A photocontrolled liquefaction hydrogel for inhibiting scar formation, its preparation method and application

Abstract

This invention belongs to the field of biomedical materials technology and discloses a photocontrolled liquefaction hydrogel that inhibits wound scar formation, its preparation method, and its application. The photocontrolled liquefaction hydrogel is composed of the following raw materials: 6-18 parts PVA hydrogel, 3-9 parts borax-boric acid buffer solution, and 1-3 parts PDA@CeO2-SAB nanoparticle suspension. The hydrogel of this invention has the characteristics of photocontrolled liquefaction, precise drug release, inhibition of CD36 expression, good biocompatibility, and biodegradability. It can be used for infected wounds, providing a new, simple, and effective material for inhibiting wound inflammation and promoting scar repair.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials technology, specifically relating to a light-controlled liquefaction hydrogel that inhibits scar formation on wounds, its preparation method, and its application. Background Technology

[0002] Wound healing involves four phases: coagulation, inflammation, proliferation, and remodeling. During the coagulation phase, platelets aggregate and produce PDGF (proliferative factor-dependent cytokine), which, along with bacterial products, recruits inflammatory cells to the injury site. These cells then accumulate and secrete pro-inflammatory cytokines, leading to the proliferation phase. Epidermal cells, fibroblasts, and vascular endothelial cells migrate, proliferate, and differentiate, forming granulation tissue. Finally, the granulation tissue matures and gradually transforms into a scar. Scar formation is a result of skin damage and can affect aesthetics, lead to decreased skin function, and cause psychological problems, including low self-esteem and anxiety. Therefore, researching how to better prevent scar formation, prevent skin function impairment, and improve skin appearance is crucial.

[0003] Scar formation is a complex physiological process involving the regulation of cell migration, inflammation, nerve innervation, and angiogenesis, characterized by persistent local inflammation and excessive collagen deposition. Current clinical treatments for scar prevention and treatment include surgical, non-surgical, and combined therapies, including intralesional or local steroids, cryotherapy, surgical excision, radiotherapy, and laser therapy for prevention. These therapies have high success rates and low recurrence rates, but are expensive and often accompanied by numerous adverse reactions. Therefore, developing an economical, safe, and effective drug delivery system to achieve scarless wound repair is of significant clinical importance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing clinical technologies and provide a light-controlled liquefaction hydrogel that inhibits scar formation, its preparation method, and its application. This hydrogel has the characteristics of light-controlled liquefaction, precise drug release, good biocompatibility, and biodegradability, and is used to inhibit scar formation after wound healing.

[0005] The technical solution of the present invention is as follows:

[0006] A photocontrolled liquefaction hydrogel for inhibiting scar formation, comprising, by volume, the following components:

[0007] 1–3 parts of PDA@CeO2-SAB nanoparticle suspension, 3–9 parts of borate-borax buffer solution with pH 8.2–8.6, and 6–18 parts of 5–10 wt% PVA hydrogel;

[0008] The concentration of the PDA@CeO2-SAB nanoparticle suspension is 160~200 μg / mL.

[0009] This invention also provides a method for preparing a photocontrolled liquefaction hydrogel that inhibits scar formation, comprising the following steps:

[0010] 1) Preparation of PDA@CeO2-SAB nanoparticle suspension;

[0011] 2) Prepare borate-borax buffer solution;

[0012] 3) Prepare PVA hydrogel;

[0013] 4) Mix the above materials evenly to obtain the light-controlled liquefaction hydrogel.

[0014] Furthermore, in step 1, the preparation steps of the PDA@CeO2-SAB nanoparticle suspension include:

[0015] 1A) Pluronic® F127, dopamine hydrochloride and 1,3,5-trimethylbenzene were dispersed in a mixture of water and ethanol, and an emulsion solution was formed by sonication. Ammonia was added dropwise to the reaction mixture under stirring to carry out oxidative self-polymerization. After the reaction was completed, the product was collected by centrifugation, and then washed several times with water and ethanol, and then resuspended in water to obtain a PDA nanoparticle suspension.

[0016] 1B) Add the Ce(NO3)3·6H2O aqueous solution to the PDA nanoparticle suspension prepared in 1A) above, stir to form a mixed solution, then add sodium hydroxide solution to the mixed solution to react, and after the reaction is completed, dialyze to obtain PDA@CeO2 nanoparticles.

[0017] 1C) The PDA@CeO2 nanoparticles prepared in 1B) above are uniformly mixed with salvianolic acid B, stirred for modification, washed with pure water and freeze-dried after the reaction to obtain PDA@CeO2-SAB nanoparticles, which are then resuspended in water to obtain a PDA@CeO2-SAB nanoparticle suspension.

[0018] Furthermore, in step 1A), the temperature for oxidative self-polymerization is 20~30℃, and the time is 1~3 hours;

[0019] In step 1B), the reaction temperature is 70~90℃ and the time is 5~10 hours;

[0020] In step 1C), the modification is carried out at a temperature of 20~30℃ for 20~30 hours.

[0021] Furthermore, in 1A), the mass ratio of Pluronic® F127 to dopamine hydrochloride is 4:3, and the volume ratio of 1,3,5-trimethylbenzene, water, and ethanol is 7:250:250; the volume ratio of water to ethanol during washing is 1:1.

[0022] Furthermore, in 1B), the concentration of Ce(NO3)3·6H2O aqueous solution is 4.60 mM, the concentration of PDA suspension is 0.38 mg / mL, the volume ratio of the two is approximately 1:7.5, and the concentration of sodium hydroxide solution is 0.1 M.

[0023] Furthermore, the preparation steps of borate-borax buffer solution in step 2) include:

[0024] 4.5 mL of 0.05 M borax solution and 5.5 mL of 0.05 M boric acid solution were mixed evenly to obtain a borate-borax buffer solution with a pH of 8.4, which was used as a crosslinking agent.

[0025] Furthermore, step 4) involves the preparation of the light-controlled liquefaction hydrogel, which includes:

[0026] (4A) First, mix 1 to 3 parts of PDA@CeO2-SAB nanoparticle suspension with 6 to 18 parts of 8% PVA hydrogel evenly, then add 3 to 9 parts of borate-borax buffer solution with pH 8.4 and mix evenly to make PDA@CeO2-SAB nanoparticles uniformly dispersed in the photocontrolled liquefaction hydrogel.

[0027] Compared with existing technologies, the photocontrolled liquefaction hydrogel of this invention, which inhibits scar formation, has the following advantages:

[0028] (1) The hydrogel of the present invention has good shape adaptability and adhesion. It can change shape according to irregular wound surface and adhere firmly to the wound surface without falling off, providing a moist repair environment for wound healing. The three-dimensional porous structure of the hydrogel is also conducive to oxygen penetration and absorption of tissue exudate, which helps to reduce the inflammatory response of the wound and promote wound healing.

[0029] (2) The PDA@CeO2-SAB nanoparticles selected in this invention have excellent photothermal properties. They can absorb 808 nm near-infrared light and convert light energy into heat energy. The generated heat energy can break the hydrogen bonds in the cross-linked network structure of the hydrogel, causing the hydrogel to liquefy and releasing the PDA@CeO2-SAB nanoparticles loaded within it, thus achieving precise drug release. In addition, the generated heat energy can also denature bacterial membrane proteins, thereby achieving photothermal antibacterial effects. Compared with traditional antibiotic antibacterial therapy, this method is more effective and has fewer side effects.

[0030] (3) Existing literature reports that c-JUN is highly expressed in scars, including hypertrophic scars and keloids. Epigenomic and transcriptomic analyses of human and mouse hypertrophic scar fibroblasts revealed that JUN induces fibrosis by regulating CD36. SAB or CD36 knockout models alleviated JUN-mediated wound fibrosis in humans and mice. In the PDA@CeO2-SAB nanoparticles used in this invention, SAB is an inhibitor of CD36, which can reduce the expression of CD36 protein in tissues and cells, thereby inhibiting scar formation. Attached Figure Description

[0031] Figure 1 The results are the light-controlled liquefaction performance test results for Examples 1, 2, 3, and 4.

[0032] Figure 2 The results are the biocompatibility test results of PCS PVA NIR in Example 6.

[0033] Figure 3 The results of the PCS PVA NIR inhibition of CD36 expression in 3T3 cells in Example 7 are shown.

[0034] Figure 4 The results of the test on the wound healing performance of PCS PVA NIR in Example 8 are shown. Detailed Implementation

[0035] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0036] To make the technical solution and advantages of the present invention clearer, the specific embodiments of the present invention will be described in detail below with reference to specific examples. Example 1

[0037] (1A) 0.2 g Pluronic® F127, 0.15 g dopamine hydrochloride, and 0.28 mL 1,3,5-trimethylbenzene were dispersed in a mixture of 10 mL water and 10 mL ethanol. The mixture was sonicated for 5 minutes to form an emulsion solution. Then, 0.75 mL ammonia was added dropwise to the reaction mixture while stirring. After reacting for 2 hours, the product was collected by centrifugation (15000 rpm, 10 minutes), washed several times with water and ethanol (1:1), and finally resuspended in water to obtain a PDA suspension.

[0038] (1B) 0.67 mL of 4.60 mM Ce(NO3)3·6H2O aqueous solution was added to 5.0 mL of 0.38 mg / mL PDA suspension. After stirring vigorously for 1 h, 0.06 mL of 0.1 M sodium hydroxide was rapidly added to the above mixed solution. The mixture was stirred at 80 °C for 6 h. Then, the obtained PDA@CeO2 nanoparticles were dialyzed (molecular weight cutoff: 14 kDa). After 24 hours, the liquid was collected to obtain PDA@CeO2 nanoparticles.

[0039] (1C) PDA@CeO2 nanoparticles and salvianolic acid B (SAB) were mixed uniformly at a mass ratio of 8:1, stirred for 24 hours and then freeze-dried to obtain PDA@CeO2-SAB nanoparticles.

[0040] (1D) Mix 4.5 mL of 0.05 M borax solution and 5.5 mL of 0.05 M boric acid solution evenly to obtain a borate-borax buffer solution with pH 8.4 as a crosslinking agent;

[0041] (1E) First, mix 0.2 mL of 80 μg / mL PDA@CeO2-SAB nanoparticles with 1.2 mL of 8% PVA hydrogel. Then, add 0.6 mL of borate-borax buffer solution with pH 8.4 and mix well to ensure that the PDA@CeO2-SAB nanoparticles are uniformly dispersed in the photocontrolled liquefaction hydrogel.

[0042] The preparation method of 80 μg / mL PDA@CeO2-SAB nanoparticles is as follows:

[0043] Dissolve 1 mg of PDA@CeO2-SAB nanoparticles in 1 mL of water, then add 80 μL of the solution and dilute with water to 1 mL.

[0044] The preparation method of 8% PVA hydrogel is as follows:

[0045] Weigh 4g of PVA powder and dissolve it in 50 mL of pure water. Example 2

[0046] (2A) Same as Example (1A);

[0047] (2B) Same as Example (1B);

[0048] (2C) Same as Example (1C);

[0049] (2D) Same as Example (1D);

[0050] (2E) The PDA@CeO2-SAB nanoparticles were 120 μg / mL, and the rest of the operation was the same as in Example (1E). Example 3

[0051] (3A) Same as Example (1A);

[0052] (3B) Same as Example (1B);

[0053] (3C) Same as Example (1C);

[0054] (3D) Same as Example (1D);

[0055] (3E) The PDA@CeO2-SAB nanoparticles were 160 μg / mL, and the rest of the operation was the same as in Example (1E). Example 4

[0056] (4A) Same as Example (1A);

[0057] (4B) Same as Example (1B);

[0058] (4C) Same as Example (1C);

[0059] (4D) Same as Example (1D);

[0060] (4E) The PDA@CeO2-SAB nanoparticles were 200 μg / mL, and the rest of the operation was the same as in Example (1E).

[0061] Example 5: Test of the photo-controlled liquefaction performance of photo-controlled liquefaction hydrogels

[0062] The photocontrolled liquefaction properties of the hydrogels were tested using the vial tilting method. Two mL of the photocontrolled liquefaction hydrogels from Examples 1, 2, 3, and 4 were added to each vial, with a power density of 1 W / cm³. 2 An 808 nm near-infrared laser was used to continuously irradiate the hydrogel for 15 minutes. An infrared thermal imager recorded the temperature changes of the hydrogel during these 15 minutes. After 15 minutes, the vial was tilted to observe the liquefaction of the hydrogel. Figure 1 As shown, after irradiation with an 808nm near-infrared laser for 15 minutes, the temperature of the hydrogel increased with the increase of the concentration of PDA@CeO2-SAB nanoparticles. The hydrogel group with 160 μg / mL PDA@CeO2-SAB nanoparticles had a temperature exceeding 40℃ after irradiation for 15 minutes, and the hydrogel began to show some liquefaction.

[0063] Example 6 Cell compatibility test of light-controlled liquefaction hydrogel

[0064] 1) Add 1 mL of the light-controlled liquefaction hydrogel prepared in Example 4 of this invention to 2 mL of complete culture medium containing 10% fetal bovine serum (FBS) and 1% penicillin / streptomycin. After incubation for 24 hours, aspirate the supernatant to obtain the light-controlled liquefaction hydrogel extract.

[0065] 2) Human umbilical vein endothelial cells (HUVECs) and mouse embryonic fibroblasts (3T3) were collected separately and seeded into 96-well plates at a rate of 10,000 cells per well. The cells were incubated with 100 μL of light-controlled liquefaction hydrogel extract for 24 hours. The old culture medium was then discarded, and the cells were washed three times with PBS. 100 μL of fresh culture medium and 10 μL of CCK-8 solution were added and incubated for 1 hour. The absorbance at 450 nm was measured using a microplate reader, and the relative cell viability was calculated.

[0066] 3) Culture the cells as described above, stain them with a cell viability / death staining kit (calcein AM / propidium iodide), and observe the cell viability / death status using a laser confocal microscope. The results are as follows: Figure 2 As shown, the Control group served as the control, with cell viability all above 80% and no obvious cytotoxicity. Cell liveness and deadness staining also showed that the cell morphology was normal and there were no obvious dead cells, indicating that the light-controlled liquefaction hydrogel prepared in this invention has good biocompatibility.

[0067] Example 7: Test of the performance of light-controlled liquefaction hydrogel in inhibiting CD36 expression in 3T3 cells

[0068] The ability of PCS PVA NIR to inhibit scar formation was verified by detecting the expression level of CD36 in 3T3 cells using immunofluorescence staining. Mouse embryonic fibroblasts (3T3) were collected and seeded at 80,000 cells per well into 12-well plates with pre-coated fibroblast covers. The cells were incubated with 1 mL of light-controlled liquefaction hydrogel extract for 24 hours. The old culture medium was then discarded, and the cell-coated covers were washed twice with PBS for 3 minutes each time. The covers were then fixed with 4% paraformaldehyde for 20 minutes and washed twice with PBS. After permeation with 0.5% Triton X-100 at room temperature for 15 minutes, the cell slides were removed from the well plate, fixed to the four corners with nail polish, and washed with PBS three times for 3 minutes each time. The PBS was then blotted dry with absorbent paper. 5% BSA (100 μL / slide) was added to the slide, and the slide was blocked at 37°C for 30 minutes. The blocking solution was then blotted off with absorbent paper. CD36 primary antibody (50 μL / slide) was added, and the slide was placed in a humidified chamber and incubated overnight at 4°C. The next day, the humidified chamber was removed, and the slide was allowed to return to room temperature for 1 hour. The slides were then washed three times with PBS for 3 minutes each time. Alexa Fluor 647-labeled goat anti-mouse secondary antibody (100 μL / slide) was added, and the slide was incubated at 37°C for 30 minutes. The slides were then washed three times with PBS for 3 minutes each time. The liquid on the slides was blotted dry with absorbent paper, and the slides were mounted with mounting medium containing DAPI (staining cell nuclei: blue) as an anti-fluorescence quencher. CD36 expression levels in 3T3 cells were observed under a laser confocal microscope, and the results are as follows: Figure 3 As shown, the Control group serves as the control group, from... Figure 3 It can be seen that after applying the hydrogel extract of Example 4, the expression level of CD36 in 3T3 cells decreased significantly, indicating that the light-controlled liquefaction hydrogel prepared in this invention has the ability to inhibit scar formation.

[0069] Example 8: Test on the wound healing performance of light-controlled liquefaction hydrogel

[0070] An acute wound infection model was established in male C57BL / 6 mice (5-6 weeks old, weighing 17-22g). The mice were divided into 6 groups (n=9 per group): Control group, PVA group, PVA NIR group, PDA@CeO2PVA NIR group (PC PVA NIR group), and PDA@CeO2-SAB PVA NIR group (PCS PVA NIR group). 1×10⁻⁶ PVA NIR was applied to the wound. 7CFU of Staphylococcus aureus solution was applied, covered with a 3M medical dressing, and bandaged. After 24 hours, appropriate drug treatment was administered. [Specific drug administration procedures for each group are as follows: Control group: the wound was covered with a 3M dressing and bandaged; PVA group: PVA was applied to the wound, covered with a 3M medical dressing, and bandaged; PVA NIR group: PVA was applied to the wound at 808 nm (1W / cm²).] 2 After 3 minutes of laser irradiation, apply a 3M medical dressing and bandage; PC PVA NIR group: Cover the wound with PC PVA at 808nm (1W / cm²). 2 After 3 minutes of laser irradiation, apply a 3M medical dressing and bandage; PCS PVA NIR group: apply PCS PVA to the wound at 808 nm (1W / cm²). 2 After 3 minutes of laser irradiation, a 3M medical dressing was applied and bandaged. Wound photographs were taken at days 0, 4, 7, 14, and 28 to determine wound size and calculate wound closure rate. On day 4, the wound area percentage in the Control group was 73.04%, and in the PCS PVA NIR group it was 6.48%. On day 7, the wound area percentage in the Control group was 34.06%, and in the PCS PVA NIR group it was 1.33%. On day 14, the wound area percentage in the Control group was 9.93%, and in the PCS PVA NIR group it was 0.93%. Figure 4 As can be seen from a and 4b, compared with the control group, the wound healing rate was faster in the hydrogel dressing group. Figure 4 c. It can be seen that the PCS PVA NIR hydrogel group healed the fastest after 808nm near-infrared light irradiation. Furthermore, on day 28, the scar area ratio in the Control group was 100%, while the wound area ratio in the PCS PVA NIR group was 0%. Figure 4 As can be seen, the wounds in the PCS PVA NIR hydrogel group also healed well, with smooth skin tissue and no scar formation after healing. This indicates that the PCS PVA NIR hydrogel of the present invention has the effect of promoting wound repair and preventing scar formation.

[0071] This invention provides a method for preparing and applying a light-controlled liquefaction hydrogel that inhibits CD36 to achieve scar repair in wounds. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

[0072] This invention belongs to the field of biomedical materials technology and discloses a light-controlled liquefaction hydrogel that inhibits wound scar formation, its preparation method, and its application. The light-controlled liquefaction hydrogel is composed of the following raw materials: 6-18 parts PVA hydrogel, 3-9 parts borax-boric acid buffer, and 1-3 parts PDA@CeO2-SAB nanoparticles. The hydrogel of this invention has the characteristics of light-controlled liquefaction, precise drug release, inhibition of CD36 expression, good biocompatibility, and biodegradability. It can be used for infected wounds and provides a new, simple, and effective material for inhibiting wound inflammation and promoting scar repair.

Claims

1. A photo-controllable liquefiable hydrogel for inhibiting scar formation, characterized by, By volume, comprising the following components: 1-3 parts of PDA@CeO2-SAB nanoparticle suspension, 3-9 parts of pH 8.2-8.6 borate buffer and 6-18 parts of 5-10wt% PVA hydrogel; The concentration of the PDA@CeO2-SAB nanoparticle suspension is 200 μg / mL; The mixing order of the above components is as follows: first, the PDA@CeO2-SAB nanoparticle suspension and the PVA hydrogel are stirred and mixed uniformly, then the borate buffer is added and stirred uniformly to obtain the photo-controlled liquefied hydrogel; The PDA@CeO2-SAB nanoparticle suspension is prepared by the following method: 1A) Pluronic® F127, dopamine hydrochloride and 1,3,5-trimethylbenzene are dispersed in a mixture of water and ethanol, an emulsion solution is formed by ultrasonic, ammonia water is added dropwise to the reaction mixture under stirring for oxidative self-polymerization, the product is collected by centrifugation after the reaction is completed, then washed with water and ethanol for several times, then resuspended with water to obtain a PDA nanoparticle suspension; 1B) Ce(NO3)3·6H2O aqueous solution is added to the PDA nanoparticle suspension prepared in 1A) above, a mixed solution is formed by stirring, then sodium hydroxide solution is added to the above mixed solution for reaction, dialysis is performed after the reaction is completed to obtain PDA@CeO2 nanoparticles; 1C) The PDA@CeO2 nanoparticles prepared in 1B) above are uniformly mixed with salvianolic acid B, stirring is performed for modification of salvianolic acid B, after the reaction is completed, water washing and freeze-drying are performed to obtain PDA@CeO2-SAB nanoparticles, which are resuspended with water to obtain a PDA@CeO2-SAB nanoparticle suspension.

2. A method of preparing a photoresponsive liquefiable hydrogel according to claim 1, wherein Comprising the following steps: 1) Preparation of PDA@CeO2-SAB nanoparticle suspension; 2) Preparation of borate buffer; 3) Preparation of PVA hydrogel; 4) The above materials are uniformly stirred and mixed to obtain the photo-controlled liquefied hydrogel.

3. The method of claim 2, wherein the photoresponsive liquefiable hydrogel is prepared by the steps of: In step 1), the preparation steps of the PDA@CeO2-SAB nanoparticle suspension include: 1A) Pluronic® F127, dopamine hydrochloride and 1,3,5-trimethylbenzene are dispersed in a mixture of water and ethanol, an emulsion solution is formed by ultrasonic, ammonia water is added dropwise to the reaction mixture under stirring for oxidative self-polymerization, the product is collected by centrifugation after the reaction is completed, then washed with water and ethanol for several times, then resuspended with water to obtain a PDA nanoparticle suspension; 1B) Ce(NO3)3·6H2O aqueous solution is added to the PDA nanoparticle suspension prepared in 1A) above, a mixed solution is formed by stirring, then sodium hydroxide solution is added to the above mixed solution for reaction, dialysis is performed after the reaction is completed to obtain PDA@CeO2 nanoparticles; 1C) The PDA@CeO2 nanoparticles prepared in 1B) above are uniformly mixed with salvianolic acid B, stirring is performed for modification of salvianolic acid B, after the reaction is completed, water washing and freeze-drying are performed to obtain PDA@CeO2-SAB nanoparticles, which are resuspended with water to obtain a PDA@CeO2-SAB nanoparticle suspension.

4. The method for preparing the photo-controlled liquefied hydrogel according to claim 3, characterized in that, in step 1A), the temperature for the oxidation self-polymerization is 20-30 ℃, and the time is 1-3 hours; in step 1B), the reaction temperature is 70-90 ℃, and the time is 5-10 hours; in step 1C), the temperature for the modification is 20-30 ℃, and the time is 20-30 hours. In step 2), the boric acid-borax buffer solution is obtained by uniformly mixing 0.04-0.06 M borax solution and 0.04-0.06 M boric acid solution. The volume ratio of the borax solution and the boric acid solution is 4-5:5-6. In step 4), the volume ratio of each component is PDA@CeO2-SAB nanoparticle suspension:boric acid-borax buffer solution:PVA hydrogel = 1:3:

6.

5. The method of claim 2, wherein the photoresponsive liquefiable hydrogel is prepared by the steps of: In step 4), the mixing order of each component is: first, the PDA@CeO2-SAB nanoparticle suspension is uniformly mixed with the PVA hydrogel by stirring, and then the boric acid-borax buffer solution is added and uniformly stirred to obtain the photo-controlled liquefied hydrogel. The photo-controlled liquefied hydrogel is used for preparing a medical material for promoting the repair of infected wounds.

6. The method of claim 2, wherein the photocontrolling the liquefaction of the hydrogel is performed by irradiating the hydrogel with a laser beam. The medical material is used for anti-scarring repair of acute infected wounds.

7. The method for preparing the light-controlled liquefaction hydrogel according to claim 2, characterized in that, ​ 8. Use of a photoresponsive liquefiable hydrogel according to claim 1 or a photoresponsive liquefiable hydrogel obtained by the method according to any one of claims 2 to 7, characterized in that, ​ 9. Use according to claim 8, characterized in that, ​

Images