the field of biomedical materials, and discloses isobornyl acrylate modified antibacterial bone cement. Isobornyl acrylate (BA) serves as a novel monomer and is used for liquid phase modification of bone cement, BA modified antibacterial bone cement (BA bone cement) is finally prepared, the BA modified antibacterial bone cement is novel antibacterial NLBC and is good in antibacterial activity, compressive strength and biocompatibility, and the excellent performance of the BA modified antibacterial bone cement shows that the BA modified antibacterial bone cement has wide prospects in clinical application.

Description

Technical Field

[0001] The invention relates to the field of biomedical materials, and in particular to an antibacterial bone cement modified with isobornyl acrylate. Background Art

[0002] As a commonly used biomedical material, polymethyl methacrylate (PMMA) bone cement is widely used in surgical procedures such as joint replacement and vertebroplasty. However, its insufficient antibacterial activity has always been a concern. Staphylococcus aureus is the most common pathogen in orthopedics, which may cause postoperative infection, delayed healing and even surgical failure, seriously affecting the patient's prognosis and quality of life. To meet this severe challenge, the traditional improvement method is to mix antibiotics into bone cement to make antibiotic-loaded bone cement (ALBC). Since Buchholz first added antibiotics to bone cement in 1969, research on antibiotic-loaded bone cement (ALBC) has attracted widespread attention. However, this method has problems such as explosive release of antibiotics and bacterial resistance, which limits its further use in clinical applications. In this context, the research and development of new antibacterial bone cement has become one of the hot topics in the field of orthopedics.

[0003] Non-leaching antibacterial bone cement (NLBC) fixes groups with antibacterial activity on bone cement by covalent bonding or physical adsorption, thereby preparing modified bone cement with long-term antibacterial activity and good contact bactericidal activity. However, there is currently no NLBC with excellent antibacterial activity, mechanical strength and biocompatibility. Usually, compromises need to be made in other aspects to give priority to a certain performance, which limits the further research and application of NLBC. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned background technology and provide an antibacterial bone cement modified with isobornyl acrylate. The present invention uses isobornyl acrylate (BA) as a new monomer for liquid phase modification of bone cement, and finally prepares a BA-modified antibacterial bone cement (BA bone cement), which is a new type of antibacterial NLBC with excellent antibacterial activity, compressive strength and biocompatibility. Its excellent performance shows that it has broad prospects in clinical applications.

[0005] To achieve the purpose of the present invention, the antibacterial bone cement modified with isobornyl acrylate of the present invention is obtained by adding isobornyl acrylate into bone cement.

[0006] Furthermore, in some embodiments of the present invention, the bone cement is polymethyl methacrylate (PMMA) bone cement.

[0007] Furthermore, in some embodiments of the present invention, the polymethyl methacrylate bone cement comprises a solid phase and a liquid phase, and the mass ratio of the solid phase to the liquid phase is 1.5-2.5:1.

[0008] Furthermore, in some embodiments of the present invention, the mass ratio of the solid phase to the liquid phase in the polymethyl methacrylate bone cement is 1.6-2.2:1.

[0009] Furthermore, in some embodiments of the present invention, the mass ratio of the solid phase to the liquid phase in the polymethyl methacrylate bone cement is 1.65-2.05:1.

[0010] Furthermore, in some embodiments of the present invention, the concentration of isobornyl acrylate in the bone cement is greater than or equal to 10.0%, for example, greater than or equal to 15.0%, and for example, greater than or equal to 20.0%, preferably greater than or equal to 25.0%, and more preferably greater than or equal to 30.0%, wherein the concentration of isobornyl acrylate in the bone cement is calculated according to the mass proportion of isobornyl acrylate in the liquid phase of the bone cement.

[0011] Furthermore, in some embodiments of the present invention, the specific steps of adding isobornyl acrylate to bone cement are as follows: adding isobornyl acrylate to the liquid phase of bone cement, and then mixing it evenly with the solid phase of bone cement to prepare a bone cement sample.

[0012] Isobornyl acrylate (BA) is a liquid that is easily soluble in MMA. The present invention reports for the first time a non-leaching antibacterial bone cement (BA bone cement) modified with isobornyl acrylate (BA). This bone cement has excellent antibacterial activity and mechanical strength, and its compressive strength meets the ISO5833 standard. It has no hemolytic activity and low in vitro cytotoxicity, and has good application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The figures are the mechanical strength test results of the BA bone cement of the present invention, wherein Figure A is a stress-strain diagram, in which the slope represents the elastic modulus and the parallel lines represent the compressive strength; Figure B is a statistical histogram of the compressive strength data; and Figure C is a histogram of the elastic modulus data. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be understood through the practice of the present invention. It should be understood that the following description is only used to explain the present invention and is not intended to limit the present invention.

[0015] When amount, concentration or other value or parameter is expressed as range, preferred range or a series of upper preferred value and lower preferred value limit range, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when disclosing range "1 to 5", described range should be interpreted as including range "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc. When numerical range is described in this article, unless otherwise stated, the range is intended to include its end value and all integers and fractions within the range.

[0016] The indefinite articles "a" and "an" before the elements or components of the present invention have no limitation on the quantity requirements (i.e. the number of occurrences) of the elements or components. Therefore, "a" or "an" should be interpreted as including one or at least one, and the elements or components in the singular form also include the plural form, unless the quantity obviously refers to the singular form only.

[0017] In addition, the descriptions of the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" described below mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0018] In the present invention, isobornyl acrylate (BA) is a commercially available reagent, and its structure is shown below:

[0019]

[0020] Example 1

[0021] The preparation method of BA bone cement is as follows: The formula and grouping of bone cement are shown in Table 1. 10wt% and 30wt% represent the mass ratio of antibacterial monomer BA added to the liquid phase agent. Commercially available PMMA bone cement without any antibacterial monomer added is used as a blank control group. The polymethyl methacrylate (PMMA) bone cement involved in the present invention can be selected from the commercially available Eurofix brand, including a solid phase and a liquid phase, and the solid-liquid ratio is about 2:1.

[0022] Table 1 Antibacterial bone cement modified with isobornyl acrylate in different ratios

[0023]

[0024] Preparation of standard bone cement samples: According to Table 1, the antibacterial monomer BA was mixed into the liquid phase in the corresponding proportion. The solid phase agent and the liquid phase agent were evenly mixed at room temperature to make a cylindrical bone cement sample. The sample length was 12.0±0.1mm and the diameter was 6.0±0.1mm. The mold was fixed with a woodworking clamp, and the bone cement was taken out after it was completely cured, and polished with sandpaper to control the total mass to 0.40±0.01g to ensure that the top and bottom surfaces of the bone cement were flat. Finally, all samples were sterilized by ethylene oxide.

[0025] Example 2

[0026] BA bone cement antibacterial activity test: BA bone cement samples were immersed in saline at a ratio of 0.1 g / mL at room temperature for 24 hours to remove monomers that did not participate in polymerization on the surface. The samples were then removed, disinfected, and set aside for later use. Staphylococcus aureus (S. aureus) was first revived and passaged to obtain 0.5×10 8 CFU / mL. Then, each group of bone cement samples was placed in a test tube containing 1 mL of the bacterial solution at that concentration. 2 The constant temperature incubator was set to 37 °C and incubated for 6 hours. After the incubation, the sample was slowly rinsed with pure water to remove S. aureus that was not adhered or poorly adhered to the surface of the bone cement. Then, the sample was placed in a test tube containing 5 mL of normal saline and washed with an ultrasonic oscillation cleaner for a controlled time of 2 minutes to remove tightly adhered S. aureus from the surface of the bone cement. After washing, the bone cement sample was removed and the sample solution was thoroughly oscillated. Take 40 μL of the sample solution and dilute it with 0.9% NaCl solution at a ratio of 1:100 for plate coating. Place in a 37 °C CO 2 After incubation in a constant temperature incubator for 24 hours, the number of colonies was counted and the surface antibacterial rate was calculated. The experiment for each group of bone cement samples was repeated five times. The antibacterial rate of PMMA bone cement was set to 0.

[0027]

[0028] The antibacterial activity of the BA bone cement disclosed in the present invention is positively correlated with the content of BA, wherein the antibacterial rate of 10wt% BA bone cement against Staphylococcus aureus is 41.0±10.8%, while the antibacterial rate of 30wt% BA bone cement is 81.0±3.1%, as shown in Table 2 below.

[0029] Table 2 Antibacterial rate of BA bone cement against Staphylococcus aureus

[0030] Bone cement Antibacterial rate PMMA bone cement 0％ 10% BA bone cement 41.0±10.8％ 30% BA bone cement 81.0±3.1％

[0031] Example 3

[0032] The mechanical strength test was performed as follows: bone cement samples (5 per group) were incubated at 37°C and 100% humidity for 24 hours. At room temperature, deformation-load curves of 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 test results are attached. Figure 1 .

[0033] Example 4

[0034] Preparation of bone cement extract: The standard bone cement samples were placed in cell culture medium (DMEM / F12 medium) and saline (0.9% NaCl solution), and the sample-to-liquid ratio was set to 0.2 g / mL according to GB / T 16886 standard. The cell culture medium group was incubated at 37°C and 5% CO 2 The cells were incubated in an incubator for 24 hours, and the saline group was incubated for 30 minutes under the same conditions. The cell culture medium extracts obtained were used for in vitro cytotoxicity assays, while the saline extracts were used for hemolysis assays.

[0035] Hemolysis rate determination: According to GB / T 16886 standard, the bone cement extract was placed in a sterile centrifuge tube and 200 μL of 2% rabbit erythrocyte suspension was added. In addition, 200 μL of 2% rabbit erythrocyte suspension was added to 1.8 mL of saline and pure water as negative and positive controls, respectively. The samples were incubated at 37°C and 5% CO. 2 After incubation in the incubator for 1 hour, centrifuge 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:

[0036]

[0037] 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 following table, a hemolysis rate lower than 5% is considered to be no hemolysis. This indicates that the BA bone cement obtained by the present invention is similar to commercially available bone cement and does not cause hemolysis.

[0038] Table 3 BA bone cement hemolysis rate determination results

[0039] Bone cement Hemolysis rate PMMA bone cement 2.35±1.22％ 10% BA bone cement 2.37±1.24％ 30% BA bone cement 3.13±1.37％

[0040] Those skilled in the art will easily understand that the above descriptions are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An antibacterial bone cement modified with isobornyl acrylate, It is characterized in that The isobornyl acrylate modified antibacterial bone cement is obtained by adding isobornyl acrylate into bone cement.

2. The antibacterial bone cement modified with isobornyl acrylate according to claim 1, It is characterized in that The bone cement is polymethyl methacrylate bone cement.

3. The antibacterial bone cement modified with isobornyl acrylate according to claim 1, It is characterized in that The polymethyl methacrylate bone cement comprises a solid phase and a liquid phase, and the mass ratio of the solid phase to the liquid phase is 1.5-2.5:

1.

4. The antibacterial bone cement modified with isobornyl acrylate according to claim 3, It is characterized in that The mass ratio of the solid phase to the liquid phase in the polymethyl methacrylate bone cement is 1.6-2.2:

1.

5. The antibacterial bone cement modified with isobornyl acrylate according to claim 3, It is characterized in that The mass ratio of the solid phase to the liquid phase in the polymethyl methacrylate bone cement is 1.65-2.05:

1.

6. The antibacterial bone cement modified with isobornyl acrylate according to claim 3, It is characterized in that The concentration of isobornyl acrylate in the bone cement is greater than or equal to 10.0%, and the concentration of isobornyl acrylate in the bone cement is calculated according to the mass proportion of isobornyl acrylate in the liquid phase of the bone cement.

7. The antibacterial bone cement modified with isobornyl acrylate according to claim 3, It is characterized in that The concentration of isobornyl acrylate in the bone cement is greater than or equal to 15.0%, and the concentration of isobornyl acrylate in the bone cement is calculated according to the mass proportion of isobornyl acrylate in the liquid phase of the bone cement.

8. The antibacterial bone cement modified with isobornyl acrylate according to claim 3, It is characterized in that The concentration of isobornyl acrylate in the bone cement is greater than or equal to 20.0%, and the concentration of isobornyl acrylate in the bone cement is calculated according to the mass proportion of isobornyl acrylate in the liquid phase of the bone cement.

9. The antibacterial bone cement modified with isobornyl acrylate according to claim 3, It is characterized in that The concentration of isobornyl acrylate in the bone cement is greater than or equal to 25.0%, preferably greater than or equal to 30.0%, wherein the concentration of isobornyl acrylate in the bone cement is calculated based on the mass ratio of isobornyl acrylate in the liquid phase of the bone cement.

10. The antibacterial bone cement modified with isobornyl acrylate according to claim 1, It is characterized in that The specific steps of adding isobornyl acrylate to bone cement are as follows: adding isobornyl acrylate to the liquid phase of bone cement, and then mixing it evenly with the solid phase of bone cement to prepare a bone cement sample.

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