CN105839294A - Method for preparing nanocrystalline cellulose-fibroin film by electrostatic spinning method - Google Patents

Abstract

The invention relates to a method for preparing nano-microcrystalline cellulose-silk fibroin film through an electrospinning method. The present invention prepares NCC-silk fibroin film by adding appropriate self-made NCC in the silk fibroin solution, and prepares NCC-silk fibroin film by electrospinning after fully mixing, studies the mechanical property change of silk fibroin film before and after adding NCC; Prepared NCC-silk fibroin The film was soaked in methanol to study the change of mechanical properties of silk fibroin film. The electrostatic spinning membrane of the invention is safe and non-toxic, has simple process and low production cost, and can improve the mechanical properties and surface properties of the silk fibroin membrane.

Description

A method for preparing nano-microcrystalline cellulose-silk fibroin film by electrospinning

technical field

The invention belongs to the technical field of light industry, and in particular relates to a method for preparing nano-microcrystalline cellulose-silk fibroin film through an electrostatic spinning method.

Background technique

Electrospinning is an effective method for high-speed preparation of nanofibers [Dong Xiaoying, Dong Xin. Preparation technology and application of electrospinning nanofibers [J]. Synthetic Fiber Industry, 2009,32

(4):48-51.], silk fibroin has good mechanical properties, controlled biodegradability and biocompatibility[Zhang X H, Baughman C B, Kaplan D L. In vitro evaluation of electrospun silk fibroin scaffolds for vascular cell growth[J].

Biomaterials 2008; 29(14): 2217-2227.], silk fibroin superfine fibers can be prepared by electrospinning. However, the electrospun fiber membranes usually prepared by the electrospinning method are relatively brittle and have low mechanical properties, so their application range is limited.

Nanocrystalline cellulose (NCC), as a renewable and degradable new nanomaterial, can be prepared by degrading natural cellulose or microcrystalline cellulose. Due to the relationship between raw materials, NCC not only has the characteristics of nanoparticles, but also maintains the basic chemical structure of cellulose, and optimizes the performance of cellulose. It has a large specific surface area, super adsorption capacity, good mechanical properties, and ultra-fine structure. , high crystallinity, high Young's modulus and strong chemical reactivity, etc. [M. Paakko, M. Ankerfors, H. Kosonen. Enzymatic hydrolysis combined with mechanical shearing and high-pressure homogenization for nanoscale cellulose fibrils and strong gels[J]. Biomacromolecules, 2007, 8(6): 1934-1941] advantage. It is the focus of researchers to replace NCC with other materials or directly apply it in different fields to optimize certain properties of materials or generate new properties.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention provides a preparation method of nano-microcrystalline cellulose electrospun membrane, comprising the following steps:

Step (1): Boil mulberry silk in Na ₂ CO ₃ aqueous solution (0.05%w/w) for 30 minutes, repeat this operation three times to remove sericin in silk and obtain silk fibroin; prepare CaCl ₂ : C ₂ H ₅ OH: H ₂ O = 1:2:8 (molar ratio) ternary mixed solvent, put silk fibroin in it, set the bath ratio to 1:50, and place it at a temperature of 75±1°C for preparation The silk fibroin solution is produced, and after the solution is dialyzed and filtered through a dialysis bag, the regenerated silk fibroin with many holes and spongy shape is formed by freeze-drying.

Step (2): Set the mass fraction of the electrospinning liquid to 8%, and add a certain amount of NCC. Put the calculated regenerated silk fibroin and NCC into a sample bottle, dissolve in hexafluoroisopropanol, stir and mix well, then pour the NCC-spinning solution into the injection syringe and fix it , the spinning distance between the needle tip and the collecting plate is 12cm, the spinning voltage is 15kv, the spinning flow rate is 0.6ml/h, and electrospinning is carried out, and the finally prepared NCC-silk fibroin film is placed in a vacuum desiccator Reserved.

Step (3): Prepare 90% methanol aqueous solution, place the prepared NCC-silk fibroin film in it for 10 minutes, take it out and dry it at room temperature.

In the above method, the Na ₂ CO ₃ described in step (1) belongs to salts, and the sodium carbonate containing ten crystal waters is a colorless crystal, and the crystal water is unstable and easily weathered, turning into white powder Na ₂ CO ₃ , It is a strong electrolyte, has the compatibility and thermal stability of salt, is easily soluble in water, and its aqueous solution is alkaline.

In the above method, the CaCl ₂ described in step (1) is colorless cubic crystal, white or off-white, granular, honeycomb block, spherical, irregular granular, or powder. Odorless, slightly bitter taste, cheap and easy to get.

In the above method, the C ₂ H ₅ OH described in step (1) is a flammable, volatile, colorless and transparent liquid at normal temperature and pressure, and its aqueous solution has the smell of wine and is slightly irritating. . It has the smell of wine and a stimulating spicy taste, slightly sweet.

In the above method, the methanol described in step (3) is a colorless, volatile liquid with an alcohol smell.

In the present invention, firstly, mulberry silk is placed in a Na ₂ CO ₃ solution, and sericin in the silk is removed to obtain silk fibroin. Secondly, silk fibroin is placed in a ternary mixed solvent, and NCC is added to combine NCC and silk fibroin. Finally, the silk fibroin was electrostatically spun into a film, which improved the mechanical properties and surface properties of the silk film to a certain extent.

detailed description

The present invention prepares NCC-silk fibroin film by adding appropriate self-made NCC in silk fibroin solution, and prepares NCC-silk fibroin film by electrospinning method after fully mixing, and studies the mechanical property change of silk fibroin film before and after adding NCC; Prepared NCC-silk fibroin The film was soaked in methanol to study the change of mechanical properties of silk fibroin film.

Nanocrystalline cellulose can be used as a good reinforcing filler due to its good strength and rigidity. At the same time, compared with inorganic fillers, it is naturally renewable, non-polluting, and biocompatible. In addition, because there are a large number of active hydroxyl groups on its surface, it is easy to modify. These advantages are incomparable to inorganic fillers. Therefore, the present invention improves the mechanical properties of the silk film by adding nano-microcrystalline cellulose.

The present invention will be further described below in conjunction with the examples, but the protection scope of the present invention is not limited to the scope expressed by the examples. Parts and percentages in the examples are by dry weight unless otherwise stated.

Example 1

Boil mulberry silk in Na ₂ CO ₃ aqueous solution (0.05%w/w) for 30 minutes, repeat this operation three times to remove sericin in silk and obtain silk fibroin; prepare CaCl ₂ : C ₂ H ₅ OH : H ₂ O =1:2:8 (molar ratio) of the ternary solvent, silk fibroin is placed therein, the bath ratio is set to 1:50, placed at a temperature of 75±1°C to prepare a silk fibroin solution, the After the solution is dialyzed and filtered through a dialysis bag, the regenerated silk fibroin with many holes and spongy shape is produced by freeze-drying. Set the mass fraction of the spinning solution to 8%, and the added nanocrystalline cellulose to 1%. Put the weighed and calculated silk fibroin and NCC into a 20ml sample bottle, dissolve in hexafluoroisopropanol (HFIP), stir and mix well, then pour the NCC-spinning solution into the syringe , fixed, the spinning distance between the needle tip and the collecting plate is 12cm, the spinning voltage is 15kv, and the spinning flow rate is 0.6ml/h, electrospinning is carried out, and the NCC-silk fibroin film finally prepared is placed in vacuum drying Store in container for later use. Prepare 90% methanol aqueous solution, place the prepared NCC-silk fibroin film in it for 10 minutes, take it out and dry it at room temperature. After treatment, the tensile strength increased from 3.6MPa to 9.0MPa, an increase of 5.4MPa, and the tensile strength increased by 111%. The average thickness of silk fibroin film before methanol treatment was 0.1068mm, and the average thickness of silk fibroin film after treatment was 0.0447mm. Compared with the silk fibroin membrane without NCC before and after methanol treatment, the toughness of the composite silk fibroin membrane was greatly improved.

Example 2

Put mulberry silk in Na ₂ CO ₃ aqueous solution (0.05%w/w, mass percentage concentration) and boil for 30min, repeat this operation three times to remove sericin in silk to obtain silk fibroin; prepare CaCl ₂ : C ₂ H ₅ OH: H ₂ O =1:2:8 (molar ratio) ternary solvent, put silk fibroin in it, set the bath ratio to 1:50, and place it at a temperature of 75±1°C to prepare silk After the solution is dialyzed and filtered through a dialysis bag, the regenerated silk fibroin with many holes and spongy shape is formed by freeze-drying. Set the mass fraction of the spinning solution to 8%, and the added nanocrystalline cellulose to 3%. Put the weighed and calculated silk fibroin and NCC into a 20ml sample bottle, dissolve in HFIP, stir and mix well, then pour the NCC-spinning solution into the injection syringe, fix it, and collect the needle tip and The spinning distance between the plates was 12cm, the spinning voltage was 15kv, and the spinning flow rate was 0.6ml/h. Electrospinning was carried out, and the finally prepared NCC-silk fibroin film was placed in a vacuum desiccator for standby. Prepare 90% methanol aqueous solution, place the prepared NCC-silk fibroin film in it for 10 minutes, take it out and dry it at room temperature. Before and after treatment, the tensile strength of 3% NCC-silk fibroin film increased from 1.8MPa to 9.8MPa, an increase of 8.0MPa, and the tensile strength increased by 444%. The average thickness of untreated silk fibroin film was 0.1370mm, and the average thickness of silk fibroin film after treatment was 0.0328mm.

Example 3

Boil mulberry silk in Na ₂ CO ₃ aqueous solution (0.05%w/w) for 30 minutes, repeat this operation three times to remove sericin in silk and obtain silk fibroin; prepare CaCl ₂ : C ₂ H ₅ OH : H ₂ O =1:2:8 (molar ratio) of the ternary solvent, silk fibroin is placed therein, the bath ratio is set to 1:50, placed at a temperature of 75±1°C to prepare a silk fibroin solution, the After the solution is dialyzed and filtered through a dialysis bag, the regenerated silk fibroin with many holes and spongy shape is produced by freeze-drying. Set the mass fraction of the spinning solution to 8%, and the added nanocrystalline cellulose to 5%. Put the weighed and calculated silk fibroin and NCC into a 20ml sample bottle, dissolve in HFIP, stir and mix well, then pour the NCC-spinning solution into the injection syringe, fix it, and collect the needle tip and The spinning distance between the plates was 12cm, the spinning voltage was 15kv, and the spinning flow rate was 0.6ml/h. Electrospinning was carried out, and the finally prepared NCC-silk fibroin film was placed in a vacuum desiccator for standby. Prepare 90% methanol aqueous solution, place the prepared NCC-silk fibroin film in it for 10 minutes, take it out and dry it at room temperature. After treatment, the tensile strength of 5% NCC-silk fibroin film increased from 2.2MPa to 6.6MPa, an increase of 4.4MPa, and the tensile strength increased by 220%. The average thickness of the untreated silk fibroin film was 0.0838mm, and the average thickness of the silk fibroin film after treatment was 0.0500mm.

The performance-improving material of the electrospun membrane adopted in the present invention is NCC. As a renewable and degradable new nanomaterial, NCC can be prepared by degrading natural cellulose or microcrystalline cellulose. The nano-microcrystalline cellulose electrospun membrane prepared by the present invention reduces the random coil and α-helical conformation of silk fibroin due to the treatment with methanol, making the structure more stable; having more β-parallel structures, making the structure more stable. It is more stable and makes silk fibroin insoluble in water, so it has good mechanical properties and surface properties.

Claims (1)

1. the method preparing nano micro crystal cellulose-fibroin membrane by method of electrostatic spinning, it is characterised in that comprise the steps:

Step (1): mulberry silk is placed in Na₂CO₃Aqueous solution boils, continues 30 minutes, repeat this operation three times, for removing the sericin in silkworm silk, obtain fibroin；Preparation CaCl₂: C₂H₅OH: H₂O The ternary mixed solvent of=1:2:8, this ratio is mol ratio, fibroin is placed in ternary mixed solvent, arranging bath raio is 1:50, it is placed at a temperature of 75 ± 1 DEG C and prepares silk fibroin solution, by this solution after bag filter dialysis, filtering, the spongiform regenerated silk fibroin of freeze-dried mechanism emptying aperture much；

Step (2): the mass fraction arranging spinning liquid is 8%, adds nano micro crystal cellulose；The fibroin albumen that weighing is calculated and nano micro crystal cellulose, it is placed in sample bottle, it is dissolved in hexafluoroisopropanol, after agitated son is sufficiently mixed uniformly, nano micro crystal cellulose-spinning liquid is poured in syringe cylinder, fix, between needle point and collecting board, spinning distance is 12cm, and spinning voltage is 15kv, and spinning flow rate is 0.6ml/h, carrying out electrostatic spinning, the nano micro crystal cellulose-fibroin membrane finally prepared is placed in stand for standby use in vacuum desiccator；

Step (3): prepare 90% methanol aqueous solution, be placed in one process 10min by the nano micro crystal cellulose-fibroin membrane prepared, and takes out and is dried at room temperature for.