A method for preparing a multifunctional hydrogel dressing that can be positioned and contracted at a point
By using photopolymerization 3D printing and freeze-thaw cycle technology, a multifunctional hydrogel dressing was prepared, which solved the problems of adaptability and single function of traditional hydrogel dressings, and achieved targeted and directional shrinkage of irregular wounds and multiple performance improvements.
Patent Information
- Application Number
- CN202610846168.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-12
- Publication Date
- 2026-07-14
Smart Images
Figure CN122376832A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of medical biomaterials technology, specifically relating to a method for preparing a multifunctional hydrogel dressing that can be positioned and contracted at specific points. Background Technology
[0002] Hydrogel dressings are widely used in wound care due to their high water content, good biocompatibility, and extracellular matrix-like structure. However, traditional hydrogel dressings still have significant shortcomings in practical applications: on the one hand, ordinary hydrogel dressings lack adaptability to wound shapes, especially for irregularly shaped wounds or wounds under dynamic tension, making it difficult to achieve close adhesion and directional closure traction; on the other hand, existing hydrogels have relatively limited functions and cannot simultaneously meet multiple clinical needs such as antibacterial properties, controlled contraction, and mechanical matching.
[0003] Among numerous smart materials, thermoresponsive polymers (such as poly(N-isopropylacrylamide) have attracted attention due to their reversible volume phase transition around 32-34°C. However, hydrogels based on poly(N-isopropylacrylamide) exhibit poor mechanical properties and their shrinkage behavior is mostly isotropic random aggregation, making it impossible to achieve targeted, directional, and graded shrinkage in specific wound areas. Furthermore, while introducing functional nanomaterials (such as MXene) can improve antibacterial and electrical conductivity, ensuring their uniform dispersion in the gel matrix and their synergistic compatibility with different crosslinking systems remains a technical challenge. Summary of the Invention
[0004] To address the problems raised in the background art, the present invention provides a method for preparing a multifunctional hydrogel dressing that can be positioned and contracted at specific points.
[0005] The technical solution of the present invention is as follows: This invention provides a method for preparing a multifunctional hydrogel dressing that can be positioned and contracted at specific points, comprising: Step 1: Mix phosphate buffer solution with polyvinyl alcohol and heat to obtain polyvinyl alcohol solution; Step 2: Under light-protected conditions, mix phosphate buffer solution, N-isopropylacrylamide, N,N'-methylenebisacrylamide, and phenyl (2,4,6-trimethylbenzoyl) lithium phosphate to obtain a mixture; Step 3: Mix the polyvinyl alcohol solution with the mixed liquid, add MXene dispersion, and sonicate to obtain a composite solution; Step 4: After setting the printing and lighting parameters, the hydrogel is formed by photopolymerization 3D printing using a composite solution as the printing ink, following the preset pattern path. Step 5: The hydrogel is subjected to freeze-thaw cycles to obtain a hydrogel dressing.
[0006] Based on the above-described method for preparing a multifunctional hydrogel dressing with localized and targeted shrinkage, in step 3, the mass ratio of polyvinyl alcohol to N-isopropylacrylamide in the composite solution is 0.8-1.2:1, the mass ratio of N-isopropylacrylamide to N,N'-methylenebisacrylamide is 1:0.025-0.035, and the mass ratio of N-isopropylacrylamide to phenyl (2,4,6-trimethylbenzoyl)lithium phosphate is 1:0.025-0.035.
[0007] Furthermore, the mass ratio of MXene material to N-isopropylacrylamide is 1:250-1:1000.
[0008] Based on the above-described method for preparing a multifunctional hydrogel dressing with targeted shrinkage, step 4 is specifically performed as follows: Step 41: Create a 3D model based on the shape of the wound, dividing it into loose area, dense area and transition area; Step 42: Set the spacing between the print lines in each zone and generate the print path; Step 43: Using the composite solution as printing ink, print layer by layer according to the printing path, and cure the shape by ultraviolet light.
[0009] Furthermore, step 42 generates the print path, including: Step a: Under fixed lighting parameters, print test lines with different designed line widths, measure the actual line width, establish the first mapping model between the designed line width and the actual line width, and at the same time establish the second mapping model between the actual line width and the shrinkage rate; Step b: After determining the target shrinkage rates of the loose zone, dense zone, and transition zone, determine the target actual linewidth based on the target shrinkage rate and the second mapping model; determine the target design linewidth based on the target actual linewidth and the first mapping model. Step c: Generate the printing path for each area based on the target line width and line spacing.
[0010] Furthermore, the illumination time for each layer is 10 seconds, and the light intensity is 10 mW / cm². 2 .
[0011] Based on the above-described method for preparing a multifunctional hydrogel dressing with locatable and point-contact shrinkage, the line spacing in step 42 is determined according to the target shrinkage rate of each zone.
[0012] Furthermore, the printing line spacing in the loose area is 1.0-1.5mm, and the printing line spacing in the dense area is 0.2-0.5mm.
[0013] Furthermore, the printing line spacing in the transition zone is 0.5-1.0mm.
[0014] Based on the above-described method for preparing a multifunctional hydrogel dressing with locatable and point-contraction capabilities, in step 4, the preset pattern includes radial, concentric circle, grid, parallel line, or biomimetic fractal structures.
[0015] Beneficial effects This invention utilizes the thermally responsive volumetric phase transition behavior of poly(N-isopropylacrylamide) to aid in wound exudate management and active debridement. Polyvinyl alcohol exhibits good biocompatibility, and the addition of MXene endows the hydrogel with antibacterial and electrical properties. Based on this, the hydrogel is prepared by using photopolymerization 3D printing to rapidly crosslink N-isopropylacrylamide, forming a stable covalent crosslinked network that immobilizes MXene and polyvinyl alcohol. Subsequently, freeze-thaw cycles are used to form a physical crosslinked network, thereby enhancing the mechanical properties of the hydrogel and regulating its thermally responsive shrinkage behavior.
[0016] This invention achieves differentiated shrinkage in terms of positioning, location, and direction by programming and controlling the structure. It can design hydrogels suitable for wound closure according to various wound shapes. The hydrogels have good shrinkage, biocompatibility, antibacterial properties, conductivity, and mechanical stability. Attached Figure Description
[0017] Figure 1 The above are the preset patterns of the present invention, where a is a microscopic image of the 3D printed hydrogel and b is a 3D model with different designs.
[0018] Figure 2 These are the mechanical property test results of the hydrogel dressing of the present invention, where a is PPM. 100 PPM 200 PPM 400 The compressive stress-strain curve, where b is the compressive modulus and c is the PPM. 400 30 compression cycles, d is in PPM 100 PPM 200 PPM 400 The tensile stress-strain curve, where e is Young's modulus and f is PPM. 400 30 stretching cycles, g is PPM 400 A schematic diagram of adhesion.
[0019] Figure 3 In Figure a, live / dead fluorescent staining images of fibroblasts on days 1, 3, and 5 are shown. In Figure b, cell proliferation of fibroblasts on days 1, 3, and 5 is shown. * and ns represent significance markers. In Figure c, hemolysis of the hydrogel dressing is visualized. In Figure d, hemolysis rate of the hydrogel dressing is shown.
[0020] Figure 4The results of the antibacterial performance test of the hydrogel dressing of the present invention are shown, where a represents the concentrations of Staphylococcus aureus and Escherichia coli at PPM, respectively. 400 Photographs of bacterial colonies under hydrogel co-culture, where b represents the antibacterial rate of the hydrogel.
[0021] Figure 5 In the diagram, a represents the electrical resistance and conductivity of the hydrogel, b represents the strain-resistance response curve, and c represents the PPM. 400 The hydrogel's response curves after 100 cycles at 20% strain are shown in Figure d. d represents the electrical signal curves when the finger is bent at 30°, 60°, and 90°. e represents the electrical curves of the wrist at different flexion speeds. f represents the characteristic electrical curve of the elbow flexion.
[0022] Figure 6 a, b, and c represent PPMs designed in different shapes. 400 The thermal shrinkage rate of different regions of the hydrogel is shown in the figure. Regions 1, 2, and 3 represent different regions. Detailed Implementation
[0023] The following examples are intended to illustrate the present invention, and not to further limit the invention.
[0024] This invention provides a method for preparing a multifunctional hydrogel dressing that can be positioned and contracted at specific points, comprising: Step 1: Mix phosphate buffer solution with polyvinyl alcohol and heat to obtain polyvinyl alcohol solution; Step 2: Under light-protected conditions, mix phosphate buffer solution, N-isopropylacrylamide, N,N'-methylenebisacrylamide, and phenyl (2,4,6-trimethylbenzoyl) lithium phosphate to obtain a mixture; Step 3: Mix the polyvinyl alcohol solution with the mixed liquid, add MXene dispersion, and sonicate to obtain a composite solution; Step 4: After setting the printing and lighting parameters, the hydrogel is formed by photopolymerization 3D printing using a composite solution as the printing ink, following the preset pattern path. Step 5: The hydrogel is subjected to freeze-thaw cycles to obtain a hydrogel dressing.
[0025] Based on the above-described method for preparing a multifunctional hydrogel dressing with localized and targeted shrinkage, in step 3, the mass ratio of polyvinyl alcohol to N-isopropylacrylamide in the composite solution is 0.8-1.2:1, the mass ratio of N-isopropylacrylamide to N,N'-methylenebisacrylamide is 1:0.025-0.035, and the mass ratio of N-isopropylacrylamide to phenyl (2,4,6-trimethylbenzoyl)lithium phosphate is 1:0.025-0.035.
[0026] Furthermore, the mass ratio of MXene material to N-isopropylacrylamide is 1:250-1:1000.
[0027] This invention utilizes the thermally responsive volumetric phase transition behavior of poly(N-isopropylacrylamide) to aid in wound exudate management and active debridement. Polyvinyl alcohol exhibits good biocompatibility, and the addition of MXene endows the hydrogel with antibacterial and electrical properties. During the preparation process, photopolymerization 3D printing rapidly crosslinks N-isopropylacrylamide, forming a stable covalent crosslinked network that immobilizes MXene and polyvinyl alcohol. Subsequently, freeze-thaw cycles are used to form a physical crosslinked network, thereby enhancing the mechanical properties of the hydrogel and regulating its thermally responsive shrinkage behavior.
[0028] Based on the above-described method for preparing a multifunctional hydrogel dressing with locatable and point-constricted shrinkage, in step 4, the preset pattern includes a grid pattern, a radial pattern, a concentric circle pattern, a parallel line pattern, or a biomimetic fractal structure. For example... Figure 1 As shown.
[0029] Based on the above-described method for preparing a multifunctional hydrogel dressing with targeted shrinkage, step 4 is specifically performed as follows: Step 41: Create a 3D model based on the shape of the wound, dividing it into loose area, dense area and transition area; Step 42: Set the spacing between the print lines in each zone and generate the print path; Step 43: Using the composite solution as printing ink, print layer by layer according to the printing path, and cure the shape by ultraviolet light.
[0030] Based on the above-described method for preparing a multifunctional hydrogel dressing with locatable and point-contact shrinkage, the line spacing mentioned in step 42 is determined according to the target shrinkage rate of each zone. This can be achieved by calibrating the mapping relationship between line spacing and shrinkage rate through preliminary experiments, or by finite element simulation calculations.
[0031] Preferably, the printing line spacing in the loose area is 1.0-1.5mm, and the printing line spacing in the dense area is 0.2-0.5mm.
[0032] Furthermore, the printing line spacing in the transition zone is 0.5-1.0mm.
[0033] This invention establishes a 3D model based on the wound shape and divides it into loose, dense, and transitional zones. Combined with differentiated line spacing settings, the hydrogel dressing can generate graded shrinkage according to preset areas under temperature stimulation, overcoming the technical defects of isotropic random aggregation of traditional poly(N-isopropylacrylamide) hydrogels.
[0034] In photopolymer 3D printing, the actual line width is not simply equal to the design width. It is influenced by a combination of factors, including light intensity, exposure time, ink formulation, and light scattering effects, resulting in a non-linear deviation. If printing is performed directly according to the ideal line width design model, the final physical line width often deviates from the expectation, leading to uncontrolled shrinkage rates in subsequent processes.
[0035] Furthermore, step 42 generates the print path, including: Step a: Under fixed lighting parameters, print test lines with different designed line widths, measure the actual line width, establish the first mapping model between the designed line width and the actual line width, and at the same time establish the second mapping model between the actual line width and the shrinkage rate; Step b: After determining the target shrinkage rates of the loose zone, dense zone, and transition zone, determine the target actual linewidth based on the target shrinkage rate and the second mapping model; determine the target design linewidth based on the target actual linewidth and the first mapping model. Step c: Generate the printing path for each area based on the target line width and line spacing.
[0036] Furthermore, the illumination time for each layer is 10 seconds, and the light intensity is 10 mW / cm². 2 .
[0037] Furthermore, regarding the first and second mapping models, a series of test lines with different designed linewidths (0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, and 0.8mm) were printed by collecting process parameters such as ink formulation, light intensity, exposure time, and ambient temperature. The actual cured linewidths corresponding to each designed linewidth were measured, and a first mapping model between the designed and actual linewidths was established. Next, the lines with the different actual linewidths were arranged into 10mm × 10mm grid samples at a fixed spacing (1.0mm), incubated in a phosphate buffer solution at 37℃ for 30 minutes, and the dimensions of each sample after shrinkage were measured. The shrinkage rate was calculated, and a second mapping model between the actual linewidth and the shrinkage rate was established. Based on the target shrinkage rate, the required actual linewidth was deduced from the second mapping model, and then the designed linewidth was deduced from the first mapping model, thus generating the printing path for each region.
[0038] This invention establishes a mapping model by fixing illumination parameters and conducting calibration experiments under those parameters beforehand. Without decoupling complex photochemical processes, it can accurately calculate the design linewidth required to achieve the target shrinkage rate simply by inversely solving these two mapping relationships. This eliminates the need for complex and difficult-to-control parameter switching during printing, making it suitable for customized intelligent dressing manufacturing scenarios.
[0039] This invention achieves differentiated shrinkage in terms of positioning, location, and direction by programming and controlling the structure. It can design hydrogels suitable for wound closure according to various wound shapes. The hydrogels have good shrinkage, biocompatibility, antibacterial properties, conductivity, and mechanical stability.
[0040] Example 1 This embodiment provides a method for preparing a multifunctional hydrogel dressing that can be positioned and contracted at specific points, including: Step 1: Add 2g of polyvinyl alcohol to 10mL of phosphate buffer solution, heat and stir in an oil bath at 90℃ until completely dissolved to obtain a polyvinyl alcohol solution.
[0041] Step 2: Add 2g of N-isopropylacrylamide, 60mg of N,N'-methylenebisacrylamide, and 60mg of phenyl (2,4,6-trimethylbenzoyl) lithium phosphate to 10mL of phosphate buffer solution in sequence, and stir until completely dissolved under light-protected conditions to obtain a mixture.
[0042] Step 3: The volume ratio of polyvinyl alcohol solution to the mixed solution is 1:1. Then, MXene dispersion is added to the solution at MXene concentrations of 100 μg / ml, 200 μg / ml, and 400 μg / ml, respectively. The mixture is then sonicated to obtain three composite solutions with different MXene concentrations. The MXene dispersion is Ti3C2T. x Aqueous dispersion of MXene.
[0043] Step 4: After setting the printing and lighting parameters, follow the preset pattern path, using the composite solution as the printing ink, and obtain the hydrogel through photopolymerization 3D printing. The operation is as follows: Step 41: Create a 3D model based on the shape of the wound, dividing it into loose area, dense area and transition area.
[0044] Step 42: Set the spacing between print lines in each zone and generate the print path. This includes: Step a: Under fixed lighting parameters, print test lines with different designed line widths, measure the actual line widths, establish a first mapping model between the designed line width and the actual line width, and at the same time establish a second mapping model between the actual line width and the shrinkage rate.
[0045] Step b: After determining the target shrinkage rates of the loose zone, dense zone, and transition zone, determine the target actual line width based on the target shrinkage rate and the second mapping model; determine the target design line width based on the target actual line width and the first mapping model; and determine the printing line spacing for each zone based on the target shrinkage rate.
[0046] Step c: Generate the printing path for each area based on the target line width and line spacing.
[0047] In this embodiment, the line spacing in the loose area is 1.1 mm, the line spacing in the dense area is 0.2 mm, and the line spacing in the transition area is 0.8 mm. The target design line width is 0.4 mm.
[0048] Step 43: Using the composite solution as printing ink, print layer by layer according to the printing path, and cure the layer by layer with ultraviolet light. The light exposure time for each layer is 10 seconds, and the light intensity is 10 mW / cm². 2 .
[0049] Step 5: The hydrogel is subjected to freeze-thaw cycle treatment: freeze for 20 hours, thaw for 4 hours, and repeat the freeze-thaw treatment three times to obtain the hydrogel dressing.
[0050] The three groups of hydrogels were named PPM according to their MXene concentrations. 100 PPM 200 and PPM 400 And then conduct subsequent experimental tests.
[0051] Experimental results 1. Mechanical properties All types of hydrogels can be compressed to 60% deformation without breaking. Figure 2 (a) demonstrates good compression resistance and can withstand the slight compression that may occur in clinical applications. Further quantitative analysis shows that PPM 100 PPM 200 and PPM 400 The compressive moduli of the hydrogels were 34.92 kPa, 41.29 kPa, and 40.77 kPa, respectively. Figure 2 In b, where * and ns represent significance markers (PPM). 400 The compression cycle curve of the hydrogel is as follows Figure 2 As shown in Figure c, in thirty compression cycles, the compression amount was 30% of its original height each time. After the load was removed, the hydrogel could completely recover its initial height, demonstrating good mechanical properties.
[0052] PPM 100 PPM 200 and PPM 400 The tensile stress-strain curve of the hydrogel is as follows: Figure 2 As shown in d, PPM can be calculated through curve fitting. 100 and PPM 400 The Young's modulus of the hydrogels reached 17.134 kPa and 17.418 kPa, respectively, in PPM. 200 The hydrogel has a pressure of approximately 13.156 kPa. Figure 2 In the text, e represents the significance marker (where * and ns represent significance markers). PPM 400 The stretching cycle curve of the hydrogel is as follows Figure 2As shown in Figure f, after 30 cycles of tensile testing, the stress-strain curve of the hydrogel showed almost no significant shift, indicating that it possesses excellent tensile fatigue resistance and structural stability.
[0053] Hydrogels exhibit sufficient adhesion to various substrates through hydrogen bonding and electrostatic interactions. For example... Figure 2 As shown in g, PPM 400 Hydrogels can adhere firmly to various materials (such as plastics and steel), exhibiting strong adhesion. Subsequently, PPM... 400 When the hydrogel is applied to the finger joints, volunteers can bend their fingers freely without any resistance. During this process, the hydrogel maintains good adhesion and does not shift or break.
[0054] 2. Biocompatibility This invention analyzes the biocompatibility of hydrogel dressings from two aspects: blood compatibility and cell compatibility. Good biocompatibility is an important prerequisite for hydrogels to promote wound healing. The control group consisted of normally cultured cells without any treatment. Figure 3 As can be seen from the CCK-8 results, L929 fibroblasts exhibited significant cell proliferation within 1-5 days regarding cell compatibility. In the live / dead staining results, large green fluorescent spots (live cells) were visible in all groups on day 5. Hemolysis results showed that PPM... 100 PPM 200 PPM 400 The hemolysis rate of the hydrogel dressings was lower than the standard hemolysis rate (4%) of the material, indicating that PPM 400 The hydrogel exhibits good blood compatibility. Rabbit blood treated with deionized water and PBS served as positive and negative controls, respectively, while Negative and Positive values corresponded to the OD values of the negative and positive control groups, respectively.
[0055] 3. Antibacterial properties Hydrogels with highly effective antibacterial properties can actively intervene in wound infection, significantly improving their clinical applicability in wound management. We divided the experimental samples into a control group and PPM. 400 The antibacterial properties of the bacteria against *Escherichia coli* (Gram-negative bacteria) and *Staphylococcus aureus* (Gram-positive bacteria) were evaluated in groups. Figure 4 As shown in Figure a, PPM 400 It exhibited a significant antibacterial effect. Subsequently, PPM... 400 Quantitative evaluation of the antibacterial ability of hydrogels ( Figure 4 In the middle b, where * and ns represent significance markers, the results show PPM 400 The inhibition rates against Staphylococcus aureus and Escherichia coli reached 77.5% and 83.4%, respectively.
[0056] 4. Conductivity sensing performance Mxene, as a two-dimensional layered nanomaterial, contains a large number of freely moving charge carriers, which can construct continuous conductive pathways in hydrogel systems, thereby effectively improving the conductivity of hydrogels. For example... Figure 5 As shown in Figure a, the composite hydrogel containing only polyvinyl alcohol and poly(N-isopropylacrylamide) has a very low conductivity, approximately 0.009 S / cm, which is almost negligible, while the PPM containing Mxene... 400 The conductivity of the hydrogel is 0.029 S / cm, which is approximately 3.2 times different from that of the other gel. (PPM) 400 Hydrogel sensors need to maintain high sensitivity over a wide operating strain range to accommodate the irregularities in the amplitude and frequency of human movement. The strain coefficient (GF) is calculated based on the slope of the relative resistance change curve during stretching. Figure 5 In b, we found PPM 400 The relative resistivity of the conductive hydrogel increases with increasing tensile strain, and the curve is divided into two linear response regions: 0-35% when GF is 0.49 and 35-40% when GF is 2.92. (PPM) 400 The hydrogel exhibited good repeatability in sensing properties from 0% strain to 15% strain. Figure 5 (c)
[0057] Thanks to PPM 400 The high sensitivity of hydrogels allows the sensor to detect different signals when a patient's finger is bent at different angles, showing great potential in information transmission. Figure 5 (d) When the patient's wrist is bent at different speeds, it can be measured from PPM. 400 The real-time signal from the hydrogel sensor clearly distinguishes different frequencies, further demonstrating the effectiveness of PPM. 400 Sensitivity of hydrogel sensors ( Figure 5 (e). Characteristic movement signals from other parts of the body can also be detected through PPM. 400 Hydrogel sensors detect, for example, elbow flexion ( Figure 5 (f)
[0058] 5. Shrinkage rate in different regions Figure 6 The shrinkage rate of different regions of hydrogels with different shapes designed at 37℃ was measured. It can be seen that the shrinkage rate varies significantly across different regions; the sparser the mesh, the greater the shrinkage rate. This also proves the effectiveness of PPM. 400 Feasibility of hydrogel localized and point-based shrinkage.
[0059] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing a multifunctional hydrogel dressing with targeted shrinkage, characterized in that, include: Step 1: Mix phosphate buffer solution with polyvinyl alcohol and heat to obtain polyvinyl alcohol solution; Step 2: Under light-protected conditions, mix phosphate buffer solution, N-isopropylacrylamide, N,N'-methylenebisacrylamide, and phenyl (2,4,6-trimethylbenzoyl) lithium phosphate to obtain a mixture; Step 3: Mix the polyvinyl alcohol solution with the mixed liquid, add MXene dispersion, and sonicate to obtain a composite solution; Step 4: After setting the printing and lighting parameters, follow the preset pattern path, use the composite solution as the printing ink, and obtain the hydrogel by photopolymerization 3D printing. Step 5: The hydrogel is subjected to freeze-thaw cycles to obtain a hydrogel dressing.
2. The method for preparing the multifunctional hydrogel dressing with positionable and localized shrinkage according to claim 1, characterized in that, In the composite solution of step 3, the mass ratio of polyvinyl alcohol to N-isopropylacrylamide is 0.8-1.2:1, the mass ratio of N-isopropylacrylamide to N,N'-methylenebisacrylamide is 1:0.025-0.035, and the mass ratio of N-isopropylacrylamide to phenyl(2,4,6-trimethylbenzoyl)lithium phosphate is 1:0.025-0.
035.
3. The method for preparing the multifunctional hydrogel dressing with positionable and localized shrinkage according to claim 1, characterized in that, The mass ratio of MXene material to N-isopropylacrylamide is 1:250-1:1000.
4. The method for preparing the multifunctional hydrogel dressing with positionable and localized shrinkage according to claim 1, characterized in that, Step 4 is performed as follows: Step 41: Create a 3D model based on the shape of the wound, dividing it into loose area, dense area and transition area; Step 42: Set the spacing between the print lines in each zone and generate the print path; Step 43: Using the composite solution as printing ink, print layer by layer according to the printing path, and cure the shape by ultraviolet light.
5. The method for preparing the multifunctional hydrogel dressing with positionable and localized shrinkage according to claim 4, characterized in that, Step 42 generates the print path, including: Step a: Under fixed lighting parameters, print test lines with different designed line widths, measure the actual line width, establish the first mapping model between the designed line width and the actual line width, and at the same time establish the second mapping model between the actual line width and the shrinkage rate; Step b: After determining the target shrinkage rates of the loose zone, dense zone, and transition zone, determine the target actual linewidth based on the target shrinkage rate and the second mapping model; determine the target design linewidth based on the target actual linewidth and the first mapping model. Step c: Generate the printing path for each area based on the target line width and line spacing.
6. The method for preparing the multifunctional hydrogel dressing with positionable and localized shrinkage according to claim 5, characterized in that, The illumination time for each layer is 10 seconds, and the illumination intensity is 10 mW / cm². 2 .
7. The method for preparing the multifunctional hydrogel dressing with positionable and localized shrinkage according to claim 4, characterized in that, The line spacing mentioned in step 42 is determined based on the target shrinkage rate of each zone.
8. The method for preparing the multifunctional hydrogel dressing with positionable and localized shrinkage according to claim 7, characterized in that, The line spacing in the loose area is 1.0-1.5mm, and the line spacing in the dense area is 0.2-0.5mm.
9. The method for preparing the multifunctional hydrogel dressing with positionable and localized shrinkage according to claim 8, characterized in that, The line spacing in the transition zone is 0.5-1.0mm.
10. The method for preparing the multifunctional hydrogel dressing with positionable and localized shrinkage according to claim 1, characterized in that, In step 4, the preset patterns include grid-like, radial, concentric circle, parallel line, or biomimetic fractal structures.