CN107412882A - A kind of preparation method for attaching flexible artificial skin receptor - Google Patents

Abstract

The invention relates to the field of artificial skin, and discloses a preparation method for attaching breathable artificial skin receptors, comprising: (1) preparing polyvinyl alcohol solution; (2) preparing silk fibroin solution; (3) preparing silk fibroin-polyvinyl alcohol solution; (4) anti-adhesive treatment; (5) spin-coating silk fibroin-polyvinyl alcohol solution to form a film; (6) peeling off the film and drying-absorbing repeated treatment; (7) silver-loaded graphene; (8) centrifugation, Vacuum drying; (9) the graphene-silver nanocomposite is plated on the base film by vapor deposition. The artificial skin of the invention has good biocompatibility function, can change resistance under certain external force, and has good physical and mechanical properties. When in use, attach the non-plated surface to the skin, dissolve polyvinyl alcohol with a small amount of water and moisten the silk fibroin, so that the conductive material is closely attached to the skin surface, and due to the addition of additives and the transformation of the silk fibroin structure, it is tightly attached While ensuring flexibility and toughness.

Description

A preparation method for attaching flexible artificial skin receptors

technical field

The invention relates to the field of artificial skin, in particular to a preparation method for attaching flexible artificial skin receptors.

technical background

Artificial skin is a dressing used to treat skin wounds, which is mainly made of biomaterials or synthetic materials with good biocompatibility. Artificial skin has a good effect on scalds, burns and skin loss in the medical field, and can even be used as a substitute for natural skin in some cases. The artificial skin that has been successfully developed and applied at present mainly plays a role of covering the subcutaneous tissue to a certain extent, provides a composite material scaffold that promotes the growth of wound epidermal cells, or has some slow-release drug factors that can promote skin growth. This type of artificial skin has good biocompatibility, physical and mechanical properties and medical performance, but its production is complicated, the cost is high, and it does not have the tactile sensation and signal transmission function of natural skin.

The artificial skin receptor is a membranous composite material with external stimulus perception function and electrical signal transmission function added on the basis of the original artificial skin. Such receptors have a certain sensing function for changes and stimuli in the external environment, such as thermoreceptors can sense changes in skin temperature, and tactile receptors can sense skin deformation under external force. However, the common problems existing in artificial skin receptors at present are discomfort caused by contact with the human body and physical and mechanical properties that do not meet the requirements for use.

Contents of the invention

In order to solve the above technical problems, the present invention provides a preparation method for attaching flexible artificial skin receptors. The invention uses silk fibroin protein with good biocompatibility and polyvinyl alcohol with good water solubility as substrates, and a layer of conductive material is plated on one side by gas phase deposition. Silk fibroin can promote the growth of wound epidermal cells. Graphene and silver nanometers have excellent electrical conductivity and electrochemical sensitivity, and can change the size of resistance under external force. Among them, Ag particles have good antibacterial effect. When in use, water dissolves polyvinyl alcohol and moistens silk fibroin, so that the conductive material is closely attached to the skin surface. Due to the existence of the toughening material and the transformation of the crystal structure of silk fibroin, the softness and flexibility are guaranteed while being tightly attached. Toughness, which overcomes the common problems of traditional artificial skin receptors.

The specific technical solution of the present invention is: a preparation method for attaching flexible artificial skin receptors, comprising the following steps:

(1) Take polyvinyl alcohol and heat it to dissolve into an aqueous solution, stir to make it completely dissolve, add ethanol to obtain a polyvinyl alcohol solution.

The addition of ethanol can change the surface tension of the solution and improve the film-forming performance of the solution.

(2) Extract silk fibroin and prepare silk fibroin solution.

(3) Stir the silk fibroin solution and polyvinyl alcohol solution, add glycerin and glutaraldehyde dropwise, mix and sonicate to form a uniform silk fibroin-polyvinyl alcohol mixed solution.

Glycerol is added as a toughening agent, which can improve the toughness of the product. Glutaraldehyde is added as a cross-linking agent, which can promote the cross-linking of silk fibroin and improve product strength.

(4) Anti-adhesive treatment of the substrate silicon base: place the monocrystalline silicon wafer in an evaporating dish, add trimethylchlorosilane liquid, close the evaporating dish, and evaporate in it for 8-12 minutes to make a non-stick layer.

(5) The silk fibroin-polyvinyl alcohol mixed solution is formed into a base film by a spin coating method, and dried as a conductive intermediate layer.

(6) Remove the formed base film under the condition of water vapor, dry at 40°C-80°C and absorb moisture at room temperature for 3-5 times.

Repeated moisture absorption and desorption can change the crystal structure of silk fibroin film, effectively improving the strength and stability of silk fibroin film.

( ₇ ) Disperse graphene in deionized water, add AgNO solution drop by drop under ultrasonic conditions, after reacting for a period of time, adjust the pH value of the solution to 11-12 by adding NaOH solution, and then put the mixed solution in oil Reaction in the bath.

(8) After the reaction, the mixed solution was centrifuged to obtain the precipitate, then centrifugally washed with absolute ethanol and deionized water respectively, and vacuum-dried to obtain the graphene-silver nanocomposite material.

The addition of Ag nanoparticles can improve the antibacterial performance and electrochemical sensitivity of the material.

(9) The graphene-silver nanocomposite material is plated on the treated basement membrane by a vapor phase deposition method to obtain an attached flexible artificial skin sensor. The graphene-silver nanocomposite material is plated on one side of the nano-silk fibroin PVA fiber sample by vapor deposition method to obtain a breathable artificial skin sensor. When using, attach the non-plated side to the skin, dissolve the PVA with a small amount of water and moisten it Silk fibroin makes the conductive material adhere closely to the skin surface, and due to the existence of the toughening material and the transformation of the crystal structure of silk fibroin, softness and toughness are ensured while being closely adhered.

The artificial skin of the present invention adopts the method of plating conductive material on the porous film by vapor phase deposition on one side. When in use, the non-plated side is attached to the skin, and a small amount of water is used to dissolve PVA and moisten silk fibroin, so that the conductive material is closely attached to the skin surface. , and due to the existence of toughening materials and the transformation of the crystal structure of silk fibroin, softness and toughness are guaranteed while being closely attached,

In the invention, silk fibroin-polyvinyl alcohol nanofibers formed by spin coating are used as the base skeleton, and graphene and nano silver are used as conductive materials. Ag and graphene have good electrochemical properties, silk fibroin has excellent biocompatibility, and the existence of toughening materials and the transformation of the crystal structure of silk fibroin have excellent strength and tensile properties within a certain range. Compared with the prior art, the method has little environmental pollution and simple preparation method. The manufactured artificial skin receptor has the advantages of promoting wound healing, external force response and good physical and mechanical properties.

As a preference, in step (1), the degree of alcoholysis of polyvinyl alcohol is less than 88% mole fraction, the heating temperature is less than 40°C, the concentration of polyvinyl alcohol solution is 6wt%-10wt%, and the amount of ethanol added is 0.5wt%-5wt %.

Preferably, in step (2), the silk fibroin is obtained through degumming, enzymatic hydrolysis in ionic liquid, dialysis and freeze-drying. Specifically preferably:

A) Weigh 4g of mulberry silk as a sample, wash it with deionized water, remove surface pollutants, and dry it.

B) The dried sample was boiled in a mixed solution containing 0.5% Na ₂ PO ₄ and 1% C ₁₇ H ₃₅ COONa for 30 minutes at a bath ratio of 1:100 to perform degumming treatment, and degummed twice in total.

C) After degumming, wash the sample with deionized water for more than 4 times, and put it in a 60°C oven to obtain dried silk fibroin fibers.

D) Weigh 2g of dried silk fibroin fiber, immerse it in ionic liquid at a bath ratio of 1:40, add 0.15g of PEG-alkaline protease powder at the same time, stir in an oil bath at 40°C for 6h, and obtain silk fibroin/ionic liquid After solution, incubate in an oil bath above 80°C for at least 30 minutes to inactivate the enzyme.

E) After the silk fibroin/ionic liquid solution is cooled to room temperature, add absolute ethanol and soak repeatedly, and the silk fibroin will precipitate out. The mixture is subjected to vacuum filtration, deionized water is added to the filtered silk fibroin, soaked repeatedly and then filtered, and then the solution is put into a dialysis bag with a molecular weight cut-off of 7000-10000 for dialysis for 24 hours to obtain a pure silk fibroin solution.

F) freeze-drying the obtained silk fibroin solution to obtain silk fibroin powder.

Among them, the preparation of PEG-alkaline protease: Weigh 0.15g of alkaline protease, 0.17g of PEG (1000MW polyethylene glycol), 0.16g of K ₂ HPO ₄ (dipotassium hydrogen phosphate), dissolve in 10mL of deionized water, 40 Incubate at -20°C for 2 hours, then freeze at -20°C for 4 hours, and freeze-dry for 96 hours to obtain PEG-alkaline protease powder for use.

Preparation of ionic liquid: In a 250mL three-necked flask, add 137mL 2-methallyl chloride and 80mL N-methylimidazole, stir and reflux in an oil bath at 80°C for 3h, after the reaction is complete, use rotary evaporation to remove excess 2 -Methallyl chloride to obtain a light yellow transparent liquid, namely 1-(2-methyl)allyl-3-methylimidazolium chloride ionic liquid, freeze-dried for 24 hours, and thawed for use.

In the preparation process of silk fibroin, the present invention utilizes PEG 1000 to modify alkaline protease, and utilizes the affinity of PEG to ionic liquid, which not only improves the stability and reactivity of the enzyme, but also increases the activity of the enzyme in the ionic liquid. The uniformity of dispersion is beneficial to its hydrolysis of silk fibroin. In the degumming process of the present invention, C ₁₇ H ₃₅ COONa is added as a buffer to maintain an alkaline environment, improve degumming efficiency, and reduce damage to silk fibers at the same time. The invention utilizes the dual dissolving effect of biological enzyme and ionic liquid to treat the silk fibroin at the same time, thereby improving the solubility of the silk fibroin. In the present invention, the biological enzyme is non-toxic and harmless, friendly to the environment, and at the same time, the dosage is small, saving resources; the specificity is high, the action condition is mild, and the damage to the silk fibroin is small. The ionic liquid is a "green solvent", which is environmentally friendly and harmless. The group can be designed, and it is easy to recover and can be recycled.

As a preference, in step (3), the silk fibroin solution and the polyvinyl alcohol solution need to be stirred and mixed at 20°C-40°C, the stirring rate is 500r/min-1500r/min, the stirring time is 60min-120min, and the glycerol The addition amount is 0.2wt%-1wt%, and the addition amount of glutaraldehyde is 0.2wt%-1wt%.

Preferably, in step (5), the silk fibroin-polyvinyl alcohol mixed solution needs to be subjected to ultrasonic vibration treatment for 20 minutes, and a film is formed by a freeze-drying method.

Ultrasonic vibration can promote the dispersion of silk fibroin, and combined with freeze-drying and compression treatment, the formed silk fibroin film can have good porosity and improve the air permeability of the silk fibroin film.

Preferably, in step (5), the base film needs to be post-treated, and the treatment method is to treat the dried nanofiber sample under 1 MPa pressure for 10-30 min.

Compression treatment can improve the mechanical properties of the membrane, so that it has good strength.

Preferably, in step (7), the graphene is obtained by vapor phase deposition or mechanical exfoliation.

The present invention aims to obtain reduced graphene with better conductivity. The graphene is not graphene oxide prepared by a redox method, but is obtained by a vapor phase deposition method or a mechanical exfoliation method.

As preferably, in step (7), the concentration of the graphene dispersion is 0.1-1mol/L, the concentration of AgNO3 solution is _0.1-1mol /L, and the volume ratio of dropping is 0.5-2; NaOH solution is 0.1 mol/L, the oil bath temperature is 40°C-80°C, and the reaction time is 20-50min.

As a preference, in step (8), the conditions for centrifugation and washing are 2-5 times of centrifugation at 3000-8000rmp, each time of centrifugation for 2-5min.

As preferably, in step (9), the gas phase deposition condition is that the graphene gas is diluted to 2% with argon, the flow rate is controlled at 100-250mL/min, the growth temperature is 100-200°C, the reaction pressure is 50-100Pa, and the growth time 1-6min.

Compared with prior art, the beneficial effect of the present invention is:

(1) The present invention adopts waste silk as a raw material, realizes the recycling of waste materials, and reduces the experiment cost.

(2) The present invention adopts the method of compounding polyvinyl alcohol and silk fibroin and plating conductive materials, and the product has the performance of promoting wound healing, good external force response performance and air-permeable adhesion performance at the same time.

(3) The present invention utilizes the electrochemical sensitivity of silver nanoparticles, and the product responds sensitively to external forces.

(4) The present invention uses less chemicals, and the experimental process is environmentally friendly.

detailed description

The present invention will be further described below in conjunction with embodiment.

Example 1

A preparation method for attaching a flexible artificial skin receptor, adopting the following steps:

(1) Take polyvinyl alcohol and heat it to dissolve into 6wt% aqueous solution, stir for 30min to make it dissolve completely, add each 0.5wt% ethanol to form a mixed solution; wherein, the degree of alcoholysis of polyvinyl alcohol is less than 88% mole fraction, and the heating temperature is less than 40°C.

(2) Extraction of silk fibroin:

A) Weigh 4g of mulberry silk as a sample, wash it with deionized water, remove surface pollutants, and dry it.

B) The dried sample was boiled in a mixed solution containing 0.5% Na ₂ PO ₄ and 1% C ₁₇ H ₃₅ COONa for 30 minutes at a bath ratio of 1:100 to perform degumming treatment, and degummed twice in total.

C) After degumming, wash the sample with deionized water for more than 4 times, and put it in a 60°C oven to obtain dried silk fibroin fibers.

D) Weigh 2g of dried silk fibroin fiber, immerse it in ionic liquid at a bath ratio of 1:40, add 0.15g of PEG-alkaline protease powder at the same time, stir in an oil bath at 40°C for 6h, and obtain silk fibroin/ionic liquid After solution, incubate in an oil bath above 80°C for at least 30 minutes to inactivate the enzyme.

E) After the silk fibroin/ionic liquid solution is cooled to room temperature, add absolute ethanol and soak repeatedly, and the silk fibroin will precipitate out. The mixture is subjected to vacuum suction filtration, deionized water is added to the filtered silk fibroin, soaked repeatedly and filtered, and then the solution is put into a dialysis bag with a molecular weight cut-off of 8000 and dialyzed for 24 hours to obtain a pure silk fibroin solution.

F) freeze-drying the obtained silk fibroin solution to obtain silk fibroin powder.

Among them, the preparation of PEG-alkaline protease: Weigh 0.15g of alkaline protease, 0.17g of PEG (1000MW polyethylene glycol), 0.16g of K ₂ HPO ₄ (dipotassium hydrogen phosphate), dissolve in 10mL of deionized water, 40 Incubate at -20°C for 2 hours, then freeze at -20°C for 4 hours, and freeze-dry for 96 hours to obtain PEG-alkaline protease powder for use.

Preparation of ionic liquid: In a 250mL three-necked flask, add 137mL 2-methallyl chloride and 80mL N-methylimidazole, stir and reflux in an oil bath at 80°C for 3h, after the reaction is complete, use rotary evaporation to remove excess 2 -Methallyl chloride to obtain a light yellow transparent liquid, namely 1-(2-methyl)allyl-3-methylimidazolium chloride ionic liquid, freeze-dried for 24 hours, and thawed for use.

The silk fibroin was prepared as a 10wt% silk fibroin solution.

(3) Stir the silk fibroin solution and the polyvinyl alcohol solution at 20°C for 60 minutes at a stirring rate of 1000r/min, add 0.2wt% glycerol and glutaraldehyde dropwise and mix ultrasonically to form a uniform silk fibroin-polyvinyl alcohol mixed solution ;

(4) Anti-adhesive treatment is carried out on the substrate silicon base used in the multilayer composite artificial skin, the single crystal silicon wafer is placed in an evaporating dish, a small amount of trimethylchlorosilane liquid is added, the evaporating dish is closed, and the evaporating dish is evaporated for 10 minutes. to make the non-stick layer;

(5) The silk fibroin-polyvinyl alcohol mixed solution is formed into a base film by spin coating, and then freeze-dried as a conductive intermediate layer; wherein, the silk fibroin-polyvinyl alcohol mixed solution needs to be subjected to ultrasonic vibration treatment for 20 minutes, and is formed by freeze-drying method. membrane. The base film needs to be post-treated, and the treatment method is to process the dried nanofiber sample under 1 MPa pressure for 20 minutes.

(6) Remove the formed base film under the condition of water vapor, and dry it at 60°C and absorb moisture at room temperature for 3-5 times;

( ₇ ) Graphene is dispersed in deionized water, and AgNO solution is added dropwise under ultrasonic conditions, after a period of reaction, the pH value of the solution is adjusted to 11-12 by adding NaOH solution, and then the mixed solution is Reaction under an oil bath; wherein, the graphene is obtained by a vapor phase deposition method or a mechanical exfoliation method. The concentration of the graphene dispersion is 0.5mol/L, the concentration _of the AgNO solution is 0.5mol/L, and the volume ratio of the dropwise addition is 1; the NaOH solution is 0.1mol/L, the oil bath temperature is 60°C, and the reaction time for 35min.

(8) After the reaction, the mixed solution was centrifuged to obtain the precipitate, and then centrifuged and washed with absolute ethanol and deionized water respectively. The conditions of centrifuged washing were centrifuged at 5000rmp for 3 times, each centrifuged for 3 minutes. Vacuum drying obtains graphene-silver nanocomposite material;

(9) The graphene-silver nanocomposite material is plated on the treated basement membrane by a vapor phase deposition method to obtain an attached flexible artificial skin sensor. Among them, the gas phase deposition conditions are that the graphene gas is diluted to 2% with argon, the flow rate is controlled at 180mL/min, the growth temperature is 150°C, the reaction pressure is 75Pa, and the growth time is 3min.

Example 2

A preparation method for attaching a flexible artificial skin receptor, adopting the following steps:

(1) Heat and dissolve polyvinyl alcohol into an 8wt% aqueous solution, stir for 40 minutes to make it completely dissolve, add each 0.2wt% ethanol to form a mixed solution; wherein, the degree of alcoholysis of polyvinyl alcohol is less than 88% by mole fraction, and the heating temperature is less than 40°C.

(2) Extraction of silk fibroin:

A) Weigh 4g of mulberry silk as a sample, wash it with deionized water, remove surface pollutants, and dry it.

B) The dried sample was boiled in a mixed solution containing 0.5% Na ₂ PO ₄ and 1% C ₁₇ H ₃₅ COONa for 30 minutes at a bath ratio of 1:100 to perform degumming treatment, and degummed twice in total.

C) After degumming, wash the sample with deionized water for more than 4 times, and put it in a 60°C oven to obtain dried silk fibroin fibers.

D) Weigh 2g of dried silk fibroin fiber, immerse it in ionic liquid at a bath ratio of 1:40, add 0.15g of PEG-alkaline protease powder at the same time, stir in an oil bath at 40°C for 6h, and obtain silk fibroin/ionic liquid After solution, incubate in an oil bath above 80°C for at least 30 minutes to inactivate the enzyme.

E) After the silk fibroin/ionic liquid solution is cooled to room temperature, add absolute ethanol and soak repeatedly, and the silk fibroin will precipitate out. The mixture is subjected to vacuum suction filtration, deionized water is added to the filtered silk fibroin, soaked repeatedly and filtered, and then the solution is put into a dialysis bag with a molecular weight cut-off of 8000 and dialyzed for 24 hours to obtain a pure silk fibroin solution.

F) freeze-drying the obtained silk fibroin solution to obtain silk fibroin powder.

Among them, the preparation of PEG-alkaline protease: Weigh 0.15g of alkaline protease, 0.17g of PEG (1000MW polyethylene glycol), 0.16g of K ₂ HPO ₄ (dipotassium hydrogen phosphate), dissolve in 10mL of deionized water, 40 Incubate at -20°C for 2 hours, then freeze at -20°C for 4 hours, and freeze-dry for 96 hours to obtain PEG-alkaline protease powder for use.

Preparation of ionic liquid: In a 250mL three-necked flask, add 137mL 2-methallyl chloride and 80mL N-methylimidazole, stir and reflux in an oil bath at 80°C for 3h, after the reaction is complete, use rotary evaporation to remove excess 2 -Methallyl chloride to obtain a light yellow transparent liquid, namely 1-(2-methyl)allyl-3-methylimidazolium chloride ionic liquid, freeze-dried for 24 hours, and thawed for use.

The silk fibroin was prepared as a 10wt% silk fibroin solution.

(3) Stir the silk fibroin solution and the polyvinyl alcohol solution at 20°C for 80 min at a stirring rate of 500 r/min, add 0.4wt% glycerin and glutaraldehyde dropwise and mix ultrasonically to form a uniform silk fibroin-polyvinyl alcohol mixed solution ;

(4) Anti-adhesive treatment is carried out on the substrate silicon base used in the multilayer composite artificial skin, the single crystal silicon wafer is placed in an evaporating dish, a small amount of trimethylchlorosilane liquid is added, the evaporating dish is closed, and the evaporating dish is evaporated for 10 minutes. to make the non-stick layer;

(5) The silk fibroin-polyvinyl alcohol mixed solution is formed into a base film by spin coating, and then freeze-dried as a conductive intermediate layer; wherein, the silk fibroin-polyvinyl alcohol mixed solution needs to be subjected to ultrasonic vibration treatment for 20 minutes, and is formed by freeze-drying method. membrane. The base film needs to be post-treated, and the treatment method is to process the dried nanofiber sample under 1 MPa pressure for 10 minutes.

(6) Remove the formed base film under the condition of water vapor, dry at 40°C and absorb moisture at room temperature for 3 times;

( ₇ ) Graphene is dispersed in deionized water, and AgNO solution is added dropwise under ultrasonic conditions, after a period of reaction, the pH value of the solution is adjusted to 11-12 by adding NaOH solution, and then the mixed solution is Reaction under an oil bath; wherein, the graphene is obtained by a vapor phase deposition method or a mechanical exfoliation method. The concentration of the graphene dispersion is 0.1mol/L, the concentration _of the AgNO solution is 0.1mol/L, and the volume ratio of the dropwise addition is 0.5; the NaOH solution is 0.1mol/L, the oil bath temperature is 40°C, and the reaction time for 50min.

(8) After the reaction, the mixed solution was centrifuged to obtain the precipitate, and then centrifuged and washed with absolute ethanol and deionized water respectively. The condition of the centrifuged washing was to centrifuge 5 times at 3000rmp, and centrifuge for 2min each time. Vacuum drying obtains graphene-silver nanocomposite material;

(9) The graphene-silver nanocomposite material is plated on the treated basement membrane by a vapor phase deposition method to obtain an attached flexible artificial skin sensor. Among them, the gas phase deposition conditions were that the graphene gas was diluted to 2% with argon, the flow rate was controlled at 100 mL/min, the growth temperature was 100 °C, the reaction pressure was 50 Pa, and the growth time was 1 min.

Example 3

A preparation method for attaching a flexible artificial skin receptor, adopting the following steps:

(1) Heat and dissolve polyvinyl alcohol into a 10wt% aqueous solution, stir for 60 minutes to make it completely dissolve, add 1wt% ethanol each to form a mixed solution; wherein, the degree of alcoholysis of polyvinyl alcohol is less than 88% by mole fraction, and the heating temperature is less than 40 ℃.

(2) Extraction of silk fibroin:

A) Weigh 4g of mulberry silk as a sample, wash it with deionized water, remove surface pollutants, and dry it.

B) The dried sample was boiled in a mixed solution containing 0.5% Na ₂ PO ₄ and 1% C ₁₇ H ₃₅ COONa for 30 minutes at a bath ratio of 1:100 to perform degumming treatment, and degummed twice in total.

C) After degumming, wash the sample with deionized water for more than 4 times, and put it in a 60°C oven to obtain dried silk fibroin fibers.

D) Weigh 2g of dried silk fibroin fiber, immerse it in ionic liquid at a bath ratio of 1:40, add 0.15g of PEG-alkaline protease powder at the same time, stir in an oil bath at 40°C for 6h, and obtain silk fibroin/ionic liquid After solution, incubate in an oil bath above 80°C for at least 30 minutes to inactivate the enzyme.

E) After the silk fibroin/ionic liquid solution is cooled to room temperature, add absolute ethanol and soak repeatedly, and the silk fibroin will precipitate out. The mixture is subjected to vacuum suction filtration, deionized water is added to the filtered silk fibroin, soaked repeatedly and filtered, and then the solution is put into a dialysis bag with a molecular weight cut-off of 8000 and dialyzed for 24 hours to obtain a pure silk fibroin solution.

F) freeze-drying the obtained silk fibroin solution to obtain silk fibroin powder.

Among them, the preparation of PEG-alkaline protease: Weigh 0.15g of alkaline protease, 0.17g of PEG (1000MW polyethylene glycol), 0.16g of K ₂ HPO ₄ (dipotassium hydrogen phosphate), dissolve in 10mL of deionized water, 40 Incubate at -20°C for 2 hours, then freeze at -20°C for 4 hours, and freeze-dry for 96 hours to obtain PEG-alkaline protease powder for use.

Preparation of ionic liquid: In a 250mL three-necked flask, add 137mL 2-methallyl chloride and 80mL N-methylimidazole, stir and reflux in an oil bath at 80°C for 3h, after the reaction is complete, use rotary evaporation to remove excess 2 -Methallyl chloride to obtain a light yellow transparent liquid, namely 1-(2-methyl)allyl-3-methylimidazolium chloride ionic liquid, freeze-dried for 24 hours, and thawed for use.

The silk fibroin was prepared as a 10wt% silk fibroin solution.

(3) Stir the silk fibroin solution and the polyvinyl alcohol solution at 30°C for 90 minutes at a stirring rate of 1500r/min, add 0.5wt% glycerol and glutaraldehyde dropwise and mix ultrasonically to form a uniform silk fibroin-polyvinyl alcohol mixed solution ;

(4) Anti-adhesive treatment is carried out on the substrate silicon base used in the multilayer composite artificial skin, the single crystal silicon wafer is placed in an evaporating dish, a small amount of trimethylchlorosilane liquid is added, the evaporating dish is closed, and the evaporating dish is evaporated for 10 minutes. to make the non-stick layer;

(5) The silk fibroin-polyvinyl alcohol mixed solution is formed into a base film by spin coating, and then freeze-dried as a conductive intermediate layer; wherein, the silk fibroin-polyvinyl alcohol mixed solution needs to be subjected to ultrasonic vibration treatment for 20 minutes, and is formed by freeze-drying method. membrane. The base film needs to be post-treated, and the treatment method is to process the dried nanofiber sample under 1 MPa pressure for 30 minutes.

(6) Remove the formed base film under water vapor conditions, dry at 40°C-80°C and absorb moisture at room temperature for 3-5 times;

( ₇ ) Graphene is dispersed in deionized water, and AgNO solution is added dropwise under ultrasonic conditions, after a period of reaction, the pH value of the solution is adjusted to 11-12 by adding NaOH solution, and then the mixed solution is Reaction under an oil bath; wherein, the graphene is obtained by a vapor phase deposition method or a mechanical exfoliation method. The concentration of the graphene dispersion is 1mol/L, the concentration _of the AgNO solution is 1mol/L, and the volume ratio of the dropwise addition is 2; the NaOH solution is 0.1mol/L, the oil bath temperature is 80°C, and the reaction time is 20min .

(8) After the reaction, the mixed solution was centrifuged to obtain the precipitate, and then centrifuged and washed with absolute ethanol and deionized water respectively. The condition of the centrifuged washing was to centrifuge twice at 8000rmp for 5 minutes each time. Vacuum drying obtains graphene-silver nanocomposite material;

(9) The graphene-silver nanocomposite material is plated on the treated basement membrane by a vapor phase deposition method to obtain an attached flexible artificial skin sensor. Among them, the gas phase deposition conditions are that the graphene gas is diluted to 2% with argon, the flow rate is controlled at 250mL/min, the growth temperature is 200°C, the reaction pressure is 100Pa, and the growth time is 6min.

Raw materials used in the present invention, equipment, if not specified, are commonly used raw materials, equipment in this area; Method used in the present invention, if not specified, are conventional methods in this area.

The above are only preferred embodiments of the present invention, and do not limit the present invention in any way. All simple modifications, changes and equivalent transformations made to the above embodiments according to the technical essence of the present invention still belong to the technical solution of the present invention. scope of protection.

Claims (10)

1. a kind of preparation method for attaching flexible artificial skin receptor, it is characterised in that comprise the following steps：

(1) take polyvinyl alcohol to dissolve by heating to be allowed to be completely dissolved into the aqueous solution, stirring, add ethanol and obtain poly-vinyl alcohol solution；

(2) fibroin is extracted, and prepares silk fibroin solution；

(3) stirred with silk fibroin solution and poly-vinyl alcohol solution, glycerine and glutaraldehyde mixing ultrasound is added dropwise, forms uniform silk Element-polyvinyl alcohol solution；

(4) release treatment is carried out to substrate silicon substrate：Monocrystalline silicon piece is positioned in evaporating dish, adds trim,ethylchlorosilane liquid, Closed evaporating ware, 8-12min is evaporated wherein and is used for doing antistick layer；

(5) spin-coating method is utilized, as the intermediate layer of conduction, to be dried into basilar memebrane fibroin-polyvinyl alcohol solution；

(6) basilar memebrane of forming is taken off under the conditions of water vapour, and the moisture absorption weight under 40 DEG C of -80 DEG C of dryings and room temperature condition Handle 3-5 times again；

(7) take graphene dispersion that AgNO is added dropwise dropwise under ultrasound condition in deionized water₃Solution, after reacting a period of time, The pH value of solution is adjusted to 11-12 by adding NaOH solution, then reacts mixed liquor under oil bath；

(8) after reaction terminates, mixed liquor is centrifuged into taking precipitate, then distinguishes centrifuge washing with absolute ethyl alcohol, deionized water, very Sky is dried to obtain graphene-argentum nano composite material；

(9) graphene-argentum nano composite material is plated on treated basilar memebrane using vapour deposition process, obtains attaching flexibility Artificial skin receptor.

A kind of 2. preparation method for attaching flexible artificial skin receptor as claimed in claim 1, it is characterised in that step (1) in, the alcoholysis degree of polyvinyl alcohol is less than molar fraction 88%, and heating-up temperature is less than 40 DEG C, and poly-vinyl alcohol solution concentration exists 6wt%-10wt%, the amount that ethanol adds is 0.5wt%-5wt%.

A kind of 3. preparation method for attaching flexible artificial skin receptor as claimed in claim 1, it is characterised in that step (2) in, the fibroin is made by enzymolysis, dialysis, freeze-drying in degumming, ionic liquid.

A kind of 4. preparation method for attaching flexible artificial skin receptor as claimed in claim 1, it is characterised in that step (3) in, silk fibroin solution need to be stirred at 20 DEG C -40 DEG C with poly-vinyl alcohol solution and mix, stir speed (S.S.) 500r/min- 1500r/min, mixing time 60min-120min, the addition of glycerine is 0.2wt%-1wt%, and the addition of glutaraldehyde is 0.2wt%-1wt%。

A kind of 5. preparation method for attaching flexible artificial skin receptor as claimed in claim 1, it is characterised in that step (5) in, fibroin-polyvinyl alcohol solution need to pass through ultrasonic vibration processing 20min, and utilize freeze-drying film forming.

A kind of 6. preparation method of attaching flexibility artificial skin receptor as described in claim 1 or 5, it is characterised in that step Suddenly in (5), the basilar memebrane need to pass through post processing, and processing method is, by dried nanofiber sample under 1MPa air pressure Handle 10-30min.

A kind of 7. preparation method for attaching flexible artificial skin receptor as claimed in claim 1, it is characterised in that step (7) in, the graphene is obtained by vapour deposition process or mechanical stripping method.

A kind of 8. preparation method of attaching flexibility artificial skin receptor as described in claim 1 or 7, it is characterised in that step Suddenly in (7), the concentration of the graphene dispersing solution is 0.1-1mol/L, AgNO₃The concentration of solution is 0.1-1mol/L, dropwise addition Volume ratio is 0.5-2；NaOH solution is 0.1mol/L, and oil bath temperature is 40 DEG C -80 DEG C, reaction time 20-50min.

A kind of 9. preparation method for attaching flexible artificial skin receptor as claimed in claim 1, it is characterised in that step (8) in, the condition of centrifuge washing centrifuges 2-5 times for 3000-8000rmp, centrifuges 2-5min every time.

A kind of 10. preparation method for attaching flexible artificial skin receptor as claimed in claim 1, it is characterised in that step (9) in, vapor deposition conditions are graphene gas argon-dilution to 2%, and flow is controlled in 100-250mL/min, growth temperature For 100-200 DEG C, reaction pressure 50-100Pa, growth time 1-6min.