Silicon nitride ceramic composite material for interbody fusion cage and preparation method thereof

Abstract

The invention discloses a silicon nitride ceramic composite material for an interbody fusion device and a preparation method thereof, the composite material is composed of silicon nitride, liquid metal gallium and an osseointegration induction element, and the method comprises the following steps: preparation of basic components, sintering of the basic components, preparation of final components, and sintering of the final components. The ceramic composite material prepared by the preparation method disclosed by the invention has excellent biological activity, can promote inward growth of bone tissues, has good osteoconductivity and osteoinductivity, and also has good biomechanical properties. In addition, the preparation process provided by the invention is simple and convenient, is high in controllability and has a wide application prospect.

Description

Technical Field

[0001] The present invention belongs to the field of medical materials, and in particular relates to a silicon nitride-based ceramic composite material for an intervertebral fusion device and a preparation method thereof. Background Art

[0002] Due to multiple factors such as the high incidence of spinal degenerative diseases, advances in medical technology, and changes in people's lifestyles, the prevalence of diseases such as degenerative disc disease, spinal stenosis, and spondylolisthesis has increased significantly, especially in the elderly population. Intervertebral fusion is one of the standard surgeries for treating such diseases, used to stabilize the spinal structure, relieve nerve compression, and reduce pain. At the same time, with the continuous development of medical imaging technology, navigation equipment, and minimally invasive surgical instruments, the safety and accuracy of spinal fusion have been significantly improved, which has increased patient acceptance and expanded the scope of surgical indications, further promoting the clinical application of intervertebral fusion devices.

[0003] Currently, the mainstream materials used for interbody fusion cages include titanium alloys (such as Ti-6Al-4V), polyetheretherketone (PEEK), and bioceramics (such as hydroxyapatite HA or β-tricalcium phosphate β-TCP). Titanium alloys have excellent mechanical strength and biocompatibility, and can promote bone integration. However, their stiffness is much higher than that of human bone tissue, which can easily induce stress shielding, thereby affecting bone healing. PEEK, as a polymer material, has an elastic modulus close to that of cortical bone, which reduces stress shielding and does not produce metal artifacts in imaging, facilitating postoperative evaluation. However, it is a bioinert material and is difficult to induce bone integration. Surface modification is usually required to enhance its bone bonding ability. Bioceramic materials perform well in terms of biological activity, can promote the ingrowth of bone tissue, and have good osteoconductivity and osteoinductivity. However, they are brittle and have low mechanical strength, making them prone to fracture during load-bearing.

[0004] Based on the above problems, we introduced a silicon nitride@gallium-based liquid metal ceramic material for intervertebral fusion cage and its preparation method. Summary of the Invention

[0005] In view of this, in order to develop a new type of silicon nitride ceramic composite material for intervertebral fusion devices and a preparation method thereof, the inventors conducted a lot of in-depth research and completed the present invention after expending creative work.

[0006] More specifically, the present invention mainly relates to the following aspects.

[0007] In a first aspect, the present invention relates to a silicon nitride ceramic composite material for an intervertebral fusion cage, wherein the composite material is composed of silicon nitride, liquid metal Ga, and a bone integration inducing element.

[0008] Preferably, the bone integration inducing element is one or more of Ag, Mg and Ta.

[0009] The composite material is based on silicon nitride powder and uses liquid metal Ga as a sintering aid. The average particle size of the silicon nitride powder ranges from 0.1 μm to 5 μm. The particle size can be selected based on the model of the intervertebral fusion cage to optimize the mechanical properties of the ceramic material.

[0010] In a second aspect, the present invention also relates to a method for preparing a silicon nitride ceramic composite material for an intervertebral fusion cage, which specifically comprises the following steps: (1) Preparation of basic components: weigh a certain amount of silicon nitride powder, then add a certain amount of liquid metal Ga and grind and mix; (2) Sintering of basic components: The basic component mixture prepared in step (1) is preliminarily sintered in an electric furnace to obtain process material I; (3) Preparation of the final component: Add one or more of the bone integration inducing elements Ag, Mg, and Ta to process material I, grind and mix thoroughly to obtain the final component material; (4) Sintering the final component: The final component material prepared in step (3) is sintered in an electric furnace to finally obtain a silicon nitride ceramic composite material for an intervertebral fusion device.

[0011] Preferably, in step (1), the grinding time is 1 to 4 hours.

[0012] Preferably, in step (2), the sintering temperature of the basic component is 200-800° C., and the holding time is 8-12 hours.

[0013] Preferably, the grinding time in step (3) is 1 to 4 hours.

[0014] Preferably, in step (4), the temperature of the final component sintering is 800-1600° C., and the holding time is 6-12 hours.

[0015] Preferably, the amount of liquid metal gallium added in step (1) is: 1% to 5% by mass Preferably, in step (3), the amounts of the bone integration inducing elements Ag, Mg, and Ta added are: 0.5% to 2%, 1% to 5%, and 2% to 10% by mass, respectively.

[0016] The beneficial effects of the present invention are as follows: (1) Based on the ceramic sintering process, the present invention introduces gallium-based liquid metal and biologically beneficial elements such as silver (Ag), magnesium (Mg), and tantalum (Ta) that induce bone integration into silicon nitride ceramics, which significantly improves the biological activity, mechanical properties, and antibacterial properties of the material.

[0017] (2) Liquid metal gallium not only has good wettability and low melting point, but can also effectively promote the sintering between silicon nitride particles, thereby reducing the sintering temperature of ceramic materials.

[0018] (3) Added elements such as silver and magnesium have the dual effects of antibacterial and promoting osteogenesis. In particular, silver can effectively inhibit bacterial growth at low concentrations, which helps significantly reduce the risk of infection after intervertebral fusion surgery. In addition, tantalum, as a highly biocompatible metal element, can further enhance the material's ability to integrate into the human body.

[0019] (4) The method of the present invention adopts a multi-stage sintering and step-by-step addition strategy in terms of process, so that the functional components can be fully and evenly mixed and stably sintered at the appropriate stage, which not only ensures the structural stability of the material but also retains the biological activity of the functional elements.

[0020] (5) The composite material of the present invention not only has excellent biocompatibility and chemical inertness, meets the performance requirements of intervertebral fusion devices, and can reduce postoperative inflammatory reactions and foreign body rejection, but also has a naturally hydrophilic surface that facilitates cell attachment and bone integration, thereby accelerating the fusion process. It is the best new composite material for preparing intervertebral fusion devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to make the technical solutions involved in the embodiments of the present invention or the prior art more clear, the following will briefly introduce the drawings included in the embodiments or the prior art description. It should be noted that these drawings only record some specific embodiments of the present invention, not all embodiments.

[0022] Figure 1 It is a process flow chart of the present invention.

[0023] Figure 2 This is a SEM image of Example 1 at a magnification of ×3000.

[0024] Figure 3 This is a SEM image of Example 1 at a magnification of ×10,000.

[0025] Figure 4 This is a SEM image of Example 2 at a magnification of ×3000.

[0026] Figure 5 This is a SEM image of Example 2 at a magnification of ×10,000.

[0027] Figure 6 This is the EDS point scanning image of Example 1.

[0028] Figure 7 This is the load-displacement diagram of the nanoindentation test in Example 1. DETAILED DESCRIPTION

[0029] Next, all technical solutions involved in the present invention will be described clearly and completely. It should be understood that the embodiments described are only a part of the embodiments included in the present invention, not all embodiments. At the same time, based on the embodiments provided by the present invention, those skilled in the art can obtain all other embodiments without creative work, and these embodiments also fall within the scope protected by the present invention. In the following examples, the instruments and materials used are commercially available unless otherwise specified.

[0030] Example 1 Component design: Silicon nitride powder with a particle size of 0.5 μm, α-phase, and purity ≥92% is used as the basic component, liquid metal Ga is used as a sintering aid, and bone integration inducing elements are Ag, Mg, and Ta.

[0031] A method for preparing a silicon nitride ceramic composite material for an intervertebral fusion cage comprises the following steps: (1) Preparation of basic components: Weigh 1 g of silicon nitride powder, then add liquid metal Ga at a mass ratio of 40:1, and then grind thoroughly for 1 hour until the liquid metal Ga and silicon nitride powder are evenly mixed.

[0032] (2) Sintering of basic components: The basic component mixture prepared in step (1) was preliminarily sintered in an electric furnace at a sintering temperature of 600°C and a holding time of 12 h to obtain process material I.

[0033] (3) Preparation of the final component: Add trace amounts of the nutrients required by the organism, namely, the bone integration inducing elements Ag, Mg, and Ta, to process material I in a mass ratio of 0.5%, 1%, and 2%, respectively. Continue grinding for 1 hour to obtain the final component material.

[0034] Example 2 Component design: Silicon nitride powder with a particle size of 0.5 μm, α-phase, and purity ≥92% is used as the basic component, liquid metal Ga is used as a sintering aid, and bone integration inducing elements are Ag, Mg, and Ta.

[0035] A method for preparing a silicon nitride ceramic composite material for an intervertebral fusion cage comprises the following steps: (1) Preparation of basic components: Weigh 1 g of silicon nitride powder, then add liquid metal Ga at a mass ratio of 25:1, and then grind thoroughly for 4 hours until the liquid metal Ga and silicon nitride powder are evenly mixed.

[0036] (2) Sintering of basic components: The basic component mixture prepared in step (1) was preliminarily sintered in an electric furnace at a sintering temperature of 200°C and a holding time of 12 h to obtain process material I.

[0037] (3) Preparation of the final component: Add trace amounts of the nutrients required by the organism, namely, the bone integration inducing elements Ag, Mg, and Ta, to process material I, with the added mass ratios of 1%, 2%, and 5%, respectively. Continue grinding for 4 hours to obtain the final component material.

[0038] (4) Sintering of the final component: The final component material obtained in step (3) is sintered in an electric furnace at a sintering temperature of 1200°C and a holding time of 6 hours to finally obtain a silicon nitride ceramic composite material for intervertebral fusion cage. The SEM image of the composite material is shown in FIG. Figure 4 、 5 shown.

[0039] Example 3 Component design: Silicon nitride powder with a particle size of 0.5 μm, α-phase, and purity ≥92% is used as the basic component, liquid metal Ga is used as a sintering aid, and bone integration inducing elements are Ag, Mg, and Ta.

[0040] A method for preparing a silicon nitride ceramic composite material for an intervertebral fusion cage comprises the following steps: (1) Preparation of basic components: Weigh 1 g of silicon nitride powder, then add liquid metal Ga at a mass ratio of 25:1, and then grind thoroughly for 2 h until the liquid metal Ga and silicon nitride powder are evenly mixed.

[0041] (2) Sintering of basic components: The basic component mixture prepared in step (1) was preliminarily sintered in an electric furnace at a sintering temperature of 800°C for 8 hours to obtain process material I.

[0042] (3) Preparation of the final component: Add trace amounts of the nutrients required by the organism, namely, the bone integration inducing elements Ag, Mg, and Ta, to process material I, with the added mass ratios of 2%, 4%, and 10%, respectively. Continue grinding for 2 hours to obtain the final component material.

[0043] (4) Sintering of the final component: The final component material prepared in step (3) is sintered in an electric furnace at a sintering temperature of 1600°C and a holding time of 6 hours to finally obtain a silicon nitride ceramic composite material for an intervertebral fusion device.

[0044] Example 4 In this embodiment, the bone integration inducing element is Ag, and the added mass ratio is 1%. Other experimental parameters are the same as those in Example 1.

[0045] Example 5 In this embodiment, the bone integration inducing element is Mg, and the added mass ratio is 2%. Other experimental parameters are the same as those in Example 1.

[0046] Example 6 In this embodiment, the bone integration inducing element is Ta, and the added mass ratio is 5%. Other experimental parameters are the same as those in Example 1.

[0047] Example 7 In this embodiment, the bone integration inducing elements are Ag and Mg, and the added mass ratios are 2% and 1% respectively. Other experimental parameters are the same as those in Example 1.

[0048] Example 8 In this embodiment, the bone integration inducing elements are Ag and Ta, and the added mass ratios are 2% and 5% respectively. Other experimental parameters are the same as those in Example 1.

[0049] Example 9 In this embodiment, the bone integration inducing elements are Ta and Mg, and the added mass ratios are 5% and 2% respectively. Other experimental parameters are the same as those in Example 1.

[0050] The composite film obtained above was tested as follows: (1) Morphology analysis test Scanning electron microscopy test: The surface morphology of silicon nitride ceramic composites was tested using a scanning electron microscope to determine the density of the sample surface and whether there were defects. At the same time, an X-ray energy dispersion spectrum plug-in was used to perform quantitative and qualitative point scanning to observe the microstructure morphology and analyze the micro-region composition.

[0051] (2) Mechanical properties test Nanoindentation test: The elastic modulus and hardness of silicon nitride ceramic composite materials were tested using a nanoindentation tester to determine whether the mechanical requirements of the sample meet the mechanical properties required for intervertebral fusion devices.

[0052] The composite materials prepared in the above embodiments not only have excellent biocompatibility and chemical inertness, which can reduce postoperative inflammatory reactions and foreign body rejection, but also because their surfaces are naturally hydrophilic, they facilitate cell attachment and bone integration, thereby accelerating the fusion process. In addition, the properties of the silicon nitride ceramics obtained by sintering, such as the porosity and elastic modulus, can be controlled by sintering at different temperatures. Therefore, materials with different performance requirements can be produced by controlling the process.

Claims

1. A silicon nitride ceramic composite material for intervertebral fusion cage, characterized in that: The composite material consists of silicon nitride, liquid metal Ga and bone integration inducing elements.

2. The method for preparing the silicon nitride ceramic composite material for intervertebral fusion cage according to claim 1, characterized in that: The bone integration inducing element is one or more of Ag, Mg and Ta.

3. The method for preparing the silicon nitride ceramic composite material for intervertebral fusion cage according to claim 1, characterized in that: The composite material is based on silicon nitride powder and uses liquid metal Ga as a sintering aid; the average particle size of the silicon nitride powder is 0.1 μm to 5 μm; The particle size can be selected according to the model of the intervertebral fusion cage to optimize the mechanical properties of the ceramic material.

4. A method for preparing the silicon nitride ceramic composite material for intervertebral fusion cage according to any one of claims 1 to 2, characterized in that: The specific steps include: (1) Preparation of basic components: weigh a certain amount of silicon nitride powder, then add a certain amount of liquid metal Ga and grind and mix; (2) Sintering of basic components: The basic component mixture prepared in step (1) is preliminarily sintered in an electric furnace to obtain process material I; (3) Preparation of the final component: Add one or more of the bone integration inducing elements Ag, Mg, and Ta to process material I, grind and mix thoroughly to obtain the final component material; (4) Sintering the final component: The final component material prepared in step (3) is sintered in an electric furnace to finally obtain a silicon nitride ceramic composite material for an intervertebral fusion device.

5. The method for preparing the silicon nitride ceramic composite material for intervertebral fusion cage according to claim 4, characterized in that: In step (1), the grinding time is 1 to 4 hours.

6. The method for preparing the silicon nitride ceramic composite material for intervertebral fusion cage according to claim 4, characterized in that: In step (2), the sintering temperature of the basic component is 200-800°C.

7. The method for preparing the silicon nitride ceramic composite material for intervertebral fusion cage according to claim 4, characterized in that: The grinding time of step (3) is 1 to 4 hours.

8. The method for preparing the silicon nitride ceramic composite material for intervertebral fusion cage according to claim 4, characterized in that: In step (4), the temperature of the final component sintering is 800~1600℃.

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