Temperature-responsive chitosan solution and method for preparing the same

Abstract

The application discloses a temperature-responsive chitosan solution and a preparation method thereof, which is composed of hydroxybutyl chitosan, acid, salt, water and the like. The preparation method comprises the following steps: firstly, preparing the hydroxybutyl chitosan in a heterogeneous phase; secondly, adding the salt; and finally, adding the acid solution and dissolving at low temperature to obtain the temperature-responsive chitosan solution. The chitosan solution is in a solution state at low temperature, and can form a micellar emulsion when the temperature rises. The light transmittance of the micellar emulsion can be adjusted by changing the concentration of the hydroxybutyl chitosan, the concentration of the salt and the concentration of the acid. The chitosan solution prepared by the method has a wide application prospect in the fields of tissue engineering, drug delivery system, cell culture and cosmetics.

Description

Technical Field

[0001] This invention belongs to the field of materials technology and relates to a temperature-responsive chitosan solution and its preparation method. Background Technology

[0002] Chitosan is the only alkaline polysaccharide among natural polysaccharides, and it is widely used in food additives, textiles, agriculture, environmental protection, beauty and health care, cosmetics, antibacterial agents, medical fibers, medical dressings, artificial tissue materials, drug sustained-release materials, gene transduction vectors, biomedical fields, medical absorbable materials, tissue engineering carrier materials, medical and drug development, and many other fields and daily chemical industries. Hydroxybutyl chitosan is a derivative of chitosan, exhibiting water solubility and temperature responsiveness. Currently, hydroxybutyl chitosan is mainly prepared by two methods: heterogeneous and homogeneous phases. Heterogeneous hydroxybutyl chitosan aqueous solutions can achieve reversible transformation between solution and gel with temperature changes, while homogeneous hydroxybutyl chitosan aqueous solutions can achieve reversible transformation between solution and micelles with temperature changes. The water solubility, biocompatibility, and temperature sensitivity of hydroxybutyl chitosan make it play an important role in tissue engineering, postoperative adhesion prevention, drug delivery, and the pharmaceutical field.

[0003] Currently, heterogeneously prepared hydroxybutyl chitosan has been industrialized, and related medical device products already exist in China (e.g., Beijing Medical Device Registration Certificate 20202140315, Thermosensitive Hydroxybutyl Chitosan Wound Dressing). However, heterogeneously prepared hydroxybutyl chitosan aqueous solutions can only achieve the conversion between solution and gel, while homogeneously prepared hydroxybutyl chitosan requires higher concentrations of alkali and urea, longer reaction times, and generates more waste, making it unsuitable for industrialization and subject to numerous limitations in practical applications. Summary of the Invention

[0004] The purpose of this invention is to provide a temperature-responsive chitosan solution and its preparation method. This solution allows for reversible transformation of the solution and micelles at different temperatures. The transmittance of the micelle emulsion can be adjusted by changing the concentrations of hydroxybutyl chitosan, salt, and acid. The chitosan aqueous solution prepared by this method has broad application prospects in sensors, tissue engineering, drug delivery systems, cell culture, and cosmetics.

[0005] According to the first aspect of the present invention, the present invention adopts the following technical solution:

[0006] A temperature-responsive chitosan solution is characterized by being composed of hydroxybutyl chitosan, salt, acid, and water. This solution allows for reversible transformation of the solution and micelles at different temperatures; the light transmittance of the micelle emulsion can be adjusted by changing the concentrations of hydroxybutyl chitosan, salt, and acid.

[0007] According to another aspect of the purpose of the present invention, the present invention adopts the following technical solution:

[0008] A method for preparing a temperature-responsive chitosan solution as described above, using chitosan as raw material, synthesizing hydroxybutyl chitosan by introducing hydroxybutyl groups, dissolving it in an acidic aqueous solution, and then adding salt to obtain a temperature-responsive chitosan solution, the specific steps of which are as follows: (1) preparing hydroxybutyl chitosan HBC; (2) adding inorganic salt; (3) adding hydrochloric acid solution, dissolving at low temperature to obtain a temperature-responsive chitosan solution.

[0009] In step (2), the inorganic salt is one or more of sodium chloride, potassium chloride, lithium chloride, sodium acetate, potassium acetate, lithium acetate, etc.

[0010] Furthermore, the acidic aqueous solution in step (3) is one or more of hydrochloric acid, acetic acid, sulfuric acid, phosphoric acid, etc.

[0011] The key problem solved by this invention is how to develop a temperature-responsive chitosan solution with easily adjustable solution and micellar transformation, based on commercially available heterogeneously prepared hydroxybutyl chitosan. Adding salts, acids, or other ions to the heterogeneously prepared hydroxybutyl chitosan aqueous solution can break the hydrogen bonds between chitosan and water molecules, altering its solubility in water and causing the originally extended chitosan molecular chains to contract into clusters. Therefore, this hydroxybutyl chitosan aqueous solution can exhibit solution and micellar transformation characteristics at different temperatures. The hydroxybutyl chitosan aqueous solution of this invention is a transparent solution at low temperatures, and forms a micellar emulsion when the temperature rises. The temperature-responsive chitosan solution prepared by this method has broad application prospects in tissue engineering, drug delivery systems, cell culture, and cosmetics.

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0013] Figure 1 These are photos of the temperature response test of chitosan solution HBC-4.

[0014] Figure 2 This is a photograph of the results of the Tyndall effect experiment on chitosan solution HBC-4. Detailed Implementation

[0015] To further understand the present invention, the following detailed description of a temperature-responsive chitosan solution provided by the present invention is provided in conjunction with embodiments. However, the present invention is not limited to these embodiments. Non-essential improvements and adjustments made by those skilled in the art under the core guiding principles of the present invention are still within the protection scope of the present invention.

[0016] (I) Preparation of temperature-responsive chitosan solutions

[0017] Example 1: Heterogeneous preparation of hydroxybutyl chitosan (HBC)

[0018] (1) Weigh 20g of chitosan, dissolve it in 1000ml of 1% HCl aqueous solution, filter, add 1mol / L NaOH solution to the filtrate to obtain a precipitate, wash with distilled water until neutral, desalt with 70% ethanol, dehydrate with 95% ethanol, and dry at 50℃ to obtain a purified chitosan sample.

[0019] (2) Disperse 3g of purified chitosan in 30ml of 50% NaOH aqueous solution, stir for 24h, filter, squeeze out excess alkali solution, and obtain solid. Add the obtained solid to 60ml of isopropanol aqueous solution (V 异丙醇 V 水 = 10 : 10), stir well, heat to 60℃, add 80 ml of 1,2-epoxybutane dropwise, and react for 24 h. Cool to room temperature, and adjust the pH of the system to neutral by adding 10% HCl aqueous solution dropwise. Filter off the insoluble matter, add 3 times the volume of ethanol to precipitate, centrifuge, dry the precipitate, and obtain hydroxybutyl chitosan (HBC).

[0020] The preparation of hydroxybutyl chitosan (HBC) can also refer to the preparation method disclosed in Chinese Patent 201110214776.X.

[0021] Example 2, Preparation of chitosan solution HBC-1

[0022] Accurately weigh 10 mg of HBC prepared in Example 1, add 1 g of sodium chloride, add 0.1 M hydrochloric acid to a final volume of 5 g, and dissolve at low temperature to obtain chitosan solution HBC-1.

[0023] Example 3, Preparation of chitosan solution HBC-2

[0024] Accurately weigh 25 mg of HBC prepared in Example 1, add 1 g of sodium chloride, add 0.1 M hydrochloric acid to 5 g, and dissolve at low temperature to obtain chitosan solution HBC-2.

[0025] Example 4, Preparation of chitosan solution HBC-3

[0026] Accurately weigh 50 mg of HBC prepared in Example 1, add 1 g of sodium chloride, add 0.1 M hydrochloric acid to 5 g, and dissolve at low temperature to obtain chitosan solution HBC-3.

[0027] Example 5: Preparation of chitosan solution HBC-4

[0028] Accurately weigh 50 mg of HBC prepared in Example 1, add 1 g of sodium chloride, add 0.01 M hydrochloric acid to 5 g, and dissolve at low temperature to obtain chitosan solution HBC-4.

[0029] Example 6, Preparation of chitosan solution HBC-5

[0030] Accurately weigh 50 mg of HBC prepared in Example 1, add 0.75 g of sodium chloride, add 0.1 M hydrochloric acid to 5 g, and dissolve at low temperature to obtain chitosan solution HBC-5.

[0031] (II) Temperature Response Test

[0032] Experimental procedure: Add a comparative example. Place the samples prepared in Examples 2-6 and Comparative Examples 1-3 in water baths at 4℃ and 45℃ respectively for at least 10 minutes and observe the state of the examples and comparative examples.

[0033] Comparative Example 1: Preparation of chitosan solution HBC-5

[0034] Accurately weigh 50 mg of HBC prepared in Example 1, add 1 g of sodium chloride, add purified water to 5 g, and dissolve at low temperature to obtain Comparative Example-1.

[0035] Comparative Example 2: Preparation of chitosan solution HBC-5

[0036] Accurately weigh 50 mg of HBC prepared in Example 1, add 0.1 M hydrochloric acid to a final volume of 5 g, and dissolve at low temperature to obtain Comparative Example-2.

[0037] Comparative Example 3: Preparation of chitosan solution HBC-5

[0038] Accurately weigh 1g of sodium chloride, add 1M hydrochloric acid to make 5g, and dissolve at low temperature to obtain Comparative Example-3.

[0039] Conclusion: The results are shown in Table 1. HBC-1, HBC-2, HBC-3, HBC-4, and HBC-5 consistently formed colorless solutions at low temperatures and emulsions at high temperatures, indicating that the chitosan solutions prepared by this method have good temperature responsiveness. Comparative Example 1 failed to completely dissolve or disperse at different temperatures, indicating that hydrochloric acid solution facilitates the dissolution of hydroxybutyl chitosan in the presence of high concentrations of sodium chloride. Comparative Example 2 remained a colorless solution at different temperatures, indicating that the hydrochloric acid solution of hydroxybutyl chitosan did not exhibit a significant temperature response. Comparative Example 3 remained a colorless solution at different temperatures, suggesting that hydroxybutyl chitosan is key to the solution's temperature responsiveness.

[0040] The chitosan solution HBC-4 was in the following states at 4℃ and 45℃: Figure 1 , 2As shown, the chitosan solution HBC-4 was significantly clearer at 45℃ than at 4℃. Figure 1 ), and there is a clear Tyndall effect ( Figure 2 ).

[0041]

[0042] Remark: [a] Unless otherwise specified, all balances refer to hydrochloric acid content, with a concentration of 0.1M. [b] The remainder is hydrochloric acid with a concentration of 0.01M; [c] The remainder is purified water.

[0043] (III) Transmittance Test

[0044] Experimental procedure: Examples 2-6 were placed in water baths at 4℃ and 45℃ respectively for at least 10 minutes, and the transmittance of each solution at 800nm ​​was measured using a UV spectrophotometer.

[0045] Conclusion: The results are shown in Table 2. The degree of conversion between solution and colloidal emulsion is related to the concentration of HBC, salt concentration, and hydrochloric acid concentration.

[0046]

[0047] Remark: [a] The remainder is hydrochloric acid with a concentration of 0.1M; [b] The remainder is hydrochloric acid with a concentration of 0.01M.

Claims

1. A method for preparing a temperature-responsive chitosan solution, characterized by, The temperature-responsive chitosan solution is composed of hydroxybutyl chitosan, salt, acid and water; the preparation method includes the following steps: (1) preparing hydroxybutyl chitosan HBC in a heterogeneous manner; (2) adding inorganic salt to hydroxybutyl chitosan HBC; (3) adding hydrochloric acid solution, dissolving at low temperature to prepare a temperature-responsive chitosan solution.

2. The method of claim 1 wherein In step (2), the inorganic salt is one or more of sodium chloride, potassium chloride, lithium chloride, sodium acetate, potassium acetate, and lithium acetate.

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