Ratio fluorescence sensor based on fluorescein isothiocyanate labeled metal organic framework and application of ratio fluorescence sensor in escherichia coli detection

Abstract

The invention discloses application of a ratiometric fluorescence sensor based on a fluorescein isothiocyanate labeled metal organic framework in escherichia coli detection. The method comprises the following steps: synthesizing ZTMs by taking TPPS as a ligand, and then fully incubating with FITC to prepare ZTMs (at) FITC; according to the present invention, Escherichia coli is used to reduce Cu < 2 + > to Cu < + >, such that the fluorescence intensity of ZTMs (at) FITC is changed, the fluorescence intensity of the emission peak at the 515 nm position is reduced, the fluorescence intensity of the emission peak at the 683 nm position is increased, and the color of the solution is observed to gradually change from yellow to orange and finally to red under the 365 nm ultraviolet light; and rapid and sensitive detection of the escherichia coli is realized through the ratio of the fluorescence intensities of the two emission peaks. According to the detection method, the accuracy of a detection result is improved, errors caused by environment, instruments and manual operation can be avoided, professional operators are not needed, the method has the advantages of being rapid, simple and independent of expensive instruments and equipment, and the detection cost is reduced.

Description

Technical Field

[0001] The invention belongs to the field of biotechnology, and in particular relates to a ratio fluorescence sensor based on a metal organic framework labeled with fluorescein isothiocyanate and an application thereof in Escherichia coli detection. Background Art

[0002] E. coli is a bacteria found in the intestines of animals. They are also found in the environment and in food. While most E. coli are harmless, some strains can cause illnesses such as food poisoning, pneumonia, urinary tract infections, and acute renal failure, in addition to the well-known and deadly sepsis. As one of the top five pathogens causing foodborne illness in the United States, E. coli is estimated to cause 2,138 hospitalizations each year. Therefore, real-time, in situ measurement and analysis of microorganisms such as E. coli is important to detect these pathogens in food and water early to avoid unnecessary illness, thereby reducing animal and human deaths from consuming contaminated food and water.

[0003] Traditional bacterial culture is still the most commonly used method for bacterial detection and counting. For a long time, the culture method has been considered the standard method for detecting live bacteria. It uses culture media to screen and isolate E. coli based on the growth and reproduction characteristics of E. coli, and then identifies them based on morphological characteristics, physiological and biochemical characteristics, etc. However, culturing and isolating bacteria is time-consuming and labor-intensive, and the process is cumbersome. In addition, positive culture confirms bacterial vitality, but negative results do not necessarily indicate bacterial death, and there is a certain false negative rate. Other methods for detecting E. coli, such as polymerase chain reaction (PCR), can shorten the detection time to several hours, but require cumbersome sample preparation, including nucleic acid extraction and purification, as well as specialized instruments and laboratory staff. Diagnostic techniques such as enzyme-linked immunosorbent assay (ELISA) also have a high probability of false positive or false negative results. In addition, the process is very time-consuming and requires skilled personnel to perform the test and cannot be tested on site to assess the quality of the sample. Other complex techniques, such as matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF) and pulsed field gel electrophoresis (PFGE), require huge initial funding, trained personnel, and lack point-of-care testing capabilities.

[0004] Based on the problems existing in the prior art, it is very necessary to provide a new detection method. Summary of the invention

[0005] The present invention discloses an application of a ratiometric fluorescence sensor based on a metal organic framework labeled with fluorescein isothiocyanate in the detection of Escherichia coli. The fluorescence-based biosensor has the advantages of high sensitivity, rapid response, simple operation and good selectivity, does not require complicated operation and labeling processes, and does not require specialized operators, greatly reducing the detection cost and labor cost.

[0006] The specific technical solutions are as follows:

[0007] The invention provides a ratio fluorescence sensor based on a metal organic framework labeled with fluorescein isothiocyanate and application thereof in Escherichia coli detection.

[0008] Furthermore, the application method includes the following steps: 1) preparing a ratiometric fluorescence sensor based on a metal organic framework labeled with fluorescein isothiocyanate; wherein the ratiometric fluorescence sensor based on a metal organic framework labeled with fluorescein isothiocyanate is denoted as ZTMs@FITC; 2) 2+ The ZTMs@FITC was added to the mixed solution, and the mixture was reacted in the dark at room temperature for 30 minutes. Then, the fluorescence curve of the mixed solution at 440 nm excitation and 200 nm to 800 nm was collected to obtain a calibration curve of the fluorescence intensity ratio of the emission peaks at 515 nm and 683 nm and the concentration of Escherichia coli; 3) at different concentrations of Escherichia coli and Cu 2+ The ZTMs@FITC was added to the mixed solution respectively, and the mixture was reacted in the dark at room temperature for 30 minutes. Then, the fluorescence curve of the mixed solution at 200nm to 800nm ​​was collected under 440nm excitation to obtain the fluorescence intensity ratio of the emission peaks at 515nm and 683nm. The fluorescence intensity ratio was compared with the calibration curve to determine the concentration of Escherichia coli in the sample to be tested.

[0009] Furthermore, in step 2), the concentration of Escherichia coli is 10 1 ~5×10 5 CFU / mL.

[0010] Furthermore, the Escherichia coli or the sample to be tested is 2+ The reaction steps are as follows: Cu 2+ The solution was mixed with the Escherichia coli or the sample to be tested, and incubated in a 37°C bacterial incubator for 1 hour. 2+ Reduction to Cu + .

[0011] Furthermore, in step 2) and step 3), the ZTMs@FITC and the Cu 2+The dosage ratio is 2mg / mL:5mM.

[0012] Furthermore, the step 1) includes: using zirconium as the metal ion and tetraphenylporphyrin tetrasulfonic acid as the organic ligand, synthesizing zirconium-tetraphenylporphyrin tetrasulfonic acid metal organic framework (ZTMs) by a one-pot hydrothermal method; and fully incubating the ZTMs with fluorescein isothiocyanate to obtain the ZTMs@FITC.

[0013] Furthermore, the step 1) specifically includes: dissolving ZrOCl2·8H2O, TPPS and benzoic acid in DMAC, ultrasonically treating and then heating, ultrasonicating and centrifuging in an ice water bath after the reaction is completed, washing the precipitate with DMAC, and vacuum drying to obtain ZTMs; mixing and incubating the ZTMs aqueous solution and the FITC aqueous solution to obtain the ZTMs@FITC.

[0014] Furthermore, the mass ratio of ZrOCl2·8H2O, TPPS, benzoic acid and FITC is (30-60): (10-20): (220-440): (1.5-3.0).

[0015] Furthermore, the heating temperature is 120° C., the heating time is 5 h, and the incubation time is 1 h.

[0016] Furthermore, the ultrasonic power is 450W.

[0017] In summary, the present invention has the following beneficial effects:

[0018] 1. The present invention provides a ratiometric fluorescence sensor based on a metal organic framework labeled with fluorescein isothiocyanate for detecting Escherichia coli. 2+ It will coordinate with ZTMs@FITC to form Cu 2+ -TPPS, resulting in a decrease in the fluorescence intensity of ZTMs@FITC at 683 nm and an increase in the fluorescence intensity at 515 nm. 2+ Reduced to Cu + , Cu 2+ The concentration decreased, specifically F 683 Increase, F 515 Decreased, and observed under 365nm ultraviolet light, it can be seen that with the increase of E. coli concentration, the color of the sample solution gradually changes from yellow to orange and finally to red.

[0019] 2. The present invention is based on the fluorescence intensity ratio (F 683 / F 515) can realize the quantitative detection of Escherichia coli, the detection process is fast, highly sensitive, and has good selectivity. Moreover, the detection of Escherichia coli is carried out according to the change in the ratio of the two signals, which can reduce the interference of external factors and avoid the large changes of a single signal caused by background factors, thereby improving the accuracy and reliability of the detection;

[0020] 3. The present invention does not require a labeling process, is simple and fast to operate, uses low-cost raw materials, does not require professional operators, simplifies the detection method, greatly reduces the cost of pathogenic bacteria detection, and has the advantages of low operating cost, fast and easy detection, high sensitivity, and good selectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present invention and, together with the description, serve to explain the principles of the present invention, in which:

[0022] Figure 1 A flow chart of a method for detecting Escherichia coli using a ratiometric fluorescence sensor based on a metal organic framework labeled with fluorescein isothiocyanate provided in an embodiment of the present invention;

[0023] Figure 2 Characterization of ZTMs provided by embodiments of the present invention;

[0024] Figure 3 The excitation optimization and Cu of ZTMs provided in the embodiment of the present invention 2+ Optimization graph of

[0025] Figure 4 A schematic diagram of a method for detecting Escherichia coli using a ratiometric fluorescence sensor based on a metal organic framework labeled with fluorescein isothiocyanate provided in an embodiment of the present invention;

[0026] Figure 5 In the embodiment of the present invention, a ratiometric fluorescence sensor based on a metal organic framework labeled with fluorescein isothiocyanate is used to detect Escherichia coli;

[0027] Figure 6 It is shown that ZTMs@FITC in the embodiment of the present invention is selective for detecting Escherichia coli. DETAILED DESCRIPTION

[0028] The inventors have found that the ratiometric fluorescence sensor is simple to operate and can detect E. coli quickly and sensitively. The method can avoid large changes in a single signal caused by background factors, thereby improving the accuracy and reliability of detection. Compared with single signal detection, more information about the detection object can be obtained by detecting changes in fluorescence signals at two different wavelengths. This difference can be used to improve the sensitivity of detection, enhance the selectivity of detection, and reduce interference caused by the environment and instruments.

[0029] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and configurations of specific examples are described below.

[0030] Reagents and instruments used in this experiment:

[0031] LB broth was purchased from Qingdao Haibo Biotechnology Co., Ltd. (Qingdao, China). Agar powder was purchased from Beijing Solaibao Technology Co., Ltd. (Beijing, China). Anhydrous cupric chloride and benzoic acid were purchased from Shanghai McLean Biochemical Technology Co., Ltd. (Shanghai, China). Potassium chloride, sodium chloride, anhydrous disodium hydrogen phosphate, and potassium dihydrogen phosphate were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). Zirconium oxychloride octahydrate was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. (Shanghai, China). Tetraphenylporphyrin tetrasulfonic acid was purchased from TCI (Shanghai) Chemical Industry Development Co., Ltd. (Shanghai, China). N,N-dimethylacetamide was purchased from Shanghai Lingfeng Chemical Reagent Co., Ltd. (Shanghai, China).

[0032] The culture medium used in the present invention: LB broth (5g / L yeast extract, 10g / L trypsin and 5g / L NaCl, pH7.0); LB plate (5g / L yeast extract, 10g / L trypsin, 20g / L agar and 5g / L NaCl, pH7.0).

[0033] The morphology of ZTMs was obtained by scanning electron microscopy (zeiss gemini 300, Germany). UV-visible spectra were measured on a UV-visible spectrophotometer (Shimadzu UV-1900i, Japan). The particle size analysis of each sample was measured at 25°C by a Zetasizer Nano ZS nanoparticle size analyzer (Malvern, UK) and measured at least three times after dilution with deionized water. The fluorescence spectrum was measured using an Edinburgh Fs5 integrated fluorescence spectrometer in the UK. The Fourier transform infrared (FT-IR) spectrum was measured using a Thermo Scientific Nicolet IS50 spectrometer in the United States. X-ray photoelectron spectroscopy was measured using a PHI-5000 Versaprobe III (Japan). The absorbance values ​​of the bacterial solution at a wavelength of 600 nm were all measured by a Varioskan LUX multifunctional microplate reader (Thermo Fisher Scientific, USA). All samples were centrifuged in a Centrifuge 5418R refrigerated benchtop microcentrifuge (Eppendorf, Germany).

[0034] Example 1

[0035] ① A method for synthesizing a ratiometric fluorescence sensor based on a metal organic framework labeled with fluorescein isothiocyanate, comprising the following steps:

[0036] 30 mg of ZrOCl2·8H2O, 10 mg of tetraphenylporphyrin tetrasulfonic acid (TPPS) and 220 mg of benzoic acid were dissolved in 10 mL of dimethylacetamide (DMAC) and ultrasonically treated for 10 min. The mixture was then heated to 120 °C and reacted for 5 h. The mixture was ultrasonically treated in an ice-water bath for 30 min (ultrasonic power: 450 W), then centrifuged at 11000 rpm for 5 min, the supernatant was removed, and the precipitate was washed once with DMAC. Finally, zirconium-tetraphenylporphyrin tetrasulfonic acid metal organic framework (ZTMs) powder was obtained by vacuum drying, prepared into a ZTMs solution with a concentration of 2 mg / mL, and then fully incubated with 1.5 mg / mL fluorescein isothiocyanate (FITC) solution to prepare a ZTMs@FITC fluorescent sensor.

[0037] Figure 2 The characterization of ZTMs is shown. Figure 2 A is the SEM image of ZTMs, showing that the average particle size of ZTMs is 23 nm; Figure 2 B shows that the zeta potentials of ZTMs and ZTMs@FITC are -0.174 mV and -0.08337 mV, respectively, indicating that there is an electrostatic interaction between ZTMs and FITC, which provides support for the construction of ZTMs@FITC; Figure 2 C is the UV-visible spectrum of ZTMs, which shows that ZTMs have two obvious UV absorption peaks, located at 434nm and 645nm, corresponding to the Soret and Q bands of TPPS; Figure 2 D is measured by FTIR spectrum of ZTMs, and it is known that in the range of 3300-3670 cm -1 The broad absorption peak at 1483 cm -1 The characteristic peak at 1526-1709 cm -1 Several characteristic absorption peaks in the region are related to the stretching vibration of the NH bond in the active site of the porphyrin core, 950-1070 cm -1 The scattering absorption peak at may be attributed to CH stretching vibration; Figure 2 E is the XPS spectrum of ZTMs, which shows that ZTMs contain four elements: C, N, O, and Zr, and their binding energies are 284.7, 400.1, 531.0, and 182.8 eV, respectively; Figure 2F shows that in the C1s spectrum, there are CC / CH, CN / CS, and -COOH groups in ZTMs, corresponding to the peaks at 284.4, 285.5, and 288.9 eV, respectively; Figure 2 G shows that the two peaks of the N1s spectrum are located at 400.1 eV and 401.9 eV, indicating that the ZTMs are related to pyrrolic-N and graphitic-N; Figure 2 H showed that the two peaks of O1 s at 532.1 eV and 531.0 eV represented -OH and -S=O bonds, respectively; Figure 2 I shows that the two peaks of Zr 3d come from Zr 3d 5 / 2 and Zr 3d 3 / 2 , located at 182.8eV and 185.6eV. The above results indicate that ZTMs were successfully synthesized.

[0038] ② Excitation optimization and Cu ionomer ratiometric fluorescence sensor based on fluorescein isothiocyanate labeled metal organic framework 2+ Optimization:

[0039] (1) Weigh 2 mg of ZTMs and dissolve it in 1 mL of pure water to prepare 2 mg / mL ZTMs;

[0040] (2) The excitation wavelength of ZTMs was measured in the range of 390 to 460 nm to obtain the fluorescence spectrum;

[0041] (3) Weigh 2 mg of ZTMs and dissolve it in 1 mL of pure water to make 2 mg / mL ZTMs. Weigh 1.5 mg of FITC and dissolve it in 1 mL of pure water. Then mix the two and incubate them thoroughly.

[0042] (4) Dilute the bacterial solution with PBS solution to prepare a concentration of 10 5 CFU / mL of Escherichia coli;

[0043] (5) Escherichia coli (10 5 CFU / mL, 10μL) were mixed with 5μL 1mM, 2mM, 3mM, 4mM, 5mM, 6mM, 7mM, and 8mM CuCl2, respectively, and then placed in a 37℃ bacterial incubator for incubation for 1h. After the reaction, ZTMs@FITC (2mg / mL, 41μL), PBS (10μL) and pure water (284μL) were added to react for 30min, and then measured using a fluorescence spectrometer.

[0044] exist Figure 4 middle, Figure 4 A shows that the excitation wavelength of ZTMs was optimized in the range of 390-460 nm, and the fluorescence intensity of the characteristic peak of ZTMs increased continuously from 390 nm, reached the maximum value at 440 nm, and then began to decrease gradually; Figure 4 B shows that the concentration difference of copper ions has a significant effect on the fluorescence of ZTMs@FITC probe. With the increase of copper ion concentration, F 683 / F 515 The value of increases first and then decreases. When the copper ion concentration is 5mM, the ratio reaches the maximum value. The above results show that the optimal excitation wavelength is 440nm and the optimal Cu 2+ The concentration is 5mM. That is, the excitation wavelength of ZTMs after optimization is 440nm, and the optimized Cu 2+ The concentration is 5mM.

[0045] ③ Principle verification of a method for detecting Escherichia coli based on a ratiometric fluorescence sensor of a metal organic framework labeled with fluorescein isothiocyanate, comprising the following steps:

[0046] (1) Weigh 2 mg of ZTMs and dissolve it in 1 mL of pure water to make 2 mg / mL ZTMs. Weigh 1.5 mg of FITC and dissolve it in 1 mL of pure water. Then mix the two and incubate them thoroughly.

[0047] (2) Dilute the bacterial solution with PBS solution to prepare a concentration of 10 5 CFU / mL of Escherichia coli;

[0048] (3) Escherichia coli (10 5 CFU / mL, 10μL) were mixed with CuCl2 (5mM, 5μL) and then incubated in a 37℃ bacterial incubator for 1h. After the reaction, ZTMs@FITC (2mg / mL, 41μL), PBS (10μL) and pure water (284μL) were added to react for 30min and then measured by fluorescence spectrometer. In addition, according to the above reaction conditions, a sample containing only ZTMs@FITC (2mg / mL, 41μL) was prepared as a control.

[0049] Figure 4 It can be seen that ZTMs has a characteristic peak at 683nm and FITC has a characteristic peak at 515nm. When ZTMs and FITC are fully incubated, the fluorescence intensity of ZTMs@FITC is low at 515nm and high at 683nm. 2+ After that, the FL intensity of ZTMs@FITC at 515nm increased significantly, and the FL intensity at 683nm decreased significantly. This is due to the Cu 2+ The porphyrin ligand in ZTMs@FITC was coordinated to form a stable metalloporphyrin Cu 2+ -TPPS complex. After adding E. coli suspension, due to Cu 2+ Reduced to Cu +, the above-mentioned complex cannot be formed, so the fluorescence is restored. Therefore, this experimental method can be used to detect Escherichia coli in the sample.

[0050] ④ The relationship between different E. coli concentrations and F 683 / F 515 Establishment of calibration curve: Detection of different concentrations of E. coli, including the following steps:

[0051] First, dilute the E. coli solution to 5×10 5 , 10 5 , 10 4 , 10 3 , 10 2 , 10 CFU / mL, then CuCl2 (5 mM, 5 μL) was mixed with different concentrations of Escherichia coli (10 1 ~5×10 5 CFU / mL, 10 μL) were mixed in a 1.5 mL centrifuge tube and placed in a 37 °C bacterial incubator for 1 h. ZTMs@FITC (2 mg / mL, 41 μL), PBS (10 μL) and pure water (284 μL) were added for 30 min. Finally, the fluorescence spectrum of the reaction solution in the range of 200-800 nm was measured using a fluorescence spectrometer to obtain the fluorescence spectrum of different E. coli concentrations and F 683 / F 515 The PBS buffer solution contained 0.72 g Na2HPO4, 0.12 g KH2PO4, 4 g NaCl and 0.1 g KCl, with a concentration of 10 mM and a pH of 7.4.

[0052] exist Figure 5 middle, Figure 5 A shows that under the optimal experimental conditions, as the concentration of E. coli increases (from a to g), the reduced Cu + The more metalloporphyrin Cu 2+ The less the -TPPS complex is generated, the lower the emission peak fluorescence intensity of ZTMs@FITC at 515nm and the higher the fluorescence intensity at 683nm. When observed under 365nm ultraviolet light, the color of the sample centrifuge tube gradually changes from yellow to orange and finally to red. Figure 5 B shows that F 683 / F 515 and calibration curves of different concentrations of E. coli (Inset: F 683 / F 515 The linear relationship between the logarithmic concentration of E. coli is 10 1 ~5×10 5 CFU / mL, and the detection limit is 6 CFU / mL).

[0053] ⑤ Selective verification of the ratiometric fluorescence sensor based on fluorescein isothiocyanate-labeled metal organic framework for detecting Escherichia coli, including the following steps:

[0054] The bacterial suspensions of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis were diluted to 10 5 CFU / mL, then CuCl2 (5mM, 5μL) and four bacterial solutions (10μL) were mixed in a 1.5mL centrifuge tube and placed in a 37℃ bacterial incubator for 1h, and then ZTMs@FITC (2mg / mL, 41μL), PBS (10μL) and pure water (284μL) were added for 30min. Finally, the fluorescence spectrum of the reaction solution in the range of 200-800nm ​​was measured using a fluorescence spectrometer to obtain F 683 / F 515 .

[0055] Figure 6 It shows that under the optimal conditions, the fluorescence signal response of this method to E. coli is significantly higher than that of the other three bacteria. In addition, the fluorescence signal measured after the four bacteria are mixed is lower than that of E. coli but higher than that of the other three bacteria, indicating that this method has good selectivity for E. coli in complex environments.

[0056] ⑥ Detection of E. coli concentration in the sample to be tested: CuCl2 (5mM, 5μL) and the sample to be tested (the sample concentration was diluted to the linear range with PBS) were mixed in a 1.5mL centrifuge tube, placed in a 37℃ bacterial incubator for reaction for 1h, and then ZTMs@FITC (2mg / mL, 41μL), PBS (10μL) and pure water (284μL) were added for reaction for 30min. Finally, the fluorescence spectrum of the reaction solution in the range of 200-800nm ​​was measured using a fluorescence spectrometer to obtain F 683 / F 515 Substituting the ratio into the linear equation, the concentration of Escherichia coli in the sample to be tested can be obtained.

[0057] The above is only an exemplary embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. Ratiometric fluorescence sensor based on fluorescein isothiocyanate-labeled metal-organic framework and its application in Escherichia coli detection.

2. The use according to claim 1, characterized in that: The application method comprises the following steps: 1) preparing a ratiometric fluorescence sensor based on a metal organic framework labeled with fluorescein isothiocyanate; wherein the ratiometric fluorescence sensor based on a metal organic framework labeled with fluorescein isothiocyanate is denoted as ZTMs@FITC; 2) At different concentrations of E. coli and Cu 2+ The ZTMs@FITC was added to the mixed solution, respectively, and reacted at room temperature in the dark for 30 minutes, and then the fluorescence curve of the mixed solution at 200nm to 800nm ​​was collected under 440nm excitation to obtain a calibration curve of the fluorescence intensity ratio of the emission peaks at 515nm and 683nm and the concentration of Escherichia coli; 3) At different concentrations of E. coli and Cu 2+ The ZTMs@FITC was added to the mixed solution respectively, and the mixture was reacted in the dark at room temperature for 30 minutes. Then, the fluorescence curve of the mixed solution at 200nm to 800nm ​​was collected under 440nm excitation to obtain the fluorescence intensity ratio of the emission peaks at 515nm and 683nm. The fluorescence intensity ratio was compared with the calibration curve to determine the concentration of Escherichia coli in the sample to be tested.

3. The use according to claim 2, characterized in that: In the step 2), the concentration of the Escherichia coli is 10 1 ~5×10 5 CFU / mL.

4. The use according to claim 2, characterized in that: The Escherichia coli or the sample to be tested is 2+ The reaction steps are as follows: Cu 2+ The solution was mixed with the Escherichia coli or the sample to be tested, and incubated in a 37°C bacterial incubator for 1 hour. 2+ Reduction to Cu + .

5. The use according to claim 2, characterized in that: In the step 2) and step 3), the ZTMs@FITC and the Cu 2+ The dosage ratio is 2mg / mL:5mM.

6. The use according to claim 2, characterized in that: The step 1) comprises: using zirconium as a metal ion and tetraphenylporphyrin tetrasulfonic acid as an organic ligand, synthesizing zirconium-tetraphenylporphyrin tetrasulfonic acid metal organic framework (ZTMs) by a one-pot hydrothermal method; The ZTMs are fully incubated with fluorescein isothiocyanate to obtain the ZTMs@FITC.

7. The use according to claim 2, characterized in that: The step 1) specifically includes: ZrOCl2·8H2O, TPPS and benzoic acid are dissolved in DMAC, subjected to ultrasonic treatment and then heated. After the reaction is completed, the mixture is ultrasonicated and centrifuged in an ice water bath. The precipitate is washed with DMAC and vacuum dried to obtain ZTMs. The ZTMs aqueous solution and the FITC aqueous solution are mixed and incubated to obtain the ZTMs@FITC.

8. The use according to claim 7, characterized in that: The mass ratio of the ZrOCl2·8H2O, TPPS, benzoic acid and FITC is (30-60): (10-20): (220-440): (1.5-3.0).

9. The use according to claim 7, characterized in that: The heating temperature is 120° C., the heating time is 5 h, and the incubation time is 1 h.

10. The use according to claim 7, characterized in that: The ultrasonic power is 450W.

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