阅读说明：本技术 一种纳米金属有机框架增韧的高强度荧光水凝胶及其制备方法 (Nano metal organic framework toughened high-strength fluorescent hydrogel and preparation method thereof ) 是由 汤力 龚亮 许月 汤建新 于 2021-08-12 设计创作，主要内容包括：本发明公开了一种纳米金属有机框架增韧的高强度荧光水凝胶制备方法,步骤为合成2-乙烯基-咪唑单体；采用2-乙烯基-咪唑单体制备包覆有有机荧光分子纳米颗粒；采用V-ZIF-8纳米颗粒制备有机荧光分子@V-ZIF-8纳米颗粒；制备基于OFM@V-ZIF-8纳米颗粒的高强度荧光水凝胶。本发明采用具有类沸石结构的ZIF-8结构,通过设计配体得到V-ZIF-8纳米颗粒,可以封装有机荧光分子,还可以引入双键,起到交联剂作用,进一步合成得到OFM@V-ZIF-8纳米颗粒,最后制备得到的荧光水凝胶不仅具有UV光刺激响应性,还具有更强的机械性能,减少了对交联剂的消耗,在各领域展现了更大的应用潜力。(The invention discloses a preparation method of a high-strength fluorescent hydrogel toughened by a nano metal organic framework, which comprises the following steps of synthesizing a 2-vinyl-imidazole monomer; preparing organic fluorescent molecule-coated nano particles by adopting a 2-vinyl-imidazole monomer; preparing organic fluorescent molecules @ V-ZIF-8 nanoparticles by adopting the V-ZIF-8 nanoparticles; preparing the high-intensity fluorescent hydrogel based on the OFM @ V-ZIF-8 nanoparticles. According to the invention, a ZIF-8 structure with a zeolite-like structure is adopted, V-ZIF-8 nano particles are obtained by designing a ligand, organic fluorescent molecules can be packaged, double bonds can be introduced to play a role of a cross-linking agent, OFM @ V-ZIF-8 nano particles are further synthesized, and the finally prepared fluorescent hydrogel not only has UV light stimulation responsiveness, but also has stronger mechanical properties, reduces the consumption of the cross-linking agent, and shows greater application potential in various fields.)

1. A preparation method of a high-strength fluorescent hydrogel toughened by a nano metal organic framework is characterized by comprising the following steps:

(1) synthesizing a 2-vinyl-imidazole monomer;

(2) preparing V-ZIF-8(OFM @ V-ZIF-8) nanoparticles coated with Organic Fluorescent Molecules (OFM) by adopting 2-vinyl-imidazole monomers;

(3) preparing the high-intensity fluorescent hydrogel based on the OFM @ V-ZIF-8 nanoparticles.

2. The method for preparing the nano-metal organic framework toughened high-strength fluorescent hydrogel according to claim 1, wherein the specific operation method for synthesizing the 2-vinyl-imidazole monomer in the step (1) comprises the following steps:

1) dissolving methyl triphenyl phosphorus iodide and potassium tert-butoxide in an anhydrous tetrahydrofuran solvent at room temperature, and filling nitrogen gas at 500-;

2) adding 2-imidazole formaldehyde into the solution obtained in the step 1), and continuously stirring at 500-800rpm for reaction for 24-36h at room temperature;

3) adding excessive ammonium chloride into the solution obtained in the step 2) to quench the reaction to obtain a reaction mixture;

4) extracting the reaction mixture with ethyl acetate, collecting an organic phase, washing the organic phase for 3-5 times by using saturated saline solution, drying the organic phase by using anhydrous magnesium sulfate, and rotationally evaporating the organic solvent at the temperature of 30-50 ℃ at the rotating speed of 20-40rpm to obtain a crude product;

5) purifying the crude product by using a silica gel column, collecting the product, and rotationally evaporating to dryness at the temperature of 30-50 ℃ and the rpm of 20-40 to obtain the 2-vinyl-imidazole monomer.

3. The method for preparing the nano-metal organic framework toughened high-intensity fluorescent hydrogel according to claim 2, wherein the molar ratio of methyl triphenyl phosphonium iodide to potassium tert-butoxide in step 1) is 1: 1.05;

the molar ratio of the methyl triphenyl phosphonium iodide to the 2-imidazole formaldehyde is 1: 0.5;

the silica gel column purification in the step 5) adopts petroleum ether: the mass ratio of ethyl acetate is 2: 3 as a detergent.

4. The preparation method of the nanometal organic framework toughened high-strength fluorescent hydrogel according to claim 1, wherein the specific operation method of preparing the Organic Fluorescent Molecule (OFM) coated V-ZIF-8(OFM @ V-ZIF-8) nanoparticles by using the 2-vinyl-imidazole monomer in the step (2) is as follows:

1) adding Zn (NO)₃)₂·6H₂O, organic fluorescent molecule, and 2-vinyl-imidazole monomer were dissolved in anhydrous methanol, respectively, and Zn (NO) was added at room temperature₃)₂·6H₂Quickly pouring the O methanol solution into the methanol solution of the 2-vinyl-imidazole and the organic fluorescent molecules, and stirring at the room temperature at the speed of 500-800rpm for 1-2h to obtain a mixed solution;

2) centrifuging the mixed solution at 8000-;

3) and re-dispersing the washed precipitate in methanol for later use to obtain the nano OFM @ V-ZIF-8 nano-particle methanol dispersion liquid.

5. The method for preparing the nano metal organic framework toughened high-intensity fluorescent hydrogel as claimed in claim 4, wherein the organic fluorescent molecule Zn (NO) in the step 1)₃)₂·6H₂The molar ratio of O to 2-vinyl-imidazole monomer is 0.5:1: 5. The organic fluorescent micromolecules in the step 1) are one or more of rhodamine B, fluorescein and 7-hydroxycoumarin.

6. The preparation method of the high-strength fluorescent hydrogel toughened by the nano metal organic framework, according to claim 1, is characterized in that the specific operation method for preparing the high-strength fluorescent hydrogel based on the OFM @ V-ZIF-8 nanoparticles in the step (3) is as follows:

1) centrifuging 10mL of OFM @ V-ZIF-8 nanoparticle methanol dispersion liquid at 8000-;

2) adding an aqueous solution of N-hydroxyethyl acrylamide, gelatin, a photoinitiator 2959 and OFM @ V-ZIF-8 into a glass bottle filled with water, hermetically stirring, pumping air, filling nitrogen for 3 times, and continuously stirring in a water bath kettle at the temperature of 60-80 ℃ until all reactants are completely dissolved to obtain a pre-polymerization solution;

3) injecting the pre-polymerization solution into a glass mold through an injector, and naturally cooling to room temperature to form single-network gelatin gel;

4) and transferring the mould to a 8W ultraviolet lamp for polymerization for 1-1.5h, and forming a V-ZIF-8 crosslinked poly N-hydroxyethyl acrylamide second network through photoinitiated polymerization reaction. Finally obtaining the high-strength fluorescent hydrogel toughened by the nano metal organic framework, which is named as OFM @ V-ZIF-8DN hydrogel.

7. The method for preparing the nano-metal organic framework toughened high-intensity fluorescent hydrogel according to claim 6, wherein the mass ratio of N-hydroxyethyl acrylamide to gelatin is 1: 0.16;

the molar ratio of the N-hydroxyethyl acrylamide to the photoinitiator 2959 is 1: 0.01.

8. A nano metal organic framework toughened high-strength fluorescent hydrogel, which is characterized by being prepared by the preparation method of any one of claims 1 to 7.

Technical Field

The invention relates to the field of high polymer material chemistry, in particular to a high-strength fluorescent hydrogel toughened by a nano metal organic framework and a preparation method thereof.

Background

The hydrogel is a high molecular polymer which contains hydrophilic groups and can swell and be insoluble in water and has a three-dimensional network structure formed by physical or chemical crosslinking, and is a special soft and wet material. Meanwhile, fluorescent materials have been widely used in various fields because of their excellent resistance to acids and bases, safety, and specific wavelength stimuli responsiveness. The fluorescent hydrogel combines the advantages of the hydrogel and has specific fluorescent response characteristics, has great application potential in the aspects of biomedicine, biosensing, tissue engineering and the like, and becomes a research hotspot in recent years.

Chinese patent CN111440332A discloses a preparation method of a fluorescent hydrogel composite material, and the novel composite material not only solves the problem of poor carbon point dispersibility, but also enables the compounded hydrogel to retain the excellent fluorescence characteristic of carbon points, and prepares the uniformly dispersed hydrogel with strong fluorescence response. However, the research on the existing fluorescent hydrogel is relatively few, the preparation process is complex, and most of the fluorescent hydrogels have weak mechanical properties, which severely limits the application of the fluorescent hydrogels in various fields.

Aiming at the problems, the prior art mainly improves the mechanical property of the fluorescent hydrogel by adjusting the ratio of raw materials and constructing a multiple network. For example, chinese patent CN107099004A discloses a high-intensity fluorescent hydrogel prepared by randomly mixing different polymeric materials and cross-linking agents in a ratio of 1:1 or any ratio to each other to construct a gel triple network. Although the method improves the mechanical property of the fluorescent hydrogel to a certain extent, the method has the disadvantages of large consumption of the cross-linking agent, complicated preparation process, and weak controllability of the experimental process, and is not suitable for wide application.

Therefore, it is an urgent technical problem to be solved by those skilled in the art to provide a high-strength fluorescent hydrogel toughened by a nano metal organic framework, which has significantly improved mechanical properties and can reduce the consumption of a cross-linking agent.

Disclosure of Invention

In view of the above, the invention provides a high-strength fluorescent hydrogel toughened by a nano metal-organic framework, which is synthesized by selecting a metal-organic framework with a zeolite-like structure and designing a ligand.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a high-strength fluorescent hydrogel toughened by a nano metal organic framework comprises the following steps:

(1) synthesizing a 2-vinyl-imidazole monomer;

(2) preparing V-ZIF-8(OFM @ V-ZIF-8) nanoparticles coated with Organic Fluorescent Molecules (OFM) by adopting 2-vinyl-imidazole monomers;

(3) preparing the high-intensity fluorescent hydrogel based on the OFM @ V-ZIF-8 nanoparticles.

Further, the specific operation method for synthesizing the 2-vinyl-imidazole monomer in the step (1) comprises the following steps:

1) dissolving methyl triphenyl phosphorus iodide and potassium tert-butoxide in an anhydrous tetrahydrofuran solvent at room temperature, and introducing nitrogen gas at 500-;

2) adding 2-imidazole formaldehyde into the solution obtained in the step 1), and continuously stirring at 500-800rpm for reaction for 24-36h at room temperature;

3) adding excessive ammonium chloride into the solution obtained in the step 2) to quench the reaction to obtain a reaction mixture;

4) extracting the reaction mixture with ethyl acetate, collecting an organic phase, washing the organic phase for 3-5 times by using saturated saline solution, drying the organic phase by using anhydrous magnesium sulfate, and rotationally evaporating the organic solvent at the temperature of 30-50 ℃ at the rotating speed of 20-40rpm to obtain a crude product;

5) purifying the crude product by using a silica gel column, collecting the product, and performing rotary evaporation at the temperature of 30-50 ℃ and the rpm of 20-40 to obtain the 2-vinyl-imidazole monomer.

Furthermore, the molar ratio of the methyl triphenyl phosphonium iodide to the potassium tert-butoxide in the step 1) is 1: 1.05;

the molar ratio of the methyl triphenyl phosphonium iodide to the 2-imidazole formaldehyde is 1: 0.5;

the silica gel column purification in the step 5) adopts petroleum ether: the mass ratio of ethyl acetate is 2: 3 as a detergent.

The beneficial effect of adopting the further scheme is that: in the scheme, the molar ratio of the methyl triphenyl phosphonium iodide to the potassium tert-butoxide is 1:1.05, and the molar ratio of the methyl triphenyl phosphonium iodide to the 2-imidazole formaldehyde is 1:0.5, so that the synthesized 2-vinyl-imidazole monomer has high yield and good purity and is suitable for subsequent application.

Preferably, the reactions in the steps 1), 2) and 3) are carried out at room temperature, so that the operation is easy and the control is convenient;

preferably, nitrogen is filled in the step 1) for stirring, so that radical oxidation is prevented, reaction is carried out under a protection state, and excessive waste of raw materials is avoided;

preferably, the step 2) is stirred at 500-;

preferably, the silica gel column in the step 5) is prepared by mixing the following components in a mass ratio of 2: 3 petroleum ether: ethyl acetate is used as a washing agent, and the crude product is further washed and purified, so that the purity of the prepared 2-vinyl-imidazole monomer is higher.

Further, the specific operation method for preparing the V-ZIF-8(OFM @ V-ZIF-8) nanoparticles coated with the Organic Fluorescent Molecules (OFM) by adopting the 2-vinyl-imidazole monomer in the step (2) comprises the following steps:

1) adding Zn (NO)₃)₂·6H₂O, organic fluorescent molecule, and 2-vinyl-imidazole monomer were dissolved in anhydrous methanol, respectively, and Zn (NO) was added at room temperature₃)₂·6H₂O methanolThe solution is quickly poured into a methanol solution of 2-vinyl-imidazole and organic fluorescent molecules, and is stirred for 1-2 hours at the room temperature at the speed of 500-800rpm to obtain a mixed solution;

2) centrifuging the mixed solution at 8000-;

3) re-dispersing the washed precipitate in methanol for storage for later use to obtain a nano OFM @ V-ZIF-8 nano-particle methanol dispersion liquid;

further, the organic fluorescent molecule, Zn (NO), in the above step 1)₃)₂·6H₂The molar ratio of O to 2-vinyl-imidazole monomer is 0.5:1: 5.

The beneficial effect of adopting the further scheme is that: in the scheme, a solvent synthesis method is adopted for synthesizing the V-ZIF-8 nano particles, so that the method is mild in condition, simple to operate and suitable for batch synthesis.

Preferably, the organic fluorescent molecule in step 1), Zn (NO)₃)₂·6H₂The molar ratio of the O to the 2-vinyl-imidazole monomer is 0.5:1:5, which is the optimal molar ratio for experiments, so that the obtained nanoparticles have higher yield and better fluorescence performance; the organic fluorescent small molecules in the step 1) are one or more of rhodamine B (RhB), Fluorescein (FL) or 7-Hydroxycoumarin (HC), and fluorescent nanoparticles with different emission wavelengths can be obtained through selection of the fluorescent molecules.

Preferably, step 2) repeats ultrasonic washing and centrifugation for 3-5 times, fully removes unreacted reactants, and improves the purity of the nanoparticles;

further, the specific operation method for preparing the high-intensity fluorescent hydrogel based on the OFM @ V-ZIF-8 nanoparticles in the step (4) comprises the following steps:

1) dissolving 10mL of OFM @ V-ZIF-8 nano particles in methanol to obtain an OFM @ V-ZIF-8 nano particle methanol dispersion, centrifuging the OFM @ V-ZIF-8 nano particle methanol dispersion at 8000rpm for 10-15min, removing supernatant, adding 10mL of deionized water to re-disperse the OFM @ V-ZIF-8 nano particles, and preparing an OFM @ V-ZIF-8 aqueous solution for later use;

2) adding an aqueous solution of N-hydroxyethyl acrylamide, gelatin, a photoinitiator 2959 and OFM @ V-ZIF-8 into a glass bottle filled with water, hermetically stirring, pumping air, filling nitrogen for 3 times, and continuously stirring in a water bath kettle at the temperature of 60-80 ℃ until all reactants are completely dissolved to obtain a pre-polymerization solution;

3) injecting the pre-polymerization solution into a glass mold through an injector, and naturally cooling to room temperature;

4) and transferring the mold to an 8W ultraviolet lamp for polymerization for 1-1.5h to obtain the high-strength fluorescent hydrogel toughened by the nano metal organic framework, and naming the high-strength fluorescent hydrogel as the OFM @ V-ZIF-8DN hydrogel.

Furthermore, the mass ratio of the N-hydroxyethyl acrylamide to the gelatin is 1: 0.16;

the molar ratio of N-hydroxyethyl acrylamide to photoinitiator 2959 was 1: 0.01.

The beneficial effect of adopting the further scheme is that: the hydrogel prepared by the scheme has good mechanical properties and good fluorescence properties, and provides a solution for the defect of weak mechanical properties of the existing fluorescent hydrogel.

Preferably, the mass ratio of the N-hydroxyethyl acrylamide to the gelatin in the step 2) is 1:0.16, and the molar ratio of the N-hydroxyethyl acrylamide to the photoinitiator I2959 is 1:0.01, so that the gel is easier to gel, and the experimental loss is reduced;

preferably, an 8W ultraviolet lamp is selected in the step 4), the formation of the gel network is accelerated by utilizing the energy of the ultraviolet, the polymerization time is 1-1.5h, so that the chains of the hydrogel network are fully contacted, the complete network is more stable, and the mechanical property is stronger.

The invention has the beneficial effects that: the invention provides a preparation method of high-strength fluorescent hydrogel, which adopts a ZIF-8 structure with a zeolite-like structure, obtains V-ZIF-8 nano particles by designing a ligand, can encapsulate organic fluorescent molecules, can introduce double bonds to play a role of a cross-linking agent, further synthesizes OFM @ V-ZIF-8 nano particles, and finally obtains the fluorescent hydrogel which not only has UV light stimulation responsiveness, but also has stronger mechanical properties, reduces the consumption of the cross-linking agent, and shows greater application potential in various fields

Drawings

FIG. 1 is a schematic diagram of the RhB @ V-ZIF-8/DN hydrogel synthesis of the present invention;

FIG. 2 is an infrared characterization chart of example 1;

FIG. 3 is a powder X-ray diffraction pattern of example 1

FIG. 4 is a graph comparing the mechanical properties of example 2 and comparative example 1

FIG. 5 is a graph comparing the mechanical properties of example 3 and comparative example 2

FIG. 6 is a graph comparing the mechanical properties of example 4 and comparative example 3

FIG. 7 is a graph of the luminescence of examples 2-8 under a 365nm UV lamp.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

A preparation method of a high-strength fluorescent hydrogel toughened by a nano metal organic framework comprises the following steps:

(1) synthesis of 2-vinyl-imidazole monomers

1) Dissolving methyltriphenylphosphorus iodide (8.4g,20.8mmol,2.0equiv) and potassium tert-butoxide (12.2g,21.8mmol,2.1equiv) in anhydrous tetrahydrofuran solvent at room temperature, and stirring with nitrogen at 500rpm for 30 min;

2) adding 2-imidazole formaldehyde (1.0g,10.4mmol,1.0equiv) into the solution obtained in the step 1), and stirring at room temperature at 500rpm for 24 hours to react;

3) adding excessive ammonium chloride into the solution obtained in the step 2) to quench the reaction to obtain a reaction mixture;

4) extracting the reaction mixture by using ethyl acetate, collecting an organic phase, washing the organic phase for 3 times by using saturated saline solution, drying the organic phase by using anhydrous magnesium sulfate, and rotatably evaporating the organic solvent to obtain a crude product;

5) purifying the crude product by using a silica gel column, and purifying by using petroleum ether: the mass ratio of ethyl acetate is 2: 3 as a washing agent, collecting the product, and performing rotary evaporation to obtain the 2-vinyl-imidazole monomer.

(2) Preparing V-ZIF-8(OFM @ V-ZIF-8) nanoparticles coated with an organic fluorescent molecule OFM by adopting a 2-vinyl-imidazole monomer:

1) adding Zn (NO)₃)₂·6H₂O (0.26g,0.875mmol), rhodamine B (0.21g,0.4375mmol) and 2-vinyl-imidazole monomer (0.34g,3.50mmol) were dissolved in anhydrous methanol, respectively, and Zn (NO) was added at room temperature₃)₂·6H₂Quickly pouring the O methanol solution into the methanol solution of 2-vinyl-imidazole, and stirring at the room temperature at the speed of 500rpm for 2 hours to obtain a mixed solution;

2) centrifuging the mixed solution at 10000rpm for 10min, removing supernatant, ultrasonically washing the precipitate with methanol, centrifuging, and repeatedly washing for 3 times;

3) re-dispersing the washed precipitate in methanol for storage for later use to obtain a RhB @ V-ZIF-8 nanoparticle methanol dispersion liquid;

4) replacing 0.21g of rhodamine B in the step 1) with 0.145g of fluorescein or 0.071g of 7-Hydroxycoumarin (HC) to respectively obtain FL @ V-ZIF-8 and HC @ V-ZIF-8 nanoparticles.

5) And drying the 2-vinyl-imidazole monomer, RhB @ V-ZIF-8, FL @ V-ZIF-8 and HC @ V-ZIF-8 nanoparticles, and performing structural characterization on the nanoparticles through infrared and X-ray single crystal diffraction.

EXAMPLE 2 preparation of Red-emitting 0.1 wt% RhB @ V-ZIF-8/DN hydrogel

1) Centrifuging the RhB @ V-ZIF-8 nanoparticle methanol dispersion liquid at 8000rpm for 15min, removing supernatant, adding 10ml of deionized water to redisperse RhB @ V-ZIF-8 nanoparticles, and preparing a RhB @ V-ZIF-8 aqueous solution for later use;

2) adding aqueous solutions of N-hydroxyethyl acrylamide (HEAA), gelatin (gelatin), a photoinitiator 2959 and RhB @ V-ZIF-8 into a glass bottle filled with water, wherein the mass percentages of the raw materials are 8% of gelatin, 50% of N-hydroxyethyl acrylamide and 2959% of photoinitiator (the addition amount is 1 mol% of the N-hydroxyethyl acrylamide), and the balance is RhB @ V-ZIF-8 aqueous solution, stirring in a sealed manner, pumping air, filling nitrogen, circulating for 3 times, and continuously stirring in a water bath kettle at 60 ℃ until all reactants are completely dissolved to obtain a pre-polymerization solution;

3) injecting the pre-polymerization solution into a glass mold through an injector, and naturally cooling to room temperature;

4) and transferring the mold to an 8W ultraviolet lamp for polymerization for 1h to obtain the RhB @ V-ZIF-8/DN hydrogel.

In the embodiment, the concentration of the RhB @ V-ZIF-8 nano particles is 0.1 wt% of the total mass of the prepolymerization solution, and the mechanical property of the hydrogel is tested through a tensile test. The RhB @ V-ZIF-8/DN hydrogel prepared in the example has the tensile strength of 2.4MPa and the tensile strain of 14.9 times.

EXAMPLE 3 preparation of Green 0.1 wt% FL @ V-ZIF-8/DN hydrogel

1) Centrifuging FL @ V-ZIF-8 nanoparticle methanol dispersion liquid at 10000rpm for 10min, removing supernatant, adding 10ml of deionized water to redisperse FL @ V-ZIF-8 nanoparticles, and preparing FL @ V-ZIF-8 aqueous solution for later use;

2) adding an aqueous solution of N-hydroxyethyl acrylamide (HEAA), gelatin (gelatin), a photoinitiator 2959 and FL @ V-ZIF-8 into a glass bottle filled with water, wherein the mass fractions of the raw materials are 8% of the gelatin, 50% of the N-hydroxyethyl acrylamide, 2959% of the photoinitiator (the addition amount is 1 mol% of the N-hydroxyethyl acrylamide), and the balance is the FL @ V-ZIF-8 aqueous solution, hermetically stirring, pumping air, filling nitrogen, circulating for 3 times, and continuously stirring in a water bath kettle at 60 ℃ until all reactants are completely dissolved to obtain a pre-polymerization solution;

3) injecting the pre-polymerization solution into a glass mold through an injector, and naturally cooling to room temperature;

4) and transferring the mold to an 8W ultraviolet lamp for polymerization for 1h to obtain FL @ V-ZIF-8/DN hydrogel.

In the embodiment, the concentration of the FL @ V-ZIF-8 nanoparticles is 0.1 wt% of the total mass of the prepolymerization solution, and the mechanical property of the hydrogel is tested through a tensile test. The tensile strength of HC @ V-ZIF-8/DN obtained in this example was 1.8MPa and the tensile strain was 12.4 times.

EXAMPLE 4 preparation of blue light 0.1 wt% HC @ V-ZIF-8/DN hydrogel

1) Centrifuging the HC @ V-ZIF-8 nanoparticle methanol dispersion liquid at 9000rpm for 12min, removing supernatant, adding 10ml of deionized water to redisperse HC @ V-ZIF-8 nanoparticles, and preparing an HC @ V-ZIF-8 aqueous solution for later use;

2) adding N-hydroxyethyl acrylamide (HEAA), gelatin (gelatin), a photoinitiator 2959 and an HC @ V-ZIF-8 aqueous solution into a glass bottle filled with water, wherein the mass fractions of the raw materials are 8% of the gelatin, 50% of the N-hydroxyethyl acrylamide, 2959% of the photoinitiator (the addition amount is 1 mol% of the N-hydroxyethyl acrylamide), and the balance is the FL @ V-ZIF-8 aqueous solution, hermetically stirring, pumping air, filling nitrogen, circulating for 3 times, and continuously stirring in a water bath kettle at 60 ℃ until all reactants are completely dissolved to obtain a pre-polymerization solution;

3) injecting the pre-polymerization solution into a glass mold through an injector, and naturally cooling to room temperature;

4) and transferring the mold to a 8W ultraviolet lamp for polymerization for 1h to obtain the HC @ V-ZIF-8/DN hydrogel.

In the embodiment, the concentration of the HC @ V-ZIF-8 nano particles is 0.1 wt% of the total mass of the prepolymerization solution, and the mechanical property of the hydrogel is tested through a tensile test. The HC @ V-ZIF-8/DN hydrogel prepared in the example has the tensile strength of 2.1MPa and the tensile strain of 12.8 times.

EXAMPLE 5 magenta RhB @ V-ZIF-8/HC @ V-ZIF-8/DN hydrogel was prepared

1) Centrifuging the RhB @ V-ZIF-8 and HC @ V-ZIF-8 nanoparticle methanol dispersion solutions for 13min at 8500rpm respectively, removing supernatant, adding 10ml of deionized water to redisperse RhB @ V-ZIF-8 and HC @ V-ZIF-8 nanoparticles respectively, and preparing RhB @ V-ZIF-8 and HC @ V-ZIF-8 aqueous solutions for later use;

2) adding an aqueous solution of N-hydroxyethyl acrylamide (HEAA), gelatin (gelatin), a photoinitiator 2959, RhB @ V-ZIF-8 and HC @ V-ZIF-8 into a glass bottle filled with water, wherein the mass fraction of each raw material is 8% of gelatin, 50% of N-hydroxyethyl acrylamide, 2959% of the photoinitiator (the addition is 1 mol% of N-hydroxyethyl acrylamide), and the balance is RhB @ V-ZIF-8 and HC @ V-ZIF-8 aqueous solution, stirring in a sealed manner, exhausting air and filling nitrogen for 3 times, and continuously stirring in a water bath kettle at 60 ℃ until all reactants are dissolved to obtain a pre-polymerization solution;

3) injecting the pre-polymerization solution into a glass mold through an injector, and naturally cooling to room temperature;

4) and (3) transferring the mold to an 8W ultraviolet lamp for polymerization for 1h to obtain the RhB @ V-ZIF-8/HC @ V-ZIF-8/DN hydrogel.

In the embodiment, the concentrations of RhB @ V-ZIF-8 and HC @ V-ZIF-8 nanoparticles are respectively 0.05 wt% of the total mass of the prepolymerization solution and 0.1 wt% of the total concentration of the nanoparticles.

EXAMPLE 6 preparation of yellow light RhB @ V-ZIF-8/FL @ V-ZIF-8/DN hydrogel

1) Centrifuging the RhB @ V-ZIF-8 and FL @ V-ZIF-8 nanoparticle methanol dispersion solutions for 11min at 9500rpm respectively, removing supernatant, adding 10ml of deionized water to redisperse RhB @ V-ZIF-8 and FL @ V-ZIF-8 nanoparticles respectively, and preparing RhB @ V-ZIF-8 and FL @ V-ZIF-8 aqueous solutions for later use;

2) adding an aqueous solution of N-hydroxyethyl acrylamide (HEAA), gelatin (gelatin), a photoinitiator 2959, RhB @ V-ZIF-8 and FL @ V-ZIF-8 into a glass bottle filled with water, wherein the mass fraction of each raw material is 8% of gelatin, 50% of N-hydroxyethyl acrylamide, 2959% of the photoinitiator (the addition is 1 mol% of N-hydroxyethyl acrylamide), and the balance is the aqueous solution of RhB @ V-ZIF-8 and FL @ V-ZIF-8, hermetically stirring and pumping-filling nitrogen for 3 times, and continuously stirring in a water bath kettle at 60 ℃ until all reactants are completely dissolved to obtain a pre-polymerization solution;

3) injecting the pre-polymerization solution into a glass mold through an injector, and naturally cooling to room temperature;

4) and transferring the mold to an 8W ultraviolet lamp for polymerization for 1h to obtain the RhB @ V-ZIF-8/FL @ V-ZIF-8/DN hydrogel.

In the embodiment, the concentrations of the RhB @ V-ZIF-8 nanoparticles and the FL @ V-ZIF-8 nanoparticles are respectively 0.05 wt% of the total mass of the prepolymerization solution and 0.1 wt% of the total concentration of the nanoparticles.

EXAMPLE 7 preparation of Qingguang FL @ V-ZIF-8/HC @ V-ZIF-8/DN hydrogel

1) Respectively 8800rpm of FL @ V-ZIF-8 and HC @ V-ZIF-8 nanoparticle methanol dispersion solutions for 14min, removing supernatant, adding 10ml of deionized water to respectively re-disperse FL @ V-ZIF-8 and HC @ V-ZIF-8 nanoparticles, and preparing FL @ V-ZIF-8 and HC @ V-ZIF-8 aqueous solutions for later use;

2) adding an aqueous solution of N-hydroxyethyl acrylamide (HEAA), gelatin (gelatin), a photoinitiator 2959, FL @ V-ZIF-8 and HC @ V-ZIF-8 into a glass bottle filled with water, wherein the mass fraction of each raw material is 8% of the gelatin, 50% of the N-hydroxyethyl acrylamide, and 2959% of the photoinitiator (the addition amount is 1 mol% of the N-hydroxyethyl acrylamide), and the balance is the aqueous solution of FL @ V-ZIF-8 and HC @ V-ZIF-8, hermetically stirring and pumping-filling nitrogen for 3 times, and continuously stirring in a water bath kettle at 60 ℃ until all reactants are completely dissolved to obtain a pre-polymerization solution;

3) injecting the pre-polymerization solution into a glass mold through an injector, and naturally cooling to room temperature;

4) and transferring the mold to an 8W ultraviolet lamp for polymerization for 1h to obtain the FL @ V-ZIF-8/HC @ V-ZIF-8/DN hydrogel.

In the embodiment, the concentration of FL @ V-ZIF-8/HC @ V-ZIF-8 nanoparticles is 0.05 wt% of the total mass of the prepolymerization solution, and the total concentration of nanoparticles is 0.1 wt%.

EXAMPLE 8 preparation of white RhB @ V-ZIF-8/FL @ V-ZIF-8/HC @ V-ZIF-8/DN hydrogel

1) Centrifuging the RhB @ V-ZIF-8, FL @ V-ZIF-8 and HC @ V-ZIF-8 nanoparticle methanol dispersions for 13min at 9200rpm respectively, removing supernatant, adding 10ml of deionized water to re-disperse the RhB @ V-ZIF-8, FL @ V-ZIF-8 and HC @ V-ZIF-8 nanoparticles respectively to prepare RhB @ V-ZIF-8, FL @ V-ZIF-8 and HC @ V-ZIF-8 aqueous solutions for later use;

2) adding aqueous solutions of N-hydroxyethyl acrylamide (HEAA), gelatin (gelatin), a photoinitiator 2959, RhB @ V-ZIF-8, FL @ V-ZIF-8 and HC @ V-ZIF-8 into a glass bottle filled with water, wherein the mass fractions of the raw materials are gelatin 8%, N-hydroxyethyl acrylamide 50%, and a photoinitiator 2959 (the addition amount is N-hydroxyethyl acrylamide 1 mol%), and the balance is RhB @ V-ZIF-8, FL @ V-ZIF-8 and HC @ V-ZIF-8 aqueous solutions, performing sealed stirring and air-suction-nitrogen filling circulation for 3 times, and continuously stirring in a water bath kettle at 60 ℃ until all reactants are dissolved to obtain a pre-polymerization liquid;

3) injecting the pre-polymerization solution into a glass mold through an injector, and naturally cooling to room temperature;

4) and (3) transferring the mold to an 8W ultraviolet lamp for polymerization for 1h to obtain RhB @ V-ZIF-8/FL @ V-ZIF-8/HC @ V-ZIF-8/DN hydrogel.

In the embodiment, the concentrations of RhB @ V-ZIF-8, FL @ V-ZIF-8 and HC @ V-ZIF-8 nanoparticles are respectively 0.033 wt% of the total mass of the prepolymerization solution and 0.1 wt% of the total concentration of the nanoparticles.

Comparative example 1 preparation of RhB/DN hydrogel

1) Adding aqueous solutions of N-hydroxyethyl acrylamide (HEAA), gelatin (gelatin), photoinitiator 2959 and rhodamine B (RhB) into a glass bottle filled with water, wherein the mass fractions of the raw materials are 8% of gelatin, 50% of N-hydroxyethyl acrylamide, 2959% of photoinitiator (the addition amount is 1 mol% of N-hydroxyethyl acrylamide), and the balance of RhB aqueous solution, hermetically stirring, pumping air, and charging nitrogen for 3 times, and continuously stirring in a water bath kettle at 60 ℃ until all reactants are completely dissolved to obtain a pre-polymerization solution;

3) injecting the pre-polymerization solution into a glass mold through an injector, and naturally cooling to room temperature;

4) and transferring the mold to a 8W ultraviolet lamp for polymerization for 1h to obtain the RhB/DN hydrogel.

In this example, the RhB concentration is 0.1 wt% of the total mass of the prepolymer solution.

The RhB/DN hydrogel prepared by the method has the tensile strength of 0.55MPa and the tensile strain of 7.37 times.

Comparative example 2 preparation of FL/DN hydrogel

1) Adding N-hydroxyethyl acrylamide (HEAA), gelatin (gelatin), a photoinitiator 2959 and a Fluorescein (FL) aqueous solution into a glass bottle filled with water, wherein the mass fractions of the raw materials are 8% of gelatin, 50% of N-hydroxyethyl acrylamide, 2959% of the photoinitiator (the addition amount is 1 mol% of N-hydroxyethyl acrylamide) and the balance of the FL aqueous solution, sealing, stirring, pumping air, filling nitrogen, circulating for 3 times, and continuously stirring in a water bath kettle at 60 ℃ until all reactants are dissolved to obtain a pre-polymerization solution;

3) injecting the pre-polymerization solution into a glass mold through an injector, and naturally cooling to room temperature;

4) and transferring the mold to a 8W ultraviolet lamp for polymerization for 1h to obtain the FL/DN hydrogel.

The FL concentration in this comparative example was 0.1 wt% of the total mass of the prepolymerization solution.

The tensile strength of the FL/DN hydrogel prepared by the comparative example is 0.61MPa, and the tensile strain is 14.7 times.

Comparative example 3 preparation of HC/DN hydrogel

1) Adding aqueous solutions of N-hydroxyethyl acrylamide (HEAA), gelatin (gelatin), photoinitiator 2959 and 7-Hydroxycoumarin (HC) into a glass bottle filled with water, wherein the mass fractions of the raw materials comprise 8% of gelatin, 50% of N-hydroxyethyl acrylamide, 2959% of photoinitiator (the addition amount is 1 mol% of N-hydroxyethyl acrylamide) and the balance of HC aqueous solution, sealing, stirring, pumping air, filling nitrogen, circulating for 3 times, and continuously stirring in a water bath kettle at 60 ℃ until all reactants are dissolved to obtain a pre-polymerization solution;

3) injecting the pre-polymerization solution into a glass mold through an injector, and naturally cooling to room temperature;

4) and transferring the mould to a 8W ultraviolet lamp for polymerization for 1h to obtain the HC/DN hydrogel.

The HC concentration in this comparative example was 0.1 wt% of the total mass of the prepolymerization solution.

The HC/DN hydrogel prepared by the comparative example has the tensile strength of 1.26MPa and the tensile strain of 12.6 times.

The preparation method is a specific embodiment of the invention, and has the advantages of simple preparation process and strong experimental controllability. As shown in FIGS. 4-6, the fracture stress of the OFM @ V-ZIF-8/DN complex gel is much greater than that of the hydrogel directly doped with the fluorescent dye. The result shows that the mechanical property of the fluorescent hydrogel can be effectively improved by introducing the double-network gel after the V-ZIF-8 nano particles adsorb fluorescent molecules. Meanwhile, the high-intensity fluorescent hydrogel prepared by the method has specific response under the stimulation of UV light, and has wide application prospect in the fields of biosensing and the like.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.