An antibacterial hydrogel with photothermal triggered drug release properties, its preparation method and application

Abstract

This invention discloses an antibacterial hydrogel with photothermal-triggered drug release properties, its preparation method, and its applications. The antibacterial hydrogel comprises a hydrogel matrix material, mesoporous polydopamine-encapsulated sea urchin gold nanoparticles loaded onto the matrix material, and a carried antibacterial drug. The hydrogel is polymerized from aldehyde-modified hyaluronic acid and carboxymethyl chitosan, whose Schiff base bonds endow the hydrogel with excellent self-healing properties and stable mechanical properties. The loaded mesoporous polydopamine-encapsulated sea urchin gold nanoparticles can effectively carry the antibacterial drug and simultaneously possess a photothermal heating effect, endowing the hydrogel with excellent antibacterial properties. Controllable drug release can be achieved under near-infrared light irradiation, realizing the synergistic antibacterial effect of photothermal-drug interaction, effectively killing periodontal pathogens, inhibiting periodontal tissue loss, and improving periodontitis.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials technology, and in particular to an antibacterial hydrogel with photothermal triggered drug release properties, its preparation method, and its application. Background Technology

[0002] Periodontitis is a chronic, multifactorial disease associated with plaque buildup, characterized by progressive destruction of periodontal supporting tissues (including the periodontal ligament and alveolar bone). Symptoms such as gingival recession, halitosis, and tooth loss caused by periodontitis severely impact patients' chewing function and quality of life. Clinically, non-surgical mechanical plaque removal techniques such as supragingival scaling and root planing are commonly used to treat periodontitis; however, limitations in instruments result in less than ideal plaque removal in deep periodontal pockets and furcation areas. Adjunctive antibiotic therapy can control infection by killing or inhibiting the growth of periodontal pathogens. Minocycline, due to its antibacterial properties, ability to inhibit inflammatory factors, and capacity to promote periodontal tissue regeneration, is considered an effective agent for treating periodontal disease. However, long-term use of antibiotics may lead to multidrug resistance in bacteria, and may cause gastrointestinal side effects and drug allergic reactions. Furthermore, the drug concentration in periodontal pockets may be insufficient, affecting treatment efficacy.

[0003] In recent years, near-infrared (NIR) photothermal therapy has attracted much attention due to its excellent tissue penetration and photothermal conversion properties. Utilizing the surface plasmon resonance effect generated by the interaction between near-infrared light and gold nanomaterials, the local temperature can be increased, disrupting bacterial cell walls and achieving an antibacterial effect. Combining photothermal therapy with antibacterial drugs can reduce the dosage of medication and improve antibacterial efficiency.

[0004] Hydrogels possess excellent biocompatibility, good permeability, and adjustable degradation properties, making them promising local drug delivery systems for the treatment of periodontitis. However, traditional hydrogels are susceptible to structural damage from mechanical forces such as limb movements, and the loaded drugs are generally passively released, which may lead to insufficient drug release at the pharmacodynamic sites, preventing the drug from being released on demand.

[0005] Therefore, it is of great significance to develop an antibacterial hydrogel with photothermal-triggered drug release properties. It can improve antibacterial efficiency and reduce drug dosage through the synergistic effect of photothermal therapy and antibacterial drug bactericidal action, and can effectively kill periodontal pathogens. Summary of the Invention

[0006] The first objective of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a method for preparing an antibacterial hydrogel with photothermal triggered drug release properties.

[0007] The second objective of this invention is to provide an antibacterial hydrogel with photothermal-triggered drug release properties.

[0008] A third objective of this invention is to provide the application of the above-mentioned antibacterial hydrogel with photothermal triggered drug release properties.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] A method for preparing mesoporous polydopamine-encapsulated sea urchin gold nanoparticles includes the following steps:

[0011] S1. Preparation of silver seeds:

[0012] Hydroxylamine hydrochloride aqueous solution and sodium hydroxide aqueous solution were ultrasonically mixed to form a mixture. Then, silver nitrate aqueous solution was added and mixed thoroughly (to form a clear orange-yellow solution). After centrifugation, the supernatant was collected to obtain silver seeds.

[0013] S2. Preparation of sea urchin gold (UAu) nanoparticles:

[0014] Chloroauric acid aqueous solution was stirred at low temperature, and then the silver seeds prepared in step S1 were added. After the reaction, levodopa aqueous solution was added and the reaction continued. After the reaction was completed, the particles were centrifuged and dispersed in ultrapure water to obtain sea urchin gold nanoparticles, abbreviated as UAu.

[0015] S3. Preparation of mesoporous polydopamine-encapsulated sea urchin gold (UAu@MPDA) nanoparticles:

[0016] Dopamine hydrochloride and poloxamer were dissolved in a mixture of ethanol and ultrapure water and ultrasonically mixed. 1,3,5-trimethylbenzene was added and ultrasonically treated to form a microemulsion. The sea urchin gold nanoparticles prepared in step S2 were added and ultrasonically mixed again. Ammonia water was added to react. The reaction product was centrifuged, washed, and the particles were suspended in ultrapure water to obtain mesoporous polydopamine-encapsulated sea urchin gold nanoparticles, abbreviated as UAu@MPDA.

[0017] Further, the concentration of the hydroxylamine hydrochloride aqueous solution in step S1 is 1.5–2.0 mmol / L; preferably 1.7 mmol / L.

[0018] Further, the concentration of the sodium hydroxide aqueous solution in step S1 is 0.05–0.15 mol / L; preferably 0.1 mol / L.

[0019] Further, the ratio of hydroxylamine hydrochloride aqueous solution and sodium hydroxide aqueous solution in step S1 is 80-120 mL: 2-4 mL; preferably 100 mL: 3.3 mL.

[0020] Further, the concentration of the silver nitrate aqueous solution in step S1 is 8–12 mmol / L; preferably 10 mmol / L.

[0021] Further, the ratio of the mixture to the silver nitrate aqueous solution in step S1 is 7-11 mL: 0.5-2 mL; preferably 9 mL: 1 mL.

[0022] Further, the concentration of the chloroauric acid aqueous solution in step S2 is 6–15 mmol / L; preferably 10 mmol / L.

[0023] Further, the levodopa aqueous solution mentioned in step S2 is 0.8–1.2 mol / L; preferably 1.01 mol / L.

[0024] Further, the ratio of the chloroauric acid aqueous solution, silver seed solution, and levodopa aqueous solution in step S2 is 3-7 mL: 1-2 mL: 3-6 mL; preferably 5 mL: 1.8 mL: 4.8 mL.

[0025] Further, the stirring at low temperature in step S2 is stirring at 15±2℃ for 10±2 min; preferably, stirring in an ethanol water bath at 15℃ for 10 min.

[0026] Furthermore, the reaction time after adding silver seeds in step S2 is 1 ± 0.5 min.

[0027] Furthermore, the reaction time after adding the levodopa aqueous solution in step S2 is 15 ± 2 min.

[0028] Furthermore, the sea urchin gold nanoparticles added in step S3 are an aqueous solution of sea urchin gold nanoparticles with a concentration of 0.1 to 2.0 mg / mL; preferably, the aqueous solution of sea urchin gold nanoparticles with a concentration of 0.4 mg / mL.

[0029] Further, the ratio of dopamine hydrochloride, poloxamer, ethanol, ultrapure water, 1,3,5-trimethylbenzene, sea urchin gold nanoparticles, and ammonia in step S3 is 0.1–0.2 g: 0.05–0.2 g: 5 mL: 5 mL: 200–300 μL: 400–600 μL: 250–450 μL; preferably 0.15 g: 0.1 g: 5 mL: 5 mL: 250 μL: 500 μL: 375 μL.

[0030] Furthermore, the addition of ammonia in step S3 is carried out under centrifugal stirring conditions.

[0031] Furthermore, the reaction time in step S3 is 30 to 120 minutes; preferably 60 minutes.

[0032] An antibacterial hydrogel with photothermal triggered drug release properties was obtained by the above preparation method.

[0033] A method for preparing drug-loaded mesoporous polydopamine-encapsulated sea urchin gold nanoparticles involves dissolving minocycline (Mno) in an aqueous solution of the above-mentioned UAu@MPDA, ultrasonically mixing, stirring, centrifuging to remove the supernatant, washing and centrifuging the remaining mixture, and collecting the precipitate to obtain minocycline-loaded UAu@MPDA, abbreviated as Mno-UAu@MPDA.

[0034] Furthermore, the concentration of the aqueous solution of UAu@MPDA is 0.1–2.0 mg / mL, preferably 0.4 mg / mL.

[0035] Furthermore, the ratio of the aqueous solution of minocycline and UAu@MPDA is 0.5-2 mg: 8-12 mL, preferably 1 mg: 10 mL.

[0036] Furthermore, the stirring is carried out at room temperature (20–30°C).

[0037] Furthermore, the stirring time is 24±2h.

[0038] Furthermore, the stirring speed is 6000±500 r / min, and the stirring time is 6±2 min.

[0039] A drug-loaded mesoporous polydopamine-encapsulated sea urchin gold nanoparticle was prepared by the above method.

[0040] A method for preparing an antibacterial hydrogel with photothermal-triggered drug release properties (Mno-UAu@MPDA / Gel, abbreviated as Mno-UAM / Gel) involves dissolving aldehyde-modified hyaluronic acid and carboxymethyl chitosan separately in an aqueous solution of Mno-UAu@MPDA, mixing and vortexing the two solutions to obtain the antibacterial hydrogel with photothermal-triggered drug release properties, abbreviated as Mno-UAM / Gel.

[0041] Furthermore, the concentration of the aqueous solution of Mno-UAu@MPDA is 0.5–2.0 mg / mL; preferably 1.0 mg / mL.

[0042] Furthermore, the ratio of the aqueous solution of the aldehyde-modified hyaluronic acid and Mno-UAu@MPDA is 10-30 mg: 0.5-2 mL; preferably 20 mg: 1 mL.

[0043] Furthermore, the ratio of the aqueous solution of carboxymethyl chitosan and Mno-UAu@MPDA is 30-50 mg: 0.5-2 mL; preferably 40 mg: 1 mL.

[0044] Furthermore, the mixing ratio is a 1:1 volume ratio.

[0045] Furthermore, the aldehyde-modified hyaluronic acid is prepared by the following method: hyaluronic acid is dissolved in ultrapure water and stirred until completely dissolved. Sodium periodate aqueous solution is slowly added dropwise, and the reaction is allowed to proceed. Ethylene glycol is then added to terminate the reaction. The resulting reaction product is dialyzed and freeze-dried to obtain aldehyde-modified hyaluronic acid.

[0046] Furthermore, the concentration of the sodium periodate aqueous solution is 1–4 mmol / L; preferably 2.50 mmol / L.

[0047] Furthermore, the ratio of hyaluronic acid, ultrapure water, sodium periodate aqueous solution, and ethylene glycol is 0.5g~2g:100~300mL:3~6mL:1~3mL; preferably 1g:200mL:5mL:2mL.

[0048] Furthermore, the reaction is carried out under light-protected conditions for 2 ± 0.5 h.

[0049] Furthermore, the time for terminating the reaction is 1 ± 0.5 h.

[0050] The resulting photothermal antibacterial hydrogel exhibits excellent antibacterial activity, with a bactericidal rate of 99% against periodontal pathogens (Staphylococcus aureus, Escherichia coli, and Porphyromonas gingivalis).

[0051] An antibacterial hydrogel with photothermal triggered drug release properties was obtained by the above preparation method.

[0052] The above-mentioned antibacterial hydrogel with photothermal triggered drug release properties is used in the preparation of drugs for treating periodontitis.

[0053] Furthermore, the dosage form of the drug is an injection.

[0054] Technical Principle of the Invention: This invention provides an antibacterial hydrogel with photothermal-triggered drug release properties. This hydrogel is a Schiff base type hydrogel, composed of sea urchin gold nanoparticles encapsulated in mesoporous polydopamine loaded with the drug and a hydrogel matrix material. The hydrogel is polymerized from aldehyde-modified hyaluronic acid and amino-modified carboxymethyl chitosan; the dynamic covalent bonds formed between the two, i.e., Schiff base bonds, endow the hydrogel with excellent self-healing properties and stable mechanical properties. The sea urchin gold nanoparticles encapsulated in mesoporous polydopamine loaded in the hydrogel matrix material can serve as a drug carrier and simultaneously possess excellent photothermal conversion properties. Under near-infrared light irradiation, drug release can be regulated, achieving a combination of photothermal antibacterial and drug bactericidal effects, effectively killing periodontal pathogens.

[0055] The present invention has the following advantages and effects compared with the prior art:

[0056] (1) The antibacterial hydrogel Mno-UAM / Gel prepared in this invention has the characteristic of photothermal triggering the release of antibacterial drugs, which optimizes the current passive drug release method of drug-loaded materials, realizes the release of antibacterial drugs on demand, ensures the amount of drug released, and avoids the problem of insufficient local concentration of sustained-release drugs.

[0057] (2) The antibacterial hydrogel Mno-UAM / Gel prepared in this invention includes a hydrogel matrix material and Mno-UAu@MPDA loaded in the matrix material. It has both photothermal antibacterial and drug antibacterial effects, effectively killing periodontal pathogens while reducing the use of antibacterial drugs, avoiding bacterial resistance and adverse reactions caused by excessive use of antibacterial drugs in clinical practice.

[0058] (3) The antibacterial hydrogel Mno-UAM / Gel prepared in this invention is formed by the polymerization of aldehyde-modified hyaluronic acid and carboxymethyl chitosan. Its dynamic Schiff base bond endows the material with self-healing properties, so that the hydrogel can maintain a relatively stable structure and function when subjected to external force.

[0059] (4) The antibacterial hydrogel Mno-UAM / Gel prepared in this invention has excellent antibacterial properties. Under near-infrared light irradiation, it can achieve a 99% bactericidal rate against Staphylococcus aureus, Escherichia coli and Porphyromonas gingivalis. This hydrogel has good application prospects in eliminating periodontal pathogens. Attached Figure Description

[0060] Figure 1 This is a transmission electron microscope image (scale bar 200 nm) of UA prepared according to the present invention;

[0061] Figure 2 These are transmission electron microscope images of UAu@MDPA prepared in this invention;

[0062] Figure 3 This is a characterization diagram of the gelation properties of the Mno-UAM / Gel hydrogel prepared in this invention;

[0063] Figure 4 These are scanning electron microscope images of the Mno-UAM / Gel hydrogel prepared according to this invention;

[0064] Figure 5 This is a graph showing the changes in storage modulus G' and loss modulus G” of the Mno-UAM / Gel hydrogel prepared in this invention during strain scanning tests from 0.1% to 1000%.

[0065] Figure 6 This is a characterization diagram of the injectability of the Mno-UAM / Gel hydrogel prepared in this invention (image of the handwritten letters "JNU");

[0066] Figure 7 This is a characterization diagram of the self-healing ability of the Mno-UAM / Gel hydrogel prepared in this invention;

[0067] Figure 8 This is a graph showing the temperature changes of different concentrations of Mno-UAM / Gel hydrogels prepared in this invention within 10 minutes under near-infrared laser irradiation (808nm, 1.0W / cm2).

[0068] Figure 9 This is a release curve of minocycline from the Mno-UAM / Gel hydrogel prepared in this invention under photothermal triggering.

[0069] Figure 10 This is a cytotoxicity evaluation diagram of the Mno-UAM / Gel hydrogel prepared in this invention;

[0070] Figure 11 These are plate experiments showing Staphylococcus aureus treated in different experimental groups;

[0071] Figure 12 These are plate experiments of E. coli treated in different experimental groups;

[0072] Figure 13 These are plate experiment images of Porphyromonas gingivalis treated in different experimental groups;

[0073] Figure 14 This is a graph showing the temperature changes of suspensions of different concentrations of UA (0.1, 0.2, 0.3, 0.4, 0.5 mg / mL) over 10 minutes under 808 nm laser irradiation;

[0074] Figure 15 These are graphs characterizing the swelling ratio of gel hydrogels with different proportions;

[0075] Figure 16 These are rheological property characterization diagrams of gel hydrogels with different proportions;

[0076] Figure 17 This is a schematic diagram illustrating the preparation of the Mno-UAM / Gel hydrogel prepared according to the present invention and its application in periodontitis. Detailed Implementation

[0077] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0078] The Staphylococcus aureus used in the following examples is Staphylococcus aureus ATCC 25923;

[0079] The Escherichia coli (E. coli) used in the following examples is E. coli ATCC 25922.

[0080] The Porphyromonas gingivalis used in the following examples is Porphyromonas gingivalis BNCC236547.

[0081] Example 1

[0082] A method for preparing an antibacterial hydrogel with photothermal triggered drug release properties includes the following steps:

[0083] 1. Synthesis of mesoporous polydopamine-encapsulated sea urchin gold nanoparticles (UAu@MPDA), comprising the following steps:

[0084] (1) Preparation of sea urchin gold nanoparticles

[0085] Add 3.3 mL of 0.1 mol / L sodium hydroxide aqueous solution to 100 mL of hydroxylamine hydrochloride stock solution (i.e., 1.7 mmol / L hydroxylamine hydrochloride aqueous solution), and mix using an ultrasonic mixer for 1 min to prepare a mixture. Quickly add 1 mL of 10 mmol / L AgNO3 aqueous solution to 9 mL of the mixture and mix thoroughly (to obtain a clear orange-yellow solution). Centrifuge and collect the supernatant to obtain silver seeds. Add 5 mL of 0.01 mol / L chloroauric acid aqueous solution to a round-bottom flask and place it in an ethanol water bath at 15 °C with stirring for 10 min. Then add 1.8 mL of silver seeds and react for 1 min. Add 4.8 mL of 1.01 mol / L levodopa aqueous solution to the flask and react for 15 min. After the reaction is complete, add water and centrifuge, repeating 3 times. Dilute the supernatant to 4 mL per tube.

[0086] Figure 1 The image shows a TEM image of the prepared sea urchin gold. As can be seen from the image, the sea urchin gold nanoparticles are uniform and consist of a spherical core and multiple sharp tips growing from its surface. The average diameter of the spherical core is 78.02 nm and the average length of the spikes is 22.87 nm.

[0087] (2) Preparation of UAu@MPDA

[0088] Dissolve 0.15 g of dopamine hydrochloride (DA) and 0.1 g of poloxamer (Pluronic F127) in 10 mL of a 1:1 mixture of ethanol and ultrapure water, and mix thoroughly using ultrasound. At room temperature, add 250 μL of 1,3,5-trimethylbenzene (TMB) to the mixture and sonicate until a microemulsion forms. Then, add 500 μL of a 0.4 mg / mL sea urchin gold solution and continue sonicating. Under centrifugal stirring, add 375 μL of ammonia (NH3·H2O) to the mixture and react for 60 minutes. After the reaction, centrifuge for 5 minutes, wash with ethanol and acetone, repeating three times. Finally, suspend the washed sample in ultrapure water and bring the volume to 4 mL to obtain the UAu@MPDA solution.

[0089] Figure 2 The image shows a TEM image of the prepared UAu@MPDA. As can be seen from the image, the nanoparticles are uniform and have a core-shell structure with sea urchin gold as the core and mesoporous polydopamine as the shell. The thickness of the spherical polydopamine coating is 109.12 nm.

[0090] 2. The preparation method of Mno-UAu@MPDA particles includes the following steps:

[0091] Dissolve 1 mg of minocycline in 10 mL of 0.4 mg / mL UAu@MPDA solution using sonication. After homogeneous dissolution, stir for 24 hours at room temperature and in the dark, then centrifuge for 6 minutes (6000 rpm). Transfer the supernatant to a 5 mL centrifuge tube. Wash the remaining mixture with ultrapure water and centrifuge, repeating this process three times to separate the precipitate from the supernatant to obtain Mno-UAu@MPDA particles. Freeze-dry the sample and store for later use.

[0092] 3. Preparation of Aldehyde-Tylated Hyaluronic Acid (AHA)

[0093] Weigh 1g of hyaluronic acid (HA) into a 500mL round-bottom flask, add 200mL of ultrapure water, and place the flask on a digital display magnetic stirrer. Stir at 600rpm for at least 30min to completely dissolve the HA. Weigh 0.5347g of sodium periodate (NaIO4) in the dark, add 5mL of ultrapure water, and shake and stir to fully dissolve the NaIO4. Slowly add the NaIO4 solution dropwise to the round-bottom flask and react at 600rpm in the dark for 2h. Pipette 2mL of ethylene glycol into the round-bottom flask and terminate the reaction at 600rpm for 1h at room temperature. Purify the aldehyde-modified hyaluronic acid (AHA) stock solution by dialyzing it for 3 days using a dialysis bag (MWCO 14kDa) on a digital display magnetic stirrer at 600rpm, changing the water 3 times a day to remove unreacted components (NaIO4 and ethylene glycol). The obtained concentrate was freeze-dried, and the final white freeze-dried substance was the final sample freeze-dried AHA. The freeze-dried AHA was placed in a sealed bag and stored in a refrigerator at 4°C for later use.

[0094] 4. Preparation of antibacterial hydrogels (Mno-UAM / Gel) loaded with drugs and photothermal reagents

[0095] 20 mg of lyophilized AHA and 40 mg of carboxymethyl chitosan (CMCS) were dissolved in 1 mL of 1.0 mg / mL Mno-UAu@MPDA solution. The two solutions (1:1, v / v) were mixed, shaken, and vortexed for 60 s to obtain Mno-UAM / Gel hydrogel.

[0096] Figure 3 These are characterization images of the prepared Mno-UAM / Gel hydrogel before and after gelation. AHA is aldehyde-modified hyaluronic acid, CMCS is carboxymethyl chitosan, and Gel is a Schiff base hydrogel. As shown in the figure, AHA and CMCS exist in solution form, while Gel has formed a gel, indicating that the Schiff base hydrogel has been successfully prepared. Mno-UAM / Gel hydrogels can be prepared by dissolving AHA and CMCS separately in Mno-UAu@MPDA solution and then mixing them.

[0097] Figure 4 The image shows a SEM image of the prepared Mno-UAM / Gel hydrogel. As can be seen from the image, the hydrogel exhibits an irregular porous structure, with nanoparticles regularly distributed inside the hydrogel and on the surface pores.

[0098] 5. Characterization of the rheological and injectable properties of Mno-UAM / Gel hydrogel

[0099] (1) The frequency scanning conditions for the hydrogel were as follows: at a fixed frequency of 1 Hz, the changes in storage modulus G' (and loss modulus G”) were recorded under strains ranging from 0.1% to 1000%. The viscoelasticity of the hydrogel was measured by dynamic shear rotation at a fixed frequency of 1 Hz with shear rates ranging from 0.01 to 100 s⁻¹. -1 The range is characterized.

[0100] Figure 5 This section characterizes the shear-thinning properties of the Mno-UAM / Gel hydrogel prepared in this invention. As shown in the figure, the Mno-UAM / Gel hydrogel exhibits excellent viscoelasticity within the strain scanning range (0.1% to 1000%). When the hydrogel is subjected to a strain of 400%, the G' value decreases, and the G' value is less than the G” value, indicating that the Mno-UAM / Gel hydrogel possesses shear-thinning ability.

[0101] (2) The injectability of the Mno-UAM / Gel hydrogel was tested by continuously injecting it into a syringe with an inner diameter of Φ = 260 μm.

[0102] Figure 6 This section characterizes the injectability of the Mno-UAM / Gel hydrogel prepared according to the present invention. As shown in the figure, the Mno-UAM / Gel hydrogel exhibits excellent injectability, facilitating local periodontal drug administration.

[0103] (3) Prepare two Mno-UAM / Gel hydrogel samples (one hydrogel stained with methylene blue and one hydrogel stained with alizarin red), cut the two hydrogels in half and place them tightly together without applying any external action for 30 minutes.

[0104] Figure 7 This is a characterization of the self-healing ability of the Mno-UAM / Gel hydrogel prepared in this invention. As shown in the figure, the hydrogel fuses together at the cut site, exhibiting excellent self-healing properties.

[0105] 6. Photothermal properties of Mno-UAM / Gel hydrogel

[0106] Using a near-infrared laser (808nm 1.0W / cm) 2 Irradiate 1 mL of Mno-UAM / Gel at different concentrations (calculated based on Mno-UAu@MPDA concentrations, namely 0.5 mg / mL, 1.0 mg / mL, 1.5 mg / mL, and 2.0 mg / mL) for 10 min. During the irradiation, the hydrogel temperature is recorded using an infrared thermal imager (FLIR ONE Pro), with data recorded every 20 seconds.

[0107] Figure 8This figure characterizes the photothermal properties of the Mno-UAM / Gel hydrogel prepared in this invention under near-infrared laser irradiation. As shown in the figure, the photothermal heating behavior of Mno-UAM / Gel increases with the increase of Mno-UAu@MPDA concentration. When the concentration of Mno-UAM / Gel is 1 mg / mL (calculated based on Mno-UAu@MPDA concentration), the highest temperature of the Mno-UAM / Gel hydrogel after irradiation for 10 minutes reaches 57°C, while no significant temperature change was observed in the PBS group (control group), indicating that this invention can achieve controllable photothermal temperature.

[0108] 7. Drug release behavior test of Mno-UAM / Gel hydrogel

[0109] Using a near-infrared laser (808nm, 1.0W / cm²) 2 After irradiating 1 ml of Mno-UAM / Gel hydrogel for 5 min, it was immersed in PBS solution and placed at 37 °C and 100 rpm. -1 The samples were incubated in a shaker, and the supernatant was collected at 0.5h, 1h, 2h, 4h, 6h, 8h, 12h, 24h, 48h, 72h, 96h, and 120h. The absorbance of the antibacterial drug in the supernatant was measured at each time point, and the total release of minocycline was calculated to create a release curve. Three samples were repeated for each group.

[0110] Figure 9 This section characterizes the drug release performance of the Mno-UAM / Gel hydrogel prepared in this invention under photothermal triggering. As shown, the Mno-UAM / Gel+NIR group released more than 72% of minocycline within 72 hours, and continued to release it slowly during the subsequent degradation cycle. This indicates that the antibacterial hydrogel with photothermal triggering drug release performance possesses local drug sustained-release performance under NIR activation.

[0111] 8. Biocompatibility testing of Mno-UAM / Gel hydrogel

[0112] Gel hydrogel and Mno-UAM / Gel hydrogel were dissolved separately in DMEM tubes containing 10% FBS. The prepared hydrogels were sterilized with UV light for at least 2 hours. Then, 2 mL of DMEM containing 10% FBS was added to each tube, and the tubes were incubated at 37°C for 3 days. The hydrogel extract was filtered through a 0.22 μL aqueous membrane for subsequent CCK-8 assays. The in vitro cytotoxicity of the hydrogel was detected using hGFs. After culturing the cells, 100 μL of cell suspension at a density of approximately 5000 cells per well was added to each well of a 96-well plate, with 5 replicates per group. The plates were incubated for 24 hours (37°C, 5% CO2). After washing the cells with sterile PBS (0.01 M, pH 7.4), 20 μL of the hydrogel extract solution was added, and the plates were co-cultured for 24 hours. After washing the cells with sterile PBS (0.01 M, pH 7.4), CCK-8 medium was added, avoiding the formation of air bubbles. Incubate in the dark for 4 hours. Measure the absorbance at 450 nm using a microplate reader and determine the OD value.

[0113] Figure 10 This is a cytotoxicity evaluation diagram of the Mno-UAM / Gel hydrogel prepared in this invention. As shown in the figure, after treatment with the hydrogel for 24 hours, the extract showed a relative cell viability of approximately 93% compared to the control group, indicating that the Mno-UAM / Gel hydrogel exhibits ideal cell compatibility and can be safely used for subsequent periodontal treatment.

[0114] 9. In vitro photothermal antibacterial properties test of Mno-UAM / Gel hydrogel

[0115] The photothermal antibacterial activity of Mno-UAM / Gel hydrogel was evaluated using the plate diffusion method. Ten experimental groups were set up, including sterile PBS, sterile PBS+NIR, UAM, UAM+NIR, UAM / Gel, UAM / Gel+NIR, 5×Mno, 5×Mno+NIR, Mno-UAM / Gel, and Mno-UAM / Gel+NIR. 1 mL of the test sample was added to one of the three different bacterial suspensions (1×10⁻⁶). 5 In the sample containing CFU / mL (2 mL), NIR irradiation was then performed for 5 minutes (808 nm, 1.0 W / cm²) on samples requiring NIR irradiation (NIR(+)). 2After irradiation, the bacteria were co-incubated in a constant temperature incubator for 1 hour. After co-incubation, 100 μL of bacterial suspension from each treatment group in the *Staphylococcus aureus* and *Escherichia coli* groups was evenly spread onto LB agar plates and incubated at 37°C for 24 hours. For the *Porphyromonas gingivalis* group, 100 μL of bacterial suspension from each treatment group was evenly spread onto Columbia blood agar plates, placed in anaerobic bags, and then incubated statically at 37°C for 48 hours. After the incubation period, the colony counts were observed.

[0116] Figure 11 The figure shows the antibacterial characterization results of the prepared Mno-UAM / Gel hydrogel against Staphylococcus aureus. As shown in the figure, compared with the control group, the survival rate of Staphylococcus aureus was as low as 0.45% after NIR irradiation for 5 min, indicating that the Mno-UAM / Gel hydrogel has excellent antibacterial properties against Staphylococcus aureus.

[0117] Figure 12 The figure shows the antibacterial characterization results of the prepared Mno-UAM / Gel hydrogel against Escherichia coli. As shown in the figure, compared with the control group, the survival rate of Escherichia coli was as low as 0.43% after NIR irradiation for 5 min, indicating that the Mno-UAM / Gel hydrogel has excellent antibacterial properties against Escherichia coli.

[0118] Figure 13 The results of characterizing the antibacterial activity of the prepared Mno-UAM / Gel hydrogel against Porphyromonas gingivalis are shown in the figure. As shown in the figure, compared with the control group, the survival rate of Porphyromonas gingivalis was as low as 0.41% after 5 min of NIR irradiation, indicating that the Mno-UAM / Gel hydrogel has excellent antibacterial properties against Porphyromonas gingivalis.

[0119] Comparative Example 1

[0120] Sea urchin gold nanoparticles were prepared according to the method in Example 1. Solutions of sea urchin gold nanoparticles with concentrations of 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL, and 0.5 mg / mL were prepared, and diluted to 1 mL with ultrapure water and placed in EP tubes. The solutions were then subjected to 808 nm near-infrared laser light (1 W / cm²). 2 Irradiate continuously for 10 minutes, and record the temperature change every 20 seconds using an infrared thermal imager.

[0121] Figure 14The figure shows the temperature changes of UA suspensions at different concentrations (0.1, 0.2, 0.3, 0.4, and 0.5 mg / mL) under 808 nm laser irradiation over 10 minutes. As shown, the UA solution exhibits good photothermal conversion properties, and the rate and magnitude of temperature rise show a concentration-dependent relationship. UA solutions with concentrations above 0.3 mg / mL can raise the temperature by more than 40°C within 60 seconds, achieving a mild hyperthermia effect without causing mucosal burns. Considering the requirement to reduce operation time in oral clinical procedures and the impact of high concentrations on toxicity, a UA solution of 0.4 mg / mL is preferred.

[0122] Comparative Example 2

[0123] A 20% AHA solution was prepared and divided into five portions. CMCS solutions of 20%, 30%, 40%, 50%, and 60% were added to each portion, respectively, to prepare gel hydrogels with CMCS:AHA ratios of 1:1, 1.5:1, 2:1, 2.5:1, and 3:1. These hydrogels were then freeze-dried in an ultra-low temperature freezer, weighed (Wo), and immersed in 100 mL of neutral PBS solution at 37°C. At specified times (1, 2, 3, 4, 6, 8, 24, 48, and 72 h), the swollen hydrogels were removed, excess water was gently removed from the surface with filter paper, and the weight (Ws) was calculated. The dynamic storage modulus (G') and loss modulus (G″) of the hydrogels with different CMCS concentrations were measured at 37°C using a dynamic sweep frequency mode.

[0124] Figure 15 The figure shows the swelling ratios of different gel hydrogels. As shown, the swelling ratio of the gel hydrogel increases with the increase of CMCS content. Hydrogels with low swelling ratios can reduce physical pressure on periodontal pockets during oral applications.

[0125] Figure 16 The rheological diagrams of different gel hydrogels are shown in the figure. The gel hydrogel with a CMCS:AHA ratio of 2:1 exhibits the optimal cross-linking network. Considering the relationship between swelling ratio, rheological properties, and the amount of CMCS solution added, the hydrogel with a CMCS:AHA ratio of 2:1 is preferred.

[0126] Comparative Example 3

[0127] 20 mg of lyophilized AHA and 40 mg of carboxymethyl chitosan were dissolved in 1 mL of phosphate-buffered saline (PBS, pH 5.0), respectively, and labeled as Gel hydrogels. Mno-UAM / Gel hydrogels were prepared according to the method in Example 1, and their biocompatibility was compared with that of the Gel hydrogels. The specific steps are as follows: Gel hydrogels and Mno-UAM / Gel hydrogels were dissolved in 2 mL DMEM tubes containing 10% FBS and incubated at 37°C for 3 days. The hydrogel extract was filtered through a 0.22 μL aqueous phase membrane for subsequent CCK-8 assays. The in vitro cytotoxicity of the hydrogels was detected using human gingival fibroblasts (hGFs). After culturing the cells, 100 μL of cell suspension at a density of approximately 5000 cells per well was added to each well of a 96-well plate and incubated for 24 h (37°C, 5% CO2). After rinsing the cells with sterile PBS (0.01M, pH 7.4), add 20 μL of hydrogel extract solution and co-culture for 24 h. Then, rinse the cells with sterile PBS (0.01M, pH 7.4) and add them to CCK-8 medium, avoiding bubble formation. Incubate in the dark for 4 h. Measure the absorbance at 450 nm using a microplate reader to determine the OD value.

[0128] Figure 10 This is a cytotoxicity evaluation diagram of the Mno-UAM / Gel hydrogel prepared in this invention. As shown in the figure, after treatment with the hydrogel for 24 hours, the extract showed a relative cell viability of approximately 93% compared to the control group, indicating that the Mno-UAM / Gel hydrogel exhibits ideal cell compatibility and can be safely used for subsequent periodontal treatment.

[0129] Comparative Example 4

[0130] 20 mg of lyophilized AHA and 40 mg of carboxymethyl chitosan were dissolved in 1 mL of a 1.0 mg / mL UAu@MPDA solution, respectively, and labeled as UAM / Gel hydrogel. Mno-UAM / Gel hydrogel was prepared according to the method in Example 1. The antibacterial properties of the prepared hydrogel were compared with those of mesoporous polydopamine-encapsulated sea urchin gold (UAM) nanoparticles, minocycline (Mno), and UAM / Gel hydrogel. The specific steps are as follows: Ten experimental groups were set up, including sterile PBS, sterile PBS+NIR, UAM, UAM+NIR, UAM / Gel, UAM / Gel+NIR, 5×Mno, 5×Mno+NIR, Mno-UAM / Gel, and Mno-UAM / Gel+NIR. 1 mL of the sample to be tested was added to a Staphylococcus aureus suspension (1×10⁻⁶). 5 In the sample containing CFU / mL (2 mL), NIR irradiation was then performed for 5 minutes (808 nm, 1.0 W / cm²) on samples requiring NIR irradiation (NIR(+)).2 After irradiation, the samples were co-incubated in a constant temperature incubator for 1 hour. After co-incubation, 100 μL of bacterial suspension from each treatment group was evenly spread on LB agar plates and incubated at 37°C for 24 hours. After incubation, the colony count was observed.

[0131] Figure 11 The figure shows the antibacterial colony diagrams of Mno-UAM / Gel hydrogel, UAM nanoparticles, Mno, and UAM / Gel hydrogel against Staphylococcus aureus, and compares their antibacterial efficacy. As shown in the figure, after NIR irradiation, the bacterial survival rate of Staphylococcus aureus in the Mno-UAM / Gel hydrogel group decreased to 0.59%. The bacterial survival rates of 5×Mno, UAM, and UAM / Gel hydrogels were 12.48%, 60.15%, and 41.93%, respectively. The results indicate that the Mno-UAM / Gel hydrogel prepared in this invention has excellent antibacterial properties against Staphylococcus aureus.

[0132] Comparative Example 5

[0133] 20 mg of lyophilized AHA and 40 mg of carboxymethyl chitosan were dissolved in 1 mL of a 1.0 mg / mL UAu@MPDA solution, respectively, and labeled as UAM / Gel hydrogel. Mno-UAM / Gel hydrogel was prepared according to the method in Example 1. The antibacterial properties of the prepared hydrogel were compared with those of mesoporous polydopamine-encapsulated sea urchin gold (UAM) nanoparticles, minocycline (Mno), and UAM / Gel hydrogel. The specific steps are as follows: Ten experimental groups were set up, including sterile PBS, sterile PBS+NIR, UAM, UAM+NIR, UAM / Gel, UAM / Gel+NIR, 5×Mno, 5×Mno+NIR, Mno-UAM / Gel, and Mno-UAM / Gel+NIR. 1 mL of the sample to be tested was added to an E. coli suspension (1×10⁻⁶). 5 In the sample containing CFU / mL (2 mL), NIR irradiation was then performed for 5 minutes (808 nm, 1.0 W / cm²) on samples requiring NIR irradiation (NIR(+)). 2 After irradiation, the samples were co-incubated in a constant temperature incubator for 1 hour. After co-incubation, 100 μL of bacterial suspension from each treatment group was evenly spread on LB agar plates and incubated at 37°C for 24 hours. After incubation, the colony count was observed.

[0134] Figure 12The figure shows the antibacterial colony diagrams of Mno-UAM / Gel hydrogel, UAM nanoparticles, Mno, and UAM / Gel hydrogel against *Escherichia coli*, and compares their antibacterial efficacy. As shown in the figure, after NIR irradiation, the bacterial survival rate of *Staphylococcus aureus* in the Mno-UAM / Gel hydrogel group decreased to 1.08%. The bacterial survival rates of 5×Mno, UAM, and UAM / Gel hydrogels were 29.20%, 68.81%, and 42.60%, respectively. The results indicate that the Mno-UAM / Gel hydrogel prepared in this invention exhibits excellent antibacterial properties against *Escherichia coli*.

[0135] Comparative Example 6

[0136] 20 mg of lyophilized AHA and 40 mg of carboxymethyl chitosan were dissolved in 1 mL of a 1.0 mg / mL UAu@MPDA solution, respectively, and labeled as UAM / Gel hydrogel. Mno-UAM / Gel hydrogel was prepared according to the method in Example 1. The antibacterial properties of the prepared hydrogel were compared with those of mesoporous polydopamine-encapsulated sea urchin gold (UAM) nanoparticles, minocycline (Mno), and UAM / Gel hydrogel. The specific steps are as follows: Ten experimental groups were set up, including sterile PBS, sterile PBS+NIR, UAM, UAM+NIR, UAM / Gel, UAM / Gel+NIR, 5×Mno, 5×Mno+NIR, Mno-UAM / Gel, and Mno-UAM / Gel+NIR. 1 mL of the sample to be tested was added to a *Porphyromonas gingivalis* suspension (1×10⁻⁶). 5 In the sample containing CFU / mL (2 mL), NIR irradiation was then performed for 5 minutes (808 nm, 1.0 W / cm²) on samples requiring NIR irradiation (NIR(+)). 2 After irradiation, the samples were co-incubated in a constant temperature incubator for 1 hour. After co-incubation, 100 μL of bacterial suspension from each treatment group was evenly spread on Columbia blood agar plates, placed in anaerobic bags, and then placed in a 37°C constant temperature incubator for static incubation for 48 hours. After incubation, the colony count was observed.

[0137] Figure 13 The figure shows the antibacterial colony diagrams of Mno-UAM / Gel hydrogel, UAM nanoparticles, Mno, and UAM / Gel hydrogel against Escherichia coli, and compares their antibacterial efficacy. As shown in the figure, after NIR irradiation, the bacterial survival rate of Staphylococcus aureus in the Mno-UAM / Gel hydrogel group decreased to 0.97%. The bacterial survival rates of 5×Mno, UAM, and UAM / Gel hydrogels were 26.54%, 69.02%, and 41.03%, respectively. The results indicate that the Mno-UAM / Gel hydrogel prepared in this invention has excellent antibacterial properties against Porphyromonas gingivalis.

[0138] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing an antibacterial hydrogel with photothermal triggered drug release properties, characterized in that: Minocycline was dissolved in an aqueous solution of UAu@MPDA, ultrasonically mixed, stirred, centrifuged to remove the supernatant, the remaining mixture was washed and centrifuged, and the precipitate was collected to obtain UAu@MPDA loaded with minocycline, abbreviated as Mno-UAu@MPDA; Aldehyde-modified hyaluronic acid and carboxymethyl chitosan were dissolved in the aqueous solution of the obtained Mno-UAu@MPDA, respectively, and the two solutions were mixed at a volume ratio of 1:1, shaken and vortexed to obtain an antibacterial hydrogel with photothermal triggered drug release properties, abbreviated as Mno-UAM / Gel; The concentration of the aqueous solution of UAu@MPDA is 0.1–2.0 mg / mL; the ratio of the aqueous solution of minocycline and UAu@MPDA is 0.5–2 mg: 8–12 mL. The concentration of the aqueous solution of Mno-UAu@MPDA is 0.5–2.0 mg / mL; the ratio of the aqueous solution of aldehyde-modified hyaluronic acid and Mno-UAu@MPDA is 10–30 mg: 0.5–2 mL; the ratio of the aqueous solution of carboxymethyl chitosan and Mno-UAu@MPDA is 30–50 mg: 0.5–2 mL. The UAu@MPDA is prepared by a method including the following steps: S1. Preparation of silver seeds: Hydroxylamine hydrochloride aqueous solution and sodium hydroxide aqueous solution were ultrasonically mixed to form a mixture. Then, silver nitrate aqueous solution was added, and after thorough mixing and centrifugation, the supernatant was collected to obtain silver seeds. S2. Preparation of sea urchin gold nanoparticles: Chloroauric acid aqueous solution was stirred at 15±2℃, and then the silver seeds prepared in step S1 were added. After the reaction, levodopa aqueous solution was added and the reaction continued. After the reaction was completed, the particles were centrifuged and dispersed in ultrapure water to obtain sea urchin gold nanoparticles, abbreviated as UAu. S3. Preparation of mesoporous polydopamine-encapsulated sea urchin gold nanoparticles: Dopamine hydrochloride and poloxamer were dissolved in a mixture of ethanol and ultrapure water and ultrasonically mixed. 1,3,5-trimethylbenzene was added and ultrasonically treated to form a microemulsion. The sea urchin gold nanoparticles prepared in step S2 were added and ultrasonically mixed again. Ammonia water was added to react. The reaction product was centrifuged, washed, and the particles were suspended in ultrapure water to obtain mesoporous polydopamine-encapsulated sea urchin gold nanoparticles, abbreviated as UAu@MPDA.

2. The method for preparing the antibacterial hydrogel with photothermal triggered drug release properties according to claim 1, characterized in that: The concentration of the hydroxylamine hydrochloride aqueous solution mentioned in step S1 is 1.5–2.0 mmol / L; The concentration of the sodium hydroxide aqueous solution mentioned in step S1 is 0.05–0.15 mol / L; The ratio of hydroxylamine hydrochloride aqueous solution and sodium hydroxide aqueous solution mentioned in step S1 is 80-120 mL: 2-4 mL; The concentration of the silver nitrate aqueous solution mentioned in step S1 is 8–12 mmol / L; The ratio of the mixture to the silver nitrate aqueous solution in step S1 is 7-11 mL: 0.5-2 mL; The concentration of the chloroauric acid aqueous solution in step S2 is 6–15 mmol / L; The levodopa aqueous solution mentioned in step S2 is 0.8–1.2 mol / L; The ratio of chloroauric acid aqueous solution, silver seed solution, and levodopa aqueous solution in step S2 is 3-7 mL: 1-2 mL: 3-6 mL; The sea urchin gold nanoparticles added in step S3 are an aqueous solution of sea urchin gold nanoparticles with a concentration of 0.1–2.0 mg / mL. The ratio of dopamine hydrochloride, poloxamer, ethanol, ultrapure water, 1,3,5-trimethylbenzene, sea urchin gold nanoparticles and ammonia in step S3 is 0.1-0.2 g: 0.05-0.2 g: 5 mL: 5 mL: 200-300 μL: 400-600 μL: 250-450 μL.

3. The method for preparing the antibacterial hydrogel with photothermal triggered drug release properties according to claim 2, characterized in that: The concentration of the hydroxylamine hydrochloride aqueous solution mentioned in step S1 is 1.7 mmol / L; The concentration of the sodium hydroxide aqueous solution mentioned in step S1 is 0.1 mol / L; The ratio of hydroxylamine hydrochloride aqueous solution and sodium hydroxide aqueous solution mentioned in step S1 is 100 mL: 3.3 mL; The concentration of the silver nitrate aqueous solution mentioned in step S1 is 10 mmol / L; The ratio of the mixture to the silver nitrate aqueous solution in step S1 is 9 mL: 1 mL; The concentration of the chloroauric acid aqueous solution in step S2 is 10 mmol / L; The levodopa aqueous solution mentioned in step S2 is 1.01 mol / L; The ratio of chloroauric acid aqueous solution, silver seed solution, and levodopa aqueous solution in step S2 is 5 mL: 1.8 mL: 4.8 mL; The sea urchin gold nanoparticles added in step S3 are an aqueous solution of sea urchin gold nanoparticles with a concentration of 0.4 mg / mL. The ratio of dopamine hydrochloride, poloxamer, ethanol, ultrapure water, 1,3,5-trimethylbenzene, sea urchin gold nanoparticles and ammonia in step S3 is 0.15 g: 0.1 g: 5 mL: 5 mL: 250 μL: 500 μL: 375 μL; The stirring described in step S2 is stirring for 10 ± 2 min; The reaction time after adding silver seeds in step S2 is 1 ± 0.5 min; The reaction time after adding the levodopa aqueous solution in step S2 is 15 ± 2 min; The reaction time described in step S3 is 30 to 120 minutes.

4. The method for preparing the antibacterial hydrogel with photothermal triggered drug release properties according to claim 1, characterized in that: The concentration of the aqueous solution of UAu@MPDA is 0.4 mg / mL; The aqueous solution of minocycline and UAu@MPDA was prepared in a ratio of 1 mg: 10 mL. The stirring is carried out at 20–30°C; The stirring time is 24±2 h; The stirring speed is 6000±500 r / min, and the stirring time is 6±2 min.

5. The method for preparing the antibacterial hydrogel with photothermal triggered drug release properties according to claim 1, characterized in that: The concentration of the aqueous solution of Mno-UAu@MPDA is 1.0 mg / mL; The aqueous solution of the aldehyde-modified hyaluronic acid and Mno-UAu@MPDA was prepared in a ratio of 20 mg: 1 mL. The aqueous solution of carboxymethyl chitosan and Mno-UAu@MPDA was prepared in a ratio of 40 mg: 1 mL. The aldehyde-modified hyaluronic acid is prepared by the following method: hyaluronic acid is dissolved in ultrapure water and stirred until completely dissolved. Sodium periodate aqueous solution is slowly added dropwise to react. Then, ethylene glycol is added to terminate the reaction. The resulting reaction product is dialyzed and freeze-dried to obtain aldehyde-modified hyaluronic acid.

6. An antibacterial hydrogel with photothermal triggered drug release properties, characterized in that... It is obtained by the preparation method described in any one of claims 1-5.

7. The use of the antibacterial hydrogel with photothermal triggered drug release properties as described in claim 6 in the preparation of a medicament for treating periodontitis.

8. The application of the antibacterial hydrogel with photothermal triggered drug release properties according to claim 7 in the preparation of a drug for treating periodontitis, characterized in that: The drug is in the form of an injection.

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