Method for preparing water-insoluble fibroin nanometer microcrystal powder

Abstract

The invention discloses a method for preparing water-insoluble fibroin nanometer microcrystal powder. The preparation method comprises the steps of dispersing water-insoluble fibroin powder with average grain diameter smaller than or equal to 3mum into 40-85%wt aqueous sulfuric acid solution, mechanically stirring at temperature of 40-80 DEG C for 0.5-6 hours, carrying out neutralization, dialysis and centrifugation with no more than 20wt% NaOH solution, and then freezing and drying, thus obtaining the water-insoluble fibroin nanometer microcrystal powder. The method is simple and convenient to operate, abundant for raw material sources and low in price, the prepared water-insoluble fibroin nanometer microcrystal powder has high crystallinity and good reinforcing and toughening effects aswell as biocompatibility and biodegradability. The water-insoluble fibroin nanometer microcrystal powder can be used for preparing organic medical nanometer composite materials, and has wide application prospects in the fields of daily cleaning and skin-care and cosmetics and the like.

Description

technical field [0001] The invention relates to a method for preparing water-insoluble silk fibroin nano-microcrystalline powder. Belonging to the field of natural polymer materials, this water-insoluble silk fibroin nano-microcrystalline powder can be widely used in biomedical materials, chemical industry and other industries. Background technique [0002] Natural polymers have a variety of functional groups, which can be modified into new materials through chemical and physical methods, and various functional materials can also be prepared through emerging science and technology. Therefore, it has become one of the most active research fields in materials science today. With the development of nanotechnology, natural polymer nanomaterials, such as nanofibers, nanofilms, nanoparticles, and nanospheres, have emerged. Natural polymer nanomaterials can be widely used in the fields of biological functional materials, such as immobilization of enzymes, separation and extractio...

AI Technical Summary

Problems solved by technology

The shortcoming of this method is: what adopted is water-soluble silk fibroin, and its molecular weight is not big, so in the silk fibroin solution and the organic solvent mixing process, the yield of silk fibroin dissolution is very low, and the organic solvent consumption is very large, there is difficulty lack of industrialization

The disadvantage of this method is: due to the high activity of the enzyme degradation reaction, after mixing with the silk fibroin solution, the enzymatic cleavage reaction occurs rapidly, and it is difficult to control the degree of enzymatic cleavage, resulting in difficult control of the particle size of the obtained silk fibroin nanoparticles; in addition, the silk fibroin dissolution process Complicated, the solvent used is a high-concentration salt solution. During the dialysis process, the high-concentration salt ions are difficult to dialyze completely, and the residual ions can cause the enzyme to lose activity and make it difficult for the enzymatic hydrolysis reaction to proceed normally.

In addition, the common disadvantage of the above-mentioned methods is that silk fibroin needs to be dissolved and then regenerated to prepare silk fibroin nanoparticles. During the dissolving process of silk fibroin, the β-sheet structure of silk fibroin crystallization region is destroyed, and it appears as random coils in aqueous solution. structure, therefore, in the process of mixing silk fibroin solution with organic solvents, or when directly freeze-drying, the dissolved silk fibroin is mainly in a random coil structure with low crystallinity

Therefore, although the obtained nanoparticles have a nanometer scale, it is difficult to form the structure of natural silk fibroin itself, thus partially losing the original excellent properties of silk fibroin, such as the regenerated silk fibroin nanopowder with random coil structure. When biomedical materials are applied or used as drug carriers, the biodegradation rate in the body is too fast to achieve the expected effect

Therefore, adopt the above-mentioned method to exist complex preparation process, cause the pollution of organic solvent more serious, seriously destroy the secondary structure of silk fibroin in the preparation process and thus affect its original good performance, and be difficult to industrialization etc.

Therefore, it is urgent to find a better preparation method. It is theoretically and practically feasible to prepare nanoparticles by direct acid hydrolysis of natural polymers without dissolution. It has been successfully applied to polysaccharide natural polymer whiskers ( Such as the preparation of cellulose whiskers, starch whiskers, and chitin whiskers), but the application in the preparation of water-insoluble silk fibroin nanoparticles has not been reported.

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