Electrochemically modified electrode for light-enhanced chiral recognition as well as preparation and application of electrochemically modified electrode

Abstract

The invention belongs to the technical field of electrochemical recognition, and particularly relates to an electrochemical modified electrode for light-enhanced chiral recognition as well as preparation and application of the electrochemical modified electrode. In order to improve the sensitivity of electrochemical chiral recognition and recognizable molecule types, tetrabutyl titanate is used as a raw material, a photonic crystal with a TiO2 inverse opal structure is prepared on a polystyrene opal template, R-type or S-type 1, 1 '-co-2-naphthol chiral modification molecules are modified on the inverse opal structure, and the photonic crystal with the TiO2 inverse opal structure is obtained. And preparing the light-enhanced chiral recognition electrochemical modified electrode. The electrochemical modified electrode has a recognition effect on aromatic chiral molecules and aliphatic chiral molecules, and the recognition effect on the chiral molecules is enhanced under wavelength illumination of an absorption sideband of the photonic crystal.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical recognition technology, and particularly relates to an electrochemically modified electrode for photo-enhanced chiral recognition, its preparation and application. Background Technology

[0002] Chirality is a fundamental characteristic of living organisms, and the basic life processes of organisms are essentially the result of single-chiral selection. For example, the basic building blocks of organisms, proteins and nucleic acids, both possess chiral structures. Furthermore, many small biological molecules essential for maintaining basic life activities, such as amino acids and carbohydrates, also exhibit chiral characteristics. Enantiomers with different chiralities can elicit drastically different physiological responses in living organisms, a phenomenon particularly common in the field of chiral drugs. Drugs with a single chirality typically exhibit well-defined pharmacological activity; however, their enantiomers may have significantly different effects, or even produce toxicity or adverse reactions. Therefore, chiral recognition, especially highly sensitive recognition of molecules with low chiral content, is of great significance in many fields, including life sciences, pharmaceutical science, synthetic chemistry, and materials science.

[0003] Electrochemical methods have become an effective chiral recognition technique due to their advantages of simple operation, low cost, high sensitivity, and ease of on-site detection. Most existing electrochemical chiral recognition techniques are based on the principle of stereointeractions. Different enantiomers interact differently with chiral-modified working electrodes, resulting in differences in electrochemical signal magnitude, thus distinguishing the chirality of two enantiomers. In these methods, the chiral recognition capability mainly depends on the affinity of the chiral-modified working electrode. Therefore, developing chiral working electrodes with high affinity, including electrodes modified with chiral small molecules, functional macromolecules, supramolecular materials, and nanomaterials, is a prerequisite for achieving high-performance enantiomer recognition (CN120468245A). In recent years, spin-electrochemical chiral recognition techniques based on the spin-selectivity effect of chiral molecules have also been developed. The spin selectivity of chiral molecules refers to the fact that electrons with a certain spin orientation are more easily transported than electrons with the opposite orientation when a charge passes through a chiral molecule, resulting in a spin-polarized current after passing through the chiral molecule. These identification technologies typically employ chiral modified electrodes under non-magnetic field conditions or magnetic working electrodes under magnetic field conditions to generate polarization currents with specific spin orientations. Since chiral molecules have spin filtering capabilities, target enantiomers with different chiralities have different transmission efficiencies for spin polarization currents, generating distinguishable electrical signals, thereby enabling the identification of enantiomers.

[0004] Electrochemical chiral recognition methods based on the principle of stereochemical interactions, such as the technical solution described in Chinese patent "CN120468245A A method for preparing and applying chiral serine-modified graphynylene," rely on the affinity of chiral modified molecules. They typically require the preparation of functional chiral molecules with specific structures to modify the working electrode, thus imposing high requirements and limitations on the synthesis process of chiral modified molecules and the preparation process of the working electrode. Furthermore, different types of chiral molecules have different structures, resulting in varying affinity energies with chiral modified molecules. Therefore, these methods are often suitable for the recognition of enantiomers of one or a few types of chiral molecules, lacking versatility. Chiral spin-dependent electrochemical methods, on the other hand, distinguish between two enantiomers based on the spin selectivity of chiral molecules, thus this type of chiral recognition is generally more universal. However, due to the inherently weak chirality of chiral molecules, especially small chiral molecules, their spin filtering effect is insignificant and their spin selectivity is poor. Therefore, the recognition ability for these molecules is generally low, manifesting not only as weak recognition signals but also limited recognition sensitivity. Summary of the Invention

[0005] To address the above problems, this invention provides an electrochemically modified electrode for photoenhanced chiral recognition, its preparation, and its application.

[0006] The present invention provides an electrochemically modified electrode for photo-enhanced chiral recognition, comprising a photonic crystal and chiral modifying molecules modified on the photonic crystal. The photonic crystal has an inverse opal structure, and the chiral modifying molecules are R-type or S-type 1,1'-bi-2-naphthol.

[0007] The photonic crystal has a TiO2 inverse opal structure, composed of TiO2, exhibiting a layered structure, with each layer having a uniform and regular hexagonal pore structure.

[0008] The photo-enhanced chiral recognition electrochemically modified electrode has the ability to recognize both aromatic and aliphatic chiral molecules; aromatic chiral molecules include phenylalanine, phenylglycine, and phenyllactic acid; aliphatic chiral molecules include lysine, arginine, glutamic acid, aspartic acid, tartaric acid, tyrosine, and tryptophan.

[0009] Irradiation with light at the absorption sideband wavelength of the TiO2 inverse opal structure (photonic crystal) can amplify the response electrical signal during the recognition process of the chiral molecule to be tested, thereby enhancing the recognition ability of the electrochemically modified electrode for photo-enhanced chiral recognition of the chiral molecule to be tested; irradiation with a 532nm laser is preferred.

[0010] The present invention discloses a method for preparing an electrochemically modified electrode for photoenhanced chiral recognition, comprising the following steps: uniformly attaching polymer microspheres to the surface of a conductive glass substrate to obtain an opal template; immersing the opal template in a tetrabutyl titanate solution, wherein the tetrabutyl titanate is converted into TiO2 and forms a TiO2 coating layer on the surface of the opal template; removing the polymer microspheres to obtain a TiO2 inverse opal structure; and modifying the TiO2 inverse opal structure with R-type or S-type 1,1'-bi-2-naphthol to obtain the electrochemically modified electrode for photoenhanced chiral recognition.

[0011] The above preparation method includes the following specific steps: vertically immersing an ITO conductive glass substrate into a uniformly dispersed suspension of polymer microspheres, heating to evaporate the solvent while the polymer microspheres uniformly adhere to the surface of the conductive glass substrate, thus obtaining a self-assembled face-centered cubic polymer microsphere opal template; the polymer microspheres include polystyrene microspheres, polymethyl methacrylate microspheres, hydrogel microspheres, etc., and the particle size range of the polymer microspheres is 200 nm to 1000 nm;

[0012] The solvent in the suspension consists of ethanol and water, the concentration of the polymer microspheres in the suspension is 0.2 wt%, and the heating temperature is 30℃; the solvent in the tetrabutyl titanate solution is ethanol and water, the volume ratio of tetrabutyl titanate, ethanol and deionized water is 5:10:4, and the pH of the solution is adjusted to 1~2 with hydrochloric acid;

[0013] After forming a TiO2 coating on the surface of the opal template, the template was removed from the solution and heated to 450°C at a rate of 2°C / min, held for 180 min, and the polystyrene microspheres were removed to obtain anatase TiO2 inverse opal structure attached to a conductive glass substrate. When the polymer microspheres are 280 nm polystyrene microspheres, the pore size of the prepared TiO2 inverse opal structure is about 200 nm, and the absorption sideband wavelength of the TiO2 inverse opal structure is about 532 nm.

[0014] TiO2 inverse opal structure was immersed in an ethanol solution of R-type or S-type 1,1'-bi-2-naphthol for 12 h, with a 10 oz concentration of 10 oz. –3 1,1'-bi-2-naphthol was used to modify the TiO2 inverse opal structure with mol / L, resulting in a light-enhanced modified electrode that can be used for electrochemical chiral recognition.

[0015] The present invention relates to an application of an electrochemically modified electrode for photo-enhanced chiral recognition, comprising the following: using an electrochemically modified electrode for photo-enhanced chiral recognition as the working electrode, a platinum wire as the counter electrode, and an Ag / AgCl electrode as the reference electrode to form a three-electrode system; adding a mixture of potassium ferrocyanide, potassium ferrocyanide, and potassium chloride as the electrolyte to the three-electrode system to construct an electrochemical chiral recognition system; adding an enantiomer of the chiral molecule to be tested; and using differential pulse voltammetry to identify the chiral type of the chiral molecule to be tested.

[0016] The chiral type of the enantiomer of the target chiral molecule is identified by the change in the oxidation peak current of the potassium ferrocyanide / potassium ferrocyanide redox couple. When a photo-enhanced chiral recognition modified electrode made of R-type 1,1'-bi-2-naphthol is used as the working electrode, the oxidation peak current values ​​of the enantiomers of the target chiral molecule are compared. The molecule with the higher oxidation peak current value is a D-type chiral molecule, and the molecule with the lower oxidation peak current value is an L-type chiral molecule. When a photo-enhanced chiral recognition modified electrode made of S-type 1,1'-bi-2-naphthol is used as the working electrode, the oxidation peak current values ​​of the enantiomers of the target chiral molecule are compared. The molecule with the higher oxidation peak current value is an L-type chiral molecule, and the molecule with the lower oxidation peak current value is a D-type chiral molecule.

[0017] The total concentration of potassium ferricyanide and potassium ferrocyanide in the electrolyte was 2.5 mmol / L, and the concentration of potassium chloride was 0.5 mol / L. When the chiral molecules to be tested were identified by differential pulse voltammetry under 532 nm laser irradiation, the potential was -0.2 V to 0.6 V, and the scan rate was 4 mV / s. The concentration of the chiral molecules to be tested in the identification system was 0.05 mmol / L to 1.50 mmol / L.

[0018] This invention provides a highly sensitive and universal electrochemical chiral recognition method based on the light-regulating properties of photonic crystal structures. According to the scheme of this invention, a photonic crystal with a specific aperture and absorption sideband matching the irradiation light can be prepared by adjusting the size of polymer microspheres according to the existing wavelength of irradiation light. Alternatively, the wavelength of the irradiation light can be adjusted according to the structure of the existing photonic crystal. The chiral-modified photonic crystal with a specific size serves as the working electrode. Under illumination of its absorption sideband wavelength, the slow photon effect generated by the photonic crystal can significantly promote the charge transfer process at the electrode interface, thereby increasing the spin polarization of electrons and enhancing enantiomeric selectivity. While maintaining the high universality of the chiral spin electrochemical method, it effectively amplifies the current signal response during the enantiomeric recognition process, improving the chiral recognition sensitivity. The method of this invention overcomes the technical bottleneck of the difficulty in balancing sensitivity and universality in existing electrochemical chiral recognition technologies.

[0019] This invention utilizes the photoenhancing effect to improve the sensitivity and universality of electrochemical chiral recognition. The method is simple to operate and exhibits high recognition performance, enabling effective identification of enantiomers of different chiral molecules. Furthermore, this method is not only applicable to the prepared 200nm pore size TiO2 inverse opal working electrode, but can also be used to prepare TiO2 inverse opal structures with different pore sizes and responses to different wavelengths of light by selecting PS microsphere templates of different particle sizes according to actual needs, in order to match the required wavelength of light irradiation and achieve photoenhanced electrochemical chiral recognition under different wavelength conditions. This invention significantly enhances the electrochemical chiral recognition capability through light irradiation, possessing not only good recognition sensitivity but also high universality. It is applicable to both aromatic chiral molecules with strong chirality and enantiomer recognition of aliphatic chiral molecules that are difficult to effectively identify using other existing electrochemical chiral recognition technologies. The method is simple to operate, has good recognition results, and can meet the needs of various practical application fields. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the electrochemical chiral recognition system test.

[0021] Figure 2 Morphology diagram of polystyrene opal template;

[0022] Figure 3 Morphology diagram of the inverse opal structure of TiO2;

[0023] Figure 4 XRD pattern of TiO2 inverse opal structure;

[0024] Figure 5 The reflectance spectrum of the inverse opal structure of TiO2;

[0025] Figure 6 Raman spectra of modified electrodes with S-1,1'-bi-2-naphthol and S-1,1'-bi-2-naphthol-modified TiO2 inverse opal structures for enhanced chiral recognition.

[0026] Figure 7 Circular dichroism chromatogram of a modified electrode for photoenhanced chiral recognition of TiO2 inverse opal structure, modified with S-1,1'-bi-2-naphthol and R-1,1'-bi-2-naphthol.

[0027] Figure 8 Differential pulse voltammetry test results for 10 batches of S-1,1'-bi-2-naphthol-modified TiO2 inverse opal photoenhanced chiral recognition modified electrodes;

[0028] Figure 9The differential pulse voltammetry results for the D-tryptophan and L-tryptophan chiral enantiomers on a modified electrode of S-1,1'-bi-2-naphthol-modified TiO2 inverse opal with enhanced chiral recognition under no-light conditions.

[0029] Figure 10 The image shows the differential pulse voltammetry test results of the modified electrode for photoenhanced chiral recognition of D-tryptophan and L-tryptophan chiral molecules on TiO2 inverse opal modified with S-1,1'-bi-2-naphthol under 532nm laser irradiation.

[0030] Figure 11 The graph shows the oxidation peak current ratio of different concentrations of D-tryptophan and L-tryptophan chiral enantiomers to a modified electrode of S-1,1'-bi-2-naphthol-modified TiO2 inverse opal photoenhanced chiral recognition under 532nm laser irradiation.

[0031] Figure 12 The graph shows the oxidation peak current ratios of different chiral molecule enantiomers to the modified electrode of TiO2 inverse opal photoenhanced chiral recognition under 532nm laser irradiation. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. It should be noted that the embodiments described in this invention are only for further explanation and illustration, and not for limiting their application scope. Based on this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention.

[0033] Example 1

[0034] S1 photo-enhanced chiral recognition electrochemically modified electrode:

[0035] The electrochemically modified electrode for photoenhanced chiral recognition in this embodiment consists of a TiO2 inverse opal structure and R-type or S-type 1,1'-bi-2-naphthol chiral modification molecules modified onto the TiO2 inverse opal structure. The TiO2 inverse opal exhibits a layered structure, with each layer possessing a uniform, regular hexagonal pore structure with a pore size of 200 nm. It has the ability to recognize aromatic chiral molecules such as phenylalanine, phenylglycine, and phenyllactic acid, as well as aliphatic chiral molecules such as lysine, arginine, glutamic acid, aspartic acid, tartaric acid, tyrosine, and tryptophan. Under 532 nm laser irradiation, the response electrical signal during the recognition process of the target chiral molecule can be amplified, enhancing the recognition capability.

[0036] S2 is used to prepare electrochemically modified electrodes for photoenhanced chiral recognition:

[0037] S2-1 Preparation of polystyrene opal template: Taking the preparation of opal template using polystyrene microspheres with a diameter of 280 nm as an example.

[0038] Take 800 μL of a 2.50% polystyrene microsphere mixture with a diameter of 280 nm and add it to a 1.00 mL centrifuge tube. Add 200 μL of a 1:1 (v / v) ethanol-water mixture and centrifuge at 11000 rpm and 8°C for 10 min to separate the polystyrene microspheres from the liquid phase. Take the supernatant and add 1 mL of a 1:1 ethanol-water mixture. Sonicate for 5 min to mix thoroughly to obtain a polystyrene microsphere mixture. Repeat the above steps 8 times. Finally, disperse the polystyrene microspheres in 1 mL of a 1:1 ethanol-water mixture. Dilute the polystyrene microspheres in the mixture to a concentration of 0.2 wt% with deionized water and then sonicate at 0°C for 1 h to obtain a polystyrene microsphere suspension.

[0039] In a 5 mL petri dish, a 4 mL suspension of polystyrene microspheres was ultrasonically dispersed. An ITO conductive glass substrate was then vertically immersed in the suspension. The petri dish was placed in a 30°C digital display drying oven and heated until the solvent was completely evaporated, forming a self-assembled face-centered cubic polystyrene opal template on the ITO conductive glass substrate. The morphology of the prepared polystyrene opal template is shown in the figure. Figure 2 As shown, the polystyrene microspheres have an average particle size of 280 nm and are densely and orderly packed on an ITO conductive glass substrate.

[0040] S2-2 Preparation of TiO2 inverse opal structure: TiO2 inverse opal structure was obtained by impregnation and calcination.

[0041] Mix 0.5 mL of tetrabutyl titanate, 0.2 mL of hydrochloric acid, 1 mL of ethanol, and 0.4 mL of deionized water to prepare a tetrabutyl titanate solution. Immerse a polystyrene opal template in the tetrabutyl titanate solution. The solution penetrates into the pores of the opal template through capillary force. The tetrabutyl titanate undergoes hydrolysis and condensation reactions to generate TiO2, and then forms a TiO2 template with the polystyrene opal template as a substrate.

[0042] Hydrolysis: nTi(OR)₄ + 4H₂O → nTi(OH)₄ + 4nROH

[0043] Condensation: nTi(OH)4 → nTiO2 + 2nH2O

[0044] The generated TiO2 template was left to age overnight, and then calcined in a muffle furnace at 450℃ for 180 min (heating rate of 2℃ / min) to remove the polystyrene opal template, resulting in an anatase TiO2 inverse opal structure attached to an ITO conductive glass substrate.

[0045] The morphology of the prepared TiO2 inverse opal structure is as follows: Figure 3 As shown, it exhibits a layered structure, with each layer consisting of a uniform, regular hexagonal pore structure. The diameter of each hexagon is approximately 200 nm, smaller than the diameter of polystyrene microspheres. This is due to the shrinkage and collapse of the system during the calcination of the inverse opal. The X-ray diffraction pattern of the TiO2 inverse opal structure is shown below. Figure 4 As shown, the diffraction peaks at 25.4°, 38.2°, 48.3°, 54.1°, 55.2°, 63.0°, 70.4°, 75.4°, and 82.9° correspond to the (101), (004), (200), (105), (211), (204), (220), (215), and (224) crystal planes of the anatase phase TiO2, indicating that the prepared TiO2 inverse opal has the anatase crystal form. The reflection spectrum of the TiO2 inverse opal structure is shown in the figure. Figure 5 As shown, its maximum reflection wavelength is approximately 460 nm, and 532 nm light is located at its absorption sideband.

[0046] S2-3 modified chiral molecules: R-type or S-type 1,1'-bi-2-naphthol is modified onto the TiO2 inverse opal structure.

[0047] The concentration is configured to be 10. –3 mol·L –1 An R-type or S-type 1,1'-bi-2-naphthol ethanol solution (R / S-BINOL) was used to immerse a TiO2 inverse opal structure attached to an ITO conductive glass substrate in the R / S-1,1'-bi-2-naphthol solution for 12 hours, thereby modifying the TiO2 inverse opal structure with R-type or S-type 1,1'-bi-2-naphthol. After rinsing several times with deionized water and drying in an N2 environment, an electrochemically modified electrode with enhanced chiral recognition was obtained.

[0048] Figure 6 In the Raman spectrum, at 438 cm⁻¹ –1 851cm –1 and 1589cm –1 Coupled vibrational modes of CH out-of-plane bending and CC twisting, CH out-of-plane bending and CCC in-plane bending, and CC stretching and OH bending, corresponding to R or S type 1,1'-bi-2-naphthol molecules, were observed at 1379 cm⁻¹. –1The in-plane CO stretching vibration mode observed at the site confirms that the chiral modified molecule R or S-type 1,1'-bi-2-naphthol has been successfully modified on the surface of the TiO2 inverse opal structure through bonding. Figure 7 Circular dichroism (CD) analysis showed that the prepared TiO2 inverse opal structure was not chiral, and only became chiral after its surface was modified with chiral recognition molecules R-type 1,1'-bi-2-naphthol or S-type 1,1'-bi-2-naphthol.

[0049] Applications of S3 photo-enhanced chiral recognition electrochemically modified electrodes:

[0050] S3-1 Construction of an electrochemical chiral recognition system: An electrochemically modified electrode with photo-enhanced chiral recognition was used as the working electrode, a 0.5 mm diameter platinum wire as the counter electrode, and an Ag / AgCl electrode as the reference electrode, forming a three-electrode system. The electrolyte consisted of K3[Fe(CN)6] / K4[Fe(CN)6] with a total concentration of 2.5 mmol / L and 0.5 mol / L... A mixed solution of KCl was used to construct an electrochemical chiral recognition system.

[0051] S3-2 Electrochemical Chiral Recognition Test: Enantiomers of the target chiral molecules were added to two identical electrochemical chiral recognition systems at a concentration of 0.5 mmol / L, with a power density of 0.14 W / cm². 2 Under 532nm laser irradiation, the differential pulse voltammetry method was used to identify the chiral molecules to be tested. A schematic diagram of the test is shown below. Figure 1 As shown. Differential pulse voltammetry was performed in the potential range of -0.2V to 0.6V at a scan rate of 4mV / s. All tests were repeated three times to ensure the reliability and repeatability of the data. The chirality of enantiomers was identified by detecting the difference in oxidation peak current values ​​in the differential pulse voltammetry spectra of the two chiral molecules in the enantiomer system.

[0052] Example 2

[0053] This embodiment uses an electrochemically modified electrode of TiO2 inverse opal with S-1,1'-bi-2-naphthol modified with photoenhanced chiral recognition as an example to conduct electrochemical chiral recognition tests. Unless otherwise specified, all other tests are conducted using the same methods as in Example 1. The test contents include the reproducibility of the electrochemically modified electrode with photoenhanced chiral recognition, the effect of light on chiral recognition, the effect of enantiomeric concentration, and the universality.

[0054] Reproducibility testing: Taking the S-1,1'-bi-2-naphthol-modified TiO2 inverse opal structure as an example, 10 batches of photo-enhanced chiral recognition electrochemically modified electrodes were prepared, and electrochemical chiral recognition tests were performed. The results are as follows: Figure 8As shown, the test spectra of different batches are basically overlapping, indicating that the modified electrode of TiO2 inverse opal photoenhanced chiral recognition modified by S-1,1'-bi-2-naphthol has good batch reproducibility.

[0055] Chiral recognition test without light irradiation: The electrochemical chiral recognition system was tested using a modified electrode (S-1,1'-bi-2-naphthol modified TiO2 inverse opal) to enhance chiral recognition. The system used D-tryptophan and L-tryptophan as enantiomers of the target chiral molecules, with each concentration of D-tryptophan and L-tryptophan being 1 mmol / L. The results of the differential pulse voltammetry test are shown below. Figure 9 As shown, the oxidation peak current ratio I L / I D The value of 1.145 indicates that the modified electrode for light-enhanced chiral recognition prepared in this invention has a certain recognition ability for the enantiomers of the chiral molecules to be tested under no-light conditions.

[0056] Photoluminescent chiral recognition test: Under 532 nm light irradiation, the electrochemical chiral recognition system was tested using a modified electrode of S-1,1'-bi-2-naphthol-modified TiO2 inverse opal with photoenhanced chiral recognition. The test system used D-tryptophan and L-tryptophan as enantiomers of the target chiral molecules, with concentrations of 1 mmol / L for both D-tryptophan and L-tryptophan. The results of differential pulse voltammetry are shown below. Figure 10 As shown, the oxidation peak current ratio I L / I D The value of 1.432 indicates that the electrochemically modified electrode for photo-enhanced chiral recognition prepared in this invention significantly enhances the recognition performance of the enantiomers of the chiral molecules to be tested under illumination.

[0057] Chiral recognition tests at different concentrations: Under 532 nm light irradiation, the electrochemical chiral recognition system was tested using a modified electrode of TiO2 inverse opal modified with S-1,1'-bi-2-naphthol to enhance chiral recognition. The test system used D-tryptophan and L-tryptophan as enantiomers of the target chiral molecules, with concentrations of 0.05 mmol / L, 0.10 mmol / L, 0.30 mmol / L, 0.50 mmol / L, 1.00 mmol / L, and 1.50 mmol / L, respectively. Differential pulse voltammetry was used to measure the oxidation peak current, and the ratio of oxidation peak currents at different enantiomer concentrations was compared. The results are as follows: Figure 11 As shown, even at a low concentration of 0.05 mmol / L, the photo-enhanced chiral recognition electrochemically modified electrode of the present invention still possesses significant electrochemical chiral recognition capability.

[0058] Universality Testing: Under 532nm laser irradiation, the universality of the photo-enhanced electrochemically modified electrode for chiral recognition was tested using enantiomers of ten chiral molecules—lysine (Lys), arginine (Arg), glutamic acid (Glu), aspartic acid (Asp), tartaric acid (TA), phenylalanine (Phe), phenylglycine (Phg), tyrosine (Tyr), tryptophan (Trp), and phenyllactic acid (PLA)—as examples. In the test system, the concentration of each chiral molecule was 1.00 mmol / L. The oxidation peak current was measured using differential pulse voltammetry, and the ratio of oxidation peak currents in different chiral molecule recognition systems was compared. The results are as follows: Figure 12 As shown, the electrochemically modified electrode for photo-enhanced chiral recognition of the present invention not only has good recognition ability for aromatic chiral molecules with strong chirality, but also exhibits good recognition ability for aliphatic chiral molecules with weak chirality, thus having universality.

Claims

1. An electrochemically modified electrode for light-enhanced chiral recognition, characterized in that, The electrochemical modified electrode is composed of a photonic crystal and a chiral modifier molecule modified on the photonic crystal, the photonic crystal is a reverse opal structure, and the chiral modifier molecule is R-type or S-type 1,1'-binaphthyl.

2. The electrochemically modified electrode for chiral recognition by light enhancement according to claim 1, wherein, The electrochemical modified electrode has recognition ability for both aromatic chiral molecules and aliphatic chiral molecules; under the absorption edge wavelength light irradiation of the photonic crystal, the response electrical signal in the chiral molecule recognition process can be amplified, and the recognition ability of the electrochemical modified electrode for the chiral molecule to be detected can be strengthened.

3. The electrochemically modified electrode for chiral recognition by light enhancement according to claim 2, wherein, The aromatic chiral molecules include phenylalanine, phenylglycine and phenyllactic acid; and the aliphatic chiral molecules include lysine, arginine, glutamic acid, aspartic acid, tartaric acid, tyrosine and tryptophan. The photonic crystal is a TiO2 reverse opal structure, which is composed of TiO2 and has a layered structure, and each layer is a uniform and regular hexagonal hole structure; and the absorption edge wavelength light irradiation is 532 nm laser irradiation.

4. The method according to claim 1, wherein the method is characterized by, The method comprises the following steps: uniformly attaching polymer microspheres to the surface of a conductive glass substrate to obtain a protein crystal template; immersing the protein crystal template in a tetrabutyl titanate solution, so that the tetrabutyl titanate is converted into TiO2 and a TiO2 covering layer is formed on the surface of the protein crystal template; and removing the polymer microspheres to obtain a TiO2 reverse opal structure; and modifying R-type or S-type 1,1'-binaphthyl on the TiO2 reverse opal structure to obtain an electrochemical modified electrode for light-enhanced chiral recognition.

5. The method according to claim 4, wherein the method is characterized by, The method comprises the following steps: vertically immersing an ITO conductive glass substrate in a uniformly dispersed polymer microsphere suspension, and heating to evaporate the solvent and uniformly attach the polymer microspheres to the surface of the conductive glass substrate to obtain a self-assembled face-centered cubic arranged polymer microsphere protein crystal template. The polymer microspheres include polystyrene microspheres, polymethyl methacrylate microspheres and hydrogel microspheres; and the particle size of the polymer microspheres is 200 nm to 1000 nm. The method comprises the following steps: immersing the TiO2 reverse opal structure in an ethanol solution of R-type or S-type 1,1'-binaphthyl, so that the 1,1'-binaphthyl is modified on the TiO2 reverse opal structure to obtain the electrochemical modified electrode.

6. The method according to claim 5, wherein the method is characterized by, The solvent of the polymer microsphere suspension includes ethanol and water, the concentration of the polymer microspheres in the suspension is 0.2 wt%, and the heating temperature is 30°C; the pH of the tetrabutyl titanate solution is 1 to 2, and the solvent includes ethanol and water. When the polymer microspheres are polystyrene microspheres, after the TiO2 covering layer is formed on the surface of the protein crystal template, the polystyrene microspheres are removed by heat treatment at 450°C for 180 min to obtain a sharp titania reverse opal structure attached to the conductive glass substrate.

7. The method according to claim 5, wherein the method is characterized by, When the polymer microspheres are 280 nm polystyrene microspheres, the pore size of the TiO2 reverse opal structure is 200 nm, and the absorption edge wavelength of the TiO2 reverse opal structure is 532 nm.

8. The use of an electrochemically modified electrode for optical enhancement of chiral recognition according to claim 1, wherein, The electrochemical modified electrode is used as a working electrode, a platinum wire is used as a counter electrode, and an Ag / AgCl electrode is used as a reference electrode to form a three-electrode system; an electrolyte is added to the three-electrode system to build an electrochemical chiral recognition system, and an enantiomer of a chiral molecule to be detected is added, and a differential pulse voltammetry method is used to recognize the chiral type of the chiral molecule to be detected.

9. The use of a photo-enhanced chiral recognition electrochemically modified electrode according to claim 8, characterized in that, The electrolyte comprises potassium ferricyanide, potassium ferrocyanide and potassium chloride; and the oxidation peak current of the enantiomer is compared to recognize the chiral type of the chiral molecule to be detected. When the chiral modified molecule is R-type 1,1'-binaphthyl-2-ol, the enantiomer with a high oxidation peak current value is a D-type chiral molecule, and the enantiomer with a low oxidation peak current value is an L-type chiral molecule; when the chiral modified molecule is S-type 1,1'-binaphthyl-2-ol, the enantiomer with a high oxidation peak current value is an L-type chiral molecule, and the enantiomer with a low oxidation peak current value is a D-type chiral molecule.

10. The use of a photo-enhanced chiral recognition electrochemically modified electrode according to claim 9, characterized in that, In the electrolyte, the total concentration of the potassium ferricyanide and the potassium ferrocyanide is 2.5 mmol / L, the concentration of the potassium chloride is 0.5 mol / L, and the concentration of the enantiomer is 0.05 mmol / L to 1.50 mmol / L; when the chiral molecule to be detected is recognized by using the differential pulse voltammetry method under 532 nm laser irradiation, the potential is -0.2 V to 0.6 V, and the scanning rate is 4 mV / s.

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