Recombinant collagen-polysaccharide dressing and preparation method thereof

Abstract

The invention provides a recombinant collagen-polysaccharide dressing and a preparation method thereof. The dressing comprises recombinant humanized III-type collagen doped with 5-20% of VII-type or I-type collagen, and sodium hyaluronate, modified chitosan, a humectant and an auxiliary agent, the collagen is partially PEGylated and forms a layered network with the polysaccharide; the inner layer is collagen-HA-sacrificial network gel, and anti-fibrosis lipidosome is encapsulated so as to realize short-term release and fitting repair; the outer layer is a modified chitosan-HAMA / PEG film forming layer, has relatively high crosslinking density and slow degradation performance, provides mechanical support, has interfaces connected through hydrolyzable Schiff-base or ester bonds, and is self-dissociated within 7-10 days to promote tissue remodeling, and the dressing has good wettability, film forming-gel matching performance and long-acting stability.

Description

Technical Field

[0001] This invention belongs to the field of medical dressing technology, specifically relating to a composite dressing with recombinant humanized collagen and modified polysaccharides as the core and its preparation method. It is intended for use in the repair of sensitive skin after medical aesthetic procedures (such as microneedling, fractional laser, radiofrequency, photon, etc.), taking into account both short-term acute anti-allergy and medium- to long-term scar suppression and long-term repair functions. Background Technology

[0002] As a crucial physical barrier protecting the body from environmental damage, the integrity of the skin is essential for maintaining physiological homeostasis. Skin damage not only disrupts the epidermal tissue and vascular network but can also lead to the disintegration of the dermal structure, causing potential health risks such as infection, inflammation, and scarring. Traumatic and infected skin injuries are common clinical problems. Wound dressings, as temporary protective barriers, effectively isolate external stimuli, maintain a moist microenvironment, and provide ideal conditions for tissue repair. Recombinant collagen, with its excellent biocompatibility, low immunogenicity, and controllability, has become a core component of wound repair dressings.

[0003] However, in applications such as sensitive skin after cosmetic surgery, existing technologies still have the following key defects that urgently need to be overcome: First, the collagen components themselves are not stable enough: recombinant collagen is easily degraded rapidly by matrix metalloproteinases (MMPs) in vivo, resulting in a short biological activity window (usually lasting only 3-5 days), which makes it difficult to meet the needs of medium- and long-term wound repair and limits its clinical efficacy.

[0004] Secondly, the degradation rate is severely unbalanced when compounded with polysaccharides: when recombinant collagen is mixed with polysaccharides (such as hyaluronic acid and chitosan) to form a dressing, the rapid degradation of collagen (within a few days) and the slow degradation of polysaccharides (within a few weeks) lead to the breakdown of functional synergy - early loss of collagen activity, which cannot play a role in promoting repair; later accumulation of polysaccharide residues, which hinders the migration of wound cells and affects the healing process.

[0005] Third, the gel-film-forming properties of polysaccharides clash significantly when combined with them: while high-water-content gels are beneficial for wound moisturizing, they offer weak support and are prone to falling off; whereas rigid gels formed by polysaccharides (such as carboxymethyl chitosan) are excessively hardened, significantly reducing the dressing's fit and breathability. When the two are combined, the flexibility required by the gel and the film-forming tendency of the polysaccharides are mutually antagonistic, resulting in a dressing that cannot simultaneously maintain a moist environment and provide long-term physical protection.

[0006] The aforementioned technical problems (poor collagen stability, asynchronous degradation of compound materials, and gel-film formation conflict) collectively restrict the application effectiveness of existing dressings in post-medical aesthetic repair. Therefore, there is an urgent need in this field to develop a novel composite dressing system that, through material modification, precisely controls collagen stability, optimizes the matching of polysaccharide-collagen degradation kinetics, and balances gel flexibility and film-forming support, achieves synergistic functions of short-term anti-inflammatory and long-term tissue regeneration, and develops composite dressing materials and preparation methods that can provide both short-term acute function and long-term support. Summary of the Invention

[0007] To address the aforementioned technical challenges, this invention proposes a layered composite system. The core consists of recombinant humanized collagen (partially PEGylated and low-toxicity cross-linked) and modified polysaccharides. At the molecular level, two types of controllable bonds (fast-response degradable bonds + stable covalent bonds) are employed to achieve phased functional release and degradation rate matching. The formulation also incorporates anti-fibrotic components and moisturizing factors to achieve a comprehensive effect of short-term acute anti-allergy, medium- to long-term barrier reconstruction, and scar suppression. The preparation method combines mild chemical modification (PEGylation, Genipin low-toxicity cross-linking, EDC / NHS covalent bonding) with physical assembly.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a recombinant collagen-polysaccharide dressing, comprising the following components:

[0009] Recombinant collagen 0.5–2.0%;

[0010] Sodium hyaluronate 0.8–2.0%;

[0011] Modified chitosan 0.5–3.0%;

[0012] Moisturizer content: 3.1–8.4%;

[0013] Other additives accounted for 85.1-88.0%;

[0014] The other additives include anti-fibrotic actives, solvents, thickeners, and crosslinking agents;

[0015] The recombinant collagen is humanized type III collagen, mixed with a small amount of type VII or type I collagen;

[0016] The small amount refers to 5–20% of the total recombinant collagen; the expression system is derived from Pichia pastoris;

[0017] Modified chitosan includes at least one of carboxymethyl chitosan, succinylated chitosan, or quaternized chitosan;

[0018] In this process, collagen is partially PEGylated and forms an interpenetrating network or layered complex structure with the modified polysaccharide through two types of cross-linking bonds. The PEGylation rate is 5–15% (based on the percentage of the number of reactive amino groups in collagen), and the molecular weight of the PEG used is 2–10 kDa.

[0019] By adopting the above technical solutions, recombinant humanized type III collagen is combined with type VII or type I collagen. Type III collagen can promote flexible reconstruction of the dermis and reduce rigid scars; type VII collagen can enhance the epidermal-dermal connection and improve epithelial adhesion and healing edge stability; type I collagen can improve tissue mechanical integrity and overall tensile strength, making it suitable for deep wounds that require higher mechanical support. The combination of type III collagen as the main flexible regeneration agent and a small amount of type VII collagen to restore the epidermal-dermal connection (or a small amount of type I collagen to improve strength) can achieve a regeneration path of "orderly reconstruction rather than extensive fibrosis", thus taking into account both short-term adhesion and medium- to long-term scar suppression effects. The addition of 5–20% trace amounts of high-functioning collagen can significantly improve healing quality without significantly increasing immune risks or costs.

[0020] Preferably, the moisturizer includes one of glycerin, allantoin, or a vitamin C derivative.

[0021] Preferably, the crosslinking system comprises at least one cleavable crosslinker containing an MMP-sensitive linker; and at least one chemical crosslinking agent, the crosslinking agent comprising at least one of EDC, NHS, or HAMA.

[0022] Furthermore, the chemical crosslinking agent is an EDC / NHS coupling system and / or a single HAMA photocrosslinking system; the amount of the chemical crosslinking agent added is 0.05–0.20 molar ratio calculated based on the carboxyl groups of the recombinant collagen.

[0023] Furthermore, the MMP-sensitive linker is capable of recognizing and cleaving at least one of the following matrix metalloproteinases: MMP-1, MMP-2, MMP-9, MMP-13, and the molar ratio of the enzyme-cleavable crosslinkers, in terms of the molar ratio to the collagen carboxyl group, is 0.001–0.050.

[0024] Preferably, the antifibrotic active ingredient includes one of asiaticoside, glycyrrhizic acid, or calcitriol.

[0025] Preferably, the thickener comprises gelatin or low-crosslinked alginate.

[0026] Preferably, the solvent is purified water or an aqueous solution containing a small amount of ethanol.

[0027] This invention also provides a method for preparing the recombinant collagen-polysaccharide dressing, which employs a layered wet production method and includes the following steps: inner layer gel, outer layer film formation and lamination, specifically:

[0028] 1) At 4–8°C, recombinant collagen, preferably 1.0 wt%, relative to the total mass of the inner gel, is dissolved in borate buffer, using purified water as solvent, pH=6.0, and gently stirred until homogeneous; before or during dissolution, NHS-PEG, with a molecular weight of 2–10 kDa, is added at a target PEGylation rate of 5–15% of the collagen reactive amino groups, and reacted at pH=7.0–8.0 for 30–120 min to partially PEGylate the recombinant collagen;

[0029] 2) Add sodium hyaluronate, thickener, and moisturizer to the PEGylated collagen solution, preferably 1.5 wt% sodium hyaluronate, 1.5 wt% gelatin, and 5.0 wt% glycerin, with purified water or water containing a small amount of ethanol, wherein the small amount is defined as 0.1-5 wt% ethanol content, and stir the solvent to make the solution homogeneous.

[0030] 3) Slowly add the suspension containing anti-fibrotic active ingredients prepared into liposomes, with a final content of 0.05 wt%, and stir at low speed for 10–20 min;

[0031] 4) Adjust the pH to 6.0 and let it stand at 10°C until a weak gel forms or a physical gel structure forms after a brief and gentle cooling.

[0032] 5) Prepare the outer film-forming solution, using a modified chitosan solution, preferably 2.0 wt% succinyl carboxymethyl chitosan and 0.8 wt% HAMA with 10% DOF as the base, and purified water or an aqueous solution containing a small amount of ethanol as the solvent. PEG-diacid (molecular weight 2–10 kDa) can be added as a bridging agent. The molar ratio of PEG-diacid to collagen carboxyl groups is 0.01–0.10. Stir until homogeneous.

[0033] 6) Add chemical crosslinking agent (EDC / NHS) or HAMA alone to the outer film-forming solution as needed for photocrosslinking; if the EDC / NHS coupling system is used, the total molar ratio of EDC / NHS added is 0.05–0.20 based on collagen carboxyl groups, and mix at room temperature for 10–30 min;

[0034] 7) Coat or spray the obtained outer film-forming liquid evenly onto the surface of the inner gel obtained in step 4), and perform chemical curing at room temperature or low-intensity photocuring when using HAMA, with a curing time of 30–120 min.

[0035] The above technical solution involves an inner and outer layer composite. In step 4), an inner layer is formed, and the surface contact layer / functional gel is mainly composed of collagen + HA + sacrificial network. Low-density physical crosslinking or mild chemical crosslinking is used, and liposomes or microspheres are encapsulated for short-term release. In step 7), the outer layer forms a continuous high-crosslink density film or electrospun web, which provides mechanical support and achieves slow degradation ≥14d. Temporary connections are formed at the inner and outer layer interfaces through partial imine bonds or short-chain hydrolyzable ester bonds. The interface connectors are hydrolyzed or enzymatically broken within 7–d, thereby achieving early synergy and late separation of the inner and outer layers.

[0036] The beneficial effects of this invention are:

[0037] 1) Staged function: Through molecular-level modification (PEGylation, MMP-sensitive linkers, aldehyde / enoyl polysaccharide) in the layered structure, the time distribution of short-term acute release and long-term mechanical support is achieved, which solves the problem of degradation rate mismatch.

[0038] 2) It adopts a layered structure with a highly hydrated inner layer and a highly cross-linked outer layer, ensuring both good adhesion and external film-forming support, thus solving the problem of conflicting gel and film-forming properties that often occurs when collagen and polysaccharide are combined:

[0039] 3) Scar suppression and long-term repair: It uses a multi-type humanized collagen complex, PEGylation to prolong activity, and is compounded with anti-fibrotic factors such as Centella asiatica extract to promote orderly collagen remodeling and reduce the risk of scar formation;

[0040] 4) Hypoallergenic formulation: Through chitosan modification, selection of de-irritating excipients and pH control, a low-irritant formula suitable for sensitive skin is achieved. Attached Figure Description

[0041] Figure 1 Examples 1-4 show comparative curves of the changes over time in a single efficacy index synthesized by weighting the healing rate, histology, scar removal reverse score, and IL-6 / TNF-α reverse score; wherein the healing rate is 40%, histology is 20%, scar removal reverse score is 20%, IL-6 is 10%, and TNF-α is 10%. Detailed Implementation

[0042] The present invention will be further described below through specific embodiments. To make the inventive objectives, technical solutions, and beneficial technical effects of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the embodiments described in this specification are merely for explaining the present invention and are not intended to limit the present invention.

[0043] Unless otherwise stated, all films and reagents used in the examples are commercially available or synthesized using conventional methods and can be used directly without further processing, as are the instruments used in the examples.

[0044] Example 1:

[0045] The dressing consists of:

[0046] Inner layer (functional gel): 1.0 wt% recombinant type III collagen (expressed by Pichia pastoris, PEGylation rate 10%, NHS-PEG 2kDa), 1.5 wt% sodium hyaluronate, 1.5 wt% gelatin, 5.0 wt% glycerol, 0.05 wt% asiaticoside (encapsulated in liposomes) (based on total liposome solids), solvent: purified water (balance).

[0047] Outer layer (film-forming / support layer): Modified chitosan is 2.0 wt% succinyl carboxymethyl chitosan.

[0048] HAMA 0.8wt% (DOF 10%) and PEG-diacid (2kDa) 0.05–0.1mol (relative to collagen carboxyl groups) were used as bridging and chemical crosslinking agents: EDC / NHS (based on a collagen carboxyl group molar ratio of 0.10).

[0049] Solvent: Purified water or water containing 1 wt% ethanol;

[0050] Preparation steps:

[0051] 1) Recombinant type III collagen (1.0 wt%) expressed by Pichia pastoris was dissolved in a borate buffer (pH 6.0) at 4–8 °C. NHS-PEG (2 kDa) was added before dissolution to achieve a target PEGylation rate of 10%, and the reaction was carried out at pH 7.5 for 60 min to partially PEGylate the collagen.

[0052] 2) Add HA (1.5wt%), gelatin (1.5wt%), and glycerol (5.0wt%) to the PEGylated collagen solution and mix thoroughly. Slowly add liposomes containing asiaticoside (0.05wt%) and stir for 10–20 min. Adjust the pH to 6.0 and incubate at 10°C until a weak gel forms (inner layer).

[0053] 3) Preparation of the outer layer: Dissolve 2.0 wt% succinyl carboxymethyl chitosan and 0.8 wt% HAMA in purified water, add EDC / NHS, and mix at room temperature for 10–30 min at a collagen carboxyl group ratio of 0.10 to obtain the film-forming solution.

[0054] 4) Coat the outer film-forming solution evenly onto the inner surface and chemically cure at room temperature for 60 min to form an outer thin film and form a partial Schiff-base bond at the interface.

[0055] 5) Packaging / Aseptic treatment.

[0056] Example 2:

[0057] Inner layer:

[0058] Recombinant type III collagen 1.0 wt%, PEGylation rate 8%, NHS-PEG 5kDa;

[0059] Sodium hyaluronate 1.2 wt%;

[0060] 1.2 wt% of low-crosslinked alginate ("low-crosslinking" target 5–10%);

[0061] Glycerin 4.0 wt%

[0062] Glycyrrhizic acid-encapsulated microspheres 0.05 wt%;

[0063] Outer layer:

[0064] Modified chitosan (quaternized chitosan) 1.8 wt%;

[0065] HAMA 1.0wt% (DOF 10%)

[0066] Solvent: Water containing 0.5 wt% ethanol.

[0067] Preparation steps:

[0068] Recombinant collagen was reacted with NHS-PEG (5kDa) at pH 7.5 for 45 min, with a PEGylation rate of 8%.

[0069] Dissolve PEGylated collagen, HA, and low-crosslinked alginate (first crosslink with 10–20 mM CaCl2 for a short time of 30–60 s to control the degree of crosslinking at 5–10%), add glycerol and glycyrrhizic acid microspheres, and let stand to form an inner layer gel (10℃).

[0070] An outer layer of HAMA / quaternary ammonium chitosan mixed solution was prepared and coated onto the inner layer. The film was then crosslinked for 30–60 min using a low-energy 365nm light source (intensity ≤10mW / cm²).

[0071] The surface / interface is temporarily linked via Schiff-base; the low-crosslinked alginate is rapidly degraded in vivo and releases glycyrrhizic acid for early anti-inflammatory effects.

[0072] Example 3:

[0073] Inner layer: 0.9wt% recombinant type III collagen (PEGylation rate 12%, NHS-PEG 2kDa), 1.5wt% HA, 1.2wt% gelatin, 6.0wt% glycerol, and 0.05wt% centella asiatica liposomes.

[0074] Outer layer: 2.0 wt% succinylated chitosan, 0.08 PEG-diacid (4 kDa) bridging molar ratio (relative to collagen carboxyl groups), 0.08 EDC / NHS molar ratio; solvent is purified water.

[0075] Collagen blending: 15% type VII collagen is added to the total collagen (i.e., III:VII = 85:15).

[0076] Preparation steps:

[0077] PEGylated collagen (12%) was reacted at pH 7.5 for 90 min.

[0078] Prepare the inner layer and allow it to stand to form a gel.

[0079] The outer layer is prepared by a succinyl chitosan + PEG-diacid + EDC / NHS solution, reacted at room temperature, coated and chemically cured for 60–120 min.

[0080] The interface is temporarily linked by short-chain ester bonds (formed by PEG-diacid and chitosan hydroxyl / collagen amino groups).

[0081] Example 4:

[0082] Inner layer: 1.2 wt% recombinant type III collagen (5% PEGylation, 2 kDa NHS-PEG), 1.8 wt% HA, 2.0 wt% low cross-linked alginate (target cross-linking degree 15–20%), 5.0 wt% glycerol, 0.05 wt% calcitriol microspheres.

[0083] Outer layer: Quaternized chitosan 2.5wt%, HAMA 0.6wt%, Genipin 0.02wt% (for mild cross-linking of the main scaffold to prolong overall stability);

[0084] Preparation steps:

[0085] After PEGylation (5%), an inner layer was prepared and the degree of alginate crosslinking was adjusted by CaCl2 thin-layer crosslinking (using 25–50 mM CaCl2, crosslinking for 60–180 s to achieve 15–20%).

[0086] The microspheres are dispersed and allowed to stand to form a gel.

[0087] The outer layer solution contains Genipin (0.02 wt%) and HAMA, and is coated and cured in a dual chemical / photocrosslinking process at room temperature for 60–120 min, followed by 24 h of weak chemical curing to enhance the strength of the main scaffold.

[0088] The collagen-polysaccharide dressings and preparation methods involved in Examples 1-4 need to be verified for their effectiveness. The test methods and conditions are as follows:

[0089] I. Outer layer tensile strength

[0090] Method: Flat / strip specimens, tensile testing machine (Instron), room temperature, tensile rate 10 mm / min, maximum tensile stress (MPa) was measured.

[0091] Samples: outer membrane samples were prepared separately or tested after being peeled from the composite (n≥5, report mean ±SD).

[0092] II. Inner layer shear modulus

[0093] Methods: Dynamic shear viscoelasticity test (Rheometer), parallel plate mode, frequency sweep (0.1–10 Hz), record G' (shear modulus); or measure the linear modulus (kPa) by small amplitude vibration.

[0094] Sample: Wet inner layer gel, temperature 37°C, n≥5.

[0095] III. In vitro enzymatic hydrolysis test (degradation curve)

[0096] Conditions: The sample was placed in a buffer containing 1 U / mL MMP (e.g., recombinant human MMP-9 or universal protease) (pH 7.4, 37°C), and weighed and the residual mass was measured at specified time points (0, 1, 3, 5, 7, 14, 21, 28d).

[0097] Output: Plot the remaining quality (%) vs. time curve, and read the time of 50% quality loss.

[0098] Note: A control group (without enzymes) was tested in parallel to distinguish between hydrolysis and enzymatic degradation.

[0099] IV. Release curve (anti-fibrotic active substances)

[0100] Conditions: Samples were placed in PBS (pH 7.4) or simulated body fluid containing MMP (37°C) and sampled at specified time points (e.g., 0, 6, 12, 24, 48, 72 h, 7, 14, 21, 30 d).

[0101] V. Thermal stability / High-temperature preservation of residual collagen

[0102] Conditions: The sample was stored in a 55°C incubator for 20 days. After removal, the residual "bioactive collagen" or "collagen content" was measured.

[0103] The results are shown in the table below:

[0104] Example 1 Example 2 Example 3 Example 4 Outer layer tensile strength 0.10–0.18 MPa 0.12–0.20 MPa 0.12–0.22 MPa 0.15–0.28 MPa Inner layer shear modulus 2–6 kPa 1.5–5 kPa 2–7 kPa 3–9 kPa Degradation (50% mass loss) @ 1 U / mL MMP 3–6 days (rapid enzymatic hydrolysis of gelatin) 2–5 days (low-crosslinked alginic acid works faster) 4–7 days (gelatin / formula slightly delayed) 6–10 days (higher degree of cross-linking → slightly longer) Main stent degradation (50% mass loss) @ 1 U / mLMMP 14–21d 14–20d 16–28d 20–35d Released in 72 hours (with anti-fibrotic active substances) 55–75% 60–80% 50–70% 45–65% 30-day cumulative release (of anti-fibrotic active substances) 85–95% 85–95% 80–92% 80–90% Heat-stable / high-temperature stored residual collagen 82–90% (PEGylation for stabilization) 80–88% 83–91% 86–95% (Genipin stabilization) Overall annotation (judging its merits / demerits) Balanced approach, chemically coupled for stability, moderately rapid release Rapid release, good photocrosslinking film formation, and low residual chemicals Greater emphasis is placed on epithelial stability and medium- to long-term support. Long-term support and good thermal stability make it suitable for deep repair.

[0105] In summary, PEGylation, Genipin, or higher chemical cross-linking can improve the thermal stability and enzyme resistance of the scaffold, while low-cross-linked alginate or gelatin, as sacrificial networks, can provide short-term rapid degradation and burst release.

[0106] Adding MMP-sensitive linkers to the crosslinking system enables local enzymatic cleavage when MMP levels are high in the early stages of the wound, thereby promoting the on-demand release of the inner sacrificial network and the encapsulated drug.

[0107] The preferred approach is to use type III as the main component (80–95%) + 5–20% of type VII or type I. This micro-incorporation strategy can significantly improve healing quality without significantly altering immunogenicity or cost: type VII enhances DEJ reconstruction, type I improves the mechanical strength of the main scaffold, and type III dominates flexible regeneration and inhibits coarse scarring.

[0108] The interface uses hydrolyzable chemical bonds (such as imine / Schiff bases or short-chain esters) as temporary links, aiming to break them within 7–10 days. This ensures early synergy of the inner layers and subsequent decoupling of the inner and outer layers for tissue remodeling.

[0109] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A recombinant collagen-glycosaminoglycan dressing, characterized in that, It includes the following components: Recombinant collagen 0.5–2.0%; Sodium hyaluronate 0.8–2.0%; Modified chitosan 0.5–3.0%; Moisturizer content: 3.1–8.4%; Other additives accounted for 85.1-88.0%; The other additives include anti-fibrotic actives, solvents, thickeners, and crosslinking systems; The recombinant collagen is humanized type III collagen, mixed with a small amount of type VII or type I collagen; Modified chitosan includes at least one of carboxymethyl chitosan, succinylated chitosan, or quaternized chitosan.

2. The recombinant collagen-glycosaminoglycan dressing of claim 1, wherein, The moisturizer includes one of glycerin, allantoin, or a vitamin C derivative.

3. The recombinant collagen-glycosaminoglycan dressing of claim 1, wherein, The crosslinking system comprises at least one cleavable crosslinker containing an MMP-sensitive linker; and at least one chemical crosslinking agent, including at least one of EDC, NHS, or HAMA.

4. The recombinant collagen-glycosaminoglycan dressing of claim 3, wherein, The amount of chemical cross-linking agent added is 0.05–0.2 molar ratio based on the carboxyl group of the recombinant collagen; the MMP-sensitive linker can be recognized and cleaved by at least one of the following matrix metalloproteinases: MMP-1, MMP-2, MMP-9, MMP-13.

5. The recombinant collagen-glycosaminoglycan dressing of claim 1, wherein, The antifibrotic active ingredient includes one of asiaticoside, glycyrrhizic acid, or calcitriol.

6. The recombinant collagen-glycosaminoglycan dressing of claim 1, wherein, The thickener includes gelatin or low-crosslinked alginate.

7. The recombinant collagen-glycosaminoglycan dressing of claim 1, wherein, The solvent is purified water or an aqueous solution containing a small amount of ethanol.

8. A method of preparing a recombinant collagen-glycosaminoglycan dressing according to any one of claims 1 to 7, characterized in that, The wet-state method using a stratified approach includes the following steps: 1) Dissolve recombinant collagen in buffer solution at 4–8℃ and stir gently until homogeneous. Before or during dissolution, add NHS-PEG and react at pH 7.0–8.0 for 30–120 min to partially PEGylate the recombinant collagen. 2) Add sodium hyaluronate, thickener, and moisturizer to the PEGylated collagen solution, using purified water or water containing a small amount of ethanol as the solvent, and stir to make the solution homogeneous; 3) Slowly add the suspension containing anti-fibrotic active ingredients prepared into liposomes and stir at low speed for 10–20 min; 4) Adjust the pH to 6.0 and let it stand at 10°C until a weak gel forms; 5) Prepare the outer film-forming solution based on modified chitosan solution and HAMA, using purified water or ethanol aqueous solution as solvent, add PEG-diacid as bridging agent, and stir evenly. 6) Add EDC / NHS or a single HAMA photocrosslinking agent to the outer film-forming solution and mix at room temperature for 10–30 min; 7) Coat or spray the outer film-forming liquid uniformly onto the surface of the inner gel obtained in step 4), and crosslink it at room temperature to form a continuous film on the outer layer and create a weak chemical bond with the interface of the inner layer.

9. The production method according to claim 8, characterized by, The weak chemical linkage in step 7) is an imine bond or an ester bond.

10. The preparation method according to claim 8, characterized in that, In step 2), a small amount of ethanol is present, ranging from 0.1 to 5 wt%.

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