Continuous oxygen supply / acid response root canal disinfection hydrogel as well as preparation method and application thereof

Abstract

The invention provides a continuous oxygen supply / acid response root canal disinfection hydrogel as well as a preparation method and application thereof, and belongs to the technical field of biomedical materials. The hydrogel is prepared from aldehyde group modified hyaluronic acid, methacrylated gelatin, antibiotics and catalase loaded ZIF-8, a network structure is formed through a Schiff base reaction, and the continuous oxygen supply and acid response characteristics are achieved. The preparation method comprises the following steps: hydroformylation of hyaluronic acid, loading of catalase on ZIF-8, and blending and chemical crosslinking of the components in a specific pH buffer solution, the obtained hydrogel is suitable for disinfection of root canal microenvironment, has excellent continuous oxygen supply and acid response performance, and provides a new efficient disinfection material for root canal treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical materials, and in particular relates to a continuous oxygen supply / acid response root canal disinfection hydrogel and a preparation method and application thereof. Background Art

[0002] Pulp and periapical disease is one of the most common infectious diseases that threaten human health. Bacterial infection is a key factor in the development and progression of inflammation in the dental pulp and periapical tissues. Normal oral microbiota maintain a permanent home in the host, maintaining a balance between microorganisms and the host. However, if these bacteria enter normally sterile areas (such as the root canal system) and resist the host's immune system, they become opportunistic pathogens, disrupting the balance between bacteria and the host and leading to root canal infection. Most root canal infections occur when the dental crown is damaged by caries, fractures, or wear, exposing the pulp cavity to oral microorganisms. This leads to inflammation and necrosis of the dental pulp, ultimately resulting in a loss of resistance to microorganisms. The second most common cause is periapical disease, which allows microorganisms to retrogradely enter the dental pulp through the apical foramen or lateral and accessory root canals, causing chronic inflammation in the periapical tissues. Compared to infections in other tissues, root canal infections present unique characteristics. Clearance through the body's immune system and systemic antimicrobial therapy is impossible. This is because the root canals are surrounded by impermeable dentin and lack effective blood circulation.

[0003] To date, root canal treatment is the preferred method for treating pulp disease and periapical periodontitis. Modern root canal treatment is divided into three steps: root canal preparation, root canal disinfection, and root canal filling. Perfect root canal disinfection is one of the necessary factors to ensure the success of root canal treatment. Common root canal disinfection methods currently include physical disinfection methods, such as laser disinfection, ultrasonic disinfection, and light-activated disinfection lamps, as well as chemical disinfection methods, such as root canal irrigation and root canal sealing. Antibiotics can be used as the active ingredient of root canal sealing for root canal disinfection. The main cause of pulp disease or periapical periodontitis is bacterial infection, and anaerobic bacteria are the dominant bacteria in root canal infection. Under inflammatory conditions, the pressure in the blood vessels of the pulp cavity increases, making oxygen supply more difficult, resulting in an oxygen-deficient environment for the periapical tissues, further aggravating periapical inflammation. In the existing technology, studies have used light-cured hydrogels to carry drugs for root canal disinfection. However, light-cured hydrogels are difficult to cure in narrow root canals, affecting the disinfection efficiency. At the same time, the existing hydrogel system is only used for drug delivery and has a single function. It cannot improve the anaerobic environment, limit the aggregation of inflammatory cells and the rapid reproduction of anaerobic bacteria, and the disinfection efficiency needs to be improved. Summary of the Invention

[0004] To overcome the shortcomings of the above-mentioned prior art, the present invention aims to provide a continuous oxygen supply / acid-responsive root canal disinfection hydrogel, as well as its preparation method and application. By preparing a chemically cross-linked hydrogel system, carrying antibiotics and catalase (Cat), the hypoxic microenvironment of the root canal is improved while enhancing the bactericidal ability of the antibiotics.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A first objective of the present invention is to provide a continuous oxygen supply / acid-responsive root canal disinfection hydrogel, comprising aldehyde-modified hyaluronic acid, methacrylated gelatin (GelMA), antibiotics, and catalase-loaded ZIF-8 (ZIF-8@Cat). The aldehyde-modified hyaluronic acid and GelMA react with a Schiff base to form a hydrogel network, and the catalase-loaded ZIF-8 and the antibiotics are dispersed in the hydrogel network.

[0006] Preferably, the antibiotic used in the hydrogel is triple antibiotic paste (TAP), which is equal in mass of metronidazole, minocycline, and ciprofloxacin.

[0007] A second object of the present invention is to provide a method for preparing the above-mentioned continuous oxygen supply / acid response root canal disinfection hydrogel, comprising the following steps: Aldehyde modification of hyaluronic acid: Aldehyde modification of hyaluronic acid to obtain aldehyde-modified hyaluronic acid; Catalase loaded into ZIF-8: Catalase was blended with hollow ZIF-8 to produce ZIF-8@Cat. Blending: GelMA, antibiotics, the aldehyde-modified hyaluronic acid, and the ZIF-8@Cat are blended in a buffer solution for chemical cross-linking, wherein the pH of the buffer solution is 7.4-10.5, to prepare the continuous oxygen supply / acid-responsive root canal disinfection hydrogel.

[0008] Preferably, in the above blending step: Dissolve GelMA in a buffer solution, and add the ZIF-8@Cat thereto to form a prepolymer solution A; dissolving aldehyde-modified hyaluronic acid in a buffer solution, and adding antibiotics thereto to form a prepolymer solution B; Mix prepolymer solution A and prepolymer solution B evenly. The buffer solution can be sodium carbonate-sodium bicarbonate buffer. Further preferably, in the prepolymer solution A, the concentration of GelMA is 10 wt% to 14 wt%, and the concentration of ZIF-8@Cat is not higher than 0.5 wt% and not 0; In the prepolymer solution B, the concentration of the aldehyde-modified hyaluronic acid is 6 wt % to 10 wt %, and the concentration of the antibiotic is not higher than 0.05 wt % and is not 0; The prepolymer liquid A and the prepolymer liquid B are mixed in equal amounts.

[0009] Preferably, in the step of aldehyde formation of hyaluronic acid: hyaluronic acid is dissolved in water to form a hyaluronic acid solution, sodium periodate is added to the hyaluronic acid solution and stirred, and then ethylene glycol is added and stirred, and after terminating the reaction, dialyzed, frozen, and dried to obtain the aldehyde-formylated hyaluronic acid.

[0010] Further preferably, the concentration of the hyaluronic acid solution is 1.5 wt% to 2.5 wt%; the amount of sodium periodate added is 0.5 times the amount of hyaluronic acid added; and the amount of ethylene glycol added is equal to the amount of hyaluronic acid added.

[0011] More preferably, sodium periodate is added to the hyaluronic acid solution under light-shielding conditions and stirred for at least 20 hours; ethylene glycol is added and stirred for at least 1 hour; and after terminating the reaction, the solution is dialyzed in water for at least 60 hours.

[0012] Preferably, in the loading of catalase in ZIF-8: catalase: zinc nitrate hexahydrate: water are mixed and dissolved in a mass ratio of (0.03-0.05): (0.13-0.17): 5 to prepare solution X, 2-methylimidazole: anhydrous methanol are mixed and dissolved in a mass ratio of (0.30-0.35): 10 to prepare solution Y, solution X and solution Y are mixed and stirred to prepare a suspension, the suspension is centrifuged, and the solid product is collected and washed and dried to prepare the ZIF-8@Cat.

[0013] Preferably, the mass ratio of solution X to solution Y is (5.16-5.22): (10.30-10.35).

[0014] A third objective of the present invention is to disclose the application of the above-mentioned continuous oxygen supply / acid-responsive root canal disinfection hydrogel. The hydrogel can act as a disinfectant in the root canal microenvironment, consume free radicals in the root canal microenvironment through ZIF-8@Cat, and undergo a chemical Schiff base reaction in the acidic inflammatory root canal environment, thereby providing continuous oxygen supply and acid response.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a continuous oxygen supply / acid-responsive root canal disinfection hydrogel. The hydrogel is composed of aldehyde-modified hyaluronic acid, GelMA, antibiotics and ZIF-8@Cat. A hydrogel network structure is formed through a Schiff base reaction. ZIF-8@Cat eliminates excessive oxygen free radicals in the root canal and supplies oxygen to the hypoxic microenvironment of the root canal, thereby inhibiting the reproduction of anaerobic bacteria in the root canal. At the same time, the hydrogel network is used to carry antibiotics for synergistic effect with ZIF-8@Cat, further improving the antibacterial ability of the antibiotics.

[0016] The present invention uses buffer solutions of different pH values ​​to promote the formation of a stable Schiff base reaction between aldehyde-modified hyaluronic acid and GelMA, and uniformly disperses ZIF-8@Cat and antibiotics in a hydrogel solution to improve the antibacterial properties of the composite material. The present invention promotes the formation of Schiff base bonds by regulating pH conditions, and uniformly disperses ZIF-8@Cat and antibiotics to achieve the unification of continuous oxygen supply and antibacterial properties, solves the problems of chemical crosslinking of aldehyde-modified hyaluronic acid and GelMA and root canal hypoxia, and obtains a continuous oxygen supply / acid response hydrogel root canal disinfection composite material with excellent antibacterial properties. Furthermore, in this application, a triple antibiotic paste can also be used as an antibiotic component to avoid the drug resistance problem easily produced by using a single antibiotic or a dual antibiotic. In this application, ZIF-8@Cat continuously supplies oxygen, increases the antibacterial ability of the triple antibiotic, quantifies the dosage of the antibiotic, and avoids the abuse of antibiotics.

[0017] The continuous oxygen supply / acid-responsive root canal disinfection hydrogel proposed in the present invention is used for root canal disinfection, which can achieve the unification of continuous oxygen supply and antibacterial performance, and solve the problems of chemical cross-linking of aldehyded hyaluronic acid and GelMA and root canal hypoxia. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a characterization diagram of the hydrogel of the present invention; Figure 2 Graph showing the injectability and self-healing properties of the hydrogel of the present invention; Figure 3 The continuous release of oxygen diagram of the present invention; Figure 4 The bacterial colony plate count and crystal violet staining diagram of the hydrogel group of the present invention; Figure 5 The SEM images and live and dead bacteria staining images of the antibacterial properties of each group of hydrogels of the present invention are as follows; Figure 6 Schematic diagram of the hydrogel function of the present invention. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0020] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0021] The present invention is described in further detail below with reference to the accompanying drawings: Example 1 Add 2 parts hyaluronic acid (by weight) to 100 parts deionized water and stir until completely dissolved. Add 1 part sodium periodate and stir for 24 hours in the dark. Then, add 2 ml of ethylene glycol and stir for 1 hour to terminate the reaction. Dialyze in deionized water for 3 days and freeze-dry to obtain aldehyde-modified hyaluronic acid (OHA).

[0022] Dissolve 0.04 parts of Cat and 0.15 parts of zinc nitrate hexahydrate in 5 parts of ultrapure water; dissolve 0.33 parts of 2-methylimidazole in 10 parts of anhydrous methanol. After sonicating both solutions for 10 minutes, the zinc nitrate solution was rapidly added to the 2-methylimidazole solution under magnetic stirring. After stirring for 15 minutes, the solution became a milky white suspension, thus synthesizing ZIF-8@Cat. The product was then collected by centrifugation at 10,000 rpm for 15 minutes and washed three times with methanol. The white product was dried in a vacuum oven at 50°C for 24 hours.

[0023] 12 parts of GelMA were added to 100 parts of a solution (sodium carbonate-sodium bicarbonate buffer with a pH of 7.4) to obtain solution A, and 0.5 parts of ZIF-8@Cat were evenly dispersed in solution A to obtain solution B.

[0024] 8 parts of aldehyde-modified hyaluronic acid were added to 100 parts of a solution (sodium carbonate-sodium bicarbonate buffer solution at pH = 7.4) to obtain solution C. 0.05 parts of TAP (metronidazole:minocycline:ciprofloxacin = 1:1:1) were evenly dispersed in solution C to obtain solution D.

[0025] One part of solution B and one part of solution D were mixed evenly to prepare a continuous oxygen supply / acid-responsive hydrogel root canal disinfection composite material with excellent antibacterial properties.

[0026] Example 2 Add 2 parts hyaluronic acid by weight to 100 parts deionized water and stir until completely dissolved. Add 1 part sodium periodate and stir for 24 hours in the dark. Then, add 2 ml of ethylene glycol and stir for 1 hour to terminate the reaction. Dialyze in deionized water for 3 days and freeze-dry to obtain the aldehyde-modified hyaluronic acid.

[0027] Dissolve 0.04 parts of Cat and 0.15 parts of zinc nitrate hexahydrate in 5 parts of ultrapure water; dissolve 0.33 parts of 2-methylimidazole in 10 parts of anhydrous methanol. After sonicating both solutions for 10 minutes, the zinc nitrate solution was rapidly added to the 2-methylimidazole solution under magnetic stirring. After stirring for 15 minutes, the solution became a milky white suspension, thus synthesizing ZIF-8@Cat. The product was then collected by centrifugation at 10,000 rpm for 15 minutes and washed three times with methanol. The white product was dried in a vacuum oven at 50°C for 24 hours.

[0028] 12 parts of GelMA were added to 100 parts of a solution (sodium carbonate-sodium bicarbonate buffer with a pH of 9.2) to obtain solution A, and 0.5 parts of ZIF-8@Cat were evenly dispersed in solution A to obtain solution B.

[0029] 8 parts of aldehyde-modified hyaluronic acid were added to 100 parts of a solution (sodium carbonate-sodium bicarbonate buffer solution at pH = 9.2) to obtain solution C. 0.05 parts of TAP (metronidazole:minocycline:ciprofloxacin = 1:1:1) were evenly dispersed in solution C to obtain solution D.

[0030] One part of solution B and one part of solution D were mixed evenly to prepare a continuous oxygen supply / acid-responsive hydrogel root canal disinfection composite material with excellent antibacterial properties.

[0031] Example 3 Add 2 parts hyaluronic acid by weight to 100 parts deionized water and stir until completely dissolved. Add 1 part sodium periodate and stir for 24 hours in the dark. Then, add 2 ml of ethylene glycol and stir for 1 hour to terminate the reaction. Dialyze in deionized water for 3 days and freeze-dry to obtain the aldehyde-modified hyaluronic acid.

[0032] Dissolve 0.04 parts of Cat and 0.15 parts of zinc nitrate hexahydrate in 5 parts of ultrapure water; dissolve 0.33 parts of 2-methylimidazole in 10 parts of anhydrous methanol. After sonicating both solutions for 10 minutes, the zinc nitrate solution was rapidly added to the 2-methylimidazole solution under magnetic stirring. After stirring for 15 minutes, the solution became a milky white suspension, thus synthesizing ZIF-8@Cat. The product was then collected by centrifugation at 10,000 rpm for 15 minutes and washed three times with methanol. The white product was dried in a vacuum oven at 50°C for 24 hours.

[0033] 12 parts of GelMA were added to 100 parts of a solution (sodium carbonate-sodium bicarbonate buffer with a pH of 10.5) to obtain solution A, and 0.5 parts of ZIF-8@Cat were evenly dispersed in solution A to obtain solution B.

[0034] 8 parts of aldehyde-modified hyaluronic acid were added to 100 parts of a solution (sodium carbonate-sodium bicarbonate buffer solution at pH = 10.5) to obtain solution C. 0.05 parts of TAP (metronidazole:minocycline:ciprofloxacin = 1:1:1) were evenly dispersed in solution C to obtain solution D.

[0035] One part of solution B and one part of solution D were mixed evenly to prepare a continuous oxygen supply / acid-responsive hydrogel root canal disinfection composite material with excellent antibacterial properties.

[0036] Example 4 Add 2 parts hyaluronic acid by weight to 100 parts deionized water and stir until completely dissolved. Add 1 part sodium periodate and stir for 24 hours in the dark. Then, add 2 ml of ethylene glycol and stir for 1 hour to terminate the reaction. Dialyze in deionized water for 3 days and freeze-dry to obtain the aldehyde-modified hyaluronic acid.

[0037] Dissolve 0.04 parts of Cat and 0.15 parts of zinc nitrate hexahydrate in 5 parts of ultrapure water; dissolve 0.33 parts of 2-methylimidazole in 10 parts of anhydrous methanol. After sonicating both solutions for 10 minutes, the zinc nitrate solution was rapidly added to the 2-methylimidazole solution under magnetic stirring. After stirring for 15 minutes, the solution became a milky white suspension, thus synthesizing ZIF-8@Cat. The product was then collected by centrifugation at 10,000 rpm for 15 minutes and washed three times with methanol. The white product was dried in a vacuum oven at 50°C for 24 hours.

[0038] 12 parts of GelMA were added to 100 parts of a solution (sodium carbonate-sodium bicarbonate buffer with a pH of 10.5) to obtain solution A, and 0.5 parts of ZIF-8@Cat were evenly dispersed in solution A to obtain solution B.

[0039] 6 parts of aldehyde-modified hyaluronic acid were added to 100 parts of a solution (sodium carbonate-sodium bicarbonate buffer solution at pH = 10.5) to obtain solution C. 0.05 parts of TAP (metronidazole:minocycline:ciprofloxacin = 1:1:1) were evenly dispersed in solution C to obtain solution D.

[0040] One part of solution B and one part of solution D were mixed evenly to prepare a continuous oxygen supply / acid-responsive hydrogel root canal disinfection composite material with excellent antibacterial properties.

[0041] Example 5 Add 2 parts hyaluronic acid by weight to 100 parts deionized water and stir until completely dissolved. Add 1 part sodium periodate and stir for 24 hours in the dark. Then, add 2 ml of ethylene glycol and stir for 1 hour to terminate the reaction. Dialyze in deionized water for 3 days and freeze-dry to obtain the aldehyde-modified hyaluronic acid.

[0042] Dissolve 0.04 parts of Cat and 0.15 parts of zinc nitrate hexahydrate in 5 parts of ultrapure water; dissolve 0.33 parts of 2-methylimidazole in 10 parts of anhydrous methanol. After sonicating both solutions for 10 minutes, the zinc nitrate solution was rapidly added to the 2-methylimidazole solution under magnetic stirring. After stirring for 15 minutes, the solution became a milky white suspension, thus synthesizing ZIF-8@CAT. The product was then collected by centrifugation at 10,000 rpm for 15 minutes and washed three times with methanol. The white product was dried in a vacuum oven at 50°C for 24 hours.

[0043] 12 parts of GelMA were added to 100 parts of a solution (sodium carbonate-sodium bicarbonate buffer with a pH of 10.5) to obtain solution A, and 0.5 parts of ZIF-8@Cat were evenly dispersed in solution A to obtain solution B.

[0044] 10 parts of aldehyde-modified hyaluronic acid were added to 100 parts of a solution (sodium carbonate-sodium bicarbonate buffer solution at pH = 10.5) to obtain solution C. 0.05 parts of TAP (metronidazole:minocycline:ciprofloxacin = 1:1:1) were evenly dispersed in solution C to obtain solution D.

[0045] One part of solution B and one part of solution D were mixed evenly to prepare a continuous oxygen supply / acid-responsive hydrogel root canal disinfection composite material with excellent antibacterial properties.

[0046] Test Case The continuous oxygen supply / acid-responsive hydrogel root canal disinfection composite material prepared in the above embodiment was subjected to chemical cross-linking data testing.

[0047] Please see the attached Figure 1 , Figure 1 In the figure a, the infrared spectrum of the hydrogel prepared in Example 3 is shown. It can be seen that the infrared image of the aldehyded hyaluronic acid has a wave number of 1735 cm −1The characteristic peak at 1735 cm indicates the aldehyde group structure in the spectrum. At the same time, the aldehyde group was also found in GelMA-OHA hydrogel. −1 The characteristic peak at 1640 cm −1 The characteristic peaks of the α-H-type ...

[0048] Figure 1 Figure b shows the sustained release rate of ZIF-8@Cat at different pH = 5.5 and pH = 7.4. It can be seen that the release rate at pH = 5.5 is higher than that at pH = 7.4. Figure 1 In the figure (c), the swelling properties of the hydrogels prepared in Examples 3, 4, and 5 are shown. The hydrogels in each group reached swelling equilibrium in about 8 h, and the swelling ratios were all higher than 60%.

[0049] Figure 1 Figure d in the middle is the XRD pattern of ZIF-8 and ZIF-8@Cat. By comparing the patterns, it can be seen that the structure of ZIF-8@Cat has not changed compared with the structure of ZIF-8, and the structure of ZIF-8@Cat is stable.

[0050] Please see the attached Figure 2 , Figure 2 (a) and (b) are the tests of hydrogel gelation performance. It can be seen that the fluidity of the hydrogel changes significantly after standing for a period of time, from a fluid to a colloid. Figure 2 Middle (c) is the test of the hydrogel's injectability. It can be seen that the hydrogel can be continuously injected, showing good injectability. Figure 2 (d) and (e) show the self-healing properties of the hydrogel. It can be seen that the hydrogel is dyed and evenly divided into two parts. After 1 hour, the hydrogel re-forms into a whole.

[0051] Please see the attached Figure 3 Figure a is the standard curve formed by different concentrations of H2O2 and absorbance. It can be seen that different concentrations of H2O2 have a good linear relationship with absorbance; Figure b is the reaction diagram of different concentrations of ZIF-8@Cat and quantitative H2O2. The concentration of ZIF-8@Cat increases from left to right. After 1 hour, it can be seen that the higher the concentration of ZIF-8@Cat in the ep tube, the more bubbles there are, which proves that more oxygen is produced.

[0052] Please see the attached Figure 4Figures a and b show the colony plate counts after co-culturing TAP with bacteria at different concentrations and the corresponding quantitative analysis based on the colony plate counts. It can be seen that with the increase of TAP concentration, the number of colonies on the plate decreases. When the TAP concentration reaches 0.04~0.05mg / mL, the antibacterial rate reaches 100%; Figures c and d show the colony plate counts after co-culturing bacteria with quantitative concentrations of TAP + different concentrations of ZIF-8@Cat and the corresponding quantitative analysis based on the colony plate counts. It can be seen that when the ZIF-8@Cat concentration reaches 0.1~0.5mg / mL, the antibacterial rate reaches 100%.

[0053] Figure 4 The hydrogels prepared in Example 3 were used for efficacy testing, including crystal violet staining of the control group, hydrogel alone group, hydrogel + ZIF-8 group, hydrogel + ZIF-8@Cat group, hydrogel + TAP group, and hydrogel + ZIF-8@Cat + TAP group. Each hydrogel group was co-cultured with an Enterococcus faecalis biofilm. The hydrogel + TAP + Cat group had the smallest biofilm area, demonstrating the best antibacterial performance compared to the other groups.

[0054] See also Figure 5 , the effect test was carried out using the hydrogel prepared in Example 3: Figure 5 Figures a to f in the middle are scanning electron micrographs of the control group, simple hydrogel group, hydrogel + ZIF-8 group, hydrogel + ZIF-8@Cat group, hydrogel + TAP group, and hydrogel + ZIF-8@Cat + TAP group, respectively. Figure 5 Figures g to l in the middle are the bacterial live and dead staining images of the control group, simple hydrogel group, hydrogel + ZIF-8 group, hydrogel + ZIF-8@Cat group, hydrogel + TAP group, and hydrogel + ZIF-8@Cat + TAP group, respectively. Each group was co-cultured with Enterococcus faecalis biofilm and characterized by scanning electron microscopy. The hydrogel + TAP + Cat group, i.e. Figure 5 The Enterococcus faecalis in Figure f is the least, while the other groups have more and denser Enterococcus faecalis, proving that the hydrogel+TAP+Cat group has the best antibacterial performance compared with other groups.

[0055] Attachment Figure 5 As shown in Figures g to l in the middle, each group of hydrogels was co-cultured with Enterococcus faecalis biofilms, and the bacteria were stained for live and dead bacteria and observed under a confocal microscope. Among them, the hydrogel + TAP + Cat group (Figure 1) had the largest number of dead bacteria, while the other groups had fewer dead bacteria, proving that the hydrogel + TAP + Cat group had the best antibacterial performance compared with the other groups.

[0056] like Figure 6As shown, the hydrogel designed in this invention first synthesizes a double-tube injectable hydrogel, one tube containing GelMA-encapsulated ZIF-8 loaded with Cat, and the other tube containing aldehyde-modified hyaluronic acid encapsulating TAP, thereby synthesizing a double-tube injectable acid-responsive hydrogel. The smart hydrogel is then injected into the root canal of a tooth with apical periodontitis to exert its bactericidal effect. The hydrogel releases Cat in the acidic microenvironment, catalyzing the conversion of excess reactive oxygen species (ROS) into O2, thereby enhancing the bactericidal ability of TAP.

[0057] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A continuous oxygen supply / acid response root canal disinfection hydrogel, characterized in that: The invention comprises hyaluronic acid modified with aldehyde groups, methacryloyl gelatin, antibiotics and ZIF-8 loaded with catalase; the hyaluronic acid modified with methacryloyl gelatin react with Schiff base to form a hydrogel network, and the ZIF-8 loaded with catalase and the antibiotics are dispersed in the hydrogel network.

2. The continuous oxygen supply / acid responsive root canal disinfection hydrogel according to claim 1, characterized in that: The antibiotic is TAP.

3. The method for preparing the continuous oxygen supply / acid response root canal disinfection hydrogel according to claim 1 or 2, characterized in that: The following steps are involved: Aldehydeation of hyaluronic acid: Aldehyde groups are modified on hyaluronic acid to obtain aldehyded hyaluronic acid; Loading catalase in ZIF-8: Catalase is mixed with ZIF-8 having a hollow structure to prepare ZIF-8 loaded with catalase; Blending: The aldehyde-modified hyaluronic acid, the catalase-loaded ZIF-8, methacrylylated gelatin and antibiotics are blended in a buffer solution for chemical cross-linking, wherein the pH value of the buffer solution is 7.4-10.5, thereby obtaining the continuous oxygen supply / acid-responsive root canal disinfection hydrogel.

4. The method for preparing the continuous oxygen supply / acid response root canal disinfection hydrogel according to claim 3, characterized in that: In the blend: Dissolving the methacrylylated gelatin in a buffer solution, and adding the catalase-loaded ZIF-8 thereto to form a prepolymer solution A; Dissolving the aldehyde-modified hyaluronic acid in a buffer solution, and adding the antibiotic thereto to form a prepolymer solution B; Mix prepolymer liquid A and prepolymer liquid B evenly.

5. The method for preparing the continuous oxygen supply / acid response root canal disinfection hydrogel according to claim 4, characterized in that: In the prepolymer solution A, the concentration of methacrylated gelatin is 10 wt% to 14 wt%, and the concentration of ZIF-8 loaded with catalase is not higher than 0.5 wt% and is not 0; In the prepolymer solution B, the concentration of the aldehyde-modified hyaluronic acid is 6 wt % to 10 wt %, and the concentration of the antibiotic is not higher than 0.05 wt % and is not 0; The prepolymer liquid A and the prepolymer liquid B are blended in equal masses.

6. The method for preparing the continuous oxygen supply / acid response root canal disinfection hydrogel according to claim 3, characterized in that: In the aldehyde formation of hyaluronic acid: hyaluronic acid is dissolved in water to form a hyaluronic acid solution, sodium periodate is added to the hyaluronic acid solution and stirred, and then ethylene glycol is added and stirred, and after terminating the reaction, dialyzed, frozen and dried to obtain the aldehyded hyaluronic acid.

7. The method for preparing the continuous oxygen supply / acid response root canal disinfection hydrogel according to claim 6, characterized in that: The concentration of the hyaluronic acid solution is 1.5wt%~2.5wt%; the amount of sodium periodate added is 0.5 times the amount of hyaluronic acid added; the amount of ethylene glycol added is equal to the amount of hyaluronic acid added.

8. The method for preparing the continuous oxygen supply / acid response root canal disinfection hydrogel according to claim 6 or claim 7, characterized in that: Add sodium periodate to the hyaluronic acid solution under light-proof conditions and stir for at least 20 hours; add ethylene glycol and stir for at least 1 hour; after terminating the reaction, dialyze in water for at least 60 hours.

9. The method for preparing the continuous oxygen supply / acid response root canal disinfection hydrogel according to claim 3, characterized in that: The steps of loading catalase in ZIF-8: Catalase: zinc nitrate hexahydrate: water are mixed and dissolved in a mass ratio of (0.03-0.05): (0.13-0.17): 5 to obtain solution X, 2-methylimidazole: anhydrous methanol are mixed and dissolved in a mass ratio of (0.30-0.35): 10 to obtain solution Y, solution X and solution Y are mixed and stirred to obtain a suspension, the suspension is centrifuged, the solid product is collected and washed and dried, and the catalase-loaded ZIF-8 is obtained.

10. Application of the continuous oxygen supply / acid response root canal disinfection hydrogel according to claim 1 or 2, characterized in that: Acts as a disinfectant in the root canal microenvironment.

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