Efficient active oxygen free radical generation method based on silver sulfide quantum dots and application of efficient active oxygen free radical generation method

Abstract

The invention discloses an efficient active oxygen free radical generation method based on silver sulfide quantum dots and application of the efficient active oxygen free radical generation method, and belongs to the technical field of nano catalysis. According to the method, Ag2S quantum dots are added into water or an H2O2 aqueous solution to be mixed and react, active oxygen free radicals OH are obtained, and the principle of the method is as follows: Ag2S QDs and the aqueous solution form a solid-liquid interface, after interface contact is enhanced through vortex or ultrasound, water molecules and hydroxyl ions are induced to lose electrons on the interface to form OH, and the OH is separated from the solid-liquid interface. Meanwhile, Ag2S QDs capture electrons to form a negatively-charged excited state (Ag2S), H2O2 serves as a reaction substrate, electrons are obtained from the negatively-charged Ag2S, and OH is further generated. The limitation of a traditional catalytic system is broken through, efficient generation of active oxygen under a solid-liquid interface is achieved, the rapid degradation capacity on organic pollutants (such as dye and pesticide) is shown, and the potential application value in medicine preparation is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nanocatalysis, and particularly relates to a high-efficiency active oxygen free radical generation method based on silver sulfide quantum dots (Ag2S QDs) and application thereof. BACKGROUND

[0002] Hydroxyl radical (·OH) is a free radical with extremely strong oxidation ability, and is commonly applied to multiple fields such as organic pollutant degradation, water purification, antibiosis and tumor treatment. Traditional ·OH generation methods include photocatalysis (such as TiO2 ultraviolet irradiation), electrocatalysis, Fenton reaction, thermal activation and the like, however, these methods generally have the following problems: dependence on external energy input (such as light, electricity or heat), harsh requirements on environmental conditions, complex reaction system or poor stability of catalysts, which limits the widespread application thereof in actual scenes. In recent years, contact electrocatalysis (CEC) as a new emerging catalytic strategy has gradually attracted attention. This mechanism utilizes the electron transfer occurring in the contact electrification process of two-phase materials to drive the interface redox reaction, and can realize the generation of free radicals without additional energy input. However, the current researches on the CEC system are mostly concentrated on polymer materials or macroscopic semiconductor particles, and the feasibility thereof has not been systematically verified in nanoscale materials, especially quantum dot systems.

[0003] As a near-infrared two-region (NIR-II) fluorescent probe, Ag2S quantum dots have attracted much attention in the biomedical field in recent years due to their excellent biocompatibility and deep tissue penetration ability. Recent studies have shown that under near-infrared light excitation, Ag2S quantum dots can realize photocatalytic activity through electron-hole pair separation, and the conduction band position thereof is negative enough to reduce oxygen to generate superoxide free radical (·O2 - ), and the valence band position can directly oxidize water or organic matter to produce hydroxyl radical (·OH). However, the CEC catalytic activity of Ag2S quantum dots has not been reported. The application first utilizes the interface charge interaction between Ag2S quantum dots and water to spontaneously generate ·OH free radicals, and further combines H2O2 to enhance the catalytic efficiency, thereby providing a new solution for developing new self-powered pollution degradation and biological intervention technologies. SUMMARY

[0004] The application aims to tap the catalytic potential of Ag2S quantum dots, and provides a high-efficiency active oxygen free radical generation method based on silver sulfide quantum dots and application thereof. The CEC catalytic reaction system composed of Ag2S quantum dots and hydrogen peroxide (H2O2) aqueous solution is utilized to generate ·OH under vortex or ultrasonic conditions, and the catalytic reaction mechanism is as follows: Figure 1As shown: when the "solid-liquid" interface contact between Ag2S quantum dots and aqueous solution occurs, electron transfer occurs on the interface, Ag2S QDs capture electrons from H2O or OH - to form Ag2S , while H2O or OH - loses electrons to generate •OH; subsequently, H2O2 in the aqueous solution collides with the negatively charged Ag2S to capture electrons from Ag2S to generate •OH again. The present application provides a new method for generating active oxygen free radicals, and for the first time, the ability of Ag2S to catalyze water and H2O2 to generate •OH is discovered. The present application will expand the new application of Ag2S quantum dots in the field of biomedicine, and provide important scientific basis for developing new catalytic strategies, and has important theoretical and application value.

[0005] The object of the present application is achieved by the following technical scheme: An efficient active oxygen free radical generation method based on silver sulfide quantum dots, comprising the following steps: adding Ag2S quantum dots into water to form a reaction system A for reaction, or adding Ag2S quantum dots into an aqueous H2O2 solution to form a reaction system B for reaction, to generate active oxygen free radicals •OH.

[0006] Further, in the reaction system A or the reaction system B, the concentration of Ag2S quantum dots is preferably 0.05-0.3 mg / mL; in the reaction system B, the concentration of H2O2 is preferably 100-900 mM.

[0007] Further, the reaction of the reaction system A or the reaction system B is preferably carried out under vortex or ultrasonic conditions, and the reaction temperature is preferably room temperature. Vortex or ultrasonic is used to promote the "solid-liquid" interface contact between Ag2S quantum dots and aqueous solution, and electron transfer is caused at the interface, and electrons can be transferred from water and hydroxyl ions to Ag2S to generate •OH, and Ag2S carries a negative charge (Ag2S ). Subsequently, H2O2 can obtain electrons from the negatively charged Ag2S (Ag2S ) to generate •OH, realizing the process of Ag2S catalyzing H2O2 to generate •OH.

[0008] The efficient active oxygen free radical generation method based on silver sulfide quantum dots is applied in the field of environmental pollutant degradation. The pollutants can react with active oxygen to be degraded, including methylene blue, terephthalic acid, etc.

[0009] A method for degrading environmental pollutants, comprising the following steps: adding Ag2S quantum dots to water containing pollutants, and carrying out vortex or ultrasonic treatment.

[0010] A method for degrading environmental pollutants, comprising the following steps: adding Ag2S quantum dots, H2O2 or a substance capable of generating H2O2 into water containing pollutants, and performing vortex or ultrasonic treatment. The substance capable of generating H2O2 includes an enzyme capable of generating H2O2 (for example, glucose oxidase GOD), a substance having an enzyme-like (similar to the enzyme capable of generating H2O2) activity (for example, nano-enzyme), and the like.

[0011] Application of Ag2S quantum dots and H2O2 or a substance capable of generating H2O2 in the field of degradation of environmental pollutants or in the preparation of an environmental pollutant degradation agent.

[0012] Application of Ag2S quantum dots and H2O2 or a substance capable of generating H2O2 in the preparation of a drug or a medical catalytic material. The indications of the drug are diseases capable of being treated by active oxygen, including cancer, infectious diseases, autoimmune diseases, neurodegenerative diseases, cardiovascular diseases, and the like, the cancer includes breast cancer, liver cancer, lung cancer, skin cancer, and the like, the infectious diseases include bacterial inflammation, fungal infection, viral infection, and the like, the autoimmune diseases include rheumatoid arthritis, multiple sclerosis, and the like, the neurodegenerative diseases include Alzheimer's disease, Parkinson's disease, and the like, and the cardiovascular diseases include ischemic heart disease, peripheral arterial disease, and the like. The substance capable of generating H2O2 includes an enzyme capable of generating H2O2 (for example, glucose oxidase GOD), a substance having an enzyme-like (similar to the enzyme capable of generating H2O2) activity (for example, nano-enzyme), a drug for promoting the generation of H2O2 in the body, and the like.

[0013] An environmental pollutant degradation agent or a drug or a medical catalytic material, comprising Ag2S quantum dots, and H2O2 or a substance capable of generating H2O2.

[0014] The present application breaks through the limitation of the traditional catalytic system, realizes the efficient generation of active oxygen at the solid-liquid interface, exhibits the rapid degradation ability of Ag2S QDs to organic pollutants (such as dyes and pesticides), and has potential application value in the preparation of drugs. The present application first discloses the special mechanism of Ag2S QDs in catalyzing water and H2O2 to generate •OH at the solid-liquid interface, provides an innovative idea for developing a new type of liquid phase catalytic system, and has significant scientific significance and practical application prospect.

[0015] The present application has the following beneficial effects: (1) The present application provides an efficient active oxygen radical generation method based on silver sulfide quantum dots and application thereof, and a new mechanism of Ag2S quantum dots in catalyzing H2O and H2O2 to generate •OH is found.

[0016] (2) The preparation method of Ag2S quantum dots is simple, and the catalytic performance is stable.

[0017] (3) Ag2S quantum dots can be applied to the fields of environmental pollutant degradation and disease treatment.

[0018] (4) This invention provides important scientific basis for the development of novel catalytic strategies and has important theoretical and application value. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the mechanism of the reactive oxygen free radical generation method based on silver sulfide quantum dots of the present invention.

[0020] Figure 2 This is a flowchart of the preparation process of Ag2S quantum dots.

[0021] Figure 3 This is a transmission electron microscope image of Ag2S quantum dots.

[0022] Figure 4 These are the DMPO-•OH electron spin resonance spectra of Ag2S-H2O and Ag2S-H2O2 after vortex (a) or ultrasonic (b) treatment.

[0023] Figure 5 The UV-Vis absorption spectra of methylene blue solutions of Ag2S-H2O and Ag2S-H2O2 after vortexing (a) or sonication (b) are shown. Detailed Implementation

[0024] The present invention is further described below through the following non-limiting embodiments. It should be understood that these embodiments are only some preferred technical solutions of the present invention, and the protection scope of the present invention is not limited to these embodiments.

[0025] Example 1: Preparation and Characterization of Ag₂S Quantum Dots Preparation method: The preparation process of Ag2S quantum dots is as follows Figure 2As shown, 10 mL of ethylene glycol was added to a 25 mL three-necked round bottom flask and degassed for 30 minutes. After degassing, the ethylene glycol was heated to 110°C, and then 100 μL of mercaptopropionic acid and 8.45 mg of silver nitrate (0.05 mmol) were rapidly added to the reaction system. The temperature was then increased, and when the temperature reached 145-150°C, the reaction was timed. The reaction was generally terminated after 90 minutes, and the product was purified by centrifugation. The emission wavelength was about 1100 nm, and the reaction time and centrifugation were continuously monitored. The size of the product increased with the reaction time, and the emission was continuously red-shifted. After the temperature was increased to 145°C, the state of the mixture began to change, from an initial white flocculent turbidity to a milky white liquid, and then to yellow, brown, and finally to dark brown. After the reaction was stopped, the supernatant was discarded by centrifugation, and the precipitate was collected as larger size Ag2S quantum dots. Finally, the collected Ag2S quantum dots were washed three times using an ultrafiltration centrifuge tube, at a centrifuge speed of 2500 rpm for 60 minutes each time. After the three washes, the Ag2S quantum dots were dissolved in pure water and used in the following examples.

[0026] Characterization: Transmission electron microscopy tests showed that the Ag2S QDs prepared in this example were nanoparticles with a particle size of 5.43 nm (standard deviation of 0.62 nm). Figure 3 ).

[0027] Example 2 Performance evaluation of Ag2S QDs for catalyzing H2O2 to produce reactive oxygen free radicals Ag2S QDs (0.3 mg / mL) were added to an aqueous solution containing H2O2 (100 mM) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO, 10 mM), or an aqueous solution containing DMPO (10 mM). The solution was then treated by vortexing (700 rpm) or ultrasonication (30 kHz, 2.0 W / cm 2 ) for 30 minutes. The ESR spectrum of the mixed solution was determined by an electron paramagnetic resonance (ESR) spectrometer (Bruker magnettech ESR5000, Germany). ESR tests showed that Ag2S QDs could generate •OH (hydroxyl radical) in an aqueous solution with or without H2O2, by vortexing or ultrasonication. Figure 4

[0028] Example 3 Use of Ag2S QDs for degradation of environmental pollutants methylene blue (MB) ​Ag2S QDs were added to aqueous solution containing H2O2 and MB, and the UV-Vis absorption spectra of MB were recorded after ultrasonic or vortex treatment. The specific experimental process is as follows: Ag2S QDs (0.3 mg / mL) were added to aqueous solution containing H2O2 (100 mM) and MB (10 μg / mL), or aqueous solution containing MB (10 μg / mL), and the total volume was 3 mL. The solution was treated by vortex (700 rpm) or ultrasonic (30 kHz, 2.0 W / cm2) for 30 min. Subsequently, the mixed solution was subjected to ultrafiltration centrifugation (10000 rpm). Finally, the absorbance change of MB was determined by UV-Vis absorption spectra. The results are shown in 2 Fig. 2. Figure 5 Under the treatment of vortex for 30 min, MB was degraded due to the generation of •OH, and the absorbance at 664 nm decreased. The degradation of MB+Ag2S QDs in H2O2 solution was more obvious than that of MB+Ag2S QDs in water solution, which proved the ability of Ag2S QDs to catalyze H2O and H2O2 to generate reactive oxygen species. Compared with vortex, the degradation of MB+Ag2S QDs was more obvious under the condition of ultrasonic for 30 min.

[0029] The above merely describes the preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any modification, equivalent replacement and improvement made by any person skilled in the art within the technical scope disclosed by the present application should be included in the scope of protection of the present application.

Claims

1. A method for generating reactive oxygen radical species based on silver sulfide quantum dots, characterized by, The method comprises the following steps: The Ag2S quantum dots are added into water to form a reaction system A, or the Ag2S quantum dots are added into an aqueous H2O2 solution to form a reaction system B, so that active oxygen free radicals •OH are generated.

2. The silver sulfide quantum dot-based reactive oxygen radical generation method according to claim 1, characterized by: The concentration of the Ag2S quantum dots in the reaction system A or the reaction system B is 0.05-0.3 mg / mL.

3. The silver sulfide quantum dot-based reactive oxygen radical generation method according to claim 1, characterized by: The concentration of the H2O2 in the reaction system B is 100-900 mM.

4. The silver sulfide quantum dot-based reactive oxygen radical generation method according to claim 1, characterized by: The reaction is carried out under vortex or ultrasonic conditions.

5. Use of the method for the generation of reactive oxygen radicals based on silver sulfide quantum dots according to any one of claims 1 to 4 in the field of environmental pollutant degradation, characterized in that: The pollutants can be degraded by reacting with active oxygen.

6. A method of degrading an environmental pollutant, characterized by, The method comprises the following steps: The Ag2S quantum dots are added into water containing pollutants, and vortex or ultrasonic treatment is carried out; or the Ag2S quantum dots, H2O2 or a substance capable of generating H2O2 are added into water containing pollutants, and vortex or ultrasonic treatment is carried out.

7. Use of Ag2S quantum dots and H2O2 or a substance capable of generating H2O2 in the field of environmental pollutant degradation or in the preparation of an environmental pollutant degradation agent, characterized in that: The pollutants can be degraded by reacting with active oxygen.

8. Use of Ag2S quantum dots and H2O2 or a substance capable of generating H2O2 for the preparation of a pharmaceutical or medical catalytic material, characterized in that: The drug is indicated for diseases that can be treated by active oxygen.

9. Use according to claim 8, characterized in that: The diseases that can be treated by active oxygen include cancer, infectious diseases, autoimmune diseases, neurodegenerative diseases and cardiovascular diseases.

10. An environmental pollutant degrading agent or a pharmaceutical or medical catalytic material, characterized by: The drug comprises Ag2S quantum dots, H2O2 or a substance capable of generating H2O2.

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