A self-healing collagen hydrogel material and preparation method thereof

Abstract

The present invention relates to the field of biomaterials, and in particular to a self-healing collagen hydrogel material and a preparation method thereof. The present invention provides a method for preparing a self-healing collagen hydrogel material, comprising the following steps: (1) dissolving a solid collagen material in water, and adjusting the pH value of the aqueous solution to greater than or equal to 3 but less than or equal to 6 by an acidic solution to form a homogeneous aqueous solution; (2) adjusting the pH value of the collagen aqueous solution obtained in step (1) to greater than or equal to 7 but less than or equal to 8 by an alkaline solution at 0°C; (3) adding a specific ion / molecule pair to the solution obtained in step (2) at 4°C; (4) placing the solution obtained in step (3) at 37°C for pre-coagulation treatment; and (5) placing the solution obtained in step (4) at 4°C for storage. The self-healing collagen hydrogel material prepared by the method of the present invention can achieve self-healing properties of the material by shear force or temperature change.

Description

Technical Field

[0001] The present invention relates to the field of biomaterials, and in particular to a self-healing collagen hydrogel material and a preparation method thereof. Background Art

[0002] Self-healing hydrogel materials refer to hydrogels that can self-repair after being damaged or deformed by external mechanical forces. The mechanical and dynamic properties of the materials can be precisely controlled through structural design to mimic the self-repair behavior of living tissues. Depending on the preparation method, self-healing hydrogel materials can be divided into physical self-healing hydrogel materials and chemical self-healing hydrogel materials. Physical self-healing hydrogel materials mainly rebuild the network through ionic bonds, hydrogen bonds, hydrophobic interactions, etc. For example, injectable hydrogel materials with self-healing properties are essentially soft condensed substances based on reversible chemistry, which can temporarily fluidize under shear stress and then restore their original mechanical properties.

[0003] Collagen is the primary structural protein in connective tissue and is widely distributed in tissues and organs such as bone, skin, blood vessels, ligaments, cartilage, muscles, and tendons, accounting for 25% to 30% of total animal protein. Conventional collagen hydrogels lack self-healing properties, meaning they cannot return to a fluid state after forming a hydrogel, nor do they exhibit the reversible gel-sol transition.

[0004] The self-healing collagen hydrogel material of the present invention can achieve self-healing properties of the material through shear force or temperature change. Summary of the Invention

[0005] One object of the present invention is to provide a method for preparing a self-healing collagen hydrogel material, which can make the prepared collagen hydrogel material have self-healing properties.

[0006] Another object of the present invention is to provide a self-healing collagen hydrogel material that can achieve self-healing properties of the material through shear force or temperature change.

[0007] A method for preparing a self-healing collagen hydrogel material, comprising the following steps in sequence:

[0008] (1) dissolving a solid collagen material in water, and adjusting the pH value of the aqueous solution to greater than or equal to 3 but less than or equal to 6 using an acidic solution to form a homogeneous aqueous solution;

[0009] (2) adjusting the pH value of the collagen aqueous solution obtained in step (1) to greater than or equal to 7 but less than or equal to 8 at 0° C. using an alkaline solution;

[0010] (3) adding a specific ion / molecule pair to the solution obtained in step (2) at 4°C;

[0011] (4) placing the solution obtained in step (3) at 37° C. for pre-coagulation;

[0012] (5) The solution obtained in step (4) was stored at 4°C for future use.

[0013] The present invention provides a method for preparing a self-healing collagen hydrogel material, wherein the concentration of the collagen aqueous solution in step (1) is greater than or equal to 0.1wt.% but less than or equal to 10wt.%. Only by selecting an appropriate concentration of the collagen aqueous solution can the self-healing collagen hydrogel material formed have significant self-healing properties. When the concentration of the collagen aqueous solution is lower than 0.1wt.%, a stable collagen hydrogel cannot be formed after step (4), and the material can only be in a fluid state under normal temperature conditions, and the material cannot have self-healing properties; when the concentration of the collagen aqueous solution is greater than 10wt.%, the viscosity of the prepared material is very high, and it is easy to form a hydrogel. The fluidity of the material cannot be restored by shear force or temperature change, and the material cannot have self-healing properties. The concentration of the collagen aqueous solution is selected to be greater than or equal to 0.1wt.% but less than or equal to 10wt.%. The collagen hydrogel material prepared by the preparation method of the present invention can temporarily have fluidity under the action of shear force or after temperature change treatment at room temperature, presenting a fluid state, and then recovering the gel state to form a stable collagen hydrogel. The material apparently has gel-sol reversible properties and has self-healing properties.

[0014] The present invention provides a method for preparing a self-healing collagen hydrogel material, wherein the acidic solution in step (1) comprises at least one of salicylic acid, lactic acid, sulfuric acid, tartaric acid, citric acid, phosphoric acid, oxalic acid, acetic acid, oxalic acid, succinic acid, hydrochloric acid, maleic acid, benzoic acid, nitric acid, malic acid, nicotinic acid, sodium dihydrogen phosphate, and formic acid. The concentration range of the acidic solution is 0.1–10 M. The selection of a suitable acidic solution and concentration is mainly to fully dissolve the solid collagen material, while adding a trace amount of acidic solution as much as possible to avoid affecting the concentration of the collagen solution. The selection of the concentration of the acidic solution is related to the acidity of the acidic molecules used. Acidic molecules with stronger acidity can be selected at a lower concentration, while acidic molecules with weaker acidity can be selected at a higher concentration. Such a selection can ensure that the pH value of the aqueous solution can be adjusted to greater than or equal to 3 but less than or equal to 6 by adding the acidic solution, and avoid excessive fluctuations in the pH value of the aqueous solution after the addition of the acidic solution, which exceeds the preset range. In addition, the selected acidic molecules also work synergistically with other reagents added in subsequent steps to ensure that the material has gel-sol reversible properties and exhibits self-healing properties.

[0015] The present invention provides a method for preparing a self-healing collagen hydrogel material, wherein the alkaline solution in step (2) comprises at least one of tetramethylethylenediamine, sodium hydroxide, triethylamine, sodium carbonate, potassium hydroxide, calcium hydroxide, magnesium hydroxide, aqueous ammonia, disodium hydrogen phosphate, and sodium bicarbonate. The concentration range of the alkaline solution is 0.1–10 M. The selection of a suitable alkaline solution and concentration is mainly to accurately control the pH value of the collagen aqueous solution to be greater than or equal to 7 but less than or equal to 8, while the addition of a trace amount of alkaline solution does not significantly change the concentration of the collagen aqueous solution. Only when the pH value of the collagen aqueous solution is in the range of greater than or equal to 7 but less than or equal to 8 can the collagen aqueous solution form a collagen hydrogel, and only then can it be treated by shear force or temperature change to present a fluid state, and then restore the hydrogel state again, making it possible for the material to have self-healing properties. In addition, the selected alkaline molecules also synergize with other reagents added in subsequent steps to ensure that the material has gel-sol reversible properties and exhibits self-healing properties.

[0016] The present invention provides a method for preparing a self-healing collagen hydrogel material, wherein the specific ion / molecule pair in step (3) includes Tris-HAc, Tris-H2PO4 - 、Tris-NH4 + 、Tris-H + , Tris-lysine hydrochloride, Tris-lysine hydrochloride-ethylenediaminetetraacetic acid anion, HPO4 2- -Citric acid, HCO3 - -Citric acid, CO3 2- -Citric acid, H2PO4 - -Citric acid, PO4 3- -Citric acid, Ac - -Citric acid, Ac - -H + -NH4 + 、HAc-Ac - 、HAc-Ac - -NH4 + PO4 3- -HPO4 2- PO4 3- -H2PO4-, HPO4 2- -H2PO 4- 、HPO4 2- -NH4 + 、H2PO4 - -HCO3 - 、H2PO4 - -CO3 2- At least one of .

[0017] The present invention provides a method for preparing a self-healing collagen hydrogel material, wherein the concentration range of the specific ion / molecule pair in step (3) is 0.01–20M. The addition of the specific ion / molecule pair is mainly to regulate the overall ionic environment, ionic strength, intermolecular interaction force, etc. of the material, as well as the charge level and distribution on the surface of the collagen molecules, so that the collagen hydrogel material can have dynamic mechanical properties under specific conditions, that is, the collagen hydrogel material can temporarily change from a gel state to a fluid state when subjected to shear force or temperature change treatment, and then can return to the gel state, and the material apparently has certain self-healing properties. On the other hand, step (3) cooperates with steps (1) and (2) rather than operating in isolation, so that the collagen hydrogel material can have self-healing properties. The selection of ion / molecule pairs is also related to their concentration. For example, when it is necessary to enhance the ionic strength of the aqueous solution, a high concentration of ion-containing components will be selected, while a low concentration of molecular components will be selected; when it is necessary to enhance the intermolecular interaction force (such as hydrogen bonding) of the aqueous solution, a high concentration of molecular components will be selected, while a low concentration of ion-containing components will be selected. This is the only way to ensure that the final collagen hydrogel material exhibits self-healing properties under specific conditions.

[0018] The present invention provides a method for preparing a self-healing collagen hydrogel material, which differs from the prior art in that conventional collagen hydrogels are usually formed from an acidic soluble state to a neutral gel state by regulating the pH environment of a collagen aqueous solution. By regulating only the single factor of pH value, the resulting collagen hydrogel material does not have self-healing properties. Once the hydrogel structure is damaged or deformed by external mechanical forces, for example, the overall hydrogel structure is cut into several partial hydrogel structures, the material does not have the ability to repair the damage autonomously, that is, the several broken hydrogel structures cannot be reconnected to restore the overall hydrogel structure by shear force or temperature change. In actual application scenarios, conventional collagen hydrogel materials cannot be transformed from a gel state to a fluid state and then restored to a gel state by shearing methods such as stirring; conventional collagen hydrogel materials cannot be transformed into a flowing collagen aqueous solution by injection and restored to a gel state after injection; after conventional collagen hydrogel materials are broken, the broken parts cannot be re-fused together by temperature change alone to restore the broken hydrogel material to a complete structure. However, in addition to regulating the pH value of the collagen hydrogel material, the present invention further dynamically regulates the solution environment of the collagen aqueous solution during the preparation process, and balances the interaction forces between collagen molecules through specific ion / molecular components, so that the collagen hydrogel finally prepared exhibits self-healing properties under specific circumstances. Apparently, the broken hydrogel structures can be reconnected to restore the overall hydrogel structure through shear force or temperature changes. In actual application scenarios, the self-healing collagen hydrogel material can be transformed from a gel state to a fluid state through shearing methods such as stirring, and then restored to a gel state; the self-healing collagen hydrogel material can be transformed into a flowing collagen aqueous solution through injection, and restore to a gel state after injection; the broken self-healing collagen hydrogel can be re-fused together at the broken parts through temperature changes, so that the broken hydrogel material can restore its complete structure.

[0019] A self-healing collagen hydrogel material is prepared using the method for preparing a self-healing collagen hydrogel material of the present invention.

[0020] The present invention provides a self-healing collagen hydrogel material, wherein the material can be used by injection at room temperature, the material is in a gel state initially, and is in a fluid state during the injection process, and the material returns to a gel state after injection. Conventional collagen hydrogels form insoluble substances such as flocs or gels due to the self-assembly behavior of collagen molecules. These insoluble substances cannot be converted into a fluid state by the shear force of a fine syringe and a needle during the injection process, and can easily clog the syringe or needle, making it impossible to achieve the injection operation. The self-healing collagen hydrogel of the present invention can be temporarily converted from a gel state to a fluid state under the shear force of a fine syringe and a needle, can flow freely, can pass through a syringe or a needle smoothly, can achieve the injection operation, and the material can return to a gel state after injection.

[0021] The present invention discloses a self-healing collagen hydrogel material. A gel-like material that breaks at room temperature can self-heal at the fracture site after being cooled to 0°C and restored to room temperature. Conventional collagen hydrogel materials cannot change their gel state after being cooled at room temperature, nor can the fractured parts be re-fused to achieve self-repair. However, the self-healing collagen hydrogel of the present invention, after being mechanically broken, is cooled to 0°C, causing the material at the fracture site to temporarily transition to a fluid state, allowing the fractured parts to re-fuse, and then returning to a gel state, connecting the fractured parts into a complete structure, exhibiting the ability to self-repair damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The self-healing performance effect diagram of the self-healing collagen hydrogel material prepared by Example 1 of the preparation method of the self-healing collagen hydrogel material of the present invention (wherein: A is a sample broken under room temperature conditions, and B is a sample that self-healed after being cooled to 0°C and then restored to room temperature conditions);

[0023] Figure 2 This is a diagram showing the injectable performance of the self-healing collagen hydrogel material prepared by Example 2 of the method for preparing the self-healing collagen hydrogel material of the present invention. DETAILED DESCRIPTION

[0024] Example 1

[0025] A method for preparing a self-healing collagen hydrogel material, comprising the following steps in sequence:

[0026] (1) dissolving the solid collagen material in water, and adjusting the pH value of the aqueous solution to 4 with 0.5 M oxalic acid solution to form a homogeneous aqueous solution;

[0027] (2) adjusting the pH of the collagen aqueous solution obtained in step (1) to 7 with 0.5 M triethylamine solution at 0°C;

[0028] (3) At 4°C, add HPO4 to the solution obtained in step (2). 2- -citric acid and Tris-lysine hydrochloride-ethylenediaminetetraacetic acid ion, with concentrations of 5 M and 2 M, respectively;

[0029] (4) placing the solution obtained in step (3) at 37° C. for pre-coagulation;

[0030] (5) The solution obtained in step (4) was stored at 4°C for future use.

[0031] The gel-like material that is broken under normal temperature conditions can be self-healed after being cooled to 0℃ and then restored to normal temperature. Figure 1 .

[0032] Example 2

[0033] A method for preparing a self-healing collagen hydrogel material, comprising the following steps in sequence:

[0034] (1) dissolving the solid collagen material in water, and adjusting the pH value of the aqueous solution to 5 with a 2 M maleic acid solution to form a homogeneous aqueous solution;

[0035] (2) adjusting the pH of the collagen aqueous solution obtained in step (1) to 8 with 2 M sodium bicarbonate solution at 0°C;

[0036] (3) At 4°C, add H2PO4 to the solution obtained in step (2). - -HCO3 - and Tris-H2PO4 - , concentrations were 3M and 6M, respectively;

[0037] (4) placing the solution obtained in step (3) at 37° C. for pre-coagulation;

[0038] (5) The solution obtained in step (4) was stored at 4°C for future use.

[0039] The material that is in gel state at room temperature becomes fluid during injection and returns to gel state after injection. See the injectability effect diagram. Figure 2 , Figure 2 The needle in the test is a 25G needle with an inner diameter of 250um, and the material can be injected using this needle.

[0040] Example 3

[0041] A method for preparing a self-healing collagen hydrogel material, comprising the following steps in sequence:

[0042] (1) dissolving the solid collagen material in water, and adjusting the pH value of the aqueous solution to 6 with a 1 M malic acid solution to form a homogeneous aqueous solution;

[0043] (2) At 0°C, the pH value of the collagen aqueous solution obtained in step (1) was adjusted to 7.2 using 5M disodium hydrogen phosphate solution;

[0044] (3) At 4°C, add Tris-lysine hydrochloride and Ac - -H + -NH4 + , concentrations were 2M and 7M, respectively;

[0045] (4) placing the solution obtained in step (3) at 37° C. for pre-coagulation;

[0046] (5) The solution obtained in step (4) was stored at 4°C for future use.

[0047] The material in a gel state that is broken under normal temperature conditions (the material is the self-healing collagen hydrogel material prepared in this embodiment) is cooled to 0° C. and then restored to normal temperature conditions, and the broken parts of the material can achieve self-healing.

[0048] In other embodiments of the present invention, the self-healing collagen hydrogel material prepared by this embodiment is in a gel state at room temperature, in a fluid state during the injection process, and the material returns to a gel state after injection. That is, the self-healing collagen hydrogel material prepared by this embodiment can temporarily return to a fluid state after forming a hydrogel, and has a gel-sol reversible property.

[0049] In summary, the preparation method of the self-healing collagen hydrogel of the present invention further dynamically controls the solution environment of the collagen aqueous solution during the preparation process on the basis of conventionally controlling the pH value of the collagen hydrogel material, and balances the interaction force between the collagen molecules through specific ion / molecular components, so that the collagen hydrogel finally prepared exhibits self-healing properties under specific circumstances. The collagen hydrogel material prepared by the preparation method of the self-healing collagen hydrogel of the present invention can be used by injection at room temperature. The initial state of the material is a gel state, and it is in a fluid state during the injection process. After injection, the material returns to a gel state. The self-healing collagen hydrogel material prepared by the preparation method of the present invention that is in a gel state and broken at room temperature can be self-healed after being cooled to 0°C and restored to room temperature. Conventional collagen hydrogels only control the pH environment of the material. Once the collagen hydrogel is formed, the material cannot achieve self-healing properties, cannot be transformed from a gel state to a fluid state by shearing methods such as stirring, cannot be transformed into a flowing collagen aqueous solution by injection, and cannot be self-repaired after the material is damaged or deformed by external mechanical forces.

[0050] The embodiments described above are merely descriptions of preferred implementations of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A method for preparing a self-healing collagen hydrogel material, characterized in that: The following steps are included in sequence: (1) dissolving the solid collagen material in water, and adjusting the pH value of the aqueous solution to 4 with a 0.5 M oxalic acid solution to form a homogeneous aqueous solution; (2) adjusting the pH of the collagen aqueous solution obtained in step (1) to 7 with 0.5 M triethylamine solution at 0°C; (3) At 4°C, add HPO4 to the solution obtained in step (2). 2- -citric acid and Tris-lysine hydrochloride-ethylenediaminetetraacetic acid ion, with concentrations of 5 M and 2 M, respectively; (4) placing the solution obtained in step (3) at 37° C. for pre-coagulation; (5) The solution obtained in step (4) was stored at 4°C for later use; The prepared material in a gel state that is broken under room temperature conditions can be cooled to 0°C and then restored to room temperature conditions, and the broken parts of the material can achieve self-healing.

2. A method for preparing a self-healing collagen hydrogel material, characterized in that: The following steps are included in sequence: (1) dissolving the solid collagen material in water, and adjusting the pH value of the aqueous solution to 5 with a 2 M maleic acid solution to form a homogeneous aqueous solution; (2) adjusting the pH of the collagen aqueous solution obtained in step (1) to 8 with 2 M sodium bicarbonate solution at 0°C; (3) At 4°C, add H2PO4 to the solution obtained in step (2). - -HCO3 - and Tris-H2PO4 - , concentrations were 3M and 6M, respectively; (4) placing the solution obtained in step (3) at 37° C. for pre-coagulation; (5) The solution obtained in step (4) was stored at 4°C for later use; The prepared material in a gel state at room temperature is injected through a 25G needle with an inner diameter of 250 μm. It is in a fluid state during the injection process and returns to a gel state after the injection.

3. A method for preparing a self-healing collagen hydrogel material, characterized in that: The following steps are included in sequence: (1) dissolving the solid collagen material in water, and adjusting the pH value of the aqueous solution to 6 with a 1 M malic acid solution to form a homogeneous aqueous solution; (2) At 0°C, the pH value of the collagen aqueous solution obtained in step (1) was adjusted to 7.2 using 5M disodium hydrogen phosphate solution; (3) At 4°C, add Tris-lysine hydrochloride and Ac - -H + -NH4 + , concentrations were 2M and 7M, respectively; (4) placing the solution obtained in step (3) at 37° C. for pre-coagulation; (5) The solution obtained in step (4) was stored at 4°C for later use; The prepared material in a gel state that is broken under room temperature conditions can be cooled to 0°C and then restored to room temperature conditions, and the broken parts of the material can achieve self-healing.

4. A self-healing collagen hydrogel material prepared by the method for preparing a self-healing collagen hydrogel material according to any one of claims 1 to 3.

5. The self-healing collagen hydrogel material according to claim 4, characterized in that: The material can be used by injection at room temperature. The initial state of the material is gel, and it becomes fluid during the injection process. After injection, the material returns to the gel state.

6. The self-healing collagen hydrogel material according to claim 4, characterized in that: A gel-like material that breaks at room temperature can self-heal at the fracture site after being cooled to 0°C and restored to room temperature.

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