阅读说明：本技术 一种可光固化的化合物及其制备方法和应用 (Photocurable compound and preparation method and application thereof ) 是由 周旋 周忠娇 李娜娜 李喜露 李昕 于 2021-01-28 设计创作，主要内容包括：本发明提供了一种可光固化的化合物,所述化合物的基本骨架为明胶,且在所述明胶上接枝有SbQ,所述SbQ为N-甲基-4-(对甲酰苯乙烯基)吡啶甲基硫酸盐。该化合物以明胶为基本骨架,接枝上苯乙烯吡啶甲基硫酸盐(SbQ)制备得到,其安全无毒,具有良好的生物相容性和生物降解性；化合物中的SbQ基团为光敏性基团,在不依赖外源性光引发剂的情况下,经紫外光或蓝光的照射即可发生聚合交联,形成水凝胶。本发明还提供了上述化合物的制备方法以及该可光固化的化合物在3D生物打印中的应用。(The invention provides a light-curable compound, wherein the basic skeleton of the compound is gelatin, and SbQ is grafted on the gelatin, and the SbQ is N-methyl-4- (p-formylstyryl) pyridine methyl sulfate. The compound is prepared by taking gelatin as a basic skeleton and grafting styrene pyridine methyl sulfate (SbQ), is safe and nontoxic, and has good biocompatibility and biodegradability; SbQ group in the compound is photosensitive group, and can generate polymerization crosslinking through the irradiation of ultraviolet light or blue light under the condition of not depending on exogenous photoinitiator, thereby forming hydrogel. The invention also provides a preparation method of the compound and application of the light-curable compound in 3D biological printing.)

1. A photocurable compound characterized in that the basic skeleton of the compound is gelatin, and SbQ is grafted onto the gelatin, wherein SbQ is N-methyl-4- (p-formylstyryl) pyridylmethyl sulfate.

2. The compound of claim 1, wherein the compound is prepared from 5-15 parts by weight of gelatin and 0.5-1.5 parts by weight of SbQ graft.

3. The compound of claim 1, wherein the hemiacetal group in SbQ molecule is covalently bonded to a gelatin molecule by condensation dehydration reaction with a hydroxyl group in the gelatin molecule.

4. A process for the preparation of a compound according to claim 1, comprising the steps of:

s1.SbQ synthesis: taking 25-60 parts of terephthalaldehyde, 9-19 parts of gamma-methylpyridine, 25-30 parts of acetic anhydride and 10-15 parts of acetic acid according to parts by weight, fully mixing, and heating and refluxing for 6-8 hours at 100 ℃; adding 300 portions of 1mol/L hydrochloric acid, standing for 1-2 hours at room temperature, and filtering unreacted precipitates; heating the filtrate to 30-40 deg.C, extracting with benzene to remove terephthalaldehyde, adding 1mol/L sodium hydroxide solution to adjust to neutrality; filtering, collecting yellow precipitate, washing with pure water, air drying, heating to 70-80 deg.C with 30-40 parts of ethyl acetate for dissolving, and filtering to remove insoluble substances; adding 50 parts of dimethyl sulfate into the filtrate, standing overnight, filtering, washing and drying by using methanol and acetone, and collecting insoluble substances to obtain SbQ;

s2, synthesis of Gelatin-SbQ: taking 5-15 parts of gelatin, adding 100-300 parts of distilled water, magnetically stirring, heating and dissolving until the gelatin is clear and transparent, adding 0.5-1.5 parts of SbQ, and magnetically stirring to react at 40-80 ℃ for 12-24 hours; adding 11mol/L sodium hydroxide solution to adjust the pH value to 6-7, washing and drying by using methanol and acetone, and collecting insoluble substances to obtain Gelatin-SbQ.

5. The method according to claim 1, wherein the reactions of S1 and S2 are performed in a light-shielding environment.

6. The process according to claim 1, wherein the gelatin is type A gelatin having a BLOOM value corresponding to 300g jelly strength.

7. A photocurable compound for use in 3D printing, characterized in that the photocurable compound according to any one of claims 1-3 is used, and the photocurable compound prepared by the preparation method according to any one of claims 4-6 is used.

Technical Field

The invention relates to the technical field of 3D printing ink preparation, in particular to a light-curable compound and a preparation method and application thereof.

Background

Due to its good biosafety, gelatin is widely used in tissue engineering. However, gelatin molecules do not have a photo-curing function, and when the gelatin molecules are applied to 3D printing bio-ink, if photo-curing is to be achieved, modification is generally required, such as methacrylated gelatin (GelMA), and then an exogenous photo-curing initiator, such as I2959 (2-hydroxy-4' - (2-hydroxyethoxy) -2-methyl propiophenone) or LAP (lithium phenyl-2, 4, 6-trimethylbenzoylphosphonate), is added, and then polymerization crosslinking reaction can occur under the irradiation of ultraviolet light or blue light.

Some high molecular compounds obtain the photocuring performance by grafting photocuring molecules, but the biological safety of the substances is poor.

The Chinese patent with the publication number of CN107041969A provides a gelatin-based inverted colloidal crystal hydrogel three-dimensional bracket, wherein the gelatin-based inverted colloidal crystal hydrogel three-dimensional bracket is made of methacrylamide gelatin, and the gelatin-based inverted colloidal crystal hydrogel made of the methacrylamide gelatin has an inverse opal structure. The gelatin-based inverted colloidal crystal hydrogel three-dimensional scaffold is prepared by the following preparation method: (1) preparing methacrylamide gelatin; (2) preparing the gelatin-based inverted colloidal crystal hydrogel three-dimensional scaffold. However, the gelatin-based inverted colloidal crystal hydrogel three-dimensional scaffold still needs to be subjected to photocuring by additionally adding an exogenous photocuring initiator.

Therefore, it is a technical problem to be solved by those skilled in the art to provide a compound which can be polymerized by photo-curing under ultraviolet light and has good biological safety.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a light-curable compound which is prepared by taking gelatin as a basic skeleton and grafting styrene pyridine methyl sulfate (SbQ), is safe and nontoxic and has good biocompatibility and biodegradability; SbQ group contained in the compound is photosensitive group, and can generate polymerization crosslinking through the irradiation of ultraviolet light or blue light under the condition of not depending on exogenous photoinitiator, thereby forming hydrogel.

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

a photocurable compound, the basic skeleton of which is gelatin, and SbQ is grafted onto the gelatin, wherein SbQ is N-methyl-4- (p-formylstyryl) pyridylmethyl sulfate.

As further description of the technical scheme of the invention, the compound is prepared by grafting 5-15 parts by weight of gelatin and 0.5-1.5 parts by weight of SbQ.

As a further description of the technical scheme of the invention, the hemiacetal group in the SbQ molecule and the hydroxyl group in the gelatin molecule are subjected to condensation dehydration reaction to form a covalent bond, and then the covalent bond is connected to the gelatin molecule.

In the photo-curable compound, Gelatin molecule is used as basic skeleton, N-methyl-4- (p-formylstyryl) pyridine methyl sulfate (SbQ) molecule is grafted, hemiacetal group in SbQ molecule can generate condensation dehydration reaction with hydroxyl group in Gelatin molecule to form covalent bond, thereby connecting to Gelatin molecule to form compound photo-curable compound Gelatin- [ N-methyl-4- (p-formylstyryl) pyridine methyl sulfate ] (Gelatin-SbQ). SbQ group in the compound is photosensitive, and can generate polymerization crosslinking under the irradiation of ultraviolet light or blue light to form hydrogel.

The present invention also provides a method for preparing the above photocurable compound, which comprises the steps of:

s1.SbQ synthesis: taking 25-60 parts of terephthalaldehyde, 9-19 parts of gamma-methylpyridine, 25-30 parts of acetic anhydride and 10-15 parts of acetic acid according to parts by weight, fully mixing, and heating and refluxing for 6-8 hours at 100 ℃; adding 300 portions of 1mol/L hydrochloric acid, standing for 1-2 hours at room temperature, and filtering unreacted precipitates; heating the filtrate to 30-40 deg.C, extracting with benzene to remove terephthalaldehyde, adding 1mol/L sodium hydroxide solution to adjust to neutrality; filtering, collecting yellow precipitate, washing with pure water, air drying, heating to 70-80 deg.C with 30-40 parts of ethyl acetate for dissolving, and filtering to remove insoluble substances; adding 50 parts of dimethyl sulfate into the filtrate, standing overnight, filtering, washing and drying by using methanol and acetone, and collecting insoluble substances to obtain SbQ;

s2, synthesis of Gelatin-SbQ: taking 5-15 parts of gelatin, adding 100-300 parts of distilled water, magnetically stirring, heating and dissolving until the gelatin is clear and transparent, adding 0.5-1.5 parts of SbQ, and magnetically stirring to react at 40-80 ℃ for 12-24 hours; adding 11mol/L sodium hydroxide solution to adjust the pH value to 6-7, washing and drying by using methanol and acetone, and collecting insoluble substances to obtain Gelatin-SbQ.

Further, the reactions of S1 and S2 were both performed under a dark environment.

Further, the gelatin is type a gelatin, and its BLOOM value corresponds to 300g jelly strength.

Modifying SbQ molecules on gelatin molecules, specifically, generating N-methyl-4- (p-formylstyryl) pyridine by nucleophilic addition reaction of benzene dicarbaldehyde and gamma-methylpyridine under the action of acetic anhydride; then adding dimethyl sulfate to form SbQ molecules; finally, the SbQ molecule and hydroxyl in the Gelatin molecule are subjected to aldol condensation reaction, so that the SbQ molecule is grafted to the Gelatin molecule to form a new light-curable compound Gelatin-SbQ.

Adding purified water into the prepared Gelatin-SbQ, magnetically stirring, heating and dissolving until the mixture is clear and transparent, wherein the Gelatin-SbQ aqueous solution can be used for photocuring reaction and can trigger the photocuring reaction in the wavelength range of ultraviolet light or blue light (350-. Wherein, the higher the Gelatin-SbQ concentration is, the faster the crosslinking speed is and the higher the crosslinking degree is.

The photocurable compound and the photocurable compound prepared by the preparation method are applied to 3D printing, and gelatin is a biological macromolecule with good biocompatibility and is commonly used as a food and drug additive; the Gelatin-SbQ is safe, nontoxic and biodegradable. The photocuring can be completed without adding exogenous photoinitiators.

The biological ink containing the compound has good biocompatibility and degradability, and is good 3D printing biological ink.

Based on the technical scheme, the invention has the following technical effects:

(1) the photo-curable compound provided by the invention directly grafts a photosensitive group SbQ onto a gelatin molecule, and can be subjected to photo-curing polymerization under ultraviolet light to form gel without adding an exogenous photoinitiator; and the compound takes gelatin molecules with good biocompatibility as basic skeletons, is safe and nontoxic, and has good biocompatibility and biodegradability.

(2) The preparation method of the light-curable compound comprises the steps of firstly, generating N-methyl-4- (p-formyl styryl) pyridine by nucleophilic addition reaction of benzene dicarbaldehyde and gamma-methylpyridine under the action of acetic anhydride; then adding dimethyl sulfate to form SbQ molecules; finally, the SbQ molecule and hydroxyl in the Gelatin molecule are subjected to aldol condensation reaction, so that the SbQ molecule is grafted to the Gelatin molecule to form a new photo-curable compound Gelatin-SbQ.

Drawings

FIG. 1 is a graph showing infrared absorption spectra of Gelatin (Gelatin) and Gelatin-SbQ (Gelatin-SbQ) in example 1.

FIG. 2 is a graph showing UV-visible absorption spectra of Gelatin (Gelatin) and Gelatin-SbQ (Gelatin-SbQ) in example 1.

FIG. 3 is a schematic diagram showing the cycloaddition reaction of Gelatin-SbQ (Gelatin-SbQ) in example 1 upon photocuring.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the following specific embodiments and accompanying drawings. The invention provides a preferred embodiment. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Example 1

A photocurable compound, which is prepared by grafting N-methyl-4- (p-formylstyryl) pyridylmethylsulfate (SbQ) onto Gelatin as basic skeleton, is Gelatin- [ N-methyl-4- (p-formylstyryl) pyridylmethylsulfate ] (geltin-SbQ). The preparation method comprises the following steps:

(1) s1.SbQ synthesis: taking 26.8-53.7g of terephthalaldehyde, 9.3-18.6g of gamma-methylpyridine, 25-30ml of acetic anhydride and 10-14ml of acetic acid, fully mixing, and heating and refluxing for 6-8 hours at 100 ℃; adding 300-500ml of 1mol/L hydrochloric acid, standing at room temperature for 1-2 hours, and filtering unreacted precipitates; heating the filtrate to 30-40 deg.C, extracting with benzene to remove terephthalaldehyde, adding 1mol/L sodium hydroxide solution to adjust pH to neutral; filtering, collecting yellow precipitate, washing with pure water, air drying, dissolving with 30-40ml ethyl acetate at 70-80 deg.C, filtering to remove insoluble substances, and collecting filtrate as N-methyl-4- (p-formylstyryl) pyridine; adding 50ml dimethyl sulfate into the filtrate, standing overnight, filtering, washing with methanol and acetone, drying, and collecting insoluble substances to obtain N-methyl-4- (p-formylstyryl) pyridine methyl sulfate (SbQ); the reaction was carried out in a dark environment. The reaction formula is as follows:

(2) s2, synthesis of Gelatin-SbQ: taking 5-15g of gelatin (type A gelatin, the BLOOM value of which is equivalent to 300g of jelly strength) powder, adding 100-300g of distilled water, magnetically stirring, heating and dissolving until the mixture is clear and transparent, adding 0.5-1.5g of SbQ prepared by the method, and magnetically stirring to react at 40-80 ℃ for 12-24 hours; adding 11mol/L sodium hydroxide solution to adjust the pH value to 6-7, washing and drying by using methanol and acetone, and collecting insoluble substances to obtain Gelatin-SbQ. The reaction was carried out in a dark environment. The reaction formula is as follows:

FIG. 1 is a graph showing the infrared absorption spectra of Gelatin (Gelatin) and Gelatin-SbQ (Gelatin-SbQ), and the infrared absorption curve of Gelatin-SbQ is 1630cm in comparison with the infrared absorption curve of Gelatin, as shown in FIG. 1^-1The absorption at (characteristic absorption peak of SbQ group) is evident.

FIG. 2 is a graph showing the UV-VIS absorption spectrum of Gelatin-SbQ (Gelatin-SbQ), wherein the Gelatin-SbQ has a relatively stable characteristic absorption peak under the irradiation of light with a wavelength of 330-420nm, as shown in FIG. 2.

(3) S3, preparing a Gelatin-SbQ aqueous solution: taking Gelatin-SbQ, adding purified water, magnetically stirring, heating and dissolving until the mixture is clear and transparent.

The Gelatin-SbQ aqueous solution can be used for photocuring reaction, and can trigger the photocuring reaction in the wavelength range of ultraviolet light or blue light (350-. Wherein the higher the Gelatin-SbQ concentration is, the faster the crosslinking speed is and the higher the crosslinking degree is.

FIG. 3 shows a schematic diagram of the cycloaddition reaction of Gelatin-SbQ (Gelatin-SbQ) during photo-curing, and as shown in FIG. 3, the unsaturated double bond in the SbQ group of the Gelatin-SbQ compound provided in this example can undergo a cycloaddition reaction with the unsaturated double bond in the adjacent SbQ group under the irradiation of ultraviolet light or blue-violet light (350-410nm), so as to undergo a photo-curing crosslinking reaction and form a hydrogel.

The compound directly grafts a photosensitive group SbQ on gelatin molecules, and can carry out photocuring polymerization under ultraviolet light to form gel without adding an exogenous photoinitiator; and the compound takes gelatin molecules with good biocompatibility as basic skeletons, is safe and nontoxic, and has good biocompatibility and biodegradability.

Example 2

A photocurable compound, which is prepared by grafting N-methyl-4- (p-formylstyryl) pyridylmethylsulfate (SbQ) onto Gelatin as basic skeleton, is Gelatin- [ N-methyl-4- (p-formylstyryl) pyridylmethylsulfate ] (geltin-SbQ). The preparation method comprises the following steps:

(1) s1.SbQ synthesis: taking 28-52g of terephthalaldehyde, 10-15g of gamma-methylpyridine, 28-30ml of acetic anhydride and 12-14ml of acetic acid, fully mixing, and heating and refluxing for 6-8 hours at 100 ℃; adding 350-500ml of 1mol/L hydrochloric acid, standing at room temperature for 1-2 hours, and filtering unreacted precipitates; heating the filtrate to 30-40 deg.C, extracting with benzene to remove terephthalaldehyde, adding 1mol/L sodium hydroxide solution to adjust pH to neutral; filtering, collecting yellow precipitate, washing with pure water, air drying, dissolving with 35-40ml ethyl acetate at 70-80 deg.C, filtering to remove insoluble substances, and collecting filtrate as N-methyl-4- (p-formylstyryl) pyridine; adding 50ml dimethyl sulfate into the filtrate, standing overnight, filtering, washing with methanol and acetone, drying, and collecting insoluble substances to obtain N-methyl-4- (p-formylstyryl) pyridine methyl sulfate (SbQ); the reaction was carried out in a dark environment. The reaction scheme is the same as in example 1.

(2) S2, synthesis of Gelatin-SbQ: taking 10-15g of gelatin (type A gelatin, the BLOOM value of which is equivalent to 300g of jelly strength) powder, adding 200-300g of distilled water, magnetically stirring, heating and dissolving until the mixture is clear and transparent, adding 1.0-1.5g of SbQ prepared by the method, and magnetically stirring to react at 40-80 ℃ for 12-24 hours; adding 11mol/L sodium hydroxide solution to adjust the pH value to 6-7, washing and drying by using methanol and acetone, and collecting insoluble substances to obtain Gelatin-SbQ. The reaction was carried out in a dark environment. The reaction scheme is the same as in example 1.

(3) S3, preparing a Gelatin-SbQ aqueous solution: taking Gelatin-SbQ, adding purified water, magnetically stirring, heating and dissolving until the mixture is clear and transparent. The Gelatin-SbQ aqueous solution is applied to 3D printing biological ink, unsaturated double bonds in SbQ groups can perform cycloaddition reaction with unsaturated double bonds in adjacent SbQ groups under the irradiation of ultraviolet light or blue-violet light (350-410nm), so that photocuring crosslinking reaction is performed, and hydrogel is formed. In addition, the compound takes gelatin molecules with good biocompatibility as basic skeletons, is safe and nontoxic, and has good biocompatibility and biodegradability.

Example 3

A photocurable compound, which is prepared by grafting N-methyl-4- (p-formylstyryl) pyridylmethylsulfate (SbQ) onto Gelatin as basic skeleton, is Gelatin- [ N-methyl-4- (p-formylstyryl) pyridylmethylsulfate ] (geltin-SbQ). The preparation method comprises the following steps:

(1) s1.SbQ synthesis: taking 45g of terephthalaldehyde, 12g of gamma-methylpyridine, 30ml of acetic anhydride and 13ml of acetic acid, fully mixing, and heating and refluxing for 6-8 hours at 100 ℃; adding 400ml of 1mol/L hydrochloric acid, standing at room temperature for 1-2 hours, and filtering out unreacted precipitate; heating the filtrate to 30-40 deg.C, extracting with benzene to remove terephthalaldehyde, adding 1mol/L sodium hydroxide solution to adjust pH to neutral; filtering, collecting yellow precipitate, washing with pure water, air drying, dissolving with 40ml ethyl acetate at 70-80 deg.C, filtering to remove insoluble substances, and collecting filtrate as N-methyl-4- (p-formylstyryl) pyridine; adding 50ml dimethyl sulfate into the filtrate, standing overnight, filtering, washing with methanol and acetone, drying, and collecting insoluble substances to obtain N-methyl-4- (p-formylstyryl) pyridine methyl sulfate (SbQ); the reaction was carried out in a dark environment. The reaction scheme is the same as in example 1.

(2) S2, synthesis of Gelatin-SbQ: taking 12g gelatin (type A gelatin, whose BLOOM value is equal to 300g jelly strength) powder, adding 250g distilled water, magnetically stirring, heating to dissolve until clear and transparent, adding 1.3g SbQ prepared above, and magnetically stirring to react at 40-80 deg.C for 12-24 hr; adding 11mol/L sodium hydroxide solution to adjust the pH value to 6-7, washing and drying by using methanol and acetone, and collecting insoluble substances to obtain Gelatin-SbQ. The reaction was carried out in a dark environment. The reaction scheme is the same as in example 1.

(3) S3, preparing a Gelatin-SbQ aqueous solution: taking Gelatin-SbQ, adding purified water, magnetically stirring, heating and dissolving until the mixture is clear and transparent. The Gelatin-SbQ aqueous solution is applied to 3D printing biological ink, unsaturated double bonds in SbQ groups can perform cycloaddition reaction with unsaturated double bonds in adjacent SbQ groups under the irradiation of ultraviolet light or blue-violet light (350-410nm), so that photocuring crosslinking reaction is performed, and hydrogel is formed. In addition, the compound takes gelatin molecules with good biocompatibility as basic skeletons, is safe and nontoxic, and has good biocompatibility and biodegradability.

Example 4

A photocurable compound, which is prepared by grafting N-methyl-4- (p-formylstyryl) pyridylmethylsulfate (SbQ) onto Gelatin as basic skeleton, is Gelatin- [ N-methyl-4- (p-formylstyryl) pyridylmethylsulfate ] (geltin-SbQ). The preparation method comprises the following steps:

(1) s1.SbQ synthesis: taking 28g of terephthalaldehyde, 10g of gamma-methylpyridine, 28-ml of acetic anhydride and 12ml of acetic acid, fully mixing, and heating and refluxing for 6-8 hours at 100 ℃; adding 350ml of 1mol/L hydrochloric acid, standing for 1-2 hours at room temperature, and filtering out unreacted precipitate; heating the filtrate to 30-40 deg.C, extracting with benzene to remove terephthalaldehyde, adding 1mol/L sodium hydroxide solution to adjust pH to neutral; filtering, collecting yellow precipitate, washing with pure water, air drying, dissolving with 38ml ethyl acetate at 70-80 deg.C, filtering to remove insoluble substances, and collecting filtrate as N-methyl-4- (p-formylstyryl) pyridine; adding 50ml dimethyl sulfate into the filtrate, standing overnight, filtering, washing with methanol and acetone, drying, and collecting insoluble substances to obtain N-methyl-4- (p-formylstyryl) pyridine methyl sulfate (SbQ); the reaction was carried out in a dark environment. The reaction scheme is the same as in example 1.

(2) S2, synthesis of Gelatin-SbQ: taking 12g gelatin (type A gelatin, whose BLOOM value is equal to 300g jelly strength) powder, adding 300g distilled water, magnetically stirring, heating to dissolve until clear and transparent, adding 1.5g SbQ prepared above, and magnetically stirring to react at 40-80 deg.C for 12-24 hr; adding 12mol/L sodium hydroxide solution to adjust the pH value to 6-7, washing and drying by using methanol and acetone, and collecting insoluble substances to obtain Gelatin-SbQ. The reaction was carried out in a dark environment. The reaction scheme is the same as in example 1.

(3) S3, preparing a Gelatin-SbQ aqueous solution: taking Gelatin-SbQ, adding purified water, magnetically stirring, heating and dissolving until the mixture is clear and transparent. The Gelatin-SbQ aqueous solution is applied to 3D printing biological ink, unsaturated double bonds in SbQ groups can perform cycloaddition reaction with unsaturated double bonds in adjacent SbQ groups under the irradiation of ultraviolet light or blue-violet light (350-410nm), so that photocuring crosslinking reaction is performed, and hydrogel is formed. In addition, the compound takes gelatin molecules with good biocompatibility as basic skeletons, is safe and nontoxic, and has good biocompatibility and biodegradability.

Example 5

A photocurable compound, which is prepared by grafting N-methyl-4- (p-formylstyryl) pyridylmethylsulfate (SbQ) onto Gelatin as basic skeleton, is Gelatin- [ N-methyl-4- (p-formylstyryl) pyridylmethylsulfate ] (geltin-SbQ). The preparation method comprises the following steps:

(1) s1.SbQ synthesis: taking 50g of terephthalaldehyde, 15g of gamma-methylpyridine, 30ml of acetic anhydride and 14ml of acetic acid, fully mixing, and heating and refluxing for 6-8 hours at 100 ℃; adding 500ml of 1mol/L hydrochloric acid, standing for 1-2 hours at room temperature, and filtering out unreacted precipitate; heating the filtrate to 30-40 deg.C, extracting with benzene to remove terephthalaldehyde, adding 1mol/L sodium hydroxide solution to adjust pH to neutral; filtering, collecting yellow precipitate, washing with pure water, air drying, dissolving with 40ml ethyl acetate at 70-80 deg.C, filtering to remove insoluble substances, and collecting filtrate as N-methyl-4- (p-formylstyryl) pyridine; adding 50ml dimethyl sulfate into the filtrate, standing overnight, filtering, washing with methanol and acetone, drying, and collecting insoluble substances to obtain N-methyl-4- (p-formylstyryl) pyridine methyl sulfate (SbQ); the reaction was carried out in a dark environment. The reaction scheme is the same as in example 1.

(2) S2, synthesis of Gelatin-SbQ: taking 15g of gelatin (type A gelatin, the BLOOM value of which is equivalent to 300g of jelly strength) powder, adding 300g of distilled water, magnetically stirring, heating to dissolve until the mixture is clear and transparent, adding 1.5g of SbQ prepared above, and magnetically stirring to react at 40-80 ℃ for 12-24 hours; adding 11mol/L sodium hydroxide solution to adjust the pH value to 6-7, washing and drying by using methanol and acetone, and collecting insoluble substances to obtain Gelatin-SbQ. The reaction was carried out in a dark environment. The reaction scheme is the same as in example 1.

(3) S3, preparing a Gelatin-SbQ aqueous solution: taking Gelatin-SbQ, adding purified water, magnetically stirring, heating and dissolving until the mixture is clear and transparent. The Gelatin-SbQ aqueous solution is applied to 3D printing biological ink, unsaturated double bonds in SbQ groups can perform cycloaddition reaction with unsaturated double bonds in adjacent SbQ groups under the irradiation of ultraviolet light or blue-violet light (350-410nm), so that photocuring crosslinking reaction is performed, and hydrogel is formed. In addition, the compound takes gelatin molecules with good biocompatibility as basic skeletons, is safe and nontoxic, and has good biocompatibility and biodegradability.

The foregoing is illustrative and explanatory only, and is described in greater detail and detail, but is not to be construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications are possible without departing from the inventive concept, and such obvious alternatives fall within the scope of the invention.