Preparation process of medical polyurethane hydrogel

Abstract

The invention relates to the technical field of medical materials, in particular to a preparation process of medical polyurethane hydrogel. According to the medical polyurethane hydrogel and the preparation method thereof, sodium selenite is used as a selenium source, barbaloin is subjected to selenylation treatment, the prepared selenylated barbaloin can effectively enhance the antibacterial ability of barbaloin, and furthermore, the selenylated barbaloin is doped into a polyurethane prepolymer, so that the medical polyurethane hydrogel with long-acting antibacterial ability can be prepared; according to the medical polyurethane hydrogel, the serine is grafted on the surface of the carbon nano tube, the obtained serine-carbon nano tube can improve the hydrophilicity of the surface of the carbon nano tube, the serine-carbon nano tube can be uniformly dispersed in the medical polyurethane hydrogel, the electric conductivity and the mechanical property of the medical polyurethane hydrogel are further enhanced, and wound protection and healing are promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of medical materials, and more specifically, it relates to a preparation process of a medical polyurethane hydrogel. Background Art

[0002] Medical polyurethane hydrogels have advantages such as good biocompatibility and no irritation to human tissues, and are widely used in medical fields such as drug controlled release systems, wound dressings, medical bandages, artificial organs, and oral treatment materials. Among them, when used as a wound dressing, although the medical polyurethane hydrogel has advantages such as transparency, convenience for observing the wound, ability to fit the wound surface, absorption of wound exudate, and provision of a moist environment conducive to wound healing, the antibacterial activity of the polyurethane hydrogel material itself is poor. In the application of wound dressings, it is prone to problems such as wound infection due to the growth of microorganisms on the surface or inside of the dressing, affecting the wound healing of the wound surface. Although antibacterial agents such as silver ions, titanium dioxide, or antibacterial drugs can be added to the polyurethane hydrogel in the prior art to improve the antibacterial effect of the polyurethane hydrogel, these antibacterial agents are prone to problems such as aggregation, inability to be evenly dispersed, poor antibacterial stability, or easy generation of drug resistance when added to the polyurethane hydrogel, and cannot provide a long-term, stable, and safe antibacterial effect for the polyurethane hydrogel.

[0003] In addition, although the polyurethane hydrogel has advantages such as softness and elasticity, the mechanical properties of the polyurethane hydrogel used as a wound dressing are relatively weak, and it is prone to deformation or damage when subjected to external forces, affecting the fitting degree and sealing performance of the polyurethane hydrogel used as a dressing, thereby affecting its protective and healing effect on the wound. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a preparation process of a medical polyurethane hydrogel.

[0005] A preparation process of a medical polyurethane hydrogel includes the following steps:

[0006] S1: Preparation of selenized aloin. Using sodium selenite as a selenium source, aloin is subjected to selenization treatment, and after dialysis and freeze-drying, selenized aloin is obtained;

[0007] S2: Preparation of doped polyurethane. Using polyethylene glycol, polycaprolactone, L-lysine diisocyanate, and an organotin catalyst to prepare a polyurethane prepolymer, then carrying out a chain extension reaction on the polyurethane prepolymer. Next, an acetone solution containing selenized aloin is added, and heating and stirring reactions are carried out to obtain doped polyurethane;

[0008] S3: Preparation of serine-carbon nanotubes. After surface modification of carbon nanotubes with γ-(2,3-epoxypropoxy)propyltrimethoxysilane, the modified carbon nanotubes are reacted and grafted with serine, and after washing, suction filtration, vacuum drying and pulverization, serine-carbon nanotubes are obtained;

[0009] S4: Preparation of medical polyurethane hydrogel. The serine-carbon nanotubes and doped polyurethane are stirred and mixed, and then polycaprolactone triol is added and stirred to react to obtain a mixed material, and after the mixed material is solidified and formed, a medical polyurethane hydrogel is obtained.

[0010] Further, step S1: Preparation of selenized aloin, includes the following steps:

[0011] S1.1: Dissolve aloin in a nitric acid solution with a mass fraction of 5%, and the material-liquid ratio is 10 mg / mL to obtain an aloin solution;

[0012] S1.2: Add sodium selenite to the aloin solution, stir evenly at 25-30 °C, and then heat in a water bath at 65-75 °C for 8-10 h to obtain a reaction solution;

[0013] S1.3: Adjust the solution pH of the reaction solution to 5-5.4, dialyze in distilled water with a dialysis bag for 2-4 days, and then freeze-dry to obtain selenized aloin.

[0014] Further, the addition amount of sodium selenite is 20-50% of the mass of aloin in the aloin solution.

[0015] Further, step S2: Preparation of doped polyurethane, specifically includes the following steps:

[0016] S2.1: Under a dry nitrogen atmosphere, add 50-70 parts by weight of polyethylene glycol and 24-35 parts by weight of polycaprolactone to a round-bottom flask, dehydrate and dry at 90-100 °C for 60-90 min, and then add 120-180 parts by weight of L-lysine diisocyanate and 0.05-0.2 parts by weight of an organotin catalyst, and react at 75-85 °C for 40-60 min to obtain a polyurethane prepolymer;

[0017] S2.2: Add 18-30 parts by weight of 1,4-butanediol to the polyurethane prepolymer obtained in step S2.1, carry out a chain extension reaction at 60-65 °C for 40-60 min, and then add 60-110 parts by weight of an acetone solution containing selenized aloin, and stir and react at 50-60 °C for 60-90 min to obtain doped polyurethane.

[0018] Further, the organotin catalyst is dibutyltin dilaurate, stannous octoate or dibutyltin diacetate.

[0019] Further, in the acetone solution containing aloe-emodin selenide, the mass fraction of aloe-emodin selenide is 4-9%.

[0020] Further, step S3: Preparation of serine-carbon nanotubes, specifically including the following steps:

[0021] S3.1: Add serine to a phosphate buffer solution with a concentration of 0.2 mol / L and pH = 7. After stirring evenly, a serine solution with a concentration of 3-5 mg / mL is obtained;

[0022] S3.2: Add γ-(2,3-epoxypropoxy)propyltrimethoxysilane to an ethanol solution with a volume fraction of 90%. After stirring evenly, adjust the pH to 5-5.6, and then oscillate and hydrolyze for 30-50 min to obtain a modified solution;

[0023] S3.3: Add carbon nanotubes to the modified solution. The material-liquid ratio of carbon nanotubes to the modified solution is 10-30 mg / mL. Stir and react at 45-60 °C for 1-2 h. After the reaction is completed, let it stand for 6-12 h. After washing, suction filtration, vacuum drying and pulverization, modified carbon nanotubes are obtained;

[0024] S3.4: Stir and mix the modified carbon nanotubes and the serine solution according to a material-liquid ratio of 10-50 mg / mL, and oscillate and react at 50-60 °C for 18-24 h. After the reaction is completed, after washing, suction filtration, vacuum drying and pulverization, serine-carbon nanotubes are obtained.

[0025] Further, the mass-volume ratio of γ-(2,3-epoxypropoxy)propyltrimethoxysilane to the ethanol solution with a volume fraction of 90% is 2-4%.

[0026] Further, step S4: Preparation of medical polyurethane hydrogel, specifically including the following steps:

[0027] Add serine-carbon nanotubes to doped polyurethane. The addition amount of serine-carbon nanotubes is 1-5% of the weight of doped polyurethane. Stir and mix for 20-40 min, and the stirring speed is 100-200 rpm. Then add polycaprolactone triol and stir and react at 55-60 °C for 40-60 min. The addition amount of polycaprolactone triol is 4-10% of the weight of doped polyurethane to obtain a mixed material. Subsequently, pour the mixed material into a mold and cure and form at 40-50 °C to obtain a medical polyurethane hydrogel.

[0028] A medical polyurethane hydrogel is prepared by the preparation process of the above-mentioned medical polyurethane hydrogel.

[0029] The present invention has the following advantages:

[0030] 1. In the present invention, sodium selenite is used as a selenium source to selenize aloin, introducing selenium atoms into the molecular structure of aloin to form selenized aloin. Through the introduction of selenium, selenized aloin can effectively enhance the antibacterial ability of aloin, play an effective inhibitory role on various pathogens such as Staphylococcus aureus and Escherichia coli, and help to be added to the polyurethane hydrogel as an antibacterial agent to provide long-term and stable antibacterial performance.

[0031] 2. In the process of preparing the doped polyurethane in the present invention, first, polyethylene glycol and polycaprolactone are used to form the soft segment of the polyurethane, and 1,4-butanediol is used as a chain extender to construct the hard segment of the polyurethane with L-lysine diisocyanate to prepare a polyurethane prepolymer. Furthermore, selenized aloin is incorporated into the polyurethane prepolymer, so that the hydroxyl group in selenized aloin reacts with the isocyanate group in the polyurethane prepolymer to form a stable covalent bond, enabling selenized aloin to be uniformly and stably dispersed in the network structure of the polyurethane prepolymer, and thus facilitating the preparation of a medical polyurethane hydrogel with long-term antibacterial ability.

[0032] 3. In the present invention, γ-(2,3-epoxypropoxy)propyltrimethoxysilane is used to modify the surface of carbon nanotubes, making the surface of the carbon nanotubes carry amino active groups, and then ring-opening polymerization of serine is initiated to graft serine onto the surface of the carbon nanotubes. The obtained serine-carbon nanotubes increase the hydrophilicity of the surface of the carbon nanotubes, which is beneficial to the uniform dispersion of serine-carbon nanotubes in the medical polyurethane hydrogel, enhance the mechanical properties of the medical polyurethane hydrogel, and further improve the fitting protection of the medical polyurethane hydrogel when used as a wound dressing. Moreover, the carbon nanotubes in the serine-carbon nanotubes can increase the conductivity of the medical polyurethane hydrogel, promote the enhancement of the electrical signal around the wound, and accelerate the wound repair and healing. Detailed implementation mode

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0034] Example 1

[0035] A preparation process of a medical polyurethane hydrogel specifically includes the following steps:

[0036] S1: Preparation of selenized aloin

[0037] S1.1: Dissolve aloin in a nitric acid solution with a mass fraction of 5%, and the material-liquid ratio is 10 mg / mL to obtain an aloin solution;

[0038] S1.2: Add sodium selenite to the aloin solution. The addition amount of sodium selenite is 30% of the mass of aloin in the aloin solution. After stirring evenly at 30 °C, heat it in a water bath at 75 °C for 10 h to obtain a reaction solution.

[0039] S1.3: Adjust the pH of the reaction solution to 5 with anhydrous sodium carbonate, dialyze it in distilled water with a dialysis bag for 4 days, and then freeze-dry it to obtain selenized aloin.

[0040] S2: Preparation of doped polyurethane

[0041] S2.1: Under a dry nitrogen atmosphere, add 70 parts by weight of polyethylene glycol and 32 parts by weight of polycaprolactone to a round-bottom flask, dehydrate and dry them at 100 °C for 60 min. Then, add 180 parts by weight of L-lysine diisocyanate and 0.16 parts by weight of dibutyltin dilaurate, and react at 80 °C for 60 min to obtain a polyurethane prepolymer.

[0042] S2.2: Add 30 parts by weight of 1,4-butanediol to the above-obtained polyurethane prepolymer, carry out a chain extension reaction at 60 °C for 60 min. Then, add 110 parts by weight of an acetone solution containing selenized aloin, and the mass fraction of selenized aloin in the acetone solution containing selenized aloin is 6%. Stir and react at 60 °C for 60 min to obtain doped polyurethane.

[0043] S3: Preparation of serine-carbon nanotubes

[0044] S3.1: Add serine to a phosphate buffer solution with a concentration of 0.2 mol / L and pH = 7. After stirring evenly, obtain a serine solution with a concentration of 5 mg / mL.

[0045] S3.2: Add γ-(2,3-epoxypropoxy)propyltrimethoxysilane to an ethanol solution with a volume fraction of 90%. The mass-volume ratio of γ-(2,3-epoxypropoxy)propyltrimethoxysilane to the ethanol solution is 3%. After stirring evenly, adjust the pH to 5.6 with glacial acetic acid, and then oscillate and hydrolyze for 50 min to obtain a modified solution.

[0046] S3.3: Add carbon nanotubes to the modified solution. The material-liquid ratio of carbon nanotubes to the modified solution is 10 mg / mL. Stir and react at 60 °C for 1 h. After the reaction is completed, let it stand for 12 h, and after washing, suction filtration, vacuum drying and pulverization, obtain modified carbon nanotubes.

[0047] S3.4: Mix the modified carbon nanotubes and serine solution at a material-liquid ratio of 10 mg / mL by stirring, and react with shaking at 60 °C for 24 h. After the reaction, wash, filter by suction, dry in vacuum and crush to obtain serine-carbon nanotubes;

[0048] S4: Preparation of medical polyurethane hydrogel

[0049] Add serine-carbon nanotubes to the doped polyurethane. The addition amount of serine-carbon nanotubes is 5% of the weight of the doped polyurethane. Stir and mix for 40 min at a stirring speed of 200 rpm. Then add polycaprolactone triol and react with stirring at 60 °C for 60 min. The addition amount of polycaprolactone triol is 8% of the weight of the doped polyurethane to obtain a mixed material. Subsequently, pour the mixed material into a mold and cure and form at 50 °C to obtain a medical polyurethane hydrogel. The conductivity of this medical polyurethane hydrogel is 0.073 S / m.

[0050] Example 2

[0051] A preparation process of a medical polyurethane hydrogel specifically includes the following steps:

[0052] S1: Preparation of selenoaloin

[0053] S1.1: Dissolve aloin in a nitric acid solution with a mass fraction of 5%, and the material-liquid ratio is 10 mg / mL to obtain an aloin solution;

[0054] S1.2: Add sodium selenite to the aloin solution. The addition amount of sodium selenite is 30% of the mass of aloin in the aloin solution. After stirring evenly at 25 °C, heat in a water bath at 70 °C for 8 h to obtain a reaction solution;

[0055] S1.3: Adjust the solution pH of the reaction solution to 5.4 with anhydrous sodium carbonate, dialyze in distilled water with a dialysis bag for 4 days, and then freeze-dry to obtain selenoaloin;

[0056] S2: Preparation of doped polyurethane

[0057] S2.1: Under a dry nitrogen atmosphere, add 70 parts by weight of polyethylene glycol and 32 parts by weight of polycaprolactone to a round-bottom flask, dehydrate and dry at 90 °C for 90 min. Then add 180 parts by weight of L-lysine diisocyanate and 0.16 parts by weight of dibutyltin dilaurate, and react at 85 °C for 40 min to obtain a polyurethane prepolymer;

[0058] S2.2: Add 30 parts by weight of 1,4-butanediol to the above-obtained polyurethane prepolymer, carry out a chain extension reaction at 65 °C for 40 min. Then, add 110 parts by weight of an acetone solution containing aloin selenide, and the mass fraction of aloin selenide in the acetone solution containing aloin selenide is 6%. Stir and react at 50 °C for 90 min to obtain doped polyurethane;

[0059] S3: Preparation of serine-carbon nanotubes,

[0060] S3.1: Add serine to a phosphate buffer solution with a concentration of 0.2 mol / L and pH = 7. After stirring evenly, a serine solution with a concentration of 5 mg / mL is obtained;

[0061] S3.2: Add γ-(2,3-epoxypropoxy)propyltrimethoxysilane to an ethanol solution with a volume fraction of 90%. The mass-volume ratio of γ-(2,3-epoxypropoxy)propyltrimethoxysilane to the ethanol solution is 3%. After stirring evenly, adjust the pH to 5 with glacial acetic acid, and then oscillate and hydrolyze for 30 min to obtain a modified solution;

[0062] S3.3: Add carbon nanotubes to the modified solution. The material-liquid ratio of carbon nanotubes to the modified solution is 10 mg / mL. Stir and react at 45 °C for 2 h. After the reaction ends, let it stand for 12 h, and after washing, suction filtration, vacuum drying and pulverization, modified carbon nanotubes are obtained;

[0063] S3.4: Stir and mix the modified carbon nanotubes and the serine solution according to a material-liquid ratio of 10 mg / mL, and oscillate and react at 50 °C for 24 h. After the reaction ends, after washing, suction filtration, vacuum drying and pulverization, serine-carbon nanotubes are obtained;

[0064] S4: Preparation of medical polyurethane hydrogel,

[0065] Add serine-carbon nanotubes to the doped polyurethane. The addition amount of serine-carbon nanotubes is 5% of the weight of the doped polyurethane. Stir and mix for 20 min, and the stirring speed is 200 rpm. Then add polycaprolactone triol, and stir and react at 55 °C for 40 min. The addition amount of polycaprolactone triol is 8% of the weight of the doped polyurethane to obtain a mixed material. Subsequently, pour the mixed material into a mold, and after curing and forming at 40 °C, a medical polyurethane hydrogel is obtained. The conductivity of this medical polyurethane hydrogel is 0.066 S / m.

[0066] Example 3

[0067] A preparation process of a medical polyurethane hydrogel specifically includes the following steps:

[0068] S1: Preparation of aloin selenide,

[0069] S1.1: Dissolve aloin in a nitric acid solution with a mass fraction of 5%, and the solid-liquid ratio is 10 mg / mL to obtain an aloin solution;

[0070] S1.2: Add sodium selenite to the aloin solution. The addition amount of sodium selenite is 50% of the mass of aloin in the aloin solution. After stirring evenly at 30 °C, heat it in a water bath at 75 °C for 10 h to obtain a reaction solution;

[0071] S1.3: Adjust the pH of the reaction solution to 5 with anhydrous sodium carbonate, dialyze it in distilled water with a dialysis bag for 4 days, and then freeze-dry it to obtain selenized aloin;

[0072] S2: Preparation of doped polyurethane

[0073] S2.1: Under a dry nitrogen atmosphere, add 50 parts by weight of polyethylene glycol and 27 parts by weight of polycaprolactone to a round-bottom flask, dehydrate and dry at 100 °C for 60 min, then add 150 parts by weight of L-lysine diisocyanate and 0.09 parts by weight of dibutyltin dilaurate, and react at 80 °C for 60 min to obtain a polyurethane prepolymer;

[0074] S2.2: Add 24 parts by weight of 1,4-butanediol to the obtained polyurethane prepolymer, carry out a chain extension reaction at 60 °C for 60 min, then add 80 parts by weight of an acetone solution containing selenized aloin. The mass fraction of selenized aloin in the acetone solution containing selenized aloin is 9%, and stir and react at 60 °C for 60 min to obtain doped polyurethane;

[0075] S3: Preparation of serine-carbon nanotubes

[0076] S3.1: Add serine to a phosphate buffer solution with a concentration of 0.2 mol / L and pH = 7. After stirring evenly, obtain a serine solution with a concentration of 3 mg / mL;

[0077] S3.2: Add γ-(2,3-epoxypropoxy)propyltrimethoxysilane to an ethanol solution with a volume fraction of 90%. The mass-volume ratio of γ-(2,3-epoxypropoxy)propyltrimethoxysilane to the ethanol solution is 4%. After stirring evenly, adjust the pH to 5.6 with glacial acetic acid, and then oscillate and hydrolyze for 50 min to obtain a modified solution;

[0078] S3.3: Add carbon nanotubes to the modified solution. The solid-liquid ratio of carbon nanotubes to the modified solution is 30 mg / mL. Stir and react at 60 °C for 1 h. After the reaction is completed, let it stand for 12 h, and after washing, suction filtration, vacuum drying and pulverization, obtain modified carbon nanotubes;

[0079] S3.4: Mix the modified carbon nanotubes with the serine solution at a material-liquid ratio of 10 mg / mL by stirring, and carry out an oscillating reaction at 60 °C for 24 h. After the reaction, wash, filter by suction, dry under vacuum and pulverize to obtain serine-carbon nanotubes;

[0080] S4: Preparation of medical polyurethane hydrogel

[0081] Add the serine-carbon nanotubes to the doped polyurethane. The addition amount of the serine-carbon nanotubes is 1% of the weight of the doped polyurethane. Stir and mix for 40 min at a stirring speed of 200 rpm, then add polycaprolactone triol, and carry out a stirring reaction at 60 °C for 60 min. The addition amount of polycaprolactone triol is 6% of the weight of the doped polyurethane to obtain a mixed material. Subsequently, pour the mixed material into a mold, and after curing and forming at 50 °C, a medical polyurethane hydrogel is obtained. The conductivity of this medical polyurethane hydrogel is 0.071 S / m.

[0082] Comparative Example 1

[0083] Compared with Example 1, the difference in Comparative Example 1 is that step S1 is removed, and the acetone solution containing aloeresin A in step S2.2 is replaced with an acetone solution containing aloin, wherein the mass fraction of aloin in the acetone solution containing aloin is 6%, and the remaining steps remain unchanged to prepare a medical polyurethane hydrogel, denoted as Comparative Example 1.

[0084] Comparative Example 2

[0085] Compared with Example 1, the difference in Comparative Example 2 is that step S2.2 is removed, 30 parts by weight of 1,4-butanediol is added to the polyurethane prepolymer obtained in step S2.1, and a chain extension reaction is carried out at 60 °C for 60 min to obtain a polyurethane solution. The doped polyurethane in step S4 is replaced with the polyurethane solution, and the remaining steps remain unchanged to prepare a medical polyurethane hydrogel, denoted as Comparative Example 2.

[0086] After sterilizing the medical polyurethane hydrogels of Examples 1-3 and Comparative Examples 1-2 with an ultraviolet lamp for 5 min, place them on medical gauze placed in a petri dish respectively as hydrogel samples. Dilute Staphylococcus aureus with phosphate buffer saline at pH = 7.4 to a concentration of 1×10 5For the Staphylococcus aureus bacterial solution with a concentration of CFU / mL, 10 μL of the Staphylococcus aureus bacterial solution was evenly smeared on the surface of each hydrogel sample. Then, each hydrogel sample was placed in an incubator at a constant temperature and humidity of 37 °C for 24 h. After the incubation, each hydrogel sample was taken out and placed into a centrifuge tube containing 2 mL of phosphate buffered saline, and shaken with a mixer to completely detach the bacteria on the surface of each hydrogel sample into the phosphate buffered saline in the centrifuge tube. The phosphate buffered saline containing bacteria was serially diluted and then plated. After culturing for 24 h, the viable bacteria count on the surface of each hydrogel sample was calculated by the plate counting method, and taking the viable bacteria count on the surface of the blank control hydrogel as the reference standard, the antibacterial rate after 24 h was calculated.

[0087] The formula for calculating the antibacterial rate is:

[0088] where C 0 is the viable bacteria count of the blank control hydrogel, and C 1 is the viable bacteria count of the hydrogel sample.

[0089] Repeat the above operation steps. The only difference is that the incubation time of each hydrogel sample is adjusted to 72 h, and the antibacterial rate after 72 h is calculated. Based on the antibacterial rate results after 24 h and 72 h, the antibacterial retention rate is calculated. The results are shown in Table 1.

[0090] The formula for calculating the antibacterial retention rate is:

[0091] Table 1:

[0092] Group Bacteriostatic retention rate (%) Example 1 98.13％ Example 2 97.67％ Example 3 98.04％ Comparative Example 1 83.75％ Comparative Example 2 60.48％

[0093] As can be seen from Table 1, for the medical polyurethane hydrogels of Examples 1 - 3 of the present invention, after acting for 72 h, their antibacterial retention rates can all be maintained at a level above 97%, indicating that by adding aloesin selenide to the medical polyurethane hydrogel, it can play a long - term antibacterial role against Staphylococcus aureus and provide more long - term antibacterial performance for the medical polyurethane hydrogel.

[0094] Comparative Example 3

[0095] Compared with Example 1, the difference in Comparative Example 3 is that the serine - carbon nanotubes in step S4 are replaced with carbon nanotubes, and the remaining steps remain unchanged to prepare a medical polyurethane hydrogel, denoted as Comparative Example 3. The conductivity of this medical polyurethane hydrogel is 0.082 S / m.

[0096] Comparative Example 4

[0097] Compared with Example 1, the difference in Comparative Example 4 is that the step of adding and mixing serine-carbon nanotubes in step S4 is removed, and the remaining steps remain unchanged. A medical polyurethane hydrogel is prepared, denoted as Comparative Example 4, and the conductivity of this medical polyurethane hydrogel is 0.027 S / m.

[0098] Grouped according to Examples 1-3 and Comparative Examples 3-4, 3 test samples are selected from the medical polyurethane hydrogels of each group. The tensile strength test is carried out in accordance with GB / T1040.2-2006. The 3 test samples of each group are tested using a CMT4304 universal testing machine, and the tensile speed is 100 mm / min. The average value of each group of test samples is taken as the result, and the results are shown in Table 2.

[0099] Table 2:

[0100] Group Tensile strength (MPa) Example 1 6.26±0.73 Example 2 5.85±0.36 Example 3 6.03±0.48 Comparative Example 3 4.57±0.51 Comparative Example 4 3.16±0.49

[0101] As can be seen from Table 2, for the medical polyurethane hydrogels of Examples 1-3 of the present invention, their tensile strengths are all above 5.8 MPa, and the tensile strength is significantly better than that of the medical polyurethane hydrogels of Comparative Examples 3-4. This shows that adding serine-carbon nanotubes to the medical polyurethane hydrogel can effectively improve the mechanical properties of the medical polyurethane hydrogel. Moreover, compared with Comparative Example 3 where carbon nanotubes are directly added, the improvement effect of the mechanical properties of the medical polyurethane hydrogel by serine-carbon nanotubes in Examples 1-3 is more significant.

[0102] Six mice, all 5 weeks old and with a body weight in the range of 18-20 g, are selected. After 7 days of adaptive feeding, a 1-cm wound is made on the back of each mouse, and the medical polyurethane hydrogels of Examples 1-3 and Comparative Examples 3-4 are used to dress and treat 5 of the mice respectively. The dressing is changed every other day. The remaining 1 mouse is used as a blank group without any treatment. The number of days required for the wounds on the backs of each mouse to completely heal is recorded, and the results are shown in Table 3.

[0103] Table 3:

[0104] Group Healing time (days) Example 1 6 Example 2 9 Example 3 7 Comparative Example 3 11 Comparative Example 4 16 Blank group 21

[0105] As can be seen from Table 3, when using the medical polyurethane hydrogels of Examples 1-3 of the present invention as dressings to treat wounds, the wounds on the backs of the mice can completely heal within 9 days, achieving the effect of accelerating wound repair and healing. This shows that by adding serine-carbon nanotubes, under the synergistic effect of serine and carbon nanotubes, the ability of the medical polyurethane hydrogel to repair and heal wounds can be effectively improved.

[0106] It should be understood that those of ordinary skill in the art can make improvements or transformations based on the above description, and all such improvements and transformations shall fall within the protection scope of the appended claims of the present invention. The parts not described in detail in this specification belong to the prior art well-known to those of ordinary skill in the art.

Claims

1. A preparation process of medical polyurethane hydrogel, characterized in that: The following steps are involved: S1: Preparation of selenized aloin, using sodium selenite as a selenium source to selenize aloin, and then dialyzing and freeze-drying to obtain selenized aloin; S2: Preparation of doped polyurethane, using polyethylene glycol, polycaprolactone, L-lysine diisocyanate and an organic tin catalyst to prepare a polyurethane prepolymer, then subjecting the polyurethane prepolymer to a chain extension reaction, and then adding an acetone solution containing selenized aloin, heating and stirring the reaction to obtain a doped polyurethane; S3: Preparation of serine-carbon nanotubes, using γ-(2,3-epoxypropoxy)propyltrimethoxysilane to modify the surface of carbon nanotubes, and then reacting and grafting the modified carbon nanotubes with serine, washing, filtering, vacuum drying and crushing to obtain serine-carbon nanotubes; S4: Preparation of medical polyurethane hydrogel, stirring and mixing serine-carbon nanotubes and doped polyurethane, then adding polycaprolactone triol, stirring and reacting to obtain a mixture, and curing and molding the mixture to obtain a medical polyurethane hydrogel.

2. The preparation process of a medical polyurethane hydrogel according to claim 1, characterized in that: Step S1: Preparation of selenized aloin, specifically comprising the following steps: S1.1: dissolving aloin in a nitric acid solution having a mass fraction of 5% at a solid-liquid ratio of 10 mg / mL to obtain an aloin solution; S1.2: Add sodium selenite to the aloin solution, stir evenly at 25-30°C, and heat in a water bath at 65-75°C for 8-10 hours to obtain a reaction solution; S1.3: The pH of the reaction solution is adjusted to 5-5.4, and dialyzed in distilled water for 2-4 days using a dialysis bag, followed by freeze-drying to obtain selenized aloin.

3. The preparation process of a medical polyurethane hydrogel according to claim 2, characterized in that: The addition amount of sodium selenite is 20-50% of the mass of aloin in the aloin solution.

4. The preparation process of a medical polyurethane hydrogel according to claim 1, characterized in that: Step S2: Preparation of doped polyurethane, specifically comprising the following steps: S2.1: In a dry nitrogen atmosphere, 50 to 70 parts by weight of polyethylene glycol and 24 to 35 parts by weight of polycaprolactone are added to a round-bottom flask, and dehydrated and dried at 90 to 100° C. for 60 to 90 min, and then 120 to 180 parts by weight of L-lysine diisocyanate and 0.05 to 0.2 parts by weight of an organic tin catalyst are added, and the mixture is reacted at 75 to 85° C. for 40 to 60 min to obtain a polyurethane prepolymer; S2.2: Add 18 to 30 parts by weight of 1,4-butanediol to the polyurethane prepolymer obtained in step S2.1, and carry out a chain extension reaction at 60 to 65° C. for 40 to 60 minutes. Then, add 60 to 110 parts by weight of an acetone solution containing selenized aloin, and stir the reaction at 50 to 60° C. for 60 to 90 minutes to obtain a doped polyurethane.

5. The preparation process of a medical polyurethane hydrogel according to claim 4, characterized in that: The organic tin catalyst is dibutyltin dilaurate, stannous octoate or dibutyltin diacetate.

6. The preparation process of a medical polyurethane hydrogel according to claim 4, characterized in that: In the acetone solution containing selenized aloin, the mass fraction of selenized aloin is 4-9%.

7. The preparation process of a medical polyurethane hydrogel according to claim 1, characterized in that: Step S3: Preparation of serine-carbon nanotubes, specifically comprising the following steps: S3.1: Add serine to a phosphate buffer solution with a concentration of 0.2 mol / L and a pH of 7, and stir evenly to obtain a serine solution with a concentration of 3 to 5 mg / mL; S3.2: adding γ-(2,3-epoxypropoxy)propyltrimethoxysilane to a 90% by volume ethanol solution, stirring evenly, adjusting the pH to 5 to 5.6, and then oscillating and hydrolyzing for 30 to 50 minutes to obtain a modified solution; S3.3: adding carbon nanotubes to the modified solution, the solid-liquid ratio of carbon nanotubes to the modified solution being 10 to 30 mg / mL, stirring the reaction at 45 to 60° C. for 1 to 2 hours, and after the reaction is completed, standing for 6 to 12 hours, washing, filtering, vacuum drying and crushing to obtain modified carbon nanotubes; S3.4: The modified carbon nanotubes and serine solution are stirred and mixed at a solid-liquid ratio of 10 to 50 mg / mL, and oscillated at 50 to 60°C for 18 to 24 hours. After the reaction, the serine-carbon nanotubes are obtained by washing, filtering, vacuum drying and crushing.

8. The preparation process of a medical polyurethane hydrogel according to claim 7, characterized in that: The mass volume ratio of γ-(2,3-epoxypropoxy)propyltrimethoxysilane to the ethanol solution with a volume fraction of 90% is 2-4%.

9. The preparation process of a medical polyurethane hydrogel according to claim 1, characterized in that: Step S4: Preparation of medical polyurethane hydrogel, specifically comprising the following steps: Serine-carbon nanotubes are added to doped polyurethane, wherein the amount of serine-carbon nanotubes added is 1-5% of the weight of the doped polyurethane, and the mixture is stirred for 20-40 minutes at a stirring speed of 100-200 rpm. Polycaprolactone triol is then added, and the mixture is stirred and reacted at 55-60° C. for 40-60 minutes, wherein the amount of polycaprolactone triol added is 4-10% of the weight of the doped polyurethane, to obtain a mixture. Subsequently, the mixture is poured into a mold, and after curing and molding at 40-50° C., a medical polyurethane hydrogel is obtained.

10. A medical polyurethane hydrogel, characterized in that: The medical polyurethane hydrogel is prepared by the preparation process of any one of claims 1 to 9.