A transparent biomass polyvinyl alcohol hydrogel and its preparation method and application

Abstract

The invention discloses a transparent biomass polyvinyl alcohol hydrogel and its preparation method and application, preparation method includes mixing biomass polyvinyl alcohol with water to obtain polyvinyl alcohol aqueous solution, freeze-thaw cycle obtains transparent biomass polyvinyl alcohol hydrogel;Number of freeze-thaw cycles 1 3 times, each freezing and thawing time 2 8h, when PVA used for every milliliter of water is 150mg, freeze-thaw 1 time, freezing and thawing time is 2 8h, or freeze-thaw 3 times, each freezing and thawing time is 2h;When PVA used for every milliliter of water is 100mg, freeze-thaw 1 time, freezing and thawing time is 2 8h, or freeze-thaw 3 times, each freezing and thawing time is 2 4h;When PVA used for every milliliter of water is 50mg, freeze-thaw 1 time, freezing and thawing time is 4 8h, or freeze-thaw 3 times, each freezing and thawing time is 2 8h. The hydrogel transparency of the present invention is high, and it is convenient to observe wound healing.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a transparent biomass polyvinyl alcohol (PVA) hydrogel and a preparation method and application thereof. Background Art

[0002] Hydrogel wound dressings can significantly accelerate the tissue repair process by promoting wound autolysis and debridement, maintaining a moist healing environment, and relieving pain (especially without wound adhesion during replacement). At the same time, their self-adhesion, plasticity, and excellent tissue adhesion effectively avoid the problems of traditional dressings that easily cause wound drying, mechanical damage, and poor patient comfort.

[0003] Polyvinyl alcohol (hereinafter referred to as PVA) has excellent biocompatibility and degradability, and can form hydrogels without the addition of additional chemical cross-linking agents (glutaraldehyde, etc.). It is one of the most common materials for making wound dressings. However, the current large-scale production and application of PVA (hereinafter referred to as fossil PVA) is mainly based on petrochemical processes such as the calcium carbide acetylene method, the natural gas acetylene method or the petroleum ethylene method. Its production process is not only accompanied by the emission of a large amount of pollutants (such as particulate matter, SO2, CO2, tar residue, etc.), exacerbating environmental health risks, but also faces the problem of rising costs due to the non-renewable raw materials. Biomass-derived PVA (hereinafter referred to as biomass PVA) is derived from biomass resources such as sugarcane and potatoes, which can achieve secondary utilization of resources and effectively reduce environmental pollution. In terms of application, fossil PVA hydrogel has the defect of insufficient transparency when used alone as a wound dressing, and often requires the introduction of additives such as dimethyl sulfoxide or inorganic salts to regulate the optical properties. For example, the Chinese patent application document with publication number CN112646206 A discloses a highly transparent polyvinyl alcohol hydrogel and its preparation method and application. It uses polyvinyl alcohol and inorganic salts as raw materials and water as solvent, wherein the concentration of polyvinyl alcohol is 3-30wt% and the concentration of inorganic salts is 0.5-29.9wt%. The prepared polyvinyl alcohol hydrogel has high transparency and can be used in medicine, materials, sensors and other fields. However, it requires the addition of inorganic salts for modification, which not only makes the preparation method cumbersome, but more importantly, it will complicate the composition of the hydrogel and may increase the potential toxicity risk. Summary of the Invention

[0004] The technical problem to be solved by the present invention is how to prepare a transparent polyvinyl alcohol hydrogel with simple ingredients.

[0005] The present invention solves the above technical problems through the following technical means:

[0006] A method for preparing a transparent biomass polyvinyl alcohol hydrogel comprises the following steps:

[0007] S1. Evenly mixing biomass polyvinyl alcohol with water to obtain a polyvinyl alcohol aqueous solution; wherein the mass of the polyvinyl alcohol used per milliliter of water is 50-150 mg;

[0008] S2. Subjecting the polyvinyl alcohol aqueous solution obtained in S1 to a freeze-thaw cycle to obtain the transparent biomass polyvinyl alcohol hydrogel; wherein the number of freeze-thaw cycles is 1-3 times, and the freezing and thawing time for each time is 2-8 hours, and when the mass of polyvinyl alcohol used per milliliter of water is 50 mg, the number of freeze-thaw cycles is 1 time, and the freezing and thawing time is 4-8 hours, or the number of freeze-thaw cycles is 3 times, and the freezing and thawing time for each time is 2-8 hours; when the mass of polyvinyl alcohol used per milliliter of water is 100 mg, the number of freeze-thaw cycles is 1 time, and the freezing and thawing time is 2-8 hours, or the number of freeze-thaw cycles is 3 times, and the freezing and thawing time for each time is 2-4 hours; when the mass of polyvinyl alcohol used per milliliter of water is 150 mg, the number of freeze-thaw cycles is 1 time, and the freezing and thawing time is 2-8 hours, or the number of freeze-thaw cycles is 3 times, and the freezing and thawing time for each time is 2 hours.

[0009] Preferably, in S1, the biomass polyvinyl alcohol is produced using one or more biomass resources of sugarcane and potatoes as raw materials.

[0010] Preferably, in S1, the biomass polyvinyl alcohol is prepared from molasses from one or more of sugarcane and potatoes, then alcohol is prepared from the molasses, ethylene is prepared from the alcohol, vinyl acetate is prepared from ethylene, polyvinyl acetate is prepared from vinyl acetate, and finally polyvinyl acetate is prepared from polyvinyl acetate.

[0011] Preferably, in S1, the degree of polymerization of the biomass polyvinyl alcohol is 2600 and the degree of alcoholysis is 99%.

[0012] Preferably, in S1, the biomass polyvinyl alcohol is biomass polyvinyl alcohol model 2699 provided by Anhui Wanwei Group Co., Ltd.

[0013] Preferably, the mass of polyvinyl alcohol used per milliliter of water is 50 mg, the number of freeze-thaw cycles is 1, and the freezing and thawing time is 4-8 h, or the number of freeze-thaw cycles is 3, and the freezing and thawing time is 2-8 h each time; or, the mass of polyvinyl alcohol used per milliliter of water is 100 mg, the number of freeze-thaw cycles is 1, and the freezing and thawing time is 2-8 h, or the number of freeze-thaw cycles is 3, and the freezing and thawing time is 2-4 h each time; or, the mass of polyvinyl alcohol used per milliliter of water is 150 mg, the number of freeze-thaw cycles is 1, and the freezing and thawing time is 2-8 h, or the number of freeze-thaw cycles is 3, and the freezing and thawing time is 2 h each time.

[0014] Preferably, in S1, the mass of polyvinyl alcohol used per milliliter of water is 50 mg; and / or the number of freeze-thaw cycles is 3 times, and the freezing and thawing time each time is 2-8 hours.

[0015] Preferably, the mass of polyvinyl alcohol used per milliliter of water is 50 mg, and the freeze-thaw cycle is repeated three times, with each freezing and thawing time being 8 hours.

[0016] Preferably, S1 specifically includes the following steps: mixing biomass polyvinyl alcohol with water, stirring at room temperature, then continuing to stir while heating until the biomass polyvinyl alcohol is completely dissolved, and then standing at room temperature to eliminate bubbles, to obtain the polyvinyl alcohol aqueous solution.

[0017] Preferably, the stirring time at room temperature is 30 min; the temperature is raised while stirring until the temperature reaches 85° C., and then stirring is continued.

[0018] Preferably, the freezing temperature is -20°C and the thawing temperature is room temperature.

[0019] The present invention also provides a transparent biomass polyvinyl alcohol hydrogel, which is prepared by adopting the preparation method of the transparent biomass polyvinyl alcohol hydrogel.

[0020] Preferably, the transparency of the transparent biomass polyvinyl alcohol hydrogel is 91.38%-100%.

[0021] The present invention also proposes an application of the transparent biomass polyvinyl alcohol hydrogel as a wound dressing.

[0022] The above-mentioned dressing is used to load various types of drugs such as analgesics, anti-inflammatory drugs, and healing-promoting drugs, and is used to treat wounds, ulcer wounds, bacterial infection wounds and refractory wounds.

[0023] Preferably, the wound dressing is used to load one or more of ibuprofen, gentamicin sulfate and sulfa metronidazole.

[0024] Preferably, the transparent biomass polyvinyl alcohol hydrogel is loaded with drugs by physical immersion.

[0025] In comparison, biomass PVA, made from renewable resources like sugarcane and potatoes, significantly reduces environmental pollution while realizing high-value utilization of agricultural byproducts, demonstrating sustainable development potential. The present invention discovered that hydrogel dressings made from biomass PVA, without the addition of other chemical reagents, exhibit high transparency and can monitor wound changes at any time, demonstrating broad application prospects in the biomedical field.

[0026] The advantages of the present invention are:

[0027] (1) The present invention provides a highly transparent biomass-derived polyvinyl alcohol hydrogel that can be used as a wound dressing. The hydrogel is simple to prepare and does not require the addition of an additional cross-linking agent, which can reduce costs. Compared with traditional fossil-derived PVA hydrogels, the hydrogel has the advantages of high transparency, high adhesion, and high drug loading rate. It is suitable for the physical loading and sustained release of various drugs such as ibuprofen, gentamicin sulfate, and sulfa metronidazole, thereby having multiple effects of relieving wound pain, anti-inflammatory, antibacterial, and promoting healing.

[0028] (2) Biomass-derived PVA comes from biomass resources such as sugarcane and potatoes, which can achieve secondary utilization of resources and effectively reduce environmental pollution.

[0029] (3) The hydrogel of the present invention is water-absorbent and can promote fluid absorption by the wound surface, preventing adhesion. The soft hydrogel increases patient comfort. Its high transparency facilitates observation of wound healing. The hydrogel has an appropriate adhesion strength and is not easy to fall off or remove. The high drug loading rate can improve drug utilization efficiency and reduce resource waste.

[0030] (4) The hydrogel of the present invention is formed by the freeze-thaw method, without the need for additional chemical reagents to assist in cross-linking. The dressing is loaded with drugs by physical immersion. The resulting hydrogel dressing has good biocompatibility and no toxic chemical residues. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Comparison of the residual organic impurities in fossil and biomass PVA particles in Example 1 of the present invention;

[0032] Figure 2 The effects of fossil and biomass PVA on the viability of human epidermal keratinocytes in Example 1 of the present invention;

[0033] Figure 3 Comparison of light transmittance of biomass and fossil PVA hydrogels at 700 nm in Examples 3-10 of the present invention;

[0034] Figure 4 Comparison of light transmittance of biomass and fossil PVA hydrogels at 700 nm in Examples 11-19 of the present invention;

[0035] Figure 5 Comparison of light transmittance of biomass and fossil PVA hydrogels at 700 nm in Examples 20-28 of the present invention;

[0036] Figure 6 This is a comparison of the transparency of biomass and fossil PVA hydrogels in Example 7 of the present invention;

[0037] Figure 7This is a scanning electron micrograph of the fossil PVA hydrogel in Example 7 of the present invention;

[0038] Figure 8 This is a scanning electron micrograph of the biomass PVA hydrogel in Example 7 of the present invention;

[0039] Figure 9 The effect of the fossil and biomass PVA hydrogel extracts on the viability of human epidermal keratinocytes in Example 7 of the present invention;

[0040] Figure 10 The amount of inflammatory factor TNF-α released after the fossil and biomass PVA hydrogel extracts in Example 7 of the present invention acted on mouse mononuclear macrophages for 24 hours;

[0041] Figure 11 The amount of inflammatory factor IL-6 released after the fossil and biomass PVA hydrogel extracts in Example 7 of the present invention acted on mouse mononuclear macrophages for 24 hours;

[0042] Figure 12 The amount of inflammatory factor IL-1β released after the fossil and biomass PVA hydrogel extracts in Example 7 of the present invention acted on mouse mononuclear macrophages for 24 hours;

[0043] Figure 13 Comparison of the adhesion between fossil and biomass PVA hydrogels and pigskin in Example 7 of the present invention;

[0044] Figure 14 This is a physical diagram showing the adhesion between the biomass PVA hydrogel and pigskin in Example 7 of the present invention;

[0045] Figure 15 This is a physical diagram showing the adhesion between the biomass PVA hydrogel and a centrifuge tube filled with approximately 45 mL of water in Example 7 of the present invention;

[0046] Figure 16 Comparison of drug loading (ibuprofen) of fossil and biomass PVA hydrogels in Example 34 of the present invention;

[0047] Figure 17 The sustained release effect of the drug (ibuprofen) from the fossil and biomass PVA hydrogel in Example 34 of the present invention;

[0048] Figure 18 Comparison of drug loading (gentamicin sulfate) of fossil and biomass PVA hydrogels in Example 35 of the present invention;

[0049] Figure 19 The sustained release effect of the drug (gentamicin sulfate) from the fossil and biomass PVA hydrogel in Example 35 of the present invention;

[0050] Figure 20 Comparison of drug loading (sulfa-metronidazole) of fossil and biomass PVA hydrogels in Example 36 of the present invention;

[0051] Figure 21 This is the sustained release effect of the drug (sulfa metronidazole) of the fossil and biomass PVA hydrogel in Example 36 of the present invention. DETAILED DESCRIPTION

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0053] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0054] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the field or according to the product instructions.

[0055] The following biomass-derived and fossil-derived PVAs were provided by Anhui Wanwei Group Co., Ltd. Both PVA grades are 2699, indicating a degree of polymerization of 2600 and a degree of alcoholysis of 99%. Reagents such as ibuprofen, gentamicin sulfate, and sulfa-metronidazole were purchased from Sigma-Aldrich.

[0056] Example 1

[0057] Determination of metal and organic impurities and biocompatibility assessment of PVA from fossil and biomass sources (i.e. fossil PVA and biomass PVA)

[0058] (1) Determination of metal and organic impurity residues in PVA

[0059] Inductively coupled plasma mass spectrometry was used to quantitatively analyze the residual amounts of metal impurities (aluminum, calcium, chromium, copper, iron, and zinc) in fossil PVA and biomass PVA particles. The results are shown in Table 1. Table 1 shows that the metal impurities (aluminum, calcium, chromium, copper, and zinc) in biomass PVA are less than those in fossil PVA. Gas chromatography was used to detect the residual amounts of organic impurities (methanol, acetic acid, methyl acetate, and paraldehyde) in the two PVA particles. Figure 1 and Table 2, Figure 1 Table 2 shows that the residual amounts of organic matter (acetic acid, methyl acetate, and methanol) in biomass PVA are lower than those in fossil PVA.

[0060] Table 1

[0061]

[0062] Table 2

[0063]

[0064] (2) Preparation of PVA aqueous solution

[0065] 5g of biomass PVA was added to 100mL of ultrapure water and stirred at room temperature for 30 minutes. The mixture was then heated to 85°C and stirred until the PVA particles were completely dissolved. The mixture was then allowed to stand at room temperature to expel air bubbles. This produced a biomass PVA aqueous solution. A similar method was used to prepare a fossil PVA aqueous solution using fossil PVA instead of biomass PVA.

[0066] (3) Biocompatibility evaluation of PVA

[0067] The fossil and biomass PVA aqueous solutions in step (2) were diluted to 0.5, 1, 1.5, 2, and 2.5 mg / mL using DMEM medium containing 10% volume fraction of fetal bovine serum, and then added to the cell culture dish to treat the human epidermal keratinocytes after attachment. DMEM medium containing 10% volume fraction of fetal bovine serum without PVA was used as a control. CCK8 detection was performed after 24 hours. The results are as follows: Figure 2 , Figure 2 The results showed that both PVAs were non-toxic to human epidermal keratinocytes within the concentration range of 0-2.5 mg / mL.

[0068] Example 2

[0069] Preparation of fossil and biomass PVA hydrogels

[0070] The biomass and fossil PVA aqueous solutions were frozen and thawed once in a -20°C refrigerator for 2 h. The specific steps are as follows:

[0071] (1) Preparation of PVA aqueous solution

[0072] The method is the same as step (2) in Example 1.

[0073] (2) Preparation of PVA hydrogel

[0074] Pour the biomass PVA aqueous solution in step (1) into a mold, freeze it in a -20°C refrigerator for 2 hours, and thaw it at room temperature for 2 hours to prepare a PVA hydrogel for later use. Use the same method to prepare fossil PVA hydrogel.

[0075] Examples 3-10

[0076] The preparation of fossil and biomass PVA hydrogels differs from Example 2 only in the number of freeze-thaw cycles and the time for each freeze and thaw. The number of freeze-thaw cycles and the time for each freeze and thaw cycle for each example are shown in Table 3.

[0077] Table 3

[0078]

[0079] The gelation conditions of Examples 2-10 are shown in Table 4, where × indicates that gelation cannot be achieved, and √ indicates that gelation can be achieved. As shown in Table 4, Example 2 cannot produce a hydrogel, while Examples 3-10 can all produce a hydrogel.

[0080] Table 4

[0081]

[0082] Example 11

[0083] The preparation of fossil and biomass PVA hydrogels differed from that of Example 2 only in that the amount of PVA was changed to 10 g to prepare the PVA aqueous solution.

[0084] Examples 12-19

[0085] The preparation of fossil and biomass PVA hydrogels differed from Example 11 only in that different freeze-thaw cycles and freezing and thawing times were used. The freeze-thaw cycles and freezing and thawing times for each example are shown in Table 5 below.

[0086] Table 5

[0087]

[0088] The gelation conditions of Examples 11-19 are shown in Table 6, where × indicates that gelation cannot be formed and √ indicates that gelation can be formed. As shown in Table 6, hydrogels can be prepared in Examples 11-19.

[0089] Table 6

[0090]

[0091] Example 20

[0092] The preparation of fossil and biomass PVA hydrogels was different from that in Example 2 only in that the amount of PVA was changed to 15 g to prepare the PVA aqueous solution.

[0093] Examples 21-28

[0094] The preparation of fossil and biomass PVA hydrogels differed from Example 20 only in the number of freeze-thaw cycles and the time for each freeze and thaw cycle. The number of freeze-thaw cycles and the time for each freeze and thaw cycle for each example are shown in Table 7 below.

[0095] Table 7

[0096]

[0097] The gelation conditions of Examples 20-28 are shown in Table 8, where × indicates that gelation cannot be formed and √ indicates that gelation can be formed. As shown in Table 8, Examples 20-28 can all prepare hydrogels.

[0098] Table 8

[0099]

[0100] Example 29

[0101] Transparency testing of PVA hydrogel

[0102] The fossil and biomass PVA hydrogels in Examples 3-28 were cut into rectangles with a thickness of 1 mm. The absorbance of all hydrogels at a wavelength of 700 nm was measured using a UV-visible spectrophotometer to calculate the transmittance of the hydrogels. The results are as follows: Figure 3-5 shown.

[0103] Figure 3 Comparison of the transmittance of fossil and biomass PVA hydrogels in Examples 3-10, where 2h, 4h, and 8h represent the freezing / thawing time in each example. From left to right, each two bar graphs form a group, with a total of 8 groups, representing Examples 3-10 in sequence; Figure 3 This shows that among the hydrogels prepared under the same freeze-thaw conditions, the transmittance of biomass PVA hydrogel is higher than that of fossil PVA hydrogel.

[0104] Figure 4 Comparison of the transmittance of fossil PVA and biomass PVA hydrogels in Examples 11-19, where 2h, 4h, and 8h represent the freezing / thawing time in each example. From left to right, each two bar graphs form a group, with a total of 9 groups, representing Examples 11-19 in sequence; Figure 4 This shows that among the hydrogels prepared under the same freeze-thaw conditions, the transmittance of biomass PVA hydrogel is higher than that of fossil PVA hydrogel.

[0105] Figure 5 Comparison of the transmittance of fossil and biomass PVA hydrogels in Examples 20-28, where 2h, 4h, and 8h represent the freezing / thawing time in each example. From left to right, each two bar graphs form a group, with a total of 9 groups, representing Examples 20-28 in sequence; Figure 5This shows that among the hydrogels prepared under the same freeze-thaw conditions, the transmittance of biomass PVA hydrogel is higher than that of fossil PVA hydrogel.

[0106] Figure 6 This is a photo of the fossil and biomass PVA hydrogel prepared in Example 7 (the PVA aqueous solution was frozen at -20°C for 8 hours, thawed at room temperature for 8 hours, and repeatedly frozen and thawed three times).

[0107] Depend on Figure 3-6 It can be seen that compared with fossil PVA hydrogel, biomass PVA hydrogel has higher transmittance. The transmittance of biomass PVA hydrogel prepared in Examples 3-7, Examples 11-15 and Examples 20-23 reaches 91.38-100%, while the transmittance of fossil PVA hydrogel and biomass PVA hydrogel prepared in other examples is less than 90%.

[0108] Example 30

[0109] Microstructural characterization of fossil and biomass PVA hydrogels

[0110] The fossil and biomass PVA hydrogels in Example 7 were freeze-dried and then photographed using a scanning electron microscope. Figure 7 and Figure 8 , Figure 7 This is a scanning electron microscope image of the fossil PVA hydrogel in Example 7, which shows that there is no obvious pore structure on the surface of the fossil PVA hydrogel. Figure 8 This is a scanning electron microscope image of the biomass PVA hydrogel in Example 7, which shows that the biomass PVA hydrogel is a porous network structure, which is beneficial for drug loading and sustained release.

[0111] Example 31

[0112] Biocompatibility evaluation of PVA hydrogel

[0113] The extract of fossil and biomass PVA hydrogel (prepared by the method in Example 7) (refer to ISO10993-12; GB / T16886.12-2017, i.e., the extraction ratio of hydrogel to DMEM medium containing 10% volume fraction of fetal bovine serum is 1.25 cm 2 / mL, extracted at 37℃ for 24h) to treat attached human epidermal keratinocytes, and DMEM medium containing 10% volume fraction of fetal bovine serum without hydrogel was used as control. CCK8 detection was performed after 24 hours. The results are as follows Figure 9 , Figure 9 It was shown that fossil and biomass PVA hydrogels had no effect on the viability of human epidermal keratinocytes, implying that both PVA hydrogels were non-toxic to cells.

[0114] Example 32

[0115] Immunotoxicity evaluation of PVA hydrogel

[0116] The extract of fossil and biomass PVA hydrogel (prepared by the method in Example 7) (refer to ISO10993-12; GB / T16886.12-2017, i.e., the extraction ratio of hydrogel to DMEM medium containing 10% volume fraction of fetal bovine serum is 1.25 cm 2 / mL, immersion at 37℃ for 24h) were used to treat adherent mouse mononuclear macrophages, and DMEM medium containing 10% fetal bovine serum without hydrogel was used as a control. After 24 hours, the release of inflammatory factors (TNF-α, IL-6 and IL-1β) was detected using ELISA kits. The results are shown in Figure 2. Figure 10-12 , indicating that fossil and biomass PVA hydrogels do not produce inflammatory responses to cells.

[0117] Example 33

[0118] Detection of adhesion between PVA hydrogel and pigskin

[0119] Prepare rectangular fossil and biomass PVA hydrogel samples (prepared by the method of Example 7) and fix them on a glass slide. At the same time, prepare a rectangular piece of pigskin and fix it on another glass slide with glue. Glue the adhesive surface of the hydrogel to the pigskin surface and press with a 100g weight for 5 minutes to ensure a good bonding effect. Place the fixed sample in the upper and lower clamps of a universal material testing machine, set a stable tensile speed of 5 mm / min, and start the testing machine to stretch until the hydrogel sample separates from the pigskin surface. The results are shown in Figure 2. Figure 13 As shown, the adhesion between biomass PVA hydrogel and pig skin is greater than that between fossil PVA hydrogel and pig skin. Figure 14 This is a physical picture of the adhesion between biomass PVA hydrogel and pig skin. Figure 15 This is a physical picture of the adhesion between the biomass PVA hydrogel and the EP tube filled with about 45 mL of water, indicating that the biomass PVA hydrogel has sufficient adhesion and the hydrogel dressing prepared therefrom adheres to the wound area and is not easy to fall off.

[0120] Example 34

[0121] PVA hydrogel drug loading (ibuprofen) and drug release experiments

[0122] (1) PVA hydrogel loaded with drugs (ibuprofen)

[0123] A certain amount of ibuprofen powder was taken and prepared into a 2 mg / mL ibuprofen suspension with ultrapure water. Fossil and biomass PVA hydrogels (prepared by the method in Example 7) were placed in two centrifuge tubes containing 10 mL of the above ibuprofen suspension and soaked for 72 hours for physical loading of the drug.

[0124] (2) PVA hydrogel drug loading detection

[0125] 1) Establish a standard curve for ibuprofen

[0126] Ibuprofen was prepared into a series of suspensions with different concentrations, and the absorbance A of the drug was measured using a UV-visible spectrophotometer. A standard curve of the drug was obtained by plotting the absorbance A against the drug concentration C.

[0127] 2) PVA hydrogel drug loading detection

[0128] The hydrogel loaded with drugs in step (1) was taken out, and the drug concentration of the remaining drug suspension was detected using a UV-visible spectrophotometer. The volume of the remaining drug suspension was also measured, and the drug loading of the hydrogel was calculated using the following formula:

[0129]

[0130] Where L is the drug loading capacity of the hydrogel (mg / g); C0 and C1 are the concentrations of the drug suspension before and after drug loading (mg / mL); V0 and V1 are the volumes of the drug solution before and after drug loading (mL); M is the mass of the hydrogel before drug loading (g). Figure 16 As shown, it shows that biomass PVA hydrogel has a higher drug loading capacity and the drug loading amount is significantly higher than that of fossil PVA hydrogel.

[0131] (3) In vitro drug release experiment

[0132] The hydrogel loaded with ibuprofen in (1) was placed in a centrifuge tube containing 50 mL of 1× phosphate buffered saline (1× PBS) for drug release experiment. The centrifuge tube was placed in a shaker, set at 37°C and 100 rpm. The cumulative release method was used, and samples were taken at set time intervals and fresh PBS was added. The absorbance of the drug was measured using a UV-visible spectrophotometer, and the concentration of the drug was calculated based on the standard curve to obtain the cumulative release of the drug at each time point. The release endpoint was reached when the absorbance of the drug in the release solution could no longer be detected. The experimental results are shown in Figure 2. Figure 17 As shown, both PVAs have a certain sustained-release effect on ibuprofen and can continuously release drugs for up to 6 hours.

[0133] Example 35

[0134] PVA hydrogel drug loading (gentamicin sulfate) and drug release experiments

[0135] (1) Gentamycin sulfate solution was diluted to 3 mg / mL with ultrapure water. Fossil and biomass PVA hydrogels (prepared by the method in Example 7) were placed in two centrifuge tubes containing 10 mL of the above-mentioned gentamicin sulfate solution and soaked for 72 h for physical loading of the drug.

[0136] (2) Drug loading detection

[0137] The method is the same as step (2) in Example 34. The results are as follows Figure 18 , indicating that biomass PVA hydrogel has a high drug loading capacity.

[0138] (3) In vitro drug release experiment

[0139] The method is the same as step (3) in Example 34. The results are as follows Figure 19 , indicating that both PVA hydrogels have a certain sustained-release effect on gentamicin sulfate.

[0140] Example 36

[0141] (1) PVA hydrogel drug loading (sulfa metronidazole) and drug release experiments

[0142] Sulfamyl metronidazole was dispersed in ultrapure water to prepare a 3 mg / mL suspension. Fossil and biomass PVA hydrogels (prepared by the method in Example 7) were placed in two centrifuge tubes containing 10 mL of the above drug suspension and immersed for 72 hours for physical loading of the drug.

[0143] (2) Drug loading detection

[0144] The method is the same as step (2) in Example 34. The results are as follows Figure 20 , indicating that the drug loading capacity of biomass PVA hydrogel is greater than that of fossil PVA hydrogel.

[0145] (3) In vitro drug release experiment

[0146] The method is the same as step (3) in Example 34. The results are as follows Figure 21 , indicating that both PVA hydrogels have a certain sustained-release effect on sulfa metronidazole.

[0147] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a transparent biomass polyvinyl alcohol hydrogel, characterized by: The following steps are involved: S1. Evenly mixing biomass polyvinyl alcohol with water to obtain a polyvinyl alcohol aqueous solution; wherein the biomass polyvinyl alcohol is biomass polyvinyl alcohol model 2699 provided by Anhui Wanwei Group Co., Ltd.; S2. Subjecting the polyvinyl alcohol aqueous solution obtained in S1 to a freeze-thaw cycle to obtain the transparent biomass polyvinyl alcohol hydrogel; when the mass of polyvinyl alcohol used per milliliter of water is 50 mg, the number of freeze-thaw cycles is 1, and the freezing and thawing time is 4-8 h, or the number of freeze-thaw cycles is 3, and each freezing and thawing time is 2-8 h; when the mass of polyvinyl alcohol used per milliliter of water is 100 mg, the number of freeze-thaw cycles is 1, and the freezing and thawing time is 2-8 h, or the number of freeze-thaw cycles is 3, and each freezing and thawing time is 2-4 h; when the mass of polyvinyl alcohol used per milliliter of water is 150 mg, the number of freeze-thaw cycles is 1, and the freezing and thawing time is 2-8 h, or the number of freeze-thaw cycles is 3, and each freezing and thawing time is 2 h.

2. The method for preparing the transparent biomass polyvinyl alcohol hydrogel according to claim 1, characterized in that: In S1, the degree of polymerization of the biomass polyvinyl alcohol is 2600 and the degree of alcoholysis is 99%.

3. The method for preparing the transparent biomass polyvinyl alcohol hydrogel according to claim 1, characterized in that: S1 specifically includes the following steps: mixing biomass polyvinyl alcohol with water, stirring at room temperature, then continuing to stir while heating until the biomass polyvinyl alcohol is completely dissolved, and then standing at room temperature to eliminate bubbles, thereby obtaining the polyvinyl alcohol aqueous solution.

4. The method for preparing a transparent biomass polyvinyl alcohol hydrogel according to any one of claims 1 to 3, characterized in that: The freezing temperature is -20°C, and the thawing temperature is room temperature.

5. A transparent biomass polyvinyl alcohol hydrogel, characterized by: The transparent biomass polyvinyl alcohol hydrogel is prepared by the preparation method of any one of claims 1 to 4.

6. The transparent biomass polyvinyl alcohol hydrogel according to claim 5, characterized in that: Its light transmittance is 91.38-100%.

7. A wound dressing, characterized in that: The transparent biomass polyvinyl alcohol hydrogel is prepared according to claim 5 or 6.

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