CN111647176B - Preparation method of sericin microspheres - Google Patents
Preparation method of sericin microspheres Download PDFInfo
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- CN111647176B CN111647176B CN202010459658.4A CN202010459658A CN111647176B CN 111647176 B CN111647176 B CN 111647176B CN 202010459658 A CN202010459658 A CN 202010459658A CN 111647176 B CN111647176 B CN 111647176B
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
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- C08J2389/00—Characterised by the use of proteins; Derivatives thereof
Abstract
The invention discloses a preparation method of sericin microspheres. The invention takes soluble sericin as a raw material, and the stable sericin microspheres are obtained by dissolving the soluble sericin in water, sequentially carrying out solvent replacement, chemical crosslinking and solvent heat treatment, and carrying out centrifugal washing and vacuum drying. The method is simple and efficient, and is particularly suitable for preparing the sericin nano-microspheres from the sericin aqueous solution. The sericin microspheres with controllable particle size, good dispersibility and good stability are prepared by sericin, so that the damage of sericin wastewater to the natural environment can be reduced, the residual value of sericin wastewater is fully utilized, the application of sericin in different fields is expanded, and the sericin microspheres have important practical significance for protecting the environment and increasing the economic benefit.
Description
Technical Field
The invention relates to a preparation method for preparing sericin microspheres, belonging to the technical field of protein nano microspheres.
Background
China is the most important silk producing country in the world, and is at the top of the world in both scale and yield. The natural silk is composed of sericin and fibroin, wherein the sericin accounts for 25-30% of the weight of the silk. Sericin can be further divided into an outer layer (50 wt%), an intermediate layer (35 wt%) and an inner layer (15 wt%) according to the solubility of sericin in water under different temperatures and pressures. Sericin has inferior mechanical properties and is degraded more rapidly than silk fibroin, and thus has not received the same attention for a long period of time. The total amount of sericin produced by degumming every year in China is about 3.5 ten thousand tons, and waste water containing a large amount of sericin is directly discharged, thereby not only causing environmental pollution, but also wasting a large amount of precious sericin resources.
Sericin is a globular protein containing a variety of polypeptides, consisting of 18 amino acids, containing more serine, aspartic acid and glycine. The primary secondary structure of sericin is mainly random coil with only a very small amount of alpha helix or beta turn. Sericin has good water solubility because it is rich in polar amino acids.
Because of good water solubility and excellent biocompatibility of sericin, sericin is mainly applied to the fields of textile finishing, cosmetics, skin care products, food and biomedicine in the form of aqueous solution at present, and only a few researches directly utilize sericin as a solid phase. This is because in order to increase the degumming rate of silkworm cocoons during degumming, it is often necessary to degrade sericin having a large molecular weight by alkali treatment, enzymatic hydrolysis, or the like. Although this greatly increases the solubility of sericin in water, it also increases the difficulty of recycling sericin as a solid phase.
In the reprocessing field of sericin, chinese patent (ZL 201210574086. X) "a method for manufacturing tussah silk sericin powder" uses insoluble sericin as a raw material, hydrolyzes the sericin by neutral protease and trypsin, and then carries out ultrafiltration separation and H 2 O 2 The soluble sericin powder is prepared by decoloring, evaporation concentration and spray drying, but the appearance and the like of the soluble sericin powder are not represented; a method for preparing sericin spherical microcapsules in Chinese patent (ZL 201410019276.4) takes soluble sericin as a raw material, prepares stable sericin spherical microcapsules in an aqueous solvent by a metal ion chelation method, and characterizes the morphology and biocompatibility of the sericin spherical microcapsules; according to European patent (EP 3112396A 1) "Preparation method and use of serin hydrogel", aqueous solution of LiCl or LiBr is used for dissolving sericin powder, and then the solution is dialyzed to reach a certain concentration and then is chemically crosslinked to prepare sericin hydrogel, and in vitro cell experiments and animal experiments prove that the prepared sericin hydrogel has better stability and biocompatibility; korean patent (KR 101534290B 1) "Silk serin film with good mechanical properties and its preparation method" dissolves sericin under acidic conditions, and dried at room temperature to obtain the toolThe sericin membrane has better mechanical property.
As the most important silk producing countries in China, a large amount of sericin wastewater is generated every year, so that the recovery rate of sericin is improved, diversified sericin products with high added values are prepared, the pressure of the sericin wastewater on the natural environment can be relieved, the sericin is greatly developed and utilized as natural resources, and the sericin production method has profound significance for protecting the environment and increasing the economic benefit.
Disclosure of Invention
In order to overcome the problems of the background art mentioned above, it is an object of the present invention to provide a method for preparing sericin microspheres.
1) Dissolving sericin in deionized water, fully dissolving under magnetic stirring, placing into a centrifuge, centrifuging at a set rotation speed of 8000rpm for 10min, and collecting supernatant to obtain 4wt% sericin water solution;
2) Dissolving 0.48-1.92gF127 in 30mL of absolute ethyl alcohol, controlling the water bath temperature to be 40 ℃, and completely dissolving under magnetic stirring;
3) Taking 3mL of the sericin aqueous solution obtained in the step 1), controlling the water bath temperature to be 40 ℃, setting the mechanical stirring speed to be 500-1500 rpm, and dropwise adding the sericin aqueous solution into the F127/anhydrous ethanol solution obtained in the step 2);
4) Adding 0.3mL5wt% glutaraldehyde/ethanol solution into the sericin suspension obtained in the step 3), controlling the water bath temperature at 40 ℃, and crosslinking for 15min;
5) Pouring the sericin suspension obtained in the step 4) into 50mL of polytetrafluoroethylene lining, packaging into a reaction kettle jacket, quickly placing in a 160-180 ℃ oven, and reacting for 2-8 h;
6) Centrifuging the sericin suspension obtained in the step 5) at 15000rpm for 20min, pouring out the upper liquid, sequentially washing with deionized water and absolute ethyl alcohol, centrifuging for three times, drying the obtained solid in a vacuum oven at 60 ℃ for 12h, and taking out to finally obtain the sericin microspheres.
The molecular weight of the sericin is 16000-20000.
The stabilizer is a triblock copolymer F127, and the mass ratio of sericin to F127 is (1); dropwise adding 4wt% of sericin aqueous solution into F127/anhydrous ethanol by a dropper, wherein the stirring speed is 500-1500 rpm; the temperature of the solvothermal reaction is 160-180 ℃; the solvothermal reaction time is 2-8 h; the rotation speed of the centrifuge is 12000rpm, and the centrifugation time is 20min.
Compared with the background art, the invention has the beneficial effects that:
according to the invention, the sericin microspheres which can be stably and uniformly dispersed in water and have controllable particle size are prepared by using the easily soluble sericin with low molecular weight, so that the application prospects of sericin in different fields are expanded, and the residual value of sericin waste liquid is fully developed; meanwhile, the pressure of sericin wastewater on the natural environment is favorably reduced.
Drawings
FIG. 1 is a graph showing the distribution of the particle size of sericin microspheres prepared in examples 1 to 3. Wherein (a), (b) and (c) correspond to the products obtained in examples 1 to 3, respectively. FIG. 2 is a Fourier transform infrared spectrum of the amide III bands of sericin raw material and sericin microspheres prepared in examples 1 to 3. Wherein (a), (b), (c) and (d) correspond to the sericin raw material and the products obtained in examples 1 to 3, respectively. FIG. 3 is a SEM photograph of sericin microspheres prepared in example 3. Wherein, (a) is a photograph of the sericin microspheres magnified 5 thousand times, and (b) is a photograph of the sericin microspheres magnified 1 thousand times. Fig. 4 is a schematic view of a process for preparing sericin microspheres and a photograph of dispersing the product obtained in example 3 in water.
Detailed Description
The present invention will be further described with reference to the following specific examples.
Example 1:
1) Dissolving sericin in deionized water, fully dissolving under magnetic stirring, putting into a centrifuge, centrifuging at a set rotation speed of 8000rpm for 10min, and taking supernatant to obtain 4wt% sericin aqueous solution;
2) Dissolving 0.48gF127 in 30mL of absolute ethyl alcohol, controlling the water bath temperature to be 40 ℃, and completely dissolving under magnetic stirring;
3) Taking 3mL of the sericin aqueous solution obtained in the step 1), controlling the water bath temperature to be 40 ℃, setting the mechanical stirring speed to be 500rpm, and dropwise adding the sericin aqueous solution into the F127/anhydrous ethanol solution obtained in the step 2);
4) Adding 0.3mL5wt% glutaraldehyde/ethanol solution into the sericin suspension obtained in the step 3), controlling the water bath temperature at 40 ℃, and crosslinking for 15min;
5) Pouring the sericin suspension obtained in the step 4) into 50mL of polytetrafluoroethylene lining, packaging the lining into a reaction kettle, quickly placing the reaction kettle in a drying oven at 180 ℃, and reacting for 2 hours;
6) Centrifuging the sericin suspension obtained in the step 5) for 20min at 12000rpm, pouring out the upper layer liquid, sequentially washing with deionized water and absolute ethyl alcohol, centrifuging for three times, drying the obtained solid in a vacuum oven at 60 ℃ for 12h, and taking out to obtain the sericin microspheres finally.
Example 2:
1) Dissolving sericin in deionized water, fully dissolving under magnetic stirring, placing into a centrifuge, centrifuging at a set rotation speed of 8000rpm for 10min, and collecting supernatant to obtain 4wt% sericin water solution;
2) Dissolving 1.92gF127 in 30mL of absolute ethyl alcohol, controlling the water bath temperature to be 40 ℃, and completely dissolving under magnetic stirring;
3) Taking 3mL of the sericin aqueous solution obtained in the step 1), controlling the water bath temperature to be 40 ℃, setting the mechanical stirring speed to be 1000rpm, and dropwise adding the sericin aqueous solution into the F127/anhydrous ethanol solution obtained in the step 2);
4) Adding 0.3mL5wt% glutaraldehyde/ethanol solution into the sericin suspension obtained in the step 3), controlling the water bath temperature at 40 ℃, and crosslinking for 15min;
5) Pouring the sericin suspension obtained in the step 4) into 50mL of polytetrafluoroethylene lining, packaging the lining into a reaction kettle, quickly placing the reaction kettle in a drying oven at 160 ℃, and reacting for 4 hours;
6) Centrifuging the sericin suspension obtained in the step 5) at 12000rpm for 20min, pouring out the upper solution, sequentially washing with deionized water and absolute ethyl alcohol, centrifuging for three times, drying the obtained solid in a vacuum oven at 60 ℃ for 12h, and taking out to finally obtain the sericin microspheres.
Example 3:
1) Dissolving sericin in deionized water, fully dissolving under magnetic stirring, placing into a centrifuge, centrifuging at a set rotation speed of 8000rpm for 10min, and collecting supernatant to obtain 4wt% sericin water solution;
2) Dissolving 0.96gF127 in 30mL of absolute ethyl alcohol, controlling the temperature of a water bath to be 40 ℃, and completely dissolving under magnetic stirring;
3) Taking 3mL of the sericin aqueous solution obtained in the step 1), controlling the water bath temperature to be 40 ℃, setting the mechanical stirring speed to be 1500rpm, and dropwise adding the sericin aqueous solution into the F127/anhydrous ethanol solution obtained in the step 2);
4) Adding 0.3mL5wt% glutaraldehyde/ethanol solution into the sericin suspension obtained in the step 3), controlling the water bath temperature at 40 ℃, and crosslinking for 15min;
5) Pouring the sericin suspension obtained in the step 4) into a 50mL polytetrafluoroethylene lining, packaging the lining into a reaction kettle, quickly placing the reaction kettle in a drying oven at 170 ℃, and reacting for 8 hours;
6) Centrifuging the sericin suspension obtained in the step 5) for 20min at 12000rpm, pouring out the upper solution, sequentially washing with deionized water and absolute ethyl alcohol, centrifuging for three times, drying the obtained solid in a vacuum oven at 60 ℃ for 12h, and taking out to obtain the sericin microspheres.
The average particle diameter, polydispersity index and particle size distribution of the three sericin microspheres obtained in examples 1 to 3 were measured. Table 1 and FIG. 1 show the results of size characterization of sericin microspheres (a), (b) and (c) prepared in examples 1 to 3. As can be seen from the data in Table 1, the average particle diameters of the sericin microspheres (a), (b) and (c) obtained by the preparation method are 660 nm, 379 nm and 319nm respectively; the polydispersity indexes are 0.176, 0.143 and 0.164 respectively, which indicates that the particle size of the sericin microspheres is relatively uniform. As shown in FIG. 1, the particle size distribution of the prepared sericin microspheres is narrow and all the particles are in a submicron size range. Referring to fig. 2, a fourier infrared spectrum of the amide iii band of the sericin raw material used in the present invention and the sericin microspheres prepared in examples 1 to 3 shows that the secondary conformation of the lyotropic sericin raw material is mainly free of crimping and has only a small amount of α -helix and β -sheet, and the sericin microspheres obtained in the examples have a reduced content of crimping and α -helix conformation and an increased content of β -sheet structure according to different reaction conditions, which is a main reason why the prepared sericin microspheres have good stability in water. As shown in fig. 3, as can be seen from the field emission scanning electron micrograph of the sericin microspheres prepared in example 3, the morphology of the sericin microspheres is close to spherical, and the sericin microspheres have a high specific surface area and polar functional groups with rich surfaces, so that the sericin microspheres are slightly attracted to each other and aggregated during the sample drying process. As shown in fig. 4, it can be seen from the photograph of the sericin microspheres prepared in example 3 dispersed in water that they were uniformly dispersed in water to form a stable suspension, and neither dissolved nor significantly agglomerated in water.
TABLE 1
The foregoing lists merely exemplary embodiments of the invention. The present invention is not limited to the above embodiments, and many variations are possible. All modifications which can be derived or suggested by the person skilled in the art from the present disclosure are to be considered within the scope of the present invention.
Claims (2)
1. A preparation method of sericin microspheres is characterized by comprising the following steps:
1) Dissolving sericin in deionized water, fully dissolving under magnetic stirring, placing into a centrifuge, centrifuging at a set rotation speed of 8000rpm for 10min, and collecting supernatant to obtain 4wt% sericin water solution;
2) Dissolving 0.48-1.92gF127 in 30mL of absolute ethyl alcohol, controlling the water bath temperature to be 40 ℃, and completely dissolving under magnetic stirring;
3) Taking 3mL of the sericin aqueous solution obtained in the step 1), controlling the water bath temperature to be 40 ℃, setting the mechanical stirring speed to be 500-1500 rpm, and dropwise adding the sericin aqueous solution into the F127/anhydrous ethanol solution obtained in the step 2); the molecular weight of the sericin is 16000 to 20000; the mass ratio of sericin to F127 is 1;
4) Adding 0.3mL5wt% glutaraldehyde/ethanol solution into the sericin suspension obtained in the step 3), controlling the water bath temperature at 40 ℃, and crosslinking for 15min;
5) Pouring the sericin suspension obtained in the step 4) into a 50mL polytetrafluoroethylene lining, packaging the lining into a reaction kettle, and quickly placing the reaction kettle in an oven at 160 to 180 ℃ for reaction for 2 to 8 hours;
6) Centrifuging the sericin suspension obtained in the step 5) for 20min at 15000rpm, pouring out the upper layer liquid, sequentially washing with deionized water and absolute ethyl alcohol, centrifuging for three times, drying the obtained solid in a vacuum oven at 60 ℃ for 12h, and taking out to obtain the sericin microspheres finally.
2. The method for preparing sericin microspheres according to claim 1, wherein: and collecting the sericin microsphere product by using a high-speed centrifuge, wherein the rotating speed of the centrifuge is 12000rpm, and the centrifugation time is 20min.
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