Calcium-titanium octahedron with photosensitive antibacterial property as well as preparation method and application of calcium-titanium octahedron

Abstract

The invention discloses a calcium-titanium octahedral bone defect repair composite material with photosensitive antibacterial property and a preparation method thereof. By inhibiting the activity of pathogenic microorganisms, the microcosmic-macroscopic structure in the bone is reconstructed, the microenvironment ion-structure disorder is corrected, and the regeneration of the infectious bone defect is promoted. The calcium-titanium octahedral composite material has a unique photocatalytic effect, and can effectively inhibit the growth of bacteria under the catalysis of blue light with the wavelength of 420-460 nm. In addition, in a subacid environment, Ca < 2 + > and H < + > in the octahedral ion cage spontaneously perform ion exchange, the pH of the microenvironment is increased, and Ca < 2 + > is released to assist in bone repair. The composite scaffold material formed by crosslinking the calcium-titanium octahedron and the collagen scaffold has good mechanical properties, and can simulate various bone types based on stress matching to recover the integrity of a bone macrostructure.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomaterials, and particularly relates to a calcium-titanium octahedron with photosensitive antibacterial properties, a preparation method thereof, and an application thereof. Background Art

[0002] The repair of infectious bone defects has always been a difficult point in clinical treatment. In a diseased state, bone defects (including fractures, pathological bone defects, and inflammatory bone defects) often occur in combination with open wounds and infectious foci. Given the multi-level complex structure of the bone-soft tissue structure, thorough debridement is often difficult to achieve, resulting in persistent bacterial infections.

[0003] As the initiating factor of the disease, the overgrowth of bacteria and the inflammatory response induced by endotoxin exacerbate the hypoxic state in the bone defect area, resulting in the accumulation of lactic acid, the destruction of the physiological weak alkaline environment, and the reduction of the viability of bone cells. Further, the dissolution of the bone microstructure in an acidic environment accelerates the loss of Ca 2+ ions, affecting the calcium uptake ability of osteoblasts. As the disease progresses, the destruction of the macroscopic bone morphology interrupts the continuity of the bone cortex, hinders stress transmission, and forms stress concentration points around the defect area, making it more likely to cause stress-induced bone loss or pathological fractures. During the slow recovery process of bone defects, due to the persistent inflammation, bone destruction and bone regeneration alternate, resulting in disordered bone structure. Eventually, it presents as a slow-healing, recurrent, and difficult-to-treat infectious bone defect. Currently, clinical treatment mainly induces bone regeneration through de-antigenized natural bone, but it does not have antibacterial, stress matching, and structure reconstruction functions.

[0004] The 420 - 460 nm wavelength band is a commonly used wavelength for medical blue light devices. If sterilization can be carried out in this wavelength band, a low-cost and highly efficient sterilization effect can be achieved under the existing medical conditions. Summary of the Invention

[0005] In view of the above problems, the present invention proposes a calcium-titanium octahedron with photosensitive antibacterial properties and applies it to the repair of bone defects. The present invention performs surface treatment on ultrapure calcium-titanium octahedron in absolute ethanol, increasing oxygen vacancies while wrapping organic groups on the surface, unexpectedly having photocatalytic antibacterial properties at a wavelength of 420 - 460 nm. The present invention inhibits the activity of pathogenic microorganisms, reduces the risk of external bacteria invasion, reconstructs the micro-macro structure in the bone, corrects the ion-structure disorder in the microenvironment, and promotes the regeneration of infectious bone defects.

[0006] One of the technical solutions of the present invention is to provide a preparation method of a calcium-titanium octahedron with photosensitive antibacterial properties, including the following steps: (1) Synthesis of ultrapure calcium-titanium octahedron; (2) Surface treatment of the calcium-titanium octahedron with absolute ethanol.

[0007] Specifically, the synthesis of the calcium-titanium octahedron described in step 1 is prepared by the following steps: (1) Prepare a solution of CaCl2 in ultrapure water at a concentration of 1-10 mol / L and dissolve it by ultrasonic treatment; (2) Add polyethylene glycol and stir well. The volume ratio of polyethylene glycol to ultrapure water is 6:1; (3) Add Ti(N-buoh) in an amount equimolar to CaCl2 and stir evenly; (4) Dropwise add 10M NaOH solution with the same volume as ultrapure water and stir for 30 minutes; (5) Calcinate at 180 °C in air for 15 hours to remove impurities, and grind to obtain ultrapure calcium-titanium octahedron.

[0008] The calcium ions are mediated by polyethylene glycol and can be cross-linked to free Ti nanoparticles in an alkaline environment. After removing organic impurities by calcination, an octahedral titanium-oxygen lattice structure containing calcium ions is obtained at 180 °C.

[0009] Preferably, the calcium-titanium ratio is 1:1.

[0010] Furthermore, the surface treatment described in step 2 includes the following steps: (1) Disperse the calcium-titanium octahedron in absolute ethanol; preferably, the concentration of the calcium-titanium octahedron in absolute ethanol is 20 mg / 3 ml; (2) Heat to 120 °C until the alcohol completely evaporates; (3) Repeat steps 1 and 2 until a yellowish-brown product is obtained.

[0011] When the calcium-titanium octahedron is heated in absolute ethanol, due to the reducibility of the hydroxyl group, the oxygen atoms in the calcium-titanium octahedron lattice are taken away by ethanol, forming a large number of oxygen vacancies. At the same time, ethanol is oxidized to acetaldehyde or acetic acid. Among them, the oxygen vacancies improve the electron flow of the calcium-titanium octahedron under photocatalysis and enhance its catalytic effect. At the same time, aldehyde groups, carboxyl groups, and carbonized particles are coated on the nanoparticles, further changing their surface properties and optical properties, making their appearance yellowish-brown, and promoting the red shift of the catalytic spectrum, so that a large amount of ROS can be generated under blue light, thus realizing photosensitized antibacterial.

[0012] The second technical solution of the present invention is to provide a calcium-titanium octahedron with photosensitized antibacterial properties prepared by the above method.

[0013] This octahedron has photocatalytic antibacterial properties at a wavelength of 420-460 nm while increasing oxygen vacancies and surface coating organic groups through surface treatment with absolute ethanol. And in a slightly acidic microenvironment (pH = 6.5), the calcium-titanium octahedron synthesized in the present invention can pass through Ca 2+ -H+ Spontaneous exchange, raising the pH of the solution while increasing the Ca concentration in the environment. 2+ Concentration.

[0014] The third technical solution of the present invention lies in providing an application of the above-mentioned calcium-titanium octahedron with photosensitive antibacterial properties in bone defect repair. When applying, it is necessary to prepare a composite material for bone defect repair with photosensitive antibacterial calcium-titanium octahedron.

[0015] Furthermore, the preparation of the composite material includes the following steps: (1) Mix the calcium-titanium octahedron with photosensitive antibacterial properties with a 10%-50% gelatin solution and stir at 60 °C for 2 hours; the pH value of the gelatin solution is 7; (2) Form by 3D printing; (3) Suspend and place in 5-20% glutaraldehyde vapor for 40 minutes under the support of a polytetrafluoroethylene film to solidify the mixed material; (4) Elute with 10%-50% glycine solution for 24 hours to obtain a latex-like finished product.

[0016] The mixing ratio of the calcium-titanium octahedron and the gelatin solution is matched according to the required bone stress. Taking a 12% gelatin solution as an example, a solid-liquid ratio of 9:1 can reach 2 MPa, and 1:1 can reach 0.5 MPa. Those skilled in the art can adjust according to needs to obtain a suitable ratio.

[0017] Furthermore, the 3D printing includes stereolithography printing, droplet spraying 3D printing, layer-by-layer pouring 3D printing, and extrusion 3D printing.

[0018] Furthermore, the preparation of the composite material includes the following steps: Prepare a 10%-50% GelMA solution, mix the calcium-titanium octahedron, and perform stereolithography printing at 505 nm. The curing time is set to 10 minutes. The mixing ratio of the calcium-titanium octahedron and the GelMA solution is matched according to the required bone stress. Taking a 50% GelMA solution as an example, a solid-liquid ratio of 9:1 can reach 2 MPa, and 1:1 can reach 0.5 MPa. Those skilled in the art can adjust according to needs to obtain a suitable ratio.

[0019] In the field of 3D printing, elastic materials such as collagen-based materials are difficult to be put into application because of their high material viscosity, which causes the extruded filaments to adhere to each other and makes it difficult to form. Calcium-titanium octahedron nanoparticles have good dispersibility and high strength. Integrating them into gelatin scaffolds can significantly improve the overall mechanical properties of the composite materials. At the same time, a large number of calcium-titanium nanoparticles reduce the viscosity of the composite materials while retaining their good fluidity, making the materials easier to extrude and form during the 3D printing process and reducing the problem of filament adhesion. By adding different proportions of calcium-titanium octahedron nanoparticles, bone structures with different densities can be simulated to achieve continuous stress transfer between cortical bone and cancellous bone.

[0020] The composite materials have excellent mechanical strength and resilience. They can not only recover as before under destructive stress, but also the elastic modulus of the materials increases as the applied stress increases. According to the different ratios of calcium-titanium octahedron and scaffold materials, an adjustable elastic modulus between 0.5 MPa and 2 MPa can be achieved, thus realizing personalized stress matching.

[0021] Calcium-titanium octahedron can be regarded as an ion cage, and the calcium ions at the center of its structure are not stable. In an acidic environment, every 2 hydrogen ions penetrate into the ion cage and exchange with 1 calcium ion, resulting in an increase in pH and calcium ions in the external solution. Calcium-titanium octahedron composite materials 2+ through photosensitive antibacterial effect, pH regulation effect, and Ca

[0022] The beneficial effects of the present invention are as follows: (1) The ultra-pure calcium-titanium octahedron is surface-treated in absolute ethanol, increasing oxygen vacancies and wrapping organic groups on the surface. Unexpectedly, it has photocatalytic antibacterial properties at a wavelength of 420 - 460 nm.

[0023] (2) In a slightly acidic microenvironment (pH = 6.5), the calcium-titanium octahedron synthesized in the present invention can increase the environmental pH and the Ca 2+ -H + concentration in the environment through spontaneous exchange. 2+ concentration in the environment through spontaneous exchange.

[0024] (3) The calcium-titanium octahedron composite material has an elastic modulus similar to that of cortical bone (2 MPa) or cancellous bone (0.5 MPa), thus repairing stress interruption.

[0025] (4) This composite material can be used for 3D printing. For example, it can be cross-linked with gelatin for extrusion printing or mixed with GelMA for photocuring printing.

[0026] (5) The calcium-titanium octahedron composite material effectively promotes the repair of infectious bone defects, and its new bone mass, bone contour, and bone density are all better than those of the control group. Description of the Drawings

[0027] Figure 1 are the powder, appearance and elasticity of Yellow-CaTiO3; Figure 2 are the SEM images of Yellow-CaTiO3; Figure 3 are the evaluation and comparison of the photosensitive antibacterial effects of Yellow-CaTiO3, CaTiO3 and TiO2; Figure 4 are the ion exchange conditions of Yellow-GaTiO3; Figure 5 are the verifications of the repair of infectious bone defects in Example 1. From left to right, they are infectious femoral defects, inflammatory bone defects around implants, and infectious tooth extraction sockets; Figure 6 are the comparison of the mechanical properties of Example 1 and gelatin; Figure 7 is a schematic diagram of a 3D printed scaffold. Detailed Embodiments

[0028] The following examples are used to further illustrate the present invention. Their purpose is to illustrate the present invention and should not be construed as limiting the scope of the present invention. Unless otherwise specified, all weight parts and weight percentages are used hereinafter.

[0029] The raw materials used in the present invention are all conventional commercially available products unless otherwise specified; the methods used in the present invention are all conventional methods in the art unless otherwise specified.

[0030] The following further illustrates the embodiments of the present invention through multiple examples.

[0031] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0032] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "the", and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0033] The Ti (N-buoh) described in the present invention is a dispersion system cross-linked by n-butanol and Ti, which is a commercially available product.

[0034] In the present invention, the ultra-pure calcium-titanium octahedron after surface treatment with absolute ethanol is represented by Yellow-CaTiO3.

[0035] Example 1 (1) Synthesis of calcium-titanium octahedron: 32 mmol of CaCl2 (3.25 g) was mixed into 10 mL of ultrapure water and completely dissolved under ultrasound. 60 mL of polyethylene glycol PEG was added and stirred well. Subsequently, 32 mmol of Ti (N-buoh) was added and stirred at high speed. Another 10 mL of 10 M NaOH solution was prepared and slowly added dropwise, and stirred for 30 minutes. Calcined at 180 °C for 15 hours, and continued to calcine in air to remove impurities, and then ground. Finally, about 2 g of calcium-titanium octahedron was obtained.

[0036] (2) Surface treatment of calcium-titanium octahedron: 200 mg of calcium-titanium octahedron was fully mixed in 30 mL of absolute ethanol, heated to 120 °C with a condenser + metal bath. After the alcohol completely evaporated, the above steps were repeated 20 times. After about 4 hours, a yellowish-brown finished product was obtained.

[0037] (3) Preparation of composite material: 12% gelatin was adjusted to neutral with 10 M NaOH solution, and calcium-titanium octahedron and gelatin solution were mixed at a mass ratio of 9:1, and stirred at 60 °C for 2 hours; after forming by extrusion 3D printing, it was suspended and placed in 10% glutaraldehyde vapor for 40 minutes to solidify the mixed material under the support of polytetrafluoroethylene film; eluted with 25% glycine solution for 24 hours, and the obtained finished product had a latex-like texture. It can be seen from Figure 2 and Figure 3 that compared with the natural perovskite with insufficient purity after surface treatment with absolute ethanol, the untreated ultra-pure calcium-titanium octahedron and titanium dioxide nanoparticles in the control group, the catalytic spectrum of the yellow calcium-titanium octahedron treated with absolute ethanol was significantly up-regulated at 420 - 460 nm. Compared with the natural perovskite with insufficient purity, the synthesized ultra-pure calcium-titanium octahedron, and titanium dioxide nanoparticles, the antibacterial test results of the yellow calcium-titanium octahedron with organic groups were ideal. The calcium-titanium octahedron has a pH regulation and calcium ion release effect in a weakly acidic (pH = 6.5) solution; as Figure 5As shown, when used for bone defect repair, it has good promoting effects in the reconstruction of infectious femoral defects, peri-implantitis defects, and infectious extraction socket defects in mice.

[0038] According to Figure 6 From the mechanical evaluation comparison between the gelatin material shown and the composite material prepared by the present invention, it can be seen that compared with the gelatin material, the calcium-titanium octahedron composite material still maintains the integrity of the material and good elastic modulus under destructive stress, and has good 3D printing performance.

[0039] Example 2 (1) Synthesis of calcium-titanium octahedron: 10 mmol of CaCl2 was mixed into 10 mL of ultrapure water and completely dissolved under ultrasound. 60 mL of polyethylene glycol PEG was added and stirred well. Subsequently, 10 mmol of Ti (N-buoh) was added and stirred at high speed. Another 10 mL of 10 M NaOH solution was prepared and slowly added dropwise, and stirred for 30 minutes. It was calcined at 180 °C for 15 hours, and then calcined in air to remove impurities and ground.

[0040] (2) Surface treatment of calcium-titanium octahedron: 200 mg of calcium-titanium octahedron was fully mixed with 30 mL of absolute ethanol, heated to 120 °C with a condenser + metal bath. After the alcohol was completely evaporated, the above steps were repeated 20 times. After about 4 hours, a yellowish-brown finished product was obtained.

[0041] (3) Preparation of composite material: 10% gelatin was adjusted to neutral with 10 M NaOH solution, and calcium-titanium octahedron and gelatin solution were mixed at a mass ratio of 1:1, and stirred at 60 °C for 2 hours; after forming by droplet spraying 3D printing, it was suspended and placed in 5% glutaraldehyde vapor for 40 minutes under the support of a polytetrafluoroethylene film to solidify the mixed material; it was eluted with 10% glycine solution for 24 hours, and the obtained finished product had a latex-like texture.

[0042] Example 3 (1) Synthesis of calcium-titanium octahedron: 100 mmol of CaCl2 was mixed into 10 mL of ultrapure water and completely dissolved under ultrasound. 60 mL of polyethylene glycol PEG was added and stirred well. Subsequently, 100 mmol of Ti (N-buoh) was added and stirred at high speed. Another 10 mL of 10 M NaOH solution was prepared and slowly added dropwise, and stirred for 30 minutes. It was calcined at 180 °C for 15 hours, and then calcined in air to remove impurities and ground.

[0043] (2) Surface treatment of calcium-titanium octahedron: 200 mg of calcium-titanium octahedron was fully mixed with 30 mL of absolute ethanol, heated to 120 °C with a condenser + metal bath. After the alcohol was completely evaporated, the above steps were repeated 20 times. After about 4 hours, a yellowish-brown finished product was obtained.

[0044] (3)Preparation of composite material: 50% gelatin was adjusted to neutral with 10M NaOH solution, and calcium-titanium octahedron and gelatin solution were mixed at a mass ratio of 5:1 and stirred at 60 °C for 2 hours; after forming by layer-by-layer casting 3D printing, it was suspended and placed in 20% glutaraldehyde vapor for 40 minutes to solidify the mixed material; eluted with 50% glycine solution for 24 hours, and the obtained product had a latex-like texture.

[0045] Example 4 The operation steps are the same as those in Example 2, except that GelMA solution is used to replace the gelatin solution, and the curing method is photocuring printing at 505 nm, and the curing time is set to 10 minutes.

[0046] Example 5 The operation steps are the same as those in Example 3, except that GelMA solution is used to replace the gelatin solution, and the curing method is photocuring printing at 505 nm, and the curing time is set to 10 minutes.

[0047] The above examples have detailed the structure, features and function effects of the present invention. The above are only the preferred embodiments of the present invention. Any changes made according to the concept of the present invention, or equivalent embodiments modified into equivalent changes, still within the scope covered by the specification, shall be within the protection scope of the present invention.

Claims

1. A preparation method of a calcium-titanium octahedron with photosensitive antibacterial properties, characterized in that, It includes the following steps: (1) Synthesis of ultra-pure calcium-titanium octahedron; (2) Surface treatment of calcium-titanium octahedron using absolute ethanol.

2. The preparation method according to claim 1, characterized in that, The synthesis of the ultra-pure calcium-titanium octahedron described in Step 1 is prepared through the following steps: (1) Prepare a solution of CaCl2 at 1 - 10 mol / L in ultra-pure water and dissolve it by ultrasonic treatment; (2) Add polyethylene glycol and stir well. The volume ratio of polyethylene glycol to ultra-pure water is 6:1; (3) Add Ti (N-buoh) with an equimolar amount to CaCl2 and stir evenly; (4) Dropwise add 10M NaOH solution with the same volume as ultra-pure water and stir for 30 minutes; (5) Calcinate at 180 °C in air for 15 hours to remove impurities and grind to obtain ultra-pure calcium-titanium octahedron.

3. The preparation method according to claim 1, wherein The surface treatment described in Step 2 includes the following steps: (1) Disperse the calcium-titanium octahedron in absolute ethanol; (2) Heat to 120 °C until the alcohol completely evaporates; (3) Repeat Step 1 and Step 2 until a yellowish-brown product is obtained.

4. A calcium-titanium octahedron with photosensitive antibacterial properties prepared by the preparation method according to any one of claims 1 - 3.

5. Use of the calcium-titanium octahedron as described in claim 4 in bone defect repair, characterized in that, Prepare a calcium-titanium octahedron bone defect repair composite material with photosensitive antibacterial properties.

6. The application according to claim 5, wherein It includes the following steps: (1) Mix the calcium-titanium octahedron with photosensitive antibacterial properties with a 10% - 50% gelatin solution and stir at 60 °C for 2 hours; the pH value of the gelatin solution is 7; (2) Form by 3D printing; (3) Suspend and place it in 5 - 20% glutaraldehyde vapor for 40 minutes under the support of a polytetrafluoroethylene film to solidify the composite material; (4) Elute with 10% - 50% glycine solution for 24 hours to obtain a latex-like finished product.

7. The application according to claim 6, wherein The 3D printing includes stereolithography printing, droplet spraying 3D printing, layer-by-layer pouring 3D printing, and extrusion 3D printing.

8. The application according to claim 5, wherein It includes the following steps: Prepare a 10% - 50% GelMA solution, mix it with the calcium-titanium octahedron with photosensitive antibacterial properties, and perform stereolithography printing at 505 nm. The curing time is set to 10 minutes.

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