Electrochemical biological chiral sensor based on gold and silver nanostar composite material

Abstract

The invention discloses an electrochemical biological chiral sensor based on a gold and silver nanostar composite material. The electrochemical biological chiral sensor comprises an electrode substrate and the gold and silver nanostar composite material modified on the electrode substrate, the gold and silver nanostar composite material is a composite material with a gold nanostar material as a core and silver as a shell. The invention further discloses a preparation method of the electrochemical bio-chiral sensor and a method for identifying amino acid enantiomers by adopting the electrochemical bio-chiral sensor. After the electrochemical biological chiral sensor provided by the invention is incubated in different chiral amino acid solutions, the measured redox peak values are different, and by comparing the redox peak values of the to-be-detected amino acid solution and the same amino acid D-type and L-type enantiomers, the amino acid in the to-be-detected solution can be identified to be D-type, L-type or mixed type.

Description

Technical Field

[0001] The present invention belongs to the field of electrochemical technology, and in particular relates to an electrochemical biochiral sensor based on a gold@silver nanostar composite material. Background Art

[0002] Chirality is a common phenomenon in nature, with enantiomers of different configurations generally exhibiting distinct biological activities. Currently, chiral drugs are becoming increasingly important. In the asymmetric synthesis of chiral drugs, chiral amino acids are often used as chiral precursors and chiral catalyst ligands. Consequently, chiral recognition in amino acids has attracted considerable attention.

[0003] Over the past two decades, significant progress has been made in the research and application of fluorescent probes for the enantioselective recognition of chiral compounds. Fluorescent probes have potential applications in the rapid analysis of asymmetric reactions and the monitoring of chiral molecules in biological systems. However, chiral fluorescent probes are limited in number and require complex recognition conditions. Electrochemical chiral sensors, a new analytical method that combines chiral recognition research with electrochemical testing techniques, offer advantages such as high sensitivity, good selectivity, ease of operation, and amenability to miniaturization. Nanomaterials, with their excellent properties such as large surface area, strong adsorption capacity, and good biocompatibility, have been widely used in electroanalytical chemistry research. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides an electrochemical biochiral sensor based on a gold@silver nanostar composite material.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] On the one hand, the present invention provides an electrochemical biochiral sensor based on a gold@silver nanostar composite material, comprising an electrode substrate and a gold@silver nanostar composite material modified on the electrode substrate; the gold@silver nanostar composite material is a composite material with a gold nanostar material as a core and a silver shell.

[0007] In certain specific embodiments, the electrode substrate is selected from at least one of a glassy carbon electrode, a gold electrode, a graphite electrode, an indium tin oxide electrode, and an enzyme-modified electrode.

[0008] As a preferred embodiment, the preparation method of the gold@silver nanostar composite material comprises the following steps:

[0009] (1) chloroauric acid and trisodium citrate are heated in an aqueous solution and refluxed for 10 to 20 minutes to prepare gold nanoparticles (AuNPs);

[0010] (2) Gold nanoparticles and N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) sodium salt buffer (HEPES) are dispersed in water; chloroauric acid solution is added and stirred for 1 to 5 minutes; then hydroxylamine hydrochloride solution is added and stirred for 10 to 20 minutes; after centrifugation and concentration, the mixture is redispersed in N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) sodium salt buffer (HEPES) to obtain gold nanostar materials (AuNSs);

[0011] (3) After reacting ascorbic acid and the gold nanostar material in N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) sodium salt buffer for 1 to 5 minutes, a silver source is added and the reaction is continued for 3 to 7 minutes to obtain the gold@silver nanostar composite material.

[0012] As a preferred embodiment, in step (1), the molar ratio of the chloroauric acid solution to trisodium citrate is (1-100):(300-500).

[0013] And / or, in step (2), the molar ratio of the sodium salt of N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) to chloroauric acid and hydroxylamine hydrochloride is (1-100):(1-5):(1-5).

[0014] And / or, in step (2), the molar ratio of the gold nanoparticles to hydroxylamine hydrochloride is (1-5): (50-100).

[0015] And / or, in step (3), the molar ratio of ascorbic acid to silver in the silver source is (1-5):(1-5).

[0016] And / or, in step (3), the molar ratio of the gold nanostar material to Ag in the silver source is 1 to 11450000:1.

[0017] In another aspect, the present invention provides a method for preparing the electrochemical biochiral sensor based on the gold@silver nanostar composite material, comprising the following steps:

[0018] The dispersed droplets of the gold@silver nanostar composite material are applied on an electrode substrate, and the electrochemical biological chiral sensor is obtained after the dispersion medium evaporates.

[0019] As a preferred embodiment, the dispersion medium of the gold@silver nanostar composite material dispersion is N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) sodium salt buffer (HEPES).

[0020] As a preferred embodiment, in the dispersion of the gold@silver nanostar composite material, the concentration of Ag is 45 pM to 0.45 mM.

[0021] And / or, the concentration of the N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) sodium salt buffer solution is 5-15 mM.

[0022] In some specific embodiments, the electrode substrate is pre-treated by polishing, washing and drying.

[0023] In another aspect, the present invention provides use of the electrochemical biochiral sensor based on the gold@silver nanostar composite material in identifying amino acid enantiomers.

[0024] In another aspect, the present invention provides a method for identifying amino acid enantiomers, comprising the steps of:

[0025] The electrochemical biochiral sensor based on the gold@silver nanostar composite material is incubated in a test amino acid solution, and then the oxidation peak current of the test amino acid solution is measured using differential pulse voltammetry under the electrochemical window.

[0026] Preferably, the solvent of the amino acid solution to be tested is phosphate buffer.

[0027] Preferably, the concentration of the amino acid in the amino acid solution to be tested is 0.5-2 mM.

[0028] Preferably, the concentration of the phosphate buffer is 0.1-1 mol / L, and the pH is 6.0-8.0.

[0029] Preferably, the voltage of the electrochemical window is 0.4-1.2V.

[0030] In the technical solution of the present invention, the redox peaks measured by the electrochemical biochiral sensor after incubation in amino acid solutions of different chirality are different. By comparing the redox peaks of the amino acid solution to be tested with the D-type and L-type enantiomers of the same amino acid, it is possible to identify whether the amino acid in the test solution is D-type, L-type, or a mixed type.

[0031] In the technical solution of the present invention, the amino acid enantiomers are amino acid enantiomers having electrochemical signals, such as L-tryptophan (L-Trp) and D-tryptophan (D-Trp), L-tyrosine (L-Tyr) and D-tyrosine (D-Tyr), etc.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] This invention uses a gold@silver nanostar composite material to construct an electrochemical biochiral sensor capable of electrochemically recognizing chiral amino acids. Controlling the thickness of the silver shell in the gold@silver nanostar composite improves recognition efficiency; a thicker silver shell results in better chiral recognition. The gold@silver nanostar composite material provided by this invention offers the advantage of adjustable chiral recognition capabilities, allowing for tailored adjustments to the specific needs of the test subject. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 (A) Transmission electron microscopy image, (B) high-angle annular dark field image, (C) elemental distribution map of the Ag element by energy dispersive X-ray spectroscopy (EDS), (D) elemental distribution map of the Au element by EDS, (E) composite image of the EDS distribution maps of Ag and Au elements, and (F) EDS line scan image of the Au@10mM Ag NSs prepared in Example 1 of the present invention;

[0035] Figure 2 This is the XPS spectrum analysis of the AuNSs prepared in Example 1 of the present invention;

[0036] Figure 3 This is the XPS spectrum analysis of the Au@10mM Ag NSs prepared in Example 1 of the present invention;

[0037] Figure 4 This is the high-resolution XPS pattern of Ag 3d of Au@10mM Ag NSs prepared in Example 1 of the present invention;

[0038] Figure 5 This is a high-resolution XPS pattern of O1S of Au@10mM Ag NSs prepared in Example 1 of the present invention;

[0039] Figure 6 Zeta potential diagrams of (a) AuNSs, (b) Au@0.1mM Ag NSs, (c) Au@1mM AgNSs, and (d) Au@10mM Ag NSs prepared in Example 1 of the present invention;

[0040] Figure 7 Dynamic light scattering patterns of (a) AuNSs, (b) Au@0.1mM Ag NSs, (c) Au@1mM AgNSs, and (d) Au@10mM Ag NSs prepared in Example 1 of the present invention;

[0041] Figure 8Cyclic voltammograms of bare GCE, AuNSs / GCE, Au@0.1mM Ag NSs / GCE, Au@1mM AgNSs / GCE, and Au@10mM Ag NSs / GCE in Example 2 of the present invention;

[0042] Figure 9 Electrochemical impedance spectroscopy (EIS) graphs of bare GCE, AuNSs / GCE, Au@0.1 mM Ag NSs / GCE, Au@1 mM AgNSs / GCE, and Au@10 mM Ag NSs / GCE in Example 2 of the present invention;

[0043] Figure 10 The oxidation peak current ratio I of Trp enantiomers in Example 1 of the present invention is L / I D Functional relationship diagram of the Ag concentration in the Au@Ag NSs dispersion;

[0044] Figure 11 is the oxidation peak current ratio I of Trp enantiomers measured by the electrochemical biosensor constructed in Comparative Example 1 of the present invention L / I D .

[0045] Figure 12 This is a transmission electron microscopy image of the AuNSs prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0046] The following embodiments are merely some of the embodiments of the present invention, rather than all of them. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by those skilled in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0047] In the present invention, unless otherwise specified, all equipment and raw materials can be purchased from the market or are commonly used in the industry. The methods in the following embodiments, unless otherwise specified, are all conventional methods in the art.

[0048] Example 1:

[0049] This example synthesizes a gold@silver nanostar composite material, and the preparation process is as follows:

[0050] (1) Synthesis of gold nanomaterials (AuNPs):

[0051] 100 mL of 1 mM chloroauric acid solution was added to a 250 mL round-bottom flask and heated to reflux under continuous stirring. 10 mL of 38.8 mM trisodium citrate solution was added, and the solution was observed to gradually turn dark red. After heating and reflux for 15 minutes, the solution was stopped and cooled with stirring for 15 minutes. The resulting AuNPs dispersion (AuNPs concentration of 0.91 mM) was stored in a refrigerator at 4°C.

[0052] (2) Synthesis of gold nanostar materials (AuNSs):

[0053] In a 100-mL beaker, 750 μL of the synthesized AuNPs dispersion, 100 mM (18.75 mL) of N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) sodium salt buffer (HEPES), and 38.5 mL of water were added sequentially. Under stirring, 1 mM (22.5 mL) of chloroauric acid solution was added dropwise. After reacting for 2 minutes, 40 mM (750 μL) of hydroxylamine hydrochloride solution was added and the reaction was stopped after stirring for 15 minutes. The resulting solution was centrifuged at 4500 rpm for 12 minutes, concentrated to half of the initial volume, and redispersed in 40.625 mL of 12 mM HEPES solution to obtain an AuNSs dispersion (AuNSs concentration was 0.571 mM), which was then stored in a refrigerator at 4°C.

[0054] (3) Synthesis of gold@silver nanostar composites (Au@Ag NSs):

[0055] Add 3 mL of AuNSs dispersion to a pre-washed 5 mL glass bottle; add 10 mM 150 μL ascorbic acid (L-AA) solution under continuous stirring, mix evenly and react for 2 minutes; slowly add 150 μL of 10 mM AgNO3 solution, continue stirring for 5 minutes and then stop the reaction; after the reaction, centrifuge the resulting solution at 4500 rpm for 3 minutes to obtain core-shell structured Au@Ag NSs, which is dispersed in 3.3 mL of 12 mM HEPES buffer to obtain Au@Ag NSs dispersion, and store in a refrigerator at 4°C.

[0056] In step (3) of this embodiment, AgNO 3 solutions with other concentrations were also used to prepare gold@silver nanostar composite materials, with a concentration of 1 nM to 1 mM.

[0057] Figure 12 The figure shows a transmission electron microscope image of the gold nanostar material synthesized in step (2). It can be seen from the figure that the gold nanostar material was successfully prepared in this embodiment.

[0058] Figure 1The figure shows the experimental characterization of the gold@silver nanostar composite material (Au@10mM Ag NSs) prepared from 10mM AgNO3 solution: Figure 1 A and 1B are the transmission electron microscopy image and high-angle annular dark field image of Au@10mM Ag NSs, respectively. Figure 1 C and Figure 1 D is the element distribution map of Ag and Au elements at corresponding positions obtained by element mapping analysis, proving that Ag and Au elements coexist in the composite material. At the same time, from the composite map of Ag and Au element distribution map ( Figure 1 E) shows that the distribution profile of Ag element is larger than that of Au element, which successfully proves that the material is a core-shell structured gold-silver nanoalloy. In addition, the EDS line scan analysis of Au@10mM Ag NSs ( Figure 1 F), further verifying that the material is a core-shell structure of gold core and silver shell.

[0059] Figure 2 and 3 The XPS full spectrum analysis of AuNSs and Au@Ag 10mM NSs synthesized in this example is shown. Compared with AuNSs, the full spectrum of Au@Ag NSs shows obvious Ag 3d characteristic peaks, which fully proves that silver has been successfully introduced into the Au@Ag NSs material. Figure 4 As shown in the figure, after fitting the characteristic peaks of Ag 3d, two peaks at 367.8eV and 373.8eV were found to be related to Ag. 0 The corresponding characteristic peaks indicate the successful growth of the silver shell on the surface of Au@Ag NSs. At the same time, the peaks corresponding to the oxidized Ag were also observed in the high-resolution XPS spectrum of Ag 3d. + The characteristic peaks (368.1eV and 374.1eV) of Ag further confirm the existence of oxidized Ag. In addition, the high-resolution XPS spectrum of O 1s ( Figure 5 ), a characteristic peak corresponding to the Ag–O bond appeared at 532.7 eV, proving that the oxidation product of L-AA, L-dehydroascorbic acid (L-DHA), was bound to the Ag shell through the Ag–O bond.

[0060] Figure 6Shown are the zeta potential plots of (a) AuNSs synthesized in this example, (b) a gold@silver nanostar composite material (Au@0.1mM Ag NSs) prepared from a 0.1mM AgNO3 solution, (c) a gold@silver nanostar composite material (Au@1mM Ag NSs) prepared from a 1mM AgNO3 solution, and (d) Au@10mM Ag NSs. Because the AuNSs were stored in HEPES buffer, the isoelectric point of HEPES is pH 5.0, and the overall pH of the composite solution is 7.0, the AuNSs exhibit negative charge, with a zeta potential of -18.8mV. As the AgNO3 concentration gradually increases, the electronegativity of the composite material significantly increases (from -18.8mV to -24.1mV), fully demonstrating the successful preparation of the Au@Ag NSs composite material in this example.

[0061] Figure 7 Shown are dynamic light scattering patterns of (a) AuNSs, (b) Au@0.1mM Ag NSs, (c) Au@1mM Ag NSs, and (d) Au@10mM Ag NSs synthesized in this example. The average particle sizes of the AuNSs, Au@0.1mM Ag NSs, Au@1mM Ag NSs, and Au@10mM Ag NSs are 73.2nm, 80.7nm, 98.1nm, and 104.9nm, respectively. The figures also show that the thickness of the silver shell on the composite surface increases with increasing AgNO3 concentration.

[0062] Example 2:

[0063] This embodiment provides an electrochemical biochiral sensor based on a gold@silver nanostar composite material, and the preparation method is as follows:

[0064] The glassy carbon electrode (GCE, electrode core diameter 3 mm) was polished with alumina powder with a particle size of 0.05 μm, rinsed with ultrapure water, and dried under an infrared lamp;

[0065] 5.0 μL of the Au@10 mM Ag NSs dispersion in Example 1 was added dropwise to the surface of a dried glassy carbon electrode (GCE) and allowed to dry naturally at room temperature to prepare an electrochemical biochiral sensor Au@10 mM AgNSs / GCE of a gold@silver nanostar composite material.

[0066] In this example, AuNSs / GCE and Au@(1 nM~1 mM)Ag NSs / GCE were prepared by the above method.

[0067] Performance testing:

[0068] In this example, the electrochemical properties of the sensor and GCE electrode prepared above were studied. The test process was as follows: a platinum sheet electrode (Pt, 10×5 mm) was used as the counter electrode, a silver / silver chloride electrode (Ag / AgCl) was used as the reference electrode, and a three-electrode system was constructed using bare GCE, AuNSs / GCE, Au@0.1 mM Ag NSs / GCE, Au@1 mM Ag NSs / GCE, and Au@10 mM Ag NSs / GCE as working electrodes, respectively. The above electrode system was placed in a 5 mM [Fe(CN)6] 4– / 3– The CV method was used to test the electrochemical window in the range of -0.2 to 0.6 V in a 0.1 M KCl solution at a scan rate of 100 mV / s (see the test results). Figure 8 ); at open circuit potential ~ 0.24V, frequency range is 10 5 ~0.01Hz to conduct EIS test (test results see Figure 9 ).

[0069] from Figure 8 It can be seen that all electrodes show a pair of very obvious redox peaks, which is caused by [Fe(CN)6] 3- and [Fe(CN)6] 4- Compared with the unmodified GCE, the conductivity of AuNSs is better, and the [Fe(CN)6] 4- / 3- The redox peak current value is large. When the silver shell grows on the surface of AuNSs, with the introduction of silver, the [Fe(CN)6] 4- / 3- The redox peak current increased significantly and gradually increased with the increase of AgNO3 concentration.

[0070] from Figure 9 It can be seen that different electrodes have different charge transfer resistances (R ct ) shows the following trend: R ct (GCE, 152Ω)>R ct (AuNSs / GCE, 124Ω)>R ct (Au@0.1mM Ag NSs / GCE, 101Ω)>R ct (Au@1mM AgNSs / GCE, 96Ω)>R ct (Au@10mM Ag NSs / GCE, 84Ω). Moreover, the trend of the EIS test is consistent with the CV test results.

[0071] Application Example 1

[0072] The present invention uses the sensor prepared in Example 2 to perform differential pulse voltammetry testing on a chiral amino acid solution. The specific process is as follows:

[0073] The sensor prepared in Example 2 was combined with a reference electrode (Ag / AgCl electrode) and a counter electrode (platinum electrode) to form a three-electrode system. The three-electrode system was immersed in 20 mL of 1 mM L-Trp and D-Trp in 0.1 M phosphate buffer (PBS, pH = 7.0), respectively. After standing for 10 s, differential pulse voltammetry (DPV) was performed in the potential range of 0.4 to 1.2 V. The oxidation peak current ratio (I L / I D ).

[0074] Figure 10 Shown is the relationship between the Ag concentration (45pM~0.45mM) in the Au@Ag NSs dispersion and I L / I D As can be seen from the figure, I L / I D There is an obvious corresponding relationship between the Ag concentration and the Ag concentration. In the figure, the Ag concentration is in the range of 45pM to 0.45mM. L / I D With Ag + The logarithm of the concentration showed a good linear relationship, and the regression equation was: y = -2.59 × 10 -2 lgx+0.87(R 2 =0.991), and the detection limit (LOD) was 24.5pM. The specific reason is that as the silver shell gradually thickens, the amount of L-AA oxidation product (L-DHA) bound to the surface of the material gradually increases, resulting in a gradual increase in its affinity for D-Trp. The oxidation peak current ratio of Trp enantiomers I L / I D Then it gradually decreases.

[0075] The above results prove that the electrochemical biosensor has different oxidation peak currents for amino acid enantiomers, so the chirality of amino acids can be determined by the oxidation peak potential.

[0076] Comparative Example 1:

[0077] The present invention further uses other metals (M) to replace Ag to prepare sensors. The preparation method is the same as that of Example 1-2. The metal source solution used is 10mM Fe 3+ 、Cu 2+ 、Zn 2+ and Co 2+ Nitrate solution; using differential pulse voltammetry to test the chiral recognition efficiency of the above sensor I L / ID Conduct a test.

[0078] The test results are as follows Figure 11 As shown, Ag + Chiral recognition efficiency of the prepared sensor for L-tryptophan (L-Trp) and D-tryptophan (D-Trp) L / I D reached 0.79, while other metal ions (Fe 3+ 、Cu 2+ 、Zn 2+ and Co 2+ ) The I measured by the sensor involved in the synthesis L / I D is about 1.00. This indicates that only Ag + The prepared sensor has significant differences in the oxidation peak potentials for L-tryptophan (L-Trp) and D-tryptophan (D-Trp). Therefore, the electrochemical biochiral sensor of the gold@silver nanostar composite material prepared in this application can recognize chiral amino acids.

[0079] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An electrochemical biochiral sensor based on a gold@silver nanostar composite material, characterized in that: The invention comprises an electrode matrix and a gold@silver nanostar composite material modified on the electrode matrix; the gold@silver nanostar composite material is a composite material with gold nanostar material as core and silver as shell.

2. The electrochemical biochiral sensor according to claim 1, characterized in that: The preparation method of the gold@silver nanostar composite material comprises the following steps: (1) heating chloroauric acid and trisodium citrate in an aqueous solution and subjecting them to reflux reaction for 10 to 20 minutes to prepare gold nanoparticles; (2) dispersing gold nanoparticles and N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) sodium salt buffer in water; adding chloroauric acid solution and stirring to react for 1 to 5 minutes; then adding hydroxylamine hydrochloride solution and continuing to stir and react for 10 to 20 minutes; after centrifugation and concentration, redispersing in N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) sodium salt buffer to obtain gold nanostar material; (3) After reacting ascorbic acid and the gold nanostar material in N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) sodium salt buffer for 1 to 5 minutes, a silver source is added and the reaction is continued for 3 to 7 minutes to obtain the gold@silver nanostar composite material.

3. The electrochemical biochiral sensor according to claim 2, characterized in that: In step (1), the molar ratio of the chloroauric acid solution to trisodium citrate is (1-100):(300-500); And / or, in step (2), the molar ratio of the sodium salt of N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) to chloroauric acid and hydroxylamine hydrochloride is (1-100):(1-5):(1-5); and / or, in step (2), the molar ratio of the gold nanoparticles to hydroxylamine hydrochloride is (1-5):(50-100); and / or, in step (3), the molar ratio of ascorbic acid to silver in the silver source is (1-5):(1-5); And / or, in step (3), the molar ratio of the gold nanostar material to Ag in the silver source is 1 to 11450000:

1.

4. The method for preparing an electrochemical biochiral sensor based on a gold@silver nanostar composite material according to any one of claims 1 to 3, characterized in that: The following steps are involved: The dispersed droplets of the gold@silver nanostar composite material are applied on an electrode substrate, and the electrochemical biological chiral sensor is obtained after the dispersion medium evaporates.

5. The preparation method according to claim 4, characterized in that The dispersion medium of the gold@silver nanostar composite material dispersion is N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) sodium salt buffer solution.

6. The preparation method according to claim 5, characterized in that In the gold@silver nanostar composite material, the concentration of Ag is 45 pM to 0.45 mM; And / or, the concentration of the N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) sodium salt buffer solution is 5-15 mM.

7. Use of the electrochemical biochiral sensor based on the gold@silver nanostar composite material according to any one of claims 1 to 3 in identifying amino acid enantiomers.

8. A method for identifying amino acid enantiomers, characterized in that: The following steps are involved: The electrochemical biochiral sensor based on the gold@silver nanostar composite material according to any one of claims 1 to 3 is incubated in a test amino acid solution, and then the oxidation peak current of the test amino acid solution is tested using differential pulse voltammetry under the electrochemical window.

9. The method according to claim 8, characterized in that The solvent of the amino acid solution to be tested is phosphate buffer; Preferably, the concentration of the amino acid in the amino acid solution to be tested is 0.5 to 2 mM; Preferably, the concentration of the phosphate buffer is 0.1 to 1 mol / L, and the pH is 6.0 to 8.0; Preferably, the voltage of the electrochemical window is 0.4-1.2V.

10. The method according to claim 8, characterized in that The amino acid enantiomers are amino acid enantiomers having electrochemical signals, including L-tryptophan and D-tryptophan, L-tyrosine (L-Tyr) and D-tyrosine.

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