Low-temperature preparation method of biomimetic mineralized dental material

Abstract

The invention discloses a low-temperature preparation method of a biomimetic mineralized dental material, which comprises the following steps of: (1) adding a microorganism sporosarcina pasteurii capable of generating calcium carbonate into a microorganism fermentation liquid capable of generating protein fibers for co-culture to obtain a fibrous biofilm containing the sporosarcina pasteurii; (2) adding the biological membrane into a mineralizing solution for biological mineralization; and (3) after mineralization is finished, performing high-temperature sterilization and drying on the material to obtain the biomimetic mineralized dental material. By adopting an in-situ mineralization technology and combining microbial co-culture with a biomineralization assembly technology, the preparation of the super-hard and super-tough bionic ceramic dental material can be realized under the near room temperature condition of 30 DEG C, and the super-high energy consumption of a traditional high-temperature sintering technology is avoided; the Vickers hardness HV value of the dental material prepared by the method is about 300 and is close to that of natural enamel, and the tensile toughness value of the dental material is 18 MJ / m < 3 > and is 10 times of that of natural teeth.

Description

Technical Field

[0001] This invention relates to the field of dental material preparation technology, specifically to a low-temperature preparation method for biomimetic mineralized dental materials. Background Technology

[0002] Human teeth and bones possess a high degree of hardness and toughness due to their naturally mineralized, multi-level structure. Current dental materials primarily use traditional metals, ceramics, or resins for fillings or implants. Among these materials, metals often lack biocompatibility and can easily trigger allergic reactions; resin materials lack sufficient mechanical strength and are prone to aging; ceramic materials, due to their mechanical properties and composition closely resembling those of natural teeth, are the ideal choice for dental materials.

[0003] Traditional ceramic materials are mostly prepared using high-temperature sintering technology, resulting in high hardness, good temperature resistance, good corrosion resistance, and a certain degree of bioinertness; however, ceramics are also brittle, making it difficult to simultaneously achieve both hardness and toughness; in addition, the material manufacturing requires high temperatures, and the manufacturing process is complex and energy-intensive. Summary of the Invention

[0004] The technical problem to be solved by this invention is to overcome the technical defects of the prior art and provide a low-temperature preparation method for biomimetic mineralized dental materials. This invention employs in-situ mineralization technology, combining microbial co-culture with biomineralization assembly technology, to achieve the preparation of ultra-hard and ultra-tough biomimetic ceramic dental materials at near-room temperature (30℃), avoiding the extremely high energy consumption of traditional high-temperature sintering techniques. The dental materials prepared using this method have a Vickers hardness (HV) of approximately 300, close to that of natural tooth enamel, and a tensile toughness of 18 MJ / m. 3 It is 10 times tougher than natural teeth.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0006] A low-temperature preparation method for a biomimetic mineralized dental material includes the following steps:

[0007] (1) Using microbial direct fermentation technology, the microorganism Bacillus pasteurellii that produces calcium carbonate is directly added to the microbial fermentation broth that produces protein fiber for co-culture, thereby obtaining a fiber biofilm containing Bacillus pasteurellii.

[0008] (2) The biofilm is added to the mineralization solution for biomineralization. When the mineralization solution enters the biofilm, it will adhere to the protein fibers under the action of Pasteurella multocida and grow inorganic calcium carbonate particles.

[0009] (3) After mineralization, the material is sterilized at high temperature to remove microorganisms; and then dried in an oven to finally obtain biomimetic mineralized dental material.

[0010] Preferably, in step (1), the calcium carbonate-producing microorganism *Bacillus pasteurellus* is directly added to the protein fiber-producing microbial fermentation broth for co-culture at 15-35 °C. More preferably, the calcium carbonate-producing microorganism *Bacillus pasteurellus* is directly added to the protein fiber-producing microbial fermentation broth for co-culture at room temperature (25-30 °C).

[0011] Preferably, in step (1), the OD of the *Pasteurella multocida* is... 600 =0.1~0.8, more preferably 0.5.

[0012] Preferably, in step (1), the microorganism that produces protein fibers is Escherichia coli, seaweed, or fungus, and its OD... 600 =0.1~0.8, more preferably 0.5.

[0013] Preferably, in step (1), the composition of the microbial fermentation broth that produces protein fibers is: 5~15 g / L peptone, 1~10 g / L yeast extract, 5~15 g / L sodium chloride, more preferably: 10 g / L peptone, 5 g / L yeast extract, 10 g / L sodium chloride.

[0014] Preferably, in step (2), the mineralization solution comprises: calcium chloride: 0.1~1.5 M, urea: 0.1~1.5 M, culture medium: 1~15 mL / L, more preferably: calcium chloride: 1 M, urea: 1 M, culture medium: 10 mL / L; the culture medium comprises: 5~15 g / L peptone, 1~10 g / L yeast extract, 5~15 g / L ammonium chloride, more preferably: 10 g / L peptone, 5 g / L yeast extract, 10 g / L ammonium chloride.

[0015] Preferably, in step (2), the mineralization time is 6 to 48 hours, more preferably 12 hours.

[0016] Preferably, in step (3), the high-temperature sterilization temperature is 121 °C and the time is 3 h.

[0017] Preferably, in step (3), the drying temperature is 30~70 ℃, more preferably 60 ℃, and the time is 12 hours.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] (1) This invention adopts an original microbial co-culture technology to realize a two-step preparation strategy of first growing biological fiber membrane and then nesting inorganic crystals, so as to realize the room temperature preparation of ultra-hard and ultra-tough ceramic materials; the special mechanical interlocking structure of fibers and inorganic crystals brought about by the in-situ fermentation technology of this invention provides a guarantee for the improvement of the mechanical properties of materials.

[0020] (2) Existing technologies mostly use the method of physically mixing the dispersion with calcium carbonate. Because the calcium carbonate and the fiber are only physically mixed, there is a lack of strong bonding force, which makes the microstructure and macroscopic mechanical properties of the material unstable. In this invention, the calcium carbonate particles grow in situ in the natural structure of the layered protein fiber and are tightly intercalated with the protein fiber. Therefore, during the drying process of the material, the fiber and inorganic material will be densified and shrink, thus forming a bio-fiber reinforced composite material with high strength and high toughness.

[0021] (3) The present invention adopts in-situ mineralization technology and combines microbial co-culture with biomineralization assembly technology to prepare ultra-hard and ultra-tough biomimetic ceramic dental materials at near room temperature of 30°C, avoiding the ultra-high energy consumption of traditional high-temperature sintering technology.

[0022] (4) The dental material prepared by the method of the present invention has a Vickers hardness (HV) of around 300, which is close to that of natural tooth enamel, and a tensile toughness of 18 MJ / m. 3 It is 10 times tougher than natural teeth. Attached Figure Description

[0023] Figure 1 This is a process flow diagram of the low-temperature preparation method of the biomimetic mineralized dental material of the present invention (the meanings of each symbol in the diagram are as follows: Microorganism 1: Escherichia coli (producing protein fibers); Microorganism 2: Bacillus pasteurellii (mineralizing and growing calcium carbonate); Orange part: protein fiber biofilm; Red line: protein fiber; Blue part: mineralization solution; Gray cube: calcium carbonate inorganic crystal; Brown cylinder: fiber mineralized dental material).

[0024] Figure 2 This is a microstructure diagram of the biomimetic mineralized dental material prepared in Example 1 of the present invention;

[0025] Figure 3 This is a diagram showing the mechanical interlocking structure of nanofibers and inorganic calcium carbonate in the biomimetic mineralized dental material prepared in Example 1 of this invention. Detailed Implementation

[0026] To better understand the content of this invention, further description is provided below with reference to specific embodiments and accompanying drawings. It should be understood that these embodiments are only for further illustration of the invention and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the description of this invention, those skilled in the art may make some non-essential modifications or adjustments to the invention, which still fall within the protection scope of this invention.

[0027] Example 1

[0028] A low-temperature preparation method for biomimetic mineralized dental materials, the process flow of which is as follows: Figure 1 As shown, the specific steps are as follows:

[0029] (1) Using direct microbial fermentation technology, calcium carbonate-producing microorganisms (Pasteurella multocida, OD) are fermented at room temperature. 600 =0.5) is directly added to the microorganisms that produce protein fibers (E. coli, OD) 600 =0.5) fermentation broth (composition: 10 g / L peptone, 5 g / L yeast extract, 10 g / L sodium chloride) was co-cultured to obtain a fibrous biofilm containing Bacillus pasteurellii;

[0030] (2) The biofilm was added to a mineralization solution (calcium chloride: 1 M, urea: 1 M, culture medium: 10 mL / L (10 g / L peptone, 5 g / L yeast extract, 10 g / L ammonium chloride)) for 12 hours for biomineralization. When the mineralization solution entered the biofilm, it would adhere to the protein fibers under the action of Bacillus pasteurellus and grow inorganic calcium carbonate particles.

[0031] (3) After mineralization, the material was sterilized at high temperature (121 ℃, 3 h) to remove microorganisms; and then dried in an oven at 60 ℃ for 12 hours to finally obtain the biomimetic mineralized dental material. Its microstructure is shown in […]. Figure 2 The mechanical interlocking structure between the nanofibers and inorganic calcium carbonate is shown in [the figure]. Figure 3 .

[0032] The biomimetic mineralized dental material prepared in this embodiment was tested and found to have a Vickers hardness of HV=300 and a tensile toughness of 18MJ / m. 3 .

[0033] The Vickers hardness test method involves using a diamond pyramid as an indenter, pressing it into the surface of the material under test with a certain test load (200 gf), holding it for 10 seconds, and then removing the load. The hardness value of the material is calculated by measuring the diagonal length of the indentation, using the following formula:

[0034] HV=1.8544×F / d 2 ;

[0035] Where: HV represents the Vickers hardness value; F represents the test load (in Newtons); d represents the diagonal length of the indentation (in millimeters).

[0036] The tensile toughness test method is as follows: The sample (50 mm * 10 mm) is fixed in the Instron universal testing machine (range 1 kN) with a clamping distance of 30 mm. The tensile test is performed at a speed of 2 mm / min. The tensile toughness value is obtained by integrating the stress-strain curve.

[0037] The foregoing description is not intended to limit the invention, nor is the invention limited to the examples given. Any changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the invention should also be considered within the protection scope of the invention.

Claims

1. A low-temperature preparation method for a biomimetic mineralized dental material, characterized in that, Includes the following steps: (1) Add the calcium carbonate-producing microorganism Bacillus pasteurellii to the fermentation broth of the protein fiber-producing microorganism for co-culture to obtain a fiber biofilm containing Bacillus pasteurellii. (2) The biofilm was added to a mineralization solution for biomineralization; (3) After mineralization, the material is sterilized at high temperature and dried to obtain biomimetic mineralized dental material.

2. The low-temperature preparation method of a biomimetic mineralized dental material as described in claim 1, characterized in that, In step (1), the calcium carbonate-producing microorganism Bacillus pasteurellus is added to the protein fiber-producing microbial fermentation broth for co-culture at 15~35 ℃.

3. The low-temperature preparation method of a biomimetic mineralized dental material as described in claim 1, characterized in that, In step (1), the OD of the *Pasteurella multocida* 600 =0.1~0.

8.

4. The low-temperature preparation method of a biomimetic mineralized dental material as described in claim 1, characterized in that, In step (1), the microorganism that produces protein fibers is any one of Escherichia coli, seaweed, or fungi.

5. The low-temperature preparation method of a biomimetic mineralized dental material as described in claim 1, characterized in that, OD of the microorganisms that produce protein fibers 600 =0.1~0.

8.

6. The low-temperature preparation method of a biomimetic mineralized dental material as described in claim 1, characterized in that, In step (1), the composition of the microbial fermentation broth that produces protein fibers is: 5~15 g / L peptone, 1~10 g / L yeast extract, and 5~15 g / L sodium chloride.

7. The low-temperature preparation method of a biomimetic mineralized dental material as described in claim 1, characterized in that, In step (2), the mineralization solution consists of: calcium chloride: 0.1~1.5 M, urea: 0.1~1.5 M, and culture medium: 1~15 mL / L.

8. The low-temperature preparation method of a biomimetic mineralized dental material as described in claim 7, characterized in that, The culture medium consists of 5-15 g / L peptone, 1-10 g / L yeast extract, and 5-15 g / L ammonium chloride.

9. The low-temperature preparation method of a biomimetic mineralized dental material as described in claim 1, characterized in that, In step (2), the mineralization time is 6 to 48 hours.

10. The low-temperature preparation method of a biomimetic mineralized dental material as described in claim 1, characterized in that, In step (3), the high-temperature sterilization temperature is 121 °C and the time is 3 h.

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