A gelatinizable cellulose composite sponge and preparation method thereof

Abstract

The invention discloses a gelable cellulose composite sponge and a preparation method thereof, wherein the cellulose includes methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium carboxymethyl cellulose and cellulose acetate butyrate, etc.; the preparation method of the gelable cellulose composite sponge is vacuum freeze drying and thermal cross-linking. The cellulose sponge prepared by the invention does not use a chemical cross-linking agent, has good biocompatibility, can rebound after compression, is very suitable for nasal and sinus packing hemostasis, loses support force and becomes fluid in 24-48 hours in a physiological environment, completely degrades in 96-120 hours, can flow out naturally, and reduces secondary damage when the packing is removed.

Description

Technical Field

[0001] The invention relates to a gelatinizable cellulose composite sponge and a preparation method thereof, and belongs to the field of biomedical materials. Background Art

[0002] Functional endoscopic sinus surgery (FESS) is a minimally invasive procedure for severe sinus diseases. Postoperatively, a sponge is typically placed in the nasal cavity to control bleeding, prevent adhesions, and aid wound healing. Commonly used medical sponge materials include gelatin, polyvinyl alcohol, polyurethane, chitosan, and cellulose. Based on their raw material source, they can be categorized as animal-derived, plant-derived, and synthetic polymers. Gelatin and chitosan are animal-derived, cellulose is plant-derived, and polyvinyl alcohol and polyurethane are synthetic polymers. Based on their degradability, they can be categorized as either degradable or non-degradable. Polyvinyl alcohol sponges are generally non-degradable, have high compression strength, good expansion elasticity, and are inexpensive, making them widely used clinically. However, these sponges must be removed after hemostasis is achieved, which can cause secondary damage and significant pain to the patient. Degradable ear and nose hemostatic sponges (nanoabsorbent sponges) are made of polyurethane and have suitable elasticity. They degrade in the nasal cavity, losing their support and allowing fragments to be expelled with nasal secretions. However, their preparation is difficult, the degradation products are complex, and there is a risk of tissue absorption. Furthermore, they are expensive. Biodegradable medical gelatin sponges are relatively soft and lack elastic expansion, resulting in poor wound compression and hemostasis effects. They also have a long degradation cycle in the body. Chitosan derivative sponges have good fluid absorption properties, but generally have poor mechanical properties and lack strong elastic support, making them ineffective in addressing clinical issues. Furthermore, chitosan materials carry certain biological risks.

[0003] Cellulose has excellent biocompatibility and mechanical properties and is widely used in clinical practice. Although cellulose is hydrophilic, its high inter- and intramolecular hydrogen bonding and van der Waals forces make it difficult to dissolve and further process into hydrogels and sponges. Chemical reactions to generate various derivatives, such as carboxymethyl cellulose and hydroxyethyl cellulose, are an important approach to improving the processing properties of cellulose materials.

[0004] Nasal packing sponges made primarily from cellulose derivatives typically require the use of chemical crosslinkers such as aldehydes, which are highly carcinogenic. The present invention uses cellulose derivatives as the primary material, without aldehyde crosslinkers, and solely uses water as the solvent. The process involves swelling at a specific temperature, followed by vacuum freeze drying and subsequent vacuum heat crosslinking. This simple and controllable process yields a gelled cellulose composite sponge that meets the requirements for nasal packing and hemostasis in terms of degradation resistance, liquid absorption, and compressive strength. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention provides a gelable cellulose composite sponge and its production method. The resulting gelable cellulose composite sponge loses its holding power within two days in a physiological environment, making it easy to flush out of the body. It also boasts a high expansion coefficient and an adjustable liquid absorption rate between 10 and 40 times. It can be cut and bent for use, and boasts a 50% compressive strength of 2.0 to 12.0 kPa. Furthermore, this product avoids both direct and potential harm to the human body from crosslinking agents (primarily aldehydes).

[0006] The technical solutions of the present invention are as follows:

[0007] A gelable cellulose composite sponge and a preparation method thereof, characterized in that the preparation process of the cellulose sponge includes dissolution of a cellulose system, vacuum freeze drying and thermal cross-linking; the cellulose system includes methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium carboxymethyl cellulose and cellulose acetate butyrate, etc.; the cellulose system is dissolved using hot water and mixed in steps according to the characteristics of the cellulose modification group, and defoaming is required at a specific temperature.

[0008] The properties of the cellulose sponge include liquid absorption rate, compression strength and degradation performance.

[0009] The liquid absorption rate of the cellulose sponge is 10 to 40 times.

[0010] The compressive strength (50% deformation) of the cellulose sponge is 2-12 kPa.

[0011] The cellulose sponge can gel in physiological saline, lose its supporting force and become fluid in 24-48 hours, and completely degrade in 96-120 hours.

[0012] The method for preparing a gelable cellulose composite sponge is characterized in that the method comprises the following steps: (1) dissolution: weighing a portion of the cellulose raw material, adding it to hot water at 70-90°C, mechanically stirring until the cellulose is fully swollen, cooling the solution to 10-60°C, adding the remaining cellulose components, and fully mixing at 20-90°C until a cellulose solution with a solid content of 1-5% is formed; (2) defoaming: taking the cellulose solution prepared in step (1) and keeping it warm at 20-95°C for defoaming; (3) vacuum freeze drying: taking the solution prepared in step (2) and pouring it into a mold, vacuum freeze drying it, and obtaining a porous sponge; (4) thermal crosslinking: taking the porous sponge obtained in step (3) and performing thermal crosslinking treatment in a vacuum oven, and vacuum thermal crosslinking treatment at 50-150°C for 2-24 hours; (5) aging: after cooling, packaging the sponge and aging it for 2-120 hours to obtain a gelable cellulose composite sponge.

[0013] The beneficial technical effects of the present invention are:

[0014] (1) The cellulose sponge product prepared in this application has adjustable liquid absorption performance, with a liquid absorption rate of 10 to 40 times;

[0015] (2) The cellulose sponge product prepared in this application has moderate compression strength, provides strong patient comfort, and has a compression strength of 2.0-12.0 KPa;

[0016] (3) The cellulose sponge product prepared in this application can gel in normal saline, lose its support force and become fluid after 24 to 48 hours, and completely degrade after 48 to 120 hours;

[0017] (4) The cellulose sponge product prepared in this application uses plant-derived materials, does not use chemical cross-linking agents, and has no potential carcinogenic risk. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a photo of the appearance of a cellulose sponge.

[0019] Figure 2 The figure is a flow chart of the preparation method. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. Example 1

[0021] Add 1.00g each of hydroxyethyl cellulose and ethyl cellulose to 200ml of purified water, heat to 80°C, stir thoroughly to dissolve, then cool to 10°C. Add sodium carboxymethyl cellulose, heat to 80°C again, mix thoroughly, and cool to 50°C to defoam. Place the sample in a mold and freeze-dry. Follow the freezing procedure, cool to -30°C, then apply vacuum. Heat at 0.5°C / min to -15°C, then freeze-dry until dry. Heat to 20°C. Place in a vacuum oven and heat to 65°C for 2 hours to crosslink. After packaging, age for 2 hours. Example 2

[0022] Add 1.00g each of sodium carboxymethyl cellulose and methyl cellulose to 50ml of purified water, heat to 90°C, stir thoroughly to dissolve, then cool to 60°C. Add hydroxypropyl cellulose, heat again to 90°C, and mix thoroughly. After mixing, cool to 80°C to defoam. Place the sample into a mold and freeze-dry. Follow the freezing procedure, cool to -40°C, then apply vacuum. Raise the temperature at 0.1°C / min to -25°C, then freeze-dry until dry. Raise the temperature to 10°C. Place the sample in a vacuum oven and heat to 105°C for 8 hours to crosslink. After packaging, age the sample for 24 hours. Example 3

[0023] Add 1.00g of cellulose acetate butyrate to 50ml of purified water, heat to 90°C, stir thoroughly to dissolve, then cool to 60°C. Add cross-linked carboxymethyl cellulose, cool to 20°C, and mix thoroughly. After mixing, incubate at 20°C to defoam. Place the sample into a mold and freeze-dry. Follow the freezing procedure by cooling to -10°C, then applying vacuum. Raise the temperature at 0.3°C / min to -5°C, then freeze-dry until dry. Raise the temperature to 30°C. Place the sample in a vacuum oven and heat to 50°C for 24 hours to cross-link. After packaging, age the sample for 48 hours. Example 4

[0024] Add 1.00g of carboxymethyl cellulose to 20ml of purified water, heat to 70°C, stir thoroughly to dissolve, then cool to 50°C. Add 1.00g of hydroxyethyl cellulose, cool again to 40°C, and mix thoroughly. After mixing, incubate at 70°C to defoam. Place the sample in a mold and freeze-dry. Follow the freezing procedure, cool to -5°C, then apply vacuum. Raise the temperature at 0.01°C / min to -2°C, then freeze-dry until dry. Raise the temperature to 10°C. Place the sample in a vacuum oven and heat to 150°C for crosslinking for 24 hours. After packaging, age the sample for 120 hours.

[0025] Sponge performance test:

[0026] (1) Absorption rate: Take a piece of sponge, weigh it accurately, immerse it in physiological saline until it no longer absorbs, take it out and weigh it accurately to calculate the absorption rate. Repeat the test three times and take the average value.

[0027] (2) Compressive strength: Tested in accordance with GB / T 8813-2020, taking the compressive strength value when the sponge is 50% deformed.

[0028] (3) Degradation performance: Take a piece of sponge, immerse it in physiological saline, and perform degradation experiments at 37°C. Observe and record the changes in the sample's morphology.

[0029] Table 1: Sponge performance test results

[0030]

[0031] Finally, it should be noted that while the basic concepts have been described above, it should be apparent to those skilled in the art that the detailed disclosure is provided merely as an example and does not constitute a limitation of this specification. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and revisions to this specification. Such modifications, improvements, and revisions are suggested throughout this specification and remain within the spirit and scope of the exemplary embodiments of this specification. Furthermore, this specification uses specific terms to describe the embodiments of this specification. For example, terms such as "one embodiment," "an embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "one embodiment," "an embodiment," or "an alternative embodiment" two or more times in different places in this specification do not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of this specification may be appropriately combined. Furthermore, unless expressly provided in the claims, the order of the processing elements and sequences, the use of alphanumeric characters, or other designations described in this specification are not intended to limit the order of the processes and methods of this specification.

[0032] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A gelable cellulose composite sponge, characterized in that: The preparation method of the cellulose composite sponge comprises the following steps: (1) dissolution of the cellulose system: weigh a portion of the cellulose raw material, add it to hot water at 70-90°C, stir it mechanically until the cellulose is fully swollen, cool the solution to 10-60°C, add the remaining cellulose component, and mix it at 20-90°C until a cellulose solution with a solid content of 1-5% is formed; (2) defoaming: take the cellulose solution prepared in step (1) and keep it at 20-95°C for defoaming; (3) vacuum freeze drying: take the solution prepared in step (2) and pour it into a mold, and perform vacuum freeze drying to obtain a porous sponge; (4) Thermal crosslinking: the porous sponge obtained in step (3) is subjected to thermal crosslinking treatment in a vacuum oven at 50-150° C. for 2-24 hours; (5) Aging: after cooling, the sponge is packaged and aged for 2-120 hours to obtain a gelatinizable cellulose composite sponge; the cellulose system comprises methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium carboxymethyl cellulose and cellulose acetate butyrate; the cellulose composite sponge has a liquid absorption ratio of 10-40 times, a compressive strength of 2-12 kPa under 50% deformation conditions, can be gelled in physiological saline, becomes a gel in 24-48 hours, and is completely degraded in 96-120 hours.

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