阅读说明：本技术 一种酶法制备柔性导电丝素蛋白膜的方法 (Method for preparing flexible conductive silk fibroin membrane by enzyme method ) 是由 王平 袁晶晶 农叶琳 余圆圆 王强 于 2019-09-17 设计创作，主要内容包括：本发明公开了一种酶法制备柔性导电丝素蛋白膜的方法,通过丝素与含氨基的聚乙二醇反应,改善丝素膜的柔顺性；再以漆酶催化氧化吡咯自聚和与丝素蛋白中酪氨酸接枝聚合,赋予丝素膜导电性,制备柔性导电丝素蛋白膜材料。具体包括以下步骤：(1)丝素蛋白接枝端基含氨基的聚乙二醇；(2)漆酶催化吡咯自聚和与丝素蛋白接枝聚合；(3)柔性导电膜丝素蛋白膜成型。与通过共混法或化学引发法制备丝素导电膜材料相比,本发明具有酶催化效率高、反应条件缓和、丝素膜柔性和导电性能改善明显的优点。(the invention discloses a method for preparing a flexible conductive silk fibroin membrane by an enzyme method, wherein the flexibility of the silk fibroin membrane is improved by the reaction of silk fibroin and amino-containing polyethylene glycol; then, laccase is used for catalyzing the oxidation pyrrole to be self-polymerized and grafted and polymerized with tyrosine in the silk fibroin, so that the silk fibroin film is endowed with conductivity, and the flexible conductive silk fibroin film material is prepared. The method specifically comprises the following steps: (1) polyethylene glycol with amino-containing silk fibroin grafting end group; (2) the laccase catalyzes pyrrole self-polymerization and silk fibroin graft polymerization; (3) and forming the silk fibroin film by using the flexible conductive film. Compared with the fibroin conductive film material prepared by a blending method or a chemical initiation method, the method has the advantages of high enzyme catalysis efficiency, mild reaction conditions and obviously improved flexibility and conductivity of the fibroin film.)

1. A method for preparing flexible conductive silk fibroin membrane material by enzyme method comprises grafting polyethylene glycol with amino group at terminal group onto silk fibroin molecule by using 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide; then, pyrrole is oxidized by laccase catalysis, self polymerization is carried out, and pyrrole and silk fibroin molecule graft polymerization are carried out, so that the conductive silk fibroin membrane material is prepared.

2. the method for preparing the flexible conductive silk fibroin membrane material by the enzyme method according to claim 1, which is characterized by comprising the following steps:

(1) Polyethylene glycol with amino-containing silk fibroin grafting end group: carrying out one-bath reaction on silk fibroin, polyethylene glycol with an amino group at the end group, 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide, dialyzing the mixed solution with deionized water for 24 hours after the reaction, removing the 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride, the N-hydroxysuccinimide and unreacted polyethylene glycol with the amino group at the end group, and then carrying out freeze drying at-50 ℃ to obtain modified silk fibroin;

(2) the laccase catalyzes pyrrole self-polymerization and silk fibroin graft polymerization: adding the silk fibroin modified in the step (1) into a pyrrole solution, adding laccase, and catalyzing self-polymerization of pyrrole and graft polymerization of pyrrole and silk fibroin molecules;

(3) Forming a flexible conductive film silk fibroin film: pouring the mixed solution treated in the step (2) into a polytetrafluoroethylene mold, and drying and molding at 25 ℃.

3. The method for preparing the hyaluronic acid-based conductive membrane material by the enzymatic method according to claim 2, wherein in the step (1), the content of silk fibroin is 20-40 g/L, and the molecular weight of the silk fibroin is 400-600; the concentration of the polyethylene glycol with the amino group at the end group is 5-10 g/L; the concentration of the 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride is 2.5-5 g/L; the concentration of the N-hydroxysuccinimide is 2.5-5 g/L.

4. The method for preparing the hyaluronic acid-based conductive membrane material by the enzymatic method according to claim 2, wherein in the step (1), the reaction conditions are as follows: the pH value is 5-7, the temperature is 25-40 ℃, and the time is 4-24 hours.

5. The method for preparing the hyaluronic acid-based conductive membrane material by the enzymatic method according to claim 2, wherein in the step (2), the addition amount of the modified silk fibroin is 20-40 g/L, the concentration of pyrrole is 20-40 g/L, and the concentration of laccase is 0.2-1U/mL.

6. The method for preparing the hyaluronic acid-based conductive membrane material by the enzymatic method according to claim 2, wherein in the step (2), the catalytic reaction conditions are as follows: the pH value is 4.5-6, the temperature is 25-50 ℃, and the time is 8-12 hours.

7. The hyaluronic acid-based conductive film material prepared by the method for preparing the hyaluronic acid-based conductive film material by the enzymatic method according to any one of claims 1 to 6.

Technical Field

The invention relates to a method for preparing a flexible conductive silk fibroin membrane by an enzyme method, belonging to the technical field of textile biology.

background

The silk fibroin is the main component of silk and is composed of 18 amino acids, wherein most of the amino acids are low-polarity ethyl amino acid and alanine chain segments, and the rest of the amino acids are mainly composed of polar amino acids, such as glutamic acid and aspartic acid containing carboxyl, tyrosine containing phenolic hydroxyl and the like. The silk fibroin has good biocompatibility, and the membrane material processed by taking the silk fibroin as a raw material has the characteristics of no toxicity, no irritation, excellent hygroscopicity and the like. In the preparation of the silk fibroin film, the forming effect and the structural stability of the material depend on silk fibroin macromolecules, and the pure silk fibroin film material prepared by air drying at room temperature is hard and brittle, has poor elasticity and high resistance. In order to improve the performance (such as flexibility and conductivity) of the silk fibroin film and expand the application of the silk fibroin film in the field of flexible conductive materials including wearable electronic devices, modification processing needs to be carried out on silk fibroin.

The low molecular weight polyethylene glycol (PEG for short) has better plasticizing effect, and can improve the flexibility of the molding membrane material by blending with the silk fibroin, so that the breaking elongation of the silk fibroin membrane is increased, the rigidity is reduced, and the flexibility is improved. The flexibility of the silk fibroin membrane can be improved by doping PEG in the blending method, and the defects are that the PEG of the membrane material is easy to dissolve in water, so that the flexibility of the silk fibroin membrane after water immersion is reduced, and the breaking elongation of the membrane material is reduced. If the amino-containing PEG is used for silk fibroin modification and is grafted on silk fibroin macromolecules, the prepared silk fibroin membrane can obtain more lasting flexibility.

in the preparation of the conductive silk fibroin film, methods which can be adopted comprise a blending method, a chemical initiation method and an enzyme catalysis modification method. The blending method is simple and convenient to apply, the goal of preparing the conductive silk fibroin film is achieved by blending silk fibroin and conductive polymers and then paving the film, and the defects are that the effect of homogenizing and distributing the conductive polymers in the finished product in the material is not ideal, and the material resistance is large. The chemical initiation method is widely applied and has the principle that pyrrole or aniline and other monomers dissolved in a fibroin solution are initiated to polymerize by means of persulfate to form a fibroin/polypyrrole or fibroin/polyaniline composite membrane material. Such methods also have certain disadvantages, including chemical initiators remaining in the membrane material, reducing the biological safety of the material, etc. In recent years, the research on the preparation of a silk fibroin conductive film by an enzymatic method has been emphasized. Compared with a chemical initiator, the method has mild treatment conditions, and the enzyme belongs to protein molecules, so that the biological safety of the silk fibroin material is slightly influenced.

In order to solve the problems, according to the characteristic that the silk fibroin contains more carboxyl groups, the polyethylene glycol with low molecular weight end group containing amino can be grafted to the silk fibroin molecules by means of 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide (EDC/NHS), so that the flexibility of the silk fibroin film is improved. When the laccase is used for catalyzing the silk fibroin and pyrrole mixed solution, the laccase has three functions: (1) catalyzing and oxidizing pyrrole to polymerize to form polypyrrole macromolecules with a conductive effect; (2) cross-linking occurs between the catalytic oxidation silk fibroin macromolecules; (3) tyrosine in the silk fibroin is catalyzed and oxidized to generate quinone active groups, the silk fibroin and pyrrole molecules are initiated to carry out graft polymerization, polypyrrole macromolecules connected with the silk fibroin are formed, and the durability of the conductive effect of the silk fibroin film material is improved. The idea provides a new method for preparing the flexible conductive silk fibroin film with excellent mechanical property and conductivity.

disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a method for preparing a flexible conductive silk fibroin membrane material by an enzyme method, and the silk fibroin membrane material with good flexible mechanical property, excellent conductive performance and lasting conductive effect can be prepared by using the method.

The technical scheme is as follows: in order to solve the technical problems, the invention provides the following technical scheme:

a method for preparing flexible conductive silk fibroin membrane material by enzyme method comprises grafting polyethylene glycol with amino group at terminal group onto silk fibroin molecule by 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide; then, the conductive silk fibroin membrane material is prepared by catalyzing and oxidizing pyrrole self-polymerization and pyrrole and silk fibroin molecule graft polymerization by virtue of laccase.

a method for preparing a flexible conductive silk fibroin membrane material by an enzyme method comprises the following steps:

(1) Polyethylene glycol with amino-containing silk fibroin grafting end group: performing one-bath reaction on silk fibroin, polyethylene glycol with amino at the end group, 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide, dialyzing the mixed solution with deionized water for 24 hours after the reaction, and removing the 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride, the N-hydroxysuccinimide and unreacted polyethylene glycol with amino at the end group; then freeze-drying at-50 ℃ to obtain modified silk fibroin;

(2) The laccase catalyzes pyrrole self-polymerization and silk fibroin graft polymerization: adding laccase into the silk fibroin and pyrrole mixed solution modified in the step (1) to catalyze self-polymerization of pyrrole and graft polymerization of pyrrole and silk fibroin molecules;

(3) Forming a flexible conductive film silk fibroin film: pouring the mixed solution treated in the step (2) into a polytetrafluoroethylene mold, and drying and molding at 25 ℃.

In the step (1), the reaction formula comprises: 20-40 g/L of silk fibroin, 5-10 g/L of polyethylene glycol with molecular weight of 400-600 and amino-containing terminal group, 2.5-5 g/L of 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride and 2.5-5 g/L of N-hydroxysuccinimide; reaction conditions are as follows: the pH value is 5-7, the temperature is 25-40 ℃, and the time is 4-24 hours;

In the step (2), the reaction formula comprises: 20-40 g/L of pyrrole, 20-40 g/L of modified silk fibroin and 0.2-1U/mL of laccase; reaction conditions are as follows: the pH value is 4.5-6, the temperature is 25-50 ℃, and the time is 8-12 hours.

the hyaluronic acid-based conductive film material prepared by the method for preparing the hyaluronic acid-based conductive film material by the enzymic method is within the protection scope of the invention.

has the advantages that:

Compared with the preparation of the flexible conductive fibroin membrane material by a blending method or a chemical initiation method, the invention has the following advantages:

(1) the enzyme catalysis efficiency is high, laccase can catalyze intermolecular crosslinking of silk fibroin and increase the strength of a silk fibroin membrane material, and can catalyze pyrrole polymerization to promote the graft polymerization of tyrosine and pyrrole in silk fibroin and increase the conductive effect of the silk fibroin membrane, and the enzymatic reaction has the advantages of strong specificity and high reaction efficiency;

(2) The reaction condition is mild, under the low-temperature and near-neutral condition, the PEG containing amino is grafted for silk fibroin molecular modification, after the residual low-molecular reactant is removed by dialysis, the pyrrole polymerization is catalyzed by an enzyme method, the silk fibroin film is endowed with conductivity, and the adverse effect of the chemical cross-linking agent and the chemical initiator residue on the biological safety of the film material is avoided;

(3) the mechanical property and the conductivity are obviously improved, the laccase can catalyze the silk fibroin cross-linking and the silk fibroin and pyrrole graft polymerization, the breaking strength and the breaking elongation of the membrane material are increased, and better flexibility is obtained; after being soaked in water, the membrane material still has better flexibility and conductive effect.

Detailed Description

A method for preparing flexible conductive silk fibroin membrane material by enzyme method comprises grafting polyethylene glycol with amino group at terminal group onto silk fibroin molecule by 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide; then, the conductive silk fibroin membrane material is prepared by catalyzing and oxidizing pyrrole self-polymerization and pyrrole and silk fibroin molecule graft polymerization by virtue of laccase. The specific embodiment is as follows: