Preparation method and application of pachyman gel microspheres

Abstract

The application provides a preparation method and application of Pachyman gel microspheres, and the preparation method is as follows: Pachyman is dissolved in alkali liquor to obtain a Pachyman solution; isooctane and a first surfactant are mixed and stirred to obtain oil phase I; the Pachyman solution is added dropwise into the oil phase I and stirred to obtain a water-in-oil system; isooctane and a second surfactant are mixed and stirred to obtain oil phase II; the oil phase II is added dropwise into the water-in-oil system and stirred to obtain a mixed solution; acid liquor is added dropwise into the mixed solution and stirred, and then the obtained product is washed with ethanol and deionized water in sequence, and is left to stand and separate into layers to obtain a crude Pachyman gel microsphere product; tert-butyl alcohol is added into the crude Pachyman gel microsphere product and stirred, and then the obtained product is left to stand, freeze-dried and obtained Pachyman gel microspheres. The Pachyman gel microspheres prepared by the method have a normal distribution of particle size and a smooth surface, and can be applied to the medical field as a carrier.

Description

Technical Field

[0001] This invention belongs to the field of Poria cocos polysaccharide processing technology, specifically relating to a method for preparing Poria cocos polysaccharide gel microspheres and their application. Background Technology

[0002] Poria cocos (Schw.) Wolf is the dried sclerotium of the fungus Poria cocos (Schw.) Wolf (family Polyporaceae). Polysaccharides are one of the main chemical components of Poria cocos, accounting for approximately 70-90% of the total weight of the sclerotium. Acidic polysaccharides account for over 80% of the content in Poria cocos, and are water-insoluble. However, in clinical applications, Poria cocos polysaccharides are mostly extracted by decoction, and pharmacological studies have primarily focused on the water-soluble components, with very little research on the alkali-soluble components, resulting in the loss of effective components. Therefore, further research into the functional properties of water-insoluble Poria cocos polysaccharides is of great significance for developing materials using Poria cocos polysaccharides as carriers, and can also provide guidance for the full utilization of Poria cocos residue. Summary of the Invention

[0003] In view of this, the present invention provides a method for preparing Poria cocos polysaccharide gel microspheres and its application, so as to provide an application scenario for alkali-soluble polysaccharides and a method for making full use of Poria cocos residue.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A method for preparing Poria cocos polysaccharide gel microspheres includes the following steps:

[0006] Dissolve Poria cocos polysaccharide in an alkaline solution with a pH of 11-14 to obtain a polysaccharide solution.

[0007] Isooctane was mixed with the first surfactant and stirred to obtain oil phase I;

[0008] The polysaccharide solution was added dropwise to oil phase I and stirred to obtain a water-in-oil system;

[0009] Isooctane and the second surfactant were mixed and stirred to obtain oil phase II;

[0010] Oil phase II was added dropwise to the water-in-oil system and stirred to obtain a mixture;

[0011] Add 1.0 mol / L to 2.0 mol / L HCl solution dropwise to the mixture, stir at 250 rpm to 500 rpm, wash with ethanol and deionized water in sequence, allow to stand and separate into layers to obtain crude Poria cocos polysaccharide gel microspheres.

[0012] Add tert-butanol to the crude Poria cocos polysaccharide gel microspheres, stir, and freeze-dry to obtain Poria cocos polysaccharide gel microspheres.

[0013] Furthermore, the concentration of Poria cocos polysaccharide in the polysaccharide solution is 5 mg / mL to 50 mg / mL.

[0014] Furthermore, the first surfactant is Span85, and the second surfactant is Tween85.

[0015] Furthermore, the mass-to-volume ratio of Span85 to the polysaccharide solution is 1:(5-10), and the mass ratio of Span85 to Tween85 is 2:1.

[0016] Furthermore, the total mass-to-volume ratio of isooctane in oil phases I and II to the polysaccharide solution is 5:(1-3), and the mass ratio of isooctane in oil phase I to isooctane in oil phase II is 10:1.

[0017] Furthermore, the volume ratio of tert-butanol to crude Poria cocos polysaccharide gel microspheres is 2:1, and the stirring conditions are: 25-35℃, 70-90rpm, 1-3 days, during which tert-butanol is replaced every 4-8 hours according to the concentration gradient.

[0018] The above preparation method yields the Poria cocos polysaccharide gel microspheres, which can be used as drug carriers in the pharmaceutical field.

[0019] A method for preparing Poria cocos polysaccharide silver nanogel microspheres includes the following steps: based on the above-mentioned method for preparing Poria cocos polysaccharide gel microspheres, the method further includes adding silver nitrate solution dropwise to the polysaccharide solution to obtain a mixed solution of Poria cocos polysaccharide silver nanospheres, and then performing the remaining identical steps to obtain the Poria cocos polysaccharide silver nanogel microspheres.

[0020] Furthermore, the concentration of the silver nitrate solution is 25mM to 500mM, and the volume ratio of the silver nitrate solution to the polysaccharide solution is 1:10.

[0021] The above preparation method yields poria cocos polysaccharide nanosilver gel microspheres, which can be used as catalysts in wastewater treatment, photocatalytic degradation, and photocatalytic hydrogen production.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] (1) The present invention uses emulsification method, with natural polysaccharides as raw materials, and takes advantage of the characteristics of Poria cocos polysaccharide being alkali-soluble but acid-insoluble. The microspheres are solidified by acid regeneration and self-assembled by intermolecular hydrogen bonds to prepare a natural polysaccharide gel microsphere with good biosafety and stability.

[0024] (2) The morphology and particle size of the poria cocos polysaccharide gel microspheres prepared by the emulsification method of the present invention can be controlled by adjusting the polysaccharide concentration, the ratio of isooctane to polysaccharide solution, the content of surfactant, the acid concentration, the rotation speed, and other conditions.

[0025] (3) The preparation process of this invention is simple, the raw materials are readily available, and it is green and environmentally friendly. It does not change the chemical structure of the polysaccharide or use chemical cross-linking agents.

[0026] (4) The preparation conditions of the poria cocos polysaccharide nano-silver gel microspheres prepared by the present invention are simple, the yield of nano-silver is high, the dispersion is uniform, and the catalytic efficiency is good. Compared with conventional chemical methods, it avoids the use of a variety of toxic chemical reducing agents and dispersants. Compared with the preparation of nano-silver using glucose as a reducing agent (which requires heating to 90°C or above and has a low reduction rate), it can react at room temperature, reacts rapidly, and has a high reduction rate. Attached Figure Description

[0027] Figure 1 The electron microscope image and corresponding particle size distribution map of the microspheres provided in Example 1, as well as the SEM image and corresponding particle size distribution map;

[0028] Figure 2 Electron microscope and SEM images of the microspheres provided for Comparative Example 1;

[0029] Figure 3 The electron microscope image and corresponding particle size distribution map of the microspheres provided in Example 2, as well as the SEM image and corresponding particle size distribution map;

[0030] Figure 4 Electron microscope and SEM images of the microspheres are provided for Comparative Example 2;

[0031] Figure 5 Electron microscope and SEM images of the microspheres are provided for Comparative Example 3;

[0032] Figure 6 Electron microscope and SEM images of the microspheres are provided for Comparative Example 4;

[0033] Figure 7 The electron microscope image and corresponding particle size distribution map of the microspheres provided in Example 3, as well as the SEM image and corresponding particle size distribution map;

[0034] Figure 8 The electron microscope image and corresponding particle size distribution map of the microspheres provided in Example 4, as well as the SEM image and corresponding particle size distribution map;

[0035] Figure 9 The electron microscope image and corresponding particle size distribution map of the microspheres provided in Example 5, as well as the SEM image and corresponding particle size distribution map;

[0036] Figure 10 Electron microscope and SEM images of the microspheres provided in Example 6;

[0037] Figure 11 Electron microscope and SEM images of the microspheres provided in Example 7;

[0038] Figure 12 Electron microscope and SEM images of the microspheres provided in Example 8;

[0039] Figure 13 Electron microscope and SEM images of the microspheres provided in Example 9;

[0040] Figure 14 Electron microscope and SEM images of the microspheres provided in Example 10;

[0041] Figure 15 Electron microscope and SEM images of the microspheres provided in Example 11;

[0042] Figure 16 Electron microscope and SEM images of the microspheres provided in Example 12;

[0043] Figure 17 Electron microscope and SEM images of the microspheres are provided for Comparative Example 5;

[0044] Figure 18 Electron microscope and SEM images of the microspheres are provided for Comparative Example 6;

[0045] Figure 19 Electron microscope and SEM images of the microspheres are provided for Comparative Example 7;

[0046] Figure 20 SEM images of microspheres provided for Comparative Example 8;

[0047] Figure 21 XRD patterns of the silver-loaded microspheres provided in Examples 13, 9, and 10;

[0048] Figure 22 TG images of the silver-loaded microspheres provided in Examples 13, 9, and 10;

[0049] Figure 23 FT-IR images of the silver-loaded microspheres provided in Examples 13, 9, and 10;

[0050] Figure 24 The catalytic efficiency diagram is for the silver-loaded microspheres provided in Example 13. Detailed Implementation

[0051] The present invention will now be described in further detail with reference to specific embodiments, so that those skilled in the art can more clearly understand the present invention.

[0052] Key experimental material sources and physicochemical parameters:

[0053] Poria cocos was supplied by Hubei Chenmei Pharmaceutical Co., Ltd., production batch number: 2121110220;

[0054] The extraction steps for Poria cocos polysaccharides are as follows:

[0055] S1. Pulverize the Poria cocos into small pieces and pass them through an 80-mesh sieve. Then, load the sample into a 150-mesh gauze sample bag and place it in a Soxhlet extractor. Reflux with acetone and ethyl acetate for 6 hours respectively, and collect the defatted residue.

[0056] S2. Take the above defatted residue and add it to 0.9% sodium chloride solution. Heat to 90°C and stir for 4 hours. Collect the filter residue and repeat the process several times. Use the phenol-sulfuric acid method to detect the sugar content until no sugar content can be detected in the filtrate. Collect the secondary residue.

[0057] S3. Take the above secondary filter residue and add it to a 0.5 mol / L NaOH aqueous solution. Stir at 5℃ for 2 hours, collect the filtrate, and repeat twice to collect all the filtrate.

[0058] S4. Take the filtrate from S3 and deproteinize it using the Sevage method at a ratio of filtrate:chloroform:n-butanol = 25:5:1. Stir for 30 minutes and repeat the filtration process 3 times. Collect all the supernatant. Add 99% glacial acetic acid to the supernatant to adjust the pH to neutral and stir continuously until a large amount of precipitate is produced. Collect the precipitate and add 95% ethanol at a mass-volume ratio of 1:1. Mix well and let stand for 6 hours. Collect the precipitate. Take the precipitate after ethanol washing and add distilled water at a mass-volume ratio of 1:10. Stir well and collect the precipitate. Repeat this process 3 times. The resulting precipitate is the crude polysaccharide of Poria cocos.

[0059] S5. Dissolve the above-mentioned crude polysaccharide from Poria cocos in dimethyl sulfoxide (DMSO) to obtain a DMSO solution of crude polysaccharide from Poria cocos with a concentration of 1 mg / mL. Add ultrapure water dropwise using a constant pressure dropping funnel while stirring continuously. Collect the precipitate and freeze-dry it to obtain the Poria cocos polysaccharide.

[0060] Unless otherwise specified, all raw materials used in this invention are existing substances that can be purchased directly from the market.

[0061] Example 1

[0062] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres, specifically including the following steps:

[0063] S1. Dissolve 660 mg of the prepared Poria cocos polysaccharide in 22 mL of 0.5 mol / L NaOH solution to prepare a polysaccharide solution with a concentration of 30 mg / mL.

[0064] S2. Take 50g of isooctane and 2.2g of Span85 and mix them at 500rpm for 1h to obtain oil phase I;

[0065] S3. The polysaccharide solution was added dropwise to the oil phase I using a constant pressure dropping funnel while stirring. The addition was completed in 10 minutes, and stirring was continued at 500 rpm for 1 hour to obtain the water-in-oil system.

[0066] S4. Take 5g of isooctane and 1.1g of Tween85 and mix them at 500rpm for 1h to obtain oil phase II;

[0067] S5. Add oil phase II dropwise to the water-in-oil system while stirring. The addition is completed in 5 minutes. Continue stirring at 500 rpm for 1 hour to obtain the mixture.

[0068] S6. Add 22 mL of 1 mol / L HCl solution dropwise to the mixture while stirring. The addition is completed in 5 min. Continue stirring at 500 rpm for 1 h. After standing for 6 h, wash three times with an equal volume of ethanol and then three times with an equal volume of deionized water. Let stand for layering and filter to obtain crude Poria cocos polysaccharide gel microspheres.

[0069] S7. Add 2 times the volume of tert-butanol (t-BuOH) to the crude Poria cocos polysaccharide gel microspheres and soak for 2-3 days at 30℃ and 80 rpm. During this period, replace t-BuOH 1-3 times every 4-6 hours according to the concentration gradient (20%, 40%, 60%, 80%, 100%, replacing from low to high). Freeze dry to obtain Poria cocos polysaccharide gel microspheres.

[0070] Example 2

[0071] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as in Example 1, except that the 1 mol / L HCl solution in step S6 is replaced with a 2 mol / L HCl solution, while the rest remains unchanged.

[0072] Example 3

[0073] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as those in Example 1, except that the amount of Poria cocos polysaccharide in step S1 is 220 mg, while the rest remain unchanged.

[0074] Example 4

[0075] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as those in Example 1, except that the amount of Poria cocos polysaccharide in step S1 is 1100 mg, while the rest remain unchanged.

[0076] Example 5

[0077] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as those in Example 1, except that: in step S2, Span85 is 4.4g, and in step S4, Tween85 is 2.2g, while the rest remain unchanged.

[0078] Example 6

[0079] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as those in Example 1, except that: in step S1, the amount of Poria cocos polysaccharide is 220 mg, in step S2, the amount of Span85 is 4.4 g, and in step S4, the amount of Tween85 is 2.2 g, with the rest remaining unchanged.

[0080] Example 7

[0081] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as those in Example 1, except that: in step S1, the amount of Poria cocos polysaccharide is 1100 mg, in step S2, the amount of Span85 is 4.4 g, and in step S4, the amount of Tween85 is 2.2 g, with the rest remaining unchanged.

[0082] Example 8

[0083] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as those in Example 1, except that: in step S1, the amount of Poria cocos polysaccharide is 440 mg, in step S2, the amount of Span85 is 4.4 g, and in step S4, the amount of Tween85 is 2.2 g, with the rest remaining unchanged.

[0084] Example 9

[0085] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as those in Example 1, except that: in step S1, the amount of Poria cocos polysaccharide is 110 mg, in step S2, the amount of Span85 is 4.4 g, and in step S4, the amount of Tween85 is 2.2 g, with the rest remaining unchanged.

[0086] Example 10

[0087] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as those in Example 1. The difference is that in step S1, the polysaccharide solution is prepared by dissolving 330 mg of Poria cocos polysaccharide in 11 mL of 0.5 mol / L NaOH solution. The rest remains unchanged.

[0088] Example 11

[0089] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as those in Example 1. The difference is that in step S1, the polysaccharide solution is prepared by dissolving 990 mg of Poria cocos polysaccharide in 33 mL of 0.5 mol / L NaOH solution, and the rest remains unchanged.

[0090] Example 12

[0091] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as in Example 1, except that the stirring rate in steps S2-S6 is changed from 500 rpm to 250 rpm, while the rest remain unchanged.

[0092] Example 13

[0093] This embodiment provides a method for preparing Poria cocos polysaccharide nano-silver gel microspheres, specifically including the following steps:

[0094] S1. Dissolve 440 mg of the prepared Poria cocos polysaccharide in 22 mL of 0.5 mol / L NaOH solution to prepare a polysaccharide solution with a concentration of 20 mg / mL.

[0095] S2. Add 50mM silver nitrate dropwise to the polysaccharide solution and stir for 30 minutes to obtain a Poria cocos polysaccharide nano silver solution.

[0096] S2. Take 50g of isooctane and 2.2g of Span85 and mix them at 500rpm for 1h to obtain oil phase I;

[0097] S3. The Poria cocos polysaccharide nano silver solution was added dropwise to the oil phase I using a constant pressure dropping funnel while stirring. The addition was completed in 10 minutes, and stirring was continued at 500 rpm for 1 hour to obtain the water-in-oil system.

[0098] S4. Take 5g of isooctane and 1.1g of Tween85 and mix them at 500rpm for 1h to obtain oil phase II;

[0099] S5. Add oil phase II dropwise to the water-in-oil system while stirring. The addition is completed in 5 minutes. Continue stirring at 500 rpm for 1 hour to obtain the mixture.

[0100] S6. Add 22 mL of 1 mol / L HCl solution dropwise to the mixture while stirring. The addition is completed in 5 min. Continue stirring at 500 rpm for 1 h. After standing for 6 h, wash three times with an equal volume of ethanol and then three times with an equal volume of deionized water. After standing and separating into layers, filter to obtain crude product of Poria cocos polysaccharide nano-silver gel microspheres.

[0101] S7. Add 2 times the volume of t-BuOH to the crude product of Poria cocos polysaccharide nano-silver gel microspheres, soak for 2-3 days at 30℃ and 80rpm, and replace t-BuOH 1-3 times every 4-6 hours according to the concentration gradient. Freeze dry to obtain Poria cocos polysaccharide nano-silver gel microspheres.

[0102] Comparative Example 1

[0103] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as in Example 1, except that the 1 mol / L HCl solution in step S6 is replaced with a 0.5 mol / L HCl solution, while the rest remains unchanged.

[0104] Comparative Example 2

[0105] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as in Example 1, except that the 1 mol / L HCl solution in step S6 is replaced with acetic acid with a mass fraction of 20%, while the rest remain unchanged.

[0106] Comparative Example 3

[0107] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as those in Example 1, except that the 1 mol / L HCl solution in step S6 is replaced with acetic acid with a mass fraction of 40%, while the rest remain unchanged.

[0108] Comparative Example 4

[0109] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as those in Example 1, except that the 1 mol / L HCl solution in step S6 is replaced with acetic acid with a mass fraction of 80%, while the rest remain unchanged.

[0110] Comparative Example 5

[0111] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as those in Example 1, except that the mass of Span85 in step S2 is 0.74g and the mass of Tween85 in step S4 is 0.37g, while the rest remain unchanged.

[0112] Comparative Example 6

[0113] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as in Example 1, except that the stirring rate in steps S2-S6 is 1000 rpm, while the rest remain unchanged.

[0114] Comparative Example 7

[0115] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as in Example 1, except that Tween85 is not added in step S4, while the rest remain unchanged.

[0116] Comparative Example 8

[0117] This embodiment provides a method for preparing Poria cocos polysaccharide gel microspheres. The steps and raw material sources are basically the same as in Example 1, except that step S7 is removed, while the rest remain unchanged.

[0118] Comparative Example 9

[0119] This embodiment provides a method for preparing Poria cocos polysaccharide nano-silver gel microspheres. The steps and raw material sources are basically the same as those in Example 13, except that the concentration of silver nitrate in step S2 is 100mM, and the rest remain unchanged.

[0120] Comparative Example 10

[0121] This embodiment provides a method for preparing Poria cocos polysaccharide nano-silver gel microspheres. The steps and raw material sources are basically the same as those in Example 13, except that the concentration of silver nitrate in step S2 is 200mM, and the rest remain unchanged.

[0122] Tests of various indicators of Poria cocos polysaccharide gel microspheres

[0123] The morphology and particle size distribution of the Poria cocos polysaccharide gel microspheres prepared in Examples 1-12 and Comparative Examples 1-8 were characterized. The specific steps included:

[0124] 1) Electron microscope

[0125] Take 100-200 μL of the washed microspheres and place them under an inverted microscope to observe their morphology. Use NanoMeasurer 1.2.5 to calculate the particle size distribution.

[0126] 2) Scanning electron microscope

[0127] A small amount of freeze-dried microspheres were placed on conductive adhesive and pressure was applied at 15 kV. The morphology of the microspheres was observed, and the particle size distribution was calculated using NanoMeasurer 1.2.5.

[0128] Results Analysis

[0129] Table 1 Effect of acid concentration on microsphere size distribution

[0130]

[0131] Combining Table 1 and Figure 2-6The results show that the higher the HCl concentration, the larger the overall particle size of the microspheres. However, when the acid concentration is 0.5 mol / L, the microsphere formation is very poor, and almost no microspheres are formed. The microspheres regenerated with acetic acid have poorer microsphere formation. Among them, 80% acetic acid has better microsphere formation than the other two groups. The acid solution has a great influence on the formation of microspheres. In order to ensure good microsphere formation, strong acid (HCl) should be used for regeneration.

[0132] Table 2. Effect of polysaccharide concentration on microsphere size distribution (Span85:polysaccharide concentration = 1:10 (m / v))

[0133]

[0134] Combined with Table 2, Figure 1 , 7 Results 8 show that when the mass-to-volume ratio of Span85 to polysaccharide solution is 1:10, the sugar concentration has little effect on the microsphere size and the difference in particle size distribution is small. However, at 50 mg / mL, the microsphere particle size distribution is uneven.

[0135] Table 3. Effect of polysaccharide concentration on microsphere size distribution (Span85:polysaccharide solution = 1:5 (m / v))

[0136]

[0137] Combined with Table 3, Figure 9-13 The results show that when the mass-to-volume ratio of Span85 to polysaccharide solution is 1:5, the higher the sugar concentration, the larger the microsphere size. Similarly, it can be seen that the microsphere size distribution is uneven at a concentration of 50 mg / mL. Therefore, it is not recommended to have too high a sugar concentration.

[0138] Table 4 Effect of the ratio of Span85 to polysaccharide solution (m / v) on microsphere size distribution

[0139]

[0140]

[0141] Combine Table 4 and Figure 1 , 9 Results 17 show that the higher the content of Span85, the larger the microsphere size. When the ratio of Span85 to water is 1:30, the sphericity is poor and microspheres are basically not formed, but gel fragments are formed.

[0142] Table 5 Effect of rotational speed on microsphere size distribution

[0143]

[0144] Combined with Table 5 and Figure 1 , 16The results in section 18 show that as the rotation speed increases, the microsphere size becomes smaller, but when the rotation speed exceeds 1000 rpm, a microsphere structure cannot be formed.

[0145] Table 6. Effect of the ratio of isooctane to polysaccharide solution (m / v) on the particle size distribution of microspheres.

[0146]

[0147] Combined with Table 6 and Figure 1 , 14 Results 15 show that microspheres can be formed when the ratio of isooctane to polysaccharide solution is 5:(1-3)(m / v). As the ratio of isooctane to polysaccharide solution increases, the particle size of polysaccharide microspheres tends to decrease.

[0148] Depend on Figure 1 , 19 It can be seen that polysaccharide microspheres cannot be formed without the addition of Tween85.

[0149] Depend on Figure 1 , 20 It can be seen that when the Poria cocos polysaccharide gel microspheres are placed in t-BuOH and stirred before freeze-drying, the surface of the microspheres is smooth and the morphology is intact; while the morphology is not as intact and smooth after direct freeze-drying.

[0150] In summary, the present invention achieves a normal distribution of microsphere particle size and a smooth surface by determining appropriate polysaccharide concentration, isooctane to polysaccharide solution ratio, Tween 85 and Span 85 content, acid concentration, rotation speed, and other conditions.

[0151] Data on various indicators of Poria cocos polysaccharide nano-silver gel microspheres

[0152] The various parameters of the Poria cocos polysaccharide nanosilver gel microspheres (silver-loaded microspheres) prepared in Examples 13, 9, and 10 were measured. The specific steps included:

[0153] 1) X-ray diffraction (XRD)

[0154] The crystal structure and characteristic diffraction peaks of silver-loaded microspheres were analyzed using the Rigaku SmartLab SE (Japan). The test angle was 5-90°, and the scan speed was 2° / min. The results are shown in [Figure number missing]. Figure 21

[0155] 2) Thermogravimetric analysis (TG)

[0156] The thermal stability of silver-loaded microspheres was analyzed using a TA TGA550 microscope (USA). Test conditions ranged from 30 to 800℃, with a heating rate of 10℃ / min. Results are shown below. Figure 22 .

[0157] 3) Fourier Transform Infrared Spectroscopy (FT-IR)

[0158] The characteristic functional groups of silver-loaded microspheres were detected and analyzed using a Thermo Scientific Nicolet iS20 scanner (USA), with a scanning range of 400-4000 cm⁻¹. -1 The results are shown Figure 23 .

[0159] Depend on Figure 21 It can be seen that sharp diffraction peaks appear at approximately 38.18°, 44.18°, 64.25°, 77.46°, and 81.70° at 2θ. By consulting the PDF standard card number (PDF04-004-4773) for silver nanoparticles, it was found that the diffraction peaks of the measured AgNPs are completely consistent with the diffraction peaks in the standard spectrum, which also confirms that AgNPs exist in crystalline form. These five diffraction peaks correspond to the five crystal planes of the face-centered cubic structure of the silver nanoparticles (111), (200), (220), (311), and (222), respectively. This indicates that the silver loaded in the microspheres is elemental silver rather than Ag₂O, and the sharp diffraction peaks of the silver-loaded microspheres reflect the good crystal structure of the silver nanoparticles in the silver-loaded microspheres. As the amount of AgNO3 increases, the amount of silver nanoparticles loaded in the microspheres increases, and the diffraction peak intensity of the silver-loaded microspheres gradually increases. The peak intensity of plane (111) in the figure is relatively high, indicating that the microcrystals are mainly oriented on this plane.

[0160] Depend on Figure 22 It can be seen that the weight of the silver-loaded microspheres decreased at 100℃ due to the evaporation of bound water in the sample. The main weight loss region was in the range of 250–400℃, indicating that the polysaccharide was decomposed. Thermogravimetric analysis was performed under a nitrogen atmosphere, and the silver loaded on the microspheres was not oxidized. Therefore, the residual solid content is the mass of the silver nanoparticles in the silver-loaded microspheres. The silver contents of the microspheres were 1.20%, 1.85%, and 7.62%, respectively.

[0161] Depend on Figure 23 It can be seen that the absorption peaks of the silver-loaded microspheres are almost identical at the same positions compared to the blank microspheres, indicating that there are no special functional groups in the microspheres that react significantly with Ag. The silver nanoparticles, after being encapsulated by the microspheres, possess a certain shielding ability; therefore, the infrared absorption intensity is slightly reduced. Compared to the blank microspheres, the silver-loaded microspheres show a higher absorption peak at 3419 cm⁻¹. -1 The absorption shifts to the lower field region and the peak intensity decreases, indicating that -OH participates in the covalent reaction during the formation of silver nanoparticles.

[0162] The catalytic performance of Poria cocos polysaccharide nano-silver gel microspheres was tested.

[0163] The catalytic performance of the Poria cocos polysaccharide nanosilver gel microspheres prepared in Examples 13, 9, and 10 was determined, specifically including the following steps:

[0164] At 25℃, 2.0 mL of 0.4 mol / L sodium borohydride (NaBH4) solution and 0.5 mg of Poria cocos polysaccharide nano-silver gel microspheres were uniformly mixed. N2 was bubbled through the system for 30 min to remove O2 from the reaction system. Then, 0.5 mL of p-nitrophenol aqueous solution (0.4 mmol / L) was added to start the reaction. Finally, samples were taken at different time points and analyzed by a UV-Vis spectrophotometer.

[0165] The catalytic performance was evaluated using the reduction reaction of NaBH4 with p-nitrophenol. As the reaction proceeded, the solution color gradually changed from yellow to colorless, therefore the absorbance of the solution at different time points also varied (see results). Figure 24 ).

[0166] Depend on Figure 24 It can be seen that: due to the absorption peak intensity (A) of 4-nitrophenol t The concentration of the reaction solution (C) is directly proportional to the concentration of A0. t and C0), that is, A t / A0=C t / C0, while the reaction rate constant can be derived from ln(A) t The slope of the straight line obtained by plotting / A0) against reaction time t is shown. It can be seen that the higher the AgNO3 concentration, the faster the catalytic reaction rate, because the higher the AgNO3 concentration, the higher the silver content in the microspheres.

[0167] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing Poria cocos polysaccharide gel microspheres, characterized in that, Includes the following steps: Dissolve Poria cocos polysaccharides in an alkaline solution with a pH of 11-14 to obtain a polysaccharide solution; Isooctane was mixed with the first surfactant and stirred to obtain oil phase I; The polysaccharide solution was added dropwise to oil phase I and stirred to obtain a water-in-oil system; Isooctane and the second surfactant were mixed and stirred to obtain oil phase II; Oil phase II was added dropwise to the water-in-oil system and stirred to obtain a mixture; Add 1.0 mol / L to 2.0 mol / L HCl solution dropwise to the mixture, stir at 250 rpm to 500 rpm, wash with ethanol and deionized water in sequence, allow to stand and separate into layers to obtain crude Poria cocos polysaccharide gel microspheres. Add tert-butanol to the crude product of Poria cocos polysaccharide gel microspheres, stir, freeze dry, and obtain Poria cocos polysaccharide gel microspheres; The first surfactant is Span85, and the second surfactant is Tween85.

2. The preparation method according to claim 1, characterized in that, The concentration of Poria cocos polysaccharide in the polysaccharide solution is 5 mg / mL to 50 mg / mL.

3. The preparation method according to claim 1, characterized in that, The mass-to-volume ratio of Span85 to polysaccharide solution is 1:(5~10), and the mass ratio of Span85 to Tween85 is 2:

1.

4. The preparation method according to claim 1, characterized in that, The total isooctane content in oil phases I and II, and the volume ratio of isooctane to polysaccharide solution, is 5:(1~3), and the mass ratio of isooctane in oil phase I to isooctane in oil phase II is 10:

1.

5. The preparation method according to claim 1, characterized in that, The volume ratio of tert-butanol to crude poria cocos polysaccharide gel microspheres was 2:

1. The stirring conditions were 25-35℃, 70-90rpm, and 1-3 days. During this period, the tert-butanol was replaced every 4-8 hours according to the concentration gradient.

6. The application of the Poria cocos polysaccharide gel microspheres prepared by the preparation method according to any one of claims 1-5 as a drug carrier.

7. A method for preparing Poria cocos polysaccharide nano-silver gel microspheres, characterized in that, The method includes the following steps: based on the preparation method described in claim 1, it further includes adding silver nitrate solution dropwise to the polysaccharide solution to obtain a mixed solution of Poria cocos polysaccharide and silver nanoparticles. The remaining steps are the same, thus obtaining Poria cocos polysaccharide and silver nanoparticle gel microspheres.

8. The preparation method according to claim 7, characterized in that, The concentration of the silver nitrate solution is 25mM~500mM, and the volume ratio of the silver nitrate solution to the polysaccharide solution is 1:

10.

9. The application of the Poria cocos polysaccharide nanosilver gel microspheres prepared by the preparation method according to claim 7 or 8 as a catalyst in wastewater treatment and photocatalytic degradation.

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