Synthesis method of nano-enzyme with monosaccharide oxidase-like activity based on gold nanoparticle composite zirconium-based metal organic framework material

Abstract

The invention discloses a synthesis method of nano-enzyme with monosaccharide oxidase-like activity based on a gold nanoparticle composite zirconium-based metal organic framework material. The metal organic framework material is a porous coordination high-molecular polymer crystal formed by coordination of metal ions and organic ligands. On the other hand, the metal organic framework material has the advantages of large specific surface area, high porosity, adjustable pore structure, high catalytic activity, open metal active sites, structural diversity and the like, so that the metal organic framework material is often used as a catalytic material or a carrier material of a catalyst. According to the invention, gold nanoparticles (Au NPs) are compounded on a zirconium-based metal organic framework material by reducing a compound containing gold in a positive electrovalence state or complexing ions, and the zirconium-based metal organic framework material can also be loaded on other loading materials, so that the nano enzyme with monosaccharide oxidase-like activity is obtained. The method has the advantages of simple operation, simple procedure and the like.

Description

Technical Field

[0001] The invention relates to the fields of gold nanoparticle composite zirconium-based metal organic framework materials and nanozyme synthesis, and in particular to a method for synthesizing a nanozyme with monosaccharide oxidase-like activity based on gold nanoparticle composite zirconium-based metal organic framework materials. Background Art

[0002] Metal-organic framework (MOF) is a porous coordination polymer crystal formed by the coordination of metal ions and organic ligands. Metal-organic framework materials are mainly classified into three categories according to organic ligands: carboxylic acid, nitrogen heterocyclic and phosphonic acid. Among them, carboxylic acid metal-organic framework materials are the most common, and carboxylic acids mostly use terephthalic acid, trimesic acid, etc.; nitrogen heterocyclic MOFs mainly use imidazole esters, bipyridines, etc. as organic ligands. Phosphonic acid metal-organic framework materials are relatively rare because it is difficult to obtain an ideal structure. Because it has many advantages such as large specific surface area, high porosity, adjustable pore structure, high catalytic activity, open metal active sites, structural diversity, etc., it is often used as a catalytic material or a carrier material for a catalyst. On the other hand, some research works have reported that gold nanoparticles (Au NPs) have glucose oxidase-like activity. The present invention discloses a method for synthesizing a nanozyme having monosaccharide oxidase-like (including glucose oxidase) activity based on gold nanoparticles composite zirconium-based metal-organic framework materials. Summary of the invention

[0003] By reducing compounds or complex ions containing positively charged gold, gold nanoparticles (Au NPs) are composited on zirconium-based metal organic framework materials, wherein the zirconium-based metal organic framework materials can also be supported on other load materials to obtain nanozymes with monosaccharide oxidase-like activity. This synthesis method has the advantages of easy operation and simple procedures.

[0004] Furthermore, the gold nanoparticle composite zirconium-based metal organic framework material described in this patent refers to gold nanoparticles adsorbed and deposited on the surface or in the pores of the zirconium-based metal organic framework material;

[0005] Furthermore, the zirconium-based metal organic framework material described in this patent refers to a metal organic framework material synthesized with zirconium-based metal ions as metal coordination centers, and its ligand is an organic compound containing two or more coordination atoms, including but not limited to terephthalic acid, trimesic acid, imidazoles, bipyridines and other organic compounds;

[0006] Furthermore, the zirconium-based metal organic framework material described in this patent includes a zirconium-based metal organic framework material carried on a load material, and the load material includes but is not limited to graphene, carbon nanotubes, carbon fibers, activated carbon, etc. and their derivative materials;

[0007] Furthermore, the gold nanoparticles described in this patent are obtained by reducing a compound or complex ion containing positively charged gold by a reducing agent, wherein the compound or complex ion containing positively charged gold includes but is not limited to chloroauric acid, and the reducing agent includes but is not limited to sodium borohydride;

[0008] Furthermore, the monosaccharides described in this patent include but are not limited to glucose, fructose, galactose, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 shows the specific activity comparison of glucose oxidase-like enzymes of different materials with glucose as substrate. UiO66 = Zr-PTA MOF material. rGO = reduced graphene oxide. Working buffer: pH, 5.1, 50 mM HAc-NaAc. Temperature: 40 o C.

[0010] Figure 2 Comparison of the specific monosaccharide oxidase-like activity of Au / Uio66 / rGO with glucose and fructose as substrates. UiO66 = Zr-PTA MOF material. rGO = reduced graphene oxide. Working buffer: pH 5.1, 50 mM HAc-NaAc. Temperature: 40 o C.

[0011] Figure 3 Glucose oxidase activity of Au-Zr-BTC MOF material was tested with glucose as substrate. Au-Zr-BTC MOF catalyzes glucose oxidation to produce hydrogen peroxide. Hydrogen peroxide oxidizes 3,3',5,5'-tetramethylbenzidine (TMB) under the catalysis of horseradishperoxidase (HRP). The oxidized TMB has a characteristic absorption peak at 652 nm. Working buffer: pH, 5.1, 50 mM HAc-NaAc. Incubation temperature: 45 o C. Duration: 5 min.

[0012] Figure 4Comparison of the monosaccharide oxidase activity of Au-Zr-BTC MOF materials with glucose and fructose as substrates. Au-Zr-BTC MOF catalyzes the oxidation of glucose to produce hydrogen peroxide. Hydrogen peroxide oxidizes 3,3',5,5'-tetramethylbenzidine (TMB) catalyzed by horseradish peroxidase (HRP), and the oxidized TMB has a characteristic absorption peak at 652 nm. Working buffer: pH 7.5, 50 mM HAc-NaAc. Temperature: 30 o C. Duration: 5 min. DETAILED DESCRIPTION

[0013] The specific embodiments of the nanozyme synthesis method of the present invention are described in detail below with reference to the accompanying drawings.

[0014] (1) Weigh 15.0 mg of graphene oxide (GO) and disperse it in 60.0 mL of N,N-dimethylformamide (DMF). Ultrasonicate for 30 min to obtain solution A. Weigh 150 mg of 1,4-terephthalic acid (PTA) and dissolve it in 30.0 mL of solution A to obtain solution B. Weigh 0.2004 g of zirconium tetrachloride (ZrCl4) and dissolve it in another 30.0 mL of solution A and add 4.20 mL of glacial acetic acid (HAc) to obtain solution C. Add solution C to solution B under stirring, transfer the mixture into a reactor, and place it in an oven at 120 °C for 24 h. After the reaction is completed, the oven is closed and cooled to room temperature. The resulting suspension is centrifuged (10,000 rpm, 3 min) and then washed twice with DMF and methanol alternately. The product is placed in a vacuum drying oven at 60 ° C for 12 h. After grinding, the Zr-PTA MOF material (UiO-66) loaded on reduced graphene oxide (rGO) is obtained, namely UiO66 / rGO. According to this synthesis procedure, UiO-66 is obtained without adding GO to solution A. According to this synthesis procedure, PTA is not added to solution B, and ZrCl4 is not added to solution C, and rGO is obtained.

[0015] 150 mg UiO-66 / rGO was weighed and dispersed in 60.0 mL methanol. 15.0 mL 20.0 mM chloroauric acid (HAuCl4) solution was added under stirring (500 rpm) and continued to stir for 30 min. Then 3.00 mL freshly prepared sodium borohydride (NaBH4) solution (2.50 M) was added dropwise and continued to stir for 2 h to reduce Au3+ to Au NPs. After the reaction was completed, the resulting mixture was centrifuged, washed with methanol 3 times, placed in a drying oven at 60 ° C for 12 h, and Au / UiO-66 / rGO was obtained after grinding as a black solid powder. After replacing UiO-66 / rGO with UiO-66 and rGO, the above experiment was repeated to obtain Au / UiO-66 and Au / rGO.

[0016] (2) 0.174 g of ZrCl4 and 0.706 g of trimesic acid (BTC) were accurately weighed and then dissolved in 12.5 mL of DMF. Ultrasonic treatment was performed for 30 minutes to ensure that all solid matter was completely dissolved. Then 3.2 mL of acetic acid was slowly added to the mixed solution while stirring at 500 rpm for 30 minutes until a uniform white suspension was formed. The obtained white suspension was poured into a reactor and heated at 135 °C for 24 hours. After the reaction was completed, the reactor was removed and allowed to cool naturally to ambient temperature, and a milky white solution was finally obtained. The milky white solution was centrifuged using a high-speed centrifuge (speed 10000 rpm, centrifugation for 3 minutes), and then washed three times with DMF and anhydrous ethanol respectively to remove impurities. After washing, it was dried at 60 °C for 12 hours, and the solid matter was ground into powder to obtain a white powdery Zr-BTCMOF material. Then disperse 0.150 g of the prepared Zr-BTC MOF powder in 60 mL of methanol, add 7.5 mL of HAuCl4 with a concentration of 20 mM, and stir at 500 rpm for 30 minutes at room temperature. After that, add the newly prepared sodium borohydride dropwise and continue to stir at 500 rpm for 2 hours to obtain a black-purple solution. After the reaction is completed, the black-purple solution is centrifuged again using a high-speed centrifuge (speed 10000 rpm, centrifugation for 3 minutes), and then washed three times with methanol to remove the residue. After washing, dry at 60 ° C for 12 hours, and grind the solid matter into powder to obtain a purple-black powder Au-Zr-MOF.

Claims

1. A method for synthesizing nanozymes with monosaccharide oxidase-like activity based on gold nanoparticles composite zirconium-based metal organic framework materials, characterized in that: Gold nanoparticles (Au nanoparticles, Au NPs) are composited on a zirconium-based metal-organic framework material by reducing compounds containing positively charged gold or complex ions, wherein the zirconium-based metal-organic framework material can also be supported on other load materials to obtain a nanozyme with monosaccharide oxidase-like activity.

2. The method according to claim 1, characterized in that The gold nanoparticle composite zirconium-based metal organic framework material refers to gold nanoparticles adsorbed and deposited on the surface or in the pores of the zirconium-based metal organic framework material.

3. The method according to claim 1, characterized in that The zirconium-based metal organic framework material refers to a metal organic framework material synthesized with zirconium-based metal ions as metal coordination centers, and its ligands are organic compounds containing two or more coordination atoms, including but not limited to terephthalic acid, isophthalic acid, imidazoles, bipyridines and other organic compounds.

4. The method according to claim 1, characterized in that: The zirconium-based metal organic framework material includes a zirconium-based metal organic framework material supported on a load material, and the load material includes but is not limited to graphene, carbon nanotubes, carbon fibers, activated carbon, and the like and their derivative materials.

5. The method according to claim 1, characterized in that The gold nanoparticles are obtained by reducing a compound or complex ion containing positively charged gold by a reducing agent. The compound or complex ion containing positively charged gold includes but is not limited to chloroauric acid, and the reducing agent includes but is not limited to sodium borohydride.

6. The method according to claim 1, characterized in that The monosaccharides include but are not limited to glucose, fructose, galactose and the like.

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