Exosome capture electrode, method of preparation and use

Abstract

The present application relates to the technical field of exosome, especially to an exosome capture electrode, a preparation method and application thereof, and is based on the principle that hydrophobic molecules can effectively insert into phospholipid bilayers to capture exosomes, and the hydrophobic molecules are directly modified on the surface of a working electrode, and then an exosome-containing solution is incubated with the working electrode, so that the exosomes in the solution can be captured on the surface of the working electrode. The method can directly capture exosomes on the surface of the working electrode, and is simple to operate without other enrichment procedures. In addition, the hydrophobic interaction cannot adsorb free proteins, and effectively avoids the interference of free proteins in the solution.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of exosome, in particular to an exosome capture electrode, a preparation method and application thereof. BACKGROUND

[0002] Exosome is a kind of cell-secreted phospholipid bilayer nanovesicle. The inside of exosome is rich in lipids, proteins, mRNA / miRNA and DNA fragments, and widely exists in body fluids such as urine, saliva, milk, blood and cerebrospinal fluid. Existing medical research shows that exosome plays an important role in physiology and pathology. When physiological conditions appear abnormal, the content and carried substances of exosome in the body will change accordingly according to the disease or its stage. Through quantitative analysis and detection of the number of specific exosomes and specific proteins or nucleic acids carried by the exosomes, the diagnosis and monitoring of diseases such as tumors, diabetes and nervous system related diseases can be effectively realized. At present, exosome has become an important detection object of liquid biopsy in clinic.

[0003] Existing research has developed a variety of quantitative detection methods for exosome. Common methods include surface enhanced Raman scattering (SERS), surface plasmon resonance (SPR), electrochemical method, colorimetric method and fluorescence method. Among them, the sensitivity of colorimetric method is low, fluorescence method involves long time and large equipment, surface enhanced Raman scattering needs expensive instruments, and the stability and test efficiency of surface plasmon resonance need to be improved. The main advantages of the detection method based on electrochemistry are low cost, high sensitivity and reliability, simple and fast, and easy to realize in small and automatic equipment for routine screening.

[0004] However, in the existing electrochemical detection method of exosome, the capture of exosome mainly adopts two strategies. One is to pre-enrich exosome by ultracentrifugation, immunomagnetic beads and other methods, and then detect the enriched exosome by electrochemical method. The other is to modify the antibody, peptide segment or nucleic acid aptamer molecule recognizing the surface protein of exosome on the electrode surface, and capture the exosome through the modified ligand molecule. In the above two strategies, the former needs to use large instrument equipment or complicated operation. The latter cannot effectively reduce the interference of free proteins (non-exosome membrane surface proteins) in the body fluid on the detection of exosome.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The purpose of the present application is to provide an exosome capture electrode loaded with hydrophobic molecules, so as to directly capture exosome on the surface of the working electrode, avoid additional enrichment procedures, and effectively avoid the interference of free proteins in the solution.

[0007] To solve the above technical problems, achieve the above purposes, the present application provides the following technical solutions.

[0008] In a first aspect, the present application provides an exosome capture electrode, which is an electrode with hydrophobic molecules loaded on the surface, the hydrophobic molecules containing long-chain alkanes with a carbon chain length greater than or equal to 17.

[0009] In an optional embodiment, the electrode is selected from a gold electrode, a glassy carbon electrode, a carbon paste electrode, a silver electrode, a zinc electrode, a platinum electrode, a palladium electrode, or a graphite electrode.

[0010] In an optional embodiment, the hydrophobic molecules include methyl stearate and / or distearoyl phosphatidyl ethanolamine.

[0011] In an optional embodiment, the connection of the exosome capture electrode and the hydrophobic molecules includes covalent bond chemical modification, electropolymerization, or physical adsorption.

[0012] In an optional embodiment, the exosome capture electrode further contains a connecting molecule connecting the exosome capture electrode and the hydrophobic molecules.

[0013] Preferably, the electrode is a gold electrode, the hydrophobic molecules are distearoyl phosphatidyl ethanolamine, and the connecting molecule is a thiol-modified polyethylene glycol, the thiol group being connected to the gold electrode, and the polyethylene glycol being connected to the amino terminal of the distearoyl phosphatidyl ethanolamine.

[0014] In a second aspect, the present application provides a preparation method of the exosome capture electrode of the foregoing embodiments, in which stearoyl phosphatidyl ethanolamine-polyethylene glycol-thiol is loaded on the surface of a gold electrode by using Au-S bond.

[0015] Preferably, the gold electrode is polished before the loading reaction.

[0016] Preferably, the gold electrode is subjected to potential cycle activation after polishing before the loading reaction.

[0017] Preferably, the potential cycle activation includes cyclic voltammetry scanning of the gold electrode in a sulfuric acid aqueous solution in the range of 0.1V-1.2V.

[0018] Preferably, the distearoyl phosphatidyl ethanolamine-polyethylene glycol-thiol is activated by tris(2-chloroethyl) phosphate before the loading reaction.

[0019] Preferably, the tris(2-chloroethyl) phosphate activation includes incubation of the distearoyl phosphatidyl ethanolamine-polyethylene glycol-thiol and tris(2-chloroethyl) phosphate at 4℃.

[0020] Preferably, the concentration of the tris(2-chloroethyl) phosphate is 10mM.

[0021] Preferably, the length of the incubation is 1 h.

[0022] In an alternative embodiment, the hydrophobic molecule is at a concentration of 0.1-200 μM under light-protected conditions. Two The stearoyl phosphatidylethanolamine-polyethylene glycol-thiol is self-assembled on the surface of a gold electrode to achieve loading.

[0023] In an alternative embodiment, the loading reaction temperature is 4℃ and the reaction time is 12 h.

[0024] In a third aspect, the present application provides the use of the exosome capture electrode of any one of the preceding embodiments or the exosome capture electrode obtained by the preparation method of any one of the preceding embodiments in any one of (a)-(e):

[0025] (a) exosome enrichment;

[0026] (b) exosome purification;

[0027] (c) exosome species identification;

[0028] (d) exosome number measurement;

[0029] (e) exosome cargo measurement.

[0030] In an alternative embodiment, the exosomes are non-specific phenotype exosomes.

[0031] The present application is based on the principle that hydrophobic molecules can effectively insert into the phospholipid bilayer, thereby capturing exosomes. The hydrophobic molecules are directly modified on the surface of the working electrode, and the solution containing exosomes is incubated with the working electrode, so that the exosomes in the solution can be captured on the surface of the working electrode. This method can directly capture exosomes on the surface of the working electrode, and is simple to operate without the need for other enrichment procedures. In addition, this hydrophobic interaction does not adsorb free proteins, effectively avoiding the interference of free proteins in the solution. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0033] Figure 1 Schematic diagram of the principle of capturing exosomes by the hydrophobic molecule-loaded electrode in Example 1;

[0034] Figure 2Figure for scanning electron microscope (SEM) characterization results of exosomes after incubation of non-loaded hydrophobic molecule electrodes (A, B) and loaded hydrophobic molecule electrodes (C, D) in Example 1;

[0035] Figure 3 Figure for electrochemical performance characterization of loaded hydrophobic molecule electrodes in Example 1;

[0036] Figure 4 Figure for electrochemical signal response results of different concentrations of exosomes detected by loaded DSPE gold electrode in Example 2;

[0037] Figure 5 DSPE modified gold electrode for detecting exosomes and CD63 protein on the surface of exosomes;

[0038] Figure 6 DSPE modified gold electrode for detecting Her2 protein on the surface of clinical blood exosomes;

[0039] Figure 7 Effect of plasma free protein on the results of exosome detection and CD63 protein on the surface of exosomes by DSPE modified gold electrode. DETAILED DESCRIPTION

[0040] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application.

[0041] In a specific embodiment, in a first aspect, the present application provides an exosome capture electrode, wherein the exosome capture electrode is an electrode loaded with a hydrophobic molecule on the surface, and the hydrophobic molecule contains a long-chain alkane, and the carbon chain length of the alkane is greater than or equal to 17.

[0042] In an optional embodiment, the electrode is selected from a gold electrode, a glassy carbon electrode, a carbon paste electrode, a silver electrode, a zinc electrode, a platinum electrode, a palladium electrode or a graphite electrode.

[0043] In an optional embodiment, the hydrophobic molecule includes at least one of methyl stearate and / or distearoyl phosphatidyl ethanolamine.

[0044] In an optional embodiment, the connection mode of the exosome capture electrode and the hydrophobic molecule includes covalent bond chemical modification, electropolymerization or physical adsorption.

[0045] In an optional embodiment, the exosome capture electrode further contains a connecting molecule connecting the exosome capture electrode and the hydrophobic molecule.

[0046] Preferably, the electrode is a gold electrode, the hydrophobic molecule is distearoylphosphatidylethanolamine, the linking molecule is a thiol-modified polyethylene glycol, the thiol is connected to the gold electrode, and the polyethylene glycol is connected to the amino-terminus of the distearoylphosphatidylethanolamine.

[0047] In a second aspect, the present application provides a method for preparing the exosome capture electrode according to any of the preceding embodiments, wherein the distearoylphosphatidylethanolamine-polyethylene glycol-thiol is loaded on the surface of the gold electrode by Au-S bond.

[0048] Preferably, the gold electrode is polished before the loading reaction.

[0049] Preferably, the gold electrode is subjected to potential cycling activation after polishing before the loading reaction.

[0050] Preferably, the potential cycling activation comprises cyclic voltammetry scanning of the gold electrode in aqueous sulfuric acid solution at a range of 0.1 V to 1.2 V.

[0051] Preferably, the distearoylphosphatidylethanolamine-polyethylene glycol-thiol is activated by tris(2-chloroethyl)phosphate before the loading reaction.

[0052] Preferably, the tris(2-chloroethyl)phosphate activation comprises incubation of the distearoylphosphatidylethanolamine-polyethylene glycol-thiol with tris(2-chloroethyl)phosphate at 4°C.

[0053] Preferably, the concentration of the tris(2-chloroethyl)phosphate is 10 mM.

[0054] Preferably, the incubation lasts for 1 h.

[0055] In an alternative embodiment, the loading is achieved by self-assembly of the distearoylphosphatidylethanolamine-polyethylene glycol-thiol on the surface of the gold electrode under light-protected conditions at a concentration of 0.1-200 μM.

[0056] In an alternative embodiment, the loading reaction is carried out at 4°C for 12 h.

[0057] In a third aspect, the present application provides the use of the exosome capture electrode according to any of the preceding embodiments or obtained by the method according to any of the preceding embodiments in any of the following (a)-(e):

[0058] (a) exosome enrichment;

[0059] (b) exosome purification;

[0060] (c) exosome species identification;

[0061] (d) exosome number measurement;

[0062] (e) exosome cargo measurement.

[0063] The exosome cargo refers to the proteins and nucleic acids carried by the exosome.

[0064] In an alternative embodiment, the exosome is a non-specific phenotype exosome.

[0065] In some embodiments, during the enrichment, purification or identification of the exosome, the exosome is detected by electrochemical method. The detection method comprises: taking a certain volume of solution containing exosomes, incubating the solution with a capture electrode, then washing the electrode, detecting the electrical signal by an electrochemical workstation to measure the content of the exosome. Then, the electrode with the captured exosome is incubated with a probe molecule that recognizes the surface protein of the exosome, and then the electrode is washed to remove the free probe molecule. The detection of the electrical signal intensity of the probe molecule by the chemical workstation can achieve the detection of the surface protein of the exosome.

[0066] Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The following examples and features in the examples can be combined with each other without conflict.

[0067] Example 1

[0068] The present embodiment provides a preparation method of an exosome capture probe, and the specific steps are as follows:

[0069] 1.1 electrode pretreatment

[0070] (1) The gold electrode has good electrical conductivity, and is used as the working electrode in the present embodiment. A bare gold electrode with a diameter of 2.0 mm is polished on a polishing cloth containing polishing mud. The main component of the polishing powder is aluminum oxide (Al2O3) with a particle size of 50 nm. The polishing is performed to mirror finish to ensure good electrochemical performance in subsequent experiments.

[0071] (2) The surface of the gold electrode is first rinsed with ultrapure water to remove residual aluminum oxide, and then ultrasonic treatment is performed in ultrapure water, ethanol and ultrapure water in sequence to further remove the aluminum oxide;

[0072] (3) The electrode is electrochemically pretreated by using an electrochemical workstation to perform potential cycling in a 0.5 mol / L H2SO4 aqueous solution at a scan rate of 100 mV·s -1 -1.5 V until the cyclic voltammogram characteristic of a pure gold electrode is obtained;

[0073] (4) The gold electrode is thoroughly washed with a large amount of ultrapure water and dried under nitrogen.

[0074] 1.2 Preparation of capture electrode loaded with hydrophobic molecules

[0075] Distearoyl phosphatidyl ethanolamine (DSPE) contains long-chain alkane structure, which is a kind of 18-carbon saturated phospholipid with high hydrophobicity. It has good hydrophobic molecules and can insert into the phospholipid bilayer of exosomes to capture exosome molecules. The polyethylene glycol (PEG) molecule is connected to the amino terminal of the DSPE molecule through an amidation reaction, which increases the distance between the DSPE molecule and the electrode surface, thereby enhancing the interaction between the DSPE molecule on the modified electrode surface and the exosome phospholipid bilayer. Finally, the thiol group is modified at the end of the PEG molecule. In this embodiment, DSPE-PEG-SH is purchased from Shenzhen Meiluosheng Technology Co., Ltd. with the product number 060504-3A, and then the DSPE-PEG molecule is modified on the gold electrode surface by using the Au-S bond. During the loading process, TCEP is first used to activate DSPE, the purpose is to cut the disulfide bond formed between molecules. The activated DSPE-PEG-SH (1.0 μM, 20 μL) is added dropwise on the activated gold electrode surface, and incubated at 4°C in the dark for 12 h, and self-assembled by using the Au-S bond. Then use 1% concentration of Tween 20 reagent to ultrasonic cleaning for 20 min, and prepare the DSPE capture electrode. The capture process is shown in Figure 1 , and the scanning electron microscope results of the DSPE-loaded gold electrode capturing exosomes are shown in Figure 2 .

[0076] Electrochemical impedance spectroscopy (EIS) is an effective electrochemical method and is widely used to characterize the modification and assembly process of electrochemical sensors. In this embodiment, 5 mmol / L K3[Fe(CN)6] / K4[Fe(CN)6] in 0.1 mol / L KCl aqueous solution is used to measure the electrochemical impedance of the gold electrode without loading hydrophobic molecules, the DSPE-loaded gold electrode without capturing exosomes, and the DSPE-loaded gold electrode capturing exosomes (incubation time is 30 min), respectively. The measurement frequency range is 0.1-100 kHz, the bias potential is 0.327 V, and the alternating current amplitude is 5 mV. The results are shown in Figure 3 , and Figure 3 , where A is the cyclic voltammetry (CV) scan result graph of the electrode after different treatments; B is the electrochemical impedance spectroscopy (EIS) scan result graph of the electrode after different treatments. As can be seen from the figure, after the DSPE is loaded on the electrode surface, the electron transfer ability is weakened, the resistance is increased, and the diameter of the semicircle in the impedance spectrum is increased. After the electrode captures the exosomes, the lipid bilayer and proteins on the surface of the exosomes inhibit the redox reaction of the redox probe [Fe(CN)6] 3- / 4- , resulting in a decrease in current intensity and an increase in semicircle diameter. The above results show that the exosomes are successfully captured by the modified electrode.

[0077] Example 2

[0078] This embodiment uses the capture electrode loaded with hydrophobic molecules provided in Example 1 for exosome detection, specifically including the following steps:

[0079] Take 3 mL of mouse plasma, dilute 5 times, and perform ultracentrifugation at 100,000 g for 70 min. Remove the supernatant after centrifugation twice, and resuspend in 200 mL of DPBS to obtain exosomes. The nanoparticle tracking analysis (NTA) technique is used to measure the concentration of exosomes. Phosphate buffer is used to prepare exosome solutions with concentrations of 0, 10 5 ,10 6 ,10 7 ,10 8 ,10 9 ,10 10 ,10 11 μL of the exosome solution is dropped onto the DSPE-loaded electrode, and incubated at 4°C in the dark for 30 min. Differential pulse voltammetry (DPV) is measured using an electrochemical workstation in 0.1 mol / L KCl electrolyte containing 5 mmol / L K3[Fe(CN)6] / K4[Fe(CN)6]. The scan range is -0.2-0.8 V, the scan rate is 50 mV·s -1 , and the step potential is 4 mV. The scanning results are shown in A of Figure 4 . The higher the concentration of exosomes, the smaller the current signal. This is because the exosomes on the electrode surface hinder the electron transfer, inhibit the redox reaction of the redox probe [Fe(CN)6] 3- / 4- , and the current decreases with the increase of the concentration of exosomes. The DPV current of the electrode incubated with phosphate buffer with a concentration of 0 is taken as the background signal, and the relative DPV peak current signal of the DSPE-modified electrode after incubation with exosome solutions at different concentrations is calculated, and the curve is drawn, as shown in B of Figure 4 . It can be seen that the DPV peak current signal of the electrode after treatment with exosomes at different concentrations is linearly related to the logarithm of the concentration of exosomes, the linear range is 10 6 -10 10 μL, and the detection limit LOD is 1.98 x 10 5 μL. The results show that the DSPE-modified electrode has strong ability to detect exosomes, and has a wide linear range.

[0080] Example 3

[0081] This embodiment uses the capture electrode loaded with hydrophobic molecules provided in Example 1 for specific identification of the exosome epitope antigen CD63 protein, specifically including the following steps:

[0082] Phosphate buffer is used to prepare exosome solutions with concentrations of 0, 10 3 ,104 10 5 10 6 10 7 10 8 10 9 Exosome solution (exosome acquisition method as described in Example 1) was prepared by taking 20 μL of each solution and dropwise onto a DSPE-modified electrode. The electrode was then incubated at 4°C in the dark for 30 min, followed by washing three times with 1 mL of phosphate buffer. Separately, 32 pmol of the methylene blue-modified aptamer apCD63-MB, which recognizes CD63 protein, was dissolved in 160 μL of incubation solution (1% BSA, 1% tRNA, 5 mM MgCl2 phosphate buffer). The solution was denatured at 95°C for 5 min, cooled on ice for 10 min, and 20 μL was dropwise onto the surface of the exosome-modified electrode. The electrode was then incubated at 4°C in the dark for 40 min. The electrode was then placed in phosphate buffer for electrochemical detection of the methylene blue signal. In this case, square wave voltammetry (SWV) was used. The potential scan range was -0.8 to -0.4 V, the potential step was 4 mV, the amplitude was 25 mV, and the frequency was 15 Hz. The results are as follows: Figure 5 As shown in the figure, A is the electrochemical signal response of methylene blue measured after capturing different concentrations of exosomes with the DSPE-modified electrode and incubating the CD63-MB probe, and B is the fitting curve of the logarithm of the exosome concentration and the measured relative peak current signal. It can be seen that the methylene blue signal detected by the DSPE-modified electrode after incubation with different concentrations of exosomes increases with increasing exosome concentration. The logarithm of the exosome concentration shows a linear relationship with the SWV signal peak current, with a linear range of 10. 4 -10 9 The detection limit (LOD) was 1.32 × 10⁻⁶ cells / mL. 3 The concentration of exosomes per mL indicates that the prepared sensor, after the addition of CD63 nucleic acid aptamer, can quantitatively detect exosome surface protein signals, and the detection sensitivity and linear range of exosomes are also significantly improved.

[0083] The nucleotide sequence of the apCD63-MB is (SEQ ID No. 1): 5'-CACCCCACCTCGCTCCCGTGACACTAATGCTATTTTTT-methylene blue-3'.

[0084] Example 4

[0085] This embodiment uses the capture electrode loaded with hydrophobic molecules provided in Example 1 for the specific identification of the exosome epitope antigen Her2 protein, specifically including the following steps:

[0086] Take 5 μL of plasma from breast cancer patients and healthy individuals, dilute 4 times with phosphate buffer, drop on the DSPE-loaded electrode, incubate at 4°C in the dark for 30 min, wash the electrode in 1 mL of phosphate buffer solution for 3 times. Take another 32 pmol of methylene blue modified aptamer apHer2-MB that recognizes Her2-protein, dissolve in 160 μL of incubation solution (1% BSA, 1% tRNA, 5 mM MgCl2 phosphate buffer), denature at 95°C for 5 min, cool on ice for 10 min, take 20 μL, drop on the surface of the modified electrode incubated with exosomes, incubate at 4°C in the dark for 40 min. Then place the electrode in phosphate buffer solution for electrochemical detection of methylene blue signal. This example uses square wave voltammetry (SWV) scanning, the potential scanning range is: -0.8 to -0.4 V, the potential step is 4 mV, the amplitude is 25 mV, the frequency is 15 Hz, and the detection result is shown in Figure 6 Fig. 6. The methylene blue signal of the nucleic acid aptamer apHer2-MB is detected by the DSPE-modified electrode after plasma incubation, and the Her2 protein signal on the surface of exosomes in the blood of breast cancer patients is significantly stronger than that of healthy individuals. The conclusion shows that the prepared sensor with Her2 nucleic acid aptamer can detect the Her2 protein on the surface of exosomes, and can be used for the diagnosis of breast cancer disease in clinical samples.

[0087] The nucleotide sequence of apHer2-MB (SEQ ID No. 2) is 5'-methylene-GGGCCGTCGAACACGAGCATGGTGCGTGGACCTAGGATGACCTGAGTACTGTCC-3'.

[0088] Example 5:

[0089] This example uses the capture electrode loaded with hydrophobic molecules provided in Example 1 for specific identification of exosome epitope antigen CD63 protein, and studies the anti-free protein interference performance in complex system, which specifically includes the following steps:

[0090] Use 20% mouse plasma protein (not containing exosomes, which is the supernatant protein solution extracted from mouse plasma ultracentrifugation for exosomes) and phosphate buffer to prepare 0, 10 3 ,10 4 ,10 5 ,10 6 ,10 7 ,10 8 ,10 9Exosome solution (see Example 1 for exosome preparation) at 1 μg / mL was taken 20 μL respectively, and dropped on the DSPE modified electrode. The electrode was incubated at 4℃ for 30 min in dark, and then washed with 1 mL phosphate buffer solution for 3 times. 32 pmol methylene blue modified aptamer apCD63-MB recognizing CD63 protein was dissolved in 160 μL incubation solution (1% BSA, 1% tRNA, 5 mM MgCl2 phosphate buffer solution), denatured at 95℃ for 5 min, and cooled on ice for 10 min. 20 μL of the solution was dropped on the electrode surface incubated with exosome, and incubated at 4℃ for 40 min in dark. Then the electrode was placed in phosphate buffer solution for electrochemical detection of methylene blue signal. Square wave voltammetry (SWV) was used for scanning, with potential scanning range of -0.8 to -0.4 V, potential step of 4 mV, amplitude of 25 mV, and frequency of 15 Hz. The results are shown in Figure 7 Figure 3, and the signal intensity of exosome prepared in 20% mouse plasma and phosphate buffer solution was compared. It was found that the signal intensity was roughly the same, and the anti-free protein interference performance was good. This indicates that free proteins in complex system will not affect the performance of the sensor, and solves the problem of free protein interference in the capture of exosome by antibody or aptamer in the literature report. Therefore, the detection method provided in the present experiment is feasible in complex biological sample environment.

[0091] The nucleotide sequence of the apCD63-MB is (SEQ ID No. 1): 5'-CACCCCACCTCGCTCCCGTGACACTAATGCTATTTTTT-methylene blue-3'.

[0092] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An exosome capture electrode, characterized by, The exosome capture electrode is an electrode with surface loading of hydrophobic molecules, the hydrophobic molecules containing long-chain alkanes, the alkanes having a carbon chain length greater than or equal to 17. The hydrophobic molecules include methyl stearate and / or distearoyl phosphatidyl ethanolamine.

2. The exosome capture electrode of claim 1, wherein, The electrode is selected from a gold electrode, a glassy carbon electrode, a carbon paste electrode, a silver electrode, a zinc electrode, a platinum electrode, a palladium electrode or a graphite electrode.

3. The exosome capture electrode according to claim 1 or 2, characterized in that, The connection of the exosome capture electrode and the hydrophobic molecules includes covalent bond chemical modification, electro-polymerization or physical adsorption.

4. The exosome capture electrode of claim 1, wherein, The exosome capture electrode further contains a connecting molecule connecting the exosome capture electrode and the hydrophobic molecules.

5. The exosome capture electrode of claim 4, wherein, The electrode is a gold electrode, the hydrophobic molecules are distearoyl phosphatidyl ethanolamine, the connecting molecule is a thiol-modified polyethylene glycol, the thiol group is connected to the gold electrode, and the polyethylene glycol is connected to the amino terminal of the distearoyl phosphatidyl ethanolamine.

6. The method of claim 5, wherein the exosome capture electrode is prepared by, The preparation method includes loading the hard distearoyl phosphatidyl ethanolamine-polyethylene glycol-thiol on the surface of the gold electrode by using Au-S bond.

7. The production method according to claim 6, wherein The gold electrode is polished before the loading reaction.

8. The preparation method according to claim 7, characterized in that, The gold electrode is subjected to potential cycle activation after polishing before the loading reaction.

9. The production method according to claim 8, characterized by, The potential cycle activation includes cyclic voltammetry scanning of the gold electrode in a sulfuric acid aqueous solution in the range of 0.1V-1.2V.

10. The method of claim 6, wherein, The preparation method includes activating the distearoyl phosphatidyl ethanolamine-polyethylene glycol-thiol by tris(2-chloroethyl) phosphate before the loading reaction.

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