阅读说明：本技术 一种高强度甲壳素复合水凝胶材料及其制备方法与应用 (High-strength chitin composite hydrogel material and preparation method and application thereof ) 是由 罗丙红 李文彦 文伟 周长忍 于 2020-06-17 设计创作，主要内容包括：本发明属于生物医用材料领域,公开了一种高强度甲壳素复合水凝胶材料及其制备方法与应用。本发明的复合水凝胶材料由甲壳素为基体和表面呈负电性的甲壳素晶须为增强填料组成；所述的表面呈负电性的甲壳素晶须作为增强填料与甲壳素基体复合,晶须表面带有负电荷的基团可形成强静电排斥力,有效促进甲壳素晶须在甲壳素基体中的均匀分散,同时与基体能实现良好的界面结合,从而充分发挥晶须的增强效果,赋予甲壳素复合水凝胶材料优异的力学性能；同时,本发明的甲壳素复合水凝胶材料具有良好的生物相容性和成骨活性,在骨组织修复等生物医学领域具有良好的应用前景。(The invention belongs to the field of biomedical materials, and discloses a high-strength chitin composite hydrogel material as well as a preparation method and application thereof. The composite hydrogel material is composed of chitin as a matrix and chitin whisker with electronegativity on the surface as a reinforcing filler; the chitin whisker with the surface being electronegative is used as a reinforcing filler to be compounded with a chitin matrix, and a group with negative charges on the surface of the whisker can form strong electrostatic repulsive force, so that the uniform dispersion of the chitin whisker in the chitin matrix is effectively promoted, and meanwhile, the chitin whisker can realize good interface bonding with the matrix, thereby fully exerting the reinforcing effect of the whisker and endowing the chitin composite hydrogel material with excellent mechanical properties; meanwhile, the chitin composite hydrogel material has good biocompatibility and osteogenic activity, and has good application prospect in the biomedical fields of bone tissue repair and the like.)

1. A high-strength chitin composite hydrogel material is characterized by comprising chitin as a matrix and chitin whiskers with electronegative surfaces as reinforcing fillers.

2. The high strength chitin composite hydrogel material according to claim 1, wherein: the content of chitin is 0.1-15 wt%; the mass ratio of the chitin whisker with the electronegative surface to the chitin is 0.1:100-7: 100.

3. The high strength chitin composite hydrogel material according to claim 1, wherein: the chitin whisker with the electronegative surface is in a needle bar shape, the length of the chitin whisker is 200-350nm, and the diameter of the chitin whisker is 15-25 nm.

4. The high strength chitin composite hydrogel material according to claim 1, wherein: the chitin whisker with the electronegative surface is prepared by performing esterification reaction on chitin and maleic anhydride.

5. The high-strength chitin composite hydrogel material according to claim 4, characterized by comprising the following specific method steps: performing esterification reaction on chitin and maleic anhydride at 60-120 ℃ for 0.5-8h under inert atmosphere, and separating to obtain chitin whiskers with electronegative surfaces.

6. The method for preparing the high-strength chitin composite hydrogel material according to any one of claims 1-5, characterized by comprising the steps of: preparing chitin whisker with electronegative surface into water suspension, mixing with chitin solution, and placing in ethanol solution for physical crosslinking to obtain the high-strength chitin composite hydrogel material.

7. The method for preparing the high-strength chitin composite hydrogel material according to claim 6, wherein: in the aqueous suspension, the concentration of the chitin whiskers with electronegative surfaces is 0.1-7 wt%.

8. The method for preparing the high-strength chitin composite hydrogel material according to claim 6, wherein: the chitin solution is obtained by dissolving chitin in alkaline ionic liquid.

9. The method for preparing the high-strength chitin composite hydrogel material according to claim 6, wherein the physical crosslinking in an ethanol solution comprises the following steps: and casting the mixed solution on a mould, and then soaking in 30-100 wt% ethanol aqueous solution at the temperature of-15-35 ℃ for physical crosslinking for 0.5-24h to obtain the high-strength chitin composite hydrogel material.

10. Use of the high strength chitin composite hydrogel material of any one of claims 1-5 in the field of biomedical materials.

Technical Field

The invention belongs to the field of biomedical materials, and particularly relates to a high-strength chitin composite hydrogel material as well as a preparation method and application thereof.

Background

Bone damage has become a widespread and increasingly serious problem due to trauma, genetic disease and progressive aging, particularly bone defects caused by high-energy trauma are often accompanied by periosteal defects. Research has shown that periosteum plays a very critical role in bone regeneration, and the absence of periosteum may impair the progress of bone regeneration, resulting in prolonged or even no healing time at the site of bone injury. Therefore, it is very important to develop an advanced periosteal biomaterial having bone repair properties. Chitin is a semi-crystalline natural polysaccharide with rich sources, is widely distributed in shells of crustaceans such as shrimps, crabs and the like, and is the second largest renewable resource on the earth. Because of excellent properties such as good biocompatibility, biodegradability, high hydrophilicity, good antibacterial property, good osteogenic activity and the like, the composite material is widely applied to the field of biomedical materials. However, chitin has strong hydrogen bonding between molecules and inside molecules, and is difficult to dissolve in common solvents, so that it is difficult to further process chitin. Through research, the ionic liquid can be adopted to dissolve the chitin, which has great significance for expanding the application of the chitin in the field of biomedical materials (CN 103059320A).

Hydrogels with good physicochemical and biological properties are the first choice for the construction of periosteal biomaterials, which are able to retain large amounts of water and have a hydrophilicity similar to that of the natural extracellular matrix. Therefore, the chitin hydrogel can be used as a good choice for a periosteum biological material by integrating the performance advantages of natural polysaccharide chitin and the hydrogel; however, the use of single chitin hydrogel as a periosteal repair material still has the defects of weak mechanical strength and elasticity.

In order to improve the mechanical property of the chitin hydrogel, adding nano-fillers such as halloysite nanotubes, hydroxyapatite particles and graphene oxide is a common method; however, the mechanical strength of the prepared chitin hydrogel is still not ideal enough, and the mechanical property is not greatly improved. Chitin whiskers (CHWs), a needle-like nano-single crystal obtained by acid hydrolysis of chitin, have not only excellent properties of chitin but also high strength, high modulus and a certain aspect ratio, and have attracted much attention as a polymer reinforcing filler in recent years. However, the chitin whiskers currently used for polymer reinforcing fillers are usually chitin whiskers with electropositive surfaces prepared by methods such as acidolysis, and the chitin whiskers are only stable in dispersion under acidic conditions, and are susceptible to dispersion under alkaline environments and are easy to agglomerate. However, the commonly used chitin-dissolved ionic liquid is strongly alkaline and has high ionic strength, which is not beneficial to the dispersion of the chitin whiskers with positive electricity in the matrix solution, so that the research report of using the chitin whiskers to reinforce the chitin-based hydrogel is not seen.

Therefore, finding an effective method to enable the chitin whisker to realize good dispersibility in the chitin matrix liquid solution has practical significance in more effectively exerting the mechanical enhancement effect of the chitin whisker.

Chitin whiskers are rod-like colloidal particles, the dispersion stability of which is similar to other colloidal systems and largely depends on two stabilizing mechanisms: electrostatic stabilization by surface charge groups and steric stabilization by surface adsorption or grafting of polymer chain contributions. It has been reported that acrylic acid is grafted on chitin nano-fibers to improve the dispersibility in alkaline aqueous solution (Carbohydrate polymers,2012,90(1): 623-. However, this process is complicated and requires the use of initiators and toxic reagents.

Therefore, the chitin whisker with electronegativity on the surface is obtained by designing a green and simple method, so that the dispersibility of the chitin whisker in the chitin ionic liquid is improved, and the prepared chitin whisker reinforced chitin matrix hydrogel has important significance in more excellent mechanical properties.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention mainly aims to provide a high-strength chitin composite hydrogel material, which is composed of a chitin as a matrix and chitin whiskers with electronegative surfaces as reinforcing fillers, wherein the chitin whiskers with electronegative surfaces have good dispersibility in the chitin matrix and good interface bonding with the matrix, and the excellent mechanical reinforcing effect of the chitin whiskers can be fully exerted, so that the composite hydrogel material is endowed with excellent mechanical properties.

The invention also aims to provide a preparation method of the high-strength chitin composite hydrogel material.

The invention further aims to provide application of the high-strength chitin composite hydrogel material.

In order to achieve the purpose, the invention adopts the following technical scheme:

a high-strength chitin composite hydrogel material is composed of a matrix made of chitin and reinforcing fillers made of chitin whiskers with negative surfaces.

In the high-strength chitin composite hydrogel material, the content of chitin is 0.1-15 wt%; the mass ratio of the chitin whisker with electronegative surface to the chitin is 0.1:100-7:100, preferably 1:100-5: 100.

Preferably, the chitin whisker with the electronegative surface is in a needle bar shape, the length is 200-350nm, and the diameter is 15-25 nm.

The chitin whisker with electronegative surface can be prepared by esterification reaction of chitin and maleic anhydride, and comprises the following specific steps: performing esterification reaction on chitin and maleic anhydride at 60-120 ℃ for 0.5-8h under inert atmosphere, and separating to obtain chitin whiskers with electronegative surfaces.

Preferably, the mass ratio of chitin to maleic anhydride is 1:5 to 1:40, more preferably 1: 20.

Preferably, the obtained chitin whiskers with the electronegative surfaces can be washed by ethanol and water, treated by alkali, freeze-dried and ground.

Preferably, the alkali treatment refers to soaking the product after the reaction in alkali liquor; preferably, the soaking time is 0.5-12 h; the alkali liquor can be dilute solution of sodium hydroxide and the like, and is more preferably 1mol/L NaOH aqueous solution. More specifically, the method comprises the following steps: the reaction product was immersed in 1mol/L aqueous NaOH solution at room temperature for 0.5 to 12 hours to complete the alkali treatment. The base treatment can convert the surface-modified carboxyl groups of the reaction product to carboxylate groups, which can then be centrifuged repeatedly with water to remove excess NaOH.

Preferably, the inert atmosphere can be a conventional inert atmosphere such as nitrogen, argon and the like; the maleic anhydride reacts with chitin after being melted at 55-100 ℃.

The invention also provides a preparation method of the high-strength chitin composite hydrogel material, which comprises the following steps: preparing chitin whisker with electronegative surface into water suspension, mixing with chitin solution, and placing in ethanol solution for physical crosslinking to obtain the high-strength chitin composite hydrogel material.

In the aqueous suspension, the concentration of the chitin whiskers with the surface being electronegative is preferably 0.1-7 wt%.

Further, the chitin whisker with the electronegative surface is prepared into water suspension, and is specifically obtained by adding the chitin whisker with the electronegative surface into water and homogenizing.

Preferably, the time for homogenization may be 0.5 to 5 hours; the homogenization can be carried out using a cell disruptor at a power of 100-500W.

Further, the chitin solution is preferably obtained by dissolving chitin in an alkaline ionic liquid. More preferably, the preparation method comprises the following steps: adding chitin into alkaline ionic liquid at-50 deg.C to-10 deg.C, stirring for 0.5-6 hr, transferring to 0-10 deg.C, and standing for 0.5-96 hr.

Preferably, the chitin solution contains 0.1-15 wt% of chitin.

Preferably, the basic ionic liquid can be composed of 10-30 wt% of strong base, 1-10 wt% of urea and/or thiourea, and water.

Preferably, the strong base may include at least one of KOH, NaOH, LiOH, and the like.

The chitin is preferably purified for reuse, and can comprise the following specific steps: stirring chitin powder with strong alkali and strong oxidant solution, washing with water until the washing liquid is neutral, freeze drying, and grinding.

Preferably, the strong alkaline solution may include NaOH, KOH, Ca (OH)₂And the like.

Preferably, the concentration of the strong alkali solution is 0.5-3 mol/L. The strong alkali solution is stirred and treated at normal temperature for 12-24 h.

Preferably, the strong oxidant may include NaClO₂、NaClO、H₂O₂And the like.

Preferably, the concentration of the strong oxidant solution is 0.01-0.5 mol/L. The strong oxidant solution may be adjusted to a pH of 4 with acetic acid. The strong oxidant solution is stirred and treated at the temperature of 60-90 ℃ for 1-8 h.

Further, the mixing may comprise the following specific steps: dropwise adding the chitin whisker water suspension with the surface being electronegative into the chitin solution, and stirring for 1-6h at 0-10 ℃.

Further, the physical crosslinking in the ethanol solution may comprise the following specific steps: and casting the mixed solution on a mould, and then soaking in 30-100 wt% ethanol aqueous solution at the temperature of-15-35 ℃ for physical crosslinking for 0.5-24h to obtain the high-strength chitin composite hydrogel material.

The mould can adopt different shapes and thicknesses according to requirements, for example, the mould for preparing the membrane material can be adopted, so that the high-strength chitin composite hydrogel membrane material is prepared.

Preferably, the obtained high-strength chitin composite hydrogel material can be washed with water for multiple times to remove residual chemicals of the alkaline ionic liquid.

The chitin composite hydrogel material is prepared by adopting chitin as a matrix and chitin whiskers with electronegative surfaces as reinforcing fillers. The chitin whisker with the electronegative surface has good dispersibility in a hydrogel system, realizes good interface bonding with a chitin matrix, and obviously enhances the mechanical property of the chitin hydrogel. The chitin composite hydrogel material prepared by the invention has excellent mechanical properties, high hydrophilicity, good antibacterial property and osteogenic activity, and good application prospect in the field of biomedical materials.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the method for preparing the chitin whisker with the electronegative surface has the characteristics of low cost, easy purification and environmental friendliness, and the chitin whisker is compounded with the chitin matrix to prepare the high-strength chitin composite hydrogel material, so that the operation is simple and efficient.

(2) Compared with the conventional method that chitin whiskers with positively charged surfaces are used as the reinforcing filler of the polymer matrix, the method provided by the invention has the advantages that carboxyl groups on the surfaces of the chitin whiskers with negatively charged surfaces are ionized in the strong-alkaline chitin matrix ionic liquid, so that a large number of carboxylate radicals with negative charges are generated on the surfaces of the chitin whiskers to form strong electrostatic repulsive force, and the uniform dispersion of the chitin whiskers in the basic chitin ionic liquid matrix is effectively promoted without flocculation.

(3) The invention adopts the chitin whisker with negative surface as the reinforcing filler, the components of the chitin whisker are the same as those of a chitin substrate, and good interface bonding can be expected to be realized between the substrate and the whisker through hydrogen bonds and electrostatic interaction.

(4) The chitin whisker with electronegative surface is adopted as the reinforcing filler to be compounded with the chitin matrix, the dispersion of the whisker in the matrix is good, and the whisker and the matrix have good interface bonding, so that the reinforcing effect of the whisker can be fully exerted, the chitin composite hydrogel material is endowed with excellent mechanical properties, and the tensile strength of the chitin composite hydrogel material can reach 2-7 MPa.

(5) The high-strength chitin composite hydrogel material prepared by the invention has good biocompatibility, can realize good osteogenesis activity, and is expected to have good application prospect in the field of biomedical materials such as bone tissue repair and the like as an artificial periosteum.

Drawings

Fig. 1 is a transmission electron micrograph of chitin whiskers (mCHWs) having a negatively charged surface in example 1.

FIG. 2 is a scanning electron micrograph of the high strength chitin composite hydrogel material of example 9; wherein (A) is the surface micro-morphology of the chitin composite hydrogel material, and (B) is the cross-section micro-morphology of the chitin composite hydrogel material.

Fig. 3 is a stress-strain curve of the high-strength chitin composite hydrogel materials of example 9 and comparative example 1.

Fig. 4 is a stress-strain curve of the chitin composite hydrogel materials of example 9 and comparative examples 1 and 2.

Fig. 5 is a graph showing cell proliferation of the chitin complex hydrogel materials of example 9 and comparative example 1.

Fig. 6 is a graph showing the secretion of alkaline phosphatase from the chitin hydrogel materials of example 9 and comparative example 1.

Detailed Description

The invention is further illustrated below with reference to specific examples, but the embodiments of the invention are not limited thereto. Various changes or modifications may be made by those skilled in the art based on the embodiments of the present invention, and equivalents may also fall within the scope of the claims appended to this application. All the raw materials and reagents used in the present invention are commercially available raw materials and reagents, unless otherwise specified.