Porous hydrogel with high catalytic performance and preparation method and application thereof

Abstract

The application provides a porous hydrogel with high catalytic performance and a preparation method and application thereof, the nanoparticle immobilized enzyme contained in the porous hydrogel enhances the enzyme immobilization effect, plays a certain leakage prevention effect, and prolongs the service life; the metal nanoparticles can perform charge transmission while catalyzing the conversion of glucose, so that the hydrogel has certain conductivity, thereby establishing a good catalytic sensing environment; meanwhile, the porous hydrogel has the catalytic property and oxygen carrying property of the nanoparticle immobilized enzyme and certain viscoelasticity, and has good biocompatibility; the porous hydrogel is formed by heat polymerization, the hydrogel prepared has a reticular structure in the inside, has a high specific surface area, and the preparation method can adjust the pore size of the hydrogel by adjusting the use ratio of the carboxymethylated cellulose nanofiber and betaine, so as to obtain the hydrogel matched with a higher enzyme loading capacity, so that the hydrogel has higher catalytic capacity and has wide application prospects in electrochemical sensors.

Description

Technical Field

[0001] This invention relates to the field of biocatalytic materials technology, and in particular to a porous hydrogel with high catalytic performance, its preparation method and application. Background Technology

[0002] Enzymes, naturally occurring nanoscale protein catalysts, have been widely applied in numerous fields such as biology and chemistry as a common oxidation method. Today, the size of enzyme-based catalytic materials can be reduced to the nanoscale, thus improving the efficiency of enzyme catalysis. However, the reduced size also makes enzyme catalytic materials more difficult to reuse. Therefore, the development of efficient chemical transformation catalytic systems with advantages such as high activity, durability, operability, and biocompatibility has attracted considerable attention.

[0003] With advancements in the highly controllable fabrication and processability of novel biomaterials, polymer hydrogel-based enzyme composites have become a common strategy. Their swellable, nanoporous / microporous, and aqueous 3D structures enable the immobilization of catalytic enzymes, electroactive substances, whole cells, and complex tissue models. Furthermore, their environmentally friendly processes and designable catalytic reactions enhance the practicality and cost-effectiveness of enzyme catalysts, allowing for the maintenance of tunable mechanical properties in wearable and implantable devices. Therefore, the synthesis of hydrogel-based composite enzyme catalytic materials is currently under extensive research.

[0004] However, most of these hydrogel composite enzyme catalytic materials suffer from low enzyme loading or even enzyme leakage, resulting in low catalytic performance and short lifespan. Therefore, how to develop high-performance catalytic systems for biological and chemical sensing applications has become an urgent technical problem to be solved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a porous hydrogel with high catalytic performance.

[0006] Another technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned porous hydrogel with high catalytic performance.

[0007] Another technical problem to be solved by the present invention is to provide the application of the above-mentioned porous hydrogel with high catalytic performance.

[0008] The technical solution adopted in this invention is:

[0009] A porous hydrogel with high catalytic performance is a copolymer porous hydrogel with an internal network structure, wherein nanoparticle-immobilized enzymes and metal nanoparticles are dispersed. The nanoparticle-immobilized enzymes are Al2O3 nanoparticles as immobilization carriers with enzymes modified on their surfaces, and the metal nanoparticles are single gold or alloy nanoparticles with high catalytic performance.

[0010] Preferably, the porous hydrogel with high catalytic performance is prepared by incorporating enzymes and metal nanoparticles immobilized in the porous hydrogel.

[0011] The enzyme immobilized in the aforementioned porous hydrogel with high catalytic performance is achieved by modifying the enzyme onto the surface of Al2O3 nanoparticles. Good enzyme encapsulation is achieved through the selection of nanoparticle size and stability. Furthermore, the stability and concentration of the immobilized enzyme in the hydrogel are ensured by selecting the raw material ratio and preparation method. The metal nanoparticles, through the selection of their material properties and ratios, can simultaneously serve as a catalyst and a conductive material to enhance the catalytic performance and conductivity of the hydrogel.

[0012] Preferably, in the above-mentioned porous hydrogel with high catalytic performance, the Al2O3 nanoparticles have a diameter of 10-20 nm, and the size of the enzyme immobilized in the nanoparticles is 15-25 nm.

[0013] Preferably, in the above-mentioned porous hydrogel with high catalytic performance, the enzyme is a protein enzyme or an RNA enzyme.

[0014] Preferably, in the above-mentioned porous hydrogel with high catalytic performance, the enzyme is glucose oxidase.

[0015] Preferably, in the above-mentioned porous hydrogel with high catalytic performance, the metal nanoparticles are platinum nanoparticles, gold nanoparticles, or silver nanoparticles.

[0016] The above-mentioned porous hydrogel with high catalytic performance is prepared by constructing carboxylated cellulose nanofibers and betaine through an electrostatic binding mechanism. The specific steps are as follows:

[0017] (1) Using Al2O3 nanoparticle emulsion as emulsifier, add enzyme solution, and prepare enzyme-loaded nanoparticle immobilized enzyme solution by shaking using ice-water bath method.

[0018] (2) Dissolve betaine monomer in carboxylated cellulose nanofiber solution, add crosslinking agent and sonicate the solution under ice-water bath conditions, then add crosslinking catalyst and thermal initiator to the solution and stir in ice-water bath to obtain zwitterionic polymer solution.

[0019] (3) Add metal nanoparticles to the zwitterionic polymer solution obtained in step (2) and mix the solution evenly under ice-water bath conditions;

[0020] (4) Add the nanoparticle-immobilized enzyme solution to the zwitterionic mixture solution obtained in step (3), place it in an ice-water bath and stir to obtain a hydrogel solution, inject the hydrogel solution into a mold, and polymerize it under hot water bath conditions to obtain a porous hydrogel with high catalytic performance.

[0021] Preferably, in the above-mentioned method for preparing porous hydrogels with high catalytic performance, the concentration of Al2O3 nanoparticle emulsion in step (1) is 0.1-5 mg / ml, the concentration of enzyme solution is 10-50 mg / ml, the ice-water bath temperature is -10-0℃, the shaking speed of the shaker is 100-200 r / min, and the shaking time is 15-45 min.

[0022] Preferably, in the above-mentioned method for preparing porous hydrogels with high catalytic performance, the volume ratio of Al2O3 nanoparticle emulsion to enzyme solution in step (1) is 1:1.

[0023] Preferably, in the above-mentioned method for preparing porous hydrogels with high catalytic performance, the carboxylated cellulose nanofiber solution in step (2) is a carboxylated cellulose nanofiber solution with a mass fraction of 1% to 10%, the betaine monomer is a powder with a betaine monomer active content of 94% to 98%; the crosslinking agent is methylenebisacrylamide, the catalytic crosslinking agent is tetramethylethylenediamine, and the thermal initiator is ammonium persulfate; the ultrasonic time is 30 to 60 min, the ice-water bath temperature is -10 to 0℃, the stirring speed is 300 to 450 rpm, and the stirring time is 3 to 15 min.

[0024] Preferably, in the above-mentioned method for preparing porous hydrogels with high catalytic performance, the betaine monomer is sulfonate betaine or phosphate betaine.

[0025] Preferably, in the above-mentioned method for preparing porous hydrogels with high catalytic performance, the volume ratio of metal nanoparticles to zwitterionic polymer solution in step (3) is 0.01 to 0.05:1, and the ice-water bath temperature is -10 to 0°C.

[0026] Preferably, in the above-mentioned method for preparing porous hydrogels with high catalytic performance, the volume ratio of the nanoparticle immobilized enzyme solution and the zwitterionic mixed solution in step (4) is 0.1-10:1, the ice-water bath temperature is -10 to 0°C, the stirring speed is 300 to 450 rpm, and the stirring time is 3 to 15 min; the hot water bath temperature is 30 to 40°C, and the polymerization time is 24 to 36 h.

[0027] The above-mentioned porous hydrogels with high catalytic performance are used in electrochemical sensors.

[0028] Preferably, the above-mentioned porous hydrogel with high catalytic performance is used as a sensing material in an electrochemical sensor.

[0029] The beneficial effects of this invention are:

[0030] The porous hydrogel with high catalytic performance incorporates nanoparticles that immobilize enzymes, enhancing enzyme immobilization, preventing leakage, and extending service life. Metal nanoparticles facilitate charge transfer during glucose conversion, giving the hydrogel conductivity and creating a favorable catalytic sensing environment. Simultaneously, the hydrogel possesses the catalytic properties and oxygen-carrying capacity of the nanoparticle-immobilized enzyme, along with viscoelasticity and good biocompatibility, making it easier to replace when adhering to skin or other tissues. The porous hydrogel is formed via thermal polymerization, offering a simple and rapid process. The resulting hydrogel exhibits a network structure with a high specific surface area. Its preparation method allows for adjustment of the pore size by varying the ratio of carboxylated cellulose nanofibers to betaine, achieving a hydrogel with a high enzyme loading capacity and thus high catalytic activity. This makes it a promising candidate for applications in electrochemical sensors. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the porous hydrogel with high catalytic performance described in this invention;

[0032] Figure 2 This is a schematic diagram of the structure of enzyme-loaded nanoparticles in the high-catalytic-performance porous hydrogel described in this invention. Detailed Implementation

[0033] To further illustrate the present invention, the following embodiments are provided for detailed explanation:

[0034] Example 1

[0035] A porous hydrogel with high catalytic performance is prepared by the following steps:

[0036] (1) Synthesis of enzyme solution immobilized with nanoparticles

[0037] Take 10 ml of a 1 mg / ml Al2O3 nanoparticle emulsion (with a diameter of 10-20 nm) in a beaker. Add 10 ml of a 30 mg / ml glucose oxidase solution to the beaker. Place the beaker in ice water at -5°C and shake on a shaker for 30 minutes to obtain a homogeneous nanoparticle-immobilized enzyme solution with the structure shown below. Figure 2 As shown.

[0038] (2) Preparation of hydrogel zwitterionic polymer solution

[0039] Take 50 ml of 2% carboxylated cellulose nanofiber solution in a beaker, dissolve 10 mg of sulfonate betaine monomer in the carboxylated cellulose nanofiber solution to prepare a zwitterionic monomer solution; prepare 1% methylenebisacrylamide solution, take 6 ml of 1% methylenebisacrylamide solution and add it to the monomer solution, place the beaker in an ultrasonic machine, and sonicate for 30 min under ice water conditions at -5℃; after sonication, add 6 ml of 2% ammonium persulfate and 10 μl of 1% tetramethylethylenediamine to the above mixed solution, place the beaker in ice water at -5℃, and stir with a stirrer at 300 rpm for 10 min to obtain a hydrogel zwitterionic polymer solution.

[0040] (3) Preparation of porous hydrogels with high catalytic performance

[0041] Platinum nanoparticles with a solute mass fraction of 1% were added to a prepared hydrogel zwitterionic polymer solution and mixed thoroughly in ice water at -5°C. Then, the prepared nanoparticle-immobilized enzyme solution and the mixed platinum nanoparticle hydrogel zwitterionic solution were mixed in a 1:1 ratio in a beaker. The beaker was placed in ice water at -5°C and stirred at 300 rpm for 10 min to obtain a hydrogel mixture. The hydrogel mixture was injected into a mold and polymerized at 37°C in a hot water bath for 24 h to obtain a porous hydrogel with high catalytic performance. The structure of the porous hydrogel is as follows. Figure 1 As shown.

[0042] In the preparation method of the aforementioned porous hydrogel with high catalytic performance, an amphoteric hydrogel was first synthesized using carboxylated cellulose nanofibers and sulfonated betaine. The amphoteric hydrogel provides a high specific surface area, and the pore size can be adjusted by changing the proportion of carboxylated cellulose nanofibers to match the maximum enzyme adsorption concentration, thereby increasing the enzyme loading. Furthermore, to enhance enzyme immobilization, enzyme-Al2O3 particles were synthesized by modifying the Al2O3 surface, and these particles were incorporated into the amphoteric hydrogel to obtain a porous catalytic hydrogel with high enzyme loading. Finally, metal nanoparticles were added to the hydrogel, improving both catalytic activity and conductivity. This porous hydrogel with high catalytic performance prevents enzyme leakage and establishes a favorable catalytic environment through adhesion to the surrounding environment. Its excellent conductivity and high catalytic performance demonstrate significant value for clinical applications.

[0043] Example 2

[0044] The sensor electrode was placed in a hydrogel container, and the hydrogel mixture solution prepared in step (3) of Example 1 was dropped onto the sensor electrode until the hydrogel spread to the electrode. The container was then placed in a water bath and polymerized at 37°C for 24 hours, thus encapsulating the sensor electrode with a porous hydrogel modified with high catalytic performance.

[0045] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a porous hydrogel with high catalytic performance, characterized in that: The method involves constructing carboxylated cellulose nanofibers and betaine via an electrostatic binding mechanism, with the specific steps outlined below: (1) Using Al2O3 nanoparticle emulsion as emulsifier, an enzyme solution was added and the enzyme was prepared by shaking using an ice-water bath method. The enzyme was glucose oxidase. (2) Dissolve betaine monomer in carboxylated cellulose nanofiber solution, add crosslinking agent and sonicate the solution under ice-water bath conditions, then add crosslinking catalyst and thermal initiator to the solution and stir in ice-water bath to obtain zwitterionic polymer solution, wherein the betaine monomer is sulfonate betaine monomer; (3) Add metal nanoparticles to the zwitterionic polymer solution obtained in step (2), and mix the solution evenly under ice-water bath conditions. The metal nanoparticles are platinum nanoparticles. (4) Add the nanoparticle immobilized enzyme solution to the zwitterionic mixture solution obtained in step (3), place it in an ice-water bath and stir to obtain a hydrogel solution, inject the hydrogel solution into a mold, and polymerize it under hot water bath conditions to obtain a porous hydrogel with high catalytic performance.

2. The method for preparing a porous hydrogel with high catalytic performance according to claim 1, characterized in that: In step (1), the concentration of the Al2O3 nanoparticle emulsion is 0.1–5 mg / ml, and the concentration of the enzyme solution is 10–50 mg / ml; the ice-water bath temperature is -10–0℃, the shaking speed is 100–200 r / min, and the shaking time is 15–45 min; in step (2), the carboxylated cellulose nanofiber solution is a 1%–10% carboxylated cellulose nanofiber solution, and the betaine monomer is a powder with an active betaine monomer content of 94%–98%; the crosslinking agent is methylenebisacrylamide, the catalytic crosslinking agent is tetramethylethylenediamine, and the thermal initiator is ammonium persulfate; the ultrasonic time is 30–60 min, the ice-water bath temperature is -10–0℃, the stirring speed is 300–450 rpm, and the stirring time is 3–15 min. min; in step (3), the volume ratio of metal nanoparticles to zwitterionic polymer solution is 0.01 to 0.05:1, and the ice-water bath temperature is -10 to 0℃; in step (4), the volume ratio of nanoparticle immobilized enzyme solution to zwitterionic mixed solution is 0.1 to 10:1, the ice-water bath temperature is -10 to 0℃, the stirring speed is 300 to 450 rpm, and the stirring time is 3 to 15 min; the hot water bath temperature is 30 to 40℃, and the polymerization time is 24 to 36 h.

3. The method for preparing a porous hydrogel with high catalytic performance according to claim 1 or 2, characterized in that: In step (1), the volume ratio of Al2O3 nanoparticle emulsion to enzyme solution is 1:

1.

4. The method for preparing a porous hydrogel with high catalytic performance according to claim 1 or 2, characterized in that: The Al2O3 nanoparticles have a diameter of 10-20 nm, and the enzyme immobilized in the nanoparticles has a size of 15-25 nm.

5. A porous hydrogel with high catalytic performance, characterized in that: It is prepared by the preparation method described in any one of claims 1-4.

6. The application of the porous hydrogel with high catalytic performance as described in claim 5 in electrochemical sensors.

7. The application of the porous hydrogel with high catalytic performance according to claim 6, characterized in that: The porous hydrogel is used as a sensing material in an electrochemical sensor.

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