Biomass self-assembled porous microspheres regulated and controlled by carboxymethyl cellulose as well as preparation method and application of biomass self-assembled porous microspheres

Abstract

The invention discloses a biomass self-assembled porous microsphere regulated and controlled by carboxymethyl cellulose as well as a preparation method and application of the biomass self-assembled porous microsphere. The method comprises the following steps: heating adenine powder in a constant-temperature water bath, stirring and dissolving the adenine powder in deionized water, mixing oxalic acid powder with the adenine powder to prepare an adenine / oxalic acid self-assembled nanofiber mixed solution, slowly dropwise adding carboxymethyl cellulose solutions with different concentrations into the mixed solution, standing and cooling at room temperature, and then centrifuging and freeze-drying to obtain the adenine / oxalic acid self-assembled nanofiber. The biomass porous microspheres regulated and controlled by the carboxymethyl cellulose can be obtained. The method is simple and convenient in process and short in reaction time, the used materials are all plant-based components contained in a human body, and the method has the characteristics of low toxicity, environmental protection and the like, and has a wide application prospect in the fields of biomedical materials such as drug loading and the like.

Description

Technical Field

[0001] The present invention relates to the fields of biological and medical materials science, and in particular to a biomass self-assembled porous microsphere regulated by carboxymethyl cellulose, and a preparation method and application thereof. Background Art

[0002] Adenine (A) is a purine nucleobase and a building block of DNA and RNA. Its structure consists of a pyrimidine ring fused with an imidazole ring, along with an amino (-NH2) active site. Due to these properties, adenine exhibits a propensity for self-assembly (forming supramolecular structures through hydrogen bonding and π-π stacking), biological activity (participating in cellular metabolism and gene expression regulation), and targeted recognition (specific pairing with complementary bases). Therefore, it is often used as a matrix for biomedical materials. For example, Chinese invention patent CN116836165B discloses the derivatization of curcumin with a purine group, improving the bioavailability of the material while maintaining the inherent benefits of curcumin.

[0003] Hydrogen bonding is a weak, non-covalent bond formed by the electrostatic interaction between proton donors (such as -NH, -OH) and acceptors (electronegative atoms such as O and N). Hydrogen bonding assembly is a process in which molecules spontaneously arrange into ordered structures driven by intermolecular hydrogen bonding interactions. This force is directional and selective, and can guide molecules to form specific supramolecular structures (such as fibers, layers, or networks) under mild conditions. Therefore, it is spontaneity, reversibility, structural controllability, and biocompatibility. Oxalic acid (OA) is a simple dicarboxylic acid that can act as both a proton donor and an acceptor, forming hydrogen bond structures with the amino and ring nitrogen of adenine. Oxalic acid and adenine are both environmentally friendly small molecules, which facilitates the preparation of environmentally friendly materials under mild conditions and simple methods.

[0004] Carboxymethyl cellulose (CMC) is a product obtained by modifying cellulose with carboxymethyl etherification, which contains hydrophilic carboxylic acid groups (-CH2COO -), has the characteristics of excellent water solubility, high biocompatibility, and degradability. It also has film-forming and gelling capabilities, so it is often used as an important raw material for the preparation of bio-friendly materials. At present, the application status of carboxymethyl cellulose in the biomedical field includes: drug delivery, wound dressing, tissue engineering scaffold materials, etc. The Chinese invention patent with publication number CN119604285A discloses that sodium carboxymethyl cellulose is used as an adsorbent to prepare a pharmaceutical composition containing a protein hydrolysis targeting chimera (PROTAC) compound; the Chinese invention patent with publication number CN119604274A discloses that cross-linked sodium carboxymethyl cellulose is used as a disintegrant to prepare an oral preparation containing active pharmaceutical ingredient particles. Carboxymethyl cellulose, as a hydrophilic, flexible long-chain molecular anion, can adsorb or coat other molecules in aqueous solution to form a dynamic network. At the same time, it can regulate the self-assembly behavior of adenine and oxalic acid through electrostatic effects and steric hindrance.

[0005] Chinese invention patent publication number CN119591066A discloses highly stable porous hydroxyapatite microspheres, their preparation method, and applications. By using thermodynamically driven self-assembly of hydroxyapatite particles, the resulting porous hydroxyapatite microspheres can be used as an auxiliary for bone tissue repair and filling, as a drug delivery carrier, or as a tissue engineering scaffold. However, the assembly method is complex, requiring the addition of a porogen and high-temperature calcination, resulting in a cumbersome process. Therefore, a more environmentally friendly and user-friendly method for preparing biomass porous microspheres is needed to address these issues. Summary of the Invention

[0006] The present invention provides a biomass self-assembled porous microsphere regulated by carboxymethyl cellulose, and its preparation method and application, aiming to provide a green and environmentally friendly, efficient self-assembly preparation method with controllable pore structure, and solve the problems of difficult preparation and limited application scenarios of adenine self-assembly materials in the prior art.

[0007] The present invention adopts the following technical solutions:

[0008] The present invention provides a method for preparing biomass self-assembled porous microspheres regulated by carboxymethyl cellulose, comprising the following steps:

[0009] (1) Dissolve adenine powder in deionized water by heating and stirring in a water bath to prepare an adenine solution;

[0010] (2) adding anhydrous oxalic acid to the prepared adenine solution, continuing heating and stirring to prepare an adenine / oxalic acid self-assembled nanofiber mixed solution;

[0011] (3) adding carboxymethyl cellulose into deionized water and stirring to dissolve to prepare a carboxymethyl cellulose solution;

[0012] (4) slowly adding the carboxymethyl cellulose solution dropwise to the heated and stirred adenine / oxalic acid self-assembled nanofiber mixed solution, continuing heating and stirring, and then standing and cooling at room temperature;

[0013] (5) The product obtained by cooling at room temperature is centrifuged and then freeze-dried to obtain biomass self-assembled porous microspheres regulated by carboxymethyl cellulose.

[0014] Preferably, in step (1), the concentration of the adenine solution is 0.04 mol / L-0.12 mol / L, more preferably 0.06 mol / L-0.10 mol / L.

[0015] Preferably, in step (1), the temperature of heating and stirring is 70-90°C, more preferably 90°C.

[0016] Preferably, in step (2), the molar ratio of anhydrous oxalic acid to adenine is in the range of 1-3:3; more preferably 1:2.

[0017] Preferably, in step (2), the temperature of heating and stirring is 70-90°C, more preferably 90°C.

[0018] Preferably, in step (3), the concentration of the carboxymethyl cellulose solution is 0.6 wt%-2.0 wt%, more preferably 0.6 wt%-1.0 wt%.

[0019] Preferably, in step (4), the temperature of heating and stirring is 70-90°C, more preferably 90°C.

[0020] The above preparation method obtains a kind of biomass self-assembled porous microspheres regulated by carboxymethyl cellulose. The microspheres are formed by adenine / oxalic acid self-assembled fibers entangled with each other. The microspheres are mostly regular spherical or oblate ellipsoidal. They have a rich porous structure, including mesopores, mesopores and macropores. The diameter of the microspheres ranges from 2μm to 20μm, and the pore size ranges from tens of nanometers to hundreds of nanometers.

[0021] The present invention provides a green and environmentally friendly and easy-to-operate method, which induces hydrogen bond self-assembly between adenine and oxalic acid by temperature, and prepares a biomass self-assembled porous microsphere with pore size that can be regulated by carboxymethyl cellulose. Specifically, after adding carboxymethyl cellulose solution to adenine / oxalic acid self-assembled nanofibers, the carboxylic acid group of carboxymethyl cellulose can form an electrostatic interaction with the amino group of adenine, regulating the self-assembly process, and at the same time, the steric hindrance effect of the carboxymethyl cellulose chain can also suppress the excessive aggregation of the self-assembled nanofibers to achieve homogenization of pore size (mainly based on 100-200nm pore size). The self-assembled nanofibers are entangled under the regulation of carboxymethyl cellulose to form biomass porous microspheres with mesopores to macropores. Therefore, the regulation of carboxymethyl cellulose causes adenine / oxalic acid to self-assemble into porous microspheres, further enhancing its application potential in the fields of biomedical materials such as drug loading and wound dressings.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] (1) The material is biocompatible and environmentally friendly. The porous microspheres in the present invention are formed by the entanglement of self-assembled fibers of adenine and oxalic acid under the induction of carboxymethyl cellulose. Adenine, as a nucleic acid base, has a natural metabolic pathway and low immunogenicity, and is suitable for green medical materials; oxalic acid is a natural component in many plants and can be rapidly mineralized in the soil, with a short half-life and no bioaccumulation risk; carboxymethyl cellulose, as a derivative of plant cellulose, has a wide range of raw materials and can be naturally degraded. Therefore, the three materials involved in the present invention all have the advantages of natural origin and degradability, and have excellent biocompatibility and environmental friendliness.

[0024] (2) The preparation method is simple to operate and environmentally friendly. The preparation method of the present invention is a temperature-induced hydrogen bond self-assembly under water bath heating conditions, and the required maximum temperature is only 90°C. Therefore, it has the characteristics of simple operation, low energy consumption, and environmental protection.

[0025] (3) The microspheres have a regular shape, a rich pore structure, and an adjustable pore size. The biomass microspheres prepared by the present invention are regular spherical or ellipsoidal in shape, with a rich pore structure ranging from mesopores to macropores. At the same time, the size and pore size of the microspheres can be controlled by adjusting the concentration of added carboxymethyl cellulose. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0027] Figure 1 This is a scanning electron microscope (SEM) image of the biomass self-assembled porous microspheres regulated by carboxymethyl cellulose obtained in Example 1 of the present invention.

[0028] Figure 2 This is a scanning electron microscope (SEM) image of the biomass self-assembled porous microspheres regulated by carboxymethyl cellulose obtained in Example 2 of the present invention.

[0029] Figure 3 This is a scanning electron microscope (SEM) image of the biomass self-assembled porous microspheres regulated by carboxymethyl cellulose obtained in Example 3 of the present invention.

[0030] Figure 4 This is a scanning electron microscope (SEM) image of the biomass self-assembled porous microspheres regulated by carboxymethyl cellulose obtained in Example 4 of the present invention. DETAILED DESCRIPTION

[0031] The above contents of the present invention are further described in detail below through examples, but the present invention should not be considered to be limited to the following examples. All technologies realized based on the above contents of the present invention belong to the scope of the present invention.

[0032] Example 1

[0033] A method for preparing biomass self-assembled porous microspheres regulated by carboxymethyl cellulose, comprising the following steps:

[0034] (1) Place adenine powder in a 90°C constant temperature water bath and heat and stir until completely dissolved to prepare a 0.10 mol / L adenine solution;

[0035] (2) adding anhydrous oxalic acid to the prepared adenine solution, continuing heating and stirring, to prepare an adenine / oxalic acid self-assembled nanofiber mixed solution, wherein the molar ratio of anhydrous oxalic acid to adenine is 1:2;

[0036] (3) slowly adding a 0.8 wt% carboxymethyl cellulose solution dropwise to the heated and stirred adenine / oxalic acid self-assembled nanofiber mixed solution, continuing heating and stirring at 90° C. for 15 minutes and then standing and cooling at room temperature;

[0037] (4) The product obtained by cooling at room temperature is centrifuged and then freeze-dried to obtain biomass self-assembled porous microspheres regulated by carboxymethyl cellulose.

[0038] Figure 1 This is a scanning electron microscope (SEM) image of the biomass self-assembled porous microspheres regulated by carboxymethyl cellulose obtained in Example 1. It can be seen that the microspheres prepared under this condition are regular spherical, with a diameter of the microspheres ranging from 8 μm to 15 μm, and a rich pore structure on the surface. The pore diameter is in the range of 20 nm to 400 nm, with most pores of 50-100 nm.

[0039] Example 2

[0040] A method for preparing biomass self-assembled porous microspheres regulated by carboxymethyl cellulose, comprising the following steps:

[0041] (1) Place adenine powder in a constant temperature water bath at 85°C and heat with stirring until completely dissolved to prepare a 0.08 mol / L adenine solution;

[0042] (2) adding anhydrous oxalic acid to the prepared adenine solution, continuing heating and stirring, to prepare an adenine / oxalic acid self-assembled nanofiber mixed solution, wherein the molar ratio of anhydrous oxalic acid to adenine is 1:2;

[0043] (3) slowly adding a 0.6 wt% carboxymethyl cellulose solution dropwise to the heated and stirred adenine / oxalic acid self-assembled nanofiber mixed solution, continuing to heat and stir at 85°C for 15 minutes and then standing to cool at room temperature;

[0044] (4) The product obtained by cooling at room temperature is centrifuged and then freeze-dried to obtain biomass self-assembled porous microspheres regulated by carboxymethyl cellulose.

[0045] Figure 2 This is a scanning electron microscope (SEM) image of the biomass self-assembled porous microspheres regulated by carboxymethyl cellulose obtained in Example 2. It can be seen that the microspheres prepared under this condition are regular spherical, the microsphere diameter is in the range of 6μm to 20μm, the surface is relatively dense, and the pore size is in the range of 20nm to 200nm, with the majority of pores being 100-200nm.

[0046] Example 3

[0047] A method for preparing biomass self-assembled porous microspheres regulated by carboxymethyl cellulose, comprising the following steps:

[0048] (1) Place adenine powder in a 90°C constant temperature water bath and heat and stir until completely dissolved to prepare a 0.10 mol / L adenine solution;

[0049] (2) adding anhydrous oxalic acid to the prepared adenine solution, continuing heating and stirring, to prepare an adenine / oxalic acid self-assembled nanofiber mixed solution, wherein the molar ratio of anhydrous oxalic acid to adenine is 1:1;

[0050] (3) slowly adding a 1.0 wt% carboxymethyl cellulose solution dropwise to the heated and stirred adenine / oxalic acid self-assembled nanofiber mixed solution, continuing heating and stirring at 90° C. for 15 minutes and then standing and cooling at room temperature;

[0051] (4) The product obtained by cooling at room temperature is centrifuged and then freeze-dried to obtain biomass self-assembled porous microspheres regulated by carboxymethyl cellulose.

[0052] Figure 3 This is a scanning electron microscope (SEM) image of the biomass self-assembled porous microspheres regulated by carboxymethyl cellulose obtained in Example 3. It can be seen that the microspheres prepared under this condition are spherical or ellipsoidal, with a diameter of the microspheres ranging from 3 μm to 15 μm, a rich fiber structure can be observed on the surface, and a pore size ranging from 40 nm to 600 nm, with most pores ranging from 100 to 300 nm.

[0053] Example 4

[0054] A method for preparing biomass self-assembled porous microspheres regulated by carboxymethyl cellulose, comprising the following steps:

[0055] (1) Place adenine powder in a constant temperature water bath at 85°C and heat with stirring until completely dissolved to prepare a 0.08 mol / L adenine solution;

[0056] (2) adding anhydrous oxalic acid to the prepared adenine solution, continuing heating and stirring, to prepare an adenine / oxalic acid self-assembled nanofiber mixed solution, wherein the molar ratio of anhydrous oxalic acid to adenine is 1:2;

[0057] (3) slowly adding a 1.5 wt% carboxymethyl cellulose solution dropwise to the heated and stirred adenine / oxalic acid self-assembled nanofiber mixed solution, continuing heating and stirring at 85°C for 15 minutes and then standing to cool at room temperature;

[0058] (4) The product obtained by cooling at room temperature is centrifuged and then freeze-dried to obtain biomass self-assembled porous microspheres regulated by carboxymethyl cellulose.

[0059] Figure 4 This is a scanning electron microscope (SEM) image of the biomass self-assembled porous microspheres regulated by carboxymethyl cellulose obtained in Example 4. It can be seen that the microspheres prepared under these conditions are walnut-shaped spheres with a diameter in the range of 3 μm to 10 μm. A rich pore structure can be observed on the surface, and the pore size is relatively uniform, ranging from 100 nm to 200 nm, with most pores in the range of 150 to 200 nm.

[0060] It can be seen from the above examples that the microspheres prepared in these examples have regular shapes, rich pore structures, and adjustable pore sizes. This shows that the biomass microspheres prepared by the method of the present invention have rich pore structures ranging from mesopores to macropores, and the size and pore size of the microspheres can be regulated by adjusting the concentration of added carboxymethyl cellulose. From the SEM images of Examples 1 to 4, it can be seen that the spherical microspheres in Example 1 are the most regular, and the surface of the microspheres presents a rich pore structure. At this time, the loading rate is good, which shows that the higher the concentration of carboxymethyl cellulose is, the better. The optimal concentration of carboxymethyl cellulose in the present invention is 0.8wt%.

[0061] Taking the antibacterial agent polyhexamethyleneguanidine salt as an example, the drug loading and antibacterial properties of the biomass self-assembled porous microspheres prepared by the embodiment of the present invention under the regulation of different concentrations of carboxymethyl cellulose were explored. The concentration of polyhexamethyleneguanidine hydrochloride is 1wt%, the concentration of carboxymethyl cellulose is 0.6-1.4wt%, the strain is Staphylococcus aureus, and the antibacterial effect is expressed by the minimum inhibitory concentration (MIC). The results show that the samples loaded with polyhexamethyleneguanidine hydrochloride under the regulation of different concentrations of carboxymethyl cellulose all show good antibacterial properties, with a MIC of 25mg / L, and the MIC of the pure polyhexamethyleneguanidine hydrochloride control group is 12.5mg / L. However, since the actual mass of polyhexamethyleneguanidine hydrochloride in the composite sample accounts for less than 30%, it can be proved that the biomass self-assembled porous microspheres regulated by carboxymethyl cellulose have improved their antibacterial properties after being compounded with polyhexamethyleneguanidine hydrochloride, which also reflects the application potential of the biomass self-assembled porous microspheres prepared by the method of the present invention in the field of drug loading.

Claims

1. A method for preparing biomass self-assembled porous microspheres regulated by carboxymethyl cellulose, characterized in that: The steps include: (1) Dissolve adenine powder in deionized water by heating and stirring in a water bath to prepare an adenine solution; (2) adding anhydrous oxalic acid to the prepared adenine solution, continuing heating and stirring to prepare an adenine / oxalic acid self-assembled nanofiber mixed solution; (3) adding carboxymethyl cellulose into deionized water and stirring to dissolve to prepare a carboxymethyl cellulose solution; (4) slowly adding the carboxymethyl cellulose solution dropwise to the heated and stirred adenine / oxalic acid self-assembled nanofiber mixed solution, continuing heating and stirring, and then standing and cooling at room temperature; (5) The product obtained by cooling at room temperature is centrifuged and then freeze-dried to obtain biomass self-assembled porous microspheres regulated by carboxymethyl cellulose.

2. The method for preparing biomass self-assembled porous microspheres regulated by carboxymethyl cellulose according to claim 1, characterized in that: In step (1), the concentration of the adenine solution is in the range of 0.04 mol / L to 0.12 mol / L.

3. The method for preparing biomass self-assembled porous microspheres regulated by carboxymethyl cellulose according to claim 1, characterized in that: In step (1), the temperature of the heating and stirring is 70-90°C.

4. The method for preparing biomass self-assembled porous microspheres regulated by carboxymethyl cellulose according to claim 1, characterized in that: In step (2), the molar ratio of anhydrous oxalic acid to adenine is 1-3:

3.

5. The method for preparing biomass self-assembled porous microspheres regulated by carboxymethyl cellulose according to claim 1, characterized in that: In step (2), the temperature of the heating and stirring is 70-90°C.

6. The method for preparing biomass self-assembled porous microspheres regulated by carboxymethyl cellulose according to claim 1, characterized in that: In step (3), the concentration of the carboxymethyl cellulose solution is 0.6 wt%-2.0 wt%.

7. The method for preparing biomass self-assembled porous microspheres regulated by carboxymethyl cellulose according to claim 1, characterized in that: In step (4), the temperature of the heating and stirring is 70-90°C.

8. Biomass self-assembled porous microspheres obtained by the preparation method according to any one of claims 1 to 7 and regulated by carboxymethyl cellulose.

9. The biomass self-assembled porous microspheres regulated by carboxymethyl cellulose according to claim 8, characterized in that: The microspheres have a rich porous structure including mesopores, medium pores and macropores. The diameter of the microspheres ranges from 2 to 20 μm, and the pore size ranges from tens of nanometers to hundreds of nanometers.

10. Use of the biomass self-assembled porous microspheres regulated by carboxymethyl cellulose according to claim 8 in the preparation of drug-loaded materials and wound dressings.

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