A hydrogel dressing, its preparation method and application

Abstract

This invention relates to the field of medical dressing technology, and discloses a hydrogel dressing, its preparation method, and its application. The hydrogel dressing is prepared by physical cross-linking of the following raw materials: 6% (w / v) anionic polysaccharide, and 1%-3% (w / v) cellulose derivatives or anionic polymers. This invention provides an advanced hydrogel dressing solution with balanced performance, adjustable function, safety, gentleness, and ease of industrialization, effectively overcoming many limitations of existing technologies and possessing significant application value in wound care.

Description

Technical Field

[0001] This invention relates to the field of medical dressing technology, and in particular to a hydrogel dressing, its preparation method and application. Background Technology

[0002] Hydrogel dressings, as an advanced wound care material, are composed of a three-dimensional polymer network with high water content. These dressings provide a moist healing environment for the wound and have been proven to effectively promote granulation tissue growth and reduce pain during dressing changes, thus becoming a standard choice in the management of acute and chronic wounds. An ideal hydrogel dressing typically needs to possess the following characteristics: excellent moisture retention and oxygen permeability, good biocompatibility, suitable mechanical strength and flexibility, and gentle yet reliable adhesion to skin tissue (i.e., remaining stable during application and painless removal without damaging newly formed tissue).

[0003] To achieve the aforementioned properties, various natural and synthetic polymers are used in the preparation of hydrogel dressings. Hyaluronic acid (HA) is particularly favored due to its biological origin, excellent moisturizing ability, and biocompatibility, making it a commonly used active ingredient in hydrogel dressings. However, hydrogel networks composed of pure HA typically suffer from inherent defects such as insufficient mechanical strength, rapid enzymatic degradation leading to structural disintegration under physiological conditions, and poor mechanical stability. These limitations significantly restrict its long-term application as a standalone dressing material. Sodium carboxymethyl cellulose (CMC-Na) is another widely used natural derivative material in wound dressings. It possesses good liquid absorption and film-forming properties, but the hydrogels formed from CMC-Na are often structurally fragile, and their moisturizing durability is less than that of HA.

[0004] To overcome the limitations of single materials, existing technologies have attempted to combine HA and CMC to combine their advantages. However, such composite systems still face a series of unresolved technical bottlenecks in practical applications, mainly manifested in the following aspects: 1. Difficulty in synergistically optimizing mechanical properties and moisturizing / absorption properties: To enhance the mechanical strength of composite hydrogels, chemical cross-linking is often required. However, the chemical cross-linking process often involves the use of cross-linking agents such as epichlorohydrin and glutaraldehyde, which may have cytotoxicity risks, posing risks of biocompatibility and residual cross-linking agents. In addition, while increasing the cross-linking density enhances network rigidity, it usually sacrifices the swelling rate of the material, resulting in a decrease in its ability to absorb exudate. It is difficult to meet the requirements of high moisturizing and high absorbency while maintaining sufficient structural strength, creating a contradiction between the two. 2. Limited functionality and lack of active intervention capabilities for complex wounds: Most traditional composite hydrogels based on HA / CMC mainly play the role of physical barrier and passive moisturizing. Faced with an increasing number of infected wounds, diabetic ulcers, and other refractory wounds, these dressings lack inherent antibacterial, anti-inflammatory, or actively cellular behavior-regulating biological functions to promote tissue regeneration, making it difficult to meet the demands of the complex healing microenvironment. 3. Insufficient regulation of tissue adhesion: Many existing products either have weak adhesion, requiring additional tape or bandages for fixation, increasing inconvenience and the risk of detachment; or they have excessively strong adhesion, easily causing mechanical damage to newly formed epithelial tissue during dressing changes, leading to patient pain and interfering with the healing process. Developing hydrogel dressings with suitable and controllable adhesion remains a challenge. 4. Poor compatibility between preparation processes and active ingredient loading: Some performance-enhancing preparation methods (such as UV-initiated polymerization and high-temperature thermal cross-linking) have relatively harsh process conditions. These conditions may not be suitable for loading light- and heat-sensitive bioactive molecules (such as certain growth factors, protein drugs, or living cells), limiting the development of hydrogel dressings towards functionalization and intelligence.

[0005] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a hydrogel dressing, its preparation method and application, in order to solve the problem of insufficient mechanical strength of existing HA or CMC hydrogel dressings.

[0007] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a hydrogel dressing comprising the following raw materials prepared by physical cross-linking: 6% (w / v) anionic polysaccharide and 1%-3% (w / v) cellulose derivative or anionic polymer.

[0008] Optionally, the anionic polysaccharide includes one or more of hyaluronic acid, sodium alginate, chondroitin sulfate, and polyglutamic acid, and the cellulose derivative or anionic polymer includes one or more of sodium carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, and sodium polyacrylate.

[0009] Optionally, the swelling ratio of the hyaluronic acid and sodium carboxymethyl cellulose is 1000-1500%.

[0010] Optionally, the anionic polysaccharide is hyaluronic acid, and the cellulose derivative or anionic polymer is sodium carboxymethyl cellulose.

[0011] Optionally, the hyaluronic acid and sodium carboxymethyl cellulose form a hydrogel matrix through hydrogen bonding.

[0012] Optionally, the raw materials of the hydrogel dressing may also include active ingredients.

[0013] Optionally, the active ingredients include antibacterial metal ions, antibiotics, growth factors, anti-inflammatory drugs, etc.

[0014] In a second aspect, the present invention provides a method for preparing the above-mentioned hydrogel dressing, the method comprising the following steps: dissolving the raw materials in a solvent and stirring to obtain the hydrogel dressing.

[0015] Optionally, the process parameters for the stirring treatment include: a stirring speed of 300 rpm, a stirring time of 24 h, and a stirring temperature of 25 °C.

[0016] A third aspect of the present invention provides the application of the above-described hydrogel dressing in the preparation of medical dressings.

[0017] The present invention has the following beneficial effects: This invention discloses a hydrogel dressing, its preparation method, and its application. Compared with existing technologies, the hydrogel dressing based on hyaluronic acid (HA) and sodium carboxymethyl cellulose (CMC-Na) composite (taking HA and CMC-Na as an example), its preparation method, and its application provided by this invention have the following significant advantages and beneficial effects: 1. Excellent comprehensive performance, solving the problem of balancing mechanical strength and moisturizing properties: This invention successfully constructs a stable three-dimensional gel network with interpenetrating or semi-interpenetrating network structures by combining a specific ratio of HA and CMC-Na and their synergistic effect, along with controllable physical cross-linking (such as hydrogen bonds and ionic bonds). While maintaining high water content (>90%) and excellent moisturizing properties, the mechanical strength, elastic modulus, and structural stability of this hydrogel are significantly improved compared to pure HA hydrogel. The resulting hydrogel dressing is flexible and elastic, able to closely conform to wounds with different contours without easily breaking or deforming, effectively overcoming the defects of poor mechanical properties and rapid degradation of traditional HA-based hydrogels. 2. Adjustable adhesion properties, achieving compatibility between reliable fixation and painless removal: Through targeted design of the composite system composition and cross-linking density, this invention can precisely control the adhesion of the hydrogel dressing to moist skin tissue. The hydrogel dressing can achieve moderate and reliable adhesion to the wound surface without the need for additional admixtures, and is not easily detached during use. More importantly, when changing the hydrogel dressing, its adhesion interface can achieve gentle and clean removal, effectively avoiding secondary damage to newly formed granulation tissue or epithelial tissue, and reducing the patient's pain during dressing changes. 3. Mild preparation process and high biocompatibility, creating conditions for functional integration: The physical cross-linking (such as ionic cross-linking and hydrogen bond enhancement) used in this invention avoids the residual risk of toxic cross-linking agents (such as glutaraldehyde) in traditional chemical cross-linking, as well as the damage to the loaded active ingredients caused by harsh conditions such as ultraviolet curing and high-temperature treatment. This gentle process not only ensures the excellent biocompatibility and safety of the final product, but also provides a universal platform for in-situ loading of various light- and heat-sensitive bioactive substances (such as antibacterial metal ions, antibiotics, growth factors, and anti-inflammatory drugs) during the preparation process, facilitating the development of smart dressings with active antibacterial, anti-inflammatory, or healing-promoting functions. 4. Strong functional scalability, enhancing the active repair capability of hydrogel dressings: Based on the aforementioned gentle process platform, this invention can easily load various therapeutic ingredients into the hydrogel network, enabling the dressing to transcend traditional passive barrier and moisturizing functions, endowing it with the ability to actively intervene in the wound microenvironment. For example, by loading Zn... 2+ Ag +Plasma provides long-lasting antibacterial effects; the introduction of epidermal growth factor (EGF) and other substances accelerates cell migration and tissue regeneration. This functional design makes it particularly suitable for treating complex and difficult-to-heal wounds such as infected wounds and chronic ulcers. 5. Simple process, good reproducibility, and promising industrialization prospects: The preparation method of this invention is simple in steps, the raw materials are readily available, the cross-linking process is mild and easy to control, and it does not rely on complex and expensive equipment. The entire process is safe, green, and highly reproducible, which is conducive to achieving stable and large-scale production, and has good prospects for technology transfer and industrial application.

[0018] In summary, this invention provides an advanced hydrogel dressing solution that is balanced in performance, adjustable in function, safe and gentle, and easy to industrialize. It effectively overcomes many limitations of existing technologies and has significant application value in the field of wound care. Attached Figure Description

[0019] Figure 1 Scanning electron microscope (SEM) images of the hydrogel dressings prepared in Examples 1-3 and Comparative Example 1.

[0020] Figure 2 The swelling ratio is the swelling rate of the hydrogel dressings prepared in Examples 1-3 and Comparative Example 1. Detailed Implementation

[0021] This invention provides a hydrogel dressing, its preparation method, and its application. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0022] This invention provides a hydrogel dressing, which is prepared by physical cross-linking of the following raw materials: 6% (w / v) anionic polysaccharide and 1%-3% (w / v) cellulose derivative or anionic polymer.

[0023] According to embodiments of the present invention, the hydrogel dressing has unique technical principles in its composition and structure, thereby producing a series of beneficial technical effects: This invention uses anionic polysaccharides (such as HA) and cellulose derivatives (such as CMC-Na) or anionic polymers as basic raw materials to prepare hydrogel dressings through physical cross-linking. Its core mechanism of action lies in the fact that both HA and CMC-Na molecular chains are rich in carboxyl groups, which endow the dressing system with inherent pH buffering capacity. Furthermore, CMC-Na, as a highly absorbent material, can efficiently absorb and lock in large amounts of liquid.

[0024] Based on the above principles, the hydrogel dressing of this invention exhibits the following outstanding effects: 1. Microenvironment regulation and healing promotion: The large number of carboxyl groups contained in the hydrogel dressing can effectively neutralize the alkaline microenvironment commonly found in infected wounds or chronic ulcers, regulating it towards a neutral physiological pH range. This creates more favorable biological conditions for cell proliferation, migration, and epithelialization, meeting the requirements of modern wet wound healing theory. 2. Excellent exudate management: Due to the high water absorption of CMC-Na, this hydrogel dressing exhibits excellent absorption performance for wounds with abundant exudate. After absorbing the liquid, the hydrogel dressing swells, generating slight physical pressure on the wound, which helps reduce edema in surrounding tissues and promotes wound healing. 3. Unity of low cost and high performance: This invention uses low-cost natural polymer raw materials such as HA and CMC, and successfully prepares hydrogel dressings through an extremely simple physical blending process (mixing yields the product). This process avoids complex chemical cross-linking processes, yet achieves performance close to or even surpassing that of some complex chemically cross-linked or synthetic polymer hydrogels, offering significant advantages in cost control. 4. High Safety and Drug Compatibility: Utilizing biocompatible natural raw materials and a physical cross-linking method, the dressing exhibits high safety in use. Simultaneously, this physical gel system provides an excellent platform for loading various drugs (especially thermosensitive or photosensitizing drugs). No chemical reaction is required; the drug solution can be conveniently mixed into the gel matrix at the final stage, enabling "ready-to-use" personalized treatment and expanding its clinical application scenarios. 5. Inspiration from a New Material Design Philosophy: This invention not only provides a specific dressing formulation but also reveals an innovative material design approach: by precisely selecting synergistic natural polymers (such as anionic polysaccharides and cellulose derivatives) and controlling their ratio (e.g., 6% to 1%-3%), the material's inherent performance potential can be maximized through simple physical blending at low concentrations, without relying on complex chemical modifications. This provides a highly attractive solution for developing low-cost, high-performance, and highly safe medical dressings, especially those suitable for primary healthcare or large-scale emergency stockpiling.

[0025] In summary, the hydrogel dressing of the present invention demonstrates significant technical advantages and application potential in regulating the wound microenvironment, managing exudate, controlling costs, adapting to drug therapy, and providing a new material design paradigm. It is worthwhile to further verify and develop it through studies such as in vitro wound models.

[0026] In some embodiments, the anionic polysaccharide includes one or more of hyaluronic acid, sodium alginate, chondroitin sulfate, and polyglutamic acid, and the cellulose derivative or anionic polymer includes one or more of sodium carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, and sodium polyacrylate.

[0027] In some embodiments, the swelling ratio of the hyaluronic acid and sodium carboxymethyl cellulose is 1000-1500%.

[0028] In some embodiments, the anionic polysaccharide is hyaluronic acid, and the cellulose derivative or anionic polymer is sodium carboxymethyl cellulose.

[0029] In some embodiments, the hyaluronic acid and sodium carboxymethyl cellulose form a hydrogel matrix through hydrogen bonding.

[0030] In some embodiments, the raw materials of the hydrogel dressing also include active ingredients.

[0031] In some embodiments, the active ingredient includes antibacterial metal ions, antibiotics, growth factors, anti-inflammatory drugs, etc.

[0032] This invention provides a method for preparing the above-mentioned hydrogel dressing, the method comprising the following steps: dissolving the raw materials in a solvent and stirring to obtain the hydrogel dressing.

[0033] The core of the preparation method provided in this invention lies in its mild conditions, simple operation, and safety. The entire process does not rely on harsh conditions such as ultraviolet light irradiation or high-temperature heating, thus fundamentally avoiding the risk of inactivation of active ingredients (e.g., in the case of drug loading) due to strong external fields. Simultaneously, since this method is a purely physical mixing process without the use of any chemical cross-linking agents, it ensures that the final product contains no toxic reagent residues, meeting the stringent biosafety requirements for medical devices. This efficient, safe, and low-energy-consumption process route makes it highly suitable for stable and controllable industrial-scale production, possessing significant advantages for industrial transformation.

[0034] In some embodiments, the process parameters of the stirring treatment include: a stirring speed of 300 rpm, a stirring time of 24 h, and a stirring temperature of 25 °C.

[0035] This invention provides the application of the above-described hydrogel dressing in the preparation of medical dressings.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0037] The following detailed description uses specific examples.

[0038] Example 1 The preparation of a hydrogel dressing includes the following steps: accurately weighing 0.6 g of HA powder and 0.1 g of CMC-Na powder, dissolving them together in deionized water, making up to 10 mL, and magnetically stirring overnight to form a homogeneous hydrogel dressing.

[0039] Example 2 The preparation of a hydrogel dressing is basically the same as that in Example 1, except that 0.6 g of HA powder and 0.2 g of CMC-Na powder are accurately weighed.

[0040] Example 3 The preparation of a hydrogel dressing is basically the same as that in Example 1, except that 0.6 g of HA powder and 0.3 g of CMC-Na powder are accurately weighed.

[0041] Comparative Example 1 The preparation of a hydrogel dressing includes the following steps: accurately weighing 0.6 g of HA powder, dissolving it in deionized water, adjusting the volume to 10 mL, and magnetically stirring until completely dissolved to obtain a homogeneous, viscous 6% HA hydrogel dressing.

[0042] Scanning electron microscope images of the hydrogel dressings prepared in Examples 1-3 and Comparative Example 1 are shown below. Figure 1 .

[0043] Performance testing The swelling ratio of the hydrogel dressings prepared in Examples 1-3 and Comparative Example 1 was tested. The swelling performance of the hydrogel dressing is a key indicator of its ability to absorb wound exudate, and it is usually quantitatively assessed by weighing. Before the experiment, the prepared hydrogel dressing was thoroughly dried and weighed as the initial mass Wd. It was then placed in phosphate buffered saline (PBS) at 37°C, simulating the physiological environment of the human body. At preset time intervals, the sample was removed with tweezers and excess moisture was gently blotted with moistened filter paper. Its wet weight Ws was immediately measured. Finally, the swelling ratio (%) was calculated using the formula: Swelling ratio (%) = (Ws) / (Wd ... The swelling rate at different time points was calculated using Wd / Wd×100%, thus plotting the water absorption kinetics curve of the dressing. The results are shown below. Figure 2 ,from Figure 2As can be seen, all groups of hydrogel dressings exhibited extremely high water absorption rates and rapidly increasing swelling rates within the first 10 minutes after contact with the liquid. This reflects the excellent hydrophilic affinity between hyaluronic acid (HA) and sodium carboxymethyl cellulose (CMC) matrix, ensuring rapid absorption of wound secretions in the initial application stage. As time progressed to 60 minutes, the curve slope gradually slowed and flattened, indicating that the three-dimensional network within the hydrogel was approaching saturation and had entered a state of physical equilibrium. Comparing the curves of different formulations clearly shows that increasing the CMC content significantly improves swelling performance: the swelling rate of the pure HA group was relatively low, remaining around 1000%, while as the CMC ratio increased from 1% to 3%, the curve shifted upwards accordingly, with the 3% CMC group exhibiting the highest swelling rate, approaching 1500%.

[0044] The main reason for this phenomenon is that CMC, as a high-molecular-weight polyelectrolyte, has carboxymethyl groups abundant in its molecular chain that generate strong osmotic pressure after dissociation in water. This drives more water into the gel network, significantly enhancing the dressing's capacity to hold liquids. This experimental result strongly demonstrates that by adjusting the CMC ratio, the water absorption performance of hydrogel dressings can be precisely optimized, enabling them to better adapt to wound care needs with varying degrees of exudation in clinical applications, maintaining wound moisture balance and effectively preventing exudate maceration.

[0045] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A hydrogel dressing, characterized in that, The hydrogel dressing is prepared by physical cross-linking of the following raw materials: 6% (w / v) anionic polysaccharide, 1%-3% (w / v) cellulose derivative or anionic polymer.

2. The hydrogel dressing according to claim 1, characterized in that, The anionic polysaccharide includes one or more of hyaluronic acid, sodium alginate, chondroitin sulfate, and polyglutamic acid, and the cellulose derivative or anionic polymer includes one or more of sodium carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, and sodium polyacrylate.

3. The hydrogel dressing according to claim 1, characterized in that, The swelling ratio of the hyaluronic acid and sodium carboxymethyl cellulose is 1000-1500%.

4. The hydrogel dressing according to claim 2, characterized in that, The anionic polysaccharide is hyaluronic acid, and the cellulose derivative or anionic polymer is sodium carboxymethyl cellulose.

5. The hydrogel dressing according to claim 4, characterized in that, The hyaluronic acid and sodium carboxymethyl cellulose form a hydrogel matrix through hydrogen bonding.

6. The hydrogel dressing according to claim 1, characterized in that, The raw materials of the hydrogel dressing also include active ingredients.

7. The hydrogel dressing according to claim 5, characterized in that, The active ingredients include one or more of the following: antibacterial metal ions, antibiotics, growth factors, and anti-inflammatory drugs.

8. A method for preparing the hydrogel dressing according to any one of claims 1-7, characterized in that, The preparation method includes the following steps: dissolving the raw materials in a solvent and stirring to obtain the hydrogel dressing.

9. The method for preparing the hydrogel dressing according to claim 8, characterized in that, The process parameters for the stirring treatment include: stirring speed of 300 rpm, stirring time of 24 h, and stirring temperature of 25 °C.

10. The use of the hydrogel dressing according to claims 1-7 in the preparation of medical dressings.

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