阅读说明：本技术 一种高机械强度的蛛丝蛋白-胶原蛋白复合水凝胶的制备方法 (Preparation method of high-mechanical-strength spidroin-collagen composite hydrogel ) 是由 包子娴 年锐 咸漠 孙粤 陈泉 刘文帅 彭馨莹 于 2018-07-05 设计创作，主要内容包括：本发明公开了一种高机械强度的蛛丝蛋白-胶原蛋白复合水凝胶的制备方法,属于水凝胶技术领域。该方法是将蛛丝蛋白溶解于甲酸,胶原蛋白溶解于酸溶液,得到蛛丝蛋白甲酸溶液和胶原蛋白酸溶液,将蛛丝蛋白甲酸溶液逐滴加入到胶原蛋白酸溶液中,经由碱性溶液中和至pH呈中性,室温静置,形成蛛丝蛋白-胶原蛋白复合水凝胶。本发明制得的复合水凝胶具有生物可降解性、生物相容性、细胞粘附性,蛛丝蛋白的加入显著提高了复合水凝胶的机械性能,制备工艺简单、易操作,制备过程不涉及毒副作用试剂,绿色环保,成本低廉,在组织工程、医学等领域具有广阔的应用前景。(The invention discloses a preparation method of high-mechanical-strength spidroin-collagen composite hydrogel, belonging to the technical field of hydrogel. Dissolving spidroin in formic acid, dissolving collagen in acid solution to obtain spidroin formic acid solution and collagen acid solution, dropwise adding the spidroin formic acid solution into the collagen acid solution, neutralizing with alkaline solution until pH is neutral, and standing at room temperature to obtain the spidroin-collagen composite hydrogel. The composite hydrogel prepared by the invention has biodegradability, biocompatibility and cell adhesion, the mechanical property of the composite hydrogel is obviously improved by adding the spidroin, the preparation process is simple and easy to operate, no toxic or side effect reagent is involved in the preparation process, the preparation method is green and environment-friendly, the cost is low, and the preparation method has wide application prospects in the fields of tissue engineering, medicine and the like.)

1. A preparation method of high-mechanical-strength spidroin-collagen composite hydrogel is characterized by comprising the following steps:

1) dissolving spidroin in formic acid to obtain spidroin formic acid solution;

2) dissolving collagen in an acid solution to obtain a collagen acid solution;

3) dropwise adding the spidroin formic acid solution into the collagen acid solution, and stirring at 4 ℃ to obtain a spidroin-collagen mixed solution;

4) adjusting the pH value of the spider silk protein-collagen mixed solution to be neutral, and standing at room temperature to form the spider silk protein-collagen composite hydrogel.

2. The method according to claim 1, wherein the concentration of the spidroin formic acid solution of step 1) is from 0.01g/mL to 1 g/mL; the concentration of the collagen acid solution in the step 2) is 5mg/mL-20 mg/mL.

3. The method according to claim 1, wherein the acid solution in step 2) is a hydrochloric acid solution or an acetic acid solution.

4. The method according to claim 1, wherein step 3) controls the spider silk protein to collagen protein mass ratio to be (0.01-5) during dropwise addition of the spider silk protein formic acid solution to the collagen acid solution: 1.

5. the method according to claim 1, wherein step 3) controls the spider silk protein to collagen protein mass ratio to be (0.1-0.5) during the dropwise addition of the spider silk protein formic acid solution to the collagen acid solution: 1.

6. the method according to claim 1, wherein the collagen of step 2) is selected from any one of fish skin collagen, mammalian collagen and human-like collagen.

7. The method according to claim 1, wherein the spidroin protein of step 1) is a natural spidroin protein or an artificially synthesized spidroin protein obtained by fermentation of genetically engineered bacteria.

8. The method according to claim 1, wherein the amino acid sequence of the spidroin protein of step 1) is derived from any one or more of Lorachnoid spider (Nephila Clavipes), Lorachnoid spider (Nephila antipodiana), Acanthopanax papillaris (Gastheracantha cancriformis), Lorachnoid biostrata (Parawixia bistriata), Lorachnoid spider (Argiopedientaria), and Lorachnoid spider (Araneus diadematus).

9. The method according to claim 1, wherein the spidroin protein of step 1) has a molecular weight of 3kD to 300 kDa; the amino acid sequence of the spider silk protein comprises a plurality of alanine repeating sequences and a plurality of glycine repeating sequences, wherein the glycine content is 20% -60%, and the alanine content is 10-60%.

10. The method according to claim 1, wherein the spidroin protein of step 1) has an amino acid sequence selected from any one of MaSp1, MaSp2 and eADF 4; wherein: the amino acid sequence of MaSp1 is composed of n amino acid repeating units shown as SEQ ID NO.1, the amino acid sequence of MaSp2 is composed of n amino acid repeating units shown as SEQ ID NO.2, the amino acid sequence of eADF4 is composed of n amino acid repeating units shown as SEQ ID NO.3, and n is an integer greater than or equal to 1.

Technical Field

The invention relates to a preparation method of high-mechanical-strength spidroin-collagen composite hydrogel, belonging to the technical field of hydrogel.

Background

Spider silk is a natural protein fiber, has excellent mechanical properties such as high strength, high elasticity and high breaking energy, biological properties such as biocompatibility and biodegradability, and comprehensive properties far exceeding those of silk and artificial fibers, so that the spider silk protein has potential application value in the fields of materials, textiles, military equipment, biomedicine and the like. Spiders are not easy to raise on a large scale, so the natural spider silks mainly come from nettings and the yield is very low. In order to improve the yield of the spidroin protein, the stable expression of the spidroin protein in engineering bacteria is realized by means of genetic engineering modification. The current application forms of spidroin protein comprise microspheres and spinning fiber membranes, and are used in the fields of drug delivery systems, wound dressings and the like. Due to the influence of the water solubility of the spidroin, the simple spidroin is difficult to form gel materials, and the application of the gel materials is limited to a certain extent.

The collagen is the main component in the extracellular matrix, has the characteristics of biocompatibility, biodegradability, cell adhesion, low immunogenicity and the like, and has wide application in the aspects of drug delivery, skin substitutes, tissue engineering and the like. The current commercialized collagen is mainly derived from pig skin, bovine achilles tendon, etc., but the high extraction cost and the possibility of virus transmission limit the application of mammalian collagen. The fish skin and other aquatic product processing wastes are one of the sources for obtaining the collagen, the price is low, the safety is high, and therefore, the fish collagen gradually occupies a place in market application. However, the collagen from either mammalian or marine sources forms hydrogels with poor mechanical properties, which limits their applications to some extent.

The literature reports that the mechanical property of the collagen hydrogel can be improved by adding the cross-linking agent, but the biological safety of the cross-linking agent has certain hidden trouble. Therefore, the development of the collagen composite hydrogel of biological sources can not only ensure the biological safety of the material, but also improve the mechanical property of the material. At present, there is no report on spider silk protein and collagen composite materials.

Disclosure of Invention

In order to make up the defects and shortcomings of collagen hydrogel and spidroin materials in the application aspect, the invention provides a preparation method of high-mechanical-property spidroin-collagen composite hydrogel, the prepared composite hydrogel combines the advantages of spidroin and collagen, has good mechanical property and biological safety, can be applied to the fields of tissue engineering and the like, and adopts the following technical scheme:

the invention aims to provide a preparation method of high-mechanical-property spidroin-collagen composite hydrogel, which comprises the following steps:

1) dissolving spidroin in formic acid to obtain spidroin formic acid solution;

2) dissolving collagen in an acid solution to obtain a collagen acid solution;

3) dropwise adding the spidroin formic acid solution into the collagen acid solution, and stirring at 4 ℃ to obtain a spidroin-collagen mixed solution;

4) adjusting the pH value of the spider silk protein-collagen mixed solution to be neutral, and standing at room temperature to form the spider silk protein-collagen composite hydrogel.

Preferably, the acid solution in step 2) is a hydrochloric acid solution or an acetic acid solution.

Preferably, the concentration of the spidroin formic acid solution in the step 1) is 0.01g/mL-1 g/mL.

Preferably, the concentration of the collagen acid solution of step 2) is 5mg/mL-20 mg/mL.

Preferably, step 3) controls the mass ratio of the spidroin to the collagen to be (0.01-5): 1.

more preferably, step 3) controls the mass ratio of spidroin to collagen to be (0.1-0.5) during the dropwise addition of the spidroin formic acid solution to the collagen acid solution: 1.

optimally, step 3) controls the mass ratio of the spider silk protein to the collagen protein to be 0.5: 1.

preferably, the collagen of step 2) is fish skin collagen, mammalian collagen (e.g. porcine, bovine) or human-like collagen. Most preferably, the collagen of step 2) is fish skin collagen. Experiments show that the collagen in the invention can be selected from fish skin collagen, human-like collagen and mammalian collagen (such as pig and cow), the collagen is suitable for the method of the invention, and the mechanical properties of the composite hydrogel prepared by using the collagen are obviously improved compared with the simple collagen hydrogel, wherein the mechanical strength of the spidroin-collagen composite hydrogel obtained by using the fish skin collagen is the best.

Preferably, the spidroin protein in the step 1) is natural spidroin protein or artificially synthesized spidroin protein obtained by fermentation of genetically engineered bacteria.

Preferably, the amino acid sequence of the spidroin protein of step 1) is derived from any one or more of golden cobweb (Nephila clavipes), Nephila argentea (Nephila antipodaiana), Cratoxylum nipple (Gastheracanthacriformis), Parawiia bistriata (Parawiia bistriata), Arachis (Argiope aurantia), and Araneus diadematus (Araneus diadematus).

Preferably, the spidroin protein of step 1) has a molecular weight of 3kDa to 300 kDa; the amino acid sequence of the spider silk protein comprises a plurality of alanine repeating sequences and a plurality of glycine repeating sequences, wherein the glycine content is 20% -60%, and the alanine content is 10-60%.

Preferably, the amino acid sequence of the spidroin protein is selected from any one of MaSp1, MaSp2 and eADF 4; wherein:

the amino acid sequence of MaSp1 (major ampullate spidroin 1) is composed of n amino acid repeating units shown as SEQ ID NO.1, and the specific amino acid sequence is as follows: [ SGRGGLGGQGAGAAAAAGGAGQGGYGGLGSQGT ] n; wherein n is an integer greater than or equal to 1;

the amino acid sequence of MaSp2 (major ampullate spidroin 2) is composed of n amino acid repeating units shown as SEQ ID NO.2, and the specific amino acid sequence is as follows: [ GPGGYGPGQQGPSGPGSAAAAAAAAGPGGYGPGQQTS ] n; wherein n is an integer greater than or equal to 1.

The amino acid sequence of the eADF4 (spider silk protein 4 of Araneus diadematus) is composed of n amino acid repeating units shown as SEQ ID NO.3, and the specific amino acid sequence is as follows: [ GSSAAAAAAAASGPGGYGPENQGPSGPGGYGPGGP ] n; wherein n is an integer greater than or equal to 1.

The amino acid sequence of the spidroin protein of the present invention is not limited to the above three, and any spidroin protein obtained by fermentation of the amino acid sequence of the spidroin protein satisfying the above requirements at the same time is suitable for the present invention.

The invention relates to a preparation method of high-mechanical-strength spidroin-collagen composite hydrogel, which comprises the following specific operation steps:

(1) dissolving spidroin in formic acid, dissolving collagen in acidic solution (hydrochloric acid or acetic acid), and stirring at 4 deg.C overnight to obtain spidroin formic acid solution and collagen acid solution.

(2) Adding the spidroin formic acid solution into the collagen acid solution drop by drop, and stirring for 4 hours at 4 ℃ to obtain the spidroin-collagen mixed solution.

(3) Adding alkaline solution (potassium hydroxide, sodium hydroxide) dropwise at 0-5 deg.C until the pH value of the solution is 7. Standing at room temperature for 4-6 hr, and rinsing with deionized water for 2-3 times to obtain the final product.

The fish skin collagen of the invention can be directly purchased, and can also be extracted and purified from fish skins, such as weever and tilapia, but not limited to the two fishes, common economic fishes in China are all included, and the collagen extracted from the fish skins of other fishes is all suitable for the invention.

According to the composite hydrogel of the spider silk protein and the collagen, the spider silk protein and the collagen are compounded together in a physical mixing mode, the spider silk protein and the collagen are mainly connected through hydrogen bonds, the formation of amide bonds between molecules of the spider silk protein and the collagen is accompanied with a certain probability, a beta-folding structure formed by the spider silk protein is inserted in a net structure formed by the collagen, and the tensile resistance and the compression resistance of the beta-folding structure improve the mechanical strength of the composite hydrogel to a certain extent.

The concentration of the collagen acid solution in the invention can be 5mg/mL-20mg/mL, and because the concentration of the collagen has a great influence on the mechanical properties of the collagen hydrogel in the process of preparing the collagen hydrogel, the higher the concentration of the collagen is, the higher the mechanical strength of the prepared collagen hydrogel is correspondingly, when the mechanical strength is compared, the collagen hydrogel and the composite gel of the invention are prepared by using the collagen acid solution with the same concentration, and the comparison result can be comparable. Compared with the hydrogel prepared from the collagen acid solution with the same concentration, the mechanical strength of the composite hydrogel prepared by the invention is obviously improved, the mechanical strength effect can be better achieved by adopting 10mg/mL-20mg/mL in the experimental process, the mechanical strength of the composite hydrogel prepared from the collagen acid solution with the concentration of 20mg/mL can be obviously improved compared with the mechanical strength of the composite hydrogel prepared from the collagen acid solution with the concentration of 10mg/mL, and the composite hydrogel prepared from the collagen acid solution with the concentration of 10mg/mL is optimal in the aspects of economic cost, easy operability in the preparation process, actually required mechanical strength and the like.

The invention has the beneficial effects that:

according to the invention, the cobweb protein and the collagen are compounded to prepare the hydrogel for the first time, so that the problem that the cobweb protein is difficult to form gel materials is solved, the problem of improving the mechanical property of the collagen hydrogel is solved, the prepared composite hydrogel can ensure the biological safety of the materials and can obtain good mechanical property, the mechanical property of the cobweb protein added is obviously improved compared with that of the pure collagen hydrogel, and the composite hydrogel disclosed by the invention combines the advantages of the cobweb protein and the collagen, such as the characteristics of biodegradability, biocompatibility, cell adhesion and the like.

The spider silk protein-collagen composite hydrogel prepared by the invention is safe, has no toxic or side effect, has good biological safety, cell adhesion and mechanical property, has compression strength obviously higher than that of collagen hydrogel, can reach 0.56MPa at most, and has wide application prospect.

According to the invention, the spider silk protein and the collagen are used as raw materials, and are mixed in different proportions to prepare the composite hydrogel through an acid dissolution and alkali neutralization method.

Drawings

FIG. 1 is a stress-strain curve of a spidroin-collagen (SF/Col) composite hydrogel.

Detailed Description

The present invention will be further described with reference to the following specific examples, but the present invention is not limited to these examples.

The collagen adopted by the method can be purchased through commercial approaches and can also be obtained by self-extraction and purification, the following embodiment takes the fish skin collagen as an example for illustration, the self-extracted and purified fish skin collagen can be obtained by extraction and purification through a pepsin digestion method, and the specific extraction method is as follows: cutting 5g of dried fish skin, adding 0.1M sodium hydroxide solution, washing for 36 hours, changing the solution every 12 hours, and centrifuging to remove supernatant; adding 10% isopropanol solution into the precipitate, stirring for 36 hr, changing solution every 12 hr, centrifuging to remove supernatant; adding 0.5M glacial acetic acid solution containing pepsin (1.25g) into the precipitate, digesting for 48 hr, and centrifuging to remove precipitate; slowly adding 4.45M sodium chloride solution into the supernatant until the final concentration of sodium chloride is 0.84-0.89M, and centrifuging to remove the supernatant; dissolving the precipitate in 0.1M glacial acetic acid solution, dialyzing with 0.02M disodium hydrogen phosphate solution for 36 hours, and centrifuging to remove supernatant; dissolving the precipitate in 0.5M glacial acetic acid solution, filtering, dialyzing with distilled water for 48 hours, and freeze-drying to obtain fish skin collagen sample with purity higher than 99%.

The spidroin proteins used in the following examples were obtained commercially. The spider silk protein adopted by the method can be natural spider silk protein or artificially synthesized spider silk protein obtained by fermentation of genetically engineered bacteria. The amino acid sequence of the spider silk protein may be derived from any one or more of Nephila Clavipes, Nephila cerifera, Acanthopanax papillaris, Arabian nephridatista, Arabian Aurantia, and Araneus diadematus. The spider silk protein has a molecular weight of 3kDa-300 kDa; the amino acid sequence of the spider silk protein comprises a plurality of alanine repeating sequences and a plurality of glycine repeating sequences, wherein the glycine content is 20-60%, and the alanine content is 10-60%. The following examples illustrate the following spidroin proteins which meet the above requirements: MaSp1 (major ampullate spidroin 1): [ SGRGGLGGQGAGAAAAAGGAGQGGYGGLGSQGT ] n, MaSp2 (major ampullate spidroin 2): [ GPGGYGPGQQGPSGPGSAAAAAAAAGPGGYGPGQQTS ] n, eADF4 (Araneus diadematus spider silk protein 4): [ GSSAAAAAAAASGPGGYGPENQGPSGPGGYGPGGP ] n, wherein n is an integer greater than or equal to 1.

The preparation method of the spider silk protein-collagen composite hydrogel comprises the following steps: the spidroin protein is dissolved in formic acid, and the collagen protein is dissolved in acidic solution (hydrochloric acid or acetic acid), and stirred overnight at 4 deg.C. Dropwise adding the obtained spidroin formic acid solution into the collagen acid solution, and stirring at 4 ℃ for 4 hours to obtain the spidroin-collagen mixed solution. Dropwise adding alkaline solution (potassium hydroxide and sodium hydroxide) into the spider silk protein-collagen mixed solution at 0-5 ℃ until the pH value is 7, pouring the neutralized mixed solution into a mold, standing at room temperature for 4-6 hours, and after gelation is finished, rinsing the gel with deionized water for 2-3 times to obtain the spider silk protein-collagen composite hydrogel.