Copolymer of fibroin and poly L-lactic acid, preparation method thereof through ring-opening polymerization and application thereof

Abstract

The invention discloses a copolymer of fibroin and poly L-lactic acid, which comprises the following structure. The invention also discloses a preparation method for the copolymer through ring-opening polymerization and application of the copolymer in biomedical materials. The preparation method comprises the following steps of: preparing the copolymer of the fibroin and the poly L-lactic acid by performing the ring-opening polymerization on L-lactide in a molten state and performing copolymerization with the fibroin; and adopting solid phase polymerization to perform post condensation polymerization so as to further improve the molecular weight of the copolymer, reduce the contents of a monomer and a low molecular weight polymer in the system, and prepare a copolymer with narrow molecular weight distribution. A solvent is not used in the polymerization process, so the process is simple and the product cost is low. The preparation method can prepare the copolymers of the fibroin and poly the L-lactic acid with different number-average molecular weights. The copolymer of the fibroin and poly the L-lactic acid prepared by the method can improve the hydrophilic property, the biocompatibility and the cellular affinity of a polylactic acid material, and control the degrading speed of the material.

Description

Technical field:

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a copolymer of silk protein and poly-L-lactic acid, a preparation method and application thereof. Background technique:

[0002] Polylactic acid (PLA) is a biodegradable and absorbable polymer material with good biocompatibility. It has excellent mechanical properties, and its raw material can be prepared by fermentation of starch to realize the regeneration of resources. PLA has been widely used in tissue engineering and other biomedical fields, and its degradation products can participate in the metabolism of the human body with low toxicity. PLA is a hydrophobic polymer with poor adhesion to cells. Pure polylactic acid as a tissue engineering material will cause some mild inflammatory reactions after being implanted into the organism. The brittleness of polylactic acid is high, the mechanical strength is low, and the degradation cycle is difficult to c...

Examples

Embodiment 1

[0059] L-lactide, dehydrated silk protein powder (number-average molecular mass 3000), SnCl 2 / p-toluenesulfonic acid catalyst system (SnCl 2 The molar content accounts for 50% of the whole catalyst system) into the polymerization tank. SnCl 2 The dosage is 0.5wt% of L-lactide, and the mass ratio of L-lactide to silk protein is 4:1. The pressure of the system was gradually reduced to 0 mmHg (manometer reading) and then sealed, the reaction temperature was 170° C., and the reaction time was 10 hours. Then the temperature was lowered to 130° C., and the solid state reaction was carried out for 10 hours. After the polymerization, the obtained copolymer was dissolved in ethyl acetate, filtered and precipitated with ether, and the filtered precipitate was vacuum-dried at 65° C. for 16 hours to obtain a purified copolymer of silk protein and poly-L-lactic acid. After purification, the copolymer is a yellow powder with a molecular weight of 18,000, a yield of 73%, no melting poi...

Embodiment 2

[0061] L-lactide, dehydrated silk protein powder (the number average relative molecular mass is 3000), SnCl 2 / naphthalenesulfonic acid catalyst system (SnCl 2 The molar content accounts for 50% of the whole catalyst system) into the polymerization tank. SnCl 2 The dosage is 0.5wt% of L-lactide, and the mass ratio of L-lactide to silk protein is 6:1. The pressure of the system was gradually reduced to 10 mm Hg and then sealed, the reaction temperature was 170° C., and the reaction time was 10 hours. Then the temperature was lowered to 130° C., and the solid state reaction was carried out for 10 hours. After the polymerization was complete, the resulting copolymer was dissolved in ethyl acetate, filtered and precipitated with diethyl ether. The filtered precipitate was vacuum-dried at 65° C. for 16 hours to obtain a purified polylactic acid and silk fibroin peptide chain copolymer. The purified copolymer is a yellow powder with a molecular weight of 24,000, a yield of 73%,...

Embodiment 3

[0063] Add L-lactide, dehydrated silk protein powder (the number-average molecular mass is 1000), stannous isooctanoate / naphthalenesulfonic acid catalyst system (the molar content of stannous isooctanoate accounts for 50% of the entire catalyst system) in the polymerization kettle. The amount of stannous isooctanoate is 0.5wt% of L-lactide, and the mass ratio of L-lactide to silk protein is 10:1. The pressure of the system was gradually reduced to 2 mm Hg and then sealed, the reaction temperature was 170° C., and the reaction time was 15 hours. Then the temperature was lowered to 140° C., and the solid phase reaction was carried out for 15 hours. After the polymerization was complete, the copolymer was dissolved in ethyl acetate, filtered and precipitated with diethyl ether. The filtered precipitate was vacuum-dried at 65° C. for 10 hours to obtain a purified copolymer of silk protein and poly-L-lactic acid. The purified copolymer is a yellow powder with a molecular weight ...

Technical field:

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a copolymer of silk protein and poly-L-lactic acid, a preparation method and application thereof. Background technique:

[0002] Polylactic acid (PLA) is a biodegradable and absorbable polymer material with good biocompatibility. It has excellent mechanical properties, and its raw material can be prepared by fermentation of starch to realize the regeneration of resources. PLA has been widely used in tissue engineering and other biomedical fields, and its degradation products can participate in the metabolism of the human body with low toxicity. PLA is a hydrophobic polymer with poor adhesion to cells. Pure polylactic acid as a tissue engineering material will cause some mild inflammatory reactions after being implanted into the organism. The brittleness of polylactic acid is high, the mechanical strength is low, and the degradation cycle is difficult to c...

Examples

Embodiment 1

[0059] L-lactide, dehydrated silk protein powder (number-average molecular mass 3000), SnCl 2 / p-toluenesulfonic acid catalyst system (SnCl 2 The molar content accounts for 50% of the whole catalyst system) into the polymerization tank. SnCl 2 The dosage is 0.5wt% of L-lactide, and the mass ratio of L-lactide to silk protein is 4:1. The pressure of the system was gradually reduced to 0 mmHg (manometer reading) and then sealed, the reaction temperature was 170° C., and the reaction time was 10 hours. Then the temperature was lowered to 130° C., and the solid state reaction was carried out for 10 hours. After the polymerization, the obtained copolymer was dissolved in ethyl acetate, filtered and precipitated with ether, and the filtered precipitate was vacuum-dried at 65° C. for 16 hours to obtain a purified copolymer of silk protein and poly-L-lactic acid. After purification, the copolymer is a yellow powder with a molecular weight of 18,000, a yield of 73%, no melting poi...

Embodiment 2

[0061] L-lactide, dehydrated silk protein powder (the number average relative molecular mass is 3000), SnCl 2 / naphthalenesulfonic acid catalyst system (SnCl 2 The molar content accounts for 50% of the whole catalyst system) into the polymerization tank. SnCl 2 The dosage is 0.5wt% of L-lactide, and the mass ratio of L-lactide to silk protein is 6:1. The pressure of the system was gradually reduced to 10 mm Hg and then sealed, the reaction temperature was 170° C., and the reaction time was 10 hours. Then the temperature was lowered to 130° C., and the solid state reaction was carried out for 10 hours. After the polymerization was complete, the resulting copolymer was dissolved in ethyl acetate, filtered and precipitated with diethyl ether. The filtered precipitate was vacuum-dried at 65° C. for 16 hours to obtain a purified polylactic acid and silk fibroin peptide chain copolymer. The purified copolymer is a yellow powder with a molecular weight of 24,000, a yield of 73%,...

Embodiment 3

[0063] Add L-lactide, dehydrated silk protein powder (the number-average molecular mass is 1000), stannous isooctanoate / naphthalenesulfonic acid catalyst system (the molar content of stannous isooctanoate accounts for 50% of the entire catalyst system) in the polymerization kettle. The amount of stannous isooctanoate is 0.5wt% of L-lactide, and the mass ratio of L-lactide to silk protein is 10:1. The pressure of the system was gradually reduced to 2 mm Hg and then sealed, the reaction temperature was 170° C., and the reaction time was 15 hours. Then the temperature was lowered to 140° C., and the solid phase reaction was carried out for 15 hours. After the polymerization was complete, the copolymer was dissolved in ethyl acetate, filtered and precipitated with diethyl ether. The filtered precipitate was vacuum-dried at 65° C. for 10 hours to obtain a purified copolymer of silk protein and poly-L-lactic acid. The purified copolymer is a yellow powder with a molecular weight ...

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