A metal-organic framework-based biosensor and its preparation method

Abstract

The present invention provides a metal-organic framework MNP / Cu-BTC MOF and its preparation and application as a tumor-derived exosome capturer. The present invention realizes the capture of exosomes through the interaction between metal ions in the metal-organic framework and the phospholipid structure on tumor-derived exosomes. The tumor-derived exosome capturer based on the metal-organic framework of the present invention can achieve simple, convenient, structure-modification-free detection of tumor exosomes with good active sites and biocompatibility. The tumor-derived exosome capturer based on the metal-organic framework developed by the present invention provides a new platform for ultrasensitive and low-cost biological detection, and provides new tools for cancer detection and continuous monitoring, treatment based on precision medicine, and screening of therapeutic resistance markers.

Description

Technical Field

[0001] The present invention belongs to the technical fields of polymer composites and biosensing detection, and particularly relates to a biosensor based on metal-organic framework and a preparation method thereof, and more particularly to a metal-organic framework MNP / Cu-BTC MOF and its application as a tumor-derived exosome capturer. Background Art

[0002] As an extracellular membrane vesicle with a diameter of 30-150 nm, exosomes are distributed in different biological body fluids, such as blood, cerebrospinal fluid, saliva, and urine. Because they are rich in proteins, mRNAs, and miRNAs, they are considered potential biomarkers for tumors and are widely used clinically. These vesicles (exosomes) all contain a phospholipid structure, which, as an intercellular messenger, actively participates in various pathophysiological processes such as inflammation, tissue regeneration, and cancer metastasis. Recently, researchers have found that the number of exosomes secreted by cancer cells is significantly higher than that of normal cells, and tumor exosomes contain unique nucleic acid or protein markers, making them potential biomarkers for non-invasive cancer diagnosis. However, the low concentration of these species and the cross-reaction between monomers and oligomers have hindered the development of highly sensitive and reliable detection techniques. For this reason, despite many obstacles, different methods have been developed to analyze tumor exosomes. For example, according to the structure of exosomes, the ultracentrifugation technique is often used to purify exosomes from complex biological media, but the detection process is quite complex and time-consuming. In addition, the immunoaffinity capture technique has high specificity, simple operation, and does not affect the integrity of exosomes, but its overall efficiency is still low and expensive antibodies are required. Therefore, developing a capturer that can not only meet the simple and efficient collection of exosomes but also meet the subsequent highly sensitive and selective detection is still a daunting task.

[0003] Metal-organic frameworks (MOFs) are composed of metal ions and organic linkers and show broad application prospects in the fields of gas storage, energy, drug delivery, and biosensing due to their advantages such as easy synthesis, low cost, tunable porosity, and flexible modification. Especially in the field of biosensing, MOFs can be combined with different recognition elements, such as DNA, polypeptides, and proteins, through strong interactions between metal nodes and certain groups (such as phosphates or imidazoles). Therefore, the synthesized nanoconjugates can effectively recognize and capture analytes from complex media. Summary of the Invention

[0004] The object of the present invention is to provide a metal-organic framework MNP / Cu-BTC MOF and its preparation and application as a tumor-derived exosome capturer. The metal ions in the metal-organic framework interact with the phospholipid structure on the tumor-derived exosomes for recognition, and the capture efficiency is determined by fluorescence spectroscopy for biosensing and analytical detection. To achieve the above technical object, the present invention adopts the following technical solutions:

[0005] First of all, the present invention provides a metal-organic framework MNP / Cu-BTC MOF, which is mainly composed of 1,3,5-benzenetricarboxylic acid (BTC), copper chloride dihydrate, and superparamagnetic silica-coated magnetic beads (MNP). It has a rod-like morphology as a whole, with an average diameter of about 5-20 μm and a length range of 80-160 μm. Among them, Cu 2+ forms a rod-like framework structure of MOF with BTC, and the magnetic beads MNP are spherical and attached to the surface of the rod-like structure. The average diameter of the rod-like morphology of the metal-organic framework (MNP / Cu-BTC MOFs) can be 5 μm, 10 μm, 15 μm, 20 μm; the length range can be 80 μm, 100 μm, 120 μm, 140 μm, 160 μm. Among them, the superparamagnetic silica-coated magnetic beads (MNP) are silica magnetic beads, with a particle size of 300-500 nanometers, preferably about 400 nm. They can be commercially available silica hydroxyl magnetic beads, or Fe 3 O 4 / SiO 2 obtained by common one-pot chemical synthesis.

[0006] On the other hand, the present invention also provides a preparation method of the above-mentioned metal-organic framework MNP / Cu-BTC MOF, which is to add BTC to MNP, then add copper chloride dihydrate, and react at room temperature; magnetic separation, washing, and drying. The molar ratio of BTC to copper chloride dihydrate is 1:1-3.

[0007] As an implementation scheme of the above-mentioned preparation method, preferably, 1 mL of 0.1-0.2 M BTC ethanol solution can be added to 10-50 μL of 30-50 μg / mL MNPs ethanol solution, and continuously stirred. Then, 1 mL of 0.1-0.3 M CuCl 2 solution is slowly added to the above solution to prepare a reaction solution with a total volume of 2 mL, and stirred at room temperature for 10-60 min.

[0008] As a specific implementation scheme of the above-mentioned preparation method, 1 mL of 0.125 M BTC ethanol solution can be added to 50 μL of 40 μg / mL MNPs ethanol solution, and continuously stirred. Then, 1 mL of 0.2 M CuCl 2The solution was slowly added to the above solution to prepare a reaction solution with a total volume of 2 mL, and stirred at room temperature for 0.5 h.

[0009] Preferably, the magnetic separation washing and drying can be carried out by magnetically separating the prepared MNP / Cu-BTC MOF solution for 3 - 8 min, separating the supernatant and the precipitate, washing the bottom precipitate with pure water 2 - 5 times to obtain the final product; putting the obtained final product solution into a vacuum drying oven to dry to obtain the finished product.

[0010] Second, the inventors of the present application found through research that the metal-organic framework MNP / Cu-BTC MOF described in the present invention can be used as a tumor-derived exosome catcher.

[0011] In the above application, preferably, first, tumor-derived exosomes need to be obtained through an exosome extraction kit and labeled with a fluorescent dye to prepare fluorescently labeled tumor-derived exosomes. Specifically, the preparation of the fluorescently labeled tumor-derived exosomes can adopt the following method steps:

[0012] The supernatant in the tumor cell culture flask was collected into a test tube, and exosomes from tumor cells were collected according to the extraction kit; the extracted exosomes were incubated with the fluorescent dye to obtain fluorescently labeled exosomes; the fluorescent dye-labeled exosomes were purified by dialysis and stored in a refrigerator at -20 - -40 °C.

[0013] In the above application, as a preferred application scheme, the application can adopt the following step method: using the metal-organic framework MNP / Cu-BTC MOF as a catcher, co-incubating it with the fluorescently labeled tumor-derived exosomes at room temperature, and determining its capture efficiency through fluorescence spectroscopy, so as to be used for biosensing analysis and detection.

[0014] In the above application, preferably, after the room temperature co-incubation, magnetic separation, discarding the supernatant, and resuspending the precipitate are required to obtain a tumor-derived exosome catcher based on the metal-organic framework, and then it is used for fluorescence spectroscopy analysis and detection of clinical samples derived from tumors; a more preferred application method is to incubate 5 μL of fluorescently labeled tumor-derived exosomes with 45 μL of MNP / Cu-BTC MOFs solution (50 μg / mL) in the dark at room temperature for 15 min, magnetically separate for 5 min, and resuspend with HEPES buffer solution to obtain a tumor-derived exosome catcher based on the metal-organic framework, so as to further be used for the analysis and detection of clinical samples derived from tumors.

[0015] In the above-mentioned application, preferably, the tumor-derived exosomes can be exosomes derived from various tumors, including exosomes of breast cancer cell MCF-7, exosomes of breast cancer cell SK-BR-3, exosomes of human malignant melanoma cell A-375, exosomes of pancreatic cancer cell line BxPC-1, etc.; more preferably, they are exosomes of breast cancer cell SK-BR-3, with a particle size range of 30-150 nm and showing red fluorescence.

[0016] In the above-mentioned application, when the tumor-derived exosomes are exosomes of breast cancer cell SK-BR-3, the method for preparing fluorescently labeled tumor-derived exosomes or extracting fluorescently labeled tumor-derived exosomes may include the following steps:

[0017] Step (2.1): Collect the supernatant in the culture flask of breast cancer cells (SK-BR-3) into a test tube, and collect the exosomes secreted by SK-BR-3 breast cancer cells according to the extraction kit.

[0018] Step (2.2): Incubate the extracted exosomes with a fluorescent dye (Dil) to obtain fluorescently labeled exosomes.

[0019] Step (2.3): Purify the Dil-labeled exosomes by dialysis and store them in a -20 °C refrigerator.

[0020] Preferably in the above extraction method, in step (2.1), use a pipette to aspirate 5 mL of the culture supernatant of SK-BR-3 breast cancer cells, and add 1.25 mL of Hieff TM Quick exosome extraction reagent and let it stand at 4 °C for 5 h; then centrifuge the above mixture at 4 °C and 10,000 rpm for 1 h, collect the bottom precipitate, resuspend it in a PBS buffer solution in a 2 mL EP tube; then centrifuge at 4 °C and 14,000 rpm for 1 min, collect the supernatant and store it in a -20 °C refrigerator.

[0021] Preferably in the above extraction method, in step (2.2), take 99 μL of the above-collected exosome solution and incubate it with 1 μL of Dil in the dark at low temperature for 15 min. Then ultra-centrifuge the mixture at 100,000 rpm and 4 °C for 1 h, and pipette the tube wall and the bottom precipitate with a PBS buffer solution to obtain a resuspended solution.

[0022] Preferably in the above extraction method, in step (2.3), place the above fluorescently labeled exosome sample in a dialysis bag, react overnight to remove the free Dil dye, and finally obtain a pure fluorescently labeled exosome solution.

[0023] In the above-mentioned application, preferably, a tumor-derived exosome capturer based on a metal-organic framework prepared from a metal-organic framework (MNP / Cu-BTC MOF) and fluorescently labeled tumor-derived exosomes has a capture efficiency of 80-96%.

[0024] Beneficial effects

[0025] On the one hand, in the present invention, the metal ion Cu in the metal-organic framework 2+ interacts with the phospholipid structure on the tumor-derived exosomes. At the same time, based on the good binding properties of MNP to organisms, ultrasensitive capture and adsorption of exosomes can be achieved. In addition, the MNP magnetism carried by the metal-organic framework itself in the present invention can be used for magnetic sorting of the complex to achieve rapid and simple separation. Furthermore, through the fluorescence spectrum displayed by the fluorescent molecule, intuitive analysis of tumor-derived exosomes can be realized.

[0026] The tumor-derived exosome capturer based on the metal-organic framework of the present invention can simply and conveniently adsorb the metal-organic framework on the surface of exosomes without structural modification, and has good active sites and biocompatibility. Therefore, the developed tumor-derived exosome capturer provides new ideas for an ultrasensitive and low-cost detection platform, opening up new ways for cancer detection and continuous monitoring, treatment based on precision medicine, and screening of therapeutic resistance markers. Description of the drawings

[0027] Figure 1 It is the electron micrograph of MNP / Cu-BTC MOF provided in Example 1 of the present invention;

[0028] Figure 2 It is the electron micrograph of exosomes provided in Example 2 of the present invention;

[0029] Figure 3 It is the analysis diagram related to the particle size and concentration of exosomes provided in Example 2 of the present invention;

[0030] Figure 4 It is the fluorescence spectrum of the capture of fluorescently labeled exosomes by MNP / Cu-BTC MOF provided in Example 3 of the present invention;

[0031] Figure 5 It is the laser confocal microscope of the capture of fluorescently labeled exosomes by MNP / Cu-BTC MOF provided in Example 3 of the present invention;

[0032] Figure 6 It is the fluorescence spectrum of the capture of fluorescently labeled exosomes by MNP / Cu-BTC MOF under different biological backgrounds provided in Example 3 of the present invention.

[0033] Figure 7This is the schematic diagram of the present invention. Detailed implementation mode

[0034] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the scope of the present invention.

[0035] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0036] Example 1

[0037] A preparation method of metal-organic framework MNP / Cu-BTC MOF includes the following steps:

[0038] Add 50 μL of an ethanol solution of MNPs (40 μg / mL) to 1 mL of BTC (0.125 M) dissolved in ethanol, and continuously stir. Then slowly add 1 mL of CuCl 2 (0.2 M) to the above solution to prepare a reaction solution with a total volume of 2 mL, and stir at room temperature for 0.5 h. Separate the prepared MNP / Cu-BTC MOF solution by magnetic separation for 5 min to separate the supernatant and precipitate. Wash the bottom precipitate with pure water three times to obtain the final product, dry it in a vacuum drying oven, and finally dissolve it in HEPES to obtain an MNP / Cu-BTC MOF solution with a concentration of 50 μg / mL. The electron micrograph of the finally prepared MNP / Cu-MOFs is as Figure 1 shown.

[0039] Example 2

[0040] A method for preparing fluorescently labeled exosomes includes the following steps:

[0041] Use a pipette to aspirate 5 mL of the culture supernatant of SK-BR-3 breast cancer cells (ATCC), and add 1.25 mL of Hieff TMThe Quick exosome extraction reagent was left standing at 4°C for 5 h; then the above mixture was centrifuged at 4°C and 10,000 rpm for 1 h, the bottom precipitate was collected, and resuspended in PBS buffer solution to a 2 mL EP tube; then centrifuged at 4°C and 14,000 rpm for 1 min. Take 99 μL of the above collected exosome solution and incubate it with 1 μL of Dil at low temperature for 15 min in the dark. Then the mixture was ultracentrifuged at 100,000 rpm and 4°C for 1 h, and the tube wall and the bottom precipitate were pipetted with PBS buffer solution to obtain the resuspended solution; the above fluorescently labeled exosome sample was placed in a dialysis bag and reacted overnight to remove the free Dil dye, and finally a pure fluorescently labeled exosome solution with a concentration of (1 - 3)×10 10 particles / mL, where the particles are the number of fluorescent dots. The electron microscopy image of the finally prepared exosomes is as shown in Figure 2 , and the nanoparticle tracking analysis results are as shown in Figure 3 (the concentration of the fluorescently labeled exosome solution was diluted to the E7 level, i.e., 10 7 ), which proves that exosomes with uniform particle size and distribution can be obtained according to the extraction and separation method.

[0042] Example 3

[0043] The steps to obtain a tumor-derived exosome catcher based on metal-organic framework are as follows:

[0044] Mix 45 μL of the 50 μg / mL MNP / Cu-BTC MOF solution prepared in Example 1 with 5 μL of the (1 - 3)×10 10 particles / mL fluorescently labeled exosome solution (i.e., the fluorescently labeled tumor-derived exosome solution in Example 2), incubate in the dark at room temperature for 15 min, perform magnetic sorting for 5 min, and resuspend the supernatant with HEPES buffer solution. As shown in Figure 4 , the maximum wavelength of the fluorescent dye in the supernatant was measured by a fluorescence spectrophotometer to obtain their respective fluorescence values. Compared with the initial fluorescence value, the fluorescence signal in the supernatant after magnetic sorting decreased significantly, corresponding to a capture rate of about 95.2% of the MNP / Cu-BTC MOF material for the fluorescently labeled exosomes; as shown in Figure 5 , the results of the laser confocal microscope showed that the bright field of MNP / Cu-BTC MOF almost completely overlapped with the Dil red fluorescence background. The above results verified the capture and adsorption effect of the above material on exosomes. Finally, different biological samples (such as DMEM, serum, plasma, and saliva) and HEPES buffer solution were added to the exosomes in the following Examples 4 - 8, and through the same magnetic sorting method, as shown in Figure 6 , the detection performance of MNP / / Cu-BTC MOF in these complex biological media was explored.

[0045] Example 4

[0046] A preparation method of a tumor-derived exosome catcher based on metal-organic framework is similar to Example 3. The difference is that in step (3), MNP / Cu-BTC MOF is incubated with exosomes added with biological sample - DMEM (Thermo Fisher), and effective adsorption of exosomes can still be achieved.

[0047] Example 5

[0048] A preparation method of a tumor-derived exosome catcher based on metal-organic framework is similar to Example 3. The difference is that in step (3), MNP / Cu-BTC MOF is incubated with exosomes added with biological sample - serum (human serum), and effective adsorption of exosomes can still be achieved.

[0049] Example 6

[0050] A preparation method of a tumor-derived exosome catcher based on metal-organic framework is similar to Example 3. The difference is that in step (3), MNP / Cu-BTC MOF is incubated with exosomes added with biological sample - plasma (human plasma), and effective adsorption of exosomes can still be achieved.

[0051] Example 7

[0052] A preparation method of a tumor-derived exosome catcher based on metal-organic framework is similar to Example 3. The difference is that in step (3), MNP / Cu-BTC MOF is incubated with exosomes added with biological sample - saliva (saliva of normal people), and effective adsorption of exosomes can still be achieved.

[0053] Example 8

[0054] A preparation method of a tumor-derived exosome catcher based on metal-organic framework is similar to Example 3. The difference is that in step (3), MNP / Cu-BTC MOF is incubated with exosomes added with biological sample - HEPES buffer (Aladdin), and effective adsorption of exosomes can still be achieved.

[0055] Example 9

[0056] A preparation method of a tumor-derived exosome catcher based on metal-organic framework is similar to Example 3. The difference is that the material MNP / Cu-BTC MOF is replaced with MNP / Fe-BTC MOF, and the preparation method of MNP / Fe-BTC MOF is the same as that of MNP / Cu-BTC MOF. Specifically: 1 mL of BTC (0.125 M) dissolved in ethanol is added to a solution containing MNPs (40 μg / mL), and continuous stirring is carried out. Then 1 mL of FeCl 3(0.2M) was slowly added to the above solution, and the mixture was stirred at room temperature for 0.5 h. The obtained precipitate was magnetically separated for 5 min, and the final product was washed three times with pure water. The maximum wavelength of the fluorescent dye in the supernatant was measured by a fluorescence spectrophotometer to obtain the respective fluorescence values. Compared with the initial fluorescence value, the fluorescence signal in the supernatant after magnetic separation decreased, corresponding to a capture rate of about 85.7% of the fluorescently labeled exosomes by the MNP / Fe-BTC MOF material; the coincidence effect of the bright field of the laser confocal microscopy MNP / Fe-BTC MOF and the Dil red fluorescence background was inferior to that of MNP / Cu-BTC MOF. Only anhydrous copper chloride CuCl 2 was replaced with FeCl 3 , and the adsorption of exosomes could be achieved, but the adsorption effect was inferior to that of MNP / Cu-BTC MOF.

[0057] Example 10

[0058] Similar to Example 3, except that the material was MNP / Zn-BTC MOF instead of MNP / Cu-BTC MOF, and the preparation method of MNP / Zn-BTC MOF was the same as that of MNP / Cu-BTC MOF. The maximum wavelength of the fluorescent dye in the supernatant was measured by a fluorescence spectrophotometer to obtain the respective fluorescence values. Compared with the initial fluorescence value, the fluorescence signal in the supernatant after magnetic separation decreased, corresponding to a capture rate of about 74.6% of the fluorescently labeled exosomes by the MNP / Zn-BTC MOF material; only partial overlap was observed between the bright field of the laser confocal microscopy MNP / Zn-BTC MOF and the Dil red fluorescence background, which was significantly inferior to that of MNP / Cu-BTC MOF. Only anhydrous copper chloride CuCl 2 was replaced with ZnCl 2 , and the adsorption of exosomes could be achieved, but the adsorption effect was inferior to that of MNP / Cu-BTC MOF.

[0059] Example 11

[0060] A preparation method of a tumor-derived exosome capturer based on metal-organic framework, similar to Example 3, except that the material was MNP / DA instead of MNP / Cu-BTC MOF. Preparation of MNPs-DA:

[0061] A solution of MNP (40 μg / mL) was incorporated into a Tris-HCl solution with a pH of 8.5, and after stirring, a dopamine solution was added to a final concentration of 1 mM. The reaction was carried out in the dark at 4 °C for 10 h. The obtained precipitate was magnetically separated for 5 min, and the final product was washed three times with pure water. It was found in the experiment that the material MNP / DA obtained in this example had a poor adsorption effect on exosomes.

[0062] The present invention discloses a tumor-derived exosome catcher based on metal-organic frameworks, where the metal-organic framework (MNP / Cu-BTC MOF) serves as the catcher, and exosomes derived from breast cancer cells (SK-BR-3) are used as the research object. The adsorption and capture of exosomes can be achieved through the interaction between metal ions in the metal-organic framework and the phospholipid structure on the tumor-derived exosomes.

[0063] The inventors' research found that if the metal framework model is not adopted, and similar literature reports, for example, using heavy-loaded cytometry to electroporate heavy metal ion reagents into exosomes to track exosomes at the single-cell level, the steps are cumbersome and the cost is expensive. The inventors also found that although other metal ions such as Fe 3+ , Zn 2+ etc. can also form MOF framework materials with MNP and BTC, their adsorption effects on tumor-derived exosomes cannot be compared with those of Cu 2+ . At the same time, the adsorption of metal ions on the surface of exosomes can be achieved through the metal-organic framework. By changing the structure of the material (such as MNP / Cu-BTC MOF), the effective adsorption of exosomes can still be achieved. However, if MNP / Cu-BTC MOF is replaced with other nanomaterials such as MNP / DA, the effective adsorption of tumor-derived exosomes cannot be achieved.

[0064] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention, and any reference signs in the claims should not be regarded as limiting the claimed rights.

Claims

1. A metal-organic framework MNP / Cu-BTC MOF with a rod-like morphology as a whole, an average diameter of 5-20 μm, and a length range of 80-160 μm, where Cu 2+ forms a rod-like skeleton structure Cu-BTC MOF with BTC, and the magnetic beads MNP are spherical and attached to the surface of the rod-like skeleton structure; the BTC is 1,3,5-benzenetricarboxylic acid, and the MNP is a superparamagnetic silica-coated magnetic bead.

2. A preparation method of metal-organic framework MNP / Cu-BTC MOF, which is to add BTC to MNP, then add copper chloride dihydrate, and react at room temperature; perform magnetic separation, washing, and drying; the molar ratio of BTC to copper chloride dihydrate is 1:1 - 3.

3. The preparation method according to claim 2, characterized in that, Add 10 - 50 μL of an ethanol solution of MNPs at 30 - 50 μg / mL to 1 mL of an ethanol solution of BTC at 0.1 - 0.2 M, stir continuously, and then slowly add 1 mL of a CuCl 2 solution to the mixed solution and stir at room temperature for 10 - 60 min.

4. The preparation method according to claim 3, characterized in that, Add 50 μL of a 40 μg / mL MNPs ethanol solution to 1 mL of a 0.125 M BTC ethanol solution, stir continuously, and then slowly add 1 mL of a 0.2 M CuCl 2 solution to the above solution and stir at room temperature for 30 min.

5. The application of the metal-organic framework MNP / Cu-BTC MOF described in claim 1 or obtained by the preparation method described in any one of claims 2 - 4 in the preparation of a tumor-derived exosome catcher.

6. The application according to claim 5, characterized in that, The tumor-derived exosomes are obtained through an exosome extraction kit and labeled with a fluorescent dye to prepare fluorescently labeled tumor-derived exosomes, and then the metal-organic framework MNP / Cu-BTC MOF is co-incubated with the fluorescently labeled tumor-derived exosomes.

7. The application according to claim 6, characterized in that, The method steps for preparing the fluorescently labeled tumor-derived exosomes are as follows: Collect the supernatant in the tumor cell culture flask into a test tube, and collect exosomes from tumor cells according to the extraction kit; incubate the extracted exosomes with a fluorescent dye to obtain fluorescently labeled exosomes; purify the fluorescently labeled exosomes by dialysis and store them in a -20 - -40 °C refrigerator.

8. The application according to claim 6, characterized in that, The application adopts the following step method: Co-incubate the metal-organic framework MNP / Cu-BTC MOF with the fluorescently labeled tumor-derived exosomes at room temperature, and determine its capture efficiency by fluorescence spectroscopy for biosensing analysis and detection.

9. The application according to claim 8, characterized in that, After the co-incubation at room temperature, it further includes the steps of magnetic separation, discarding the supernatant, and resuspending the precipitate.

10. The application according to claim 8, characterized in that, Incubate 5 μL of fluorescently labeled tumor-derived exosomes with 45 μL of a 50 μg / mL MNP / Cu-BTC MOFs solution in the dark at room temperature for 15 min, perform magnetic separation for 5 min, discard the supernatant, and resuspend with HEPES buffer solution to obtain a tumor-derived exosome catcher based on the metal-organic framework MNP / Cu-BTC MOF.

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