A photocrosslinked chitin whisker composite liquid crystal gel material, its preparation method and application

Abstract

The present invention discloses a photocrosslinked chitin whisker composite liquid crystal gel material, its preparation method, and application. The present invention obtains a chitin liquid crystal having a structure that mimics the extracellular matrix of natural bone cells by ultrasonically treating a chitin whisker suspension; then, while maintaining the chitin liquid crystal texture, a photocrosslinking monomer and a photocrosslinking initiator are added to the chitin liquid crystal; finally, the three are evenly mixed and placed under ultraviolet and visible light for illumination to prepare a photocrosslinked chitin whisker composite liquid crystal gel material. The composite liquid crystal gel material obtained by the present invention has a simple preparation method and has viscoelasticity and liquid crystal state that mimic the extracellular matrix of natural bone cells. It has morphological stability suitable for material application, good mechanical properties, excellent cell affinity, and osteogenic activity. It can be used in the biomedical field, especially in the field of bone tissue repair, and has good application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of biomedical composite materials, and particularly relates to a photo-crosslinked chitin whisker composite liquid crystal gel material, a preparation method and an application thereof. Background Art

[0002] Bone defects are a common problem in orthopedics. Current treatments for bone defects include autologous bone transplantation, allogeneic bone transplantation, and bone tissue engineering. However, the first two methods have various limitations, necessitating the development of materials that meet the requirements of bone tissue engineering. Viscoelasticity is a universal characteristic of the extracellular matrix, and a growing body of research indicates that this matrix's viscoelasticity directly influences cell proliferation, differentiation, and migration. Of particular note, the natural bone extracellular matrix is primarily composed of collagen fibers in a liquid-crystalline state. Their anisotropic surface structure facilitates cell adhesion, proliferation, and differentiation, as well as regulates the deposition of calcium and phosphate salts, promoting bone regeneration in multiple ways. However, the in vitro extraction of collagen and the preparation of collagen fiber scaffolds with a liquid-crystalline texture are cumbersome and require demanding conditions. Furthermore, the mechanical properties of these collagen fiber scaffolds are poor, making them difficult to meet the mechanical properties required for bone tissue engineering. Therefore, developing a bone tissue repair material that mimics the viscoelasticity and liquid-crystalline state of the natural bone extracellular matrix through simple preparation methods is of great significance.

[0003] Hydrogels, due to their high water content and cross-linked three-dimensional network structure, possess viscoelastic properties. They are a typical class of soft, wet materials that mimic the viscoelastic properties of natural extracellular matrix. They provide a suitable microenvironment for cell proliferation, effectively promoting cell adhesion, proliferation, and differentiation. Consequently, hydrogels have become a research hotspot in bone tissue engineering in recent years. Chitin, a natural marine polysaccharide, is widely available. Simple chemical treatment of chitin can produce needle-shaped chitin whiskers, which possess excellent mechanical properties, biocompatibility, cell affinity, and osteogenic activity. More importantly, under certain conditions, chitin whiskers can self-assemble to form a chiral nematic liquid crystal texture similar to that of natural bone extracellular matrix. However, few studies have been conducted on how to impart the morphological stability and mechanical properties required for this natural bone extracellular matrix-mimicking liquid crystal state, thereby fully utilizing the liquid crystal state of these natural polysaccharide whiskers to guide cell behavior and osteogenic differentiation.

[0004] In the previously disclosed invention patent CN 202011038862, a polylactic acid composite material modified with a chitin whisker liquid crystal elastomer and its preparation method and application are disclosed. In this invention patent, the prepared chitin whisker liquid crystal elastomer is modified on the surface of a polylactic acid film to prepare a composite material. However, the chitin whisker liquid crystal elastomer in this invention patent is formed by directly cross-linking chitin whiskers with a cross-linking agent. Since chitin whiskers are rigid needle-shaped and can only be suspended in water, the cross-linking reaction is a heterogeneous reaction. Moreover, the content of free amino groups on the chitin whiskers is low. Both factors lead to the low cross-linking density of the prepared chitin whisker liquid crystal elastomer, poor mechanical strength, insufficient molding ability, and limited use as a bone tissue engineering scaffold material alone. Therefore, how to design and prepare chitin whisker-based liquid crystal gels with good mechanical properties and highly controllable mechanical properties to achieve the real application of this type of chitin whisker-based liquid crystal gel that mimics the viscoelasticity and liquid crystal state of natural bone extracellular matrix in bone tissue engineering is of great practical significance. Summary of the Invention

[0005] The primary purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for preparing a photo-crosslinked chitosan whisker composite liquid crystal gel material.

[0006] Another object of the present invention is to provide a photo-crosslinked chitosan whisker composite liquid crystal gel material obtained by the above preparation method.

[0007] Another object of the present invention is to provide an application of the above-mentioned photo-crosslinked chitosan whisker composite liquid crystal gel material.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] A method for preparing a photo-crosslinked chitosan whisker composite liquid crystal gel material comprises the following steps:

[0010] (1) preparing chitosan whiskers into a chitosan whisker suspension, and ultrasonically treating the chitosan whisker suspension to obtain chitosan whisker liquid crystals;

[0011] (2) adding a photocrosslinking monomer and a photocrosslinking initiator to the chitosan whisker liquid crystal obtained in step (1) to obtain a mixed suspension;

[0012] (3) cross-linking the mixed suspension obtained in step (2) under light irradiation to obtain a photo-crosslinked chitosan whisker composite liquid crystal gel material.

[0013] The chitosan whiskers described in step (1) are preferably at least one of hydrochloric acid-decomposed chitosan whiskers (CHWs) and maleic anhydride-treated chitosan whiskers (mCHWs).

[0014] The hydrochloric acid-decomposed chitosan whiskers (CHWs) are preferably prepared by the following steps: uniformly dispersing chitosan powder in a hydrochloric acid solution and performing an acid decomposition reaction under a nitrogen atmosphere; after the reaction is completed, solid-liquid separation is performed, the obtained solid is dialyzed, and the dialyzed product is dried to obtain hydrochloric acid-decomposed chitosan whiskers.

[0015] The concentration of the hydrochloric acid solution is preferably 1 to 10 mol / L, and more preferably 1.5 to 3 mol / L.

[0016] The acid hydrolysis reaction is preferably carried out at a temperature of 80 to 95° C. for 1 to 6 hours; more preferably at a temperature of 90° C. for 2 to 4 hours.

[0017] The solid-liquid separation method is preferably centrifugation.

[0018] The centrifugal conditions are preferably 4000-8000 rpm for 10-15 minutes.

[0019] The dialysis is preferably performed in a dialysis bag with a molecular weight cut-off of 8,000 to 20,000 D for 7 to 14 days; more preferably, the dialysis is performed in a dialysis bag with a molecular weight cut-off of 10,000 D for 7 to 12 days.

[0020] The drying is preferably freeze-drying.

[0021] The freeze-drying conditions are preferably -50 to -45°C and a vacuum degree of 0.1 to 0.5 Pa for 24 hours.

[0022] The maleic anhydride chitosan whiskers (mCHWs) are preferably prepared by the following steps: heating and dissolving maleic anhydride (maleic anhydride) to obtain a maleic anhydride liquid, then adding chitosan powder and stirring evenly to form a suspension, and performing a maleic anhydride reaction under a nitrogen atmosphere; after the reaction is completed, centrifuging the mixture for solid-liquid separation, decanting the supernatant, adding deionized water, and repeating the centrifugation operation until the supernatant is neutral, and drying the separated solid to obtain maleic anhydride chitosan whiskers.

[0023] The heating is preferably heated to 60-80°C.

[0024] The amount of chitosan powder is preferably calculated based on the mass ratio of maleic anhydride:chitosan powder = (100-150): (5-20); more preferably, based on the mass ratio of maleic anhydride:chitosan powder = (100-150): (5-10).

[0025] The conditions for the maleic anhydride reaction are preferably: reaction at a reaction temperature of 100-135° C. for 2-6 hours; more preferably: reaction at a reaction temperature of 105-135° C. for 3-6 hours.

[0026] The solid-liquid separation method is preferably centrifugation.

[0027] The centrifugal conditions are preferably centrifuged in a centrifuge at a rotation speed of 5000 to 9000 rpm for 10 to 20 minutes.

[0028] The drying is preferably freeze-drying.

[0029] The freeze-drying conditions are preferably -50 to -45°C and a vacuum degree of 0.1 to 0.5 Pa.

[0030] The chitosan whiskers described in step (1) preferably have a length of 100 to 1000 nm and a diameter of 10 to 50 nm; more preferably, the chitosan whiskers have a length of 150 to 350 nm and a diameter of 15 to 30 nm.

[0031] The chitosan whisker suspension in step (1) is preferably prepared by adding chitosan whiskers into deionized water and stirring and dispersing the mixture.

[0032] The concentration of the chitosan whisker suspension in step (1) is preferably 5 to 15 wt %, more preferably 8 to 12 wt %.

[0033] The ultrasonic treatment in step (1) is preferably performed using a cell disruptor.

[0034] The ultrasonic treatment conditions in step (1) are preferably: ultrasonic treatment at an ultrasonic power of 300-600 W for 1-3 h; more preferably: ultrasonic treatment at an ultrasonic power of 450-500 W for 2.5-3 h.

[0035] The photocrosslinking monomer described in step (2) is preferably at least one of polyethylene glycol diacrylate (PEGDA), methacrylated gelatin (GelMA) and methacrylated hyaluronic acid (HAMA).

[0036] The mass ratio of the chitin whiskers in step (1) to the photocrosslinking monomer in step (2) is preferably chitin whiskers: photocrosslinking monomer = 1 to 3:5; more preferably chitin whiskers: photocrosslinking monomer = 1.3 to 2.1:5.

[0037] The photocrosslinking initiator described in step (2) is preferably at least one of lithium phenyl-2,4,6-trimethylbenzoyl phosphite (LAP), 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I2959) and riboflavin.

[0038] The concentration of the photocrosslinking monomer in step (2) in the mixed suspension is preferably 5 to 30 wt %, and more preferably 20 to 30 wt %.

[0039] The concentration of the photocrosslinking initiator in step (2) in the mixed suspension is preferably 0.1 to 1 wt %; more preferably 0.1 to 0.7 wt %.

[0040] The light in step (3) is preferably ultraviolet light or visible light.

[0041] The wavelength of the light in step (3) is preferably 300 to 500 nm; more preferably 320 to 450 nm.

[0042] The irradiation time of the light irradiation in step (3) is preferably 60 to 600 s; more preferably 120 to 300 s.

[0043] A photo-crosslinked chitosan whisker composite liquid crystal gel material is prepared by the above preparation method.

[0044] Application of the above-mentioned photo-crosslinked chitosan whisker composite liquid crystal gel material in the preparation of bone tissue repair materials.

[0045] The present invention has the following advantages and effects compared to the prior art:

[0046] (1) The photocrosslinked chitosan whisker composite liquid crystal gel material prepared by the present invention not only well maintains the liquid crystal properties of chitosan whiskers that mimic the natural bone extracellular matrix, but also gives the chitosan whisker liquid crystal morphological stability for practical applications.

[0047] (2) The chitosan whisker composite liquid crystal gel prepared by the present invention is cross-linked by ultraviolet-visible light irradiation, and the molding speed is relatively fast. The prepared composite liquid crystal gel material has excellent mechanical properties, cyclic compression properties and viscoelasticity that mimics natural bone cell extracellular matrix.

[0048] (3) The photocrosslinked chitin whisker composite liquid crystal gel prepared by the present invention has excellent cell affinity and osteogenic activity, can promote the adhesion, proliferation and osteogenic differentiation of stem cells, and has good application prospects in the field of bone tissue repair.

[0049] (4) The raw materials used in the present invention are widely available and low in cost. No toxic organic reagents are required in the preparation process, and the preparation method is simple and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1Graphs showing the time scan results of the CHWs / PEGDA liquid crystal suspension of Example 1 and the mCHWs / PEGDA liquid crystal suspension of Example 7 under a rotational rheometer; wherein A is a curve showing the change of storage modulus over time, and B is the time when the suspension is completely cross-linked.

[0051] Figure 2 The figures show the results of compression tests on different liquid crystal gels and photos of the actual objects before the tests. Among them, CHWs is the liquid crystal gel of Comparative Example 1, mCHWs is the liquid crystal gel of Comparative Example 2, PEG-CHWs is the liquid crystal gel of Example 1, and PEG-mCHWs is the liquid crystal gel of Example 7.

[0052] Figure 3 Polarizing microscope photographs of different products; among them, A is the hydrochloric acid-decomposed chitin whisker liquid crystal of Example 2, B is the maleic anhydride-treated chitin whisker liquid crystal of Example 8, C is the CHWs / PEGDA composite liquid crystal gel of Example 5, D is the mCHWs / PEGDA composite liquid crystal gel of Example 11, E is the CHWs liquid crystal gel in Comparative Example 1, and F is the mCHWs liquid crystal gel in Comparative Example 2.

[0053] Figure 4 Figures 1 and 2 show the spreading morphology of BMSC cells on different gel surfaces (A, B, and C) and the proliferation ability result diagram (D); wherein A is the PEGDA gel of the control group, B is the CHWs / PEGDA composite liquid crystal gel of Example 3, C is the mCHWs / PEGDA composite liquid crystal gel of Example 9, and the PEG in D is the PEGDA gel of the control group of Example 3, PEG-CHWs is the CHWs / PEGDA composite liquid crystal gel of Example 3, and PEG-mCHWs is the mCHWs / PEGDA composite liquid crystal gel of Example 9.

[0054] Figure 5 These are transmission electron microscope images and Zeta potential test result images of the hydrochloric acid-decomposed chitin whiskers of Example 4 and the maleic anhydride-treated chitin whiskers of Example 10; wherein A is the hydrochloric acid-decomposed chitin whiskers, and B is the maleic anhydride-treated chitin whiskers.

[0055] Figure 6 Graphs showing the results of circular dichroism testing of different liquid crystal gels; A is the CHWs / PEGDA composite liquid crystal gel of Example 6, and B is the mCHWs / PEGDA composite liquid crystal gel of Example 12. DETAILED DESCRIPTION

[0056] The present invention will be described in further detail below in conjunction with Examples and accompanying drawings, but embodiments of the present invention are not limited thereto. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art. Unless otherwise specified, the reagents and materials used in the present invention can be obtained commercially.

[0057] Example 1

[0058] (1) 10 g of chitosan powder (purchased from Aladdin Reagent Co., Ltd.) was added to a 2 mol / L hydrochloric acid solution and stirred to form a suspension. The suspension was heated to 90 °C under a nitrogen atmosphere and stirred for 2 h. After the reaction, the suspension was placed in a centrifuge tube for centrifugation to separate the solid and liquid. The centrifuge speed was 5000 rpm and the centrifugation time was 10 min. The precipitate was then placed in a 10000 D dialysis bag for dialysis. After 7 days of dialysis, it was freeze-dried and dried at a cold trap temperature of -48 °C and a vacuum degree of 0.1 Pa for 24 h. It was then ground to obtain hydrochloric acid-decomposed chitosan whiskers (CHWs).

[0059] (2) Deionized water was added as a solvent to the CHWs obtained in step (1) and stirred and dispersed to prepare an 8 wt% chitin whisker suspension, and the chitin whisker suspension was homogenized for 2.5 h using a cell disruptor with a power of 450 W to form hydrochloric acid-hydrolyzed chitin whisker liquid crystals.

[0060] (3) Adding a photocrosslinking monomer polyethylene glycol diacrylate (PEGDA) and a photocrosslinking initiator phenyl-2,4,6-trimethylbenzoyl lithium phosphite (LAP) to the hydrochloric acid-hydrolyzed chitosan whisker liquid crystal obtained in step (2) to prepare a CHWs / PEGDA suspension, wherein the concentration of the photocrosslinking monomer PEGDA in the suspension is 20 wt %, and the concentration of the photoinitiator LAP in the mixed suspension is 0.5 wt %.

[0061] (4) The CHWs / PEGDA composite suspension obtained in step (3) was placed under ultraviolet light with a wavelength of 350 nm for 180 seconds to obtain a CHWs / PEGDA composite liquid crystal gel material.

[0062] The CHWs / PEGDA suspension obtained in step (3) was tested for the time required for full crosslinking using a rotational rheometer. The suspension was subjected to a time sweep test under the test conditions of a frequency of 1 Hz and a strain of 1%. The results are shown in FIG. Figure 1 As shown in A, when the test time is 30s, 10mW / cm 2 The suspension was irradiated with UV light for 60 seconds, and the time of full cross-linking of the suspension was determined by comparing the change of storage modulus after UV light was turned on. Figure 1 As shown in Figure B, compared with the cross-linking time of CHWs cross-linked with genipin in Comparative Example 1, the cross-linking speed of the suspension in this embodiment is very fast, with a complete cross-linking time of 12.57±0.36 s. In Comparative Example 1, the cross-linking time of CHWs with genipin is as long as several days, which seriously limits the practical application of liquid crystal gels, especially directly limits the application of whisker liquid crystal gels as injectable bone tissue repair materials.

[0063] The actual photo of the CHWs / PEGDA composite liquid crystal gel material and the result of compression test on the CHWs / PEGDA composite liquid crystal gel material obtained in step (4) by a universal tensile machine are shown in FIG. Figure 2 Compared with the genipin cross-linked acid-decomposed chitosan whisker liquid crystal gel (CHWs group) in Comparative Example 1, the compression modulus of the CHWs / PEGDA composite liquid crystal gel obtained in Example 1 is significantly improved. Furthermore, the photos of the actual object show that the CHWs liquid crystal gel obtained in Comparative Example 1 is difficult to form and has poor morphological stability, while the CHWs / PEGDA composite liquid crystal gel obtained in Example 1 has a complete structure and a stable morphology.

[0064] Example 2

[0065] (1) 20 g of chitosan powder (purchased from Aladdin Reagent Co., Ltd.) was added to a 3 mol / L hydrochloric acid solution and stirred to form a suspension. The suspension was heated to 95 °C under a nitrogen atmosphere and stirred for 3 h. After the reaction, the suspension was placed in a centrifuge tube for centrifugation to separate the solid and liquid. The centrifuge speed was 5000 rpm and the centrifugation time was 12 min. The solid precipitate was then placed in a 10000 D dialysis bag for dialysis. After 12 days of dialysis, it was freeze-dried and dried at a cold trap temperature of -50 °C and a vacuum degree of 0.1 Pa for 24 h. It was then ground to obtain CHWs.

[0066] (2) Deionized water was added as a solvent to the CHWs obtained in step (1) and stirred and dispersed to prepare an 8.5 wt% chitin whisker suspension, and the chitin whisker suspension was homogenized for 2.5 h using a cell disruptor with a power of 500 W to form hydrochloric acid-hydrolyzed chitin whisker liquid crystals.

[0067] (3) Adding a photocrosslinking monomer, methacryloyl gelatin (GelMA), and a photocrosslinking initiator, riboflavin, to the hydrochloric acid-decomposed chitosan whisker liquid crystal obtained in step (2) to prepare a CHWs / GelMA suspension, wherein the concentration of the photocrosslinking monomer, GelMA, in the mixed suspension is 20 wt %, and the concentration of the photoinitiator, riboflavin, in the mixed suspension is 0.7 wt %.

[0068] (4) The CHWs / GelMA suspension obtained in step (3) was placed under ultraviolet visible light with a wavelength of 440 nm for 300 seconds to obtain a CHWs / GelMA composite liquid crystal gel material.

[0069] The hydrochloric acid-decomposed chitin whisker liquid crystal obtained in step (2) was placed under a polarizing microscope for observation. The results are as follows: Figure 3 As shown in Figure A, under a polarizing microscope, the acid-decomposed chitin whisker liquid crystal can be observed to have obvious birefringence and a distinct fingerprint texture.

[0070] Example 3

[0071] (1) 15 g of chitosan powder (purchased from Aladdin Reagent Co., Ltd.) was added to a 2.5 mol / L hydrochloric acid solution and stirred to form a suspension. The suspension was heated to 95°C under a nitrogen atmosphere and stirred for 4 h. After the reaction, the suspension was placed in a centrifuge tube and centrifuged at 4000 rpm for 10 min to separate the solid and liquid. The solid precipitate was then placed in a 10000 D dialysis bag for dialysis. After 10 days of dialysis, it was freeze-dried and dried at a cold trap temperature of -45°C and a vacuum degree of 0.1 Pa for 24 h. It was then ground to obtain CHWs.

[0072] (2) Deionized water was added as a solvent to the CHWs obtained in step (1) and stirred and dispersed to prepare an 8 wt% chitin whisker suspension, and the chitin whisker suspension was homogenized for 2.5 h using a cell disruptor with a power of 450 W to form hydrochloric acid-hydrolyzed chitin whisker liquid crystals.

[0073] (3) Adding the photocrosslinking monomer PEGDA and the photocrosslinking initiator LAP to the hydrochloric acid-hydrolyzed chitosan whisker liquid crystal obtained in step (2) to prepare a CHWs / PEGDA suspension, wherein the concentration of the photocrosslinking monomer PEGDA in the suspension is 30 wt %, and the concentration of the photoinitiator LAP in the suspension is 0.1 wt %.

[0074] (4) The CHWs / PEGDA suspension obtained in step (3) was placed under ultraviolet visible light with a wavelength of 350 nm for 300 seconds to obtain a CHWs / PEGDA composite liquid crystal gel material.

[0075] As a control group, a 30wt% PEGDA solution was prepared using deionized water as a solvent, and a photoinitiator LAP was added, wherein the LAP concentration was 0.1wt%, and the mixed solution was placed under blue visible light with a wavelength of 350nm for irradiation and cross-linking for 300s to obtain a PEG gel material. At the same time, a composite liquid crystal gel material was prepared according to the method in step (4). The above two gel materials were prepared into circular samples with a diameter of 10mm and a thickness of 1mm for bone marrow mesenchymal stem cell (BMSC) culture. After 48h of culture, BMSC were stained with DAPI and phalloidin, and the spreading area of BMSC on different materials was observed using a laser confocal microscope. After 7D of culture, the proliferation ability of BMSC on different materials was detected using a CCK-8 kit.

[0076] like Figure 4 As shown in A, B, and D, the cell proliferation ability on the surface of the composite liquid crystal gel material with added chitosan whiskers and maintaining the liquid crystal texture of chitosan whiskers is significantly better than that of the PEG gel material. At the same time, the surface of the composite liquid crystal gel material is more suitable for cell adhesion and spreading, and the cell spreading area is larger in the same time.

[0077] Example 4

[0078] (1) 5 g of chitosan powder (purchased from Aladdin Reagent Co., Ltd.) was added to a 1.5 mol / L hydrochloric acid solution and stirred to form a suspension. The suspension was heated to 90 °C under a nitrogen atmosphere and stirred for 2 h. After the reaction, the suspension was placed in a centrifuge tube for centrifugation to separate the solid and liquid. The centrifuge speed was 7000 rpm and the centrifugation time was 15 min. The solid precipitate was then placed in a 10000 D dialysis bag for dialysis. After 10 days of dialysis, it was freeze-dried and dried at a cold trap temperature of -45 °C and a vacuum degree of 0.3 Pa for 24 h. It was then ground to obtain CHWs.

[0079] (2) adding the CHWs obtained in step (1) to deionized water as a solvent and stirring and dispersing the CHWs to prepare an 8.5 wt% chitin whisker suspension, and homogenizing the chitin whisker suspension for 2.5 h using a cell disruptor with a power of 500 W to form hydrochloric acid-hydrolyzed chitin whisker liquid crystals.

[0080] (3) Adding a photocrosslinking monomer GelMA and a photocrosslinking initiator 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I2959) to the hydrochloric acid-hydrolyzed chitin whisker liquid crystal obtained in step (2) to prepare a CHWs / GelMA suspension, wherein the concentration of the photocrosslinking monomer GelMA in the suspension is 30 wt %, and the concentration of the photoinitiator I2959 in the suspension is 0.5 wt %.

[0081] (4) The CHWs / GelMA suspension obtained in step (3) was placed under ultraviolet light with a wavelength of 380 nm for 120 seconds to obtain a CHWs / GelMA composite liquid crystal gel material.

[0082] The morphology of the CHWs prepared in step (1) was observed by transmission electron microscopy (TEM), and the Zeta potential of the CHWs was tested. The results are as follows: Figure 5 As shown in A, the chitosan whiskers prepared in this step have a needle-rod structure, a length between 150-350 nm, a diameter between 15-30 nm, and a Zeta potential value of +37.6 mV.

[0083] Example 5

[0084] (1) 15 g of chitosan powder (purchased from Aladdin Reagent Co., Ltd.) was added to a 3 mol / L hydrochloric acid solution and stirred to form a suspension. The suspension was heated to 90 °C under a nitrogen atmosphere and stirred for 3 h. After the reaction, the suspension was placed in a centrifuge tube for centrifugation to separate the solid and liquid. The centrifuge speed was 6000 rpm and the centrifugation time was 15 min. The solid precipitate was then placed in a 10000 D dialysis bag for dialysis. After 10 days of dialysis, it was freeze-dried and dried for 24 h at a cold trap temperature of -48 °C and a vacuum degree of 0.5 Pa. It was then ground to obtain CHWs.

[0085] (2) Deionized water was added as a solvent to the CHWs obtained in step (1) and stirred and dispersed to prepare an 8 wt % chitin whisker suspension, and the chitin whisker suspension was homogenized for 3 h using a cell disruptor with a power of 500 W to form hydrochloric acid-hydrolyzed chitin whisker liquid crystals.

[0086] (3) Adding the photocrosslinking monomer PEGDA and the photocrosslinking initiator LAP to the hydrochloric acid-decomposed chitosan whisker liquid crystal obtained in step (2) to prepare a CHWs / PEGDA suspension, wherein the concentration of the photocrosslinking monomer PEGDA in the suspension is 30 wt %, and the concentration of the photoinitiator LAP in the suspension is 0.2 wt %.

[0087] (4) The CHWs / PEGDA suspension obtained in step (3) was placed under ultraviolet light with a wavelength of 350 nm for 180 seconds to obtain a CHWs / PEGDA composite liquid crystal gel material.

[0088] The CHWs / PEGDA composite liquid crystal gel material obtained in step (4) was placed under a polarizing microscope for observation. Figure 3As shown in Figure C, a fingerprint-like liquid crystal texture can be observed, indicating that the CHWs / PEGDA composite liquid crystal gel material retains the anisotropic structure of the chitin whisker liquid crystal.

[0089] Example 6

[0090] (1) 10 g of chitosan powder (purchased from Aladdin Reagent Co., Ltd.) was added to a 2 mol / L hydrochloric acid solution and stirred to form a suspension. The suspension was heated to 90 °C under a nitrogen atmosphere and stirred for 2 h. After the reaction, the suspension was placed in a centrifuge tube for centrifugation to separate the solid and liquid. The centrifuge speed was 8000 rpm and the centrifugation time was 12 min. The solid precipitate was then placed in a 10000 D dialysis bag for dialysis. After 7 days of dialysis, it was freeze-dried and dried for 24 h at a cold trap temperature of -45 °C and a vacuum degree of 0.1 Pa. It was then ground to obtain CHWs.

[0091] (2) Deionized water was added as a solvent to the CHWs obtained in step (1) and stirred and dispersed to prepare an 8 wt% chitin whisker suspension, and the chitin whisker suspension was homogenized for 2.5 h using a cell disruptor with a power of 450 W to form hydrochloric acid-hydrolyzed chitin whisker liquid crystals.

[0092] (3) Adding the photocrosslinking monomer PEGDA and the photocrosslinking initiator I2959 to the hydrochloric acid-decomposed chitosan whisker liquid crystal obtained in step (2) to prepare a CHWs / PEGDA suspension, wherein the concentration of the photocrosslinking monomer PEGDA in the suspension is 30 wt %, and the concentration of the photoinitiator I2959 in the suspension is 0.5 wt %.

[0093] (4) The CHWs / PEGDA suspension obtained in step (3) was placed under ultraviolet light with a wavelength of 320 nm for 180 seconds to obtain a CHWs / PEGDA composite liquid crystal gel material.

[0094] The composite liquid crystal gel material prepared in step (4) was tested using a circular dichroism spectrometer at a wavelength of 250-800 nm. Figure 6 As shown in Figure A, the prepared composite liquid crystal gel material has obvious circular dichroism, indicating that the composite liquid crystal gel material has obvious chirality and the liquid crystal texture of the composite liquid crystal gel material is a chiral nematic liquid crystal texture.

[0095] Example 7

[0096] (1) 150 g of maleic anhydride solid was weighed and heated to melt at 80 °C. Then, 10 g of chitosan powder (purchased from Aladdin Reagent Co., Ltd.) was added to the maleic anhydride liquid and stirred to form a suspension. The suspension was heated to 110 °C under a nitrogen atmosphere and stirred for 5 h. After the reaction, the suspension was placed in a centrifuge tube and centrifuged to separate the solid and liquid. The centrifuge speed was 8000 rpm and the centrifugation time was 15 min. After the supernatant was poured out, deionized water was added and the centrifugation operation was repeated until the supernatant was neutral. The mixture was freeze-dried and dried at a cold trap temperature of -48 °C and a vacuum degree of 0.1 Pa for 24 h. The mixture was then ground to obtain maleic anhydride chitosan whiskers (mCHWs).

[0097] (2) Deionized water was added as a solvent to the mCHWs obtained in step (1) and stirred and dispersed to prepare an 8 wt % chitosan whisker suspension, and the chitosan whisker suspension was homogenized for 2.5 h using a cell disruptor with a power of 450 W to form maleic anhydride chitosan whisker liquid crystals.

[0098] (3) Adding photocrosslinking PEGDA and photocrosslinking initiator LAP to the maleic anhydride chitosan whisker liquid crystal obtained in step (2) to prepare an mCHWs / PEGDA suspension, wherein the concentration of the photocrosslinking monomer PEGDA in the suspension is 30 wt %, and the concentration of the photoinitiator LAP in the suspension is 0.1 wt %.

[0099] (4) The mCHWs / PEGDA suspension obtained in step (3) was placed under ultraviolet light with a wavelength of 350 nm for 180 seconds to obtain a mCHWs / PEGDA composite liquid crystal gel material.

[0100] The mCHWs / PEGDA suspension obtained in step (3) was tested for the time required for full crosslinking using a rotational rheometer. The suspension was subjected to a time sweep test under the conditions of a frequency of 1 Hz and a strain of 1%. The results are shown in FIG. Figure 1 As shown in A, when the test time is 30s, 10mW / cm 2 The suspension was irradiated with UV light for 60 seconds, and the time of full cross-linking of the suspension was determined by comparing the change of storage modulus after UV light was turned on. Figure 1 As shown in Figure B, compared with the cross-linking time of mCHWs cross-linked with genipin in Comparative Example 2, the cross-linking speed of the suspension in this embodiment is very fast, with a complete cross-linking time of 12.36±0.27 s. In Comparative Example 2, the time for cross-linking mCHWs with genipin is as long as several days, which seriously limits the practical application of liquid crystal gels, especially directly limits the application of whisker liquid crystal gels as injectable bone tissue repair materials.

[0101] The actual photo of the mCHWs / PEGDA composite liquid crystal gel material and the result of the compression test of the mCHWs / PEGDA composite liquid crystal gel material obtained in step (4) by a universal tensile machine are shown in FIG. Figure 2 Compared with the maleic anhydride chitosan whisker liquid crystal gel (mCHWs group) in Comparative Example 2, the compression modulus of the mCHWs / PEGDA composite liquid crystal gel is significantly improved. At the same time, it can be seen from the actual photos that the mCHWs liquid crystal gel is difficult to form and has poor morphological stability, while the mCHWs / PEGDA composite liquid crystal gel has a complete structure and stable morphology.

[0102] Example 8

[0103] (1) 100 g of maleic anhydride solid was weighed and heated to melt at 60 °C. Then, 5 g of chitin powder (purchased from Aladdin Reagent Co., Ltd.) was added to the maleic anhydride liquid and stirred to form a suspension. The suspension was heated to 125 °C under a nitrogen atmosphere and stirred for 6 h. After the reaction, the suspension was placed in a centrifuge tube and centrifuged to separate the solid and liquid. The centrifuge speed was 5000 rpm and the centrifugation time was 12 min. After the supernatant was poured out, deionized water was added and the centrifugation operation was repeated until the supernatant was neutral. The mixture was freeze-dried and dried at a cold trap temperature of -50 °C and a vacuum degree of 0.1 Pa for 24 h. Then, the mCHWs were ground to obtain.

[0104] (2) Deionized water was added as a solvent to the mCHWs obtained in step (1) and stirred and dispersed to prepare an 8.5 wt% chitin whisker suspension, and the chitin whisker suspension was homogenized for 2.5 h using a cell disruptor with a power of 450 W to form maleic anhydride chitin whisker liquid crystals.

[0105] (3) Photocrosslinked methacryloyl hyaluronic acid (HAMA) and photocrosslinking initiator riboflavin are added to the maleic anhydride chitosan whisker liquid crystal obtained in step (2) to prepare an mCHWs / HAMA suspension, wherein the concentration of the photocrosslinked monomer HAMA in the suspension is 20 wt %, and the concentration of the photoinitiator riboflavin in the suspension is 0.5 wt %.

[0106] (4) The mCHWs / HAMA suspension obtained in step (3) was placed under ultraviolet-visible light with a wavelength of 450 nm for 300 seconds for cross-linking, thereby obtaining a mCHWs / HAMA composite liquid crystal gel material.

[0107] The maleic anhydride chitosan whisker liquid crystal obtained in step (2) was placed under a polarizing microscope for observation. Figure 3As shown in Figure B, under a polarizing microscope, the maleic anhydride chitosan whisker liquid crystal can be observed to have obvious birefringence and a distinct fingerprint texture.

[0108] Example 9

[0109] (1) Weigh 100 g of maleic anhydride solid and heat it at 60 °C to melt it. Then, add 5 g of chitin powder (purchased from Aladdin Reagent Co., Ltd.) to the maleic anhydride liquid and stir it evenly to form a suspension. Under a nitrogen atmosphere, heat the suspension to 135 °C and stir it for 3 h. After the reaction, place the suspension in a centrifuge tube and centrifuge it to separate the solid and liquid. The centrifuge speed is 4000 rpm and the centrifugation time is 10 min. After the supernatant is poured out, deionized water is added and the centrifugation operation is repeated until the supernatant is neutral. Then, freeze-dry it and dry it at a cold trap temperature of -45 °C and a vacuum degree of 0.1 Pa for 24 h. Then grind it to obtain mCHWs.

[0110] (2) Deionized water was added as a solvent to the mCHWs obtained in step (1) and stirred and dispersed to prepare an 8 wt % chitosan whisker suspension, and the chitosan whisker suspension was homogenized for 2.5 h using a cell disruptor with a power of 450 W to form maleic anhydride chitosan whisker liquid crystals.

[0111] (3) Adding photocrosslinking PEGDA and photocrosslinking initiator LAP to the maleic anhydride chitosan whisker liquid crystal obtained in step (2) to prepare an mCHWs / PEGDA suspension, wherein the concentration of the photocrosslinking monomer PEGDA in the suspension is 30 wt %, and the concentration of the photoinitiator LAP in the suspension is 0.1 wt %.

[0112] (4) The mCHWs / PEGDA suspension obtained in step (3) was placed under ultraviolet light with a wavelength of 350 nm for irradiation and cross-linking for 300 seconds, thereby obtaining a mCHWs / PEGDA composite liquid crystal gel material.

[0113] According to the preparation method of step (4), the composite liquid crystal gel material was prepared into a circular sample with a diameter of 10 mm and a thickness of 1 mm for culturing bone marrow mesenchymal stem cells (BMSCs). After 48 hours of culture, the BMSCs were stained with DAPI and phalloidin, and the spreading area of the BMSCs on the different materials was observed using a laser confocal microscope. After 7 days of culture, the proliferation ability of the BMSCs on the different materials was detected using a CCK-8 kit.

[0114] like Figure 4As shown in A, C, and D, the cell proliferation ability of the composite liquid crystal gel material with added chitosan whiskers and maintained chitosan whisker liquid crystal texture is significantly better than that of the PEG gel material. The introduced carboxyl groups are less toxic to cells. At the same time, the surface of the composite liquid crystal gel material is more suitable for cell adhesion and spreading, and the cell spreading area is larger in the same time.

[0115] Example 10

[0116] (1) 150 g of maleic anhydride solid was weighed and heated to melt at 60 °C. Then, 10 g of chitin powder (purchased from Aladdin Reagent Co., Ltd.) was added to the maleic anhydride liquid and stirred to form a suspension. Under a nitrogen atmosphere, the suspension was heated to 105 °C and stirred for 5 h. After the reaction, the suspension was placed in a centrifuge tube and centrifuged to separate the solid and liquid. The centrifuge speed was 9000 rpm and the centrifugation time was 15 min. After the supernatant was poured out, deionized water was added and the centrifugation operation was repeated until the supernatant was neutral. It was then freeze-dried and dried at a cold trap temperature of -45 °C and a vacuum degree of 0.1 Pa for 24 h. Then, mCHWs were ground to obtain.

[0117] (2) Deionized water was added as a solvent to the mCHWs obtained in step (1) and stirred and dispersed to prepare an 8.5 wt% chitin whisker suspension, and the chitin whisker suspension was homogenized for 2.5 h using a cell disruptor with a power of 500 W to form maleic anhydride chitin whisker liquid crystals.

[0118] (3) Adding a photocrosslinking monomer HAMA and a photocrosslinking initiator I2959 to the maleic anhydride chitosan whisker liquid crystal obtained in step (2) to prepare an mCHWs / HAMA suspension, wherein the concentration of the photocrosslinking monomer HAMA in the suspension is 30 wt %, and the concentration of the photoinitiator I2959 in the suspension is 0.5 wt %.

[0119] (4) The mCHWs / HAMA suspension obtained in step (3) was placed under ultraviolet light with a wavelength of 380 nm for 120 seconds to obtain a mCHWs / HAMA composite liquid crystal gel material.

[0120] The morphology of the mCHWs prepared in step (1) was observed by transmission electron microscopy (TEM), and the Zeta potential of the mCHWs was tested. Figure 5 As shown in B, the chitosan whiskers prepared in this step have a needle-rod structure, with a length of 200-450 nm, a diameter of 15-40 nm, and a Zeta potential value of -37.3 mV, indicating that carboxyl groups have been successfully introduced into the chitosan whiskers.

[0121] Example 11

[0122] (1) 150 g of maleic anhydride solid was weighed and heated to melt at 60 °C, and then 10 g of chitin powder (purchased from Aladdin Reagent Co., Ltd.) was added thereto and stirred to form a suspension. The suspension was heated to 125 °C under a nitrogen atmosphere and stirred for 5 h. After the reaction, the suspension was placed in a centrifuge tube and centrifuged to separate the solid and liquid. The centrifuge speed was 5000 rpm and the centrifugation time was 20 min. After the supernatant was poured out, deionized water was added and the centrifugation operation was repeated until the supernatant was neutral. It was then freeze-dried and dried at a cold trap temperature of -48 °C and a vacuum degree of 0.1 Pa for 24 h. Then, mCHWs were ground to obtain.

[0123] (2) Deionized water was added as a solvent to the mCHWs obtained in step (1) and stirred and dispersed to prepare an 8.5 wt% chitin whisker suspension, and the chitin whisker suspension was homogenized for 2.5 h using a cell disruptor with a power of 500 W to form maleic anhydride chitin whisker liquid crystals.

[0124] (3) Adding the photocrosslinking monomer PEGDA and the photocrosslinking initiator LAP to the maleic anhydride chitosan whisker liquid crystal obtained in step (2) to prepare an mCHWs / PEGDA suspension, wherein the concentration of the photocrosslinking monomer PEGDA in the mixed suspension is 30 wt %, and the concentration of the photoinitiator LAP in the mixed suspension is 0.1 wt %.

[0125] (4) The mCHWs / PEGDA suspension obtained in step (3) was placed under ultraviolet light with a wavelength of 380 nm for 180 seconds to obtain a mCHWs / PEGDA composite liquid crystal gel material.

[0126] The mCHWs / PEGDA composite liquid crystal gel material obtained in step (4) was placed under a polarizing microscope for observation. Figure 3 Figure D shows the mCHWs / PEGDA composite liquid crystal gel. A fingerprint-like liquid crystal texture can be observed in the composite liquid crystal gel under a polarizing microscope, indicating that the mCHWs / PEGDA composite liquid crystal gel retains the anisotropic structure of the chitin whisker liquid crystal.

[0127] Example 12

[0128] (1) 100 g of maleic anhydride solid was weighed and heated to melt at 70 °C. Then, 10 g of chitin powder (purchased from Aladdin Reagent Co., Ltd.) was added to the maleic anhydride liquid and stirred to form a suspension. The suspension was heated to 120 °C under a nitrogen atmosphere and stirred for 6 h. After the reaction, the suspension was placed in a centrifuge tube and centrifuged to separate the solid and liquid. The centrifuge speed was 5000 rpm and the centrifugation time was 20 min. After the supernatant was poured out, deionized water was added and the centrifugation operation was repeated until the supernatant was neutral. The mixture was freeze-dried and dried at a cold trap temperature of -45 °C and a vacuum degree of 0.1 Pa for 24 h. Then, the mCHWs were ground to obtain.

[0129] (2) Deionized water was added as a solvent to the mCHWs obtained in step (1) and stirred and dispersed to prepare an 8 wt % chitosan whisker suspension, and the chitosan whisker suspension was homogenized for 3 h using a cell disruptor with a power of 500 W to form maleic anhydride chitosan whisker liquid crystals.

[0130] (3) Adding the photocrosslinking monomer PEGDA and the photocrosslinking initiator I2959 to the maleic anhydride chitosan whisker liquid crystal obtained in step (2) to prepare an mCHWs / PEGDA suspension, wherein the concentration of the photocrosslinking monomer PEGDA in the suspension is 30 wt %, and the concentration of the photoinitiator LAP in the suspension is 0.5 wt %.

[0131] (4) The mCHWs / PEGDA suspension obtained in step (3) was placed under ultraviolet light with a wavelength of 380 nm for 200 seconds to obtain a mCHWs / PEGDA composite liquid crystal gel material.

[0132] The composite liquid crystal gel material prepared in step (4) was tested by circular dichroism spectrometry at a wavelength of 250-800 nm. Figure 6 As shown in B, the prepared composite liquid crystal gel material has circular dichroism, indicating that the composite liquid crystal gel material has chirality and the liquid crystal texture of the composite liquid crystal gel material is a chiral nematic liquid crystal texture.

[0133] Comparative Example 1

[0134] (1) 10 g of chitosan powder (purchased from Aladdin Reagent Co., Ltd.) was added to a 2 mol / L hydrochloric acid solution and stirred to form a suspension. The suspension was heated to 90 °C under a nitrogen atmosphere and stirred for 2 h. After the reaction, the suspension was placed in a centrifuge tube for centrifugation to separate the solid and liquid. The centrifuge speed was 5000 rpm and the centrifugation time was 15 min. The solid precipitate was then placed in a 10000 D dialysis bag for dialysis. After 7 days of dialysis, it was freeze-dried and dried for 24 h at a cold trap temperature of -48 °C and a vacuum degree of 0.1 Pa. It was then ground to obtain CHWs.

[0135] (2) Deionized water was added as a solvent to the CHWs obtained in step (1) and stirred and dispersed to prepare an 8 wt% chitin whisker suspension, and the chitin whisker suspension was homogenized for 2.5 h using a cell disruptor with a power of 450 W to form hydrochloric acid-hydrolyzed chitin whisker liquid crystals.

[0136] (3) Adding the crosslinking agent genipin to the hydrochloric acid-hydrolyzed chitin whisker liquid crystal obtained in step (2) to prepare a chitin whisker / genipin suspension, wherein the concentration of genipin in the mixed suspension is 0.3 wt %. The suspension is stirred evenly and then placed in a constant temperature water bath at 37° C. for 5 days for a crosslinking reaction, thereby obtaining a CHWs liquid crystal gel material.

[0137] The CHWs liquid crystal gel material prepared in step (3) was placed under a polarizing microscope for observation. Figure 3 As shown in E, the fingerprint-like liquid crystal texture of CHWs liquid crystal gel can be observed, indicating that it retains the anisotropic structure of chitin whisker liquid crystal. The compression performance of CHWs liquid crystal gel material and the actual photo before compression are shown in Figure 2 As shown (CHWs group), the compression modulus of the gel material cannot be tested due to its poor mechanical properties, and it can also be seen from the actual photos that the CHWs liquid crystal gel does not have the morphological stability for practical applications.

[0138] Comparative Example 2

[0139] (1) 150 g of maleic anhydride solid was taken and heated and melted at 80 °C. Then, 10 g of chitin powder (purchased from Aladdin Reagent Co., Ltd.) was added to the maleic anhydride liquid and stirred to form a suspension. Under a nitrogen atmosphere, the suspension was heated to 110 °C and stirred for 5 h. After the reaction, the suspension was placed in a centrifuge tube and centrifuged to separate the solid and liquid. The centrifuge speed was 8000 rpm and the centrifugation time was 15 min. After the supernatant was poured out, deionized water was added and the centrifugation operation was repeated until the supernatant was neutral. It was then freeze-dried and dried at a cold trap temperature of -48 °C and a vacuum degree of 0.1 Pa for 24 h. Then, mCHWs were ground to obtain.

[0140] (2) Deionized water was added as a solvent to the mCHWs obtained in step (1) and stirred and dispersed to prepare an 8 wt % chitosan whisker suspension, and the chitosan whisker suspension was homogenized for 2.5 h using a cell disruptor with a power of 450 W to form maleic anhydride chitosan whisker liquid crystals.

[0141] (3) The crosslinking agent genipin was added to the maleic anhydride chitin whisker liquid crystal obtained in step (2) to prepare a chitin whisker / genipin suspension, wherein the concentration of genipin in the mixed suspension was 0.3 wt %. The suspension was stirred evenly and then placed in a constant temperature water bath at 37° C. for 5 days for a crosslinking reaction, thereby obtaining a mCHWs liquid crystal gel material.

[0142] The mCHWs liquid crystal gel prepared in step (3) was placed under a polarizing microscope for observation. Figure 3 As shown in Figure F, the fingerprint-like liquid crystal texture of the mCHWs liquid crystal gel can be observed, indicating that it retains the anisotropic structure of the mCHWs liquid crystal. The compression properties of the mCHWs liquid crystal gel material and the actual photo are shown in Figure 3. Figure 2 As shown (mCHWs group), the compression modulus of the gel material cannot be tested due to its poor mechanical properties, and it can also be seen from the actual photos that the mCHWs liquid crystal gel does not have the morphological stability for practical applications.

[0143] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing a photocrosslinked chitosan whisker composite liquid crystal gel material, characterized in that The following steps are involved: (1) preparing chitosan whiskers into a chitosan whisker suspension, and ultrasonically treating the chitosan whisker suspension to obtain chitosan whisker liquid crystals; (2) adding a photocrosslinking monomer and a photocrosslinking initiator to the chitosan whisker liquid crystal obtained in step (1) to obtain a mixed suspension; (3) cross-linking the mixed suspension obtained in step (2) under light irradiation to obtain a photo-cross-linked chitosan whisker composite liquid crystal gel material; The chitosan whiskers described in step (1) are at least one of hydrochloric acid-decomposed chitosan whiskers and maleic anhydride-decomposed chitosan whiskers; The photocrosslinking monomer in step (2) is at least one of polyethylene glycol diacrylate, methacrylated gelatin and methacrylated hyaluronic acid; The photocrosslinking initiator in step (2) is at least one of phenyl-2,4,6-trimethylbenzoyl lithium phosphite, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone and riboflavin.

2. The method for preparing the photocrosslinked chitosan whisker composite liquid crystal gel material according to claim 1, characterized in that: The hydrochloric acid-decomposed chitin whiskers are prepared by the following steps: uniformly dispersing chitin powder in a hydrochloric acid solution and performing an acid decomposition reaction under a nitrogen atmosphere; after the reaction is completed, solid-liquid separation is performed, the obtained solid is dialyzed, and the dialyzed product is dried to obtain the hydrochloric acid-decomposed chitin whiskers; The maleic anhydride chitosan whiskers are prepared by the following steps: heating and dissolving maleic anhydride to obtain maleic anhydride liquid, then adding chitosan powder and stirring evenly to form a suspension, and performing a maleic anhydride reaction under a nitrogen atmosphere; after the reaction is completed, centrifuging to separate the solid and liquid, pouring out the supernatant, adding deionized water, and repeating the centrifugation operation until the supernatant is neutral, and drying the separated solid to obtain the maleic anhydride chitosan whiskers.

3. The method for preparing the photo-crosslinked chitosan whisker composite liquid crystal gel material according to claim 2, characterized in that: The concentration of the hydrochloric acid solution is 1 to 10 mol / L; The conditions of the acid hydrolysis reaction are: reacting at a reaction temperature of 80 to 95° C. for 1 to 6 hours; The dialysis is performed in a dialysis bag with a molecular weight cut-off of 8000 to 20000 D for 7 to 14 days; The heating is heating to 60-80°C; The amount of chitosan powder is calculated based on the mass ratio of maleic anhydride to chitosan powder (100-150): (5-20). The conditions of the maleic anhydride reaction are: reacting at a reaction temperature of 100 to 135° C. for 2 to 6 hours; The solid-liquid separation method is centrifugation; The drying is freeze drying.

4. The method for preparing the photo-crosslinked chitosan whisker composite liquid crystal gel material according to claim 3, characterized in that: The concentration of the hydrochloric acid solution is 1.5 to 3 mol / L; The conditions of the acid hydrolysis reaction are: reacting at a reaction temperature of 90°C for 2 to 4 hours; The dialysis is performed in a dialysis bag with a molecular weight cut-off of 10,000 D for 7 to 12 days; The amount of chitosan powder is calculated based on the mass ratio of maleic anhydride to chitosan powder (100-150): (5-10). The conditions of the maleic anhydride reaction are: reacting at a reaction temperature of 105 to 135° C. for 3 to 6 hours; The centrifugal conditions are as follows: centrifugation in a centrifuge at a speed of 4000-9000 rpm for 10-20 min; The freeze-drying conditions are drying for 24 hours at a cold trap temperature of -45 to 50°C and a vacuum degree of 0.1 to 0.5 Pa.

5. The method for preparing the photo-crosslinked chitosan whisker composite liquid crystal gel material according to claim 1, characterized in that: The chitin whiskers described in step (1) have a length of 100 to 1000 nm and a diameter of 10 to 50 nm; The concentration of the chitosan whisker suspension in step (1) is 5 to 15 wt%; The mass ratio of the chitin whiskers in step (1) to the photocrosslinking monomer in step (2) is chitin whiskers: photocrosslinking monomer = 1 to 3:5; The concentration of the photocrosslinking monomer in step (2) in the mixed suspension is 5 to 30 wt%; The concentration of the photocrosslinking initiator in step (2) in the mixed suspension is 0.1 to 1 wt %; The light in step (3) is ultraviolet light or visible light; The irradiation time of the light irradiation in step (3) is 60 to 600 s.

6. The method for preparing the photo-crosslinked chitosan whisker composite liquid crystal gel material according to claim 5, characterized in that: The chitin whiskers described in step (1) have a length of 150 to 350 nm and a diameter of 15 to 30 nm; The concentration of the chitosan whisker suspension in step (1) is 8 to 12 wt %; The mass ratio of the chitin whiskers in step (1) to the photocrosslinking monomer in step (2) is chitin whiskers: photocrosslinking monomer = 1.3 to 2.1:5; The concentration of the photocrosslinking monomer in step (2) in the mixed suspension is 20-30 wt%; The concentration of the photocrosslinking initiator in step (2) in the mixed suspension is 0.1 to 0.7 wt %; The wavelength of the light in step (3) is 300 to 500 nm; The irradiation time of the light irradiation in step (3) is 120 to 300 s.

7. The method for preparing the photo-crosslinked chitosan whisker composite liquid crystal gel material according to claim 1, characterized in that: The chitosan whisker suspension in step (1) is prepared by adding chitosan whiskers into deionized water and stirring and dispersing them; The ultrasonic treatment conditions described in step (1) are: ultrasonic treatment at an ultrasonic power of 300 to 600 W for 1 to 3 hours.

8. A photo-crosslinked chitosan whisker composite liquid crystal gel material, characterized by: The material is obtained by the preparation method of the photo-crosslinked chitosan whisker composite liquid crystal gel material according to any one of claims 1 to 7.

9. Use of the photo-crosslinked chitosan whisker composite liquid crystal gel material according to claim 8 in the preparation of bone tissue repair materials.

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