Miniature electrochemical sensor for detecting amyloid polypeptide A beta1-42 as well as preparation method and application of miniature electrochemical sensor

Abstract

The invention discloses a micro electrochemical sensor for detecting amyloid polypeptide A beta 1-42 as well as a preparation method and application of the micro electrochemical sensor. The specific preparation method comprises the following steps: taking an acupuncture needle as a bare electrode; the preparation method comprises the following steps: sequentially modifying tetrachloroauric acid trihydrate-gold nanoparticles, a single-walled carbon nanotube, heme, amyloid polypeptide A beta 1-42 template molecules, mixed polydopamine and an imprinted polymer formed by ionic liquid on the surface of a sample, and then eluting to obtain the ANME / / hemin / / SMIP electrode of the micro electrochemical sensor. The micro electrochemical sensor disclosed by the invention can be used for high-sensitivity detection of the amyloid polypeptide A beta 1-42, and specific detection of the amyloid polypeptide A beta 1-42 is realized.

Description

Technical Field

[0001] The present invention belongs to the field of electrochemical technology and specifically relates to a method for detecting amyloid peptide Aβ 1-42 Micro electrochemical sensor and its preparation method and application. Background Art

[0002] β-amyloid peptides are able to affect presynaptic release of hippocampal neurons and have been found to be the main component of senile plaques. Aβ is composed of amino acid residues produced after proteolytic cleavage of amyloid precursor protein by β- and γ-secretases. Excess Aβ oligomers can self-aggregate due to hydrophobic interactions and the self-recognition site of Leu17-Ala21. Regular β-folded structures are key pathogenic species that may lead to neuronal death, synaptic abnormalities, oxidative damage, inflammation, and accelerate disease progression. Aβ 1-42 It is the most important biomarker in the dynamic changes of Alzheimer's disease course.

[0003] Currently, there are many technologies that can detect Aβ 1-42 , including enzyme-linked immunosorbent assay, capillary isoelectric focusing, scanning tunneling microscopy, magnetic resonance imaging, surface plasmon resonance, positron emission tomography, fluorescence microscopy, and electrochemical analysis. Among them, electrochemical sensors have attracted much attention due to their high sensitivity, freedom from sample turbidity, and the intrinsic electronic properties of the substance. Electrodes are the basic components of electrochemical performance. Acupuncture needles are a traditional medical device and a new medical device developed in recent years. Microelectrodes are various shapes, smaller than ordinary planar electrodes and longer than other microelectrodes. Importantly, acupuncture needle microelectrodes can serve as suitable detectors for implantable non-destructive sensors and have the potential to be combined with mature acupuncture technology.

[0004] Molecularly imprinted polymers, known as "artificial antibodies," are promising recognition elements because they provide highly specific complementary binding sites and shapes for specific templates in a cross-linked polymer network. Molecularly imprinted polymers have unique advantages such as easy synthesis, simplicity, rapid recognition, high stability, low cost, and good selectivity. In recent years, surface imprinting technology for preparing thin layers of MIP (molecularly imprinted polymer) on a substrate has been developed. Since most of the template molecules are located on or near the surface of the material, surface molecularly imprinted polymers are expected to confer some significant advantages to electrochemical sensors, including low signal background, fast binding kinetics, and good anti-interference ability. At the same time, in situ electropolymerization is an effective method for the preparation of SMIP (surface molecularly imprinted polymer) microelectrodes, and it is also easy to provide suitable nanocavities for the smooth transfer of electrons. Application of surface molecular imprinting technology to amyloid peptide Aβ 1-42 The detection has important scientific significance and commercial value. Summary of the invention

[0005] In view of the above problems, the present invention aims to provide a method for detecting amyloid peptide Aβ 1-42 Micro electrochemical sensors and their preparation methods and applications. A microelectrochemical sensor for amyloid peptide Aβ was prepared on acupuncture needle electrodes by in situ electropolymerization and self-assembly technology. 1-42 SMIP. Heme is embedded under the SMIP layer, and current can smoothly pass through the imprinted nanocavities. In addition, recombinant amyloid peptide Aβ 1-42 The developed microsensor showed sensitive and selective detection of amyloid peptide Aβ 1-42 Capabilities of biomarkers.

[0006] The specific technical solutions are as follows:

[0007] A method for detecting amyloid peptide Aβ 1-42 The preparation method of the micro electrochemical sensor comprises the following steps:

[0008] 1) Pretreatment of acupuncture needles: grinding and polishing the acupuncture needles, ultrasonic cleaning, and drying the acupuncture needles for standby use;

[0009] 2) Modification of gold nanoparticles: The acupuncture needle pretreated in step 1) is used as a working electrode, and the tip of the acupuncture needle is immersed in a HAuCl4 solution containing KCl, and a cyclic voltammetry scan is performed. The obtained electrode is recorded as ANME / AuNPs;

[0010] 3) Modification of single-walled carbon nanotubes: The ANME / AuNPs electrode obtained in step 2) was used as a working electrode and electropolymerized in an aqueous solution containing 3,4-ethylenedioxythiophene and single-walled carbon nanotubes. After the polymerization was completed, the modified electrode was thoroughly washed with water and dried. The prepared electrode was marked as

[0011] ANME / AuNPs / SWNT;

[0012] 4) Heme modification: The ANME / AuNPs / SWNT electrode prepared in step 3) was immersed in a heme solution and incubated at 4°C to 25°C to obtain an electrode labeled

[0013] ANME / AuNPs / SWNT~hemin;

[0014] 5) Binding of template molecules: The electrode prepared in step 4) is immersed in Aβ 1-42 Solution at 25°C

[0015] Incubate at 37°C;

[0016] 6) Modification of the imprinted polymer membrane: using the electrode treated in step 5) as the working electrode, electropolymerizing dopamine and the ionic liquid by cyclic voltammetry scanning;

[0017] 7) Elution of template molecules: The encapsulated amyloid peptide Aβ treated in step 6) is washed with water. 1-42 The template is eluted to obtain the surface molecular imprinted microsensor

[0018] ANME / AuNPs / SWNT~hemin~Aβ@SMIP.

[0019] Furthermore, the specific operation process of step 1) is: grinding and polishing the acupuncture needles, ultrasonically cleaning them in ethanol and deionized water respectively, and then drying the acupuncture needles with nitrogen for later use.

[0020] Furthermore, in step 2), the scanning rate of the cyclic voltammetry scan is 25-100 mV / s, the potential range alternates between -1.5 V and 0.5 V, the scan is performed for 5-10 cycles, the concentration of the HAuCl4 solution is 2.5 mmol / L, and the 5-10 mm needle tip portion is immersed in the HAuCl4 solution containing KCl.

[0021] Furthermore, in step 3), the potential of the polymerization process is set to 1-1.2 V, the polymerization time is 100-200 seconds, the concentration of the 3,4-ethylenedioxythiophene solution is 0.01-0.02 mol / L, and the concentration of the single-walled carbon nanotube solution is 0.3-0.5 mol / L.

[0022] Furthermore, the solvent of the heme solution in step 4) is sodium hydroxide, the concentration is 3 to 5 mM, and the incubation time is 6 to 12 hours.

[0023] Furthermore, in step 5), Aβ 1-42 Solution is Aβ 1-42 Aβ was dissolved in 0.1 M PBS. 1-42 The solution concentration is 10-40 μM, and the incubation time is 30-60 min.

[0024] Furthermore, in step 6), the potential range of the electropolymerization is -0.5 to 0.5 V, the scan rate is 50 to 100 mV / s, the cycle scan is 10 to 20 times, and the electrolyte is 0.01 M PBS, pH = 7.4, containing 5 to 8 mM dopamine and 20 to 25 mM ionic liquid.

[0025] Furthermore, the elution process of step 7) is to elute the encapsulated amyloid peptide Aβ 1-42 The template was eluted with a PBS solution containing methanol for 60 to 120 minutes, with the volume ratio of methanol to PBS being 1:20.

[0026] A method for detecting amyloid peptide Aβ prepared by the above preparation method 1-42 Micro electrochemical sensor.

[0027] A method for detecting amyloid peptide Aβ 1-42 Application of micro electrochemical sensors.

[0028] The beneficial effects of the present invention are:

[0029] 1) The present invention uses cyclic voltammetry scanning during the deposition process, which is more conducive to the deposition of gold on the surface of the acupuncture needle electrode, and the distribution is more uniform and dense, presenting a spherical structure, providing more contact area for subsequent modification of the acupuncture needle electrode. The metal structure increases the contact area between the metal layer and the amyloid peptide Aβ after the imprinted electrode is eluted to form a cavity. 1-42 The increased contact surface area enhances the efficiency of electron transfer of hemoglobin on the electrode, effectively improving the electrocatalytic performance of the electrode;

[0030] 2) The present invention first electropolymerizes single-walled carbon nanotubes before combining hemin. Single-walled carbon nanotubes have excellent conductivity and can significantly improve the electron transfer efficiency of heme. After the heme molecules are combined with the polymerized single-walled carbon nanotubes, the rapid transfer of electrons can be promoted, thereby enhancing the electrocatalytic performance; the single-walled carbon nanotubes have a large surface area and can provide more binding sites, which facilitates the adsorption and stabilization of heme molecules on the surface; the combination of heme on SWNTs not only improves its stability, but also prolongs the life of the sensor prepared therefrom.

[0031] 3) The present invention selects heme as the built-in signal probe, which has the advantages of high sensitivity, stability, anti-interference ability, simple preparation and low cost. This makes it an ideal choice in molecular imprinting electrochemical sensors, especially suitable for detecting non-electroactive target molecules (such as amyloid peptide Aβ 1-42 ) and significantly improve the performance of the sensor.

[0032] 4) The present invention uses stainless steel acupuncture needles as sensor substrates, which are small in size, low in cost, and simple in preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Scanning electron microscopy images of bare acupuncture needle electrodes and ANME / AuNPs;

[0034] Figure 2 is the cyclic voltammogram during the stepwise modification process;

[0035] Figure 3 Cyclic voltammogram of the step-by-step modified electrode in PBS solution at pH = 7;

[0036] Figure 4The differential pulse voltammogram of the step-by-step modified electrode in PBS pH=7 solution;

[0037] Figure 5 The prepared micro electrochemical sensor is used to detect the amyloid peptide Aβ with different concentrations 1-42 Differential pulse voltammogram of the solution tested;

[0038] Figure 6 Microelectrochemical sensor prepared for the detection of amyloid peptide Aβ 1-42 During the test, ΔI(I1-I2) and amyloid peptide Aβ 1-42 Linear relationship graph of logarithmic concentration (1gC);

[0039] Figure 7 Preparation of micro-electrochemical sensor for binding amyloid peptide Aβ 1-42 and the response results after nonspecific molecules;

[0040] Figure 8 The non-molecular imprinting electrochemical biosensor prepared in Comparative Example 1 before elution, after elution and after rebinding to amyloid peptide Aβ 1-42 Differential pulse voltammogram after .

[0041] Fig. 9 CV graphs of electrodes with and without single-walled carbon nanotube modification;

[0042] Fig.10 DPV images of electrodes with and without single-walled carbon nanotube modification. DETAILED DESCRIPTION

[0043] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but the protection scope of the present invention is not limited thereto.

[0044] Example 1

[0045] A method for detecting amyloid peptide Aβ 1-42 The preparation method of the micro electrochemical sensor comprises the following steps:

[0046] 1) Pretreatment of acupuncture needles: polish the acupuncture needles, ultrasonically clean them in ethanol and deionized water for 5 minutes respectively, and then dry the acupuncture needles with nitrogen for later use. Scan the bare acupuncture needle electrodes with an electron microscope, such as Figure 1 As shown in A, only longitudinal scratches appear after polishing;

[0047] 2) Modification of gold nanoparticles: The pretreated acupuncture needle electrode was used as the working electrode, the saturated calomel electrode was used as the reference electrode, and the platinum wire electrode was used as the counter electrode. The 5 mm tip of the acupuncture needle electrode was immersed in a solution containing 2.5 mM HAuCl4 and 0.1 M KCl. Five cycles were scanned at a scanning rate of 25 mV·s-1, and the potential was alternately changed between -1.5 V and 0.5 V. The obtained electrode was labeled as ANME / AuNPs. The electrode was scanned by electron microscope, as shown in FIG. Figure 1 As shown in B, after modification with gold nanoparticles, AuNPs aggregate together to form a rough surface; it can be observed that the particle size distribution of AuNPs is uniform, ranging from 80 to 160 nm;

[0048] 3) Modification of single-walled carbon nanotubes: Electropolymerization was performed in 5.00 mL of aqueous solution containing 3,4-ethylenedioxythiophene (the concentration in aqueous solution was 0.02 M) and 20 mg of single-walled carbon nanotubes (SWNTs). The potential of the polymerization process was set to 1.2 V, and the polymerization time was 100 seconds. After the polymerization was completed, the modified electrode was thoroughly washed with water and dried. The prepared electrode was labeled as ANME / AuNPs / SWNT.

[0049] 4) Heme modification: ANME / AuNPs / SWNT was immersed in 3 mM heme (dissolved in 200 mM NaOH) and incubated at 4 °C for 12 h to obtain ANME / AuNPs / SWNT~hemin (abbreviated as ANME / / hemin).

[0050] 5) Binding of template molecules: The prepared electrode was immersed in 40 μM Aβ 1-42 solution (dissolved in 0.1 M PBS, pH = 7.5), incubated at 37 ° C for 30 minutes, and recorded as ANME / AuNPs / SWNT~hemin~Aβ 1-42 ;

[0051] 6) Modification of the imprinted polymer membrane: Dopamine and ionic liquid were electropolymerized by cyclic voltammetry scanning, with a potential range of -0.5 to 0.5 V, a scan rate of 100 mV / s, and 10 cycles of scanning (the electrolyte was 0.01 M PBS, pH = 7.4, containing 5 mM dopamine and 20 mM ionic liquid), recorded as

[0052] ANME / AuNPs / SWNT~hemin~Aβ 1-42 / pDA+Ⅱ

[0053] 7) Elution of template molecules: Elution of the encapsulated amyloid peptide Aβ 1-42The template was eluted with 0.1 M (pH = 5.0) PBS containing 5% methanol for 120 minutes to obtain the surface molecular imprinting microsensor.

[0054] ANME / AuNPs / SWNT~hemin~Aβ@SMIP(ANME / / hemin / / SMIP)

[0055] Figure 2 To gradually modify the electrode in the presence of 5.0 mM [Fe(CN)6] 3- / 4- The cyclic voltammograms in 0.1M KCl solution and 0.1M KCl solution show that the acupuncture needle microelectrode (ANME) with weaker current intensity has an oxidation peak (0.4V) and almost no reduction peak, indicating that there is an irreversible electron transfer process in ANME, low conductivity and weak electrochemical activity. However, a pair of significant redox peaks appeared after electrodeposition, which is due to the excellent electrocatalytic activity of the atomic sites on gold nanoparticles (AuNPs) and the electrocatalytic activity of ANME, AuNPs and [Fe(CN)6] 3- / 4- The heterogeneous electron transfer between them is enhanced. After modification of single-walled carbon nanotubes, the peak current increases, which is attributed to the large specific surface area and fast mass transfer channel provided by carbon. The combination of the two can significantly improve the electron transfer efficiency and current response of the electrode surface. Self-assembled heme to [Fe(CN)6] 3- / 4- The external probe has good electrochemical activity, increased peak current, and can promote electron transfer in the matrix heterostructure. Therefore, heme is a potential probe suitable for providing electrochemical signals. 1-42 Afterwards, the peak current decreases, which is attributed to the central iron atom of heme binding to Aβ 1-42 The histidine residues in the β-catenin complex bind to the non-electroactive amyloid peptide Aβ through their imidazole groups. 1-42 The template molecules were fixed on the electrode surface, further hindering the electron transfer process. Subsequently, the peak current after electropolymerization of dopamine and ionic liquid decreased significantly, indicating that its electrochemical activity was low. The anodic and cathodic peaks were almost not observed, indicating that the electropolymerization of dopamine and ionic liquid produced a continuous and dense coating, which almost blocked the [Fe(CN)6] 3- / 4- The imprinting layer should play an anti-interference role and seal the electrochemical signal of the built-in heme. Finally, the template amyloid peptide Aβ is added in an acidic environment. 1-42 After elution, an amplified peak current appeared, [Fe(CN)6] 3- / 4- The signal further increased, which was attributed to the generation of molecularly imprinted cavities for electron transfer.

[0056] like Figure 3 , Figure 4As shown, the cyclic voltammogram and differential pulse voltammogram of the step-by-step modified electrode in PBS pH = 7 solution. Due to the electron transfer of the built-in heme, a pair of obvious redox peaks can be observed in the CV curve of ANME / / hemin. It is known that during the electropolymerization process of dopamine and ionic liquids, the small size and self-repulsion between molecules enable them to tightly cover the needle surface and wrap the amyloid peptide Aβ 1-42 template and hindered the electrical signal transmission of the embedded heme. Therefore, the peak current of the embedded heme was significantly reduced, and the Aβ 1-42 After template removal, the peak current of the built-in heme increased again. This may be due to the existence of the imprinted nanocavity forming an effective current transmission channel. However, when the sensor was incubated with amyloid peptide Aβ 1-42 After the solution, the peak current of the built-in heme decreased again, because the amyloid peptide Aβ was successfully captured in the structurally complementary nanocavity. 1-42 Template molecules, thereby blocking the current transmission channel. This further proves that the built-in signal probe can be used to detect amyloid peptide Aβ 1-42 The successful preparation of micro electrochemical sensor.

[0057] Application Example 1

[0058] The prepared micro electrochemical sensor was tested in the presence of different concentrations of amyloid peptide Aβ 1-42 (30fM~50000nM) solution for 30 minutes. Figure 5 As shown, with the increase of amyloid peptide Aβ 1-42 As the concentration increases, the peak current of the built-in heme gradually decreases. This current decrease is due to the fact that the imprinted nanocavity is filled with the structurally complementary amyloid peptide Aβ. 1-42 The molecules occupy the heme, thereby hindering the electron transfer of the built-in heme.

[0059] The prepared micro electrochemical sensor for amyloid peptide Aβ 1-42 During the detection, ΔI(I1-I2) (I1: peak current of ANME / / hemin / / SMIP; I2: ANME / / hemin / / SMIP binds to Aβ again) 1-42 The peak current after Aβ 1-42 There is a strong linear relationship between the logarithmic values ​​of concentration, such as Figure 6 As shown, the linear equation is ΔI(μA)=2.018lgC+31.13(R 2 =0.998). The linear range is 30fM~50000nM, and the detection limit is 0.05fM. The above results prove that the micro electrochemical sensor can be successfully applied to amyloid peptide Aβ 1-42 Sensitive detection of 40μM Aβ 1-42and Aβ 1-40 , osteopontin (OPN), nucleocapsid protein (SARS-CoV-2N protein, NP), mesothelin (MSLN), vascular endothelial growth factor (VEGF), bovine serum albumin (BSA), Na + Mg 2+ , Cl - , uric acid (UA) and dopamine (DA)) to study the specificity of microelectrochemical sensors, such as Figure 7 As shown in Figure 2, the signal changes of the microsensor before and after incubation were smaller than those in Aβ 1-42 The signal changes in the presence of , which indicates that the sensor has good specificity.

[0060] Comparative Example 1

[0061] In order to further prove the successful preparation of the micro electrochemical sensor, a non-micro electrochemical sensor was prepared without Aβ 1-42 The other operations were the same as those in Example 1. Figure 8 As shown, before and after elution and rebinding of Aβ 1-42 back,

[0062] The peak current of heme changes little before and after the template is removed. This is because there is no imprinted nanocavity in ANME / / hemin / / SNIP, which cannot provide specific recognition and binding sites, resulting in the amyloid peptide Aβ 1-42 It is impossible to bind to the electrode surface. The successful preparation of the micro-electrochemical sensor is further proved by comparing the micro-electrochemical sensor with the non-micro-electrochemical sensor.

[0063] Comparative Example 2

[0064] To further demonstrate the successful preparation of the micro-electrochemical sensor, ANME / AuNPs / SWNT~hemin and ANME / AuNPs~hemin were also prepared. The operation steps were the same as steps (1) to (4) of Example 1, except that ANME / AuNPs~hemin did not have step (3).

[0065] from Fig. 9 (CV graph) and Fig.10(DPV image) It can be seen that the electrode modified with single-walled carbon nanotubes is more responsive to the electrical signal of hemoglobin. The binding between single-walled carbon nanotubes (SWNTs) and hemoglobin (hemin) usually forms a complex through interaction and coordination. Hemoglobin molecules contain iron ions, which can interact with the surface or certain functional groups of carbon nanotubes to form a stable complex. Single-walled carbon nanotubes have a high surface area and good conductivity, which can effectively enhance the electrocatalytic activity of hemoglobin. Through surface modification, SWNTs can provide sites for coordination with hemoglobin and promote the transfer of electrons, thereby improving its performance in electrochemical sensors. If gold is directly combined with hemin, the possibility of binding is relatively small, and it cannot provide more binding area.

Claims

1. A method for detecting amyloid peptide Aβ 1-42 The method for preparing a micro electrochemical sensor is characterized in that: The steps include: 1) Pretreatment of acupuncture needles: grinding and polishing the acupuncture needles, ultrasonic cleaning, and drying the acupuncture needles for standby use; 2) Modification of gold nanoparticles: The acupuncture needle pretreated in step 1) is used as a working electrode, and the tip of the acupuncture needle is immersed in a HAuCl4 solution containing KCl, and a cyclic voltammetry scan is performed. The obtained electrode is recorded as ANME / AuNPs; 3) Modification of single-walled carbon nanotubes: The ANME / AuNPs electrode obtained in step 2) is used as a working electrode and electropolymerized in an aqueous solution containing 3,4-ethylenedioxythiophene and single-walled carbon nanotubes. After the polymerization is completed, the modified electrode is thoroughly washed with water and dried. The prepared electrode is marked as ANME / AuNPs / SWNT. 4) Heme modification: the ANME / AuNPs / SWNT electrode prepared in step 3) is immersed in a heme solution and incubated at 4°C to 25°C to obtain an electrode labeled as ANME / AuNPs / SWNT~hemin; 5) Binding of template molecules: The electrode prepared in step 4) is immersed in Aβ 1-42 Solution, incubated at 25°C to 37°C; 6) Modification of the imprinted polymer membrane: using the electrode treated in step 5) as the working electrode, electropolymerizing dopamine and the ionic liquid by cyclic voltammetry scanning; 7) Elution of template molecules: The encapsulated amyloid peptide Aβ treated in step 6) is washed with water. 1-42 The template is eluted to obtain the surface molecular imprinted microsensor ANME / AuNPs / SWNT~hemin~Aβ@SMIP.

2. A method for detecting amyloid peptide Aβ according to claim 1 1-42 The method for preparing a micro electrochemical sensor is characterized in that: The specific operation process of step 1) is: grinding and polishing the acupuncture needles, ultrasonically cleaning them in ethanol and deionized water respectively, and then drying the acupuncture needles with nitrogen for use.

3. A method for detecting amyloid peptide Aβ according to claim 1 1-42 The method for preparing a micro electrochemical sensor is characterized in that: In step 2), the scanning rate of the cyclic voltammetry scan is 25-100 mV / s, the potential range is alternating between -1.5 V and 0.5 V, and the scan is performed for 5-10 cycles. The concentration of the HAuCl4 solution is 2.5 mmol / L, and the 5-10 mm needle tip portion is immersed in the HAuCl4 solution containing KCl.

4. A method for detecting amyloid peptide Aβ according to claim 1 1-42 The method for preparing a micro electrochemical sensor is characterized in that: In step 3), the potential of the polymerization process is set to 1-1.2 V, the polymerization time is 100-200 seconds, the concentration of the 3,4-ethylenedioxythiophene solution is 0.01-0.02 mol / L, and the concentration of the single-walled carbon nanotube solution is 0.3-0.5 mol / L.

5. A method for detecting amyloid peptide Aβ according to claim 1 1-42 The method for preparing a micro electrochemical sensor is characterized in that: The solvent of the heme solution in step 4) is sodium hydroxide, the concentration is 3 to 5 mM, and the incubation time is 6 to 12 hours.

6. A method for detecting amyloid peptide Aβ according to claim 1 1-42 The method for preparing a micro electrochemical sensor is characterized in that: Step 5) Aβ 1-42 Solution is Aβ 1-42 Aβ was dissolved in 0.1 M PBS. 1-42 The solution concentration is 10-40 μM, and the incubation time is 30-60 min.

7. A method for detecting amyloid peptide Aβ according to claim 1 1-42 The method for preparing a micro electrochemical sensor is characterized in that: In step 6), the potential range of electropolymerization is -0.5 to 0.5 V, the scanning rate is 50 to 100 mV / s, the cycle scan is 10 to 20 times, the electrolyte is 0.01 M PBS, pH = 7.4, containing 5 to 8 mM dopamine and 20 to 25 mM ionic liquid.

8. A method for detecting amyloid peptide Aβ according to claim 1 1-42 The method for preparing a micro electrochemical sensor is characterized in that: The elution process of step 7) is to remove the encapsulated amyloid peptide Aβ 1-42 The template was eluted with a PBS solution containing methanol for 60 to 120 minutes, with the volume ratio of methanol to PBS being 1:

20.

9. A method for detecting amyloid peptide Aβ prepared by the preparation method according to any one of claims 1 to 8 1-42 Micro electrochemical sensor.

10. A method for detecting amyloid peptide Aβ as claimed in claim 9 1-42 Application of micro electrochemical sensors.

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