A fluorescence probe based on upconversion nanomaterials and application thereof

Abstract

The application discloses a fluorescence probe based on up-conversion nanomaterials and application thereof, and relates to the technical field of fluorescence probes. The application uses up-conversion fluorescence as a detection light signal, uses the fluorescence inner filter effect caused by the red shift of ultraviolet absorption spectrum of a complex formed by the combination of an acid dye and an amine compound to cause the quenching of up-conversion fluorescence, so that the detection of the amine compound is realized. Meanwhile, the synergistic effect of the photocatalyst after absorbing the up-conversion fluorescence energy is used to enhance the photocatalytic effect and the adsorption effect to degrade the acid dye and the amine compound, so that the solution is purified.

Description

Technical Field

[0001] This invention relates to the field of fluorescent probe technology, specifically to a fluorescent probe based on upconversion nanomaterials and its application in the detection and degradation of amine compounds. Upconversion nanomaterials can convert low-energy photons (such as near-infrared light) into high-energy photons (such as visible light). This property, when combined with photocatalysts, can improve photocatalytic efficiency, especially under infrared light irradiation. Background Technology

[0002] Amines are an important class of organic compounds that can be used not only as pharmaceutical intermediates in drug synthesis but also directly as drugs. When amines are impurities or contaminants, their residue problems need to be addressed.

[0003] Rare-earth-doped upconversion luminescent nanoparticles are an important class of luminescent materials that can convert low-frequency excitation light into high-frequency emission light through two-photon or multi-photon mechanisms. They possess advantages such as good stability, high luminescence intensity, and large Stokes shift. Furthermore, their excitation light is infrared, which avoids interference from biological autofluorescence and scattered light phenomena, reducing detection background and improving the signal-to-noise ratio. Therefore, the application of rare-earth-doped upconversion luminescent nanoparticles as a novel labeling agent in the field of bioanalysis has attracted considerable attention.

[0004] Fluorescent dyes are substances that absorb a certain wavelength of light and then emit another wavelength of light with a longer wavelength than the absorbed light. They are often used in bioimaging and drug delivery research and can generate specific signals by binding to target molecules.

[0005] The working principle of photocatalysts involves the formation of photo-excited electron-hole pairs, which are then utilized to participate in catalytic reactions. Through photocatalytic processes, photocatalysts can be applied to environmental and energy-related fields such as water splitting and photocatalytic degradation of organic pollutants.

[0006] This invention aims to provide a fluorescent probe that can be used for the simultaneous detection and degradation of amine compounds, based on the characteristics of fluorescent dyes, rare earth-doped upconversion luminescent nanoparticles, and photocatalysts. Summary of the Invention

[0007] The technical problem to be solved by this invention is to provide a fluorescent probe based on upconversion nanomaterials and a fluorescent probe based on upconversion nanomaterials and a photocatalyst. The upconversion fluorescence is used as the detection light signal. The fluorescence internal filtering effect is generated by the red shift of the ultraviolet absorption spectrum caused by the complex formed by the combination of acidic dyes and amine compounds, which leads to the quenching of upconversion fluorescence, thereby realizing the detection of amine compounds. At the same time, the photocatalyst can be used to degrade acidic dyes and amine compounds by the photocatalyst after absorbing the upconversion fluorescence energy and the near-infrared light excitation of the photocatalyst to enhance its adsorption effect, thereby achieving the effect of purifying the solution.

[0008] The technical problem to be solved by this invention is achieved by the following technical solution:

[0009] The first objective of this invention is to provide a fluorescent probe based on upconversion nanomaterials, including rare earth-doped upconversion nanoparticles and acid dyes.

[0010] A second objective of this invention is to provide the application of the fluorescent probe based on upconversion nanomaterials in the detection of amine compounds.

[0011] A third objective of this invention is to provide a fluorescent probe based on upconversion nanomaterials and photocatalysts, including rare earth-doped upconversion nanoparticles, acid dyes, and photocatalysts.

[0012] The fourth objective of this invention is to provide the application of the fluorescent probe based on upconversion nanomaterials and photocatalysts in the detection and degradation of amine compounds.

[0013] The beneficial effects of this invention are:

[0014] 1. The fluorescent probe based on upconversion nanomaterials provided by this invention can be used for the detection of amine compounds. Positively charged amine compounds combine with negatively charged acid dyes to form a complex. This complex can cause a red shift in the ultraviolet absorption spectrum, resulting in the quenching of the green light emission spectrum of the upconversion nanoparticles, thereby achieving the purpose of detecting amine compounds.

[0015] 2. The fluorescent probe based on upconversion nanomaterials and photocatalysts provided in this invention can not only be used for the detection of amine compounds, but also for the degradation of amine compounds and acidic dyes. Upconversion fluorescence enhances the photocatalytic activity of the photocatalyst, improving the degradation efficiency of amine compounds and acidic dyes. Simultaneously, the adsorption of acidic dyes by the photocatalyst restores the quenched upconversion fluorescence, further strengthening the degradation effect of the photocatalyst on amine compounds, thus achieving the effect of purifying the solution. Attached Figure Description

[0016] Figure 1A is a scanning electron microscope image of the rare earth-doped upconversion nanoparticles in Example 1; Figure 1 B is a scanning electron microscope image of the MoS2 nanosheets in Example 2; Figure 1 C is a high-resolution transmission electron microscope image of MoS2 nanosheets in Example 2;

[0017] Figure 2 A is the UV-Vis absorption spectrum of the mixed solution in Example 4 at different pH values; Figure 2 B shows the fluorescence spectra of the mixed solution in Example 4 at different pH values ​​when irradiated with near-infrared light;

[0018] Figure 3 A and Figure 3 B represents the fluorescence intensity of the mixed solution before and after the addition of ciprofloxacin in Example 4 at different eosin concentrations; Figure 3 C is Figure 3 A and Figure 3 The difference in fluorescence intensity of B;

[0019] Figure 4 The sensitivity curve for detecting ciprofloxacin using fluorescent probe A prepared in Example 3;

[0020] Figure 5 The degradation effect of fluorescent probe B prepared in Example 3 on ciprofloxacin;

[0021] Figure 6 The degradation effect of fluorescent probe B prepared in Example 3 on eosin;

[0022] Figure 7 The image shows the UV-Vis absorption spectrum of the MoS2 nanosheets in Example 2. Detailed Implementation

[0023] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific embodiments and illustrations.

[0024] This invention provides a fluorescent probe based on upconversion nanomaterials, comprising rare earth-doped upconversion nanoparticles and acid dyes.

[0025] The present invention also provides a fluorescent probe based on upconversion nanomaterials and photocatalysts, including rare earth-doped upconversion nanoparticles, acid dyes and photocatalysts.

[0026] Furthermore, the rare earth-doped upconversion nanoparticles are NaYF4:Yb,Er@NaYF4 nanoparticles, with NaYF4:Yb,Er as the core and NaYF4 as the shell. Preferably, the NaYF4:Yb,Er@NaYF4 nanoparticles are NaYF4:18%Yb,2%Er@NaYF4 nanoparticles, with NaYF4:20%Yb,2%Er nanoparticles as the core.

[0027] Furthermore, the acidic dye is at least one of eosin, eosin, and acid fuchsin, but is not limited thereto. Acidic dyes can combine with amine compounds via ionic bonds, and the resulting complexes can quench upconversion fluorescence through an internal rate effect.

[0028] Furthermore, the photocatalyst is at least one of semiconductor quantum dots and transition metal photosensitizers, but is not limited thereto. Preferably, the transition metal photosensitizer is molybdenum disulfide (MoS2). The photocatalyst generates highly oxidizing substances such as hydroxyl radicals and oxygen under light irradiation, which can be used to decompose organic compounds.

[0029] Furthermore, the molybdenum disulfide nanosheets are prepared by a hydrothermal reaction of a sulfur source and a molybdenum source. Preferably, the sulfur source is at least one of thiourea, thioacetamide, and ammonium polysulfides, but not limited thereto; the molybdenum source is at least one of ammonium molybdate, sodium molybdate, molybdenum dichlorodioxide, and molybdenum trioxide, but not limited thereto. Selecting suitable sulfur and molybdenum sources is crucial for obtaining molybdenum disulfide with the desired morphology and size. Different sulfur and molybdenum sources may affect the crystal structure, crystallinity, and layered stacking properties of the final product.

[0030] This invention also provides the application of the fluorescent probe based on upconversion nanomaterials in the detection of amine compounds.

[0031] This invention also provides the application of the fluorescent probe based on upconversion nanomaterials and photocatalysts in the detection and degradation of amine compounds.

[0032] Furthermore, the amine compound is at least one of ciprofloxacin, erythromycin, and azithromycin, but is not limited thereto. Any compound containing an amine group in its molecular structure can be detected and degraded using the fluorescent probe described in this invention.

[0033] Example 1

[0034] Preparation of rare earth-doped upconversion nanoparticles:

[0035] (1) 1.56 mmol YCl3·6H2O, 0.4 mmol YbCl3·6H2O, 0.04 mmol ErCl3·6H2O were heated with 20 mL oleic acid and 30 mL 1-octadecene to 150 °C and stirred for 30 min to form a transparent solution. After cooling to room temperature, 20 mL of methanol solution containing 5 mmol NaOH and 8 mmol NH4F was slowly added. The reaction was carried out at 45 °C for 30 min. After removing the methanol, the temperature was raised to 100 °C and vacuum treated for 10 min. Then, the temperature was raised to 300 °C and held for 1 h under argon protection. After cooling to room temperature, the nanocrystals were precipitated with ethanol and washed three times with ethanol / water (v / v = 1:1) solution. The obtained NaYF4:20%Yb,2%Er nanoparticles were dissolved in 4 mL cyclohexane for later use.

[0036] (2) 1 mmol YCl3·6H2O was heated to 150℃ with 6 mL oleic acid and 15 mL 1-octadecene and stirred for 30 min to form a transparent solution. After cooling to room temperature, a cyclohexane solution of the NaYF4:20%Yb,2%Er nanoparticles prepared above was added. After removing the cyclohexane, 10 mL of methanol solution containing 4 mmol NH4F and 2.5 mmol NaOH was added. The reaction was carried out at 50℃ for 30 min, and then heated to 300℃ and kept at 1 h under argon protection. After cooling to room temperature, the nanocrystals were collected, centrifuged, and the obtained NaYF4:18%Yb,2%Er@NaYF4 nanoparticles were dispersed in 6 mL cyclohexane for later use.

[0037] from Figure 1 As can be seen from A, the upconversion nanoparticles prepared in Example 1 are hexagonal, approximately spherical particles.

[0038] Example 2

[0039] Preparation of MoS2 nanosheets:

[0040] 0.798 g thiourea, 0.618 g ammonium molybdate tetrahydrate and 0.618 g oxalic acid were dissolved in 30 mL deionized water and stirred for 30 min. The mixture was then placed in a 50 mL polytetrafluoroethylene-lined reactor and hydrothermally reacted at 200 °C for 24 h. The product was washed three times with anhydrous ethanol and deionized water and dried in a vacuum drying oven at 80 °C for 5 h to obtain MoS2 nanosheets.

[0041] from Figure 1 B and Figure 1 As can be seen from C, the MoS2 nanosheets prepared in Example 1 are stacked layer by layer to form a flower-like spherical structure, and band gap defects and lattice fringes are visible (the band gap defects and lattice fringes of MoS2 are important factors affecting its photoelectric properties).

[0042] Example 3

[0043] Preparation of fluorescent probes:

[0044] The rare earth-doped upconversion nanoparticles prepared in Example 1 were ultrasonically vibrated in a 1 mol / L hydrochloric acid solution for 1 h, and then mixed with eosin to obtain fluorescent probe A.

[0045] The rare earth-doped upconversion nanoparticles prepared in Example 1 were ultrasonically vibrated in a 1 mol / L hydrochloric acid solution for 1 h, and then mixed with the MoS2 nanosheets prepared in Example 2 and eosin to obtain fluorescent probe B.

[0046] Example 4

[0047] Optimization of ciprofloxacin (CIP) detection conditions and sensitivity testing:

[0048] Fluorescent probe A prepared in Example 3 was added to an aqueous solution containing ciprofloxacin and mixed thoroughly to obtain a mixed solution. The concentration of rare earth-doped upconversion nanoparticles was 1 μmol / L, the concentration of eosin was 50 nmol / L, and the concentration of ciprofloxacin was 25 nmol / L.

[0049] The pH of the mixed solutions was adjusted (from 1 to 14), and the absorbance was measured using a UV-Vis spectrophotometer. The mixed solutions at different pH values ​​were then irradiated with 980 nm near-infrared light, and the fluorescence intensity was measured using a fluorescence spectrometer. Figure 2 It can be seen that the absorption spectrum exhibits the most significant red shift under acidic conditions at pH=3, indicating that the eosin-ciprofloxacin complex has the strongest quenching effect on upconversion fluorescence. Therefore, pH=3 is the optimal pH value for the fluorescent probe of this invention to detect ciprofloxacin.

[0050] The eosin content in the mixed solution was adjusted (0–180 μmol / L). Mixed solutions with different eosin contents were irradiated with 980 nm near-infrared light under both conditions (without ciprofloxacin and with ciprofloxacin), and the fluorescence intensity was measured using a fluorescence spectrometer at pH 3. Figure 3 It can be seen that the quenching effect of upconversion fluorescence is most significant when the eosin concentration is 10 μmol / L. Therefore, the optimal eosin concentration for the fluorescent probe of this invention to detect ciprofloxacin is 10 μmol / L.

[0051] The ciprofloxacin content in the mixed solution was adjusted (0–20 μmol / L), and the mixed solutions with different ciprofloxacin contents were irradiated with 980 nm near-infrared light. The fluorescence intensity was measured using a fluorescence spectrometer at pH 3 and an eosin concentration of 10 μmol / L. Figure 4 It can be seen that the concentration of ciprofloxacin is linearly related to the fluorescence intensity in the range of 0 to 10 μmol / L. Therefore, the fluorescent probe of this invention can be used to detect residual ciprofloxacin.

[0052] Example 5

[0053] Degradation of ciprofloxacin and eosin:

[0054] Fluorescent probe B prepared in Example 3 was added to a solution containing ciprofloxacin. The concentration of eosin was 10 μmol / L, the concentration of ciprofloxacin was 25 nmol / L, and the concentration of rare earth-doped upconversion nanoparticles was 1 μmol / L. The solution was continuously irradiated with 980 nm near-infrared light, and the absorbance was measured using a UV-Vis spectrophotometer at 0 min, 30 min, 1 h, and 2 h of continuous near-infrared irradiation. Figure 5 and Figure 6 It can be seen that the degradation rate of ciprofloxacin reaches 80% after 2 hours, and the degradation rate of eosin reaches 99% after 30 minutes. This indicates that the addition of molybdenum disulfide to the fluorescent probe of this invention can produce a good photocatalytic degradation effect on ciprofloxacin and eosin.

[0055] from Figure 7 As can be seen, the main absorption peak of the MoS2 nanosheets prepared in Example 2 is in the visible light region. This invention utilizes rare earth-doped upconversion nanoparticles to convert 980nm near-infrared light into visible light as an excitation source for MoS2, thereby achieving the dual purpose of detecting and degrading ciprofloxacin.

[0056] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A fluorescent probe based on upconversion nanomaterials and a photocatalyst, characterized in that: This includes rare earth-doped upconversion nanoparticles, acid dyes, and photocatalysts; The rare earth-doped upconversion nanoparticles are NaYF4:Yb,Er@NaYF4 nanoparticles. The acid dye is eosin; the photocatalyst is molybdenum disulfide nanosheets prepared by hydrothermal reaction of a sulfur source and a molybdenum source.

2. The fluorescent probe based on upconversion nanomaterials and photocatalyst according to claim 1, characterized in that: The NaYF4:Yb,Er@NaYF4 nanoparticles are NaYF4:18%Yb,2%Er@NaYF4 nanoparticles, with NaYF4:20%Yb,2%Er nanoparticles as the core and NaYF4 as the outer shell.

3. The fluorescent probe based on upconversion nanomaterials and photocatalyst according to claim 1, characterized in that: The sulfur source is at least one of thiourea, thioacetamide, and ammonium polysulfide; the molybdenum source is at least one of ammonium molybdate, sodium molybdate, molybdenum dioxide, and molybdenum trioxide.

4. The application of the fluorescent probe based on upconversion nanomaterials and photocatalyst as described in any one of claims 1-3 in the detection and degradation of ciprofloxacin.

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