Preparation method and application of CuO2 / Au@CuS probe

Abstract

The present invention relates to the field of surface enhanced Raman scattering technology and photocatalysis technology, and in particular to a CuO 2 / Au@CuS probe preparation method and application thereof, the present invention prepares CuO 2 / Au@CuS, which can quickly, effectively and sensitively determine GSH in cells and serum; using CuS to wrap Au NPs can not only effectively solve the aggregation of Au NPs, but also enhance the Raman signal intensity through chemical mechanisms; at the same time, TMB is activated by H through the activity of CuS peroxidase nanozymes. 2 O 2 Oxidized to oxTMB with a special Raman signal, GSH then reduces oxTMB to TMB. GSH can be detected by this indirect method, and GSH is ‑2 ‑10 ‑8 Linear fitting in the mM range, detection limit (LOD) reached 9.94*10 ‑10 mM.

Description

Technical Field

[0001] The present invention relates to the field of surface enhanced Raman scattering technology and photocatalysis technology, and in particular to a CuO 2 Preparation method and application of / Au@CuS probe. Background Art

[0002] Glutathione (GSH) is a tripeptide compound composed of glutamic acid, cysteine, and glycine. The sulfhydryl group in the cysteine ​​residue makes it an important biologically active substance. GSH is widely present in animal and plant cells and is the most abundant non-protein sulfhydryl compound in cells. The content of GSH in various tissues and cells of the human body and its relationship with various diseases have attracted much attention and have been a hot topic of extensive research.

[0003] GSH participates in many biochemical reactions in the body and has very important physiological effects, such as the transport of amino acids, the synthesis of proteins and nucleic acids, and anti-oxidation. As an important antioxidant widely present in the body, GSH plays an important role in protecting the body from free radical damage, anti-tumor and anti-aging. In particular, the anti-mutation effect of GSH is beneficial to inhibit the mutation of cancer-inducing genes, and has a certain inhibitory effect on various cancer cell lesions such as liver cancer, lung cancer, skin cancer, and prostate cancer. It is said that GSH is the most effective anti-cancer substance in the human body. Changes in the concentration of GSH and related sulfhydryls in cells and tissues in the body are associated with a variety of major diseases. Therefore, the content of GSH is an important indicator for measuring the antioxidant capacity of the body.

[0004] It is reported that if the content of GSH in the body is lower than the normal level, it will lead to a series of diseases such as diabetes, alcoholic liver poisoning, cataracts, cancer, Parkinson's syndrome, cardiovascular disease, Alzheimer's disease (Alzheimer, senile dementia) and so on. Therefore, conventional diagnosis uses the concentration detection of GSH and related thiol compounds as an important basis for the diagnosis of certain diseases. It can be seen that the establishment of an efficient, sensitive and economical detection method for GSH and related thiol compounds is not only helpful for the clinical diagnosis and treatment of major diseases, but also has important significance for the research and application in many fields such as biology, medicine, life sciences, food, and medicine.

[0005] At present, a variety of detection technologies for measuring GSH have been developed, including chemical and instrumental methods, such as UV / visible spectrophotometry, fluorescence, enzyme cycling, electrochemical method, chemiluminescence, electrochemiluminescence, high performance liquid chromatography, gas chromatography, capillary electrophoresis, etc. Each method has its own advantages and disadvantages in terms of sensitivity, selectivity, stability, detection time, cost, instrumentation, etc. At present, there is no rapid, stable, specific, sensitive and economical determination method. This affects the application of GSH in high-throughput routine clinical testing and biological research.

[0006] According to the development trend of GSH detection technology, a method with high detection sensitivity is urgently needed to meet the requirements of high sensitivity and high specificity for the detection of trace GSH samples. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention aims to provide a CuO 2 / Au@CuS probe preparation method and application thereof, the present invention prepares CuO 2 / Au@CuS, rapid, effective and sensitive determination of GSH in cells and serum; TMB was activated by H 2 O 2 Oxidized to oxTMB with a special Raman signal, GSH then reduces oxTMB to TMB. GSH can be detected in this indirect way, and GSH is -2 -10 -8 Linear fitting in the mM range, detection limit (LOD) reached 9.94*10 -10 mM.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A CuO 2 The preparation method of the Au@CuS probe comprises the following steps:

[0010] S1. Synthesis of Au NPs:

[0011] S101. Add 5-10 parts by mass of HAuCl 4 ·3H 2 Heat O and 80-100 parts of deionized water to boiling and then quickly add C 6 H 5 Na 3 O 7 , boil the solution for 20-30 minutes and then let it cool to room temperature to obtain seed solution;

[0012] S102. Take 50-60 parts of seed solution by mass, heat it to 90-100°C, add 1-2 parts of HAuCl 4 ·3H 2 O was reacted for 30-40 min, and this step was repeated three times to obtain Au NPs;

[0013] S2. Synthesis of Au@CuS:

[0014] S201. Add 0.1-0.3 parts of CuCl by mass 2 , 60-70 parts of PVP and 5-10 parts of Au NPs were added to deionized water and stirred for 5-10 minutes, and then 20-30 parts of NaOH were added to adjust the pH value to 9-10, and stirred for 2-3 minutes;

[0015] S202. 0.003-0.004 parts by mass of N 2 H 4 ·H 2 O was added to the above solution, stirred for 2-3 minutes, and 0.2-0.3 parts of Na 2 S, stir the solution in a water bath at 70-80°C for 2-3h, wash twice with deionized water, and disperse in 10-20 parts of deionized water;

[0016] S3.CuO 2 Synthesis of Au@CuS:

[0017] S301. Take 5-10 parts of Au@CuS, 2-3 parts of PVP, and 0.03-0.04 parts of CuCl by mass. 2 Disperse in 20-30 parts of deionized water, stir for 6-8 hours, then add 20-30 parts of NaOH to adjust the pH value to 9-10, and stir for 10-20 minutes;

[0018] S302. Add 0.2-0.3 parts of H by mass to the solution treated in step S301. 2 O 2 , stirred overnight in an ice region to obtain the CuO 2 / Au@CuS.

[0019] Preferably, in steps S101 and S102, the HAuCl 4 ·3H 2 The concentration of O is 20-25 mM.

[0020] Preferably, in step S101, the C 6 H 5 Na 3 O 7 The weight volume percentage is 1-2%.

[0021] Preferably, in steps S201 and S301, the CuCl 2 The concentration is 0.5-1mM.

[0022] Preferably, in step S202, the Na 2 The concentration of S is 320-340 mg / mL.

[0023] A CuO prepared according to the preparation method 2 Application of Au@CuS probe in the detection of GSH.

[0024] Preferably, the method comprises the following steps:

[0025] Take 0.5-1 part of CuO by mass 2 / Au@CuS was mixed with PBS buffer with a pH range of 5-9 in equal proportions and allowed to stand for 10-20 min. Then 0.02-0.03 parts of 10 -2 -10 -6 M TMB with a concentration of 0.08-0.1 parts per 10 -2 -10 -8 mM GSH was measured by a quartz capillary after the sample was drawn up and measured under a 785 nm wavelength laser through a 50× objective lens, with a collection time of 10 s and an integration of 50 times.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. Prepare CuO 2 / Au@CuS, rapid, efficient and sensitive determination of GSH in cells and serum;

[0028] 2. Wrapping Au NPs with CuS not only effectively solves the aggregation of Au NPs, but also enhances the Raman signal intensity through chemical mechanisms;

[0029] 3.TMB is activated by H through the peroxidase activity of CuS 2 O 2 Oxidized to oxTMB with a special Raman signal, GSH then reduces oxTMB to TMB. GSH can be detected in this indirect way, and GSH is -2 -10 -8 Linear fitting in the mM range, detection limit (LOD) reached 9.94*10 -10 mM. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The CuO of the present invention 2 / Au@CuS probe preparation process and detection mechanism diagram, where: (A) CuO 2 / Au@CuS probe preparation process flow chart; (B)CuO 2 Mechanism diagram of GSH detection by Au@CuS probe; (C) SERS detection flow chart;

[0031] Figure 2 The CuO of the present invention 2 / Au@CuS probe characterization diagram, where: (A) Au@CuS and CuO 2 SEM image of / Au@CuS (scale: 10nm); (B)CuO 2 TEM image of / Au@CuS (scale: 20nm); (C)CuO 2 HAADF-STEM image of / Au@CuS and elemental mapping of Au, Cu, and S (scale: 20 nm); (D)CuO 2 XRD patterns of Au@CuS / Au@CuS; (E)TMB, CuO 2 / Au@CuS+PBS、CuO 2 / Au@CuS+TMB,CuO 2 UV-visible absorption spectrum of / Au@CuS+TMB+PBS;

[0032] Figure 3 The Au@CuS and CuO of the present invention 2 / Au@CuS probe peroxidase activity detection diagram, where: (A) Au@CuS+TMB+H 2 O 2( (B) The corresponding double reciprocal graph of the catalytic activity of Au@CuS; (C) CuO 2 / Au@CuS+TMB+PBS (pH=5) UV-visible absorption spectrum intensity change over time; (D) Linear fitting graph of UV intensity at 650nm over time;

[0033] Figure 4 The CuO of the present invention 2 SERS performance of Au@CuS probe and SERS detection of GSH, where: (A) different concentrations of TMB (10 -2 ,10 -3 ,10 -4 ,10 -5 ,10 -6 M) mixed solution with CuO 2SERS spectra of the mixed solution of / Au@CuS+PBS (pH=5); (B) SERS spectra of CAC treated with different concentrations of PBS (pH=5, 6, 7, 8, 9) and 10 -2 SERS spectra of TMB reaction of M; (C) CuO 2 / Au@CuS+TMB+PBS(pH=5)+GSH(10 -2 mM) within 20min, 1611cm -1 Intensity change diagram per minute; (DF) 5mLCuO 2 / Au@CuS, mixed with PBS buffer at pH = 5 in equal proportions, and then 20 μL 10 -2 M of TMB, and then after standing for 5 min, different concentrations of GSH (10 -2 -10 -8 mM), characteristic peak and linear fitting diagram obtained by capillary absorption test;

[0034] Figure 5 The CuO of the present invention 2 / Au@CuS probe reproducibility, selectivity, and stability test diagram, where: (AB) reproducibility, the system is CuO 2 / Au@CuS+TMB+PBS (pH=5) tested 20 groups of oxTMB SERS images and 1611cm -1 Characteristic peak intensity diagram; (CD) SERS images at 1, 5, 10, 15, 20, 25, and 30 days of testing and 1611 cm -1 Characteristic peak intensity plot. DETAILED DESCRIPTION

[0035] The present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Experimental materials of the present invention:

[0037] Glutathione (GSH), copper chloride (CuCl 2 2H2O), sodium sulfide (Na 2 S), sodium hydroxide (NaOH), polyvinyl pyrrolidone (PVP-K30), tetramethylbenzidine (TMB), lysine (Lys), histidine (His), glutamine (Glu), proline (Pro), methionine (Met), cysteine ​​(Cys), glycine (Gly), sodium dihydrogen phosphate (Na 2HPO 4 ), citric acid (C 6 H 5 Na 3 O 7 ), Rhodamine 6G (R6G) was purchased from Aladdin (Shanghai, China).

[0038] Chloroauric acid trihydrate (HAuCl 4 ·3H 2 O) was purchased from Maclean.

[0039] Hydrogen peroxide 30% (H 2 O 2 ), hydrazine monohydrate (N 2 H 4 ·H 2 O) was purchased from Xilong Science.

[0040] The reduced glutathione content detection kit was purchased from Solebol.

[0041] Ultrapure water (≥18.2 MΩcm, 25 °C) was used in all experimental parts.

[0042] The experimental apparatus of the present invention:

[0043] Nanoparticle size analyzer (Zetasizer Nano ZS; Malvern, UK), ultraviolet visible spectrophotometer (UV) (UV2600; SHI MADZU, Japan), inductively coupled plasma mass spectrometer (ICP-MS) (NexION300X; PerkinElmer, USA), X-ray diffraction (XRD) (Bruker-D8 Advance; Bruker, Germany), transmission electron microscope (TEM) (Talos F200S; Thermo Fisher Scientific, USA), scanning electron microscope (SEM) (QuantaFEG 450; FEI Company, USA), laser confocal microscope Raman spectrometer (In Via; Renishaw, UK).

[0044] See also Figure 1-5 , the present invention provides a technical solution:

[0045] Example 1

[0046] A CuO 2 Preparation method of Au@CuS probe:

[0047] (1) Synthesis of Au NPs

[0048] First, prepare the seed solution and take 5 mL of 20 mM HAuCl 4 ·3H 2 O and 100 mL of deionized water were heated to boiling and then C 6 H 5 Na 3 O 7 (1% (w / v)), boil the solution for 20 min and then let it cool to room temperature. Take 50 mL of seed solution, heat it to 90°C, add 1 mL of HAuCl 4 ·3H 2 O was reacted for 30 min, and this step was repeated three times to obtain Au NPs.

[0049] (2) Synthesis of Au@CuS

[0050] 100 μL 0.5 mM CuCl 2 , 64 g PVP and 5 mL Au NPs were added to 20 mL deionized water and stirred for 5 min. Then 25 mL NaOH (pH = 9) was added and stirred for 2 min. 3.2 μL N 2 H 4 ·H 2 O was added to the above solution, stirred for 2 min, and 200 μL Na 2 S (320 mg / mL), the solution was stirred in a water bath at 70°C for 2 h, washed twice with deionized water, and dispersed in 10 mL of deionized water.

[0051] (3)CuO 2 Synthesis of Au@CuS

[0052] Take 5mL Au@CuS, 2g PVP, 34.1mg CuCl 2 Disperse in 20 mL of deionized water, stir for 6 h, add 25 mL of NaOH (pH = 9) and stir for 10 min. Then add 200 μL of H 2 O 2 , stirred overnight in an ice field. 2 After washing, / Au@CuS was redissolved in 5 mL of deionized water and stored in a refrigerator at 4 °C until use.

[0053] This embodiment also provides a CuO 2 The application of / Au@CuS in GSH detection includes the following steps:

[0054] Take 0.5mLCuO 2 / Au@CuS was mixed with PBS buffer at pH = 5 in equal proportions and allowed to stand for 10 min. Then 20 μL 10 -2M TMB and 80 μL of different concentrations of GSH (10 -2 -10 -8 mM). After the sample was sucked with a quartz capillary, it was measured through a 50× objective lens under a 785nm wavelength laser, with a collection time of 10s and an integration of 50 times.

[0055] Performance Testing

[0056] 1.CuO 2 Structural characterization of / Au@CuS

[0057] The prepared CuO 2 / Au@CuS was structurally characterized. The results are as follows Figure 2 As shown, through Figure 2 The SEM of A shows that the surface of Au@CuS is relatively smooth. 2 / Au@CuS, it can be seen that there are many nanospheres attached to the surface. At the same time, the transmission image shows that CuO 2 The average size of / Au@CuS is about 60nm( Figure 2 B), and the surface is covered with a layer of PVP. PVP acts as a stabilizer during the synthesis process and can control the synthesis of CuO 2 The morphology of the SERS probe can effectively enrich GSH during the detection process and improve the biocompatibility of the SERS probe. Figure 2 In C, the distribution of various elements can be observed, among which the distribution area of ​​S element is smaller than that of Cu element. It can be seen that CuO is successfully wrapped outside CuS. 2 .exist Figure 2 CuO is shown in D 2 The XRD spectrum of / Au@CuS is consistent with the corresponding characteristic peaks, proving that CuO 2 / Au@CuS was successfully prepared.

[0058] like Figure 2 E shows TMB, CuO 2 / Au@CuS+PBS、CuO 2 / Au@CuS+TMB,CuO 2 UV-visible absorption spectrum of / Au@CuS+TMB+PBS(pH=5). 2 After the Au@CuS was treated with PBS buffer at pH = 5 for 5 min, TMB was added, and TMB was oxidized to generate oxTMB. The UV spectrum of oxTMB has characteristic peaks at 370nm, 450nm, and 652nm. 2 / Au@CuS+TMB, the UV absorbance did not change. This phenomenon indicates that CuO2 / Au@CuS can generate H under acidic conditions 2 O 2 , then expose the CuO 2 Au@CuS / Au@CuS inside. Under the catalysis of Au@CuS with peroxidase activity, H 2 O 2 TMB is oxidized to oxTMB, which also proves that CuO 2 It successfully attached to the surface of Au@CuS. When GSH was added, GSH reduced oxTMB to colorless TMB, and this reduction process was irreversible. Because of this phenomenon, it is expected that CuO 2 / Au@CuS biosensor can be constructed for sensitive detection of GSH.

[0059] 2. Peroxidase activity and kinetics of Au@CuS

[0060] 500 μL of different concentrations of HO 2 O 2 (0, 1, 2, 5, 10 mM) was mixed with 250 μL Au@CuS and 250 μL 10 mM TMB and incubated at room temperature for 2 min to detect the addition of different concentrations of H 2 O 2 AC peroxidase activity at 654 nm. Record the absorbance of each sample at 654 nm. At the same time, record the absorbance of each sample at 654 nm. 2 O 2 The UV-visible absorption spectrum of the sample was changed every 1 minute, and the linear fitting graph was drawn through the UV absorption intensity at 654 nm. The results are shown in Figure 3 As shown:

[0061] Figure 3 A shows that as H 2 O 2 As the concentration increases, the UV absorption intensity of the system becomes stronger. This is because H 2 O 2 The more, the more oxygen free radicals are released, and a large number of oxygen free radicals oxidize more TMB to oxTMB, so the characteristic peak UV absorption intensity is enhanced. Figure 3 B shows that the oxidation rate of TMB is related to the concentration of H 2 O 2 There is a good linear relationship between (0-20mM), y=7.51x+4.67, R 2 =0.99. Figure 3C, 3D shows the changes in the UV-visible absorption spectrum of the system at different times, and records the UV absorption intensity at 652nm. As the incubation time of the system increases, its UV absorption intensity becomes stronger and stronger, and the change in absorption intensity is linearly correlated in the range of 0 to 14 minutes. At this time, y = 0.20x + 0.02, R 2 =0.9.

[0062] 3.CuO 2 SERS performance optimization of Au@CuS and SERS detection of GSH

[0063] Optimize each condition in the performance test experiment. Figure 4 As shown in A, the concentration of TMB (10 -2 -10 -6 M) increased, oxTMB at 1611cm -1 The intensity of the Raman characteristic peak at the position gradually increases, so the concentration of 10 -2 The effect of pH value on the intensity of SERS characteristic peak was verified by adding PBS buffer with different pH values ​​(pH=5, 6, 7, 8, 9). Figure 4 B shows that at pH = 5, the Raman characteristic peak signal intensity is the largest, and as the pH increases, the characteristic peak intensity decreases. At the same time, in other studies, CuO 2 At pH = 5.5, it can begin to decompose into Cu 2+ and H 2 O 2 Therefore, the pH of the subsequent experiments was set to 5, under which the CuO 2 All of them were decomposed, and the peroxidase activity of Au@CuS reached the highest. Figure 4 C represents the 1611cm at different times (0-20min) after adding GSH -1 From the intensity change of the characteristic peak at 0-4 min, it can be seen that the characteristic peak intensity decreased significantly within 0-4 min and reached a plateau after 4 min. This proves that oxTMB reacted with most of the GSH within 0-4 min. Therefore, in subsequent experiments, the optimal reaction conditions were: TMB concentration of 10 -2 M, buffer pH was 5.0, and incubation time was 5 min.

[0064] Detection of CuO 2 / Au@CuS SERS detection sensitivity of GSH, the results are as follows Figure 4 D: Add different concentrations of GSH (10 -2 -10 -8 mM), with the increase of GSH concentration, 1611cm -1The more obvious the decrease of the characteristic peak intensity is, the more obvious the decrease is. This proves that this indirect detection method of GSH is feasible. Figure 4 F shows that the change of characteristic peak intensity has good linearity within a certain GSH concentration range, at this time y = -0.91x + 1.72, R 2 =0.97, can detect 10 -8 mM GSH, the detection limit (LOD) has reached 9.94*10 -10 mM, which indicates that based on CuO 2 / Au@CuS SERS detection method has high sensitivity.

[0065] 4.CuO 2 Reproducibility, selectivity and stability testing of Au@CuS

[0066] In the system CuO 2 / Au@CuS+TMB+PBS (pH=5) to verify CuO 2 / Au@CuS as a Raman substrate reproducibility, such as Figure 5 A and 5B show that 20 groups of characteristic peak intensities were tested, and their RSD was 5.13%. 2 / Au@CuS as a substrate has good reproducibility for GSH detection. 2 / Au@CuS was stored in a refrigerator at 4°C for 1, 5, 10, 15, 20, 25, and 30 days, and the characteristic peak intensity of GSH was detected by comparison. Figure 5 In C and 5D, it can be seen that the characteristic peak intensity is stable within 30 days, with RSD = 13.93%. Since CuS is wrapped outside AuNPs, the aggregation of Au is suppressed, making CuO 2 / Au@CuS is stable over a long period of time and has good reproducibility.

[0067] Referring to the above content, the present invention successfully prepared CuO 2 / Au@CuS can quickly, effectively and sensitively measure GSH in cells and serum. Encapsulating Au NPs with CuS not only effectively solves the aggregation of Au NPs, but also enhances the Raman signal intensity through chemical mechanisms. At the same time, TMB is activated by H 2 O 2 Oxidized to oxTMB with a special Raman signal, GSH then reduces oxTMB to TMB. GSH can be detected by this indirect method, and GSH is -2 -10 -8 Linear fitting in the mM range, detection limit (LOD) reached 9.94*10 -10mM, which meets the requirements for high sensitivity and high specificity in the detection of trace GSH samples.

[0068] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a CuO2 / Au@CuS probe, characterized in that: The following steps are involved: S1. Synthesis of Au NPs: S101. Heat 5-10 parts of HAuCl4·3H2O and 80-100 parts of deionized water to boiling, then quickly add C6H5Na3O7, boil the solution for 20-30 min, and then let it cool to room temperature to obtain a seed solution; S102. Take 50-60 parts of the seed solution by mass and heat it to 90-100°C, add 1-2 parts of HAuCl4·3H2O and react for 30-40 minutes, and repeat this step three times to obtain Au NPs; S2. Synthesis of Au@CuS: S201. 0.1-0.3 parts of CuCl2, 60-70 parts of PVP and 5-10 parts of Au NPs were added to deionized water and stirred for 5-10 min, and then 20-30 parts of NaOH were added to adjust the pH value to 9-10, and stirred for 2 -3 min; S202. Add 0.003-0.004 parts of N2H4·H2O by mass to the above solution, stir for 2-3 min, add 0.2-0.3 parts of Na2S, stir the solution in a water bath at 70-80°C for 2-3 h, wash twice with deionized water, and disperse in 10-20 parts of deionized water; S3. Synthesis of CuO2 / Au@CuS: S301. Disperse 5-10 parts of Au@CuS, 2-3 parts of PVP, and 0.03-0.04 parts of CuCl2 in 20-30 parts of deionized water, stir for 6-8h, then add 20-30 parts of NaOH to adjust the pH to 9-10, and stir for 10-20 min; S302. Add 0.2-0.3 parts of H2O2 to the solution treated in step S301 by mass, and stir overnight in an ice field to obtain the CuO2 / Au@CuS; The application of the CuO2 / Au@CuS probe prepared by the preparation method in the detection of GSH specifically includes: Take 0.5-1 parts of CuO2 / Au@CuS by mass, mix it with PBS buffer with a pH range of 5-9 in equal proportions, let it stand for 10-20 minutes, and then add 0.02-0.03 parts of 10 -2 -10 -6 M TMB with a concentration of 0.08-0.1 parts per 10 -2 -10 -8 After the sample was drawn up with a quartz capillary, it was measured through a 50× objective lens under a 785 nm wavelength laser, with an acquisition time of 10 s and an integration of 50 times.

2. The method for preparing a CuO2 / Au@CuS probe according to claim 1, characterized in that: In steps S101 and S102, the concentration of HAuCl4·3H2O is 20-25 mM.

3. The method for preparing a CuO2 / Au@CuS probe according to claim 1, characterized in that: In step S101, the weight volume percentage of C6H5Na3O7 is 1-2%.

4. The method for preparing a CuO2 / Au@CuS probe according to claim 1, characterized in that: In steps S201 and S301, the concentration of CuCl2 is 0.5-1 mM.

5. The method for preparing a CuO2 / Au@CuS probe according to claim 1, characterized in that: In step S202, the concentration of Na2S is 320-340 mg / mL.

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