CN108865124B - N, P-doped carbon quantum dot, and preparation method and application thereof - Google Patents
N, P-doped carbon quantum dot, and preparation method and application thereof Download PDFInfo
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- G01N21/6428—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes"
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- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
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- G01N21/64—Fluorescence; Phosphorescence
- G01N21/6428—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes"
- G01N2021/6432—Quenching
Abstract
The invention provides an N, P doped carbon quantum dot, a preparation method and application thereof. The preparation method of the N, P doped carbon quantum dot is simple, and the obtained N, P doped carbon quantum dot can be sensitively used for cobalt ion detection. The preparation method comprises the steps of carrying out hydrothermal reaction on citicoline serving as a carbon source and ethylenediamine, and purifying to obtain the N and P doped carbon quantum dots, wherein the N and P doped carbon quantum dots comprise 47-49% of carbon, 27-29% of oxygen, 17-19% of nitrogen and 3-5% of phosphorus. Preferably, the average particle size of the N, P doped carbon quantum dots is 2.1-3.4 nm, the interlayer spacing is 0.25-0.35 nm, and the average fluorescence lifetime is 3.4-4.0 ns. According to the invention, citicoline is used as a carbon source, the N and P co-doped carbon quantum dots are prepared in one step, and the preparation method is simple; the N and P co-doped carbon quantum dot can be used for detecting cobalt ions in a solution, and the detection limit can reach 53.0 nM.
Description
Technical Field
The invention relates to the technical field of fluorescent carbon nano materials, in particular to an N, P doped carbon quantum dot, and a preparation method and application thereof.
Background
The carbon dots are a new member of a family of carbon nanomaterials, and have many excellent fluorescence properties, such as adjustable fluorescence emission by changing the size and the excitation wavelength, photobleaching resistance and no photoflicker. Carbon element is one of important elements required by organisms, and carbon dots formed by the carbon element have low biological toxicity, and good environmental friendliness and biocompatibility. In addition, the reaction conditions for preparing the carbon dots are mild, the steps are simple, and the raw materials are rich and cheap. The surface of the carbon dot is rich in hydrophilic groups such as carboxyl, hydroxyl and the like, and has good water solubility. Compared with metal quantum dots, the carbon quantum dots are non-toxic, have little harm to the environment and are cheaper in manufacturing cost. The sensor made of it can be used to detect explosive and anthrax. Has good biocompatibility and low toxicity, and is suitable for life science research.
Salinas-Castillo and the like take citric acid as a carbon source, and prepare a carbon quantum dot by microwave pyrolysis in the presence of Polyimide (PEI), wherein the carbon quantum dot has strong fluorescence emission in a range of 450-650 nm, also has good up-conversion luminescence, and can perform Cu up-conversion luminescence2+Has specific detection, therefore, the carbon quantum dots are successfully applied to Cu in cells2+Sensing (ChemCommun, 2013, 49, 1, 13-1105). Qin et al synthesized carbon quantum dots, optionally coated with Hg, using flour as a carbon source2+Quenching for detection of Hg2+The detection limit was 0.5nM (Sensor activators B-ch, 2013, 184, 156-162). Yazid et al use sago starch as carbon source, prepare carbon quantum dots by carbonization and surface oxidation, and the carbon quantum dots can be used as optical probes in aqueous solution to be coated by Sn2+Fast quenching, no influence of other metal ions, and no influence on Sn2+The detection limit was 0.36. mu.M (Anal Chem, 2012, 725, 90-95). Wang et al used boron-doped carbon quantum dots as optical probes for Fe3+Specific detection was carried out with a detection limit of 0.3. mu.M (Microchim acta 2016, 183, 273-279).
Cobalt is one of essential elements of human body and is an important component of vitamin B12. Vitamin B12 can promote hematopoiesis, promote protein metabolism, promote partial enzyme synthesis, and enhance activity. However, some water containing heavy metal cobalt ions at an excessive concentration may cause serious health problems, such as hypotension, paralysis, diarrhea, and bone defects, and may also cause gene mutation of living cells. Radioactive cobalt (e.g., cobalt-60) is also an important nuclear contaminant. Therefore, it is becoming more and more urgent to find a method for effectively detecting cobalt ions.
Recently, Chen's group reported carbon quantum dots as Co2+The detection probe of (1) has a detection limit of 5 μ M, and the preparation of raw materials is troublesome (RSC adv., 2016, 6, 67481-2+Reaction detection of cysteine Quantum dot surface reactive groups to cobaltIons also respond specifically with a detection limit of 2 μ M (RSC adv., 2015, 5, 2285-. The modified cadmium sulfide quantum dot probe is studied by oil h.gore et al to detect cobalt ions, and the inorganic quantum dot is found to have good specificity detection on the cobalt ions (acsappl. mater. interfaces 2012, 4, 5217-. These detection methods can specifically detect cobalt ions, but they have disadvantages of complicated preparation and insufficient sensitivity.
In the process of implementing the invention, the inventor finds that at least the following problems exist in the prior art: the existing carbon quantum dots which can be used for cobalt ion detection not only have complicated preparation method, but also have insufficient sensitivity for cobalt ion detection.
Disclosure of Invention
In view of this, the invention provides an N, P-doped carbon quantum dot, a preparation method and an application thereof, the N, P-doped carbon quantum dot has a simple preparation method, and the obtained N, P-doped carbon quantum dot can be very sensitively used for cobalt ion detection.
Specifically, the method comprises the following technical scheme:
according to the first aspect of the invention, the invention provides a preparation method of N, P doped carbon quantum dots, citicoline is used as a carbon source to carry out hydrothermal reaction with ethylenediamine, the N, P doped carbon quantum dots are obtained by purification,
the N, P doped carbon quantum dot comprises 47-49% of carbon, 27-29% of oxygen, 17-19% of nitrogen and 3-5% of phosphorus by mass percent.
The hydrothermal reaction to obtain the carbon quantum dots is the prior art in the field, and the specific conditions can be determined by the skilled person through experiments.
Preferably, the average particle size of the N, P doped carbon quantum dots is 2.1-3.4 nm, the interlayer spacing is 0.25-0.35 nm, and the average fluorescence lifetime is 3.4-4.0 ns.
Specifically, the raw materials of the hydrothermal reaction comprise citicoline, ethylenediamine and water, and 0.1 +/-0.005 g of ethylenediamine and 10-15 m of L water are added into every 0.3 +/-0.015 g of citicoline.
Preferably, the hydrothermal reaction temperature is 180 to 220 ℃, more preferably 180 to 200 ℃, and most preferably 180 to 190 ℃ (such as 180 ℃, 185 ℃ and the like is most preferred).
Preferably, the hydrothermal reaction time is 4-8 h.
The formation process of the carbon quantum dots by the hydrothermal reaction generally comprises the following steps: first forming various water-soluble polymers; then, the polymer is carbonized at high temperature to form nano dots with disordered structures; and then, as the reaction time increases, the nano-dots of the disordered nano-structure are completely carbonized to form carbon quantum dots with crystal lattices. If the hydrothermal reaction temperature is low or the time is insufficient, carbon quantum dots cannot be formed.
Specifically, the purification method comprises the following steps: and after the hydrothermal reaction product is cooled, centrifuging, filtering, freezing and drying to obtain the N, P doped carbon quantum dot.
Further, in the above-mentioned case,
the cooling is to be carried out to 10-25 ℃;
the centrifugation is carried out for 8-12 min at 11000-13000 rpm;
the temperature of the freeze drying is-50 to-45 ℃, the pressure is 8 to 10Pa, and the processing time is 20 to 28 hours.
Preferably, the hydrothermal reaction comprises the following specific operation steps: adding citicoline and ethylenediamine into water, stirring at the speed of 400-600 r/min at the temperature of 10-25 ℃ to completely dissolve the citicoline and the ethylenediamine (generally, 20-40 min is needed), and then carrying out hydrothermal reaction.
According to a second aspect of the invention, the invention provides the N, P doped carbon quantum dot obtained by the preparation method.
According to a third aspect of the invention, the invention provides application of the N, P-doped carbon quantum dots in detection of cobalt ions.
Taking cobalt ions, preparing cobalt ion solutions with different concentration gradients, adding N and P codoped carbon quantum dots, and detecting the cobalt ion concentration through fluorescence quenching. As the concentration of cobalt ions increases, the fluorescence decreases continuously. The N and P doped carbon quantum dots can be used for detecting cobalt ions in sewage, and the lower detection limit can reach 53.0 nM.
According to the fourth aspect of the invention, the invention provides the application of the N, P-doped carbon quantum dots in detecting vitamin B12 in cells.
A small amount of vitamin B12 is taken to prepare a low-concentration PBS solution, the PBS solution is cultured with cells, and the concentration of fluorescence quenching is observed after the N, P codoped carbon quantum dots are added. The carbon quantum dots have good response to vitamin B12, and fluorescence is continuously weakened along with the increase of the concentration of vitamin B12 in cells. The carbon quantum dot can be used for effectively detecting vitamin B12 in cells, and the detection limit is 81.0 nM.
The N, P-doped carbon quantum dot can also be used for fluorescence imaging of human lung adenocarcinoma cells.
Preparing human lung adenocarcinoma cells into single cell suspension, and placing in CO at 37 deg.C2Inoculating in incubator for 12 hr, discarding original culture solution, adding 0.5mg/m L N, P CO-doped carbon quantum dot water solution prepared with bovine serum albumin (DMEM) culture solution, and adding into CO2And (3) after standing for 4 hours in an incubator, removing the original N and P co-doped carbon quantum dot aqueous solution, washing for 3 times by using a PBS buffer solution, adding a proper amount of 5% paraformaldehyde solution, fixing overnight in a refrigerator at 4 ℃, observing the fluorescence state of the cells under excitation of bright field, ultraviolet light, blue light, green light and red light by using a laser scanning confocal fluorescence microscope, and photographing and recording. The cell morphology is good, and the N, P co-doped carbon quantum dot has no cytotoxicity and can be used for tracking living cells; meanwhile, when the excitation wavelength is 488nm, the cell shows green fluorescence, and when the excitation wavelength is 543nm, the cell shows red fluorescence, which shows that the N and P co-doped carbon quantum dot has multicolor luminescence performance. Specifically, the human lung adenocarcinoma cells are human lung cancer cell A549 cells.
The technical scheme provided by the embodiment of the invention has the beneficial effects that at least:
1. the method uses citicoline as a carbon source to prepare the N and P co-doped carbon quantum dots in one step, and is simple.
2. The N, P codoped carbon quantum dot has small size, has the characteristics of good water solubility, excellent fluorescence property, good biocompatibility and the like, and has high quantum yield.
3. The N and P co-doped carbon quantum dot is most sensitive to cobalt ion detection, and fluorescence is continuously weakened along with the increase of the concentration of cobalt ions. The N, P co-doped carbon quantum dot can be used for detecting cobalt ions in sewage, and has a very low detection limit which can reach 53.0nM (the detection limit of the cobalt ions in the prior art is 210 nM. the detection method comprises the steps of using cadmium sulfide quantum dots, deepening the color of the quantum dots along with the increase of the concentration of the cobalt ions, using a fluorescence spectrophotometer to measure the fluorescence of the quantum dots, and obtaining the concentration of the cobalt ions through calculation).
4. The N, P co-doped carbon quantum dot has good response to vitamin B12, and fluorescence is continuously weakened along with the increase of the concentration of vitamin B12 in cells. The N, P co-doped carbon quantum dot can be used for effectively detecting vitamin B12 in cells, and has a very low detection limit reaching 81.0 nM.
5. The N, P codoped carbon quantum dot realizes the application of cancer cell imaging through cell culture and has the performance of multicolor luminescence.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a transmission electron microscope image of the N, P-codoped carbon quantum dot prepared in example 1 of the present invention, where a is the transmission electron microscope image, and B is a particle size distribution diagram of the N, P-codoped carbon quantum dot.
Fig. 2 is an X-ray diffraction pattern of the N, P co-doped carbon quantum dot prepared in example 1 of the present invention.
Fig. 3 is an emission spectrum of the N, P co-doped carbon quantum dot prepared in example 1 according to the present invention at different excitation wavelengths.
Fig. 4 is an XPS spectrum of the N, P co-doped carbon quantum dot prepared in example 1 of the present invention.
Fig. 5 is a fluorescence spectrum of the N, P co-doped carbon quantum dot prepared in example 1 of the present invention at different pH values.
Fig. 6 is a fluorescence spectrum of the N, P co-doped carbon quantum dot prepared in example 1 of the present invention under different salt concentrations.
FIG. 7 is a graph showing the fluorescence decay curve of N, P-codoped carbon quantum dots prepared in example 1 of the present invention.
Fig. 8 is a combination graph of an ultraviolet absorption spectrum, fluorescence excitation and emission spectrum of the N, P co-doped carbon quantum dot prepared in example 1 of the present invention.
FIG. 9 shows the toxicity test results of the N, P co-doped carbon quantum dots prepared in example 1 and cultured NIH3T3 cells.
Fig. 10 is a graph comparing the relative fluorescence intensities of N, P co-doped carbon quantum dots prepared in example 1 of the present invention under different ions.
Fig. 11 is a fluorescence emission spectrum of the N, P co-doped carbon quantum dot prepared in example 1 of the present invention under different cobalt ion concentrations.
FIG. 12 is a fluorescence emission spectrum of N, P co-doped carbon quantum dots of example 1 of the present invention at different vitamin B12 concentrations.
FIG. 13 is an image of a confocal laser microscope after culturing the N, P-codoped carbon quantum dots and the A549 cells of example 1 of the present invention.
Detailed Description
In order to make the technical solutions and advantages of the present invention clearer, the following will describe embodiments of the present invention in further detail with reference to the accompanying drawings.
According to the first aspect of the invention, the invention provides a preparation method of N, P doped carbon quantum dots, which comprises the steps of taking citicoline as a carbon source, carrying out hydrothermal reaction on citicoline and ethylenediamine, purifying to obtain the N, P doped carbon quantum dots,
the N, P doped carbon quantum dot comprises 47-49% of carbon, 27-29% of oxygen, 17-19% of nitrogen and 3-5% of phosphorus by mass percent.
The hydrothermal reaction to obtain the carbon quantum dots is the prior art in the field, and the specific conditions can be determined by the skilled person through experiments.
Preferably, the average particle size of the N, P doped carbon quantum dots is 2.1-3.4 nm, the interlayer spacing is 0.25-0.35 nm, and the average fluorescence lifetime is 3.4-4.0 ns.
Specifically, the raw materials of the hydrothermal reaction comprise citicoline, ethylenediamine and water, and 0.1 +/-0.005 g of ethylenediamine and 10-15 m of L water are added into every 0.3 +/-0.015 g of citicoline.
Preferably, the hydrothermal reaction temperature is 180 to 220 ℃, preferably 180 to 200 ℃, and more preferably 180 to 190 ℃ (such as 180 ℃, 185 ℃ and the like is the most preferable).
Preferably, the hydrothermal reaction time is 4-8 h.
The formation process of the carbon quantum dots by the hydrothermal reaction generally comprises the following steps: first forming various water-soluble polymers; then, the polymer is carbonized at high temperature to form nano dots with disordered structures; and then, as the reaction time increases, the nano-dots of the disordered nano-structure are completely carbonized to form carbon quantum dots with crystal lattices. If the hydrothermal reaction temperature is low or the time is insufficient, carbon quantum dots cannot be formed.
Specifically, the purification method comprises the following steps: and after the hydrothermal reaction product is cooled, centrifuging, filtering, freezing and drying to obtain the N, P doped carbon quantum dot.
Further, in the above-mentioned case,
the cooling is to be carried out to 10-25 ℃;
the centrifugation is carried out for 8-12 min at 11000-13000 rpm;
the temperature of the freeze drying is-50 to-45 ℃, the pressure is 8 to 10Pa, and the processing time is 20 to 28 hours.
Preferably, the hydrothermal reaction comprises the following specific operation steps: adding citicoline and ethylenediamine into water, stirring at the speed of 400-600 r/min at the temperature of 10-25 ℃ until the citicoline and the ethylenediamine are completely dissolved (generally, 20-40 min is needed), and then carrying out hydrothermal reaction.
According to a second aspect of the invention, the invention provides the N, P doped carbon quantum dot obtained by the preparation method.
According to a third aspect of the invention, the invention provides application of the N, P-doped carbon quantum dots in detection of cobalt ions.
Cobalt ions are taken to prepare cobalt ion solutions with different concentration gradients, the N and P codoped carbon quantum dots are added, and the concentration of the cobalt ions is detected through fluorescence quenching. As the concentration of cobalt ions increases, the fluorescence decreases continuously. The N, P doped carbon quantum dot can be used for detecting cobalt ions in sewage, and the lower detection limit can reach 53.0 nM.
According to the fourth aspect of the invention, the invention provides the application of the N, P-doped carbon quantum dots in detecting vitamin B12 in cells.
A small amount of vitamin B12 is taken to prepare a low-concentration PBS solution, the PBS solution is cultured with cells, and the concentration of fluorescence quenching is observed after the N, P codoped carbon quantum dots are added. The carbon quantum dots have good response to vitamin B12, and fluorescence is continuously weakened along with the increase of the concentration of vitamin B12 in cells. The carbon quantum dot can be used for effectively detecting vitamin B12 in cells, and the detection limit of the carbon quantum dot is 81.0 nM.
The N, P-doped carbon quantum dot can also be used for fluorescence imaging of human lung adenocarcinoma cells.
Preparing human lung adenocarcinoma cells into single cell suspension, and placing in CO at 37 deg.C2After the incubator is inoculated for 12 hours, the original culture solution is discarded, 0.5mg/m L N, P codoped carbon quantum dot aqueous solution prepared by bovine serum albumin DMEM culture solution is added, and CO is added2And (3) after standing for 4 hours in an incubator, removing the original N and P co-doped carbon quantum dot aqueous solution, washing for 3 times by using a PBS buffer solution, adding a proper amount of 5% paraformaldehyde solution, fixing overnight in a refrigerator at 4 ℃, observing the fluorescence state of the cells under excitation of bright field, ultraviolet light, blue light, green light and red light by using a laser scanning confocal fluorescence microscope, and photographing and recording. The cell morphology is found to be good, and the N, P co-doped carbon quantum dot has no cytotoxicity, and can be used for tracking living cells(ii) a Meanwhile, when the excitation wavelength is 488nm, the cell shows green fluorescence, and when the excitation wavelength is 543nm, the cell shows red fluorescence, which shows that the N and P co-doped carbon quantum dot has multicolor luminescence performance. Specifically, the human lung adenocarcinoma cells are human lung cancer cell A549 cells.
The reagents used in the examples of the invention were as follows:
citicoline: the product is produced by Allantin reagent (Shanghai) Limited company, and the purity is 97 percent;
ethylene diamine: the chemical reagent of the national medicine group is produced by chemical reagent company Limited and is analytically pure;
distilled water: self-made, and distilled by deionized water.
Example 1
Preparing N, P codoped carbon quantum dots:
And 2, transferring the colorless solution into a polytetrafluoroethylene hydrothermal reaction kettle, placing the kettle in a vacuum drying oven, and heating the kettle at a constant temperature of 180 ℃ for 8 hours.
And 3, after the reaction is finished, naturally cooling the synthesized product to room temperature to obtain a yellow solution.
And 4, placing the obtained yellow solution in a centrifuge, centrifuging for 10min at the rotating speed of 12000r/min, and filtering by using a 0.22-micron microporous filter head to obtain a clear carbon quantum dot solution.
And 5, carrying out vacuum freeze drying on the obtained clear carbon quantum dot solution, wherein the temperature is-48 ℃, the time is 24h, and the pressure is 8.7Pa, so as to obtain N and P co-doped carbon quantum dot powder.
The following detection is carried out on the obtained N, P co-doped carbon quantum dot powder:
the morphology and dispersion of the sample were observed using an H-7650 transmission electron microscope produced by Hitachi, Japan after air drying at room temperature on a copper mesh coated with 5mg/m L N, P co-doped carbon quantum dot aqueous solution, the results are shown in FIG. 1.
XRD data were collected by an X-ray diffractometer from Bruker, USA under the following test conditions: the copper target, the tube voltage 40KV, the tube current 100mA, the scanning speed 2 °/min, the testing range 10-85 °. The results are shown in FIG. 2. The N, P co-doped carbon quantum dots are shown to have a layer spacing of 0.304nm, similar to the layer spacing in the transmission electron microscope lattice pattern of fig. 1.
The excitation wavelength, emission wavelength and fluorescence intensity of the sample were measured using a Cary Eclipse fluorescence spectrophotometer manufactured by Wailan, USA. Test range: 200-800 nm, excitation slit width: 5nm, emission slit: 5 nm. The results are shown in fig. 3, which shows that the N, P co-doped carbon quantum dots have excitation wavelength dependence.
The sample was characterized by X-ray photoelectron spectroscopy using an Escalab 250 electron spectrometer manufactured by Thermal corporation, USA. The test conditions were: a 500 μm spot, test power 150W, monochromatic Al Ka (hv. 1486.6eV), and an energy analyzer with a fixed transmission energy of 20 eV. The results are shown in FIG. 4. The figure shows that the N-doped carbon quantum dots contain C, N, O and P, wherein the content of C is 58.1%, the content of O is 21.63%, the content of N is 17.2%, and the content of P is 3.07%.
5mM quantum dot solution is respectively prepared in buffer solution under different pH values, and the excitation wavelength, emission wavelength and fluorescence intensity of the sample are tested by adopting a Cary Eclipse fluorescence spectrophotometer produced by Waliana company in America. Test range: 200-800 nm, excitation slit width: 5nm, emission slit: 5 nm. The results are shown in FIG. 5. The fluorescence of the N, P-codoped carbon quantum dots remains stable at pH 1 and 13.
5mM quantum dot solutions are respectively prepared in sodium chloride solutions with different concentrations, and a Cary Eclipse fluorescence spectrophotometer manufactured by Warran, USA is adopted to test the excitation wavelength, the emission wavelength and the fluorescence intensity of a sample, wherein the test range is 200-800 nm, the width of an excitation slit is 5nm, the emission slit is 5nm, the result is shown in figure 6, and when the salt concentration reaches 1 mol/L, the fluorescence of the N and P co-doped carbon quantum dots still keeps stable.
The fluorescence lifetime of the sample was measured by using a FM-4P-TCSPC type steady state/transient state fluorescence spectrometer manufactured by Horiba Jobin Yvon of the United states, and the wavelength range was measured: 200 nm-850 nm, fluorescence life test range: 100ps to 50 mus. The results are shown in FIG. 7. The average fluorescence lifetime of the N, P co-doped carbon quantum dot at an excitation wavelength of 430nm is shown to be 3.59 ns.
The molecular structure of the sample was analyzed using a Cary-50 spectrometer manufactured by Waliana, USA. The test conditions were: the resolution is 0.1nm, the scanning range is 200-800 nm, and the sampling interval of the wave band is 0.5 nm. The results are shown in FIG. 8. The figure shows that the N, P codoped carbon quantum dot has a strong absorption peak at 250nm, which is caused by pi-pi electron transition, the maximum excitation wavelength is 360nm, and the maximum emission wavelength is 440 nm.
Example 2
Preparing N, P codoped carbon quantum dots:
And 2, transferring the colorless solution into a polytetrafluoroethylene hydrothermal reaction kettle, placing the kettle in a vacuum drying oven, and heating for 4 hours at a constant temperature of 180 ℃.
And 3, after the reaction is finished, naturally cooling the synthesized product to room temperature to obtain a yellow solution.
And 4, placing the obtained yellow solution in a centrifuge, centrifuging for 10min at the rotating speed of 12000r/min, and filtering by using a 0.22-micron microporous filter head to obtain a clear carbon quantum dot solution.
And 5, carrying out vacuum freeze drying on the obtained clear carbon quantum dot solution, wherein the temperature is-48 ℃, the time is 24h, and the pressure is 8.7Pa, so as to obtain the N and P co-doped carbon quantum dot powder.
Example 3
Preparing N, P codoped carbon quantum dots:
And 2, transferring the colorless solution into a polytetrafluoroethylene hydrothermal reaction kettle, placing the kettle in a vacuum drying oven, and heating for 6 hours at a constant temperature of 180 ℃.
And 3, after the reaction is finished, naturally cooling the synthesized product to room temperature to obtain a yellow solution.
And 4, placing the obtained yellow solution in a centrifuge, centrifuging for 10min at the rotating speed of 12000r/min, and filtering by using a 0.22-micron microporous filter head to obtain a clear carbon quantum dot solution.
And 5, carrying out vacuum freeze drying on the obtained clear carbon quantum dot solution, wherein the temperature is-48 ℃, the time is 24h, and the pressure is 8.7Pa, so as to obtain the N and P co-doped carbon quantum dot powder.
Example 4
Preparing N, P codoped carbon quantum dots:
And 2, transferring the colorless solution into a polytetrafluoroethylene hydrothermal reaction kettle, placing the kettle in a vacuum drying oven, and heating the kettle at a constant temperature of 180 ℃ for 24 hours.
And 3, after the reaction is finished, naturally cooling the synthesized product to room temperature to obtain a yellow solution.
And 4, placing the obtained yellow solution in a centrifuge, centrifuging for 10min at the rotating speed of 12000r/min, and filtering by using a 0.22-micron microporous filter head to obtain a clear carbon quantum dot solution.
And 5, carrying out vacuum freeze drying on the obtained clear carbon quantum dot solution, wherein the temperature is-48 ℃, the time is 24h, and the pressure is 8.7Pa, so as to obtain the N and P co-doped carbon quantum dot powder.
Example 5
The fluorescence intensity of the N, P co-doped carbon quantum dot powder prepared in examples 1, 2, 3 and 4 was measured using a fluorescence spectrophotometer, and the results are shown in table 1.
TABLE 1 influence of hydrothermal reaction time at 180 ℃ on the fluorescence intensity of quantum dots
| Reaction time/h | 4 | 6 | 8 | 24 |
| Intensity of fluorescence | 520 | 610 | 650 | 550 |
From table 1, the optimal reaction time for synthesizing the N, P-codoped carbon quantum dots by the hydrothermal method at 180 ℃ is 8 h. The influence of the hydrothermal reaction time on the fluorescence intensity is mainly due to the completeness of the final carbonization and the mobility change of the surface groups.
Example 6
Quinine sulfate was used as a reference material with a fluorescence quantum yield of 54%. Firstly, weighing a proper amount of quinine sulfate powder, dissolving the quinine sulfate powder in a 0.1M sulfuric acid solution, and dissolving a proper amount of N, P co-doped carbon quantum dot powder obtained in example 1 in distilled water; then, simultaneously measuring the absorbance values of the N, P co-doped carbon quantum dots and quinine sulfate under the excitation wavelength of 360nm, so that the absorbance values of the N, P co-doped carbon quantum dots and the quinine sulfate are less than or equal to 0.05; and simultaneously, measuring fluorescence emission spectrums of the N and P co-doped carbon quantum dots and the quinine sulfate under the excitation wavelength of 360nm, and calculating the integral fluorescence intensity of the N and P co-doped carbon quantum dots and the quinine sulfate. Finally, the relative fluorescence intensity of the N, P co-doped carbon quantum dots is calculated by the following formula:
in the formula, S and phi R respectively represent the fluorescence quantum yield of a sample and the fluorescence quantum yield of quinine sulfate, FS and FR respectively represent the integrated fluorescence intensity of the sample and the integrated fluorescence intensity of quinine sulfate, AS and AR respectively represent the absorbance value of the sample and the absorbance value of quinine sulfate, η of both is 1.33, the result is shown in table 2, wherein A is absorbance, the quantum yield is 27.03% AS can be seen from the average value of the quantum yield of the quantum dots, and compared with other carbon quantum dots, the quantum yield of the N and P co-doped carbon quantum dots is generally lower than 20%.
TABLE 2 fluorescence quantum yield of N, P codoped carbon quantum dots under different absorbances
Example 7
Thiazolidine (MTT) colorimetric assay is a method of detecting cells and growth. The detection principle is that succinate dehydrogenase in mitochondria of living cells can be reduced into water-insoluble blue-purple Formazan (Formazan) crystals by MTT, and simultaneously the crystals are deposited in the living cells, but dead cells do not have the function. Then, the formazan in the cells is dissolved by dimethyl sulfoxide (DMSO), an enzyme labeling instrument is adopted to detect the absorbance value of a specific absorption wavelength, and the comparison of the absorbance values before and after the addition of the carbon quantum dots is carried out, so that the number of the living cells in the sample can be indirectly reflected. The results are shown in fig. 9 (in fig. 9, the ordinate is cell viability, and the abscissa is different concentrations of carbon quantum dots). The figure shows the cytotoxicity statistics of the N, P codoped carbon quantum dots obtained in example 1. By comparing the cell survival rates of 24h, the cell survival rates are all above 85%, and the cytotoxicity is distributed in 0 grade or 1 grade. The result shows that the N and P co-doped carbon quantum dot has no obvious cytotoxicity and good cell compatibility, and can be applied to the field of biological materials such as cell fluorescence or cell detection.
Example 8
Dissolving various metal ions in distilled water to prepare a 0.5 mu M solution, adding the solution into an equal volume of the N, P co-doped carbon quantum dot aqueous solution prepared in example 1 (10mg/M L), observing the fluorescence under the irradiation of an ultraviolet lamp, and testing the fluorescence emission spectra of the N, P co-doped carbon quantum dot aqueous solutions containing the metal ions, wherein the carbon quantum dots are respectively 0.5mM Na in the figure 10+， K+，Ba2+，Mg2+，Zn2+，Cd2+，Mn2+，Ni2+，Ca2+，Co2+，Ag+，Hg2+，Pb2+，Cu2+，Fe3+And Fe2+Fluorescence response plot in solution, where the ordinate F/F0The ratio of the fluorescence intensity of the metal ions after the carbon quantum dots are added to the fluorescence intensity of the metal ions before the carbon quantum dots are not added is shown. As can be seen from the graph, the ion in which the fluorescence intensity is significantly reduced is Co2+Approximately 80% of the fluorescence is quenched.
Example 9
Cobalt ions are prepared into aqueous solutions with different concentrations, then the aqueous solutions with the same volume of the N and P co-doped carbon quantum dots prepared in example 1 are respectively added, and finally the fluorescence emission spectra of various aqueous solutions of the N and P co-doped carbon quantum dots containing the cobalt ions are tested. With the increase of the concentration of cobalt ions, the fluorescence intensity of the N and P co-doped carbon quantum dots is reduced, when the concentration of cobalt ions is 5.0mM, the fluorescence of the N and P co-doped carbon quantum dots is basically quenched, and the detection limit reaches 53.0nM (the formula detection lower limit Stern-Volmer equation delta F/F is obtained according to FIG. 11)00.00867C +0.00702, inferred at low concentrations), as shown in fig. 11, where the ordinate Δ F/F0The reduction value of the fluorescence intensity of the carbon quantum dots after the metal ions are added and the carbon quantum dots before the metal ions are not addedThe ratio of the fluorescence intensity of the spots, and the abscissa C represents the concentration of cobalt ions.
Example 10
A small amount of vitamin B12 is taken to prepare a low-concentration PBS solution, the concentration of fluorescence quenching is observed after the N and P codoped carbon quantum dots prepared in the embodiment 1 are added (the concentration of the N and P codoped carbon quantum dots is 0.5mg/m L), the fluorescence intensity of the N and P codoped carbon quantum dots is reduced along with the increase of the concentration of the vitamin B12, the fluorescence of the N and P codoped carbon quantum dots is basically quenched when the concentration of the vitamin B12 is 8.0mM, the fluorescence intensity of the N and P codoped carbon quantum dots is reduced along with the increase of the concentration of the vitamin B12, the detection limit reaches 81.0nM, as shown in FIG. 12 (the ordinate is the fluorescence intensity of the carbon quantum dots after the vitamin B12 is added), and a formula shown in FIG. 12 is used to obtain a lower detection limit Stem-Volmer equation, and a/F equation0The detection limit was presumed to be 0.0267C +0.00427, where Δ F/F0The ratio of the decrease in the fluorescence intensity of the carbon quantum dot after the addition of vitamin B12 to the fluorescence intensity of the carbon quantum dot before the addition of vitamin B12 under the excitation of the maximum excitation wavelength of 355nm, wherein C is the concentration of vitamin B12) wherein the concentrations of Top to Bottom are 8.0mM, 7.0mM, 6.0mM, 5.0mM, 4.0mM, 3.0mM, 2.5mM, 2.0mM, 1.5mM, 1.0mM, 0.75mM, 0.5mM, 0.25mM, 125. mu.M, 25. mu.M, 5.0. mu.M, 1.0. mu.M and 0.2. mu.M, respectively.
Example 11
Taking out human lung cancer cell A549 cell with good growth condition, opening the culture bottle under alcohol lamp, discarding the original culture solution, adding 2ml PBS buffer solution to clean the surface of the cell for 2 times, discarding PBS, adding 1ml trypsin digestive juice to fully digest, absorbing appropriate 10% fetal bovine serum DMEM culture solution to stop the digestion, repeatedly blowing gently to blow the cell to make it fall off from the bottle wall to form uniform single cell suspension, absorbing 1m L cell suspension in Petri dish, placing in CO at 37 deg.C2After the incubator is inoculated for 12 hours, the original culture solution is discarded, and N and P codoped carbon quantum dot aqueous solution of 0.5mg/m L prepared by DMEM culture solution is added into the culture solution to perform CO hybridization2Standing in an incubator for 4h, discarding the original N, P codoped carbon quantum dot aqueous solution, washing with PBS buffer solution for 3 times, and addingA proper amount of 5% paraformaldehyde solution is fixed in a refrigerator at 4 ℃ overnight, a laser scanning confocal fluorescence microscope is used for observing the fluorescence state of cells under the excitation of bright field, ultraviolet light (UV), Blue light (Blue), Green light (Green) and Red light (Red), and photographing is carried out for recording, when the excitation wavelength is 488nm, Green fluorescence displayed by the cells is obtained, when the excitation wavelength is 543nm, Red fluorescence displayed by the cells shows that carbon quantum dots have multicolor luminescence performance, the N and P co-doped carbon quantum dot aqueous solution (0.5mg/m L) prepared in example 1 is used for marking A549 cells, as shown in figure 13, the cells are good in shape, and the N and P co-doped carbon quantum dots have no cytotoxicity and can be used for tracking living cells.
Example 12
Preparing N, P codoped carbon quantum dots:
weighing 0.6g of citicoline powder, placing the powder in a clean beaker with the thickness of 50m L, adding 0.2g of ethylenediamine and 30m L of distilled water, completely dissolving to obtain a colorless and transparent aqueous solution, transferring the colorless solution into a polytetrafluoroethylene hydrothermal reaction kettle, placing the kettle in a vacuum drying oven, heating at a constant temperature of 200 ℃ for 8h, after the reaction is finished, naturally cooling a synthesized product to room temperature to obtain a yellow solution, centrifuging and filtering the yellow solution to obtain a N, P-codoped carbon quantum dot solution, and freeze-drying the N, P-codoped carbon quantum dot solution to obtain powder of N, P-codoped carbon quantum dots, wherein the average particle size of the powder is 2.1nm, the composition of the powder has small change compared with the N, P-codoped carbon quantum dots prepared in example 1 (wherein the content of C is 56.2%, the content of O is 24.3%, the content of N is 16.1%, and the content of P is 3.4%), and the fluorescence can be kept stable under different pH values and within salt concentrations.
The above description is only for facilitating the understanding of the technical solutions of the present invention by those skilled in the art, and is not intended to limit the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (5)
1. A preparation method of N, P doped carbon quantum dots is characterized in that,
heating an aqueous solution formed by completely dissolving 0.6g of citicoline, 0.2g of ethylenediamine and 30m of L water at a constant temperature of 180 ℃ for 8 hours to perform hydrothermal reaction;
after the reaction is finished, naturally cooling the synthesized product to room temperature, centrifuging the obtained yellow solution at the rotating speed of 12000r/min for 10min, and filtering by using a 0.22 mu m microporous filter head to obtain a clear carbon quantum dot solution;
carrying out vacuum freeze drying on the clarified carbon quantum dot solution at the temperature of-48 ℃, the time of 24h and the pressure of 8.7Pa to obtain the N, P co-doped carbon quantum dot powder,
the N and P doped carbon quantum dot comprises 58.1% of carbon, 21.63% of oxygen, 17.2% of nitrogen and 3.07% of phosphorus in percentage by mass.
2. A preparation method of N, P doped carbon quantum dots is characterized in that,
heating an aqueous solution formed by completely dissolving 0.6g of citicoline, 0.2g of ethylenediamine and 30m of L water at a constant temperature of 200 ℃ for 8 hours to perform hydrothermal reaction;
after the reaction is finished, naturally cooling a synthesized product to room temperature to obtain a yellow solution, centrifuging and filtering the yellow solution to obtain an N, P co-doped carbon quantum dot solution, and freeze-drying the N, P co-doped carbon quantum dot solution to obtain powder of the N, P co-doped carbon quantum dot;
the N and P doped carbon quantum dot comprises, by mass, 56.2% of carbon, 24.3% of oxygen, 16.1% of nitrogen and 3.4% of phosphorus.
3. The N, P-doped carbon quantum dot obtained by the preparation method of claim 1 or 2.
4. The use of the N, P-doped carbon quantum dots according to claim 3 for detecting cobalt ions.
5. The use of the N, P-doped carbon quantum dots according to claim 3 for detecting vitamin B12 in cells.
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| CN103143035A (en) * | 2013-02-19 | 2013-06-12 | 中国科学院理化技术研究所 | Application of heteroatoms doped aqueous carbon quantum dot in preparation of photo-sensitizers for fluorescent imaging marking and photodynamic therapy (PDT) |
| CN106629660A (en) * | 2016-12-22 | 2017-05-10 | 南京师范大学 | Preparation method of N, P co-doping carbon quantum dots, and product and application thereof |
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