Polydopamine coating driven bionic oriented layered ceramic and preparation method thereof

Abstract

The invention discloses a polydopamine coating driven bionic oriented layered ceramic and a preparation method thereof, and relates to the field of bionic materials. The method comprises the following steps: under an ultrasonic condition, dispersing nano ceramic particles and dopamine hydrochloride in a Tris hydrochloric acid buffer solution, stirring at room temperature for 10-12 hours, and sequentially centrifuging, washing, drying and grinding to obtain polydopamine modified 3Y-TZP powder; uniformly mixing the polydopamine modified 3Y-TZP powder with a polymer solution, and carrying out ball milling for 1-3 hours to obtain slurry; and uniformly ball-milling the obtained slurry, pouring into a mold, cooling to-90 to-70 DEG C at the speed of 2.5 DEG C / min, keeping for 1-3 hours under the temperature condition, freeze-drying for 5-7 days in a vacuum freeze-drying machine, and finally roasting. The technology is safer, simpler and more convenient, the global orientation structure of the material is stable, and the material is suitable for mass production.

Description

Technical Field

[0001] The invention relates to the field of bionic materials, and in particular to a polydopamine coating-driven bionic directional layered ceramic and a preparation method thereof. Background Art

[0002] Currently, the main dental implant materials are pure titanium, titanium alloys, ceramics, polymers, etc. Among them, although titanium has excellent compatibility with human tissues, can promote bone integration and reduce rejection reactions, metal debris and electrochemical corrosion can easily aggravate peri-implantitis, and the metal color is dark and unsightly, which is not very friendly to patients with thin gingival biotypes; ceramic materials can provide a more natural appearance, and their bone integration and cuff closure properties are both excellent, but compared with titanium, ceramics are brittle, and surface modification is prone to produce microcracks. They may break when subjected to large bite forces, and they are difficult to process, which increases the production cost; polymer materials have good elasticity and can buffer chewing forces to a certain extent and reduce trauma to surrounding bone tissues, but they have poor wear resistance and may wear out after long-term use, affecting the stability and service life of the implant.

[0003] The patent with publication number CN 109966549 A, titled "A three-dimensional bionic bone repair material and its preparation method", uses a bidirectional freezing method to prepare a long-range global directional structure, while the fiber intersection points are effectively bonded and interconnected through dopamine cross-linking. Due to the need to use special freezing casting technology, the freezing casting instrument and the subsequent vacuum freeze-drying process are relatively high, and the order parameters are not close to those of cortical bone.

[0004] Commercially available 3 mol% yttria-stabilized tetragonal polycrystalline zirconia ceramics (3Y-TZP) as dental implants remain a clinical challenge, partly due to the inadequate surface and structural design for effective bone integration. Conventional micro / nano-machining may introduce microcracks that weaken the strength of zirconia, and its highly ordered surface is not conducive to osteogenesis. Summary of the invention

[0005] In view of the above problems, the present invention provides a polydopamine coating driven bionic directional layered ceramic and a preparation method and application thereof.

[0006] The purpose of the present invention can be achieved by the following measures:

[0007] A method for preparing polydopamine coating-driven biomimetic oriented layered ceramics, the method comprising the following steps:

[0008] (1) under ultrasonic conditions, the nano-ceramic particles and dopamine hydrochloride are dispersed in a Tris hydrochloric acid buffer and stirred at room temperature for 10 to 12 hours, followed by centrifugation, washing, drying and grinding to obtain polydopamine-modified 3Y-TZP powder;

[0009] (2) mixing the polydopamine-modified 3Y-TZP powder with the polymer solution and ball milling for 1 to 3 hours to obtain a slurry;

[0010] (3) The obtained slurry is ball-milled and poured into a mold, and then cooled to -90 to -70°C at a rate of 2.5°C / min, maintained at this temperature for 1 to 3 hours, and then freeze-dried in a vacuum freeze dryer for 5 to 7 days, and finally calcined.

[0011] In the above preparation method, the concentration of Tris hydrochloric acid buffer in step (1) is 5-15 mM, and the pH value is 8-9.

[0012] In the above preparation method, in step (1), the mass ratio of nano-ceramic particles to dopamine hydrochloride is 15-25:5-10.

[0013] In the above preparation method, the polymer solution in step (1) is prepared by mixing hydroxyethyl cellulose, Dynol 604 and polyvinyl alcohol with water, wherein the concentration of hydroxyethyl cellulose in the polymer solution is 0.1-1wt%, the concentration of Dynol 604 is 0.5-1.5wt%, and the concentration of polyvinyl alcohol is 1-5%.

[0014] In the above preparation method, the content of polydopamine modified 3Y-TZP powder in the slurry in step (2) is 40-60wt%.

[0015] In the above preparation method, the freeze-drying temperature in step (3) is -50 to -30°C.

[0016] In the above preparation method, the calcination conditions in step (3) are pre-calcination at 480-520°C for 1-3 hours, followed by calcination at 1500-1600°C for 2-4 hours.

[0017] A polydopamine coating driven bionic oriented layered ceramic is prepared by the method.

[0018] In the technical solution of the present invention, the polydopamine coating prepared by the method drives the application of biomimetic oriented layered ceramics as dental implant materials.

[0019] The polydopamine coating driven bionic directional layered ceramics of the present invention are specifically nano-3Y-TZP (nano-3Y-TZP) formed by sintering 3 mol% yttria-stabilized tetragonal polycrystalline zirconia ceramic (3Y-TZP) particles with a polydopamine coating after global directional arrangement.

[0020] In the technical solution of the present invention, the dopamine coating is only used to drive the long-range directional structure. The dopamine coating is decomposed at high temperature during the sintering process in the later stage. The final material is pure ceramic without other organic components. Therefore, the technology is simpler and easier to convert to mass production, and reduces ethical disputes. At the same time, we use the polydopamine coating of nano-ceramic particles in combination with the freeze casting technology to manipulate ice crystal nucleation and growth, and obtain a biomimetic directional layered structure with order parameters similar to cortical bone. In addition, the fully ordered structure is conducive to large-scale production. Therefore, this technology only realizes the global directional arrangement of nano 3Y-TZP particles through the polydopamine coating, the technology is simpler and easier to mass produce, and the prepared material is closer to the order parameters of cortical bone, and the mechanical biological properties have been experimentally verified to be better.

[0021] In the technical solution of the present invention, a polydopamine coating is prepared on the surface of inorganic nano-ceramic particles, and then a gradient freeze-casting process and a sintering process are used to drive and obtain bionic directional layered ceramics, which are close to the order parameters of cortical bones. This technical solution requests invention patent protection.

[0022] In the technical solution of the present invention, the bionic oriented layered ceramic has a global long-range oriented structure, which is close to the order parameter of cortical bone, is conducive to the polarization and osteogenic differentiation of mesenchymal stem cells, and can be used in bone tissue engineering and implants.

[0023] Beneficial effects of the present invention:

[0024] Considering the aesthetics and metal-free requirements of clinical implants, the use of zirconia implants is an alternative. However, improper surface design and preparation can easily lead to microcracks in zirconia and reduce mechanical properties. This technology is safer, simpler and more convenient, and the global directional structure of the material is stable and suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the manufacturing process of the present invention, as well as a macroscopic image of the material before and after sintering and a scanning electron microscope image of the cross section.

[0026] Figure 2 Directed permutation order parameter. DETAILED DESCRIPTION

[0027] The following examples are provided for better understanding of the present invention, but are not intended to limit the present invention. The experimental methods in the following examples are conventional methods unless otherwise specified. The experimental materials used in the following examples are purchased from conventional biochemical reagent stores unless otherwise specified.

[0028] Examples 1 to 3

[0029] (1) Under ultrasonic conditions, 20 g of nano-ceramic particles and 8 g of dopamine hydrochloride were ultrasonically dispersed in Tris hydrochloric acid buffer (10 mM, pH 8.5) and stirred at room temperature for 12 hours, followed by centrifugation, washing, drying and grinding to obtain polydopamine-modified 3Y-TZP powder;

[0030] (2) The polydopamine-modified 3Y-TZP powder was mixed with the polymer solution and ball-milled for 1 to 3 hours to obtain a slurry; wherein the concentration of hydroxyethyl cellulose in the polymer solution was 0.5wt%, the concentration of Dynol 604 was 0.75wt%, and the concentration of polyvinyl alcohol was 2wt%. The content of the polydopamine-modified 3Y-TZP powder in the slurry was 40wt% (Example 1), 53wt% (Example 2), and 60wt% (Example 3).

[0031] (3) The slurry is poured into Teflon molds of the desired shape. These molds are placed on the copper cold fingers of a homemade directional freezer. The lower surface of the cold finger is immersed in a liquid nitrogen storage tank. A thermal detector and a ring heater are installed on the top of the cold finger to record the temperature of the copper base of the mold, and the cooling rate is preset accordingly at 2.5°C / min, cooled to -80°C, and maintained at temperature conditions for 3 hours, during which layered ice crystals grow vertically and parallel. Finally, they are replaced by layered pores after freeze drying in a vacuum freeze dryer at -40°C for 1 week. Finally, the unsintered block is transferred to a sintering furnace, pre-fired at 500°C for 2 hours to remove organic matter, and then sintered at 1550°C for 3 hours to form a stable tetragonal zirconia phase.

[0032] Comparative Example 1

[0033] Other conditions were the same as in Example 1, except that 3Y-TZP powder was not modified with polydopamine and only 3Y-TZP powder was used.

[0034] Compared with conventional laser surface treatment technology and other proportions of inorganic substances prepared by this technology, the order parameter of this technology is closest to the order parameter of cortical bone when the inorganic component is 53wt%, and the biological effect is the best.

[0035] Figure 1 The macroscopic images and cross-sectional SEM images of the materials formed in Examples 1 to 3 are shown in FIG. Figure 1 shown.

[0036] Figure 2 It is the directional arrangement order parameter of Examples 1 to 3, Comparative Example 1 and conventional laser surface treatment technology.

Claims

1. A method for preparing a polydopamine coating-driven biomimetic oriented layered ceramic, characterized in that: The method comprises the following steps: (1) under ultrasonic conditions, the nano-ceramic particles and dopamine hydrochloride are dispersed in a Tris hydrochloric acid buffer and stirred at room temperature for 10 to 12 hours, followed by centrifugation, washing, drying and grinding to obtain polydopamine-modified 3Y-TZP powder; (2) mixing the polydopamine-modified 3Y-TZP powder with the polymer solution and ball milling for 1 to 3 hours to obtain a slurry; (3) The obtained slurry is ball-milled and poured into a mold, and then cooled to -90 to -70°C at a rate of 2.5°C / min, maintained at this temperature for 1 to 3 hours, and then freeze-dried in a vacuum freeze dryer for 5 to 7 days, and finally calcined.

2. The preparation method according to claim 1, characterized in that: The concentration of the Tris hydrochloric acid buffer in step (1) is 5-15 mM, and the pH value is 8-9.

3. The preparation method according to claim 1, characterized in that: In step (1), the mass ratio of nano-ceramic particles to dopamine hydrochloride is 15-25:5-10.

4. The preparation method according to claim 1, characterized in that: In step (2), the polymer solution is prepared by mixing hydroxyethyl cellulose, Dynol 604 and polyvinyl alcohol with water. The concentration of hydroxyethyl cellulose in the polymer solution is 0.1-1 wt %, the concentration of Dynol 604 is 0.5-1.5 wt %, and the concentration of polyvinyl alcohol is 1-5%.

5. The preparation method according to claim 1, characterized in that: The content of polydopamine modified 3Y-TZP powder in the slurry in step (2) is 40-60wt%.

6. The preparation method according to claim 1, characterized in that: The freeze-drying temperature in step (3) is -50 to -30°C.

7. The preparation method according to claim 1, characterized in that: The calcination conditions in step (3) are pre-calcination at 480-520° C. for 1-3 hours, followed by calcination at 1500-1600° C. for 2-4 hours.

8. A polydopamine coating driven bionic oriented layered ceramic, which is prepared by the method according to any one of claims 1 to 7.

9. Application of the polydopamine coating-driven biomimetic oriented layered ceramics prepared by the method of claim 1 as dental implant material.

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