Highly biocompatible surface-roughened microsphere adsorbents, methods of making and medical uses thereof

Abstract

The application discloses a high-biocompatibility surface-creped microsphere adsorbent and a preparation method and medical application thereof. The surface-creped microsphere adsorbent is obtained by preparing first microspheres, preparing a first surface modification liquid, preparing second microspheres and creped treatment, and can reduce the absorption of phosphorus in the gastrointestinal tract and reduce the risk of causing side effects when used as a phosphorus adsorbent for treating hyperphosphatemia. Meanwhile, the surface-creped microsphere adsorbent can significantly increase the residence time in the intestinal tract, thereby improving the efficiency of phosphorus adsorption, and can be discharged outside the body through the intestinal tract in the form of feces, and will not cause adverse reactions to the human body. In addition, a large number of experiments prove that the surface-creped microsphere adsorbent can effectively improve the calcium-phosphorus metabolic imbalance and vascular calcification when used as a medical calcium-phosphorus binding agent, and thus can provide a feasible and better alternative strategy for preventing and treating hyperphosphatemia and its cardiovascular complications.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical technology, specifically relating to a method for preparing a highly biocompatible surface-wrinkled microsphere adsorbent, and further relating to the surface-wrinkled microsphere adsorbent prepared by this method. Furthermore, this invention also relates to the medical application of the aforementioned highly biocompatible surface-wrinkled microsphere adsorbent as a phosphorus adsorbent for treating hyperphosphatemia, and other medical applications as adsorbents for treating other diseases. Background Technology

[0002] Phosphorus is one of the essential substances for the human body, participating in vital physiological activities such as energy metabolism, important tissue formation, signal transduction, regulation of biomolecule activity, and acid-base balance. Most phosphorus in the human body is found in bones and teeth, with the remainder in cells and blood plasma. Generally, the human body ingests phosphorus through diet, and its excretion is primarily handled by the kidneys. Normal plasma phosphorus levels fluctuate between 0.81 and 1.45 mmol / L, depending on diet, age, and sex. Under normal circumstances, healthy kidneys maintain phosphorus balance by regulating phosphorus excretion, keeping serum phosphorus levels within the normal range. However, in patients with chronic kidney disease (CKD), abnormal kidney function leads to a decrease in glomerular filtration rate and disordered phosphorus metabolism, resulting in plasma phosphorus concentrations exceeding 1.45 mmol / L, thus causing hyperphosphatemia.

[0003] Hyperphosphatemia itself does not produce symptoms, but it can affect the concentration of calcium ions in the blood, causing a decrease in calcium levels and thus having various effects on patients with chronic kidney disease. These effects include causing hyperparathyroidism, leading to renal osteodystrophy; reducing the activity of 1-α-hydroxylase in proximal tubular cells, resulting in decreased production of 1,25-dihydroxyvitamin D3 and impaired bone calcification; and inducing vascular calcification and other abnormal soft tissue calcification by induced endothelial cell apoptosis and oxidative stress. Therefore, effectively controlling plasma phosphorus concentration is crucial for managing the condition in patients with chronic kidney disease. Currently, the main clinical treatments for hyperphosphatemia are twofold: limiting phosphorus intake and promoting phosphorus excretion, specifically through dietary phosphate restriction, blood purification, and oral phosphate binders. However, limiting dietary phosphorus intake and blood purification cannot completely remove excess phosphorus from the body; therefore, the use of phosphate binders to treat hyperphosphatemia in patients with chronic kidney disease has become a very necessary approach.

[0004] To date, phosphate binders can be categorized into traditional phosphate binders and non-aluminum, non-calcium phosphate binders. Traditional phosphate binders include aluminum-containing phosphate binders and calcium-containing phosphate binders. The earliest phosphate binders were aluminum-containing phosphate binders, invented in the 1970s. However, the accumulation of aluminum ions in the body can lead to neurotoxicity and bone abnormalities, thus limiting their application. Subsequently, calcium-containing phosphate binders, such as calcium carbonate and calcium acetate, were developed. These calcium-containing phosphate binders not only have good phosphorus-lowering effects but are also inexpensive and have high patient compliance. However, the high calcium load associated with calcium-containing phosphate binders can lead to hypercalcemia and tissue calcium deposition, increasing vascular calcification and cardiovascular risk. In recent years, non-calcium, non-aluminum phosphate binders have been widely used clinically, such as magnesium-containing phosphate binders, iron-containing phosphate binders, sevelamer carbonate, and lanthanum carbonate. Among these, magnesium-containing phosphate binders have a weaker effect but a strong laxative effect; iron-containing phosphate binders have a low phosphorus-binding capacity and cannot be used long-term; sevelamer carbonate, as an anion exchange resin, binds to phosphorus in the gastrointestinal tract and is not absorbed by the body, effectively reducing serum phosphorus and FGF-23 levels, but its adverse effects on the gut microbiota and gastrointestinal reactions caused by its high expansion rate (such as nausea, vomiting, and severe constipation) hinder its widespread clinical application. Lanthanum carbonate dissociates in gastric acid and binds to phosphorus through ionic bonds to form hydrophobic compounds, effectively reducing serum phosphorus levels, but long-term intake of lanthanum may have toxic side effects on the liver, bones, and nervous system.

[0005] In summary, existing phosphate binders have significant drawbacks. Developing a new, highly efficient phosphate binder is of great importance for the treatment of hyperphosphatemia. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides a highly biocompatible surface-wrinkled microsphere adsorbent. When used as a phosphorus adsorbent to treat hyperphosphatemia, it reduces gastrointestinal phosphorus absorption and lowers the risk of side effects. Simultaneously, it significantly increases the residence time in the intestines, thereby enhancing phosphorus adsorption efficiency. Furthermore, it can be excreted through the intestines in feces without causing adverse reactions in the human body. In addition, extensive experimental evidence demonstrates that this surface-wrinkled microsphere adsorbent, when used as a medical calcium-phosphate binder, can effectively improve calcium-phosphorus metabolic imbalance and vascular calcification, thus potentially providing a feasible and promising alternative strategy for the prevention and treatment of hyperphosphatemia and its cardiovascular complications.

[0007] In a first aspect of the present invention, a method for preparing a highly biocompatible surface-wrinkled microsphere adsorbent is provided, comprising the following steps:

[0008] S1. Preparation of the first microspheres: Prepare a first polymer solution and use the first polymer solution to prepare the first microspheres;

[0009] S2. Preparation of the first surface modification solution: Prepare the second polymer solution, then add the first soluble metal salt. After the first soluble metal salt is completely dissolved and becomes a homogeneous solution, reduce the first soluble metal salt to the corresponding first metal nanoparticles to obtain the first surface modification solution.

[0010] S3. Preparation of the second microsphere: Add the first microsphere prepared in step S1 to the first surface modification liquid prepared in step S2, and stir for more than 0.5 hours to obtain the second microsphere;

[0011] S4. Preparation of surface-wrinkled microsphere adsorbent: The second microsphere prepared in step S3 is stirred in a shrinkage solution to wrinkle it, thereby obtaining the surface-wrinkled microsphere adsorbent of the present invention.

[0012] In this process, the polymer in the first polymer solution (i.e., the first polymer) and the polymer in the second polymer solution (i.e., the second polymer) are attracted to each other, so that the second polymer can coat the surface of the first microsphere.

[0013] In the preparation method of the highly biocompatible surface-wrinkled microsphere adsorbent of the present invention, the second polymer solution contains a second polymer and metal nanoparticles that have an attractive attraction to the first polymer in the first polymer solution. The intermolecular forces between the second polymer and the first polymer are attractive forces, which can be any one or more of hydrogen bonds, electrostatic forces, and van der Waals forces. The metal nanoparticles or unreduced metal ions interact with the first polymer and / or the second polymer, which further strengthens the bond between the second polymer and the first microspheres. Furthermore, the presence of metal nanoparticles results in a larger mechanical modulus for the shell formed by the second polymer coating the first microsphere compared to the first microsphere. During the process of the second polymer coating the first microsphere, there is a difference in swelling properties between the second polymer containing rigid metal nanoparticles (i.e., the rigid metal nanoparticle layer) adsorbed on the surface of the second microsphere and the elastic first microsphere. Moreover, due to interfacial stress and critical stress in the shrinkage liquid, structural instability occurs, leading to the formation of wrinkled structures on the surface of the second microsphere to achieve mechanical equilibrium, i.e., surface wrinkling to stabilize the surface. After surface wrinkling, the highly biocompatible surface-wrinkled microsphere adsorbent of this invention can be obtained. A schematic diagram of the entire wrinkling process is shown below. Figure 4 Clearly, the method for preparing highly biocompatible surface-wrinkled microsphere adsorbents of this invention is simple, operates under mild conditions, and does not require stringent operational control, providing extremely favorable preconditions for future large-scale applications. Furthermore, it should be noted that the order of steps S1 and S2 in the method of this invention can be adjusted; there is no strict rule regarding the order of these two steps, and they can be implemented according to the actual situation of the manufacturer.

[0014] Preferably, in the above preparation method, the first polymer in the first polymer solution may be a natural polymer and / or a synthetic polymer.

[0015] More preferably, in the above preparation method, the natural polymer is selected from, but not limited to, chitosan, chitin, silk fibroin, hyaluronic acid, carboxylated cellulose, inulin, protein, starch, pectin, guar gum, alginic acid, sodium alginate, seaweed, sodium alginate, lignin, natural rubber, polyglutamic acid, or modified natural polymers, etc., wherein the modified natural polymers can be modified by amylation, hydroxylation, amidation, etc.

[0016] More preferably, in the above preparation method, the synthesized polymer is a polar polymer so that it can be more tightly bonded to the second polymer through intermolecular forces.

[0017] More preferably, in the above preparation method, the polar polymer is selected from, but not limited to, one or more of polylactic acid-hydroxyacetic acid copolymer, polystyrene, polylactic acid, polyhydroxybutyrate, polyethyleneimine, polydimethylamine polyacrylic acid, and polybenzenesulfonic acid.

[0018] In this invention, the first polymer is not limited to the specific selections mentioned above and can be rationally selected according to specific application requirements. Furthermore, the natural polymer refers to a high molecular weight compound existing in nature, formed by multiple small molecular units linked by covalent bonds. It can be obtained in nature without artificial synthesis, but the main chain of the modified natural polymer is still that of the natural polymer; therefore, it is classified as a natural polymer here. The synthetic polymer, in contrast to the natural polymer, is a polymer synthesized artificially, and there are many types. The polymers specifically exemplified above are for illustrative purposes only.

[0019] It should be noted that the highly biocompatible surface-wrinkled microsphere adsorbent of the present invention requires high biocompatibility, and based on the application of the treatment of hyperphosphatemia, the first polymer is more likely to be a natural polymer or a modified natural polymer. However, if the highly biocompatible surface-wrinkled microsphere adsorbent of the present invention needs to be used in other fields such as water treatment, a synthetic polymer may be selected as appropriate.

[0020] Preferably, in the above preparation method, the solvent in the first polymer solution can be an organic solvent and / or an inorganic solvent, as long as it can dissolve the first polymer.

[0021] More preferably, in the above preparation method, the organic solvent is selected from, but not limited to, one or more organic solvents selected from, but not limited to, alcohols such as ethanol and isopropanol, ketones such as acetone and methyl ethyl ketone, ethers such as diethyl ether, propylene oxide and tetrahydrofuran, aliphatic hydrocarbons such as pentane and hexane, chlorinated hydrocarbons such as dichloromethane and chloroform, alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene and toluene, and sulfoxides such as dimethyl sulfoxide.

[0022] In a further preferred embodiment, in the above preparation method, in view of the principle of convenient source, the inorganic solvent is water, which is inexpensive and easy to obtain.

[0023] In this preparation method, the solvent used for the first polymer solution is not particularly limited, as long as it can dissolve the first polymer. However, in order to facilitate the preparation of the first microspheres, a highly volatile organic solvent is preferred.

[0024] Preferably, in the above preparation method, the mass fraction of the first polymer in the first polymer solution is 0.5-20%. At this concentration, the viscosity of the first polymer solution is sufficient to prepare the first microspheres smoothly. If the concentration is too high, the first polymer may not dissolve completely or the viscosity of the prepared first polymer solution may be too high, making it impossible to prepare the first microspheres using the equipment. If the concentration is too low, the efficiency of preparing the first microspheres is too low.

[0025] Preferably, in the above preparation method, the obtained first microspheres are dry, meaning that the mass percentage of water or non-aqueous solvent in the first microspheres is less than 0.1% of the total mass of the first microspheres, or they do not contain water or other solvents. This allows for the large-scale preparation of the first microspheres for subsequent use and storage, thereby providing conditions for the industrial preparation of the present invention. Regarding the drying method, conventional drying methods in the art can be used, such as air drying, freeze drying, oven drying, etc., and are not limited thereto. Furthermore, the particle size of the obtained first microspheres is not strictly limited and can be customized according to usage requirements.

[0026] Preferably, in the above preparation method, the method for preparing the first microspheres using the first polymer solution can be spray drying, droplet microfluidics, or emulsion polymerization.

[0027] Furthermore, in the above preparation method, the first microspheres are prepared using the first polymer solution via droplet microfluidics. This is because preparing the first microspheres using droplet microfluidics allows for better control of the microsphere size and uniformity, and the microspheres exhibit excellent dispersibility. In particular, the chitosan microspheres prepared using the chitosan solution via droplet microfluidics also demonstrate excellent strength and pH-responsive behavior; they swell in acidic solutions and shrink in alkaline solutions. This pH-responsive characteristic allows the microspheres to rapidly respond to environmental changes and interact with other components under given conditions.

[0028] Furthermore, when the first polymer solution is prepared into the first microspheres using the spray spheroidizing method, the specific process is as follows: the first polymer solution, which is the dispersed phase, is sprayed into droplets using a spraying device and then solidified to obtain the first microspheres.

[0029] More preferably, during the spray sphere-making process, the inlet temperature is 30-300℃, preferably 50-200℃, the outlet temperature is 20-60℃, preferably 30-50℃, and the atomizer speed is 2000-30000 RPM, preferably 5000-20000 RPM. Controlling these parameters ensures rapid solvent evaporation and allows for the regulation of the prepared microsphere particle size.

[0030] More preferably, during the spray ball-making process, the spray device sprays the dispersed phase into droplets with a particle size of 50-600 μm, and droplets of corresponding particle sizes can also be prepared according to specific application requirements.

[0031] More preferably, the curing method for the microspheres obtained after spraying can be thermosetting, chemical curing, or ultraviolet curing, so as to make the obtained microspheres more stable. The specific curing method depends on the type of the first polymer.

[0032] More preferably, when the curing method of the microspheres obtained after spraying is chemical curing, the sprayed droplets need to be sprayed into the crosslinking liquid first, followed by curing and crosslinking, removing the liquid, washing and drying to obtain the first microspheres, or the crosslinking agent or the crosslinking agent and the initiator are added to the first polymer solution as the dispersed phase, and curing and crosslinking can be carried out during or after spraying.

[0033] The crosslinking liquid contains a crosslinking agent, or a crosslinking agent and an initiator. The amount and type of the initiator are conventional in the art, as long as they can accelerate the curing of the microspheres.

[0034] Furthermore, the crosslinking agent is selected from, but not limited to, one or more of glutaraldehyde, epichlorohydrin, ethylene glycol diglycidyl ether, calcium chloride, dimethylene diacrylate, dimethyl methacrylate, polyethylene glycol, mercaptoethanol, and 1,4-butanediol diacrylate. The specific crosslinking agent selected depends on the application scenario and the type of the first polymer. If used for medical applications, a crosslinking agent that is harmless to the human body and has high biocompatibility is selected; if used for other applications, the specific type of crosslinking agent can be selected based on the type of the first polymer and the crosslinking efficiency.

[0035] Specifically, if the first polymer is chitosan, the curing method is chemical curing, and the selected crosslinking agent is usually glutaraldehyde. The principle is that the amino groups in chitosan react with the carbonyl groups in glutaraldehyde via a Schiff base reaction, forming a crosslinked structure between chitosan molecules, increasing the intermolecular connection points and forming a three-dimensional gel network structure. If the first polymer is sodium alginate, the selected crosslinking agent is usually calcium chloride. Calcium ions will form ionic bonds with the carboxyl groups in sodium alginate, forming a crosslinked structure. This crosslinked structure leads to the formation of a three-dimensional network structure between sodium alginate molecules, causing the solution to gradually gel into a solid gel.

[0036] Specifically, both the crosslinking agent and the initiator can be commercially available products, such as Irgacure 2959, Darocur 1173, BPO peroxide, etc., which can be selected as appropriate.

[0037] The method for removing liquid is a conventional method in the art, such as centrifugation or filtration, and is not strictly limited. The washing solution used can be a conventional organic or inorganic solvent in the art, such as water, ethanol, xylene, etc., and the washing can be performed two, three, four, or more times to remove unreacted cross-linking agents or other excess substances. In addition, after washing the microspheres, they can be dried for long-term storage. The drying method is also a commonly used method in the art, such as baking, air drying, or freeze drying, to remove the liquid contained within.

[0038] Furthermore, when the first polymer solution is used to prepare the first microspheres using droplet microfluidics, the specific process is as follows: the first polymer solution is injected into the microchannel of the droplet microfluidics device as both the dispersed and continuous phases. Microdroplets are formed at the intersection of the dispersed and continuous phases and flow into the collection phase. Subsequently, solidification, liquid removal, and washing are performed to obtain the first microspheres.

[0039] It should be noted that before continuously injecting the dispersed and continuous phases, the various components of the droplet microfluidic device, such as the microfluidic chip, syringe, capillary, needle, and PVC tubing, need to be connected, and the syringe should be mounted on the mechanical pump so that these components can realize the function of preparing the first microspheres according to this invention. Furthermore, the microchannels used in the droplet microfluidic device can be conventional channels, such as Y-shaped channels, T-shaped channels, fluid focusing channels, concentric capillary channels, and double T-shaped channels, and the microchannel diameter is also conventionally set in the art, such as 20-500 μm, without strict limitations, as long as the function of preparing microdroplets is achieved.

[0040] Furthermore, in the process of preparing the first microspheres from the first polymer solution using droplet microfluidics, the microdroplets formed at the intersection of the dispersed and continuous phases have a particle size of 100-600 μm. The droplet size formed in droplet microfluidics can be adjusted in various ways, such as by adjusting the flow rate.

[0041] More preferably, in droplet microfluidics, the method for solidifying microdroplets can be thermosetting, chemical curing, ultraviolet curing, etc., and the specific curing method and conditions depend on the type of the first polymer. The method for removing the liquid is a conventional method in the art, such as centrifugation or filtration, and is not strictly limited. The washing liquid used can be a conventional organic or inorganic solvent in the art, such as water, ethanol, xylene, etc., and the washing can be performed two, three, four, or more times to remove unreacted crosslinking agents or excess surfactants. In addition, after washing the microspheres, they can also be dried for long-term storage. The drying method is also a commonly used method in the art, such as baking, air drying, freeze drying, etc., to remove the solvents contained therein.

[0042] Furthermore, the continuous phase and the collected phase are incompatible with the polymer solution. More specifically, the solvents of the continuous phase and the collected phase can be organic solvents and / or inorganic solvents (such as water), wherein the organic solvents are selected from, but are not limited to, one or more organic solvents selected from, but not limited to, alcohols such as ethanol and isopropanol, ketones such as acetone and methyl ethyl ketone, ethers such as diethyl ether, propylene oxide, and tetrahydrofuran, aliphatic hydrocarbons such as n-octane, isooctane, n-heptane, pentane, and hexane, chlorinated hydrocarbons such as dichloromethane and chloroform, alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene and toluene, and sulfoxides such as dimethyl sulfoxide.

[0043] Furthermore, the collection phase contains a crosslinking agent to achieve chemical solidification of the microdroplets. The amount and type of crosslinking agent, as well as the conditions for chemical solidification, are not strictly limited and are conventional settings in the field, as long as the solidification of the microspheres can be achieved.

[0044] Furthermore, the collection phase also contains an initiator to accelerate the chemical solidification of the microdroplets. The amount and type of initiator are conventional settings in the art, as long as they can accelerate the solidification of the microspheres.

[0045] Furthermore, the crosslinking agent is selected from, but not limited to, one or more of glutaraldehyde, epichlorohydrin, ethylene glycol diglycidyl ether, calcium chloride, dimethylene diacrylate, dimethyl methacrylate, polyethylene glycol, mercaptoethanol, and 1,4-butanediol diacrylate. The specific crosslinking agent selected depends on the application scenario and the type of the first polymer. If used for medical applications, a crosslinking agent that is harmless to the human body and has high biocompatibility is selected; if used for other applications, the specific type of crosslinking agent can be selected based on the type of the first polymer and the crosslinking efficiency.

[0046] Furthermore, the continuous phase contains a surfactant, and the mass fraction and type of the surfactant are not strictly limited and are conventional settings in the art, as long as the microspheres can be stably dispersed.

[0047] Furthermore, the surfactant is selected from, but not limited to, one or more of sodium dodecyl sulfonate, sodium hexadecyl sulfonate, Span 80, Tween 60, Tween 80, octanol polyoxyethylene ether, and dodecyl alcohol polyoxyethylene ether. The specific surfactant selected depends on the application scenario and the type of the first polymer. If used for medical applications, a surfactant that is harmless to the human body and has high biocompatibility is selected; if used for other applications, the specific type of surfactant can be selected based on cost.

[0048] Furthermore, the flow rate ratio (flow velocity ratio) of the continuous phase to the dispersed phase is 10:1-1:500, preferably 50:1-1:300.

[0049] More preferably, the flow rate of the continuous phase is 50-1500 mL / h, and the flow rate of the first polymer solution is 1-3 mL / h.

[0050] In microfluidics, the droplet size can be controlled by adjusting the flow rates of the continuous and dispersed phases, thereby controlling the size of the first microsphere. Preparing the first microsphere using microfluidics offers advantages such as simplicity, speed, and ease of operation, and the resulting microspheres exhibit good dispersibility and uniform size, making it a relatively good method for preparing first microspheres.

[0051] Furthermore, when preparing the first microspheres from the first polymer solution using emulsion polymerization, the specific process is as follows: a solution that is incompatible with the first polymer solution is added as a continuous phase to the first polymer solution as a dispersed phase. After the system is mixed evenly, the dispersed phase is formed into microdroplets, which are then solidified, the liquid is removed, and the microspheres are washed to obtain the first microspheres.

[0052] Furthermore, when preparing the first microspheres from the first polymer solution using emulsion polymerization, the continuous phase of the solution immiscible with the first polymer solution comprises an emulsifier and a solvent. The solvent can be an organic solvent and / or an inorganic solvent (such as water). The organic solvent is selected from, but is not limited to, alcohols such as ethanol and isopropanol, ketones such as acetone and methyl ethyl ketone, ethers such as diethyl ether, propylene oxide, and tetrahydrofuran, aliphatic hydrocarbons such as n-octane, isooctane, n-heptane, pentane, and hexane, chlorinated hydrocarbons such as dichloromethane and trichloromethane, alicyclic hydrocarbons such as cyclohexane, and aromatic hydrocarbons such as benzene and toluene. One or more organic solvents, such as dimethyl sulfoxide, are sulfoxides. The surfactant is selected from, but is not limited to, one or more of polyvinyl alcohol, sodium dodecyl sulfonate, sodium hexadecyl sulfonate, Span 80, Tween 60, Tween 80, octanol polyoxyethylene ether, and dodecyl alcohol polyoxyethylene ether. The specific surfactant selected depends on the application scenario and the type of the first polymer. If used for medical applications, a surfactant that is harmless to the human body and has high biocompatibility is selected. If used for other applications, the specific type of surfactant can be selected based on cost, and the amount of emulsifier used is the conventional amount used in the art.

[0053] Furthermore, when preparing the first microspheres from the first polymer solution using emulsion polymerization, the continuous phase of the solution that is incompatible with the first polymer solution further includes a crosslinking agent to solidify the microdroplets.

[0054] Furthermore, when preparing the first microspheres from the first polymer solution using emulsion polymerization, the continuous phase of the solution that is incompatible with the first polymer solution also includes an initiator to initiate or accelerate the crosslinking of the microdroplets. The type and amount of the initiator are well known in the art and can be selected depending on the type of crosslinking agent and curing requirements.

[0055] Furthermore, the amount and type of crosslinking agent used in the emulsion polymerization process are not strictly limited and are conventional settings in the field, as long as the microspheres can be solidified.

[0056] Furthermore, the crosslinking agent is selected from, but not limited to, one or more of glutaraldehyde, epichlorohydrin, ethylene glycol diglycidyl ether, calcium chloride, dimethylene diacrylate, dimethyl methacrylate, polyethylene glycol, mercaptoethanol, and 1,4-butanediol diacrylate. The specific crosslinking agent selected depends on the application scenario and the type of the first polymer. If used for medical applications, a crosslinking agent that is harmless to the human body and has high biocompatibility is selected; if used for other applications, the specific type of crosslinking agent can be selected based on the type of the first polymer and the crosslinking efficiency.

[0057] In this invention, the method of dispersing the first polymer solution as the dispersed phase into microdroplets during the preparation of the first microspheres by emulsion polymerization is a conventional emulsification method in the art, such as mechanical emulsification, ultrasonic emulsification, high-pressure emulsification, etc. The particle size of the formed microdroplets is 50-500 μm. Alternatively, droplets of a corresponding particle size can be prepared according to the specific application requirements, which can be controlled by adjusting the conditions in the emulsification process.

[0058] In addition, the method of curing microdroplets during the preparation of the first microspheres by emulsion polymerization can be determined according to the type of the first polymer, such as thermosetting, chemical curing, ultraviolet curing, etc., so as to make the obtained microspheres more stable. The specific curing conditions also depend on the specific situation, such as the type of the first polymer, which is well known in the art.

[0059] Furthermore, when the curing process requires the participation of a crosslinking agent and / or initiator, the crosslinking agent and / or initiator can be added to the continuous phase. The curing conditions are then determined based on the type of crosslinking agent and the first polymer, which is well known in the art and will not be described in detail here.

[0060] As an example, if the first polymer is chitosan, the curing method is chemical curing, and the selected crosslinking agent is usually glutaraldehyde. Specifically, the amino groups in chitosan react with the carbonyl groups in glutaraldehyde via a Schiff base reaction, forming a crosslinked structure between chitosan molecules, increasing the intermolecular connection points and forming a three-dimensional gel network structure. If the first polymer is sodium alginate, the selected crosslinking agent is usually calcium chloride. Calcium ions will form ionic bonds with the carboxyl groups in sodium alginate, forming a crosslinked structure. This crosslinked structure leads to the formation of a three-dimensional network structure between sodium alginate molecules, causing the solution to gradually gel into a solid gel. It should be noted that during the preparation of the first microspheres using emulsion polymerization, after the microdroplets are cured, the solid-liquid separation method is a conventional method in the art, such as centrifugation or filtration, and is not strictly limited. The washing liquid used can be a conventional organic or inorganic solvent in the art, such as water, ethanol, xylene, etc., and the washing can be performed two, three, four, or multiple times to remove unreacted crosslinking agents or other excess substances. In addition, the microspheres can be dried after washing in order to preserve them for a long time. The drying method is also a common method in the field, such as baking, air drying, freeze drying, etc., in order to remove the solvent contained therein.

[0061] In addition, the particle size of the first microsphere obtained in step S1 can be determined according to specific circumstances and customized according to usage requirements.

[0062] Preferably, in step S2, the second polymer in the second polymer solution is a polymer that has an attractive attraction to the polymer in the first polymer solution, i.e., the first polymer, and can be an anionic polymer and / or a cationic polymer. In terms of source, both anionic and cationic polymers can be natural or synthetic polymers, and there are no strict limitations; the choice can be made according to application requirements.

[0063] More preferably, the anionic polymer is selected from, but not limited to, one or more of polyacrylic acid, polyesteric acid, polybenzenesulfonic acid, sodium alginate, polyglutamic acid, anionic polyacrylamide, polymethacrylic acid and its salts, and polyvinyl sulfonic acid and its salts.

[0064] More preferably, the cationic polymer is selected from, but not limited to, one or more of polyethyleneimine, cationic polyacrylamide, polyquaternary ammonium salt polymers, polydimethylamine, chitosan, and aminoated cellulose.

[0065] Preferably, the solvent in the second polymer solution can be an organic solvent and / or an inorganic solvent (such as water). The organic solvent is selected from, but is not limited to, one or more of the following: alcohols such as ethanol and isopropanol; ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether, propylene oxide, and tetrahydrofuran; aliphatic hydrocarbons such as n-octane, isooctane, n-heptane, pentane, and hexane; chlorinated hydrocarbons such as dichloromethane and chloroform; alicyclic hydrocarbons such as cyclohexane; aromatic hydrocarbons such as benzene and toluene; and sulfoxides such as dimethyl sulfoxide. There is no strict limitation on the type of organic solvent, as long as it can dissolve the second polymer.

[0066] More preferably, the mass fraction of the second polymer in the second polymer solution is 0.01-10%, more preferably 0.01-8%. At this concentration, the viscosity of the second polymer solution allows the second polymer to effectively and smoothly coat the first microspheres. If the concentration is too high, the second polymer may not dissolve completely and may not effectively coat the first microspheres; if the concentration is too low, the amount of coating the first microspheres will be insufficient and the efficiency will be too low.

[0067] Preferably, in step S2, the first soluble metal salt is a metal salt of a metal element selected from, but not limited to, gold, silver, copper, platinum, nickel, iron, or manganese that is soluble in the solvent of the second polymer solution, such as silver nitrate or gold nitrate.

[0068] More preferably, the mass fraction of the first soluble metal salt after complete dissolution in the second polymer solution is 0.01-10%, more preferably 0.01-5%. At this concentration, the metal particles can be effectively dispersed in the second polymer solution, ensuring their adsorption capacity and providing rigid support for subsequent surface wrinkling.

[0069] Preferably, in step S2, the reduction of the first soluble metal salt into corresponding first metal nanoparticles is carried out by a first reducing agent. The first reducing agent is a substance capable of reducing metal ions in the soluble metal salt into metal nanoparticles, such as sodium sulfite, glycine, or sodium borohydride. The amount of reducing agent used is sufficient to reduce all metal ions in the soluble metal salt, but an excess may also be used. Based on the silver ion content in the silver salt, the reducing agent needs to reduce as many silver ions as possible to silver. The molar ratio of the amount of electrons transferred by the reducing agent in the redox reaction to silver ions is greater than or equal to 1. For cost-saving considerations, the molar ratio of the amount of electrons transferred by the reducing agent in the redox reaction to silver ions is in the range of 1-3.

[0070] More preferably, the particle size of the first metal nanoparticles is 7-50 nm, more preferably 15-30 nm. If the particle size of the first metal nanoparticles is too large, the specific surface area will decrease, making them more prone to aggregation and resulting in poor microsphere coating. If the particle size of the first metal nanoparticles is too small, the mechanical properties will decrease, the strength will be low, and the mechanical stress required to form wrinkles will not be achieved.

[0071] The presence of the first metal nanoparticles is crucial to the highly biocompatible surface-wrinkled microsphere adsorbent of the present invention, providing support for the surface wrinkled tissue, thereby enabling the microspheres finally prepared by the present invention to have a wrinkled structure, which is very similar to the surface structure of the human gastrointestinal tract, and still has good stability in an acidic environment.

[0072] More preferably, the step between step S2 and step S3 further includes the following step:

[0073] S22 Preparation of the second surface modification solution: Prepare the third polymer solution, then add the second soluble metal salt. After the second soluble metal salt is completely dissolved and becomes a homogeneous solution, reduce the second soluble metal salt to the corresponding second metal nanoparticles to obtain the second surface modification solution.

[0074] S23 Preparation of the third surface modification solution: Prepare the fourth polymer solution, then add the third soluble metal salt. After the third soluble metal salt is completely dissolved and becomes a homogeneous solution, reduce the third soluble metal salt to the corresponding third metal nanoparticles to obtain the third surface modification solution.

[0075]

[0076] S2(N-1) Preparation of the Nth surface modification solution: Prepare the Nth polymer solution, then add the N-1th soluble metal salt. After the N-1th soluble metal salt is completely dissolved and becomes a homogeneous solution, reduce the N-1th soluble metal salt to the corresponding N-1th metal nanoparticles to obtain the N-1th surface modification solution.

[0077] S2(N) Preparation of the Nth surface modification solution: Prepare the N+1th polymer solution, then add the Nth soluble metal salt. After the Nth soluble metal salt is completely dissolved and becomes a homogeneous solution, reduce the Nth soluble metal salt to the corresponding Nth metal nanoparticles to obtain the Nth surface modification solution.

[0078] Where N is an integer greater than 1, the polymers in the second polymer solution (i.e., the second polymer), the polymers in the third polymer solution (i.e., the third polymer), the polymers in the fourth polymer solution (i.e., the fourth polymer), ..., the polymers in the Nth polymer solution (i.e., the Nth polymer), and the polymers in the (N+1)th polymer solution (i.e., the N+1)th polymer are mutually independent and sequentially attracted to each other. That is, the polymers in the second polymer solution (i.e., the second polymer) and the polymers in the third polymer solution (i.e., the third polymer), the polymers in the third polymer solution (i.e., the third polymer), and the polymers in the fourth polymer solution (i.e., the fourth polymer), ..., the polymers in the Nth polymer solution (i.e., the Nth polymer), and the polymers in the (N+1)th polymer solution (i.e., the N+1)th polymer are respectively attracted to each other so that the second polymer, the third polymer, the fourth polymer, ..., the Nth polymer, and the (N+1)th polymer are sequentially coated on the first microsphere.

[0079] More preferably, the third polymer, the fourth polymer, ..., the Nth polymer, and the N+1th polymer can be independently anionic polymers and / or cationic polymers. In terms of source, both anionic and cationic polymers can be natural or synthetic polymers, with no strict limitations, and can be selected according to application requirements.

[0080] It should also be noted that if N is an even number, the second, fourth, ..., and Nth polymers can be the same or different; the third, ..., and (N+1)th polymers can be the same or different. If N is an odd number, the second, fourth, ..., and (N+1)th polymers can be the same or different; the third, ..., and Nth polymers can be the same or different. In other words, when N is 6, the second, fourth, and sixth polymers can be the same or different; the third, fifth, and seventh polymers can be the same or different.

[0081] More preferably, the anionic polymer is selected from, but not limited to, one or more of polyacrylic acid, polyesteric acid, polybenzenesulfonic acid, sodium alginate, polyglutamic acid, anionic polyacrylamide, polymethacrylic acid and its salts, and polyvinyl sulfonic acid and its salts.

[0082] More preferably, the cationic polymer is selected from, but not limited to, one or more of polyethyleneimine, cationic polyacrylamide, polyquaternary ammonium salt polymers, polydimethylamine, chitosan, and aminoated cellulose.

[0083] More preferably, the mass fraction of the polymer in the third polymer solution (i.e., the third polymer), the polymer in the fourth polymer solution (i.e., the fourth polymer), ..., the polymer in the Nth polymer solution (i.e., the Nth polymer), and the polymer in the (N+1)th polymer solution (i.e., the N+1th polymer) can independently be 0.01-10%, preferably 0.01-8%. At this concentration, the viscosity of the second polymer solution allows the second polymer to effectively and smoothly coat the first microspheres. If the concentration is too high, the second polymer may not dissolve completely and may not effectively coat the first microspheres; if the concentration is too low, the amount of coating the first microspheres will be insufficient and the efficiency will be too low.

[0084] Preferably, in step S2, the second soluble metal salt, the third soluble metal salt, ..., the (N-1)th soluble metal salt, and the Nth soluble metal salt are metal salts that may be the same or different, and can be independently selected from, but not limited to, one of gold, silver, copper, platinum, nickel, iron, or manganese, which are soluble in the solvent of the corresponding polymer solution, such as silver nitrate, gold nitrate, etc.

[0085] More preferably, the mass fraction of the second soluble metal salt, the third soluble metal salt, ..., the (N-1)th soluble metal salt, and the Nth soluble metal salt after complete dissolution in the corresponding polymer solution is independently 0.01-10%, more preferably 0.01-5%. At this concentration, the metal particles can be effectively dispersed in the second polymer solution, ensuring their adsorption amount and providing rigid support for subsequent surface wrinkling.

[0086] Preferably, in step S2, the reduction of the second soluble metal salt, the third soluble metal salt, ..., the (N-1)th soluble metal salt, and the Nth soluble metal salt into corresponding second metal nanoparticles, third metal nanoparticles, ..., the (N-1)th metal nanoparticles, and the Nth metal nanoparticles is carried out by the same or different reducing agents. The reducing agent is a substance capable of reducing metal ions in the soluble metal salt into metal nanoparticles, such as sodium sulfite, glycine, sodium borohydride, etc. The amount of reducing agent used is sufficient to reduce all metal ions in the soluble metal salt, but it can also be in excess. The particle size of the corresponding metal nanoparticles can be the same or different, ranging from 7-50 nm, preferably 15-30 nm. Based on the silver ion content in silver salts, the reducing agent needs to reduce silver ions to silver as much as possible. The molar ratio of the amount of electrons transferred by the reducing agent in the redox reaction to silver ions is greater than or equal to 1. For cost-saving considerations, the molar ratio of the amount of electrons transferred by the reducing agent in the redox reaction to silver ions is in the range of 1-3.

[0087] Preferably, the solvents in the third polymer solution, the fourth polymer solution, ..., the Nth polymer solution, and the N+1th polymer solution may be the same or different, and may be independently organic solvents and / or inorganic solvents (such as water). The organic solvents are selected from, but are not limited to, alcohols such as ethanol and isopropanol, ketones such as acetone and methyl ethyl ketone, ethers such as diethyl ether, propylene oxide, and tetrahydrofuran, aliphatic hydrocarbons such as n-octane, isooctane, n-heptane, pentane, and hexane, chlorinated hydrocarbons such as dichloromethane and chloroform, alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene and toluene, and sulfoxides such as dimethyl sulfoxide. There is no strict limitation on the type of organic solvent, as long as it can dissolve the corresponding polymer.

[0088] Preferably, in the above preparation method, before adding the first microspheres prepared in step S1 to the first surface modification liquid prepared in step S2, the first microspheres prepared in step S1 are swollen in a swelling liquid, and more preferably, swelling equilibrium is reached. The swelling equilibrium can be determined by microscopy, that is, the swelling equilibrium is considered to have been reached when the particle size of the first microsphere no longer increases by microscopy. The purpose of the swelling is mainly to first increase the surface area of ​​the microspheres, and then coat the rigid nanoparticles and polymers on the surface of the microspheres.

[0089] More preferably, in the above preparation method, in step S3, the swelling solution can be a conventional organic or inorganic solution, wherein the inorganic solvent can be, for example, water, a dilute hydrochloric acid solution with a concentration of less than 20%, etc., and the organic solvent can be one or more of the following: alcohols such as ethanol, isopropanol, etc.; ketones such as acetone, methyl ethyl ketone, etc.; ethers such as diethyl ether, propylene oxide, tetrahydrofuran, etc.; aliphatic hydrocarbons such as pentane, hexane, etc.; chlorinated hydrocarbons such as dichloromethane, trichloromethane, etc.; alicyclic hydrocarbons such as cyclohexane, etc.; aromatic hydrocarbons such as benzene, toluene, etc.; and sulfoxides such as dimethyl sulfoxide, etc. The type of swelling solution is only required to swell the first microsphere.

[0090] More preferably, in the above preparation method, in step S3, the mass ratio of the swelling solution to the mass of the first microsphere is greater than 20:1. The mass of the swelling solution relative to the first microsphere is sufficient to ensure that the first microsphere is fully swollen. The specific amount of swelling solution required depends on the type and amount of the first polymer.

[0091] Preferably, in the above preparation method, the mass ratio of the second polymer to the first microsphere in the first surface-modified liquid in step S3 is 1:1 to 1:10. Too much or too little of the second polymer relative to most of the first microspheres will affect the size of the surface wrinkles. To ensure sufficient polymer coating of the first microspheres, firstly, the entire process of step S3 must be long enough; secondly, it is necessary to ensure that the liquid contains the second polymer after step S3 is completed. Generally, the adsorption amount on the surface of microspheres is very low relative to their own mass. Therefore, through extensive experiments, we have proven that within this mass ratio range, sufficient polymer coating can be ensured on the surface of the first microspheres.

[0092] Preferably, in the above preparation method, the stirring in step S3 can be carried out in a shaker, a stirring paddle, or other instruments that can achieve uniform mixing, and the stirring speed is 500-2000 rpm, so as to accelerate the coating of the second polymer.

[0093] Preferably, in the above preparation method, after adding the first surface-modifying liquid and stirring for more than 0.5 hours to achieve the second polymer coating of the first microspheres in step S3, the following step is further included:

[0094] S32 Coating with the Third Polymer: After the first microspheres are coated with the second polymer, the second surface modification liquid is added and stirred for more than 0.5 hours to obtain microspheres coated with the third polymer.

[0095] S33 Coating with the Fourth Polymer: After the first microsphere is coated with the third polymer, the third surface modification liquid is added and stirred for more than 0.5 hours to obtain microspheres coated with the fourth polymer.

[0096]

[0097] S3(N-1) Coating of the Nth polymer: After the N-1th polymer is used to coat the first microspheres, the N-1th surface modification liquid is added and stirred for more than 0.5 hours to obtain microspheres coated with the Nth polymer.

[0098] S3(N) Coating of the N+1th Polymer: After the first microspheres are coated with the Nth polymer, the Nth surface modification liquid is added and stirred for more than 0.5 hours to obtain microspheres coated with the N+1th polymer, i.e., the second microspheres.

[0099] Where N is an integer greater than 1.

[0100] Alternatively, preferably, in the above preparation method, after adding the first surface-modifying liquid and stirring for more than 0.5 hours to achieve the second polymer coating of the first microspheres in step S3, the following step is further included:

[0101] S311 Coating with the Third Polymer: After the first microspheres are coated with the second polymer, the second surface modification liquid is added and stirred for more than 0.5 hours to obtain microspheres coated with the third polymer.

[0102] S321 Repeated Coating: Repeating step S3 (coating the second polymer) and step S31 (coating the third polymer) M times yields microspheres sequentially coated with the second polymer and the dot polymer, i.e., the second microspheres.

[0103] Where M is an integer greater than or equal to 1.

[0104] Clearly, the entire process of step S3 can be regarded as a complete LBL self-assembly process. During the assembly process, the surface of the first microsphere can be sequentially coated with the second polymer, the third polymer, the fourth polymer, ..., the Nth polymer, the N+1th polymer, or sequentially and cyclically coated with the second polymer and the dot polymer, depending on the usage environment and requirements, in order to achieve functional expansion and broaden the application prospects.

[0105] Preferably, in the above steps, the mass ratio of the third polymer in the third polymer solution of the second surface modification liquid, the mass of the fourth polymer in the fourth polymer solution of the third surface modification liquid, ..., the mass of the Nth polymer in the Nth polymer solution of the N-1th surface modification liquid, and the mass of the N+1th polymer in the Nth surface modification liquid to the mass of the first microsphere can be the same or different, and can be independently 1:1 to 1:10.

[0106] Preferably, the stirring in the above steps can be carried out in a shaker, a stirring paddle, or other instruments that can achieve uniform mixing, and the stirring speed is 500-2000 rpm to speed up the coating process.

[0107] Preferably, in the above steps, after each polymer coating, the process further includes liquid removal and washing to remove polymer that has not been adsorbed onto the microsphere surface. This is more conducive to the subsequent polymer coating, preventing unadsorbed polymer from hindering the coating of subsequent polymers. The liquid removal method is conventional in the art, such as centrifugation or filtration, and is not strictly limited. The washing solution used can be a conventional organic or inorganic solvent in the art, such as water, ethanol, xylene, etc., and the washing can be performed two, three, four, or multiple times to remove excess substances.

[0108] Preferably, after the polymer coating is completed on the surface of the first microsphere, liquid removal, washing, and / or drying are required. The liquid removal method is conventional in the art, such as centrifugation or filtration, and is not strictly limited. The washing solution can be a conventional organic or inorganic solvent in the art, such as water, ethanol, xylene, etc., and the washing can be performed two, three, four, or multiple times to remove excess substances. The drying method is also commonly used in the art, such as baking, air drying, or freeze drying, to remove the contained liquid. The dried microspheres can be stored and transported for a long time. If the second microsphere is to be dried, the dried microsphere should be fully swollen before proceeding to step S4.

[0109] Preferably, in the above preparation method, the shrinking liquid is an organic solvent such as ethanol, methanol, chloroform, dimethyl sulfoxide, etc., or an inorganic solvent such as a sodium hydroxide solution with a mass fraction of 4-15%, etc. Exemplarily, the shrinking liquid can be determined according to the characteristics of the first polymer. For example, chitosan has pH responsiveness, and its shrinkage is caused by its properties in sodium hydroxide solution. Obviously, when the first polymer is chitosan, the shrinking liquid is an aqueous sodium hydroxide solution. Alternatively, the shrinking liquid can also achieve the purpose of desolventizing and shrinking to create wrinkles by displacing the solvent within the first microspheres. That is, in this invention, the shrinking liquid is a liquid that reduces the volume of the microspheres without affecting their chemical properties.

[0110] In other words, the choice of the shrinking liquid should be based on the material of the first microsphere. It needs to have good permeability, enabling dehydration or shrinkage through changes in the internal structure of the microsphere, thereby achieving surface wrinkling. Extensive experimental evidence shows that when the first polymer is polylactic-co-glycolic acid copolymer (PLGA), sodium alginate, or hyaluronic acid, and the shrinking liquid is ethanol and / or methanol, the goal of surface wrinkling through microsphere shrinkage can be achieved.

[0111] The use of a shrinking solution is essential for the formation of wrinkles. Its function is to displace the solvent inside the microspheres, causing them to shrink. During shrinkage, a stress imbalance occurs between the rigid metal nanoparticle layer on the surface of the microspheres and the core microsphere, resulting in wrinkles. Additionally, if the first polymer is pH-responsive and the shrinking solution is acidic or alkaline, microsphere shrinkage will also occur. For example, chitosan microspheres are pH-responsive, swelling in acidic solutions and shrinking in alkaline solutions. Therefore, using an alkaline solution as the shrinking solution can achieve microsphere shrinkage, thereby creating wrinkles on the surface structure.

[0112] Preferably, in the above preparation method, the mass ratio of the shrinkage liquid to the first microsphere is greater than 20:1. The mass of the shrinkage liquid relative to the first microsphere is sufficient to ensure that the first microsphere shrinks sufficiently. The specific amount of shrinkage liquid required depends on the type and amount of the first polymer. Preferably, in the above preparation method, the specific process of wrinkling in step S4 is as follows: the second microsphere is placed in the shrinkage liquid and stirred at a stirring rate of 300-1000 rpm for 6-18 hours. The liquid is then separated to obtain the surface-wrinkled microsphere adsorbent of the present invention. This wrinkling step is essential for the formation of wrinkles. To generate the wrinkled adsorbent, the surface area of ​​the microsphere (i.e., the first microsphere) must first be increased. Then, a rigid nanoparticle layer (i.e., the layer containing the second polymer) is coated on the surface of the microsphere. The second microsphere is then placed in the shrinkage liquid to shrink. After shrinkage, the rigid nanoparticle layer will form wrinkles on the surface of the microsphere. This wrinkling is achieved by utilizing the difference in swelling properties between the rigid metal nanoparticle layer and the elastic microsphere (i.e., the first microsphere), which is an essential condition for the formation of wrinkles.

[0113] Preferably, in the above preparation method, after wrinkling in step S4, the process further includes removing liquid, washing, and / or drying. The method of removing liquid is conventional in the art, such as centrifugation or filtration, and is not strictly limited. The washing solution can be a conventional organic or inorganic solvent in the art, such as water, ethanol, or xylene. The washing can be performed two, three, four, or more times to remove unreacted crosslinking agents or other excess substances. Additionally, the microspheres can be dried after washing for long-term preservation. The drying method is also commonly used in the art, such as baking, air drying, or freeze drying, to remove the liquid contained therein.

[0114] In this invention, the first microsphere continuously adsorbs and modifies the polymer, forming a wrinkled structure on the surface of the microsphere, thus obtaining a surface-wrinkled microsphere adsorbent. Clearly, the preparation method of this invention is simple and easy to implement, does not require stringent experimental conditions, and can be applied on a large scale.

[0115] In a second aspect of the invention, a highly biocompatible surface-wrinkled microsphere adsorbent is also provided, the adsorbent being prepared by the above method and comprising a core microsphere and a polymer layer.

[0116] Preferably, the highly biocompatible surface-wrinkled microsphere adsorbent of the present invention has a particle size of 200-400 μm. Microspheres in this size range can prolong the residence time of drugs in the gastrointestinal tract and improve the adsorption efficiency of drugs. At the same time, it helps to reduce the metabolism and degradation of drugs in the gastrointestinal tract and improve the bioavailability of drugs.

[0117] In addition, when the highly biocompatible surface-wrinkled microsphere adsorbent is used in other fields such as water purification, the particle size can be adjusted according to specific needs.

[0118] Preferably, the polymer layer of the highly biocompatible surface-wrinkled microsphere adsorbent of the present invention has one or more layers, and the polymers in each layer can be different or identical at intervals. In other words, when the polymer layer has 6 polymer layers, the polymers in each layer are different; or the first and third layers are the same, and the polymers in the remaining layers are different; or the polymers in the first, third, and fifth layers are the same, and the polymers in the other layers are different; or the polymers in the second, fourth, and sixth layers are the same, and the polymers in the other layers are different; or the polymers in the second, fourth, and sixth layers are the same, and the polymers in the first, third, and fifth layers are the same; or the polymers in the first, third, and fifth layers are the same, the polymers in the second and fourth layers are the same, and the polymer in the sixth layer is different from the polymers in the other layers, and so on.

[0119] The surface-wrinkled microsphere adsorbent provided by this invention has the characteristics of good biocompatibility and good adsorption capacity. It can reduce the accumulation of phosphate in the body by binding with phosphate ions in the gastrointestinal tract.

[0120] In a third aspect of the invention, an application of a highly biocompatible surface-wrinkled microsphere adsorbent is also provided, the application being in the pharmaceutical field.

[0121] In further detail, the specific applications are as follows: the highly biocompatible surface-wrinkled microsphere adsorbent is used as a phosphate binder to treat hyperphosphatemia, or to prepare drugs for treating hyperphosphatemia, or to prepare sustained-release formulations, or to prepare weight-loss drugs and / or health products, or to prepare drugs and / or health products for weight control, or to prepare drugs and / or health products for lowering blood lipids, or to prepare drugs and / or health products for protecting blood vessels, or to prepare gastrointestinal mucosal protectants, or to prepare drugs and / or health products for regulating intestinal flora.

[0122] When the highly biocompatible surface-wrinkled microsphere adsorbent is used as a phosphate binder to treat hyperphosphatemia, the outermost polymer of the highly biocompatible surface-wrinkled microsphere adsorbent is a cationic polymer, which forms a chelate with phosphate ions to inhibit phosphorus absorption in the gastrointestinal tract, thus treating hyperphosphatemia. Numerous experiments have demonstrated that when the highly biocompatible surface-wrinkled microsphere adsorbent of the present invention is used as a phosphate binder, the phosphorus adsorption capacity of microsphere adsorbents with anionic polymer outermost layers is far less than that of microsphere adsorbents with cationic polymer outermost layers. Furthermore, the highly biocompatible surface-wrinkled microsphere adsorbent also has cardiovascular protective effects such as lowering blood lipids and reducing vascular calcification, and can even be used as a carrier for other drugs to achieve sustained-release effects in the body.

[0123] Preferably, in the application described, the highly biocompatible surface-wrinkled microsphere adsorbent of the present invention has a particle size of 200-400 μm. Microspheres in this size range can prolong the residence time of drugs in the gastrointestinal tract and improve the adsorption efficiency of drugs. At the same time, they help reduce the metabolism and degradation of drugs in the gastrointestinal tract and improve the bioavailability of drugs.

[0124] Furthermore, when the highly biocompatible surface-wrinkled microsphere adsorbent of the present invention is used as a phosphorus binder, the surface of the first microsphere needs to be coated with multiple layers of polymer and wrinkled during the preparation process. These multiple polymer layers consist of two or more polymers. This is because numerous experiments have demonstrated that when the surface of the first microsphere is coated with only one layer of a second polymer, the resulting highly biocompatible surface-wrinkled microsphere adsorbent cannot adsorb large amounts of phosphorus and is therefore unsuitable for treating hyperphosphatemia.

[0125] When the highly biocompatible surface-wrinkled microsphere adsorbent of the present invention is used as a phosphate binder to treat hyperphosphatemia, it forms a chelate with phosphate to inhibit the absorption of phosphorus in the gastrointestinal tract and its excretion through feces, thereby reducing the accumulation of phosphorus in the body. At the same time, it can also reduce vascular calcification, increase gastrointestinal retention time, and prevent and treat cardiovascular complications caused by hyperphosphatemia.

[0126] The highly biocompatible surface-wrinkled microsphere adsorbent of this invention has been proven feasible as a phosphate binder for the treatment of hyperphosphatemia through numerous experiments. It can be administered alone or in combination with other drugs to form a drug composition for combined administration.

[0127] Compared with the prior art, the present invention has the following beneficial effects:

[0128] (1) Existing phosphorus binders often have complex preparation processes, while the preparation process of the highly biocompatible surface wrinkled microsphere adsorbent of the present invention is simple, the conditions are mild, and the raw materials are abundant, providing the necessary conditions for large-scale preparation.

[0129] (2) The highly biocompatible surface-wrinkled microsphere adsorbent of this invention exhibits excellent phosphate binding capacity and can effectively reduce serum phosphorus concentration in vivo. Furthermore, by increasing beneficial intestinal flora and reducing harmful intestinal flora, it regulates intestinal flora, significantly improves vascular calcification, and overcomes the shortcomings of traditional tablets such as high dosage, large tablet size, poor taste, and significant gastrointestinal side effects such as bloating, nausea, vomiting, and constipation.

[0130] (3) The highly biocompatible surface-wrinkled microsphere adsorbent of the present invention has good gastrointestinal stability and compatibility, and can maintain its adsorption performance for a long time under simulated gastric and intestinal fluid conditions. Its principle is consistent with the physiological mode of food digestion in the gastrointestinal tract, and its adsorption capacity has almost no obvious degradation or loss. It overcomes the problem that conventional phosphorus binders have limited residence time in the intestine and it is difficult to fully adsorb excess phosphorus in the intestine.

[0131] (4) The highly biocompatible surface-wrinkled microsphere adsorbent of the present invention has no cytotoxicity and good biocompatibility over a wide concentration range, and does not have safety issues such as hypercalcemia, negative effects on other drugs, or accumulation of metal elements in organs. Attached Figure Description

[0132] Figure 1 This is a schematic diagram of the droplet microfluidic technology used to prepare the first microsphere in this invention.

[0133] Figure 2 This is an optical microscope image of the first microsphere prepared in Example 2 of the present invention;

[0134] Figure 3 This is an optical microscope image and particle size distribution diagram (average particle size is 14.2 nm) of the silver nanoparticles in the first surface modification liquid prepared in Example 2 of the present invention.

[0135] Figure 4 This is a schematic diagram of the wrinkling process in step S4 of the preparation method of the present invention;

[0136] Figure 5 This is a morphological characterization diagram of product A8 from preparation example 8 of the present invention;

[0137] Figure 6 This is a morphological characterization diagram of product B2 prepared in Comparative Example 2 of the present invention;

[0138] Figure 7 This is the dynamic change curve of phosphorus adsorption obtained in Example 2 of the performance test of the present invention;

[0139] Figure 8 These are the cytotoxicity test results obtained in Example 3 of the performance test of this invention;

[0140] Figure 9 The product prepared in Example 5 of this invention is used to treat calcification of the thoracic aortic ring in rats with chronic kidney disease and hyperphosphatemia.

[0141] Figure 10 This is a quantitative analysis of the calcification area of ​​the thoracic aortic ring in rats with chronic kidney disease complicated by hyperphosphatemia treated with the product prepared in Example 5 of this invention.

[0142] Figure 11 The in vivo and in vitro imaging of the product prepared in Example 5 of this invention and the product prepared in Comparative Example 1 characterize the gastrointestinal retention time.

[0143] Figure 12 This is a schematic diagram of the highly biocompatible surface-wrinkled microsphere adsorbent of the present invention used for phosphorus adsorption.

[0144] Among them, Figure 1 In the diagram, 1 is the dispersed phase inlet, 2 is the continuous phase inlet, and 3 is the collection phase inlet. Detailed Implementation

[0145] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0146] All raw materials used in the following examples are commercially available, and all water used is deionized water. Furthermore, the process flow diagram for preparing the first microspheres using microfluidic technology is as follows: Figure 1The microchannels of the droplet microfluidic device are configured such that 1 is the dispersed phase inlet, 2 is the continuous phase inlet, and 3 is the collection phase inlet. The dispersed and continuous phases are injected into the microchannels through inlet 1 and inlet 2, respectively, while the collection phase is injected through inlet 3. Microdroplets form at the intersection of the dispersed and continuous phases and flow into the collection phase. After solidification, liquid removal, and washing, the first microspheres are obtained. Preferably, the first microspheres are prepared using the first polymer solution via droplet microfluidic technology because this method allows for better control of the microsphere size and uniformity, and results in excellent dispersibility. In particular, chitosan microspheres prepared using chitosan solution via droplet microfluidic technology exhibit excellent strength and pH response behavior; they expand in acidic solutions and shrink in alkaline solutions. This pH-responsive characteristic allows the microspheres to rapidly respond to environmental changes and interact with other components under given conditions.

[0147] In addition, the first microspheres, second microspheres and final products prepared in the following examples were not dried unless explicitly stated otherwise. This is because the following examples do not involve operations such as storage, transportation, and commercialization that lead to the market and reach specific users. However, in practical applications, drying is necessary depending on the specific circumstances for better commercialization.

[0148] Preparation Examples

[0149] Preparation Example 1

[0150] S1 Preparation of the first microspheres

[0151] Preparation of the first polymer solution: Dissolve polylactic acid-glycolic acid copolymer (PLGA) in dichloromethane organic solvent and mix evenly to obtain the first polymer solution, wherein the mass fraction of polylactic acid-glycolic acid copolymer in the first polymer solution is 10%;

[0152] Preparation of continuous phase: Polyvinyl alcohol (PVA) is mixed with water to obtain a 10% (w / w) aqueous solution of polyvinyl alcohol. Polyethylene glycol (PEG) is mixed with water to obtain a 10% (w / w) aqueous solution of polyethylene glycol. Then, the aqueous solutions of polyvinyl alcohol and polyethylene glycol are mixed at a volume ratio of 3:2 to obtain a continuous phase.

[0153] Emulsion polymerization was carried out: 100 mL of the first polymer solution was added dropwise to 200 mL of continuous phase at 600 rpm and stirred continuously for 12 h. After centrifugation, the supernatant was removed and a white precipitate was obtained. The white precipitate was washed three times with deionized water and dried to obtain PLGA microspheres, which were the first microspheres with a particle size of 450 μm.

[0154] S2 is used to prepare surface modification liquid.

[0155] Preparation of silver nitrate aqueous solution: Mix silver nitrate and water evenly to obtain a silver nitrate aqueous solution with a mass fraction of 0.2%;

[0156] Preparation of sodium borohydride aqueous solution: Mix sodium borohydride with water until homogeneous to obtain a sodium borohydride aqueous solution with a mass fraction of 1%;

[0157] Preparation of the first surface modification solution: Sodium alginate and water are mixed evenly to obtain a sodium alginate aqueous solution with a mass fraction of 0.5%. Silver nitrate aqueous solution is added at a volume ratio of sodium alginate aqueous solution to silver nitrate aqueous solution of 10:1. After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of silver nitrate aqueous solution to sodium borohydride aqueous solution of 2:1 under stirring to carry out a reduction reaction and obtain the first surface modification solution.

[0158] Preparation of the second surface modification solution: Aminated cellulose and water are mixed evenly to obtain an aqueous solution of aminated cellulose with a mass fraction of 0.5%. Silver nitrate aqueous solution is added at a volume ratio of 10:1 to 10:1. After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 to 10:1 under stirring to carry out a reduction reaction and obtain the second surface modification solution.

[0159] S3 Preparation of the Second Microsphere

[0160] 1 g of the first microspheres was soaked in 25 mL of water to allow them to fully swell. The swelling equilibrium was observed under a microscope. Then, the swelled microspheres were added to 25 mL of the first surface modification solution and shaken on a shaker at room temperature for 2 hours. The mixture was then allowed to stand, and the supernatant was removed. The microspheres were then washed three times with water. Next, the first microspheres coated with sodium alginate were added to 25 mL of the second surface modification solution and shaken on a shaker at room temperature for 2 hours. The mixture was then allowed to stand, and the supernatant was removed. The microspheres were then washed three times with water. The process of coating with sodium alginate and aminoated cellulose was repeated 10 times each. Finally, the product, the second microspheres, was collected by centrifugation.

[0161] S4 Preparation of Surface-Wrinkled Microsphere Adsorbents

[0162] The collected second microspheres were placed in 25 mL of anhydrous ethanol and allowed to shrink completely. The mixture was stirred at 500 rpm for 12 hours, centrifuged to collect the microspheres, and then dried to obtain the surface-wrinkled microsphere adsorbent. The final product was denoted as A1.

[0163] Preparation Example 2

[0164] S1 Preparation of the first microspheres

[0165] Preparation of the first polymer solution: Chitosan is dissolved in deionized water and mixed evenly to obtain the first polymer solution, wherein the mass fraction of chitosan in the first polymer solution is 1.5%;

[0166] Preparation of continuous phase: Span 80 and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8% and the remainder is n-octane;

[0167] Preparation of the collection phase: Span 80, glutaraldehyde and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8%, the mass fraction of glutaraldehyde is 1%, and the remainder is n-octane;

[0168] Implementing droplet microfluidics: 100 mL of the obtained first polymer solution and the dispersed phase were introduced into a fluid-focusing cross-shaped microfluidic channel for shearing. The flow rate of the first polymer solution was 2 mL / h, and the flow rate of the dispersed phase was 100 mL / h, forming chitosan microdroplets. These microdroplets were then cross-linked and solidified in the collected phase. Subsequently, the liquid was removed by centrifugation. The microspheres were then washed with 100%, 95%, and 75% ethanol aqueous solutions and deionized water, respectively. After drying, chitosan microspheres, i.e., the first microspheres, were obtained. The microfluidic chip was fluid-focusing type, with a microchannel diameter of 200 μm and a flow rate ratio of dispersed phase to continuous phase of 1:50.

[0169] S2 is used to prepare surface modification liquid.

[0170] Preparation of silver nitrate aqueous solution: Mix silver nitrate and water evenly to obtain a silver nitrate aqueous solution with a mass fraction of 0.2%;

[0171] Preparation of sodium borohydride aqueous solution: Mix sodium borohydride with water until homogeneous to obtain a sodium borohydride aqueous solution with a mass fraction of 1%;

[0172] Preparation of the first surface modification solution: Polyacrylic acid and water were mixed evenly to obtain a 4% (w / w) polyacrylic acid aqueous solution. Silver nitrate aqueous solution was added at a volume ratio of 10:1 (polyacrylic acid aqueous solution to silver nitrate aqueous solution). After mixing evenly, sodium borohydride aqueous solution was added at a volume ratio of 2:1 (silver nitrate aqueous solution to sodium borohydride aqueous solution) under stirring to carry out a reduction reaction, thus obtaining the first surface modification solution. The optical microscope image and particle size distribution diagram of the silver nanoparticles in the first surface modification solution are shown below. Figure 3 ;

[0173] Preparation of the second surface modification solution: Polyethyleneimine and water are mixed evenly to obtain a 4% (w / w) polyethyleneimine aqueous solution. Silver nitrate aqueous solution is added at a volume ratio of 10:1 (polyethyleneimine aqueous solution to silver nitrate aqueous solution). After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 (silver nitrate aqueous solution to sodium borohydride aqueous solution) under stirring to carry out a reduction reaction, thereby obtaining the second surface modification solution.

[0174] S3 Preparation of the Second Microsphere

[0175] 1g of the first microspheres was soaked in 25mL of water to allow them to swell fully. The swelling equilibrium was observed under a microscope. The first microspheres that had reached swelling equilibrium were then added to 25mL of the first surface modification solution and shaken on a shaker at room temperature for 2 hours. Then, 25mL of the second surface modification solution was added and shaken on a shaker at room temperature for 2 hours. The mixture was then allowed to stand and the supernatant was removed. The microspheres were then washed three times with water and finally collected by centrifugation.

[0176] S4 Preparation of Surface-Wrinkled Microsphere Adsorbents

[0177] The collected second microspheres were placed in 25 mL of 5.71% sodium hydroxide solution (1.5 mol / L) and allowed to shrink completely. The mixture was stirred at 500 rpm for 12 hours, and the microspheres were collected by centrifugation. The microspheres were then washed three times with 10 mL of deionized water and dried to obtain the surface-wrinkled microsphere adsorbent. The final product was denoted as A2.

[0178] Preparation Example 3

[0179] S1 Preparation of the first microspheres

[0180] Preparation of the first polymer solution: Sodium alginate is dissolved in deionized water and mixed evenly to obtain the first polymer solution, wherein the mass fraction of sodium alginate in the first polymer solution is 1.5%;

[0181] Preparation of continuous phase: Span 80 and paraffin oil are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8% and the remainder is paraffin oil;

[0182] Preparation of the collecting phase: Span 80 and calcium chloride are mixed evenly with paraffin oil to obtain the collecting phase, wherein the mass fraction of Span is 8%, the mass fraction of calcium chloride is 1%, and the remainder is paraffin oil;

[0183] Implementing droplet microfluidic technology: 200 mL of the obtained first polymer solution and the continuous phase solution were introduced into a fluid-focusing cross-shaped microfluidic channel for shearing. The flow rate of the first polymer solution was 1.5 mL / h, and the flow rate of the dispersed phase was 150 mL / h, forming sodium alginate microdroplets. These microdroplets were then cross-linked and solidified in the collected phase. Subsequently, the liquid was removed by centrifugation. The microspheres were then washed with 100%, 95%, and 75% ethanol aqueous solutions and deionized water, respectively. After drying, sodium alginate microspheres, i.e., the first microspheres, were obtained. The microfluidic chip was fluid-focusing type, with a microchannel diameter of 200 μm, and the flow rate ratio of the first polymer solution to the continuous phase was 1:100.

[0184] S2 is used to prepare surface modification liquid.

[0185] Preparation of silver nitrate aqueous solution: Mix silver nitrate and water evenly to obtain a silver nitrate aqueous solution with a mass fraction of 0.2%;

[0186] Preparation of sodium borohydride aqueous solution: Mix sodium borohydride with water until homogeneous to obtain a sodium borohydride aqueous solution with a mass fraction of 1%;

[0187] Preparation of the first surface modification solution: Polyacrylic acid and water are mixed evenly to obtain a 2% (w / w) polyacrylic acid aqueous solution. Silver nitrate aqueous solution is added at a volume ratio of 10:1 (polyacrylic acid aqueous solution to silver nitrate aqueous solution). After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 (silver nitrate aqueous solution to sodium borohydride aqueous solution) under stirring to carry out a reduction reaction and obtain the first surface modification solution.

[0188] Preparation of the second surface modification solution: Polyethyleneimine and water are mixed evenly to obtain a 2% (w / w) polyethyleneimine aqueous solution. Silver nitrate aqueous solution is added at a volume ratio of 10:1 (polyethyleneimine aqueous solution to silver nitrate aqueous solution). After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 (silver nitrate aqueous solution to sodium borohydride aqueous solution) under stirring to carry out a reduction reaction, thereby obtaining the second surface modification solution.

[0189] S3 Preparation of the Second Microsphere

[0190] Soak 1g of the first microsphere in 25mL of water to allow it to swell fully. Observe under a microscope whether swelling equilibrium has been reached. Then, add the first microsphere, which has reached swelling equilibrium, to 25mL of the first surface modification solution and shake on a shaker at room temperature for 2 hours. Then add 25mL of the second surface modification solution and shake on a shaker at room temperature for 2 hours. Then let it stand and remove the supernatant. After washing with water three times, finally centrifuge to collect the product, which is the second microsphere.

[0191] S4 Preparation of Surface-Wrinkled Microsphere Adsorbents

[0192] The collected second microspheres were placed in 25 mL of anhydrous ethanol and allowed to shrink completely. The mixture was stirred at 500 rpm for 12 hours, centrifuged to collect the microspheres, and then dried to obtain the surface-wrinkled microsphere adsorbent. The final product was denoted as A3.

[0193] Preparation Example 4

[0194] S1 Preparation of the first microspheres

[0195] Preparation of the first polymer solution: Dissolve hyaluronic acid in water and mix thoroughly to obtain the first polymer solution, wherein the mass fraction of hyaluronic acid in the first polymer solution is 0.5%;

[0196] Preparation of crosslinking solution: Mix mercaptoethanol and sodium hydroxide with water to obtain a crosslinking solution, wherein the mass fraction of mercaptoethanol in the crosslinking solution is 1%, the mass fraction of sodium hydroxide is 0.1%, and the remainder is deionized water;

[0197] Spraying to form microspheres: 200 mL of the first polymer solution was placed in a spraying device with an inlet temperature of 200°C and an outlet temperature of 30°C. The atomizer speed was 10000 rpm. The first polymer solution was sprayed into a mist droplet through the nozzle and 2000 mL was sprayed into the crosslinking solution. The droplet was then cured and crosslinked in the crosslinking solution for 1 hour. Finally, 2000 mL of deionized water was added for dilution to terminate the crosslinking reaction. After filtration and drying, the crosslinked hyaluronic acid microspheres, i.e., the first microspheres, were obtained.

[0198] S2 is used to prepare surface modification liquid.

[0199] Preparation of silver nitrate aqueous solution: Mix silver nitrate and water evenly to obtain a silver nitrate aqueous solution with a mass fraction of 0.2%;

[0200] Preparation of sodium borohydride aqueous solution: Mix sodium borohydride with water until homogeneous to obtain a sodium borohydride aqueous solution with a mass fraction of 1%;

[0201] Preparation of the first surface modification solution: Sodium alginate and water are mixed evenly to obtain a sodium alginate aqueous solution with a mass fraction of 2%. Silver nitrate aqueous solution is added at a volume ratio of sodium alginate aqueous solution to silver nitrate aqueous solution of 10:1. After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of silver nitrate aqueous solution to sodium borohydride aqueous solution of 2:1 under stirring to carry out a reduction reaction and obtain the first surface modification solution.

[0202] Preparation of the second surface modification solution: Aminated cellulose and water are mixed evenly to obtain an aqueous solution of aminated cellulose with a mass fraction of 2%. Silver nitrate aqueous solution is added at a volume ratio of 10:1 to 10:1. After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 to 10:1 under stirring to carry out a reduction reaction and obtain the second surface modification solution.

[0203] S3 Preparation of the Second Microsphere

[0204] 1g of the first microspheres was soaked in 30mL of water to allow them to swell fully. The swelling equilibrium was observed under a microscope. Then, the first microspheres, after reaching swelling equilibrium, were added to 25mL of the first surface-modifying solution. The solution was shaken on a 25mL shaker at room temperature for 2 hours, then allowed to stand and the supernatant was removed. The microspheres were then washed three times with water. Next, the first microspheres coated with sodium alginate were added to 25mL of the second surface-modifying cellulose solution. The solution was shaken on a shaker at room temperature for 2 hours, then allowed to stand and the supernatant was removed. The microspheres were then washed three times with water. The above processes of coating with sodium alginate and aminated cellulose were repeated 10 times each. Finally, the product, the second microspheres, was collected by centrifugation.

[0205] S4 Preparation of Surface-Wrinkled Microsphere Adsorbents

[0206] The collected second microspheres were placed in 25 mL of anhydrous ethanol and allowed to shrink completely. The mixture was stirred at 500 rpm for 12 hours, centrifuged to collect the microspheres, and then dried to obtain the surface-wrinkled microsphere adsorbent. The final product was denoted as A4.

[0207] Preparation Example 5

[0208] S1 Preparation of the first microspheres

[0209] Preparation of the first polymer solution: Chitosan is dissolved in deionized water and mixed evenly to obtain the first polymer solution, wherein the mass fraction of chitosan in the first polymer solution is 1%;

[0210] Preparation of continuous phase: Span 80 and glutaraldehyde are mixed evenly with n-octane to obtain a continuous phase, wherein the mass fraction of span is 8%, the mass fraction of glutaraldehyde is 1%, and the remainder is n-octane;

[0211] Emulsion polymerization was carried out: 100 mL of the first polymer solution was added dropwise to 1000 mL of continuous phase at 800 rpm and stirred continuously for 2 h. After centrifugation, the supernatant was removed and a white precipitate was obtained. The microspheres were then washed with 100%, 95%, and 75% ethanol aqueous solution and deionized water, respectively. After drying, chitosan microspheres were obtained, which were the first microspheres.

[0212] S2 is used to prepare surface modification liquid.

[0213] Preparation of silver nitrate aqueous solution: Mix silver nitrate and water evenly to obtain a silver nitrate aqueous solution with a mass fraction of 0.2%;

[0214] Preparation of sodium borohydride aqueous solution: Mix sodium borohydride with water until homogeneous to obtain a sodium borohydride aqueous solution with a mass fraction of 1%;

[0215] Preparation of the first surface modification solution: Sodium alginate and water are mixed evenly to obtain a sodium alginate aqueous solution with a mass fraction of 4%. Silver nitrate aqueous solution is added at a volume ratio of sodium alginate aqueous solution to silver nitrate aqueous solution of 10:1. After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of silver nitrate aqueous solution to sodium borohydride aqueous solution of 2:1 under stirring to carry out a reduction reaction and obtain the first surface modification solution.

[0216] Preparation of the second surface modification solution: Aminated cellulose and water are mixed evenly to obtain an aqueous solution of aminated cellulose with a mass fraction of 4%. Silver nitrate aqueous solution is added at a volume ratio of 10:1 to 10:1. After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 to 10:1 under stirring to carry out a reduction reaction and obtain the second surface modification solution.

[0217] S3 Preparation of the Second Microsphere

[0218] 1 g of the first microspheres was soaked in 25 mL of 5.47% hydrochloric acid (1.5 mol / L) to allow them to fully swell. The swelling equilibrium was observed under a microscope. Then, the first microspheres, after reaching swelling equilibrium, were added to 25 mL of the first surface modification solution and shaken on a shaker at room temperature for 2 hours. The mixture was then allowed to stand, and the supernatant was removed. The microspheres were then washed three times with water. Next, the first microspheres coated with sodium alginate were added to 25 mL of the second surface modification solution and shaken on a shaker at room temperature for 2 hours. The mixture was then allowed to stand, and the supernatant was removed. The microspheres were then washed three times with water. The process of coating with sodium alginate and aminoated cellulose was repeated seven times each. Finally, the product, the second microspheres, was collected by centrifugation.

[0219] S4 Preparation of Surface-Wrinkled Microsphere Adsorbents

[0220] The collected second microspheres were placed in 25 mL of 5.71% sodium hydroxide solution (1.5 mol / L) to shrink completely, stirred at 500 rpm for 12 hours, centrifuged to collect the microspheres, and then washed three times with 10 mL of deionized water and dried to obtain the surface-wrinkled microsphere adsorbent. The final product is denoted as A5.

[0221] Preparation Example 6

[0222] S1 Preparation of the first microspheres

[0223] Preparation of the first polymer solution: Sodium alginate is dissolved in water and mixed evenly to obtain the first polymer solution, wherein the mass fraction of sodium alginate in the first polymer solution is 1.5%;

[0224] Preparation of crosslinking solution: Mix calcium chloride and water evenly to obtain a crosslinking solution, wherein the mass fraction of calcium chloride in the crosslinking solution is 1%, and the remainder is deionized water;

[0225] Spraying to form microspheres: 100 mL of the first polymer solution was placed in a spraying device with an inlet temperature of 150°C and an outlet temperature of 35°C. The atomizer speed was 15000 rpm. The first polymer solution was sprayed into a mist droplet through the nozzle and 1000 mL was sprayed into the crosslinking solution. The droplet was then cured and crosslinked in the crosslinking solution for 4 hours. Finally, 2000 mL of deionized water was added for dilution to terminate the crosslinking reaction. After filtration and drying, the crosslinked sodium alginate microspheres, i.e., the first microspheres, were obtained.

[0226] S2 is used to prepare surface modification liquid.

[0227] Preparation of silver nitrate aqueous solution: Mix silver nitrate and water evenly to obtain a silver nitrate aqueous solution with a mass fraction of 0.2%;

[0228] Preparation of sodium borohydride aqueous solution: Mix sodium borohydride with water until homogeneous to obtain a sodium borohydride aqueous solution with a mass fraction of 1%;

[0229] Preparation of the first surface modification solution: Polyethyleneimine and water are mixed evenly to obtain a 2% (w / w) polyethyleneimine aqueous solution. Silver nitrate aqueous solution is added at a volume ratio of 10:1 (polyethyleneimine aqueous solution to silver nitrate aqueous solution). After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 (silver nitrate aqueous solution to sodium borohydride aqueous solution) under stirring to carry out a reduction reaction, thereby obtaining the second surface modification solution.

[0230] Preparation of the second surface modification solution: Polyacrylic acid and water are mixed evenly to obtain a 2% (w / w) polyacrylic acid aqueous solution. Silver nitrate aqueous solution is added at a volume ratio of 10:1 (polyacrylic acid aqueous solution to silver nitrate aqueous solution). After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 (silver nitrate aqueous solution to sodium borohydride aqueous solution) under stirring to carry out a reduction reaction, thereby obtaining the first surface modification solution.

[0231] S3 Preparation of the Second Microsphere

[0232] 1g of the first microspheres was soaked in 25mL of water to allow them to swell fully. The swelling equilibrium was observed under a microscope. The first microspheres that had reached swelling equilibrium were then added to 25mL of the first surface modification solution and shaken on a shaker at room temperature for 2 hours. Then, 25mL of the second surface modification solution was added and shaken on a shaker at room temperature for 2 hours. The mixture was then allowed to stand and the supernatant was removed. The mixture was then washed with water three times. The process of coating polyethyleneimine and polyacrylic acid was repeated seven times each. Finally, the product, namely the second microspheres, was collected by centrifugation.

[0233] S4 Preparation of Surface-Wrinkled Microsphere Adsorbents

[0234] The collected second microspheres were placed in 25 mL of methanol and allowed to shrink completely. The mixture was stirred at 500 rpm for 12 hours, centrifuged to collect the microspheres, and then dried to obtain the surface-wrinkled microsphere adsorbent. The final product was denoted as A6.

[0235] Preparation Example 7

[0236] S1 Preparation of the first microspheres

[0237] Preparation of the first polymer solution: Dissolve hyaluronic acid in water and mix thoroughly to obtain the first polymer solution, wherein the mass fraction of hyaluronic acid in the first polymer solution is 0.5%;

[0238] Preparation of continuous phase: Tween 60 and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Tween 60 is 5% and the remainder is n-octane;

[0239] Preparation of the collecting phase: Tween 60, mercaptoethanol, and sodium hydroxide are mixed evenly with n-octane to obtain the collecting phase, wherein the mass fraction of Tween 60 is 5%, the mass fraction of mercaptoethanol is 1%, the mass fraction of sodium hydroxide is 0.1%, and the remainder is n-octane;

[0240] Implement droplet microfluidics: 200 mL of the obtained first polymer solution and the continuous phase solution were introduced into a fluid-focusing cross-shaped microfluidic channel for shearing. The flow rate of the first polymer solution was 3 mL / h, and the flow rate of the dispersed phase was 150 mL / h, forming microdroplets. The microdroplets were then cross-linked and solidified in the collected phase. The liquid was then removed by centrifugation. The product was then washed with 100%, 95%, and 75% ethanol aqueous solutions and deionized water, respectively. After drying, hyaluronic acid microspheres, i.e., the first microspheres, were obtained. The microfluidic chip was fluid-focusing type, with a microchannel diameter of 200 μm and a flow rate ratio of 1:50 between the microchannel chip and the continuous phase of the first polymer solution.

[0241] S2 is used to prepare surface modification liquid.

[0242] Preparation of silver nitrate aqueous solution: Mix silver nitrate and water evenly to obtain a silver nitrate aqueous solution with a mass fraction of 0.2%;

[0243] Preparation of sodium borohydride aqueous solution: Mix sodium borohydride with water until homogeneous to obtain a sodium borohydride aqueous solution with a mass fraction of 1%;

[0244] Preparation of the first surface modification solution: Polyacrylic acid and water are mixed evenly to obtain a 4% (w / w) polyacrylic acid aqueous solution. Silver nitrate aqueous solution is added at a volume ratio of 10:1 (polyacrylic acid aqueous solution to silver nitrate aqueous solution). After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 (silver nitrate aqueous solution to sodium borohydride aqueous solution) under stirring to carry out a reduction reaction and obtain the first surface modification solution.

[0245] Preparation of the second surface modification solution: Polyethyleneimine and water are mixed evenly to obtain a 4% (w / w) polyethyleneimine aqueous solution. Silver nitrate aqueous solution is added at a volume ratio of 10:1 (polyethyleneimine aqueous solution to silver nitrate aqueous solution). After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 (silver nitrate aqueous solution to sodium borohydride aqueous solution) under stirring to carry out a reduction reaction, thereby obtaining the second surface modification solution.

[0246] S3 Preparation of the Second Microsphere

[0247] Soak 1g of the first microsphere in 25mL of water to allow it to swell fully. Observe under a microscope whether swelling equilibrium has been reached. Then, add the first microsphere, which has reached swelling equilibrium, to 25mL of the first surface modification solution and shake on a shaker at room temperature for 2 hours. Then add 25mL of the second surface modification solution and shake on a shaker at room temperature for 2 hours. Then let it stand and remove the supernatant. After washing with water three times, finally centrifuge to collect the product, which is the second microsphere.

[0248] S4 Preparation of Surface-Wrinkled Microsphere Adsorbents

[0249] The collected second microspheres were placed in 25 mL of anhydrous ethanol and allowed to shrink completely. The mixture was stirred at 500 rpm for 12 hours, centrifuged to collect the microspheres, and then dried to obtain the surface-wrinkled microsphere adsorbent. The final product was denoted as A7.

[0250] Preparation Example 8

[0251] S1 Preparation of the first microspheres

[0252] Preparation of the first polymer solution: Chitosan is dissolved in water and mixed evenly to obtain the first polymer solution, wherein the mass fraction of chitosan in the first polymer solution is 1%;

[0253] Preparation of crosslinking solution: Mix glutaraldehyde and n-octane evenly to obtain a crosslinking solution, wherein the mass fraction of glutaraldehyde in the crosslinking solution is 1%, and the remainder is n-octane;

[0254] Spraying to form microspheres: 100 mL of the first polymer solution was placed in a spraying device with an inlet temperature of 100°C and an outlet temperature of 25°C. The atomizer speed was 18000 rpm. The first polymer solution was sprayed into a mist droplet through the nozzle and sprayed into 1000 mL of crosslinking solution. The droplet was then cured and crosslinked in the crosslinking solution for 2 hours. Finally, 2000 mL of deionized water was added for dilution to terminate the crosslinking reaction. The mixture was filtered and dried to obtain the crosslinked chitosan microspheres, i.e., the first microspheres.

[0255] S2 is used to prepare surface modification liquid.

[0256] Preparation of silver nitrate aqueous solution: Mix silver nitrate and water evenly to obtain a silver nitrate aqueous solution with a mass fraction of 0.2%;

[0257] Preparation of sodium borohydride aqueous solution: Mix sodium borohydride with water until homogeneous to obtain a sodium borohydride aqueous solution with a mass fraction of 1%;

[0258] Preparation of the first surface modification solution: Sodium alginate and water are mixed evenly to obtain a sodium alginate aqueous solution with a mass fraction of 0.5%. Silver nitrate aqueous solution is added at a volume ratio of sodium alginate aqueous solution to silver nitrate aqueous solution of 10:1. After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of silver nitrate aqueous solution to sodium borohydride aqueous solution of 2:1 under stirring to carry out a reduction reaction and obtain the first surface modification solution.

[0259] Preparation of the second surface modification solution: Aminated cellulose and water are mixed evenly to obtain an aqueous solution of aminated cellulose with a mass fraction of 0.5%. Silver nitrate aqueous solution is added at a volume ratio of 10:1 to 10:1. After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 to 10:1 under stirring to carry out a reduction reaction and obtain the second surface modification solution.

[0260] S3 Preparation of the Second Microsphere

[0261] 1 g of the first microspheres was soaked in 35 mL of 5.47% hydrochloric acid (1.5 mol / L) to allow them to fully swell. The swelling equilibrium was observed under a microscope. Then, the first microspheres that had reached swelling equilibrium were added to 25 mL of the first surface modification solution and shaken on a shaker at room temperature for 2 hours. Then, 25 mL of the second surface modification solution was added and shaken on a shaker at room temperature for 2 hours. The mixture was then allowed to stand and the supernatant was removed. The microspheres were then washed with water three times. The above process of coating sodium alginate and aminated cellulose was repeated eight times each. Finally, the product, namely the second microspheres, was collected by centrifugation.

[0262] S4 Preparation of Surface-Wrinkled Microsphere Adsorbents

[0263] The collected second microspheres were placed in 25 mL of 5.71% sodium hydroxide solution (1.5 mol / L) and allowed to shrink completely. The mixture was stirred at 500 rpm for 12 hours, and the microspheres were collected by centrifugation. The microspheres were then washed three times with 10 mL of deionized water and dried to obtain the surface-wrinkled microsphere adsorbent. The final product was denoted as A8.

[0264] Comparative Examples

[0265] Comparative Example 1

[0266] S1 Preparation of the first microspheres

[0267] Preparation of the first polymer solution: Chitosan is dissolved in deionized water and mixed evenly to obtain the first polymer solution, wherein the mass fraction of chitosan in the first polymer solution is 1.5%;

[0268] Preparation of continuous phase: Span 80 and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8% and the remainder is n-octane;

[0269] Preparation of the collection phase: Span 80, glutaraldehyde and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8%, the mass fraction of glutaraldehyde is 1%, and the remainder is n-octane;

[0270] Implementing droplet microfluidics: 100 mL of the obtained first polymer solution and the dispersed phase were introduced into a fluid-focusing cross-shaped microfluidic channel for shearing. The flow rate of the first polymer solution was 2 mL / h, and the flow rate of the dispersed phase was 100 mL / h, forming chitosan microdroplets. These microdroplets were then cross-linked and solidified in the collected phase. Subsequently, the liquid was removed by centrifugation. The microspheres were then washed with 100%, 95%, and 75% ethanol aqueous solutions and deionized water, respectively. After drying, chitosan microspheres, i.e., the first microspheres, were obtained. The microfluidic chip was fluid-focusing type, with a microchannel diameter of 200 μm and a flow rate ratio of dispersed phase to continuous phase of 1:50.

[0271] Comparative Example 2

[0272] S1 Preparation of the first microspheres

[0273] Preparation of the first polymer solution: Chitosan is dissolved in deionized water and mixed evenly to obtain the first polymer solution, wherein the mass fraction of chitosan in the first polymer solution is 1.5%;

[0274] Preparation of continuous phase: Span 80 and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8% and the remainder is n-octane;

[0275] Preparation of the collection phase: Span 80, glutaraldehyde and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8%, the mass fraction of glutaraldehyde is 1%, and the remainder is n-octane;

[0276] Implementing droplet microfluidics: 100 mL of the obtained first polymer solution and the dispersed phase were introduced into a fluid-focusing cross-shaped microfluidic channel for shearing. The flow rate of the first polymer solution was 2 mL / h, and the flow rate of the dispersed phase was 100 mL / h, forming chitosan microdroplets. These microdroplets were then cross-linked and solidified in the collected phase. Subsequently, the liquid was removed by centrifugation. The microspheres were then washed with 100%, 95%, and 75% ethanol aqueous solutions and deionized water, respectively. After drying, chitosan microspheres, i.e., the first microspheres, were obtained. The microfluidic chip was fluid-focusing type, with a microchannel diameter of 200 μm and a flow rate ratio of dispersed phase to continuous phase of 1:50.

[0277] S2 is used to prepare surface modification liquid.

[0278] Preparation of polyacrylic acid aqueous solution: Polyacrylic acid and water are mixed evenly to obtain a polyacrylic acid aqueous solution with a mass fraction of 4%;

[0279] Preparation of polyethyleneimine aqueous solution: Mix polyethyleneimine with water evenly to obtain a polyethyleneimine aqueous solution with a mass fraction of 4%.

[0280] S3 Preparation of the Second Microsphere

[0281] 1 g of the first microsphere was soaked in 45 mL of 5.47% hydrochloric acid (1.5 mol / L) to allow it to swell fully. The swelling equilibrium was observed under a microscope. After swelling equilibrium was reached, the first microsphere was added to 25 mL of polyacrylic acid solution and shaken on a shaker at room temperature for 2 hours. Then, it was added to 25 mL of polyethyleneimine solution and shaken on a shaker at room temperature for 2 hours. After standing, the supernatant was removed, and the microsphere was washed three times with water. Finally, the product, namely the second microsphere, was collected by centrifugation.

[0282] S4 Preparation of Surface-Wrinkled Microsphere Adsorbents

[0283] The collected second microspheres were placed in 25 mL of 5.71% sodium hydroxide solution (1.5 mol / L) and allowed to shrink completely. The mixture was stirred at 500 rpm for 12 hours, and the microspheres were collected by centrifugation. The microspheres were then washed three times with 10 mL of deionized water and dried to obtain assembled microspheres without silver nanoparticles. The final product was designated as B2.

[0284] Comparative Example 3

[0285] S1 Preparation of the first microspheres

[0286] Preparation of the first polymer solution: Chitosan is dissolved in deionized water and mixed evenly to obtain the first polymer solution, wherein the mass fraction of chitosan in the first polymer solution is 1.5%;

[0287] Preparation of continuous phase: Span 80 and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8% and the remainder is n-octane;

[0288] Preparation of the collection phase: Span 80, glutaraldehyde and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8%, the mass fraction of glutaraldehyde is 1%, and the remainder is n-octane;

[0289] Implementing droplet microfluidics: 100 mL of the obtained first polymer solution and the dispersed phase were introduced into a fluid-focusing cross-shaped microfluidic channel for shearing. The flow rate of the first polymer solution was 2 mL / h, and the flow rate of the dispersed phase was 100 mL / h, forming chitosan microdroplets. These microdroplets were then cross-linked and solidified in the collected phase. Subsequently, the liquid was removed by centrifugation. The microspheres were then washed with 100%, 95%, and 75% ethanol aqueous solutions and deionized water, respectively. After drying, chitosan microspheres, i.e., the first microspheres, were obtained. The microfluidic chip was fluid-focusing type, with a microchannel diameter of 200 μm and a flow rate ratio of dispersed phase to continuous phase of 1:50.

[0290] S2 is used to prepare surface modification liquid.

[0291] Preparation of silver nitrate aqueous solution: Mix silver nitrate and water evenly to obtain a silver nitrate aqueous solution with a mass fraction of 0.2%;

[0292] Preparation of sodium borohydride aqueous solution: Mix sodium borohydride with water until homogeneous to obtain a sodium borohydride aqueous solution with a mass fraction of 1%;

[0293] Preparation of the first surface modification solution: Polyacrylic acid and water are mixed evenly to obtain a 4% (w / w) polyacrylic acid aqueous solution. Silver nitrate aqueous solution is added at a volume ratio of 10:3 (polyacrylic acid aqueous solution to silver nitrate aqueous solution). After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 (silver nitrate aqueous solution to sodium borohydride aqueous solution) under stirring to carry out a reduction reaction and obtain the first surface modification solution.

[0294] Preparation of the second surface modification solution: Polyethyleneimine and water are mixed evenly to obtain a 4% (w / w) polyethyleneimine aqueous solution. Silver nitrate aqueous solution is added at a volume ratio of 10:5 (polyethyleneimine aqueous solution to silver nitrate aqueous solution). After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 (silver nitrate aqueous solution to sodium borohydride aqueous solution) under stirring to carry out a reduction reaction, thereby obtaining the second surface modification solution.

[0295] S3 Preparation of the Second Microsphere

[0296] 1 g of the first microsphere was soaked in 25 mL of 5.47% hydrochloric acid (1.5 mol / L) to allow it to swell fully. The swelling equilibrium was observed under a microscope. Then, the first microsphere, after reaching swelling equilibrium, was added to 25 mL of the first surface modification solution and shaken on a shaker at room temperature for 2 hours. Then, the second surface modification solution was added and shaken on a shaker at room temperature for 2 hours. After standing, the supernatant was removed, and the microsphere was washed three times with water. Finally, the product, namely the second microsphere, was collected by centrifugation.

[0297] S4 Preparation of Surface-Wrinkled Microsphere Adsorbents

[0298] The collected second microspheres were placed in 25 mL of 5.71% sodium hydroxide solution (1.5 mol / L) and allowed to shrink completely. The mixture was stirred at 500 rpm for 12 hours, and the microspheres were collected by centrifugation. The microspheres were then washed three times with 10 mL of deionized water and dried to obtain the surface-wrinkled microsphere adsorbent. The final product was designated as B3.

[0299] Comparative Example 4

[0300] S1 Preparation of the first microspheres

[0301] Preparation of the first polymer solution: Chitosan is dissolved in deionized water and mixed evenly to obtain the first polymer solution, wherein the mass fraction of chitosan in the first polymer solution is 1.5%;

[0302] Preparation of continuous phase: Span 80 and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8% and the remainder is n-octane;

[0303] Preparation of the collection phase: Span 80, glutaraldehyde and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8%, the mass fraction of glutaraldehyde is 1%, and the remainder is n-octane;

[0304] Implementing droplet microfluidics: 100 mL of the obtained first polymer solution and the dispersed phase were introduced into a fluid-focusing cross-shaped microfluidic channel for shearing. The flow rate of the first polymer solution was 2 mL / h, and the flow rate of the dispersed phase was 100 mL / h, forming chitosan microdroplets. These microdroplets were then cross-linked and solidified in the collected phase. Subsequently, the liquid was removed by centrifugation. The microspheres were then washed with 100%, 95%, and 75% ethanol aqueous solutions and deionized water, respectively. After drying, chitosan microspheres, i.e., the first microspheres, were obtained. The microfluidic chip was fluid-focusing type, with a microchannel diameter of 200 μm and a flow rate ratio of dispersed phase to continuous phase of 1:50.

[0305] S2 is used to prepare surface modification liquid.

[0306] Preparation of silver nitrate aqueous solution: Mix silver nitrate and water evenly to obtain a silver nitrate aqueous solution with a mass fraction of 0.2%;

[0307] Preparation of sodium borohydride aqueous solution: Mix sodium borohydride with water until homogeneous to obtain a sodium borohydride aqueous solution with a mass fraction of 1%;

[0308] Modified solution: Polyethyleneimine and water are mixed evenly to obtain a 2% (w / w) polyethyleneimine aqueous solution. Silver nitrate aqueous solution is added at a volume ratio of 10:1 (polyethyleneimine aqueous solution to silver nitrate aqueous solution). After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 (silver nitrate aqueous solution to sodium borohydride aqueous solution) under stirring to carry out a reduction reaction, thus obtaining the modified solution.

[0309] S3 Preparation of the Second Microsphere

[0310] 1 g of the first microsphere was soaked in 25 mL of 5.47% hydrochloric acid (1.5 mol / L) to allow it to swell fully. The swelling equilibrium was observed under a microscope. Then, the first microsphere that had reached swelling equilibrium was added to 25 mL of the modification solution and shaken on a shaker at room temperature for 2 hours. After that, it was allowed to stand and the supernatant was removed. Then, it was washed with water three times and finally the product, namely the second microsphere, was collected by centrifugation.

[0311] S4 Preparation of Surface-Wrinkled Microsphere Adsorbents

[0312] The collected second microspheres were placed in 25 mL of 5.71% sodium hydroxide solution (1.5 mol / L) and allowed to shrink completely. The mixture was stirred at 500 rpm for 12 hours, and the microspheres were collected by centrifugation. The microspheres were then washed three times with 10 mL of deionized water and dried to obtain assembled microspheres modified only by cationic polymer. The final product was designated as B4.

[0313] Comparative Example 5

[0314] S1 Preparation of the first microspheres

[0315] Preparation of the first polymer solution: Chitosan is dissolved in deionized water and mixed evenly to obtain the first polymer solution, wherein the mass fraction of chitosan in the first polymer solution is 1.5%;

[0316] Preparation of continuous phase: Span 80 and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8% and the remainder is n-octane;

[0317] Preparation of the collection phase: Span 80, glutaraldehyde and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8%, the mass fraction of glutaraldehyde is 1%, and the remainder is n-octane;

[0318] Implementing droplet microfluidics: 100 mL of the obtained first polymer solution and the dispersed phase were introduced into a fluid-focusing cross-shaped microfluidic channel for shearing. The flow rate of the first polymer solution was 2 mL / h, and the flow rate of the dispersed phase was 100 mL / h, forming chitosan microdroplets. These microdroplets were then cross-linked and solidified in the collected phase. Subsequently, the liquid was removed by centrifugation. The microspheres were then washed with 100%, 95%, and 75% ethanol aqueous solutions and deionized water, respectively. After drying, chitosan microspheres, i.e., the first microspheres, were obtained. The microfluidic chip was fluid-focusing type, with a microchannel diameter of 200 μm and a flow rate ratio of dispersed phase to continuous phase of 1:50.

[0319] S2 is used to prepare surface modification liquid.

[0320] Preparation of silver nitrate aqueous solution: Mix silver nitrate and water evenly to obtain a silver nitrate aqueous solution with a mass fraction of 0.2%;

[0321] Preparation of sodium borohydride aqueous solution: Mix sodium borohydride with water until homogeneous to obtain a sodium borohydride aqueous solution with a mass fraction of 1%;

[0322] Preparation of the first surface modification solution: Polyacrylic acid and water are mixed evenly to obtain a 4% (w / w) polyacrylic acid aqueous solution. Silver nitrate aqueous solution is added at a volume ratio of 10:1 (polyacrylic acid aqueous solution to silver nitrate aqueous solution). After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 (silver nitrate aqueous solution to sodium borohydride aqueous solution) under stirring to carry out a reduction reaction and obtain the first surface modification solution.

[0323] Preparation of the second surface modification solution: Polyethyleneimine and water are mixed evenly to obtain a 4% (w / w) polyethyleneimine aqueous solution. Silver nitrate aqueous solution is added at a volume ratio of 10:1 (polyethyleneimine aqueous solution to silver nitrate aqueous solution). After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 (silver nitrate aqueous solution to sodium borohydride aqueous solution) under stirring to carry out a reduction reaction, thereby obtaining the second surface modification solution.

[0324] S3 Preparation of the Second Microsphere

[0325] 1 g of the first microsphere was soaked in 35 mL of 5.47% hydrochloric acid (1.5 mol / L) to allow it to fully swell. The swelling equilibrium was observed under a microscope. Then, the first microsphere, after reaching swelling equilibrium, was added to 25 mL of the first surface modification solution and shaken on a shaker at room temperature for 2 hours. Then, 25 mL of the second surface modification solution was added and shaken on a shaker at room temperature for 2 hours. The mixture was then allowed to stand and the supernatant was removed. The microsphere was then washed three times with water. Finally, the product, the second microsphere, was collected by centrifugation. The final product was designated as B5.

[0326] Comparative Example 6

[0327] S1 Preparation of the first microspheres

[0328] Preparation of the first polymer solution: Chitosan is dissolved in deionized water and mixed evenly to obtain the first polymer solution, wherein the mass fraction of chitosan in the first polymer solution is 1.5%;

[0329] Preparation of continuous phase: Span 80 and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8% and the remainder is n-octane;

[0330] Preparation of the collection phase: Span 80, glutaraldehyde and n-octane are mixed evenly to obtain a continuous phase, wherein the mass fraction of Span is 8%, the mass fraction of glutaraldehyde is 1%, and the remainder is n-octane;

[0331] Implementing droplet microfluidics: 100 mL of the obtained first polymer solution and the dispersed phase were introduced into a fluid-focusing cross-shaped microfluidic channel for shearing. The flow rate of the first polymer solution was 2 mL / h, and the flow rate of the dispersed phase was 100 mL / h, forming chitosan microdroplets. These microdroplets were then cross-linked and solidified in the collected phase. Subsequently, the liquid was removed by centrifugation. The microspheres were then washed with 100%, 95%, and 75% ethanol aqueous solutions and deionized water, respectively. After drying, chitosan microspheres, i.e., the first microspheres, were obtained. The microfluidic chip was fluid-focusing type, with a microchannel diameter of 200 μm and a flow rate ratio of dispersed phase to continuous phase of 1:50.

[0332] S2 is used to prepare surface modification liquid.

[0333] Preparation of silver nitrate aqueous solution: Mix silver nitrate and water evenly to obtain a silver nitrate aqueous solution with a mass fraction of 0.2%;

[0334] Preparation of sodium borohydride aqueous solution: Mix sodium borohydride with water until homogeneous to obtain a sodium borohydride aqueous solution with a mass fraction of 1%;

[0335] Preparation of the modification solution: Polyacrylic acid and water are mixed evenly to obtain a 2% (w / w) polyacrylic acid aqueous solution. Silver nitrate aqueous solution is added at a volume ratio of 10:1 (polyacrylic acid aqueous solution to silver nitrate aqueous solution). After mixing evenly, sodium borohydride aqueous solution is added at a volume ratio of 2:1 (silver nitrate aqueous solution to sodium borohydride aqueous solution) under stirring to carry out a reduction reaction, thus obtaining the first surface modification solution.

[0336] S3 Preparation of the Second Microsphere

[0337] 1g of the first microspheres were soaked in 5.47% hydrochloric acid (1.5mol / L) to allow them to swell fully. The swelling equilibrium was observed under a microscope. The first microspheres that had reached swelling equilibrium were then added to 25mL of the modification solution and shaken on a shaker at room temperature for 2 hours. The mixture was then allowed to stand and the supernatant was removed. The microspheres were then washed three times with water and finally centrifuged to collect the product, which was the second microsphere.

[0338] S4 Preparation of Surface-Wrinkled Microsphere Adsorbents

[0339] The collected second microspheres were placed in 25 mL of 5.71% sodium hydroxide solution (1.5 mol / L) and allowed to shrink completely. The mixture was stirred at 500 rpm for 12 hours, and the microspheres were collected by centrifugation. The microspheres were then washed three times with 10 mL of deionized water and dried to obtain assembled microspheres modified only by anionic polymers. The final product was designated as B6.

[0340] Performance Test Examples

[0341] Performance Testing Example 1: Phosphorus Adsorption Performance Test

[0342] The products A2 prepared in Preparation Example 2, A5 prepared in Preparation Example 5, and B1-B6 prepared in Comparative Examples 1-6 were subjected to phosphorus adsorption performance testing. The experimental results are shown in Table 1 below, and the specific testing process is as follows.

[0343] Take 20 mg of the dried sample and add it to 10 mL of 12 mmol / L phosphate solution. Adjust the pH of the system to 2, and then shake and adsorb on a constant temperature shaker for 24 hours at 37 °C. After the reaction is complete, take the supernatant and measure the phosphate concentration. Calculate the adsorption capacity of the phosphate binder according to the following formula:

[0344]

[0345] In the formula, Q (mmol / g) represents the adsorption capacity of the phosphorus binder. Ci (mmol / L) and Cf (mmol / L) are the concentrations of phosphate in the solution before and after adsorption, respectively, and m (mg) is the mass of the phosphorus binder.

[0346] Table 1. Results of phosphorus adsorption performance tests

[0347] Sample number Adsorption capacity (mmol / g) Sample number Adsorption capacity (mmol / g) A2 2.61 B3 2.84 A5 2.93 B4 1.72 B1 1.61 B5 1.93 B2 1.72 B6 1.64

[0348] Experimental results show that the phosphorus binder prepared in Preparation Example 5 has an adsorption capacity of 2.93 mmol / g for phosphate at a phosphate solution concentration of 12 mmol / L and pH = 2. In comparison, the adsorption capacity of only the first microsphere in Comparative Example 1 as a phosphorus binder is 1.61 mmol / g, and the adsorption capacity of the microspheres without metal nanoparticles in Comparative Example 2 is 1.72. This may be because the product in Comparative Example 2 does not contain silver nanoparticles, thus failing to form an effective stress imbalance and a wrinkled structure (the surface structure is shown in the morphology characterization diagram). Figure 6 While the product in Comparative Example 5 contained silver nanoparticles, it did not complete the wrinkling process, resulting in only a slight increase in adsorption capacity compared to Comparative Example 2. In contrast, the anionic and cationic polymers in the surface-wrinkled microsphere adsorbent prepared in Example 5 attract each other through electrostatic interactions between positive and negative charges, forming a three-dimensional network or framework structure. This increases the effective adsorption area as a phosphorus binder. Simultaneously, the adsorbed phosphate molecules are effectively immobilized within the network structure. Therefore, the wrinkled structure increases the specific surface area of ​​the microspheres, improving the adsorption efficiency for phosphates (see schematic diagram). Figure 12Compared to Comparative Example 1, the adsorption capacities of the microsphere adsorbents with only a single layer of cationic polymer on the surface prepared in Comparative Example 4 and those with only a single layer of anionic polymer on the surface prepared in Comparative Example 6 were not significantly different. However, the adsorption capacity of microsphere adsorbent B4 with only a single layer of cationic polymer on the surface prepared in Comparative Example 4 was slightly higher than that of B6. This may be because the anionic polymer has the same charge as the phosphate molecules, and according to the principle of repulsion between like charges, its adsorption capacity for phosphate is slightly lower. Meanwhile, compared to the phosphate binder prepared in Preparation Example 5, although the adsorption capacity of product B3 prepared in Comparative Example 3 was not significantly different for phosphate, its content of metal nanoparticles was too high. Long-term use may lead to the accumulation of metals in the body, producing potential toxic side effects and environmental pollution during drug preparation. Therefore, considering the therapeutic value, cost value, and environmental value, the products in the comparative examples do not meet the optimal application requirements for phosphate binders.

[0349] Performance Test Example 2: Dynamic Change Test of Phosphorus Adsorption

[0350] The products A1, A3, and A8 prepared in Examples 1-8 were subjected to dynamic changes in phosphorus adsorption. The changes in adsorption curves are shown in the appendix. Figure 7 .

[0351] Take 20 mg of dried sample and add it to 10 mL of 12 mmol / L phosphate solution. Adjust the pH of the system to 2, and then shake and adsorb on a constant temperature shaker for 24 hours at 37 °C. Take the supernatant every hour to measure the phosphate concentration. Calculate the adsorption capacity of the phosphate binder according to the formula in Performance Test Example 1 and plot the curve.

[0352] The dynamic adsorption curves show that the phosphate concentration in the solution decreases rapidly in the first 2 hours, which may be due to the large number of adsorption sites on the surface of the phosphate binder, which have a strong binding force with phosphate ions; the rate of decrease then slows down, and adsorption equilibrium is reached after 5-6 hours.

[0353] Performance Testing Example 3: Cell Compatibility Test

[0354] Human renal tubular epithelial cells were co-cultured with product A2 prepared in Preparation Example 2, product B4 prepared in Comparative Example 4, product B6 prepared in Comparative Example 6, and serum-free low-glucose medium (control). Cell viability was assessed on days 1, 2, and 3, as detailed below. The results are suitable for... Figure 8 middle.

[0355] Serum-free low-glucose culture medium and CCK-8 reagent were prepared at a ratio of 9:1 under light-protected conditions. The original cell culture medium was then removed, and 200 μL of CCK-8 working solution was added to each well. The plate was then placed in a cell culture incubator at 37°C and 5% CO2 for 4 hours. After incubation, the working solution was gently mixed by pipetting, and the OD value of the sample at 450 nm was detected using a full-band microplate reader.

[0356] Experimental results: such as Figure 8 As shown, compared with the blank control, the cell viability of each treatment group was reduced. However, the cell viability of products B4 prepared in Comparative Example 4 and B6 prepared in Comparative Example 8 was the lowest, indicating that the products had a significant impact on cell proliferation and viability. However, although the cell viability of product A2 prepared in Preparation Example 2 was reduced, it still remained above 90%, indicating a relatively small adverse effect on cells. This suggests that product A2 can maintain a relatively stable structure in vivo. This stability helps improve the bioavailability and efficacy of the drug and reduce unnecessary drug dosage.

[0357] Performance Test Example 4: Phosphorus Reduction Performance Test

[0358] The products A1-A8 prepared in Preparation Examples 1-8 and the products B1 and B6 prepared in Comparative Examples 1 and 6 were used to treat rats with chronic kidney disease complicated with hyperphosphatemia, and the therapeutic effects were tested. The specific methods used were as follows:

[0359] (1) Construction of a rat model of chronic kidney disease complicated with hyperphosphatemia: Adenine was administered via gavage to 70 Sprague Dawley rats. After one week of acclimatization, the weight of each rat was measured and recorded. The rats were administered 10 mL of 3% adenine solution per kg of body weight (10 mL / kg) once daily for four weeks. The general condition of the rats was dynamically observed. Blood was collected from the inner canthus, and serum, urine, and fecal samples were also collected. The success of the model was determined by changes in renal function four weeks after modeling. The evaluation criterion was that the serum creatinine level in the model group should increase by approximately 4-5 times compared to the control group. Rats meeting the model criteria were used for subsequent experiments.

[0360] (2) The rats that successfully established the model were divided into several experimental groups and model groups: the experimental groups were given different doses of the sample by gavage; the model group rats were given 10 mL of physiological saline per kg of body weight (10 mL / kg) by gavage. The rats were given gavage once a day for 4 consecutive weeks during the experiment.

[0361] (3) On the days of gavage treatment at weeks 0, 2, and 4, blood was collected from the inner canthus of each rat, and serum, urine, and fecal samples were also collected. The levels of serum phosphorus, serum calcium, fecal phosphorus, fibroblast growth factor-23 (FGF-23), parathyroid hormone (PTH), and serum creatinine were measured.

[0362] The results of the performance test examples are shown in the table below.

[0363] Table 2 shows the results of A1 treatment in rats with hyperphosphatemia prepared in Example 1.

[0364]

[0365]

[0366] Table 3 shows the results of A2 treatment of hyperphosphatemic rats prepared in Example 2.

[0367]

[0368] Table 4 shows the results of A3 treatment of hyperphosphatemic rats prepared in Example 3.

[0369]

[0370] Table 5 shows the results of A4 treatment of hyperphosphatemic rats prepared in Example 4.

[0371]

[0372]

[0373] Table 6 shows the results of A5 treatment of hyperphosphatemic rats prepared in Example 5.

[0374] Table 7 shows the results of A6 treatment of hyperphosphatemic rats prepared in Example 6.

[0375]

[0376] Table 8 shows the results of A7 treatment of hyperphosphatemic rats prepared in Example 7.

[0377]

[0378] Table 9 shows the results of A8 treatment of hyperphosphatemic rats prepared in Example 8.

[0379]

[0380] Table 10 shows the results of B1 treatment in rats with hyperphosphatemia prepared in Comparative Example 1.

[0381]

[0382] Table 11 shows the results of B4 treatment in rats with hyperphosphatemia prepared in Comparative Example 4.

[0383]

[0384] Table 12 shows the results of B6 treatment in rats with hyperphosphatemia prepared in Comparative Example 6.

[0385]

[0386]

[0387] In addition, when preparing the A5 for treating hyperphosphatemia rats as described in Example 5, the thoracic aorta of rats in the control group, model group, and treatment group was collected after 4 weeks of treatment. Paraffin sections and alizarin red calcification staining were performed to observe the calcification of the rat thoracic aortic rings and to quantitatively analyze the calcification area. The results are shown in... Figure 9 and Figure 10 .

[0388] like Figure 9 and Figure 10 As shown, the thoracic aortic rings in the control group exhibited normal tissue structure with no calcified areas; the thoracic aorta of the model group rats showed severe calcification with discontinuous intima-media; while the experimental group treated with A5 effectively improved aortic calcification, with continuous thoracic aortic intima and reduced calcification area, thus confirming that the product provided by this invention not only has good phosphate adsorption capacity but also has vascular protective effects.

[0389] Analysis of the table above shows that the product prepared in this invention can bind to phosphate in the gastrointestinal tract, reducing phosphorus absorption and thus effectively lowering serum phosphate levels while increasing fecal phosphate levels. Simultaneously, it also reduces FGF-23 and PTH levels, improving calcium-phosphorus metabolic imbalance in chronic kidney disease and improving calcification of the thoracic aorta. Furthermore, no significant changes in renal function were observed in rats during treatment, confirming that the product of this invention does not adversely affect the rat kidneys, indicating its good biocompatibility. Moreover, compared to the product prepared in the comparative examples, the product prepared in these examples shows a better effect in lowering serum phosphate, possibly because the monolayer anionic or cationic polymer-modified microspheres failed to form a wrinkled microstructure, resulting in a smaller effective adsorption area. However, it should be noted that differences in the components, dosages, and processes used in the preparation of this invention may affect the therapeutic effect of the phosphate binder on hyperphosphatemia.

[0390] To compare whether there were differences in the retention time of products with different surface microstructures in the gastrointestinal tract, the retention time of A5 prepared in Preparation Example 5 and B1 prepared in Comparative Example 1 in the mouse gastrointestinal tract was monitored using an in vivo imaging system. Figure 9 As shown, there was no significant difference in fluorescence intensity between A5 and B1 in the in vivo and isolated gastrointestinal tracts at 0 and 4 hours after gavage. At 12 hours, the signal intensity of group A5 was significantly higher than that of group B1. At 24 hours after gavage, the signal intensity of group A5 remained significantly higher than that of group B1. These results indicate that group B1 was excreted more rapidly, while A5 significantly prolonged its retention time in the gastrointestinal tract. This may be due to the stronger adhesion ability of microspheres with surface folds compared to smooth microspheres, thus potentially improving the phosphorus adsorption efficiency of A5 in the gastrointestinal tract.

[0391] In summary, the phosphate binder provided by this invention is a potential effective drug for treating hyperphosphatemia. It not only has good phosphate adsorption capacity, but also has a long retention time in the gastrointestinal tract and exhibits good vascular protective effects.

[0392] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. A method for preparing a highly biocompatible surface-wrinkled microsphere adsorbent, characterized in that, Includes the following steps: S1. Preparation of the first microspheres: Prepare a first polymer solution and use the first polymer solution to prepare the first microspheres; S2. Preparation of the first surface modification solution: Prepare the second polymer solution, then add the first soluble metal salt. After the first soluble metal salt is completely dissolved and becomes a homogeneous solution, reduce the first soluble metal salt to the corresponding first metal nanoparticles to obtain the first surface modification solution. S3. Preparation of the second microsphere: Add the first microsphere prepared in step S1 to the first surface modification liquid prepared in step S2, and stir for more than 0.5 hours to obtain the second microsphere; S4. Preparation of surface-wrinkled microsphere adsorbent: The second microsphere prepared in step S3 is stirred in a shrinkage solution to wrinkle it, thereby obtaining the surface-wrinkled microsphere adsorbent of the present invention. In this process, the polymer in the first polymer solution (i.e., the first polymer) and the polymer in the second polymer solution (i.e., the second polymer) are attracted to each other, so that the second polymer can coat the surface of the first microsphere.

2. The preparation method according to claim 1, characterized in that, The first polymer in the first polymer solution may be a natural polymer and / or a synthetic polymer.

3. The preparation method according to claim 1, characterized in that, The solvent in the first polymer solution may be an organic solvent and / or an inorganic solvent.

4. The preparation method according to claim 1, characterized in that, The mass fraction of the first polymer in the first polymer solution is 0.5-20%.

5. The preparation method according to claim 1, characterized in that, The method for preparing the first microspheres using the first polymer solution can be spray drying, droplet microfluidics, or emulsion polymerization.

6. The preparation method according to claim 5, characterized in that, When the first polymer solution is prepared into the first microspheres using the spray spheroidizing method, the specific process is as follows: the first polymer solution, which is the dispersed phase, is sprayed into droplets using a spraying device and then solidified to obtain the first microspheres.

7. The preparation method according to claim 5, characterized in that, When the first polymer solution is used to prepare the first microspheres using droplet microfluidics, the specific process is as follows: the first polymer solution is injected into the microchannel of the droplet microfluidics device as both the dispersed phase and the continuous phase. Microdroplets are formed at the intersection of the dispersed phase and the continuous phase and flow into the collection phase. Then, solidification, liquid removal, and washing are performed to obtain the first microspheres.

8. The preparation method according to claim 5, characterized in that, When preparing the first microspheres from the first polymer solution using emulsion polymerization, the specific process is as follows: a solution that is incompatible with the first polymer solution is added as a continuous phase to the first polymer solution as a dispersed phase. After the system is mixed evenly, the dispersed phase is formed into microdroplets. Then, solidification, liquid removal, washing, and drying are performed to obtain the first microspheres.

9. A highly biocompatible surface-wrinkled microsphere adsorbent, characterized in that, The surface-wrinkled microsphere adsorbent is prepared by the preparation method according to any one of claims 1-8.

10. The application of a highly biocompatible surface-wrinkled microsphere adsorbent, characterized in that, The surface-wrinkled microsphere adsorbent is prepared by the preparation method according to any one of claims 1-8, and the application is in the pharmaceutical field. Specifically, the highly biocompatible surface-wrinkled microsphere adsorbent is used as a phosphate binder to treat hyperphosphatemia, or to prepare drugs for treating hyperphosphatemia, or to prepare sustained-release formulations, or to prepare weight-loss drugs and / or health products, or to prepare drugs and / or health products for weight control, or to prepare drugs and / or health products for lowering blood lipids, or to prepare drugs and / or health products for protecting blood vessels, or to prepare gastrointestinal mucosal protectants, or to prepare drugs and / or health products for regulating intestinal flora.

Images