Polymer composite hydrogel and preparation method therefor, and tooth desensitization material

Abstract

The present invention pertains to the technical field of materials. Disclosed are a polymer composite hydrogel and a preparation method therefor, and a tooth desensitization material. The polymer composite hydrogel consists of a GelMA hydrogel and BP nanosheets composited inside the GelMA hydrogel, wherein the GelMA hydrogel is prepared by crosslinking gelatin methacryloyl via double bonds under the action of a photoinitiator. Under the photothermal effect, the polymer composite hydrogel of the present invention can enhance the resistance of dentin to external stimuli and promote the formation of stable and effective occlusion of dentinal tubules. Moreover, the occlusion effect on the dentinal tubules exhibits acid resistance, corrosion resistance, and stability, preventing the possibility of short-term reopening of the occluded dentinal tubules. This is of great significance for the treatment of occluded dentin hypersensitivity (DH).

Description

A high-molecular composite hydrogel, a preparation method thereof and a tooth desensitizing material

[0001] The present application claims priority to the Chinese patent application No. 202410440030.8, filed on April 12, 2024, and entitled "A high-molecular composite hydrogel, a preparation method thereof and a tooth desensitizing material", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of materials, in particular to a high-molecular composite hydrogel, a preparation method thereof and a tooth desensitizing material. BACKGROUND

[0003] Hydroxyapatite (HA) is the main inorganic component of dentin. The change of the calcium-phosphorus ratio (Ca / P = 1.67) of HA will change the ratio of organic / inorganic components of dentin, ultimately changing the permeability of dentin. This change plays an important role in the mineralization, demineralization and remineralization of dentin. The gradual decrease of inorganic components of dentin causes the widespread opening of dentin tubules, thereby causing closed dentin hypersensitivity (DH). Currently, the nucleation and growth of HA can be induced by simulating the oral environment, introducing functional groups and providing mineralization conditions to promote the process of dentin mineralization and remineralization.

[0004] Black phosphorus (BP) has high photo-thermal conversion efficiency and is widely used in photo-thermal therapy in vitro and in vivo. At the same time, phosphorus is an essential element in the human body, and its degradation product in the body is mainly phosphate, which promotes the increase of local phosphate content. In addition, GelMA has been confirmed to have a calcium ion induction effect, which can recruit environmental calcium ions and phosphate to form mineralization in the body, and has an important role in promoting mineralization and remineralization.

[0005] At present, CN117018278A discloses a preparation method of a 3D-printed double-layer nanocomposite hydrogel scaffold for comprehensive repair of cartilage and bone, black phosphorus nanosheets (BP) are added to the GelMA / BExo hydrogel to adjust the concentration of phosphorus ions in the joint and promote cartilage repair. CN117338998A discloses a preparation method of a blue light synergistic carvacol microemulsion gel. The preparation method comprises the following steps: adding methacrylated gelatin (GelMA), lithium phenyl (2,4,6-trimethylbenzoyl) phosphate and hydroxypropyl methyl cellulose into water, mixing them thoroughly to prepare a gel suspension, then mixing the gel suspension with an oil-in-water carvacol microemulsion, and obtaining the carvacol microemulsion gel under blue light. The carvacol microemulsion gel has high stability, can reduce the volatilization of carvacol, can quickly form a gel in situ while synergistically acting on carvacol under 405 nm blue light, and has excellent effects such as antibiosis, hemostasis and healing promotion, and can be applied to the field of wound dressings. However, black phosphorus (BP) and / or GelMA are mainly applied to the fields of cartilage repair or wound dressings.

[0006] Therefore, it is of great significance to research and develop a DH-accompanied desensitizing material for exposing dentin tubules by utilizing the high photo-thermal conversion efficiency of black phosphorus and the calcium ion induction effect of GelMA, so as to promote the process of dentin mineralization and remineralization. SUMMARY

[0007] Therefore, the technical problem to be solved by the present application is to provide a high molecular composite hydrogel, a preparation method thereof and a tooth desensitizing material. The high molecular composite hydrogel has excellent dentin tubule sealing effect.

[0008] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0009] The present application provides a high molecular composite hydrogel, which is composed of a GelMA hydrogel and BP nanosheets compounded in the GelMA hydrogel.

[0010] The GelMA hydrogel is prepared by cross-linking of methacrylated gelatin under the action of a photoinitiator.

[0011] The particle size of the BP nanosheets is preferably 190.1±2.543 nm, and the zeta potential is preferably -21.6±1.763 mV.

[0012] The high molecular composite hydrogel has a high photo-thermal conversion rate, can stably convert light energy into heat energy, thereby melting the surface of dentin and realizing the reduction of the diameter of dentin tubules.

[0013] In addition, the high molecular composite hydrogel can increase the calcium-phosphorus ratio, promote the formation of hydroxyapatite (HAP) and improve the remineralization of dentin. 2+ and HPO4 2-Converted into HA, thus achieving bioremineralization.

[0014] Preferably, the photoinitiator is selected from one or more of phenyl (2,4,6-trimethylbenzoyl) phosphate lithium salt, 1,2-diketone, Irgacure 2959 (2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone; 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone); more preferably, phenyl (2,4,6-trimethylbenzoyl) phosphate lithium salt (ie, LAP).

[0015] The present invention also provides a method for preparing a polymer composite hydrogel, comprising the following steps:

[0016] 1) BP powder and N-methylpyrrolidone are mixed, and then liquid exfoliation is performed by ultrasound to obtain a BP monolayer flaky precipitate, which is then resuspended to obtain a BP suspension;

[0017] 2) mixing methacrylic anhydride-treated gelatin, a photoinitiator, and a buffer solution to obtain a GelMA solution;

[0018] 3) The BP suspension obtained in step 1) and the GelMA solution obtained in step 2) are mixed, and a double bond polymerization reaction is carried out by light initiation to obtain a polymer composite hydrogel.

[0019] Preferably, in the present invention, the ratio of BP powder to N-methylpyrrolidone in step 1) is (1-2) mg:1 mL; more preferably 2 mg:1 mL.

[0020] Preferably, in the step 2), the ratio of the photoinitiator to the buffer solution is (0.5-1) mg:10 mL; more preferably 1 mg:10 mL.

[0021] Preferably, the ratio of methacrylic anhydride gelatin to buffer in step 2) is (1-3) mg:10 mL; more preferably 3 mg:10 mL.

[0022] Preferably, the mixing temperature in step 2) is 37°C to 60°C; more preferably 60°C.

[0023] Preferably, the buffer in step 2) is selected from Dulbecco's phosphate buffered saline (DPBS) or phosphate buffered saline (PBS).

[0024] In some specific embodiments of the present invention, Dulbecco's phosphate buffered saline (DPBS) is preferred.

[0025] In the above preparation method, the BP suspension in step 3) can be prepared by resuspending the BP suspension prepared in step 1) by ultrasonic oscillation to remove the excess N-methylpyrrolidone solvent.

[0026] The resuspension by ultrasonic oscillation preferably uses deionized water.

[0027] In some embodiments of the present application, the suspension in step 3) is preferably diluted from the suspension in step 1).

[0028] The specific process is as follows:

[0029] After the above resuspension by ultrasonic oscillation, the water is preferably removed by lyophilization.

[0030] Then the lyophilized BP is reconstituted into a BP suspension.

[0031] In some embodiments of the present application, the concentration of the reconstituted suspension is preferably 200 μg / mL -1 or 100 μg / mL -1 or 50 μg / mL -1 .

[0032] Preferably in the present application, the volume ratio of the BP suspension in step 3) to the GelMA solution is (0.5-1):1; more preferably 1:1.

[0033] Preferably in the present application, when the BP suspension and the GelMA solution are mixed at a volume ratio of 1:1, the concentration of BP in the mixed solution in step 3) is preferably 25-100 μg / mL –1 ; more preferably 25 μg / mL –1 or 50 μg / mL –1 or 100 μg / mL –1 .

[0034] In the mixed solution, the concentration of the GelMA solution is preferably 10%-20% (W / V, the ratio of the mass of GelMA to the volume of the mixed solution); more preferably 10%-15%; further preferably 10% or 15%.

[0035] In the present application, the prepared polymer composite hydrogel containing different concentrations of BP is named GelMA / BP25 hydrogel or GelMA / BP50 hydrogel or GelMA / BP100 hydrogel.

[0036] The present application also provides a tooth desensitizing material comprising the above polymer composite hydrogel or the polymer composite hydrogel prepared by the above preparation method.

[0037] The tooth desensitizing material includes, but is not limited to, a pharmaceutical composition containing the above high-molecular composite hydrogel or a composite containing the above high-molecular composite hydrogel and the like.

[0038] The high-molecular composite hydrogel of the present application can make the Ca / P value of the dentin surface of the ex vivo tooth close to the normal value through photothermal therapy, and promote the formation of dentin surface mineral.

[0039] The dentin surface mineral is preferably hydroxyapatite (HA).

[0040] The high-molecular composite hydrogel of the present application can improve the resistance of dentin to external stimulation under the photothermal effect, and promote the effective sealing of dentin tubules.

[0041] In addition, the sealing of the dentin tubules has acid resistance, abrasion resistance and stability.

[0042] Therefore, the high-molecular composite hydrogel of the present application can be used to prepare a tooth desensitizing material, promote the sealing of dentin tubules, and treat dentin hypersensitivity (DH).

[0043] The prepared GelMA / BP50 hydrogel material is used for sealing the dentin tubules of human ex vivo and mouse DH models, respectively, and the excellent treatment effect of the high-molecular composite hydrogel of the present application on DH is proved.

[0044] Compared with the prior art, the high-molecular composite hydrogel provided by the present application is composed of a GelMA hydrogel and BP nanosheets compounded in the GelMA hydrogel, wherein the GelMA hydrogel is prepared by cross-linking methacrylanated gelatin through a double bond under the action of a photoinitiator. The high-molecular composite hydrogel of the present application can improve the resistance of dentin to external stimulation under the photothermal effect, promote the stable and effective sealing of dentin tubules, and the sealing of the dentin tubules has acid resistance, corrosion resistance and stability, avoiding the possibility of reopening of the sealed dentin tubules in a short period of time, which is of great significance for the treatment of DH. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 is a TEM diagram of the BP monolayer sheet-shaped precipitate prepared in step 1) of Example 1;

[0046] Figure 2 is a strain amplitude scanning (A) and strain-stress curve (B) diagram of the GelMA hydrogel;

[0047] Figure 3 is a Raman spectrum diagram of the high-molecular composite hydrogel;

[0048] Figure 4 is a schematic diagram of the construction of the high-molecular composite hydrogel;

[0049] Figure 5 shows the amplitude scanning strain diagram of the polymer composite hydrogel;

[0050] Figure 6 shows the strain-stress curve diagram of the polymer composite hydrogel;

[0051] Figure 7 is a comparison diagram of dentin tubule sealing effect of human in vitro tooth DH model, A is the DH model group, B is the single laser irradiation Laser group, and C is the GelMA / BP50 group;

[0052] Figure 8 is a comparison diagram of acid resistance, friction resistance and stability effect of human in vitro tooth DH after desensitization, wherein A is a schematic diagram of dentin slice challenge experiment of GelMA / BP50 group, B is FE-SEM characterization of dentin tubule sealing-GelMA / BP50 hydrogel group, acid resistance (C), friction resistance (D) and stability (E) of FE-SEM characterization of dentin tubule sealing, dentin tubule diameter (F) and sealing rate (G) after acid resistance, friction resistance and stability challenge experiment (P<0.05, NS: no statistical difference);

[0053] Figure 9 is a comparison diagram of dentin tubule sealing effect of rat DH model, A is the blank (Control) group, B is the single laser irradiation (Laser) group, and C is the GelMA / BP50 group. DETAILED DESCRIPTION

[0054] In order to further illustrate the present application, the polymer composite hydrogel and the preparation method thereof and the tooth desensitizing material provided by the present application are described in detail below in combination with examples.

[0055] Example 1

[0056] 1) Synthesis of BP single-layer sheet-shaped precipitate

[0057] The raw materials are BP powder and N-methyl-2-pyrrolidinone (NMP).

[0058] First, grind an appropriate amount of BP powder and add NMP to dilute the BP suspension to a concentration of 2 mg mL -1 Install the rough probe (probe diameter 6 mm) on the ultrasonic cell crusher, working power 30%, on / off working cycle time 3s / 3s, total liquid stripping time 20h. After the liquid stripping is completed, the BP suspension is centrifuged at 3500 rpm for 10 min, the precipitate is removed, the supernatant is centrifuged at 9000 rpm for 10 min, the supernatant is removed, and the BP single-layer sheet-shaped precipitate is resuspended to obtain the BP suspension (concentration 200 μg mL -1) standby, the structure of BP monolayer sheet precipitate is shown in Figure 1, Figure 1 is the TEM diagram of the prepared BP monolayer sheet precipitate.

[0059] 2) Configuration of GelMA solution

[0060] Dulbecco's Phosphate Buffered Saline (DPBS) (1X) was preheated in a 60°C water bath for 3 min;

[0061] An appropriate amount of lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) was weighed and dissolved in the preheated DPBS, wherein the LAP was 0.1% w / v (LAP mass / DPBS volume);

[0062] An appropriate amount of methacrylate gelatin (GelMA) sponge was weighed and dissolved in the solution containing LAP, wherein the GelMA was 30% w / v (GelMA mass / LAP DPBS solution volume), and the mixture was dissolved in a 60°C water bath for 20 min, with oscillation during dissolution to ensure complete dissolution. The whole process was carried out in the dark.

[0063] In addition, the above-mentioned 30% w / v GelMA solution was diluted to a concentration of 10% W / V and 15% W / V, and then 200 μL of solution was taken into a mold with a diameter of 1 cm and a height of 3 cm, and crosslinked by 405 nm blue light for 90 s to prepare GelMA hydrogel, which was used as the control group for the characteristic peaks of the Raman spectrum in Figure 3.

[0064] Figure 2 is a graph of amplitude scanning strain (A) and strain-stress curve (B) of GelMA hydrogel, which shows that the mechanical properties of 15% GelMA are better than those of 10% GelMA by comparing the mechanical properties of 10% and 15% GelMA through amplitude scanning strain and compression experiments. Therefore, 15% GelMA is preferred for subsequent experiments.

[0065] 3) Synthesis of polymer composite hydrogel

[0066] The BP suspension obtained in step 1) was resuspended in deionized water by ultrasonic oscillation, centrifuged at 9000 rpm for 10 min, the supernatant was discarded, and the BP precipitate was resuspended in deionized water by ultrasonic oscillation again, and the process was repeated three times to remove residual NMP.

[0067] Then the BP was freeze-dried and prepared into a suspension with a concentration of 200 μg mL -1 of the suspension was diluted by a factor of 100 μg mL-1 and 50 μg mL -1 .

[0068] Finally, the three BP suspensions of different concentrations were mixed with the 30% w / v GelMA solution in step 2) in a ratio of 1:1, and the two were thoroughly mixed under ultrasonic conditions (power: 80%, duration: 30 min). They were labeled as GelMA / BP25, GelMA / BP50, and GelMA / BP100, respectively. 200 μL of the solution was drawn into a mold with a diameter of 1 cm and a height of 3 cm, and the solution was exposed to 405 nm blue light for 90 seconds to prepare a polymer composite hydrogel. Figure 3 is a Raman spectrum of the polymer composite hydrogel. The results show that the final product contains characteristic peaks of GelMA and BP nanosheets. The present invention successfully prepared a polymer composite hydrogel.

[0069] Figure 4 is a schematic diagram of the construction of a polymer composite hydrogel. The results show that the polymer composite hydrogel prepared by the present invention is composed of GelMA hydrogel and BP nanosheets suspended inside the GelMA hydrogel, where the red line represents a double bond, the green dot represents a double bond bond, and the blue dot represents the location of black phosphorus.

[0070] Figure 5 shows the amplitude sweep strain diagram of the polymer composite hydrogel. The results show that, through the amplitude sweep strain comparison of the polymer composite hydrogel, GelMA / BP50 is preferred for desensitization experiments. Figure 6 shows the strain-stress curve of the polymer composite hydrogel. The results show that GelMA / BP50 has better mechanical properties. Therefore, GelMA / BP50 is used for subsequent human or animal dentinal tubule sealing treatment. The polymer composite hydrogel prepared in Example 1 is used for human or animal dentinal tubule sealing treatment.

[0071] (1) The specific process of human dentinal tubule sealing treatment is as follows:

[0072] 1) A healthy third molar was obtained from the patient and a 2 mm thick dentin slice was cut from the middle of the crown using a hard tissue cutter;

[0073] 2) The surface of the dentin slice was etched with 35% phosphoric acid to establish an in vitro tooth DH model;

[0074] 3) The surface of the dentin slice of the above-mentioned in vitro tooth DH model was coated with the polymer composite hydrogel prepared in Example 1, and then photothermal treatment was performed under 808nm laser conditions for 7 minutes. The treatment effect is shown in Figure 7. The DH model group was compared with the single laser irradiation Laser group. The results showed that the GelMA / BP50 hydrogel material of the present invention has a more excellent dentinal tubule sealing effect.

[0075] The human dentin slices treated by the GelMA / BP50 hydrogel above were divided into three parts by a hard tissue cutting machine.

[0076] In order to evaluate the acid resistance of the dentin slices after treatment, the dentin slices were soaked in 35% phosphoric acid for 30 seconds. The dentin slices were treated with an electric toothbrush for 30 seconds to test the friction resistance of the dentin slices. The stability of the dentin slices was verified by soaking in artificial saliva at 37℃ for 7 days.

[0077] The occlusion of dentin tubules was observed by FE-SEM and analyzed by ImageJ to evaluate the acid resistance, friction resistance and stability of the dentin slices.

[0078] The FE-SEM and ImageJ analysis of the surface of the dentin slices after the challenge experiment showed that there was no statistical difference in the diameter and occlusion rate of the dentin tubules. This indicates that the dentin slices treated by the GelMA / BP50 hydrogel have certain acid resistance, friction resistance and stability, which is of great significance to maintain the long-term effect of desensitization treatment (as shown in FIG. 8).

[0079] (II) The specific process of the animal dentin tubule occlusion treatment is as follows:

[0080] 1) SD male rats were selected, and the labial dentin of the incisors was exposed by a high-speed dental handpiece to establish a DH rat model;

[0081] 2) After modeling, the exposed part of the rat dentin of the DH rat model was coated with the polymer composite hydrogel material of the application for treatment, and the treatment effect is shown in FIG. 9. The results show that the GelMA / BP50 hydrogel material of the application has excellent dentin tubule occlusion effect compared with the Control group and the single laser irradiation Laser group.

[0082] In summary, the polymer composite hydrogel of the application can improve the resistance of dentin to external stimuli and promote the formation of stable and effective occlusion of dentin tubules.

[0083] The above examples are only used to help understand the method of the application and its core idea. It should be noted that for those skilled in the art, without departing from the principles of the application, some improvements and modifications can be made to the application, and these improvements and modifications also fall within the protection scope of the claims of the application.

Claims

1. A polymer composite hydrogel, characterized in that: It is composed of GelMA hydrogel and BP nanosheets composited inside the GelMA hydrogel; The GelMA hydrogel is prepared by double-bond crosslinking of methacrylic anhydride-treated gelatin under the action of a photoinitiator.

2. The polymer composite hydrogel according to claim 1, characterized in that The photoinitiator is selected from one or more of phenyl (2,4,6-trimethylbenzoyl) phosphate lithium salt, 1,2-diketone, and Irgacure 2959.

3. A method for preparing a polymer composite hydrogel, characterized in that: The following steps are involved: 1) BP powder and N-methylpyrrolidone are mixed, and then liquid exfoliation is performed by ultrasound to obtain a BP monolayer flaky precipitate, which is then resuspended to obtain a BP suspension; 2) mixing methacrylic anhydride-treated gelatin, a photoinitiator, and a buffer solution to obtain a GelMA solution; 3) The BP suspension obtained in step 1) and the GelMA solution obtained in step 2) are mixed, and a double bond polymerization reaction is carried out by light initiation to obtain a polymer composite hydrogel.

4. The preparation method according to claim 3, characterized in that The ratio of BP powder to N-methylpyrrolidone in step 1) is (1-2) mg:1 mL.

5. The preparation method according to claim 3, characterized in that The ratio of the photoinitiator to the buffer in the step 2) is (0.5-1) mg:10 mL.

6. The preparation method according to claim 3, characterized in that The ratio of methacrylic anhydride gelatin to buffer in step 2) is (1-3) mg:10 mL.

7. The preparation method according to claim 3, characterized in that The mixing temperature in step 2) is 37°C to 60°C.

8. The preparation method according to claim 3, characterized in that The buffer in step 2) is selected from Dulbecco's phosphate buffer or phosphate buffer solution.

9. The preparation method according to claim 3, characterized in that The volume ratio of the BP suspension to the GelMA solution in step 3) is (0.5-1):

1.

10. A tooth desensitizing material, characterized in that: The invention comprises the polymer composite hydrogel according to any one of claims 1 to 2 or the polymer composite hydrogel prepared by the preparation method according to any one of claims 3 to 9.

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