A programmed drug release composite structure functional dressing and a preparation method thereof

Abstract

The present application belongs to the technical field of biological materials, and relates to a programmed drug release composite structure functional dressing and a preparation method thereof. The dressing is composed of an antibacterial and anti-inflammatory hydrogel and a 3D printed hydrogel fiber network completely embedded in the antibacterial and anti-inflammatory hydrogel; the 3D printed hydrogel fiber network is made of 3D printing ink; the 3D printing ink comprises a hydrogel base material, hyaluronic acid, a photoinitiator and water, and the hydrogel base material is a photocrosslinking polymer. The preparation method comprises the following steps: first, 1 / 2-2 / 3 of the total volume of antibacterial and anti-inflammatory hydrogel precursor solution is added to a mold, then the mold is placed under specific conditions for a period of time, then the 3D printed hydrogel fiber network is placed in the center of the antibacterial and anti-inflammatory hydrogel precursor solution, finally, the remaining antibacterial and anti-inflammatory hydrogel precursor solution is added, and the antibacterial and anti-inflammatory hydrogel precursor solution is crosslinked to obtain the dressing. The dressing can precisely match the requirements of each stage of wound healing, and has the functions of programmed drug release and physical and biological stimulation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biological materials, and relates to a programmed drug release composite structure functional dressing and a preparation method thereof. BACKGROUND

[0002] After skin injury, scar formation not only causes abnormal appearance, but also causes the skin to lose normal physiological functions such as temperature regulation and barrier protection, bringing significant health risks and psychological burdens to patients. In skin injury repair, functional dressing is a core intervention material, which can not only replace the temporary structural support of damaged skin to provide physical space for cell migration and proliferation, but also regulate the wound healing microenvironment by loading active ingredients (such as antibacterial agents and growth factors) to reduce scar formation from the source.

[0003] Wound healing is a dynamic and progressive complex process, and the functional requirements of dressing are significantly different at different stages: in the inflammatory stage, excessive inflammation is easily caused by bacterial invasion, and dressing needs to quickly release antibacterial agents to inhibit infection and regulate the immune microenvironment; the proliferation stage is the key to scar prevention and control, and dressing needs to accurately release growth factors to promote vascular regeneration, while regulating TGF-β / Smad and other signaling pathways to inhibit the excessive activation of fibroblasts. This means that functional dressing needs to have a time-sequential drug release performance to achieve the precise matching of "antibacterial agent burst release in the inflammatory stage and growth factor sustained release in the proliferation stage".

[0004] Patent application CN112587709A discloses a 3D printed dressing tape containing multiple growth factors and a preparation method. The method uses a combination of complex wrapping and hydrogel matrix technology to solve the problem of drug burst release, can release growth factors at key nodes of wound healing, and thus make high-end dressings that can promote wound healing and reduce scar formation, and make the release of growth factors and the wound healing period synchronous. However, since multiple active ingredients are wrapped in the same microspheres, the release rates of these active ingredients are consistent, and the time-sequential matching of "fast burst release of antibacterial agents in the inflammatory stage" and "slow sustained release of growth factors in the proliferation stage" cannot be achieved, making it difficult to meet the stage-by-stage needs of wound healing.

[0005] Patent application CN112569399A discloses a photo-crosslinking / electrospinning preparation and application of a double-layer skin structure hydrogel composite scaffold, which is prepared by electrospinning and patterned photo-crosslinking hydrogel to obtain a functional scaffold with a biomimetic structure. The electrospun fiber membrane simulates the epidermis layer, which can block the invasion of foreign bodies and pathogens and prevent the loss of interstitial fluid; the patterned cylindrical hydrogel can support cell growth and adhesion, promote migration and proliferation, and help skin tissue regeneration. However, only the physical structure of different materials is used to provide stimulation to the wound, and there is a lack of adaptation ability to the stage-by-stage needs of wound healing, making it difficult to intervene in the scar formation process from the biological activity level.

[0006] Therefore, it is of great significance to design a multifunctional dressing capable of precisely matching the needs of each stage of wound healing, having programmed drug release and physical and biological stimulation functions, to improve the scar inhibition effect and promote functional regeneration of the skin. SUMMARY

[0007] The purpose of the present application is to solve the problems existing in the prior art and provide a programmed drug release composite structure functional dressing and a preparation method thereof.

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

[0009] A programmed drug release composite structure functional dressing, which is composed of an antibacterial and anti-inflammatory hydrogel and a 3D printed hydrogel fiber network completely embedded in the antibacterial and anti-inflammatory hydrogel.

[0010] The preparation process of the 3D printed hydrogel fiber network is as follows: using an extrusion type 3D printer, 3D printing ink is extruded and printed according to a computer preset grid pattern (fiber spacing is 500-1000 μm, and the number of printing layers is 4-6 layers), and ultraviolet light is used for irradiation during the extrusion process, thereby obtaining the 3D printed hydrogel fiber network; wherein the printing temperature is 26-40℃.

[0011] The 3D printing ink comprises a hydrogel base material, hyaluronic acid, a photoinitiator and water, the hydrogel base material is a photocrosslinking polymer, the mass ratio of the photocrosslinking polymer to the hyaluronic acid is 5-15:2.5-3, and the weight average molecular weight of the hyaluronic acid is 1.5-2.5 million g / mol.

[0012] When the preset grid pattern is a square, the printable value Pr of the shape of the 3D printed hydrogel fiber network is 0.95-1.05, the printable value Pr of the square is 1, and the closer the printable value Pr of the shape of the 3D printed hydrogel fiber network is to 1, the closer the shape of the 3D printed hydrogel fiber network is to a square, indicating that the accuracy of the printed structure is higher; the high-precision fiber network can form a through-hole structure to provide physical space for cell growth and migration, solving the problem of large batch difference and inability to manufacture fine macroscopic structures by ordinary extrusion printing.

[0013] The degradation time of the antibacterial and anti-inflammatory hydrogel is 3-7 days, and the degradation time of the 3D printed hydrogel fiber network is 21-45 days, and the degradation time is closely related to the crosslinking density, which can be adjusted to control the degradation time.

[0014] The combination of photocrosslinkable polymer and hyaluronic acid, its chemical nature (photo-crosslinkable) and physical form (polymer solution) must determine its non-Newtonian fluid behavior and printing characteristics. The numerical range of viscosity and elastic modulus is the inherent property of the material system at a reasonable concentration. The high molecular chain (especially hyaluronic acid) forms a weak and reversible physical crosslinking network through physical entanglement and hydrogen bonding, which gives the ink "pre-gel" solid state behavior and elasticity. When high shear force is applied, these weak physical crosslinks are broken, and the high molecular chain is oriented along the flow direction, resulting in a decrease in viscosity and elastic modulus, and becomes easy to flow. Once the shear force is removed, the physical entanglement and hydrogen bonding are instantly rebuilt (reversible physical process), and the viscosity and elastic modulus quickly recover, thereby supporting the printed structure and preventing collapse.

[0015] Hyaluronic acid provides excellent shear thinning and elasticity due to its long chain and rigid molecular structure. When the addition amount of hyaluronic acid relative to the photocrosslinkable polymer is too low, the physical entanglement network is insufficient, resulting in low viscosity and elastic modulus of the solution, and the ink exhibits a solution state, which cannot maintain a filamentous form; similarly, when the addition amount of hyaluronic acid relative to the photocrosslinkable polymer is too high, the viscosity and elastic modulus of the solution are too high, resulting in high extrusion pressure or even inability to extrude. The molecular weight of hyaluronic acid directly determines the length of the molecular chain, thereby affecting the strength and density of physical entanglement; if the molecular weight is too small, the molecular chain is too short, and cannot effectively entangle to form a strong physical network, the shear thinning effect is weak, and the elastic recovery is poor; if the molecular weight is too large, the molecular chain is too long, and the entanglement is too dense, resulting in a very high zero-shear viscosity, and even if under high shear, the viscosity may not decrease to a suitable range for extrusion, at the same time, its elastic recovery is extremely fast, which may start to rebound inside the nozzle or at the outlet, increasing the extrusion resistance, and even causing the nozzle to be blocked.

[0016] The present application controls the mass ratio of photocrosslinkable polymer and hyaluronic acid, and the weight average molecular weight of hyaluronic acid, so as to form a physical entanglement molecular chain interpenetrating network, which is not significantly affected by external temperature environment, and gives the ink excellent shear thinning and instantaneous elastic recovery capability, solving the poor printing performance of existing ink from the material itself.

[0017] The present application effectively solves the temperature sensitivity limitation of the interpenetrating network formed by hyaluronic acid and methacrylated gelatin, expands the printing temperature window, reduces the printing condition requirements, and improves the operability and repeatability of printing. The present application uses the rapid curing mechanism of ultraviolet irradiation during extrusion, and the ink can be precisely chemically crosslinked in a few seconds, converting from "gel state" to "solid state", which is triggered by external factors, avoiding the slow and uncontrollable nature of physical crosslinking and ionic crosslinking, further ensuring the accuracy of the printed structure.

[0018] The antibacterial and anti-inflammatory hydrogel rapidly degrades in the inflammatory stage of the wound, and the antibacterial agent plays an antibacterial and anti-inflammatory role to regulate the immune microenvironment of the wound. The 3D printed hydrogel fiber network is exposed in the wound area after the antibacterial and anti-inflammatory hydrogel degrades, and the growth factors loaded therein synergistically promote the vascular formation behavior of endothelial cells and simultaneously inhibit the TGF-β / Smad signal pathway of fibroblasts, so as to dynamically regulate the cell behavior in space and time and promote skin tissue regeneration.

[0019] The present application controls the degradation rate by the composite structure design and the cross-linking density regulation (the higher the content of the photo-crosslinking polymer, the slower the degradation), so that the outer antibacterial and anti-inflammatory hydrogel (low concentration of photo-crosslinking polymer) rapidly degrades to realize the burst release of the antibacterial agent, and the inner fiber network (high concentration of photo-crosslinking polymer) slowly degrades to realize the sustained release of the drug (such as growth factor), and no external stimulus is needed to actively realize the precise time sequence control; at the same time, the three-dimensional fiber network structure avoids the limitation of two-dimensional materials, and the water system preparation has no organic solvent residue.

[0020] As a preferred technical solution:

[0021] The content of the photo-crosslinking polymer in the 3D printing ink is 10-20wt%, and the content of the photoinitiator is 0.1-0.5wt%.

[0022] The 3D printing ink also comprises 10-50μg / mL of growth factor (such as basic fibroblast growth factor, which can promote angiogenesis on the one hand and inhibit the TGF-β / Smad signal pathway on the other hand).

[0023] The preparation process of the 3D printing ink is as follows: the photo-crosslinking polymer, hyaluronic acid, photoinitiator and growth factor are added into a phosphate buffered saline solution, and stirred for 120-240min to obtain the 3D printing ink.

[0024] The 3D printing ink of the present application does not contain any organic solvent and toxic ingredients, can maintain the whole activity of the active substances such as growth factors, has excellent biocompatibility, and avoids the problems of inactivation and residual toxicity of active ingredients caused by the dependence of polymer processing on organic solvents in the prior art.

[0025] The photo-crosslinking polymer is methacrylated gelatin (GelMA).

[0026] The functionalized drug release composite structure dressing as described above, when no shear force is applied, the 3D printing ink has a viscosity of 10-50 Pa·s and an elastic modulus of 1-10 Pa; when a shear force of 10-50 Pa (close to the shear force in the extrusion printing process) is applied, the 3D printing ink has a viscosity of 0.1-10 Pa·s and an elastic modulus of 0.001-0.01 Pa.

[0027] The functionalized drug release composite structure dressing as described above, the peeling strength of the antibacterial and anti-inflammatory hydrogel and the 3D printing hydrogel fiber network is 10-100 cN, so the two are firmly combined and are not easy to separate.

[0028] In the present application, the antibacterial and anti-inflammatory hydrogel and the 3D printing hydrogel fiber network are not simply physically wrapped, but are strongly combined through a specific preparation process, avoiding the problem of weak interface combination and easy separation of existing composite dressings, and ensuring stable function of the dressing in the whole cycle of wound healing.

[0029] The present application also provides a method for preparing the functionalized drug release composite structure dressing as described in any one of the above, first adding 1 / 2-2 / 3 of the total volume of the antibacterial and anti-inflammatory hydrogel precursor solution in the mold, then standing at -20℃ for 10-30 min (the purpose is to make the antibacterial and anti-inflammatory hydrogel precursor solution into a gel state, so as to ensure that the subsequent 3D printing hydrogel fiber network can float above), then placing the 3D printing hydrogel fiber network in the center of the antibacterial and anti-inflammatory hydrogel precursor solution, finally adding the remaining antibacterial and anti-inflammatory hydrogel precursor solution, and initiating crosslinking of the antibacterial and anti-inflammatory hydrogel precursor solution, to obtain the functionalized drug release composite structure dressing.

[0030] The dressing preparation method of the present application is simple, the fiber network can be accurately wrapped inside the antibacterial and anti-inflammatory hydrogel by using physical embedding method, and is highly operable, compatible with existing processes, and does not require complex equipment, solving the problem of complicated preparation process and high equipment dependence of existing high-end dressings.

[0031] As a preferred technical solution:

[0032] The method as described above, the antibacterial and anti-inflammatory hydrogel precursor solution comprises 1-5 wt% of a photocrosslinking polymer (methylacrylated gelatin, methylacrylated hyaluronic acid, methylacrylated chitosan or methylacrylated sodium alginate), 0.1-0.5 wt% of a photoinitiator (one of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone and phenyl(2,4,6-trimethylbenzoyl) lithium phosphate), 0.05-0.1 wt% of an antibacterial agent (genipin), and water;

[0033] The preparation process of the antibacterial and anti-inflammatory hydrogel precursor solution is as follows: the photocrosslinking polymer, the photoinitiator and the antibacterial agent are added into the phosphate buffered saline solution, and stirring is performed for 120-240 min, so as to obtain the antibacterial and anti-inflammatory hydrogel precursor solution.

[0034] The crosslinking of the antibacterial and anti-inflammatory hydrogel precursor solution is initiated by irradiating with ultraviolet light for 3-20 min.

[0035] By controlling the concentration (1-5 wt%) of the photocrosslinking polymer, the degradation rate of the antibacterial and anti-inflammatory hydrogel can be accurately controlled, so as to ensure that the antibacterial and anti-inflammatory hydrogel is quickly degraded and releases the antibacterial agent during the inflammation period, and at the same time, to provide initial protection for the inner fiber network, and to realize the functional synergy of "outer layer protection-inner layer effect".

[0036] Advantages:

[0037] (1) The antibacterial and anti-inflammatory hydrogel and the 3D printed hydrogel fiber network are combined to form a composite structure, and the programmed drug release is realized by using the degradation time difference between the two. The antibacterial and anti-inflammatory hydrogel releases the antibacterial agent to regulate the immune microenvironment during the inflammation period, and the 3D printed hydrogel fiber network releases the growth factor to regulate the cell behavior during the proliferation period, thereby solving the problem that the active ingredient release rate is consistent in the prior art and cannot adapt to the phased needs of wound healing.

[0038] (2) The present application realizes the synergistic effect of physical stimulation and biological stimulation. The through-hole structure of the 3D printed hydrogel fiber network provides physical support and cell growth space, and the growth factor loaded therein can inhibit related signal pathways and promote blood vessel formation, thereby solving the problem that the prior art only relies on physical structure stimulation and lacks biological activity intervention for scar formation.

[0039] (3) The present application optimizes the component ratio (complex of photocrosslinking polymer and specific molecular weight hyaluronic acid) of the 3D printing ink, gives the ink excellent printing properties, and combines the extrusion printing and synchronous ultraviolet crosslinking process, so as to prepare the 3D printed hydrogel fiber network with accurate shape, thereby providing a reliable structural basis for realizing the function of the dressing.

[0040] (4) The present application uses a specific composite preparation process to firmly combine the antibacterial and anti-inflammatory hydrogel with the 3D printed hydrogel fiber network, so as to avoid separation during use and ensure that the dressing functions stably during the whole wound healing cycle. DETAILED DESCRIPTION

[0041] Figure 1 The photomicrograph of the 3D printed hydrogel fiber network of Example 4 of the present application; wherein (a) is a single-layer grid structure, and (b) is a double-layer grid structure.

[0042] Figure 2Photomicrograph of the degradation behavior of the programmed drug release composite structure functional dressing of Example 1 (wherein the white dotted line is the outer contour line of the sample);

[0043] Figure 3 Cumulative drug release rate-time curve of the 3D printed hydrogel fiber network containing bovine serum albumin in Example 1 and the programmed drug release composite structure functional dressing. DETAILED DESCRIPTION

[0044] The application will be further described in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the application and not used to limit the scope of the application. Furthermore, it should be understood that after reading the content taught by the application, those skilled in the art can make various modifications or changes to the application, and these equivalent forms also fall within the scope defined by the appended claims of the application.

[0045] In order to fully disclose the properties of the substances used in each example and comparative example, the manufacturer information of the substances is written in the application. In addition, the products of other manufacturers that meet the definition of the application are also applicable.

[0046] The following is the test method of the relevant performance indicators in each example and comparative example:

[0047] Viscosity: rheological test of the sample was performed using a rotational rheometer (MCR302, Anton Paar, Austria), the sample was dropped into the tray of the rheometer, a 25mm flat plate was used for testing, the test temperature was 40℃, the "viscosity curve" test module was selected, the test interval was set to 1mm, the constant strain was 1%, and the shear rate was 0.01-100s⁻¹;

[0048] Elastic modulus: rheological test of the sample was performed using a rotational rheometer (MCR302, Anton Paar, Austria), the sample was dropped into the tray of the rheometer, a 25mm flat plate was used for testing, the test temperature was 40℃, the "oscillation mode" - "frequency sweep" test module was selected, the test interval was set to 1mm, the constant strain was 1%, and the frequency was 0.01-100Hz;

[0049] Printable value Pr: the formula for calculating the circularity of a square is C=4πA / L² (the circularity value of a square is π / 4), the formula for printing is Pr=(π / 4) / C=L² / (16A); the printed figure was analyzed and calculated using ImageJ software, wherein A is the area of the closed figure, and L is the perimeter of the closed figure;

[0050] Degradation time: the same weight and volume of samples were freeze-dried and placed in a 12-well plate for ultraviolet sterilization, 3 mL of sterile PBS buffer (pH = 5.5 or pH = 7.4) was added to each well, and degradation was carried out at 37°C in a shaking incubator at 60 rpm, the PBS buffer was replaced every two days until the sample completely disintegrated, and the required time was recorded as the degradation time;

[0051] Peeling strength: a microcomputer-controlled electronic universal testing machine (CTM2050) was used for testing, the sample was clamped with upper and lower clamps, the distance between the upper and lower clamps was adjusted to 20 mm, and then peeling was carried out at a constant stretching speed (50 mm / min) until the middle 3D printed hydrogel fiber network was exposed, and the maximum tensile strength was taken as the peeling strength.

[0052] In the following examples, the synthesis steps of methacrylated gelatin are as follows:

[0053] (1) Under the condition of 50°C water bath heating, a 10% gelatin aqueous solution (the manufacturer of gelatin is Sigma-Aldrich, and the product number is G2500) was prepared;

[0054] (2) According to the mass ratio of gelatin to methacrylic anhydride 1:0.6, methacrylic anhydride was added to the gelatin aqueous solution at a rate of 0.5 mL / min, and the reaction was carried out for 4h;

[0055] (3) After the reaction was completed, the system was centrifuged for 3 min, and the supernatant was taken and diluted with 2-4 times the volume of ultrapure water;

[0056] (4) The product of step (3) was loaded into a dialysis bag (MD44) with a molecular weight cut-off of 12-14 kDa, and dialyzed in ultrapure water at 40°C for 7 days, and the ultrapure water was replaced at least once a day during the period;

[0057] (5) The pH value of the product of step (4) was adjusted to 7.4 with 1M sodium bicarbonate aqueous solution;

[0058] (6) The product of step (5) was placed in a -80°C refrigerator overnight (or frozen in a liquid nitrogen tank for 2h), and then transferred to a freeze dryer for freeze drying for 5 days, to obtain methacrylated gelatin.

[0059] In the following examples, the synthesis steps of methacrylated hyaluronic acid are as follows:

[0060] (1) A 1% hyaluronic acid aqueous solution (the manufacturer of hyaluronic acid is Shanghai Maikelin Biochemical Technology Co., Ltd., and the product number is H909936) was prepared under stirring at room temperature;

[0061] (2) The methacrylic anhydride is added to the hyaluronic acid aqueous solution at a rate of 0.5 mL / min according to a mass ratio of 3:1 between the methacrylic anhydride and the hyaluronic acid, and the dropping process is accompanied by continuous stirring, and the reaction is performed for 8 h;

[0062] (3) After the reaction is completed, the pH value of the system is adjusted to 8.5 by using a 5M NaOH aqueous solution;

[0063] (4) The product of step (3) is loaded into a dialysis bag (MD44) with a molecular weight cut-off of 12-14 kDa, and dialysis is performed in ultrapure water for 7 days, during which the ultrapure water is replaced at least once a day;

[0064] (5) The product of step (4) is placed in a -80℃ refrigerator overnight (or frozen in a liquid nitrogen tank for 2 h), and then transferred to a freeze dryer for freeze drying for 5 days, thereby obtaining the methacrylated hyaluronic acid.

[0065] In the following examples, the synthesis steps of the methacrylated chitosan are as follows:

[0066] (1) A chitosan solution with a mass fraction of 3% is prepared by stirring with a 1% acetic acid aqueous solution (the chitosan is from Shanghai Aladdin Bio-Chem Technology Co., Ltd., and the product number is C105799);

[0067] (2) The methacrylic anhydride is added to the chitosan solution according to a mass ratio of 3.5:1 between the methacrylic anhydride and the chitosan, and the reaction is continuously stirred at room temperature for 3 h;

[0068] (3) After the reaction is completed, the reaction solution is diluted with 2-4 times the volume of ultrapure water, and then the diluted solution is loaded into a dialysis bag (MD44) with a molecular weight cut-off of 12-14 kDa, and dialysis is performed in ultrapure water for 7 days, during which the ultrapure water is replaced at least once a day;

[0069] (4) The product of step (3) is frozen in a -80℃ refrigerator overnight (or quickly frozen in a liquid nitrogen tank for 2 h), and then transferred to a freeze dryer for freeze drying for 5 days, thereby obtaining the methacrylated chitosan.

[0070] In the following examples, the synthesis steps of the methacrylated sodium alginate are as follows:

[0071] (1) Under the condition of heating at 50℃ in a water bath, a 1% sodium alginate aqueous solution is prepared by stirring (the sodium alginate is from Shanghai Haohong Biomedical Technology Co., Ltd., and the product number is 1087623), and then the pH value of the system is adjusted to 8.0 by using a 5M NaOH aqueous solution, and then the solution is cooled to 4℃ by using a cold water bath, and the low-temperature stirring state is maintained;

[0072] (2) The methacrylic anhydride was added to the low-temperature sodium alginate solution at a rate of 0.5 mL / min for 5 h, and the system temperature was maintained at 0-5°C and the pH value was maintained at 8-9 during the reaction (the temperature was controlled by a cold water bath, and the pH value was adjusted by adding 5M NaOH solution);

[0073] (3) After the reaction was completed, the cold water bath was removed, and the reaction solution was stirred at room temperature for 12 h, then the reaction solution was loaded into a dialysis bag with a molecular weight cut-off of 12-14 kDa (MD44), and dialyzed in ultrapure water for 7 days, and the ultrapure water was replaced at least once a day;

[0074] (4) The product of step (3) was frozen overnight in a -80°C refrigerator (or quickly frozen in a liquid nitrogen tank for 2 h), and then transferred to a freeze dryer for freeze-drying for 5 days to obtain the methacrylated sodium alginate.

[0075] In each of the following examples and comparative examples, the wavelength of the ultraviolet light was 365 nm.

[0076] Example 1

[0077] A method for preparing a programmed drug release composite functional dressing, the specific steps are as follows:

[0078] (1) Preparation of raw materials;

[0079] Photocrosslinking polymer a: methacrylated gelatin;

[0080] Hyaluronic acid: weight average molecular weight of 1.5 million g / mol;

[0081] Photoinitiator a, photoinitiator b: both are lithium phenyl (2,4,6-trimethylbenzoyl) phosphate;

[0082] Growth factor: basic fibroblast growth factor, CAS number 106096-93-9;

[0083] Phosphate buffered saline solution: manufacturer Beijing Wakai Biological Technology Co., Ltd., product number A55535;

[0084] Photocrosslinking polymer b: methacrylated gelatin;

[0085] Antibacterial agent: genipin;

[0086] (2) Preparation of 3D printing ink;

[0087] The photocrosslinking polymer a, hyaluronic acid, photoinitiator a, and growth factor were added to the phosphate buffered saline solution and stirred for 180 min to obtain the 3D printing ink;

[0088] In the 3D printing ink, the mass ratio of the photocrosslinking polymer a to the hyaluronic acid is 10:2.75, the content of the photocrosslinking polymer a is 10 wt%, the content of the photoinitiator a is 0.1 wt%, and the content of the growth factor is 20 μg / mL; when no shear force is applied, the viscosity of the 3D printing ink is 20 Pa·s, and the elastic modulus is 3 Pa; when a shear force of 50 Pa is applied, the viscosity of the 3D printing ink is 1.5 Pa·s, and the elastic modulus is 0.003 Pa;

[0089] (3) preparing a 3D printing hydrogel fiber network and an antibacterial and anti-inflammatory hydrogel precursor solution;

[0090] The preparation process of the 3D printing hydrogel fiber network is as follows: using an extrusion type 3D printer, the 3D printing ink is extruded and printed according to a computer preset grid pattern (fiber distance is 800 μm, and the printing layer number is 4 layers) (the printing temperature is 40 ℃), and ultraviolet light is used for irradiation during the extrusion process, so that the 3D printing hydrogel fiber network is obtained;

[0091] When the preset grid pattern is a square, the printable numerical value Pr of the shape of the 3D printing hydrogel fiber network is 1.01;

[0092] The preparation process of the antibacterial and anti-inflammatory hydrogel precursor solution is as follows: the photocrosslinking polymer b, the photoinitiator b and the antibacterial agent are added into the phosphate buffered saline solution, and stirred for 120 min, so that the antibacterial and anti-inflammatory hydrogel precursor solution is obtained;

[0093] In the antibacterial and anti-inflammatory hydrogel precursor solution, the content of the photocrosslinking polymer b is 5 wt%, the content of the photoinitiator b is 0.1 wt%, and the content of the antibacterial agent is 0.08 wt%.

[0094] (4) preparing a programmed drug release composite structure functional dressing;

[0095] Firstly, the antibacterial and anti-inflammatory hydrogel precursor solution accounts for 1 / 2 of the total volume is added into the mold, then the mold is placed at -20 ℃ for 10 min, then the 3D printing hydrogel fiber network is placed in the center of the antibacterial and anti-inflammatory hydrogel precursor solution, finally, the remaining antibacterial and anti-inflammatory hydrogel precursor solution is added, and then ultraviolet light is irradiated for 3 min, so that the programmed drug release composite structure functional dressing is obtained.

[0096] The finally prepared programmed drug release composite structure functional dressing is composed of the antibacterial and anti-inflammatory hydrogel and the 3D printing hydrogel fiber network completely embedded in the antibacterial and anti-inflammatory hydrogel, the degradation time of the antibacterial and anti-inflammatory hydrogel is 3 days, the degradation time of the 3D printing hydrogel fiber network is 21 days, and the degradation behavior of the programmed drug release composite structure functional dressing is as shown in Figure 2 The peeling strength of the antibacterial and anti-inflammatory hydrogel and the 3D printing hydrogel fiber network is 20 cN.

[0097] To test the release of basic fibroblast growth factor in different samples, bovine serum albumin (CAS No. 9048-46-8) was used for release experiments, and bovine serum albumin was added to the 3D printing ink (preparation process same as this embodiment) at a concentration of 100 μg / mL; the 3D printing ink added with bovine serum albumin was divided into two groups: one group was prepared into a programmed drug release composite structure functional dressing containing bovine serum albumin according to the steps of this embodiment, and the other group was prepared into a 3D printing hydrogel fiber network containing bovine serum albumin according to the steps of this embodiment, and the two groups of samples were respectively placed in a 12-well plate, 2 mL of phosphate buffered saline solution (manufacturer: Beijing Wakai Biological Technology Co., Ltd., product number: A55535) was added to each well, and then detected according to the method of BCA kit (Feijing Scientific Reagent, product number: PH0326) instruction manual, calculated according to the formula Figure 3 The drug release curve is shown in

[0098] Example 2

[0099] A method for preparing a programmed drug release composite structure functional dressing, the specific steps are as follows:

[0100] (1) Preparation of raw materials;

[0101] Photocrosslinkable polymer a: methacrylated gelatin;

[0102] Hyaluronic acid: weight average molecular weight of 1.8 million g / mol;

[0103] Photoinitiator a, photoinitiator b: both are 2-hydroxy-4'-(2-hydroxyethoxy)-2-methyl propiophenone;

[0104] Growth factor: basic fibroblast growth factor, CAS No. 106096-93-9;

[0105] Phosphate buffered saline solution: manufacturer: Beijing Wakai Biological Technology Co., Ltd., product number: A55535;

[0106] Photocrosslinkable polymer b: methacrylated gelatin;

[0107] Antibacterial agent: genipin;

[0108] (2) Preparation of 3D printing ink;

[0109] Add photocrosslinkable polymer a, hyaluronic acid, photoinitiator a, and growth factor into the phosphate buffered saline solution and stir for 240 min to obtain the 3D printing ink;

[0110] ​In the 3D printing ink, the mass ratio of the photocrosslinking polymer a to the hyaluronic acid is 10:3, the content of the photocrosslinking polymer a is 15wt%, the content of the photoinitiator a is 0.1wt%, and the content of the growth factor is 20μg / mL; when no shear force is applied, the viscosity of the 3D printing ink is 30Pa·s, and the elastic modulus is 1.5Pa; when a shear force of 40Pa is applied, the viscosity of the 3D printing ink is 5Pa·s, and the elastic modulus is 0.005Pa;

[0111] (3) preparing a 3D printing hydrogel fiber network and an antibacterial and anti-inflammatory hydrogel precursor solution;

[0112] The preparation process of the 3D printing hydrogel fiber network is as follows: using an extrusion type 3D printer, the 3D printing ink is extruded and printed according to a computer preset grid pattern (fiber distance is 800μm, and the number of printing layers is 6) (the printing temperature is 40℃), and ultraviolet light is used for irradiation during the extrusion process, so that the 3D printing hydrogel fiber network is obtained;

[0113] When the preset grid pattern is a square, the printable numerical value Pr of the shape of the 3D printing hydrogel fiber network is 0.95;

[0114] The preparation process of the antibacterial and anti-inflammatory hydrogel precursor solution is as follows: the photocrosslinking polymer b, the photoinitiator b and the antibacterial agent are added into the phosphate buffered saline solution, and stirred for 120min, so that the antibacterial and anti-inflammatory hydrogel precursor solution is obtained;

[0115] In the antibacterial and anti-inflammatory hydrogel precursor solution, the content of the photocrosslinking polymer b is 5wt%, the content of the photoinitiator b is 0.1wt%, and the content of the antibacterial agent is 0.07wt%.

[0116] (4) preparing a programmed drug release composite structure functional dressing;

[0117] Firstly, the antibacterial and anti-inflammatory hydrogel precursor solution accounts for 1 / 2 of the total volume is added into the mold, then the mold is placed at-20℃ for 10min, then the 3D printing hydrogel fiber network is placed in the center of the antibacterial and anti-inflammatory hydrogel precursor solution, finally the remaining antibacterial and anti-inflammatory hydrogel precursor solution is added, and then ultraviolet light is used for irradiation for 20min, so that the programmed drug release composite structure functional dressing is obtained.

[0118] The finally prepared programmed drug release composite structure functional dressing is composed of the antibacterial and anti-inflammatory hydrogel and the 3D printing hydrogel fiber network completely embedded in the antibacterial and anti-inflammatory hydrogel, the degradation time of the antibacterial and anti-inflammatory hydrogel is 3 days, the degradation time of the 3D printing hydrogel fiber network is 36 days, and the peeling strength between the antibacterial and anti-inflammatory hydrogel and the 3D printing hydrogel fiber network is 50cN.

[0119] Example 3

[0120] A method for preparing a programmed drug release composite structure functional dressing, the specific steps are as follows:

[0121] (1) Preparation of raw materials;

[0122] Photocrosslinking polymer a: methacrylated gelatin;

[0123] Hyaluronic acid: weight average molecular weight is 2 million g / mol;

[0124] Photoinitiator a, photoinitiator b: both are lithium phenyl (2,4,6-trimethylbenzoyl) phosphate;

[0125] Growth factor: basic fibroblast growth factor, CAS number is 106096-93-9;

[0126] Phosphate buffered saline solution: manufacturer is Beijing Wakai Biotechnology Co., Ltd., and the article number is A55535;

[0127] Photocrosslinking polymer b: methacrylated hyaluronic acid;

[0128] Antibacterial agent: genipin;

[0129] (2) Preparation of 3D printing ink;

[0130] Add photocrosslinking polymer a, hyaluronic acid, photoinitiator a and growth factor into phosphate buffered saline solution, stir for 240 min, and then 3D printing ink is obtained;

[0131] In the 3D printing ink, the mass ratio of photocrosslinking polymer a to hyaluronic acid is 15:2.5, the content of photocrosslinking polymer a is 20wt%, the content of photoinitiator a is 0.1wt%, and the content of growth factor is 30μg / mL; When no shear force is applied, the viscosity of the 3D printing ink is 10Pa·s, and the elastic modulus is 1Pa; When a shear force of 30Pa is applied, the viscosity of the 3D printing ink is 0.1Pa·s, and the elastic modulus is 0.001Pa;

[0132] (3) Preparation of 3D printing hydrogel fiber network and antibacterial and anti-inflammatory hydrogel precursor solution;

[0133] The preparation process of 3D printing hydrogel fiber network is as follows: using an extrusion type 3D printer, the 3D printing ink is extruded and printed according to the computer preset grid pattern (fiber distance is 500μm, printing layer number is 4 layers) (printing temperature is 40℃), and ultraviolet light is used for irradiation during extrusion, and then 3D printing hydrogel fiber network is obtained;

[0134] When the preset grid pattern is a square, the printable value Pr of the shape of the 3D printing hydrogel fiber network is 0.98;

[0135] The preparation process of the antibacterial and anti-inflammatory hydrogel precursor solution is as follows: the photocrosslinking polymer b, the photoinitiator b, and the antibacterial agent are added into the phosphate buffered saline solution, and stirred for 120 min, to obtain the antibacterial and anti-inflammatory hydrogel precursor solution;

[0136] In the antibacterial and anti-inflammatory hydrogel precursor solution, the content of the photocrosslinking polymer b is 3 wt%, the content of the photoinitiator b is 0.1 wt%, and the content of the antibacterial agent is 0.1 wt%;

[0137] (4) Preparation of a programmed drug release composite structure functional dressing;

[0138] First, 1 / 2 of the total volume of the antibacterial and anti-inflammatory hydrogel precursor solution is added into the mold, and then the mold is placed at -20°C for 30 min. Then, the 3D printed hydrogel fiber network is placed in the center of the antibacterial and anti-inflammatory hydrogel precursor solution. Finally, the remaining antibacterial and anti-inflammatory hydrogel precursor solution is added, and then the mixture is irradiated with ultraviolet light for 5 min, to obtain the programmed drug release composite structure functional dressing.

[0139] The finally prepared programmed drug release composite structure functional dressing is composed of the antibacterial and anti-inflammatory hydrogel and the 3D printed hydrogel fiber network completely embedded in the antibacterial and anti-inflammatory hydrogel. The degradation time of the antibacterial and anti-inflammatory hydrogel is 3 days, the degradation time of the 3D printed hydrogel fiber network is 45 days, and the peeling strength between the antibacterial and anti-inflammatory hydrogel and the 3D printed hydrogel fiber network is 100 cN.

[0140] Example 4

[0141] A preparation method of a programmed drug release composite structure functional dressing, and the specific steps are as follows:

[0142] (1) Preparation of raw materials;

[0143] The photocrosslinking polymer a is methacrylated gelatin;

[0144] The hyaluronic acid has a weight average molecular weight of 2.5 million g / mol;

[0145] The photoinitiator a and the photoinitiator b are both phenyl (2,4,6-trimethylbenzoyl) lithium phosphate;

[0146] The growth factor is basic fibroblast growth factor, and the CAS number is 106096-93-9;

[0147] The phosphate buffered saline solution is from Beijing Wake Biotechnology Co., Ltd., and the product number is A55535;

[0148] The photocrosslinking polymer b is methacrylated chitosan;

[0149] The antibacterial agent is genipin;

[0150] (2) preparing 3D printing ink;

[0151] adding the photocrosslinking polymer a, hyaluronic acid, photoinitiator a and growth factor into the phosphate buffer solution, stirring for 180 min to obtain the 3D printing ink;

[0152] In the 3D printing ink, the mass ratio of the photocrosslinking polymer a to the hyaluronic acid is 10:2.75, the content of the photocrosslinking polymer a is 10 wt%, the content of the photoinitiator a is 0.1 wt%, and the content of the growth factor is 50 μg / mL; when no shear force is applied, the viscosity of the 3D printing ink is 20 Pa·s, and the elastic modulus is 3 Pa; when a shear force of 40 Pa is applied, the viscosity of the 3D printing ink is 1.5 Pa·s, and the elastic modulus is 0.003 Pa;

[0153] (3) preparing a 3D printing hydrogel fiber network and an antibacterial and anti-inflammatory hydrogel precursor solution;

[0154] The preparation process of the 3D printing hydrogel fiber network is as follows: using an extrusion type 3D printer, the 3D printing ink is extruded and printed according to a computer preset grid pattern (fiber distance is 800 μm, and the number of printed layers is 4) (the printing temperature is 30℃), and ultraviolet light is used for irradiation during the extrusion process, to obtain the 3D printing hydrogel fiber network (the optical microscope photo is shown in Figure 1 );

[0155] When the preset grid pattern is a square, the printable numerical value Pr of the shape of the 3D printing hydrogel fiber network is 1.01;

[0156] The preparation process of the antibacterial and anti-inflammatory hydrogel precursor solution is as follows: adding the photocrosslinking polymer b, the photoinitiator b and the antibacterial agent into the phosphate buffer solution, and stirring for 120 min to obtain the antibacterial and anti-inflammatory hydrogel precursor solution;

[0157] In the antibacterial and anti-inflammatory hydrogel precursor solution, the content of the photocrosslinking polymer b is 1 wt%, the content of the photoinitiator b is 0.1 wt%, and the content of the antibacterial agent is 0.1 wt%;

[0158] (4) preparing a programmed drug release composite structure functional dressing;

[0159] Firstly, 1 / 2 of the total volume of the antibacterial and anti-inflammatory hydrogel precursor solution is added into a mold, then the mold is placed at -20℃ for 30 min, then the 3D printing hydrogel fiber network is placed in the center of the antibacterial and anti-inflammatory hydrogel precursor solution, finally the remaining antibacterial and anti-inflammatory hydrogel precursor solution is added, and ultraviolet light is irradiated for 5 min, to obtain the programmed drug release composite structure functional dressing.

[0160] The finally prepared programmed drug release composite structure functional dressing is composed of an antibacterial and anti-inflammatory hydrogel and a 3D printed hydrogel fiber network completely embedded in the antibacterial and anti-inflammatory hydrogel, the degradation time of the antibacterial and anti-inflammatory hydrogel is 7 days, the degradation time of the 3D printed hydrogel fiber network is 28 days, and the peeling strength between the antibacterial and anti-inflammatory hydrogel and the 3D printed hydrogel fiber network is 10 cN.

[0161] Example 5

[0162] A preparation method of a programmed drug release composite structure functional dressing, the specific steps are as follows:

[0163] (1) Preparation of raw materials;

[0164] Photocrosslinking polymer a: methacrylated gelatin;

[0165] Hyaluronic acid: weight average molecular weight is 1.8 million g / mol;

[0166] Photoinitiator a, photoinitiator b: both are 2-hydroxy-4'-(2-hydroxyethoxy)-2-methyl propiophenone;

[0167] Growth factor: basic fibroblast growth factor, CAS number is 106096-93-9;

[0168] Phosphate buffered saline solution: manufacturer is Beijing Wakai Biological Technology Co., Ltd., and the article number is A55535;

[0169] Photocrosslinking polymer b: methacrylated sodium alginate;

[0170] Antibacterial agent: genipin;

[0171] (2) Preparation of 3D printing ink;

[0172] The photocrosslinking polymer a, hyaluronic acid, photoinitiator a and growth factor are added into the phosphate buffered saline solution, and stirred for 120 min, to obtain the 3D printing ink;

[0173] In the 3D printing ink, the mass ratio of the photocrosslinking polymer a to the hyaluronic acid is 5:3, the content of the photocrosslinking polymer a is 12.5 wt%, the content of the photoinitiator a is 0.5 wt%, and the content of the growth factor is 40 μg / mL; when no shear force is applied, the viscosity of the 3D printing ink is 50 Pa·s, and the elastic modulus is 10 Pa; when a shear force of 10 Pa is applied, the viscosity of the 3D printing ink is 10 Pa·s, and the elastic modulus is 0.01 Pa;

[0174] (3) Preparation of 3D printed hydrogel fiber network and antibacterial and anti-inflammatory hydrogel precursor solution;

[0175] The preparation process of the 3D-printed hydrogel fiber network is as follows: using an extrusion type 3D printer, the 3D printing ink is extruded and printed according to the computer preset grid pattern (fiber distance is 1000 μm, printing layer number is 6 layers) (printing temperature is 26 ℃), and ultraviolet light is used for irradiation during the extrusion process, thereby obtaining the 3D-printed hydrogel fiber network;

[0176] When the preset grid pattern is a square, the printable numerical value Pr of the shape of the 3D-printed hydrogel fiber network is 1.05;

[0177] The preparation process of the antibacterial and anti-inflammatory hydrogel precursor solution is as follows: the photocrosslinking polymer b, the photoinitiator b and the antibacterial agent are added into the phosphate buffered saline solution, and stirred for 240 min, thereby obtaining the antibacterial and anti-inflammatory hydrogel precursor solution;

[0178] In the antibacterial and anti-inflammatory hydrogel precursor solution, the content of the photocrosslinking polymer b is 1 wt%, the content of the photoinitiator b is 0.5 wt%, and the content of the antibacterial agent is 0.05 wt%.

[0179] (4) Preparation of a programmed drug release composite structure functional dressing;

[0180] First, 2 / 3 of the total volume of the antibacterial and anti-inflammatory hydrogel precursor solution is added into the mold, and then the mold is placed at -20 ℃ for 30 min, then the 3D-printed hydrogel fiber network is placed in the center of the antibacterial and anti-inflammatory hydrogel precursor solution, and finally the remaining antibacterial and anti-inflammatory hydrogel precursor solution is added, and then ultraviolet light is irradiated for 10 min, thereby obtaining the programmed drug release composite structure functional dressing.

[0181] The finally prepared programmed drug release composite structure functional dressing is composed of the antibacterial and anti-inflammatory hydrogel and the 3D-printed hydrogel fiber network completely embedded in the antibacterial and anti-inflammatory hydrogel, the degradation time of the antibacterial and anti-inflammatory hydrogel is 7 days, the degradation time of the 3D-printed hydrogel fiber network is 32 days, and the peeling strength of the antibacterial and anti-inflammatory hydrogel and the 3D-printed hydrogel fiber network is 20 cN.

[0182] Example 6

[0183] A preparation method of a programmed drug release composite structure functional dressing, and the specific steps are as follows:

[0184] (1) Preparation of raw materials;

[0185] The photocrosslinking polymer a is methacrylated gelatin;

[0186] The hyaluronic acid has a weight average molecular weight of 2.5 million g / mol;

[0187] The photoinitiator a and the photoinitiator b are both 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone;

[0188] Growth factor: basic fibroblast growth factor, CAS No. 106096-93-9;

[0189] Phosphate buffered saline solution: manufacturer Beijing Woke Biological Technology Co., Ltd., product code A55535;

[0190] Photocrosslinking polymer b: methacrylated gelatin;

[0191] Antibacterial agent: genipin;

[0192] (2) Preparation of 3D printing ink;

[0193] Add photocrosslinking polymer a, hyaluronic acid, photoinitiator a, and growth factor into phosphate buffered saline solution, and stir for 120 min to obtain 3D printing ink;

[0194] In the 3D printing ink, the mass ratio of photocrosslinking polymer a to hyaluronic acid is 5:2.5, the content of photocrosslinking polymer a is 10wt%, the content of photoinitiator a is 0.5wt%, and the content of growth factor is 40μg / mL; when no shear force is applied, the viscosity of the 3D printing ink is 35Pa·s, and the elastic modulus is 6.5Pa; when a shear force of 50Pa is applied, the viscosity of the 3D printing ink is 7.5Pa·s, and the elastic modulus is 0.009Pa;

[0195] (3) Preparation of 3D printing hydrogel fiber network and antibacterial and anti-inflammatory hydrogel precursor solution;

[0196] The preparation process of the 3D printing hydrogel fiber network is as follows: using an extrusion type 3D printer, the 3D printing ink is extruded and printed according to the computer preset grid pattern (fiber distance is 1000μm, printing layer number is 4 layers) (printing temperature is 26℃), and ultraviolet light is used for irradiation during the extrusion process, to obtain the 3D printing hydrogel fiber network;

[0197] When the preset grid pattern is a square, the printable value Pr of the shape of the 3D printing hydrogel fiber network is 0.99;

[0198] The preparation process of the antibacterial and anti-inflammatory hydrogel precursor solution is as follows: add photocrosslinking polymer b, photoinitiator b, and antibacterial agent into phosphate buffered saline solution, and stir for 240 min to obtain the antibacterial and anti-inflammatory hydrogel precursor solution;

[0199] In the antibacterial and anti-inflammatory hydrogel precursor solution, the content of photocrosslinking polymer b is 5wt%, the content of photoinitiator b is 0.5wt%, and the content of antibacterial agent is 0.08wt%;

[0200] (4) Preparation of programmed drug release composite structure functional dressing;

[0201] Firstly, 2 / 3 of the total volume of the antibacterial and anti-inflammatory hydrogel precursor solution was added to the mold, and then it was placed at -20℃ for 10 min. Then, the 3D printed hydrogel fiber network was placed in the center of the antibacterial and anti-inflammatory hydrogel precursor solution. Finally, the remaining antibacterial and anti-inflammatory hydrogel precursor solution was added, and then it was irradiated with ultraviolet light for 10 min to obtain the programmed drug release composite structure functional dressing.

[0202] The finally prepared programmed drug release composite structure functional dressing was composed of antibacterial and anti-inflammatory hydrogel and 3D printed hydrogel fiber network completely embedded in the antibacterial and anti-inflammatory hydrogel. The degradation time of the antibacterial and anti-inflammatory hydrogel was 3 days, the degradation time of the 3D printed hydrogel fiber network was 21 days, and the peeling strength between the antibacterial and anti-inflammatory hydrogel and the 3D printed hydrogel fiber network was 10 cN.

[0203] Example 7

[0204] A preparation method of a programmed drug release composite structure functional dressing, and the specific steps are as follows:

[0205] (1) Preparation of raw materials;

[0206] Photocrosslinking polymer a: methacrylated gelatin;

[0207] Photocrosslinking polymer b: methacrylated hyaluronic acid;

[0208] Hyaluronic acid: weight average molecular weight of 1.8 million g / mol;

[0209] Photoinitiator a, photoinitiator b: both are lithium phenyl (2,4,6-trimethylbenzoyl) phosphate;

[0210] Growth factor: basic fibroblast growth factor, CAS number 106096-93-9;

[0211] Phosphate buffered saline solution: manufacturer Beijing Wakai Biological Technology Co., Ltd., product number A55535;

[0212] Antibacterial agent: genipin;

[0213] (2) Preparation of 3D printing ink;

[0214] The photocrosslinking polymer a, hyaluronic acid, photoinitiator a, and growth factor were added to the phosphate buffered saline solution, and stirred for 240 min to obtain the 3D printing ink;

[0215] The 3D printing ink has a mass ratio of the photocrosslinking polymer a to the hyaluronic acid of 10:2.75, a content of the photocrosslinking polymer a of 10 wt%, a content of the photoinitiator a of 0.1 wt%, and a content of the growth factor of 10 μg / mL; when no shear force is applied, the 3D printing ink has a viscosity of 20 Pa·s and an elastic modulus of 3 Pa; when a shear force of 40 Pa is applied, the 3D printing ink has a viscosity of 1.5 Pa·s and an elastic modulus of 0.003 Pa;

[0216] (3) preparing a 3D printing hydrogel fiber network, an antibacterial and anti-inflammatory hydrogel, and

[0217] The preparation process of the 3D printing hydrogel fiber network is as follows: using an extrusion type 3D printer, the 3D printing ink is extruded and printed according to a computer preset grid pattern (fiber distance of 500 μm, printing layer number of 6 layers) (printing temperature of 32 ℃), and ultraviolet light is used for irradiation during the extrusion process, to obtain the 3D printing hydrogel fiber network.

[0218] When the preset grid pattern is a square, the printable numerical value Pr of the shape of the 3D printing hydrogel fiber network is 0.99.

[0219] The preparation process of the antibacterial and anti-inflammatory hydrogel is as follows: the photocrosslinking polymer b, the photoinitiator b, and the antibacterial agent are added into a phosphate buffered saline solution, and stirred for 120 min, to obtain the antibacterial and anti-inflammatory hydrogel precursor solution; in the antibacterial and anti-inflammatory hydrogel precursor solution, the content of the photocrosslinking polymer b is 3 wt%, the content of the photoinitiator b is 0.1 wt%, and the content of the antibacterial agent is 0.05 wt%.

[0220] (4) preparing a programmed drug release composite structure functional dressing;

[0221] Firstly, 1 / 2 of the total volume of the antibacterial and anti-inflammatory hydrogel precursor solution is added into a mold, and then the mold is placed at -20 ℃ for 10 min; then the 3D printing hydrogel fiber network is placed in the center of the antibacterial and anti-inflammatory hydrogel precursor solution; finally, the remaining antibacterial and anti-inflammatory hydrogel precursor solution is added, and ultraviolet light is irradiated for 3 min, to obtain the programmed drug release composite structure functional dressing.

[0222] The finally obtained programmed drug release composite structure functional dressing is composed of the antibacterial and anti-inflammatory hydrogel and the 3D printing hydrogel fiber network completely embedded in the antibacterial and anti-inflammatory hydrogel; the degradation time of the antibacterial and anti-inflammatory hydrogel is 3 days, the degradation time of the 3D printing hydrogel fiber network is 28 days, and the peeling strength of the antibacterial and anti-inflammatory hydrogel and the 3D printing hydrogel fiber network is 15 cN.

[0223] Example 8

[0224] A preparation method of a programmed drug release composite structure functional dressing, the specific steps are as follows:

[0225] (1) Preparation of raw materials;

[0226] Photo-crosslinking polymer a: methacrylated gelatin;

[0227] Photo-crosslinking polymer b: methacrylated sodium alginate;

[0228] Hyaluronic acid: weight average molecular weight is 2.5 million g / mol;

[0229] Photo initiator a: lithium salt of phenyl (2,4,6-trimethylbenzoyl) phosphate;

[0230] Photo initiator b: 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone;

[0231] Growth factor: basic fibroblast growth factor, CAS number 106096-93-9;

[0232] Phosphate buffered saline solution: manufacturer Beijing Wakai Biological Technology Co., Ltd., product number A55535;

[0233] Antibacterial agent: genipin;

[0234] (2) Preparation of 3D printing ink;

[0235] Add photo-crosslinking polymer a, hyaluronic acid, photo initiator a, and growth factor to the phosphate buffered saline solution and stir for 240 min to obtain the 3D printing ink;

[0236] In the 3D printing ink, the mass ratio of photo-crosslinking polymer a to hyaluronic acid is 10:3, the content of photo-crosslinking polymer a is 10wt%, the content of photo initiator a is 0.1wt%, and the content of growth factor is 50μg / mL; When no shear force is applied, the viscosity of the 3D printing ink is 30Pa·s, and the elastic modulus is 1.5Pa; When a shear force of 50Pa is applied, the viscosity of the 3D printing ink is 5Pa·s, and the elastic modulus is 0.005Pa;

[0237] (3) Preparation of 3D printing hydrogel fiber network and antibacterial and anti-inflammatory hydrogel;

[0238] The preparation process of the 3D printing hydrogel fiber network is as follows: using an extrusion type 3D printer, the 3D printing ink is extruded and printed according to the computer preset grid pattern (fiber distance is 600μm, printing layer number is 4 layers) (printing temperature is 40℃), and ultraviolet light is used for irradiation during the extrusion process, to obtain the 3D printing hydrogel fiber network;

[0239] When the preset grid pattern is a square, the printable value Pr of the shape of the 3D-printed hydrogel fiber network is 0.98;

[0240] The preparation process of the antibacterial and anti-inflammatory hydrogel is as follows: the photocrosslinking polymer b, the photoinitiator b, and the antibacterial agent are added into the phosphate buffered saline solution, and stirred for 240 min to obtain the antibacterial and anti-inflammatory hydrogel precursor solution; in the antibacterial and anti-inflammatory hydrogel precursor solution, the content of the photocrosslinking polymer b is 1 wt%, the content of the photoinitiator b is 0.5 wt%, and the content of the antibacterial agent is 0.08 wt%.

[0241] (4) preparing a programmed drug release composite structure functional dressing;

[0242] Firstly, 1 / 2 of the total volume of the antibacterial and anti-inflammatory hydrogel precursor solution is added into the mold, and then the mold is placed at -20℃ for 30 min; then the 3D-printed hydrogel fiber network is placed in the center of the antibacterial and anti-inflammatory hydrogel precursor solution; finally, the remaining antibacterial and anti-inflammatory hydrogel precursor solution is added, and then the ultraviolet light is irradiated for 20 min to obtain the programmed drug release composite structure functional dressing.

[0243] The finally prepared programmed drug release composite structure functional dressing is composed of the antibacterial and anti-inflammatory hydrogel and the 3D-printed hydrogel fiber network completely embedded in the antibacterial and anti-inflammatory hydrogel, the degradation time of the antibacterial and anti-inflammatory hydrogel is 7 days, the degradation time of the 3D-printed hydrogel fiber network is 36 days, and the peeling strength between the antibacterial and anti-inflammatory hydrogel and the 3D-printed hydrogel fiber network is 50 cN.

[0244] Comparative Example 1

[0245] A functional dressing is prepared by the method of Example 3, and the difference is only that in step (2), the feeding ratio of the photocrosslinking polymer a and the hyaluronic acid is adjusted, and the mass ratio of the photocrosslinking polymer a to the hyaluronic acid in the 3D printing ink is 20:1; when no shear force is applied, the viscosity of the 3D printing ink is 2 Pa·s, and the elastic modulus is 0.05 Pa; when a shear force of 30 Pa is applied, the viscosity of the 3D printing ink is 0.09 Pa·s, and the elastic modulus is 1×10 -5 Pa; in step (3), when the preset grid pattern is a square, the printable value Pr of the shape of the 3D-printed hydrogel fiber network is 0.19.

[0246] Compared with Example 3, the viscosity and elastic modulus of the 3D printing ink of Comparative Example 1 are reduced, and the printable value Pr of the shape of the 3D printed hydrogel fiber network deviates from 1 significantly, because when the amount of added hyaluronic acid is too low relative to the photo-crosslinking polymer, the physical entanglement network is insufficient, resulting in low viscosity and elastic modulus of the solution, and the ink behaves as a solution state, unable to maintain a filamentous shape, and the ink is prone to dispersion or breakage during printing, making it difficult to form a continuous and regular fiber structure, ultimately resulting in a large deviation of the shape of the 3D printed hydrogel fiber network from the preset square grid.

[0247] Comparative Example 2

[0248] A method for preparing a functional dressing, and the difference from Example 5 is only that in step (2), the feeding ratio of photo-crosslinking polymer a and hyaluronic acid is adjusted, and the mass ratio of photo-crosslinking polymer a to hyaluronic acid in the 3D printing ink is 5:4; when no shear force is applied, the viscosity of the 3D printing ink is 200 Pa·s, and the elastic modulus is 5 Pa; when a shear force of 10 Pa is applied, the viscosity of the 3D printing ink is 3 Pa·s, and the elastic modulus is 300 Pa; in step (3), when the preset grid pattern is a square, the printable value Pr of the shape of the 3D printed hydrogel fiber network is 0.79.

[0249] Comparative Example 2 and Example 5, the viscosity and elastic modulus of the 3D printing ink are increased, and the printable value Pr of the shape of the 3D printed hydrogel fiber network deviates from 1 significantly, because when the amount of added hyaluronic acid is too high relative to the photo-crosslinking polymer, the properties of hyaluronic acid dominate, resulting in a significant increase in the viscosity and elastic modulus of the solution, making it difficult to extrude or even impossible to extrude, and the printed fiber structure is difficult to maintain the preset shape, resulting in a significant deviation of the shape of the 3D printed hydrogel fiber network from the preset square grid.

[0250] Comparative Example 3

[0251] A method for preparing a functional dressing, and the difference from Example 1 is only that the weight average molecular weight of hyaluronic acid is 200,000 g / mol; when no shear force is applied, the viscosity of the 3D printing ink is 0.1 Pa·s, and the elastic modulus is 1 Pa; when a shear force of 50 Pa is applied, the viscosity of the 3D printing ink is 0.02 Pa·s, and the elastic modulus is 0.0001 Pa; in step (3), when the preset grid pattern is a square, the printable value Pr of the shape of the 3D printed hydrogel fiber network is 0.45.

[0252] Compared with Example 1, the viscosity and elastic modulus of the 3D printing ink in Comparative Example 3 were reduced, and the printable value Pr of the shape of the 3D printed hydrogel fiber network deviated significantly from 1. This is because the molecular weight of hyaluronic acid is too small and the molecular chains are too short, so they cannot effectively entangle with each other to form a strong physical network. The shear thinning effect is weak and the elastic recovery is poor. It cannot quickly recover the viscosity and elastic modulus after the shear force is removed to support the printed structure, resulting in a significant deviation between the shape of the 3D printed hydrogel fiber network and the preset square grid.

[0253] Comparative Example 4

[0254] The method for preparing a functional dressing differs from Example 6 only in that: the weight-average molecular weight of hyaluronic acid is 3 million g / mol; when no shear force is applied, the viscosity of the 3D printing ink is 100 Pa·s and the elastic modulus is 15 Pa; when a shear force of 50 Pa is applied, the viscosity of the 3D printing ink is 30 Pa·s and the elastic modulus is 5 Pa; in step (3), when the preset grid pattern is square, the printable value Pr of the shape of the 3D printed hydrogel fiber network is 1.35.

[0255] Compared with Example 6, the viscosity and elastic modulus of the 3D printing ink in Comparative Example 4 were reduced, and the printable value Pr of the shape of the 3D printed hydrogel fiber network deviated significantly from 1. This is because the molecular weight of hyaluronic acid is too large, the molecular chains are too long, and the entanglement is too dense, resulting in extremely high zero-shear viscosity. Even under high shear, the viscosity cannot be reduced to a suitable range for extrusion. At the same time, the elastic recovery is extremely fast, and it may start to rebound inside the nozzle or at the exit, increasing the extrusion resistance or even causing nozzle blockage, resulting in poor printing structure accuracy. The shape of the 3D printed hydrogel fiber network deviates significantly from the preset square grid.

[0256] Comparative Example 5

[0257] A method for preparing a functional dressing differs from Example 1 only in that: hyaluronic acid is replaced with an equal mass of methacrylamide hyaluronic acid (HAMA); the weight-average molecular weight of methacrylamide hyaluronic acid is 1.5 million g / mol; in step (3), when the preset grid pattern is square, the printable value Pr of the shape of the 3D printed hydrogel fiber network is 1.27.

[0258] Compared with Example 1, the printable value Pr of the shape of the 3D printed hydrogel fiber network of Comparative Example 5 deviates from 1 significantly, because HAMA, as a photocrosslinking polymer, participates in the formation of the chemical network together with GelMA (methylacrylated gelatin) as the hydrogel base material when cured by synchronous ultraviolet irradiation during the extrusion printing process. On the one hand, this causes the crosslinking density to be too high, and the crosslinking points of the entire network to be too dense, so that the printed structure is prone to shrinkage distortion during the curing process, and cannot maintain the regular shape of the preset square grid. On the other hand, there are differences in the curing rate and curing degree of GelMA and HAMA, which complicates the curing kinetics, generates internal stress during the ultraviolet curing process, further destroys the precision of the printed structure, and ultimately causes the shape of the 3D printed hydrogel fiber network to deviate significantly from the preset square grid.

Claims

1. A programmed release composite structure functional dressing, characterized by, The antibacterial and anti-inflammatory hydrogel and the 3D printed hydrogel fiber network embedded in the antibacterial and anti-inflammatory hydrogel together constitute the antibacterial and anti-inflammatory hydrogel; The preparation process of the 3D printed hydrogel fiber network is: using an extrusion type 3D printer, the 3D printing ink is extruded and printed according to the grid pattern preset by the computer, and ultraviolet light is used for irradiation during the extrusion process, so that the 3D printed hydrogel fiber network is obtained; wherein the printing temperature is 26-40℃; The 3D printing ink comprises a hydrogel base material, hyaluronic acid, a photoinitiator and water, the hydrogel base material is a photocrosslinking polymer, the mass ratio of the photocrosslinking polymer to the hyaluronic acid is 5-15:2.5-3, and the weight average molecular weight of the hyaluronic acid is 1.5-2.5 million g / mol; The degradation time of the antibacterial and anti-inflammatory hydrogel is 3-7 days, and the degradation time of the 3D printed hydrogel fiber network is 21-45 days; The preparation method of the programmed drug release composite structure functional dressing is: first, 1 / 2-2 / 3 of the antibacterial and anti-inflammatory hydrogel precursor solution is added in the mold, then it is placed at-20℃ for 10-30min, then the 3D printed hydrogel fiber network is placed in the center of the antibacterial and anti-inflammatory hydrogel precursor solution, finally the remaining antibacterial and anti-inflammatory hydrogel precursor solution is added, and the antibacterial and anti-inflammatory hydrogel precursor solution is crosslinked, so that the programmed drug release composite structure functional dressing is obtained; The antibacterial and anti-inflammatory hydrogel precursor solution comprises 1-5wt% of a photocrosslinking polymer, 0.1-0.5wt% of a photoinitiator, 0.05-0.1wt% of an antibacterial agent and water.

2. The programmable drug release composite structure functional dressing according to claim 1, wherein, In the 3D printing ink, the content of the photocrosslinking polymer is 10-20wt%, and the content of the photoinitiator is 0.1-0.5wt%.

3. The programmable drug release composite structure functional dressing according to claim 1, wherein, The 3D printing ink further comprises 10-50μg / mL of a growth factor.

4. The programmable drug release composite structure functional dressing according to claim 1, wherein, The photocrosslinking polymer is methacrylated gelatin.

5. The programmable drug release composite structure functional dressing according to claim 1, wherein, When no shear force is applied, the viscosity of the 3D printing ink is 10-50Pa·s, and the elastic modulus is 1-10Pa; when a shear force of 10-50Pa is applied, the viscosity of the 3D printing ink is 0.1-10Pa·s, and the elastic modulus is 0.001-0.01Pa.

6. The programmable drug-in-adhesive composite structure functional dressing according to claim 1, wherein, The peel strength of the antibacterial and anti-inflammatory hydrogel and the 3D printed hydrogel fiber network is 10-100cN.

7. The programmable drug release composite structure functional dressing according to claim 1, wherein The crosslinking of the antibacterial and anti-inflammatory hydrogel precursor solution is initiated by irradiating the solution with ultraviolet light for 3-20min.

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