阅读说明：本技术 一种温敏可逆水凝胶及其制备方法与应用 (Temperature-sensitive reversible hydrogel and preparation method and application thereof ) 是由 孙伟 弥胜利 梁木娇 董丽娜 郭钟伟 于 2021-08-03 设计创作，主要内容包括：本发明公开了一种温敏可逆水凝胶及其制备方法与应用,本发明公开的温敏可逆水凝胶的原料包括有纤维素类物质和HA-MA,纤维素类物质与HA-MA在碱性条件下通过加成反应制备得到温敏可逆水凝胶。本发明公开的温敏可逆水凝胶反应条件温和,挤出成型性较好,具有良好的生物相容性,在生物医药领域有较好的应用前景。(The invention discloses a temperature-sensitive reversible hydrogel and a preparation method and application thereof. The temperature-sensitive reversible hydrogel disclosed by the invention is mild in reaction condition, good in extrusion moldability, good in biocompatibility and good in application prospect in the field of biomedicine.)

1. The temperature-sensitive reversible hydrogel is characterized in that raw materials of the temperature-sensitive reversible hydrogel comprise a cellulose substance and HA-MA, and the temperature-sensitive reversible hydrogel is prepared by the addition reaction of the cellulose substance and the HA-MA under an alkaline condition.

2. The temperature-sensitive reversible hydrogel according to claim 1, wherein said cellulose-based substance comprises one or more of hemp, bamboo leaves or bagasse; preferably, the raw material of the temperature-sensitive reversible hydrogel also comprises a lithium hydroxide urea aqueous solution; preferably, the raw materials of the temperature-sensitive reversible hydrogel consist of cellulose substances, HA-MA and lithium hydroxide urea aqueous solution; preferably, the ratio of the cellulose substances, the HA-MA and the lithium hydroxide urea aqueous solution in parts by mass is: (0.5-30): (0.1-15): 50-127); preferably, the ratio of the cellulose substances, the HA-MA and the lithium hydroxide urea aqueous solution in parts by mass is: (0.5-30):(0.1-15):(50-99.7).

3. A temperature/uv dual-responsive hydrogel, wherein the raw materials of the temperature/uv dual-responsive hydrogel comprise the temperature-sensitive reversible hydrogel according to claim 1 or 2 and a photoinitiator.

4. The temperature/ultraviolet dual-responsive hydrogel according to claim 3, wherein the cellulose-based substance comprises one or more of hemp, bamboo leaves or bagasse; preferably, the raw material of the temperature/ultraviolet dual-responsive hydrogel also comprises a lithium hydroxide urea aqueous solution; preferably, the temperature/ultraviolet dual-responsive hydrogel raw material consists of cellulose substances, HA-MA, lithium hydroxide urea aqueous solution and a photoinitiator; preferably, the ratio of the cellulose-based substance, the HA-MA, the lithium hydroxide urea aqueous solution and the photoinitiator in parts by mass is: (0.5-30): (0.1-15): 50-127): 0.1-5); preferably, the ratio of the cellulose-based substance, the HA-MA, the lithium hydroxide urea aqueous solution and the photoinitiator in parts by mass is: (0.5-30):(0.1-15):(50-99.7):(0.1-5).

5. The preparation method of the temperature-sensitive reversible hydrogel is characterized by comprising the following steps:

and S1, mixing the HA-MA with the alkaline cellulose solution to obtain the temperature-sensitive reversible hydrogel.

6. The preparation method of the temperature-sensitive reversible hydrogel according to claim 5, further comprising the steps of preparing a cellulose solution: mixing cellulose substances and a lithium hydroxide urea aqueous solution to obtain a cellulose solution; preferably, the mixing mode of the cellulose substance and the lithium hydroxide urea aqueous solution comprises multiple times of freezing and thawing and stirring; preferably, the freezing and thawing and stirring comprise 4-5 times; preferably, the cellulose substance is mixed with the lithium hydroxide urea aqueous solution after being crushed; preferably, the temperature interval of the lithium hydroxide urea aqueous solution is T ≦ 0 ℃.

7. A preparation method of a temperature/ultraviolet dual-responsive hydrogel is characterized by comprising the following steps:

s1, mixing HA-MA with an alkaline cellulose solution to obtain temperature-sensitive reversible hydrogel;

s2, mixing a photoinitiator with the temperature-sensitive reversible hydrogel obtained in the step S1 to obtain the temperature/ultraviolet dual-responsiveness hydrogel.

8. The method for preparing the temperature/ultraviolet dual-responsive hydrogel according to claim 7, further comprising the steps of preparing a cellulose solution: mixing cellulose substances and a lithium hydroxide urea aqueous solution to obtain a cellulose solution; preferably, the mixing mode of the cellulose substance and the lithium hydroxide urea aqueous solution comprises multiple times of freezing and thawing and stirring; preferably, the freezing and thawing and stirring comprise 4-5 times; preferably, the cellulose substance is mixed with the lithium hydroxide urea aqueous solution after being crushed; preferably, the temperature interval of the lithium hydroxide urea aqueous solution is T ≦ 0 ℃.

9. The temperature-sensitive reversible hydrogel according to any one of claims 1 to 2, the temperature/ultraviolet dual-responsive hydrogel according to any one of claims 3 to 4, the temperature-sensitive reversible hydrogel prepared by the preparation method according to any one of claims 5 to 6, or the temperature/ultraviolet dual-responsive hydrogel prepared by the preparation method according to any one of claims 7 to 8, and the application thereof in the field of 3D printing or the field of biomedicine.

10. A biomedical product, comprising at least one of the temperature-sensitive reversible hydrogel according to any one of claims 1 to 2, the temperature/ultraviolet dual-responsive hydrogel according to any one of claims 3 to 4, the temperature-sensitive reversible hydrogel prepared by the preparation method according to any one of claims 5 to 6, or the temperature/ultraviolet dual-responsive hydrogel prepared by the preparation method according to any one of claims 7 to 8.

Technical Field

The invention relates to the technical field of new materials, in particular to a temperature-sensitive reversible hydrogel and a preparation method and application thereof.

Background

Hydrogels are a class of very hydrophilic three-dimensional network-structured gels that swell rapidly in water and in this swollen state can hold a large volume of water without dissolving. Because of their soft tissue properties and similarity to extracellular matrices, they have received much attention in the biomedical field. According to whether the hydrogel can respond to external stimulation or not, the hydrogel is divided into traditional hydrogel and intelligent hydrogel. The intelligent hydrogel can respond to the change of external conditions and is a bright point in hydrogel research. Biological 3D printing is a regenerative medical engineering technique that takes processing of active materials including cells, growth factors, biomaterials, etc. as the main content, with the goal of reconstructing human tissues and organs. Biological 3D printed hydrogel structures are widely used in tissue engineering and regenerative medicine by virtue of their strong biocompatibility. Nowadays, the preparation method of hydrogel is various, but it is mostly prepared by cross-linking reaction between raw materials, and the adopted cross-linking reaction mainly includes physical cross-linking and chemical cross-linking. Among them, the hydrogel prepared by physical crosslinking has poor extrusion moldability due to weak bonding force, while the chemical crosslinking method mostly adopts thermal initiation and other methods, and the reaction conditions are harsh.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the temperature-sensitive reversible hydrogel is prepared by addition reaction of cellulose substances and HA-MA, and HAs mild reaction conditions and good extrusion moldability.

The invention also provides a preparation method of the temperature-sensitive reversible hydrogel.

The invention also provides a temperature/ultraviolet dual-responsiveness hydrogel.

The invention also provides a preparation method of the temperature/ultraviolet dual-responsiveness hydrogel.

The invention also provides application of the temperature-sensitive reversible hydrogel and the temperature/ultraviolet dual-responsiveness hydrogel.

The invention also provides a biomedical product.

The invention provides a temperature-sensitive reversible hydrogel, which comprises the following raw materials: the temperature-sensitive reversible hydrogel is prepared from cellulose substances and HA-MA through addition reaction under an alkaline condition.

It should be noted that: HA-MA is methacrylated hyaluronic acid (HA-MA) obtained by esterification reaction of sodium hyaluronate and Methacrylic Anhydride (MA).

HA-MA is prepared as shown in equation (1):

the temperature-sensitive reversible hydrogel provided by the embodiment of the invention at least has the following beneficial effects:

cellulose solution is prepared from cellulose substances, the cellulose solution is mixed with HA-MA, vinyl in the HA-MA can perform addition reaction with cellulose under alkaline conditions to form ether bonds, specifically, hydroxyl of the cellulose and double bonds of the HA-MA perform addition reaction to form ether bonds, so that the temperature-sensitive reversible hydrogel is obtained; the preparation method is simple, the whole preparation process has no complex steps and harsh conditions, and the preparation method is simple, easy and mild;

the raw materials comprise cellulose substances, and the prepared temperature-sensitive reversible hydrogel has excellent mechanical properties, excellent rheological properties and good extrusion moldability and can be used as a 3D printing material;

the hydrogel prepared by the invention can respond to the change of the external temperature, the temperature-sensitive characteristic is reversible, the hydrogel can be changed into a solidified state from a flowing state at a specific temperature, and once the temperature returns to the original condition again, the hydrogel can return to the flowing state again. The solidification state facilitates the molding of the printed structure, and the re-restoration of the flow state facilitates the subsequent biomedical applications, such as drug release and delivery acceleration;

the material cellulose and hyaluronic acid used by the hydrogel prepared by the invention have good biocompatibility and have good application prospect in the field of biomedicine.

In some embodiments of the invention, the cellulosic material comprises one or more of hemp, bamboo leaves, or bagasse.

Through the implementation mode, the hemp threads, the bamboo leaves and the bagasse are all rich in cellulose, have wide and easily-obtained sources, are low in cost, and are energy-saving and environment-friendly. Meanwhile, the dissolved cellulose solution is a viscous solution, the mechanical property, particularly the rigidity, of the cellulose solution is improved compared with other cellulose hydrogels, and the viscous solution has excellent rheological property, so that the hydrogel has good extrusion formability and can be used as a 3D printing material.

In some preferred embodiments of the present invention, the cellulose-based material is subjected to a pulverization treatment.

In some embodiments of the invention, HA-MA is methacrylated hyaluronic acid (HA-MA) obtained by esterification of sodium hyaluronate and Methacrylic Anhydride (MA).

In some embodiments of the present invention, the raw material of the temperature-sensitive reversible hydrogel further comprises an aqueous solution of lithium hydroxide and urea.

The lithium hydroxide urea aqueous solution provides an alkaline environment for a reaction system, cellulose substances are dissolved in the lithium hydroxide urea aqueous solution, the dissolved cellulose solution is a viscous solution, the mechanical property, particularly the rigidity, is improved compared with other cellulose hydrogels, and the viscous solution has excellent rheological property, so that the prepared hydrogel has good extrusion moldability and can be used as a 3D printing material;

the dissolution process of cellulose substances is an inclusion process, and under low temperature conditions, sodium hydroxide hydrate is bonded to cellulose chains by forming hydrogen bonds, while urea hydrate can self-assemble on the surface of sodium hydroxide hydrogen bonds to form inclusion compounds.

In some preferred embodiments of the invention, the cellulose solution is a viscous cellulose solution.

In some preferred embodiments of the invention, the ratio of parts by mass of the HA-MA to the aqueous lithium hydroxide solution is: (0.1-15):(50-127).

In some preferred embodiments of the invention, the ratio of parts by mass of the HA-MA to the aqueous lithium hydroxide solution is: (0.1-15):127.

In some preferred embodiments of the invention, the ratio of parts by mass of the HA-MA to the aqueous lithium hydroxide solution is: (0.1-15):(50-99.7).

In some embodiments of the invention, the ratio of parts by mass of the cellulosic material to the HA-MA is: (0.5-30):(0.1-15).

In some embodiments of the present invention, the raw materials of the temperature-sensitive reversible hydrogel are composed of a cellulose-based material, HA-MA and an aqueous solution of lithium hydroxide and urea.

Through the embodiment, the raw materials of the temperature-sensitive reversible hydrogel only consist of the cellulose substances, the HA-MA and the lithium hydroxide urea aqueous solution, the lithium hydroxide urea aqueous solution not only dissolves the cellulose substances, but also provides an alkaline environment, the cellulose substances and the HA-MA are subjected to addition reaction under an alkaline condition to form ether bonds, specifically, hydroxyl groups of cellulose and double bonds of the HA-MA are subjected to addition reaction to form ether bonds, so that the temperature-sensitive reversible hydrogel is obtained, the raw materials are simple in components, other components (such as a cross-linking agent) do not need to be added additionally, and the cost is reduced.

In some preferred embodiments of the present invention, the ratio of parts by mass of the cellulosic material, the HA-MA, and the aqueous lithium hydroxide solution is: (0.5-30):(0.1-15):(50-127).

In some more preferred embodiments of the present invention, the ratio of parts by mass of the cellulosic material, the HA-MA, and the aqueous lithium hydroxide solution is: (0.5-30):(0.1-15):(50-99.7).

In some embodiments of the present invention, the temperature-sensitive reversible hydrogel has a curing temperature range of 10 ℃ or more.

In some embodiments of the present invention, the temperature-sensitive reversible hydrogel has a curing temperature range of 10-40 ℃.

In some preferred embodiments of the present invention, the temperature-sensitive reversible hydrogel returns to a fluid state at a temperature below the curing temperature.

In some embodiments of the invention, a method for preparing an aqueous solution of lithium hydroxide urea comprises: and mixing lithium hydroxide, urea and water, and dissolving to obtain the lithium hydroxide urea aqueous solution.

In some preferred embodiments of the invention, the ratio of parts by mass of lithium hydroxide, urea and water comprises 7:20: 100.

In some more preferred embodiments of the present invention, the mass-to-volume ratio of cellulosic material to water is (0.5-30): 100.

In some embodiments of the invention, a method of preparing HA-MA comprises: adding MA into HA water solution, adjusting pH to neutral, dialyzing, freezing, and drying to obtain HA-MA.

Wherein HA is hyaluronic acid; MA is Methacrylic Anhydride (Methacrylic Anhydride).

In a second aspect of the present invention, a temperature/ultraviolet dual-responsive hydrogel is provided, and raw materials of the temperature/ultraviolet dual-responsive hydrogel include the above temperature-sensitive reversible hydrogel and a photoinitiator.

The temperature/ultraviolet dual-responsive hydrogel provided by the embodiment of the invention has at least the following beneficial effects:

according to the invention, cellulose solution is prepared from cellulose substances, and the cellulose solution and HA-MA are mixed, because HA-MA contains vinyl, the vinyl in HA-MA can perform addition reaction with cellulose under an alkaline condition to form ether bonds, specifically, hydroxyl of cellulose and double bonds of HA-MA perform addition reaction to form ether bonds, so that the temperature-sensitive reversible hydrogel is obtained; after the photoinitiator is added, the obtained temperature/ultraviolet dual-responsive hydrogel HAs ultraviolet responsiveness and specific temperature-sensitive reversibility before ultraviolet irradiation, wherein HA-MA is used as natural polysaccharide with good biocompatibility and can be crosslinked with ultraviolet light to play a role in curing a gel network. The specific process can be as follows: HA-MA and cellulose solution are mixed to obtain temperature-sensitive reversible hydrogel, a photoinitiator is added to obtain temperature/ultraviolet dual-responsiveness hydrogel, 3D printing is carried out, the printing structure is cured by temperature rise, and secondary curing can be realized by ultraviolet irradiation.

The preparation method is simple, the whole preparation process has no complex steps and harsh conditions, and the preparation method is simple, easy and mild;

the raw materials comprise cellulose substances, and the prepared temperature/ultraviolet dual-responsiveness hydrogel has excellent mechanical properties, excellent rheological properties and good extrusion moldability, and can be used as a 3D printing material;

the hydrogel prepared by the invention has temperature/ultraviolet dual response performance, can respond to the change of external temperature, has reversible temperature-sensitive characteristic, can change the hydrogel from a flowing state to a solidified state at a specific temperature, and can return to the flowing state once the temperature returns to the original condition again. The solidification state facilitates the molding of the printed structure, and the re-restoration of the flow state facilitates the subsequent biomedical applications, such as drug release and delivery acceleration; meanwhile, the hydrogel can be cured by ultraviolet irradiation without being influenced by other conditions such as oxidation and the like;

the material cellulose and hyaluronic acid used by the hydrogel prepared by the invention have good biocompatibility and have good application prospect in the field of biomedicine.

In some embodiments of the invention, the cellulosic material comprises one or more of hemp, bamboo leaves, or bagasse.

Through the implementation mode, the hemp threads, the bamboo leaves and the bagasse are all rich in cellulose, have wide and easily-obtained sources, are low in cost, and are energy-saving and environment-friendly. Through the implementation mode, the hemp threads, the bamboo leaves and the bagasse are all rich in cellulose, have wide and easily-obtained sources, are low in cost, and are energy-saving and environment-friendly. Meanwhile, the dissolved cellulose solution is a viscous solution, the mechanical property, particularly the rigidity, of the cellulose solution is improved compared with other cellulose hydrogels, and the viscous solution has excellent rheological property, so that the hydrogel has good extrusion formability and can be used as a 3D printing material.

In some preferred embodiments of the present invention, the cellulose-based material is subjected to a pulverization treatment.

In some embodiments of the invention, HA-MA is methacrylated hyaluronic acid (HA-MA) obtained by esterification of sodium hyaluronate and Methacrylic Anhydride (MA).

In some embodiments of the invention, the photoinitiator comprises 2959 photoinitiator.

In some embodiments of the present invention, the raw material of the temperature/uv dual-responsive hydrogel further comprises an aqueous solution of lithium hydroxide and urea.

The lithium hydroxide urea aqueous solution provides an alkaline environment for a reaction system, cellulose substances are dissolved in the lithium hydroxide urea aqueous solution, the dissolved cellulose solution is a viscous solution, the mechanical property, particularly the rigidity, is improved compared with other cellulose hydrogels, and the viscous solution has excellent rheological property, so that the prepared hydrogel has good extrusion moldability and can be used as a 3D printing material;

the dissolution process of cellulose substances is an inclusion process, and under low temperature conditions, sodium hydroxide hydrate is bonded to cellulose chains by forming hydrogen bonds, while urea hydrate can self-assemble on the surface of sodium hydroxide hydrogen bonds to form inclusion compounds.

In some preferred embodiments of the invention, the ratio of parts by mass of the HA-MA to the aqueous lithium hydroxide solution is: (0.1-15):(50-127).

In some preferred embodiments of the invention, the ratio of parts by mass of the HA-MA to the aqueous lithium hydroxide solution is: (0.1-15):(50-99.7).

In some preferred embodiments of the invention, the cellulose solution is a viscous cellulose solution.

In some embodiments of the invention, the ratio of parts by mass of the cellulosic material to the HA-MA is: (0.5-30):(0.1-15).

In some embodiments of the invention, the ratio of parts by mass of the HA-MA to the photoinitiator is: (0.1-15):(0.12-5.92).

In some embodiments of the invention, the ratio of parts by mass of the HA-MA to the photoinitiator is: (0.1-15):(0.1-5).

In some embodiments of the present invention, the temperature/uv dual-responsive hydrogel material is composed of a cellulosic material, HA-MA, an aqueous solution of lithium hydroxide and urea, and a photoinitiator.

According to the embodiment, the temperature/ultraviolet dual-responsive hydrogel is prepared from the raw materials only consisting of the cellulose substance, the HA-MA, the lithium hydroxide urea aqueous solution and the photoinitiator, wherein the lithium hydroxide urea aqueous solution not only dissolves the cellulose substance, but also provides an alkaline environment, the cellulose substance and the HA-MA are subjected to addition reaction under an alkaline condition to form ether bonds, specifically, hydroxyl groups of cellulose and double bonds of the HA-MA are subjected to addition reaction to form ether bonds, so that the temperature-sensitive reversible hydrogel is obtained, and then the photoinitiator is added to prepare the temperature/ultraviolet dual-responsive hydrogel.

In some preferred embodiments of the present invention, the ratio of the parts by mass of the cellulosic material, the HA-MA, the aqueous lithium hydroxide solution, and the photoinitiator is: (0.5-30):(0.1-15):(50-127):(0.12-5.92).

In some preferred embodiments of the present invention, the ratio of the parts by mass of the cellulosic material, the HA-MA, the aqueous lithium hydroxide solution, and the photoinitiator is: (0.5-30):(0.1-15):(50-99.7):(0.12-5.92).

In some preferred embodiments of the present invention, the ratio of the parts by mass of the cellulosic material, the HA-MA, the aqueous lithium hydroxide solution, and the photoinitiator is: (0.5-30):(0.1-15):(50-99.7):(0.1-5).

In some embodiments of the present invention, the temperature/uv dual-responsive hydrogel has a curing temperature of 10 ℃ or higher.

In some embodiments of the invention, the curing temperature of the temperature/uv dual responsive hydrogel comprises 10-40 ℃.

In some preferred embodiments of the present invention, the temperature/uv dual responsive hydrogel recovers a fluid state at a temperature below the curing temperature without uv exposure.

In some embodiments of the invention, a method for preparing an aqueous solution of lithium hydroxide urea comprises: and mixing lithium hydroxide, urea and water, and dissolving to obtain the lithium hydroxide urea aqueous solution.

In some more preferred embodiments of the present invention, the volume ratio of the photoinitiator to water is (0.1-5): 100.

In some embodiments of the invention, a method of preparing HA-MA comprises: adding MA into HA water solution, adjusting pH to neutral, dialyzing, freezing, and drying to obtain HA-MA.

Wherein HA is hyaluronic acid; MA is Methacrylic Anhydride (Methacrylic Anhydride).

In some embodiments of the present invention, the UV irradiation time interval is 0.5-10min during UV curing.

The third aspect of the invention provides a preparation method of a temperature-sensitive reversible hydrogel, which comprises the following steps:

and S1, mixing the HA-MA with the alkaline cellulose solution to obtain the temperature-sensitive reversible hydrogel.

It should be noted that: HA-MA is methacrylated hyaluronic acid (HA-MA) obtained by esterification reaction of sodium hyaluronate and Methacrylic Anhydride (MA).

The preparation method of the temperature-sensitive reversible hydrogel provided by the embodiment of the invention at least has the following beneficial effects:

according to the invention, cellulose solution is prepared from cellulose substances, and the cellulose solution and HA-MA are mixed, because HA-MA contains vinyl, the vinyl in HA-MA can perform addition reaction with cellulose under an alkaline condition to form ether bonds, specifically, hydroxyl of cellulose and double bonds of HA-MA perform addition reaction to form ether bonds, so that the temperature-sensitive reversible hydrogel is obtained; the preparation method is simple, the whole preparation process has no complex steps and harsh conditions, and the preparation method is simple, easy and mild;

the raw materials comprise cellulose substances, and the prepared temperature-sensitive reversible hydrogel has excellent mechanical properties, excellent rheological properties and good extrusion moldability and can be used as a 3D printing material;

the hydrogel prepared by the invention can respond to the change of the external temperature, the temperature-sensitive characteristic is reversible, the hydrogel can be changed into a solidified state from a flowing state at a specific temperature, and once the temperature returns to the original condition again, the hydrogel can return to the flowing state again. The solidification state facilitates the molding of the printed structure, and the re-restoration of the flow state facilitates the subsequent biomedical applications, such as drug release and delivery acceleration;

the material cellulose and hyaluronic acid used by the hydrogel prepared by the invention have good biocompatibility and have good application prospect in the field of biomedicine.

In some embodiments of the invention, the preparation of the cellulose solution is further comprised: the cellulose substance and the lithium hydroxide urea aqueous solution are mixed to obtain a cellulose solution.

The lithium hydroxide urea aqueous solution provides an alkaline environment for a reaction system, cellulose substances are dissolved in the lithium hydroxide urea aqueous solution, the dissolved cellulose solution is a viscous solution, the mechanical property, particularly the rigidity, is improved compared with other cellulose hydrogels, and the viscous solution has excellent rheological property, so that the prepared hydrogel has good extrusion moldability and can be used as a 3D printing material;

the dissolution process of cellulose substances is an inclusion process, and under low temperature conditions, sodium hydroxide hydrate is bonded to cellulose chains by forming hydrogen bonds, while urea hydrate can self-assemble on the surface of sodium hydroxide hydrogen bonds to form inclusion compounds.

In some preferred embodiments of the present invention, the mixing of the cellulose-based substance and the aqueous lithium hydroxide solution comprises multiple freezing and thawing and stirring.

Multiple times of freeze thawing can obviously reduce the strong hydrogen bond interaction in and among cellulose molecules, destroy the compact crystal structure of cellulose, disorder the molecular structure of cellulose and better dissolve cellulose substances.

In the present invention, the multiple freezing and thawing and stirring means: freezing the mixed system to a certain temperature I (which can be-10 ℃), and mechanically stirring; once the system has risen to a certain temperature II, which may be 0 deg.C, the above operations are repeated. Wherein the temperature I is lower than the temperature II.

In some more preferred embodiments of the present invention, the freezing and thawing and the agitation comprise 4 to 5 times.

In some preferred embodiments of the present invention, the cellulose-based material is pulverized and then mixed with the aqueous solution of lithium hydroxide and urea.

In some more preferred embodiments of the invention, the temperature interval of the aqueous lithium hydroxide urea solution is T.ltoreq.0 ℃.

The dissolution process of cellulose substances is an inclusion process, and under low temperature conditions, sodium hydroxide hydrate is bonded to cellulose chains by forming hydrogen bonds, while urea hydrate can self-assemble on the surface of sodium hydroxide hydrogen bonds to form inclusion compounds.

In some embodiments of the invention, in step S1: HA-MA is mixed with a low temperature cellulose solution.

In some preferred embodiments of the present invention, in step S1: the temperature range of the cellulose solution is less than or equal to 0 ℃.

In some embodiments of the invention, in step S1: the HA-MA concentration is 0.1-15% (w/v).

In some embodiments of the invention, in step S1: the mass-volume ratio of the HA-MA to the cellulose solution is as follows: (0.1-15):100.

The fourth aspect of the invention provides a preparation method of a temperature/ultraviolet dual-responsiveness hydrogel, which comprises the following steps:

s1, mixing HA-MA with an alkaline cellulose solution to obtain temperature-sensitive reversible hydrogel;

s2, mixing a photoinitiator with the temperature-sensitive reversible hydrogel obtained in the step S1 to obtain the temperature/ultraviolet dual-responsiveness hydrogel.

The preparation method of the temperature/ultraviolet dual-responsiveness hydrogel provided by the embodiment of the invention has at least the following beneficial effects:

according to the invention, cellulose solution is prepared from cellulose substances, and the cellulose solution and HA-MA are mixed, because HA-MA contains vinyl, the vinyl in HA-MA can perform addition reaction with cellulose under an alkaline condition to form ether bonds, specifically, hydroxyl of cellulose and double bonds of HA-MA perform addition reaction to form ether bonds, so that the temperature-sensitive reversible hydrogel is obtained; after the photoinitiator is added, the obtained temperature/ultraviolet dual-responsive hydrogel HAs ultraviolet responsiveness and specific temperature-sensitive reversibility before ultraviolet irradiation, wherein HA-MA is used as natural polysaccharide with good biocompatibility and can be crosslinked with ultraviolet light to play a role in curing a gel network. The specific process can be as follows: HA-MA and cellulose solution are mixed to obtain temperature-sensitive reversible hydrogel, a photoinitiator is added to obtain temperature/ultraviolet dual-responsiveness hydrogel, 3D printing is carried out, the printing structure is cured by temperature rise, and secondary curing can be realized by ultraviolet irradiation.

The preparation method is simple, the whole preparation process has no complex steps and harsh conditions, and the preparation method is simple, easy and mild;

the raw materials comprise cellulose substances, and the prepared temperature/ultraviolet dual-responsiveness hydrogel has excellent mechanical properties, excellent rheological properties and good extrusion moldability, and can be used as a 3D printing material;

the hydrogel prepared by the invention has temperature/ultraviolet dual response performance, can respond to the change of external temperature, has reversible temperature-sensitive characteristic, can change the hydrogel from a flowing state to a solidified state at a specific temperature, and can return to the flowing state once the temperature returns to the original condition again. The solidification state facilitates the molding of the printed structure, and the re-restoration of the flow state facilitates the subsequent biomedical applications, such as drug release and delivery acceleration; meanwhile, the hydrogel can be cured by ultraviolet irradiation without being influenced by other conditions such as oxidation and the like;

the material cellulose and hyaluronic acid used by the hydrogel prepared by the invention have good biocompatibility and have good application prospect in the field of biomedicine.

In some embodiments of the invention, the preparation of the cellulose solution is further comprised: the cellulose substance and the lithium hydroxide urea aqueous solution are mixed to obtain a cellulose solution.

The lithium hydroxide urea aqueous solution provides an alkaline environment for a reaction system, cellulose substances are dissolved in the lithium hydroxide urea aqueous solution, the dissolved cellulose solution is a viscous solution, the mechanical property, particularly the rigidity, is improved compared with other cellulose hydrogels, and the viscous solution has excellent rheological property, so that the prepared hydrogel has good extrusion moldability and can be used as a 3D printing material;

the dissolution process of cellulose substances is an inclusion process, and under low temperature conditions, sodium hydroxide hydrate is bonded to cellulose chains by forming hydrogen bonds, while urea hydrate can self-assemble on the surface of sodium hydroxide hydrogen bonds to form inclusion compounds.

In some preferred embodiments of the present invention, the mixing of the cellulose-based substance and the aqueous lithium hydroxide solution comprises multiple freezing and thawing and stirring.

Multiple times of freeze thawing can obviously reduce the strong hydrogen bond interaction in and among cellulose molecules, destroy the compact crystal structure of cellulose, disorder the molecular structure of cellulose and better dissolve cellulose substances.

In some more preferred embodiments of the present invention, the freezing and thawing and the agitation comprise 4 to 5 times.

In some preferred embodiments of the present invention, the cellulose-based material is pulverized and then mixed with the aqueous solution of lithium hydroxide and urea.

In some more preferred embodiments of the invention, the temperature interval of the aqueous lithium hydroxide urea solution is T.ltoreq.0 ℃.

The dissolution process of cellulose substances is an inclusion process, and under low temperature conditions, sodium hydroxide hydrate is bonded to cellulose chains by forming hydrogen bonds, while urea hydrate can self-assemble on the surface of sodium hydroxide hydrogen bonds to form inclusion compounds.

In some embodiments of the invention, in step S1: HA-MA is mixed with a low temperature cellulose solution.

In some preferred embodiments of the present invention, in step S1: the temperature range of the cellulose solution is less than or equal to 0 ℃.

In some embodiments of the invention, in step S1: the HA-MA concentration is 0.1-15% (w/v).

In some embodiments of the invention, in step S1: the mass-volume ratio of the HA-MA to the cellulose solution is as follows: (0.1-15):100.

In some embodiments of the invention, in step S2: the concentration of the photoinitiator is 0.1-5% (w/v).

In some preferred embodiments of the present invention, in step S2: the concentration of the photoinitiator was 0.5% (w/v).

In a fifth aspect of the present invention, applications of the temperature-sensitive reversible hydrogel and the temperature/ultraviolet dual-responsive hydrogel in the 3D printing field or the biomedical field are provided.

In a sixth aspect of the present invention, there is also provided a biomedical article comprising at least one of the above temperature-sensitive reversible hydrogel or the above temperature/ultraviolet dual-responsive hydrogel.

Drawings

The invention is further described with reference to the following figures and examples, in which:

FIG. 1 is a graph showing the results of an experiment for thermo-sensitive reversibility of a hydrogel in an example of the present invention;

FIG. 2 is a graph of experimental hydrogel biocompatibility data (CCK8 cytotoxicity test) in examples of the present invention;

FIG. 3 is a graph showing the results of an experiment for the extrusion moldability of a hydrogel in an example of the present invention;

fig. 4 is a digital photograph of a 3D printed grid structure of a temperature/uv responsive hydrogel in an embodiment of the invention.

Detailed Description

The concept and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments to fully understand the objects, features and effects of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and those skilled in the art can obtain other embodiments without inventive effort based on the embodiments of the present invention, and all embodiments are within the protection scope of the present invention.

Details of the chemical reagents used in the examples of the present invention are as follows:

HA：Lifecore Biomedical(Chaska,MN,USA)；

MA：Sigma-Aldrich(St.Louis,MO,USA)；

2959 photoinitiator: Sigma-Aldrich (st. louis, MO, USA);

preparation of HA-MA: after dissolving 1g of HA (hyaluronic acid) in 100mL of deionized water and stirring thoroughly for 3 hours at room temperature, 2mL of MA (methacrylic anhydride) was added dropwise with stirring, stirring was continued and the pH was adjusted to neutral by 1mol/L NaOH (pH 8). Transferring to a dialysis bag for dialysis, and freeze-drying to obtain HA-MA.

According to the experimental requirements, a proper amount of HA-MA can be prepared according to the preparation method.

Preparation of lithium hydroxide urea aqueous solution: 7g of lithium hydroxide and 20g of urea were added to 100mL of water, and sufficiently stirred until completely dissolved, to obtain a uniform lithium hydroxide urea aqueous solution.

Multiple portions of aqueous lithium hydroxide solution were prepared in parallel.

It should be noted that, unless otherwise specified, the freeze-thaw agitation in the following examples is specifically: freezing the mixed system (lithium hydroxide urea aqueous solution and hemp) to-10 ℃, and mechanically stirring; once the system had risen to 0 deg.C, the above operation was repeated.

Example 1

In this example, a temperature/ultraviolet dual-responsive hydrogel is prepared, and the specific process is as follows:

and (I) adding 0.5g of dry and crushed hemp silk powder into one part of the prepared lithium hydroxide urea aqueous solution, fully and mechanically stirring, and repeatedly freezing and thawing and stirring for 5 times until the hemp silk powder is completely dissolved to obtain a viscous cellulose solution.

And (II) adding 0.1g of HA-MA into the cellulose solution obtained in the step (I), and fully stirring at the temperature of 0 ℃ under an ice bath condition to obtain the temperature-sensitive reversible hydrogel.

And (III) adding 0.1mL of 2959 photoinitiator into the temperature-sensitive reversible hydrogel system obtained in the step (II) and uniformly mixing to obtain the temperature/ultraviolet dual-responsiveness hydrogel for 3D printing.

(IV), a shaping process: 3D printing the temperature/ultraviolet dual-response hydrogel obtained in the step (III) to obtain a grid structure, wherein the grid structure can be cured by heating to 25 ℃, and then is subjected to ultraviolet light (wavelength of 275nm and intensity of 15 mW/cm)²) And (5) irradiating for 0.5min to realize secondary curing (as shown in figure 4), namely finishing the shaping process of the printing structure.

The result of testing the temperature-sensitive property of the temperature-sensitive reversible hydrogel obtained in the step (II) is shown in figure 1, the result of testing the biocompatibility of the hydrogel is shown in figure 2, and the result of testing the extrusion moldability of the hydrogel is shown in figure 3.

The structure of the temperature/uv dual-responsive hydrogel after the secondary curing in step (iv) was tested, and the results are shown in fig. 4.

And (3) testing the temperature-sensitive characteristic, the biocompatibility and the extrusion moldability of the temperature/ultraviolet dual-responsive hydrogel obtained in the step (III), wherein the test result is equivalent to that of the temperature-sensitive reversible hydrogel obtained in the step (II).

Example 2

In this example, a temperature/ultraviolet dual-responsive hydrogel is prepared, and the specific process is as follows:

and (I) adding 0.5g of crushed and dried hemp into one part of the prepared lithium hydroxide urea aqueous solution, and repeatedly and fully mechanically stirring for 5 times until the hemp is completely dissolved to obtain a viscous cellulose solution.

And (II) adding 7.5g of HA-MA into the cellulose solution obtained in the step (I), and fully stirring at the temperature of 0 ℃ under an ice bath condition to obtain the temperature-sensitive reversible hydrogel.

And (III) adding 2.5mL of 2959 photoinitiator into the temperature-sensitive reversible hydrogel system obtained in the step (II) and uniformly mixing to obtain the temperature/ultraviolet dual-responsiveness hydrogel for 3D printing.

(IV), a shaping process: and (3) 3D printing the temperature/ultraviolet dual-responsiveness hydrogel obtained in the step (III) to obtain a grid structure, and curing the grid structure by heating to 10 ℃. Subjecting to ultraviolet light (wavelength 275nm, intensity 15 mW/cm)²) And irradiating for 5min to realize secondary curing, thus finishing the shaping process of the printing structure.

The experimental results are comparable to example 1.

Example 3

In this example, a temperature/ultraviolet dual-responsive hydrogel is prepared, and the specific process is as follows:

and (I) adding 0.5g of crushed and dried hemp into one part of the prepared lithium hydroxide urea aqueous solution, and repeatedly and fully mechanically stirring for 5 times until the hemp is completely dissolved to obtain a viscous cellulose solution.

And (II) adding 15g of HA-MA into the cellulose solution obtained in the step (I), and fully stirring at the temperature of 0 ℃ under an ice bath condition to obtain the temperature-sensitive reversible hydrogel.

And (III) adding 5mL of 2959 photoinitiator into the temperature-sensitive reversible hydrogel system obtained in the step (II) and uniformly mixing to obtain the temperature/ultraviolet dual-responsiveness hydrogel for 3D printing.

(IV), a shaping process: and (3) 3D printing the temperature/ultraviolet dual-responsiveness hydrogel obtained in the step (III) to obtain a grid structure, and curing the grid structure by heating to 40 ℃. Subjecting to ultraviolet light (wavelength 275nm, intensity 15 mW/cm)²) And irradiating for 10min to realize secondary curing, namely finishing the shaping process of the printing structure.

The experimental results are comparable to example 1.

Example 4

In this example, a temperature/ultraviolet dual-responsive hydrogel is prepared, and the specific process is as follows:

and (I) adding 15g of dry and crushed hemp silk powder into one part of the prepared lithium hydroxide urea aqueous solution, fully and mechanically stirring, and repeatedly freezing, thawing and stirring for 5 times until the hemp silk powder is completely dissolved to obtain a viscous cellulose solution.

And (II) adding 0.1g of HA-MA into the cellulose solution obtained in the step (I), and fully stirring at the temperature of 0 ℃ under an ice bath condition to obtain the temperature-sensitive reversible hydrogel.

And (III) adding 2.5mL of 2959 photoinitiator into the temperature-sensitive reversible hydrogel system obtained in the step (II) and uniformly mixing to obtain the temperature/ultraviolet dual-responsiveness hydrogel for 3D printing.

(IV), a shaping process: and (3) 3D printing the temperature/ultraviolet dual-responsiveness hydrogel obtained in the step (III) to obtain a grid structure, and curing the grid structure by heating to 10 ℃. Subjecting to ultraviolet light (wavelength 275nm, intensity 15 mW/cm)²) And irradiating for 0.5min to realize secondary curing, namely finishing the shaping process of the printing structure.

The experimental results are comparable to example 1.

Example 5

In this example, a temperature/ultraviolet dual-responsive hydrogel is prepared, and the specific process is as follows:

and (I) adding 15g of dry and crushed hemp silk powder into one part of the prepared lithium hydroxide urea aqueous solution, fully and mechanically stirring, and repeatedly freezing, thawing and stirring for 5 times until the hemp silk powder is completely dissolved to obtain a viscous cellulose solution.

And (II) adding 15g of HA-MA into the cellulose solution obtained in the step (I), and fully stirring at the temperature of 0 ℃ under an ice bath condition to obtain the temperature-sensitive reversible hydrogel.

And (III) adding 5mL of 2959 photoinitiator into the temperature-sensitive reversible hydrogel system obtained in the step (II) and uniformly mixing to obtain the temperature/ultraviolet dual-responsiveness hydrogel for 3D printing.

(IV), a shaping process: and (3) 3D printing the temperature/ultraviolet dual-responsiveness hydrogel obtained in the step (III) to obtain a grid structure, and heating the grid structure to 25 ℃ to realize curing. Subjecting to ultraviolet light (wavelength 275nm, intensity 15 mW/cm)²) And irradiating for 5min to realize secondary curing, thus finishing the shaping process of the printing structure.

The experimental results are comparable to example 1.

Example 6

In this example, a temperature/ultraviolet dual-responsive hydrogel is prepared, and the specific process is as follows:

and (I) adding 15g of dry and crushed hemp silk powder into one part of the prepared lithium hydroxide urea aqueous solution, fully and mechanically stirring, and repeatedly freezing, thawing and stirring for 5 times until the hemp silk powder is completely dissolved to obtain a viscous cellulose solution.

And (II) adding 7.5g of HA-MA into the cellulose solution obtained in the step (I), and fully stirring at the temperature of 0 ℃ under an ice bath condition to obtain the temperature-sensitive reversible hydrogel.

And (III) adding 5mL of 2959 photoinitiator into the temperature-sensitive reversible hydrogel system obtained in the step (II) and uniformly mixing to obtain the temperature/ultraviolet dual-responsiveness hydrogel for 3D printing.

(IV), a shaping process: and (3) 3D printing the temperature/ultraviolet dual-responsiveness hydrogel obtained in the step (III) to obtain a grid structure, and curing the grid structure by heating to 40 ℃. Subjecting to ultraviolet light (wavelength 275nm, intensity 15 mW/cm)²) And irradiating for 5min to realize secondary curing, thus finishing the shaping process of the printing structure.

The experimental results are comparable to example 1.

Example 7

In this example, a temperature/ultraviolet dual-responsive hydrogel is prepared, and the specific process is as follows:

and (I) adding 30g of dry and crushed hemp silk powder into one part of the prepared lithium hydroxide urea aqueous solution, fully and mechanically stirring, and repeatedly freezing, thawing and stirring for 5 times until the hemp silk powder is completely dissolved to obtain a viscous cellulose solution.

And (II) adding 15g of HA-MA into the cellulose solution obtained in the step (I), and fully stirring at the temperature of 0 ℃ under an ice bath condition to obtain the temperature-sensitive reversible hydrogel.

And (III) adding 5mL of 2959 photoinitiator into the temperature-sensitive reversible hydrogel system obtained in the step (II) and uniformly mixing to obtain the temperature/ultraviolet dual-responsiveness hydrogel for 3D printing.

(IV), a shaping process: will be described in detailAnd (III) carrying out 3D printing on the obtained temperature/ultraviolet dual-responsiveness hydrogel to obtain a grid structure, wherein the grid structure can be cured by heating to 10 ℃. Subjecting to ultraviolet light (wavelength 275nm, intensity 15 mW/cm)²) And irradiating for 10min to realize secondary curing, namely finishing the shaping process of the printing structure.

The experimental results are comparable to example 1.

Example 8

In this example, a temperature/ultraviolet dual-responsive hydrogel is prepared, and the specific process is as follows:

and (I) adding 30g of dry and crushed hemp silk powder into one part of the prepared lithium hydroxide urea aqueous solution, fully and mechanically stirring, and repeatedly freezing, thawing and stirring for 5 times until the hemp silk powder is completely dissolved to obtain a viscous cellulose solution.

And (II) adding 7.5g of HA-MA into the cellulose solution obtained in the step (I), and fully stirring at the temperature of 0 ℃ under an ice bath condition to obtain the temperature-sensitive reversible hydrogel.

And (III) adding 2.5mL of 2959 photoinitiator into the temperature-sensitive reversible hydrogel system obtained in the step (II) and uniformly mixing to obtain the temperature/ultraviolet dual-responsiveness hydrogel for 3D printing.

(IV), a shaping process: and (3) 3D printing the temperature/ultraviolet dual-responsiveness hydrogel obtained in the step (III) to obtain a grid structure, and curing the grid structure by heating to 40 ℃. Subjecting to ultraviolet light (wavelength 275nm, intensity 15 mW/cm)²) And irradiating for 5min to realize secondary curing, thus finishing the shaping process of the printing structure.

The experimental results are comparable to example 1.

Example 9

In this example, a temperature/ultraviolet dual-responsive hydrogel is prepared, and the specific process is as follows:

and (I) adding 30g of dry and crushed hemp silk powder into one part of the prepared lithium hydroxide urea aqueous solution, fully and mechanically stirring, and repeatedly freezing, thawing and stirring for 5 times until the hemp silk powder is completely dissolved to obtain a viscous cellulose solution.

And (II) adding 15g of HA-MA into the cellulose solution obtained in the step (I), and fully stirring at the temperature of 0 ℃ under an ice bath condition to obtain the temperature-sensitive reversible hydrogel.

And (III) adding 2.5mL of 2959 photoinitiator into the temperature-sensitive reversible hydrogel system obtained in the step (II) and uniformly mixing to obtain the temperature/ultraviolet dual-responsiveness hydrogel for 3D printing.

(IV), a shaping process: and (3) 3D printing the temperature/ultraviolet dual-responsiveness hydrogel obtained in the step (III) to obtain a grid structure, and curing the grid structure by heating to 30 ℃. Subjecting to ultraviolet light (wavelength 275nm, intensity 15 mW/cm)²) And irradiating for 5min to realize secondary curing, thus finishing the shaping process of the printing structure.

The experimental results are comparable to example 1.

Test examples

This test example was conducted to test the properties of the temperature-sensitive reversible hydrogel and the temperature/ultraviolet dual-responsive hydrogel prepared in example 1. Wherein:

the temperature-sensitive reversibility of the temperature-sensitive reversible hydrogel prepared in example 1 is tested, and the test result is shown in fig. 1. The specific testing steps are as follows: adding 1mL of hydrogel into a bottle, setting different environmental temperatures through a water bath, taking out the bottle after the hydrogel temperature is constant after 10min, and taking out the bottle to take a side view.

Hydrogel biocompatibility of the temperature-sensitive reversible hydrogel prepared in example 1 was tested, and the test results are shown in fig. 2. The specific test is as follows: CCK8 experiment (adding common culture medium, specifically RPMI 1640 basic culture medium + 10% Fetal Bovine Serum (FBS) + 1% penicillin/streptomycin to control group, that is, the volume ratio of RPMI 1640 basic culture medium, fetal bovine serum and penicillin/streptomycin is 89:10: 1; adding maceration extract obtained by soaking temperature-sensitive reversible hydrogel in common culture medium to hydrogel group).

The temperature-sensitive reversible hydrogel prepared in example 1 was tested for extrusion moldability, and the test results are shown in fig. 3. The specific test is as follows: the hydrogel is extruded through a 23G needle into a linear structure, can be shaped by extrusion, and can be suspended between two bottles.

The 3D printed mesh structure of the temperature/uv dual-responsive hydrogel prepared in example 1 was tested, and the test results are shown in fig. 4. The specific test is as follows: printing by 3D printer (SunP CPD1/Biomaker) with needle temperature of-4 ℃ and stage temperature of 25 ℃.

From the above, the temperature-sensitive reversible hydrogel prepared by the invention has better extrusion moldability and can be used as a 3D printing material; meanwhile, the temperature-sensitive characteristic is reversible, curing can be realized when the temperature is increased to 10-40 ℃, the temperature-sensitive characteristic is in a solidification state, the flow state can be recovered when the temperature is reduced, the solidification state is convenient for forming a printing structure, and the flow state is recovered again, so that subsequent application of biological medicines, such as accelerating drug release and delivery, and the like can be facilitated

The temperature/ultraviolet dual-responsiveness hydrogel prepared by the method has good extrusion moldability, can be used as a 3D printing material, can respond to the change of external temperature, and has reversible temperature-sensitive characteristics (before being cured by ultraviolet irradiation); due to the addition of the photoinitiator, the temperature/ultraviolet dual-responsive hydrogel also has ultraviolet responsiveness, and secondary curing can be realized after ultraviolet irradiation for 0.5-10 min.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.