Polystyrene nano-particles, preparation method thereof and application of polystyrene nano-particles in quantitative detection of nano-plastic concentration in living body

Abstract

The invention discloses a preparation method of polystyrene nanoparticles with a magnetic imaging function, which comprises the following steps: (1) preparation of a core: weighing ferric trichloride hexahydrate, sodium acetate and polyethylene glycol, putting into a high-pressure kettle, respectively reacting for different time lengths under different temperature systems, washing the obtained mixed solution with absolute ethyl alcohol under the action of an external magnetic field, and drying; (2) preparation of a shell: preparing 13C / 14C isotope labeled polystyrene nanoparticles by using a 13C / 14C isotope labeled styrene monomer in a dispersion polymerization manner; and (3) preparation of a core-shell structure: mixing ferrite particles, polystyrene nanoparticles, cuprous chloride, 4, 4 '-dinonyl-2, 2'-dipyridyl and xylene, and stirring at 130 DEG C for 24 hours. The polystyrene nano-particles obtained by the invention have important significance for exploring the transfer process of micro-plastics in organisms and studying the toxic effect of the micro-plastics.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical synthesis, in particular to polystyrene nanoparticles and a preparation method thereof, and an application thereof in quantitatively detecting the concentration of nanoplastics in a living body. Background Art

[0002] With the widespread use of plastic products, the range of environmental issues they cause has gradually attracted attention. When plastic products degrade in the environment to a particle size less than 1 nm, they are called nanoplastics. Because nanoplastics are small, highly toxic, and difficult to detect, they have gradually attracted research. Nanoplastics can enter organisms and the human body through inhalation, ingestion, and surface contact. Because they can adsorb other pollutants in the environment, resulting in compound toxicity, they have become one of the new pollutants of the new century. Because the spatial resolution of conventional Fourier transform infrared spectroscopy and Raman spectroscopy is limited by the diffraction limit of light, their detection limits are 10 and 300 nm, respectively. For most nanoplastics, these two methods are not applicable, necessitating the use of new methods. Current methods for detecting nanoplastics include: liquid extraction or depolymerization of insoluble polymers to determine polymer mass, cascade filtration or field-flow fractionation (FFF) to determine nanoplastic size fractionation, mass-based nanoplastic analysis using pyrolysis gas chromatography / mass spectrometry (Py-GC / MS) and thermal desorption proton transfer reaction mass spectrometry (TD-PTR / MS), non-destructive spectral analysis, surface-enhanced Raman scattering, and a combination of scanning electron microscopy and Raman spectroscopy. However, most current detection methods require fluorescent modification of the pollutants to be detected, and the fluorescent labels of fluorescently labeled nanoplastics are easily shed when they accumulate in organisms. In addition, some organisms have autofluorescence, which affects the distribution of pollutants in the organism.

[0003] In response to the problems existing in current fluorescent labeling and inspired by nuclear magnetic resonance technology, this patent aims to invent a method to determine the distribution of nanoplastics in the body by detecting metal materials in the body, and to calculate the total amount of microplastics ingested into the body through isotope-labeled styrene. Summary of the Invention

[0004] In order to at least solve or partially solve the above problems, a polystyrene nanoparticle and a preparation method thereof and an application thereof in quantitatively detecting the concentration of nanoplastics in a living body are provided.

[0005] In order to achieve the above object, the present invention provides the following technical solutions: The present invention provides a method for preparing polystyrene nanoparticles, comprising the following steps: a: Purification of styrene monomer; b: Preparation of Fe3O4 nanoparticles; c: Activated Fe3O4 nanoparticles are weighed and dissolved in an isotope styrene monomer, cuprous chloride and 4,4'-dinonyl-2,2'-bipyridine are dissolved in xylene, and then the Fe3O4 nanoparticle / isotope styrene monomer mixture is added; under a protective gas state, polystyrene nanoparticles are obtained; the particle size of the Fe3O4 nanoparticles is reduced to less than 5 nm.

[0006] As a preferred technical solution of the present invention, the steps of purifying the styrene monomer are: using a vacuum distillation method to remove the main polymerization inhibitor in styrene, namely hydroquinone; then washing it with NaOH, and then washing it with water until the water is detected to be neutral; drying it with anhydrous magnesium sulfate overnight, and then performing vacuum distillation, and continuously extracting it with a water pump.

[0007] As a preferred technical solution of the present invention, the steps of preparing Fe3O4 nanoparticles are: weighing ferric chloride hexahydrate into a beaker, weighing a certain amount of ethylene glycol and adding it to the beaker, and stirring at room temperature until the ferric chloride hexahydrate is completely dissolved and maintaining the stirring state; weighing a certain amount of sodium acetate and polyethylene glycol and adding them to the above mixed system, keeping the solution vigorously stirred for 30 minutes, then sealing it in a stainless steel autoclave with a polytetrafluoroethylene liner, and reacting it at 100°C for 1 hour, then heating it to 200°C and continuing the reaction at this temperature; the solution after the reaction is naturally cooled to room temperature, and is transferred to a beaker of appropriate capacity, and the Fe3O4 nanoparticles therein are separated under the action of an external magnetic field, and washed several times with anhydrous ethanol, and finally vacuum frozen.

[0008] As a preferred technical solution of the present invention, the specific steps of step c are as follows: C1: Activation of Fe3O4 nanoparticles: The ferrite nanoparticles were activated by stirring in a 1.0 M 3-chloropropionic acid solution overnight, and the pH was adjusted with a NaOH solution. After activation, the Fe3O4 nanoparticles were recovered using a magnet and washed several times with deionized water to remove excess 3-chloropropionic acid solution. The activated Fe3O4 nanoparticles were freeze-dried. C2: Preparation of isotope styrene monomer: 13 C / 14 C-labeled styrene and commercial styrene were mixed evenly under the protection of nitrogen; C3: Reaction system: Weigh the Fe3O4 nanoparticles activated in step C1 into the isotope styrene monomer, dissolve cuprous chloride and 4,4'-dinonyl-2,2'-bipyridine in xylene, and then add the Fe3O4 nanoparticles / isotope styrene monomer mixture; C4: Preparation of isotope-labeled shell: Under nitrogen, the reaction system in step C3 was stirred at 130°C. After the reaction was stopped, it was naturally cooled at room temperature. The nanoparticles were recovered using a magnet, washed several times with toluene, and finally air-dried in a fume hood.

[0009] The present invention provides polystyrene nanoparticles prepared by the preparation method described in the above technical solution, wherein the particle size of ferrite in the polystyrene nanoparticles is reduced to below 5 nm.

[0010] The present invention provides a method for quantitatively detecting the concentration of nanoplastics in fish, comprising the following steps: using a 13 Feeding fish with C-labeled polystyrene nanoplastic feed to obtain poisoned fish; the polystyrene nanoplastic is the polystyrene nanoplastic described in the above technical solution; Prepare samples of fish tissues infected with poison; A control experiment was set up, where fish were fed with feed that did not contain nanoplastics. Using the controlled variable method, only the fish feed was kept different, and tissue samples were also prepared from the fish in the control group. Stable isotope mass spectrometry was used to determine the concentrations of the infected fish, control fish, and 13 C-labeled polystyrene nanoplastics 13 The mass content of C.

[0011] Compared with the prior art, the present invention has the following beneficial effects: The present invention can accurately and quantitatively detect the concentration of nanoplastics in organisms. The method provided by the present invention has high detection accuracy and sensitivity, and is of great significance for exploring the transport process of microplastics in organisms and studying the toxic effects of microplastics. DETAILED DESCRIPTION

[0012] The preferred embodiments of the present invention are described below. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0013] Furthermore, if detailed description of known art is not necessary to illustrate the characteristics of the present invention, it will be omitted.

[0014] The present invention provides a method for preparing polystyrene nanoparticles, comprising the following steps: (1) Purification of styrene monomer (1) Using vacuum distillation to remove the main inhibitor of styrene, hydroquinone; (2) Wash it with NaOH 1-2 times, and then wash it with water 1-2 times until the water is detected to be neutral; (3) Dry with anhydrous magnesium sulfate overnight, then perform vacuum distillation and continuously extract with a water pump.

[0015] (2) Preparation of core (1) Weigh ferric chloride hexahydrate into a beaker, weigh a certain amount of ethylene glycol and add it to the beaker, and stir at room temperature until the ferric chloride hexahydrate is completely dissolved and keep stirring; (2) Weigh a certain amount of sodium acetate and polyethylene glycol and add them to the above mixed system. Keep the solution vigorously stirred for 30 minutes and then seal it in a stainless steel autoclave with a polytetrafluoroethylene liner. React at 100°C for 1 hour, then raise the temperature to 200°C and continue the reaction at this temperature for 7-9 hours. (3) The solution after the reaction is naturally cooled to room temperature and transferred to a beaker of appropriate capacity. The Fe3O4 nanoparticles are separated under the action of an external magnetic field, washed several times with anhydrous ethanol, and finally vacuum-frozen for 5-7 hours.

[0016] (3) Shell preparation (1) Activation of Fe3O4 nanoparticles: The ferrite nanoparticles were stirred and activated in a 1.0 M 3-chloropropionic acid solution overnight, and the pH was adjusted with a NaOH solution. After activation, the Fe3O4 nanoparticles were recovered using a magnet and washed several times with deionized water to remove excess 3-chloropropionic acid solution. The activated Fe3O4 nanoparticles were freeze-dried. (2) Preparation of isotope styrene monomer: 13 C / 14 C-labeled styrene and commercial styrene were mixed evenly under the protection of nitrogen; (3) Reaction system: Weigh the activated Fe3O4 nanoparticles in (1) into the isotope styrene monomer, dissolve cuprous chloride and 4,4'-dinonyl-2,2'-bipyridine in xylene, and then add the Fe3O4 nanoparticles / isotope styrene monomer mixed system.

[0017] (4) Preparation of isotope-labeled shell: The reaction system (3) was stirred at 130°C under nitrogen. After the reaction was stopped, it was naturally cooled at room temperature. The nanoparticles were recovered using a magnet, washed several times with toluene, and finally air-dried in a fume hood.

[0018] Example 1 A method for preparing polystyrene nanoparticles comprises the following steps: Purification of styrene monomer (1) First, wash the styrene monomer with 8%-12% NaOH 1-2 times, and then wash it with water 1-2 times until the water is detected to be neutral; (2) Dry overnight with anhydrous magnesium sulfate, filter it and then distill it under reduced pressure, and extract it with a water pump at 65~75℃.

[0019] (2) Preparation of core (1) Weigh 1.35 g (5 mmol) of ferric chloride hexahydrate into a 100 mL beaker, and add 40 mL of ethylene glycol to the beaker. Stir at room temperature until the ferric chloride hexahydrate is completely dissolved and keep stirring. (2) 3.6 g of sodium acetate and 1.0 g of polyethylene glycol were added to the mixture of (1). The solution was stirred vigorously for 30 min and then sealed in a stainless steel autoclave (50 mL) lined with polytetrafluoroethylene. The reaction was carried out at 100 °C for 1 h, and then the temperature was raised to 200 °C and the reaction was continued for 8 h. (3) The mixed solution after the above reaction was naturally cooled to room temperature and transferred to a 100 mL beaker. The Fe3O4 nanoparticles were separated under the action of an external magnetic field, washed several times with anhydrous ethanol, and finally freeze-dried in vacuum for 6 h.

[0020] (3) Shell preparation (1) Activation of Fe3O4 nanoparticles: The ferrite nanoparticles were stirred and activated in a 1.0 M 3-chloropropionic acid solution overnight, and the pH was adjusted to 4 with a 5% NaOH solution. After activation, the Fe3O4 nanoparticles were recovered using a magnet and rinsed with deionized water several times to remove excess 3-chloropropionic acid solution. The activated Fe3O4 nanoparticles were then freeze-dried in a vacuum; (2) Preparation of isotope styrene monomer: 13 C / 14 C-labeled styrene and commercial styrene were mixed evenly under nitrogen protection, with the usage ratio of the two being 1:100; (3) Weigh the activated Fe3O4 nanoparticles in (1) and dissolve them in isotope styrene monomer. Dissolve cuprous chloride and 4,4'-dinonyl-2,2'-bipyridine in xylene, and then add the Fe3O4 nanoparticle / isotope styrene monomer mixture. The amount of Fe3O4 nanoparticles, isotope styrene monomer, cuprous chloride, 4,4'-dinonyl-2,2'-bipyridine, and xylene is 0.3 g: 10 mL: 0.04 g: 0.7 g: 6 mL. (4) Preparation of isotope-labeled shell: Under nitrogen protection, the reaction system in (3) was stirred at 130 °C for 24 h. After the reaction was stopped and naturally cooled to room temperature, the nanoparticles were recovered using a magnet, washed several times with toluene, and air-dried in a fume hood at room temperature.

[0021] Example 2 A method for preparing polystyrene nanoparticles comprises the following steps: (I) Preparation of core (1) Weigh 1.35 g (5 mmol) of ferric chloride hexahydrate into a 100 mL beaker, add 40 mL of ethylene glycol, and stir at room temperature until the ferric chloride hexahydrate is completely dissolved. Keep stirring. (2) 3.6 g of sodium acetate and 1.0 g of polyethylene glycol were added to the mixture. The solution was stirred vigorously for 30 min and then sealed in a stainless steel autoclave (50 mL) lined with polytetrafluoroethylene. The reaction was carried out at 100 °C for 1 h, then the temperature was raised to 200 °C and the reaction was continued for 8 h. (3) The mixed solution after the reaction was naturally cooled to room temperature and transferred to a 100 mL beaker. The Fe3O4 nanoparticles were separated under the action of an external magnetic field, washed several times with anhydrous ethanol, and vacuum freeze-dried for 6 h.

[0022] (2) Shell preparation (1) Activation of Fe3O4 nanoparticles: The ferrite nanoparticles were stirred and activated in a 1.0 M 3-chloropropionic acid solution overnight, and the pH of the solution was adjusted to 4.0 using 5% NaOH. After completion, the Fe3O4 nanoparticles were recovered using a magnet and rinsed with deionized water several times to remove excess 3-chloropropionic acid solution. The activated Fe3O4 nanoparticles were then freeze-dried in a vacuum. (2) Preparation of isotope styrene monomer: 13 C / 14 C-labeled styrene and commercial styrene were mixed evenly under nitrogen protection, with the ratio of the two being 1-1.5:100-300; (3) Reaction system: Weigh the activated Fe3O4 nanoparticles in (1) and dissolve them in isotope styrene monomer. Dissolve cuprous chloride and 4,4'-dinonyl-2,2'-bipyridine in xylene. Then add the Fe3O4 nanoparticle / isotope styrene monomer mixture. The amount of Fe3O4 nanoparticles, isotope styrene monomer, cuprous chloride, 4,4'-dinonyl-2,2'-bipyridine, and xylene is 0.2-0.4 g: 8-12 mL: 0.03-0.05 g: 0.45-0.9 g: 4-8 mL.

[0023] (4) Preparation of isotope-labeled shell: Under nitrogen protection, the reaction system in (3) was stirred at 130 °C for 24 h. After the reaction was stopped and naturally cooled to room temperature, the nanoparticles were recovered using a magnet, washed several times with toluene, and air-dried in a fume hood at room temperature.

[0024] The present invention provides polystyrene nanoparticles prepared by the preparation method described in the above technical solution, wherein the particle size of ferrite in the polystyrene nanoparticles is reduced to below 5 nm.

[0025] ① The polystyrene shell cannot be formed on the outside of the ferrite particles that are not activated by initiator; ② If conventional potassium persulfate is used for polymerization, nanoparticles without ferrite cores are obtained; ③The agglomeration phenomenon may originate from the entanglement of polymer chains during the solvent evaporation process.

[0026] The present invention provides a method for quantitatively detecting the concentration of nanoplastics in fish, comprising the following steps: using a 13 Feeding fish with C-labeled polystyrene nanoplastic feed to obtain poisoned fish; the polystyrene nanoplastic is the polystyrene nanoplastic described in the above technical solution; Prepare samples of fish tissues infected with poison; A control experiment was set up, where fish were fed with feed that did not contain nanoplastics. Using the controlled variable method, only the fish feed was kept different, and tissue samples were also prepared from the fish in the control group. Stable isotope mass spectrometry was used to determine the concentrations of the infected fish, control fish, and 13 C-labeled polystyrene nanoplastics 13 The mass content of C.

[0027] Before the experiment began, 40 13-week-old adult zebrafish (weighing 0.35 ± 0.5 g and measuring 3.5 ± 0.3 cm in length) were randomly selected and transferred to the experimental tank. Following a two-week acclimation period, the 40 zebrafish were randomly divided into two groups: a control group and an experimental group. During the acclimation period, both groups were fed chow twice daily. After the acclimation period, the experimental group was fed twice daily with chow containing the prepared polystyrene nanoparticles, while the control group received a normal diet. After two weeks of feeding, the distribution of the ferrite in the zebrafish was observed using MRI.

[0028] This invention utilizes magnetic resonance imaging (MR) technology to image polystyrene-coated ferrite particles. MRI utilizes static and radiofrequency magnetic fields to detect electromagnetic waves emitted by the decay of energy released by hydronium ions in various tissues and environments within the human body. Clinically, a variety of MRI contrast agents are already used for high-intensity MR scanning. These agents are generally classified into two categories: signal-enhancing contrast agents (T1 contrast agents), which are generally highly biotoxic; and negative contrast agents (T2 contrast agents), which have limited application due to the resulting micro-imaging. The ferrite prepared in this paper is a T2 contrast agent, but research has found that when the ferrite particle size is reduced to below 5 nm, it exhibits a T1-weighted imaging signal. Therefore, ultrasmall ferrites are also widely used as T1 contrast agents in MR imaging.

[0029] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing polystyrene nanoparticles, characterized in that: The following steps are involved: a: Purification of styrene monomer; b: Preparation of Fe3O4 nanoparticles; c: Activated Fe3O4 nanoparticles are weighed and dissolved in an isotope styrene monomer, cuprous chloride and 4,4'-dinonyl-2,2'-bipyridine are dissolved in xylene, and then the Fe3O4 nanoparticle / isotope styrene monomer mixture is added; under a protective gas state, polystyrene nanoparticles are obtained; the particle size of the Fe3O4 nanoparticles is reduced to less than 5 nm.

2. The method for preparing polystyrene nanoparticles according to claim 1, wherein: The purification steps of the styrene monomer are as follows: using a vacuum distillation method to remove the main polymerization inhibitor in styrene, namely hydroquinone; then washing it with NaOH, and then washing it with water until the water is detected to be neutral; drying it with anhydrous magnesium sulfate overnight, and then performing vacuum distillation and continuously extracting it with a water pump.

3. The method for preparing polystyrene nanoparticles according to claim 1, wherein: The steps of preparing Fe3O4 nanoparticles are as follows: weighing ferric chloride hexahydrate into a beaker, weighing a certain amount of ethylene glycol and adding the mixture to the beaker, and stirring at room temperature until the ferric chloride hexahydrate is completely dissolved while maintaining the stirring state; weighing a certain amount of sodium acetate and polyethylene glycol and adding the mixture to the above-mentioned mixture, keeping the solution vigorously stirred for 30 minutes, sealing the mixture in a stainless steel autoclave with a polytetrafluoroethylene liner, reacting at 100°C for 1 hour, then heating the mixture to 200°C and continuing the reaction at this temperature; the solution after the reaction is naturally cooled to room temperature, and transferred to a beaker of appropriate capacity, separating the Fe3O4 nanoparticles therein under the action of an external magnetic field, washing the mixture with anhydrous ethanol several times, and finally freezing the mixture in a vacuum.

4. The method for preparing polystyrene nanoparticles according to claim 1, wherein: The specific steps of step c are as follows: C1: Activation of Fe3O4 nanoparticles: The ferrite nanoparticles were activated by stirring in a 1.0 M 3-chloropropionic acid solution overnight, and the pH was adjusted with a NaOH solution. After activation, the Fe3O4 nanoparticles were recovered using a magnet and washed several times with deionized water to remove excess 3-chloropropionic acid solution. The activated Fe3O4 nanoparticles were freeze-dried. C2: Preparation of isotope styrene monomer: 13 C / 14 C-labeled styrene and commercial styrene were mixed evenly under the protection of nitrogen; C3: Reaction system: Weigh the Fe3O4 nanoparticles activated in step C1 into the isotope styrene monomer, dissolve cuprous chloride and 4,4'-dinonyl-2,2'-bipyridine in xylene, and then add the Fe3O4 nanoparticles / isotope styrene monomer mixture; C4: Preparation of isotope-labeled shell: Under nitrogen, the reaction system in step C3 was stirred at 130°C. After the reaction was stopped, it was naturally cooled at room temperature. The nanoparticles were recovered using a magnet, washed several times with toluene, and finally air-dried in a fume hood.

5. The polystyrene nanoparticles prepared by the preparation method according to any one of claims 1 to 4, characterized in that: The particle size of the ferrite in the polystyrene nanoparticles is reduced to below 5 nm.

6. A method for quantitatively detecting the concentration of nanoplastics in fish, characterized in that: The following steps are involved: Use containing 13 Feeding fish with C-labeled polystyrene nanoplastic feed to obtain poisoned fish; the polystyrene nanoplastic is the polystyrene nanoplastic according to claim 5; Prepare samples of fish tissues infected with poison; A control experiment was set up, where fish were fed with feed that did not contain nanoplastics. Using the controlled variable method, only the fish feed was kept different, and tissue samples were also prepared from the fish in the control group. Stable isotope mass spectrometry was used to determine the concentrations of the infected fish, control fish, and 13 C-labeled polystyrene nanoplastics 13 The mass content of C.