Preparation method and application of electrochemical luminescence sensor for recognizing chiral amino acid isomer based on MOF-808-X material

Abstract

The invention relates to a preparation method and application of an electrochemical luminescence sensor for recognizing a chiral amino acid isomer based on an MOF-808-X material. According to the invention, an amino acid functionalized metal organic ligand complex MOF-808 is adopted to modulate chiral MOFs (CMOFs) attached with a chiral nano channel, and the chiral MOFs (CMOFs) is named as MOF-808-X. A classical three-electrode system is formed based on a working electrode of MOF-808-X; the amino acid with triple attributes is used as a detection object and a chiral functional molecule, and can also be used as a co-reactant to successfully form an ECL system with a chromophore, so as to construct an electrochemical luminescence molecular recognition sensor and application. Due to the recognition function of the chiral nano channel, the recognition of L and D configuration amino acids is efficiently, quickly, sensitively and selectively realized according to the difference of electrochemical luminescence intensity generated by L and D configurations.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method and application of an electrochemiluminescence sensor for identifying chiral amino acid isomers based on a MOF-808-X material, and belongs to the technical field of electrochemiluminescence specific identification and detection. BACKGROUND

[0002] Chirality is a common phenomenon in nature and is the essential attribute of life systems. Chirality is a characteristic that cannot be superimposed by mirror images. Chirality is commonly found in amino acids, sugars, nucleic acids, sugar units in starch and cellulose, proteins and DNA, etc. The efficacy of drugs and pesticides acting on organisms is often related to the chirality matching and chirality between them and target molecules in the body. Therefore, the research on chiral drugs and chiral pesticides is particularly important. Among the drugs used for treatment, many are chiral drugs. Different enantiomers of chiral drugs will show different efficacies in physiological processes. Especially when one enantiomer of a chiral drug is effective for treatment, and the other enantiomer shows harmful properties, the situation is more serious. Therefore, chirality identification is particularly important.

[0003] Commonly used techniques for chirality identification include high-performance liquid chromatography, fluorescence spectroscopy, circular dichroism spectroscopy, capillary electrophoresis, quartz crystal microbalance, etc. However, the above methods have limitations such as high cost, application of bulky instruments, inefficient testing process and complicated sample preparation. Because chiral molecules have the same chemical properties, the sensing voltage or current response caused by traditional electrochemical sensors is similar, which leads to poor sensitivity and low selectivity. Electrochemiluminescence (ECL) technology has attracted widespread attention due to its easy operation, no background interference, real-time detection and other characteristics. The introduction of light signals in electrochemiluminescence is conducive to the improvement of selectivity; the synchronous output of double signals improves the sensitivity; the light emission phenomenon on the electrode surface and the controllable modulation of voltage have the characteristics of high surface positioning controllability; and it is also conducive to the study of the mechanism of chemiluminescence reaction and electrochemical reaction, thereby providing an ideal choice for realizing chiral molecule recognition with high sensitivity, high selectivity and low cost.

[0004] The synthesis of materials with chiral properties can be used for chiral recognition. However, most chiral selectors have limited recovery rate, are expensive, and face great challenges in the synthesis process. Coordination between metal ions and chiral organic ligands can synthesize chiral metal-organic frameworks (CMOFs). CMOFs not only retain the large pore structure and high specific surface area of MOFs, but also have adjustable framework structures and determined crystal structures, and have a wide range of applications in the field of chiral-related research. Many studies have shown that CMOFs with chiral nanochannels or chiral pore structures have special recognition performance. According to the "three-point interaction theory", due to the differences in the interaction force and binding energy between the guest test amino acid and the host amino acid X, different effects are generated, which in turn cause different light emission intensities. According to the light emission intensity, the effect of chiral recognition is achieved. Therefore, CMOFs with chiral nanochannels provide a recognition working electrode for electrochemiluminescence sensors, and provide a new idea for realizing the recognition of chiral molecules. In this way, not only can the chiral template molecules be induced to form CMOFs with their own chiral recognition function in the nanochannels, but also the application of CMOFs in the field of electrochemiluminescence recognition can be expanded, and the development of electrochemiluminescence recognition technology can be promoted. SUMMARY

[0005] In view of the deficiencies of the prior art, the application provides a preparation method and application of an electrochemiluminescence sensor for recognizing chiral amino acid isomers based on MOF-808-X material. The application uses an amino acid functionalized metal-organic ligand complex MOF-808 to modulate a chiral MOF (CMOF) with a chiral nanochannel, which is named MOF-808-X. Based on the working electrode of MOF-808-X, a classic three-electrode system is formed; with a triple attribute amino acid as a chiral functional molecule, a detection object and a co-reactant successfully form an ECL system, and an electrochemiluminescence molecular recognition sensor is constructed and applied. Due to the recognition function of the chiral nanochannel, the electrochemiluminescence intensities generated by the detection of L and D configurations are different, and the L and D type amino acids are recognized with high efficiency, rapidness, high sensitivity and high selectivity. In order to achieve the above purpose, the technical scheme adopted by the application is as follows:

[0006] On the one hand, the application provides a preparation method of an electrochemiluminescence sensor for recognizing chiral amino acid isomers based on MOF-808-X material, which comprises coating a solution containing MOF-808-X material on a completely cleaned planar electrode, and drying at room temperature to form the sensor as a working electrode; wherein the MOF-808-X is a material with a chiral nanochannel structure formed by modifying a biological chiral molecule X into a channel of a metal-organic framework MOF-808.

[0007] As a preferred technical solution of the present application, the biological chiral molecule X is any one of L or D-histidine His, L or D-glutamic acid Glu, L or D-phenylalanine Phen, L or D-lysine Lys, L or D-cysteine Cys, L or D-proline Pro, L or D-lysine Lys, L or D-tyrosine Tyr.

[0008] As a preferred technical solution of the present application, the preparation method of the MOF-808-X material comprises:

[0009] S1. Dissolve 1,3,5-benzenetricarboxylic acid in DMF, dissolve zirconium oxychloride in formic acid, then mix and react the two solutions, heat and dry to obtain metal organic framework MOF-808;

[0010] S2. Place the metal organic framework MOF-808 in a mixed solution of EDC and NHS for coupling reaction to activate the carboxyl group;

[0011] S3. Dissolve the metal organic framework MOF-808 in a solution of the biological chiral molecule X, filter and dry the precipitate to obtain the MOF-808-X material.

[0012] As a preferred technical solution of the present application, the planar electrode is any one of glassy carbon, ITO, FTO, carbon cloth, and carbon fiber planar electrode.

[0013] As a preferred technical solution of the present application, the mass ratio of 1,3,5-benzenetricarboxylic acid to DMF in S1 is 1:70-100, the mass ratio of zirconium oxychloride to formic acid is 1:50-100, and the molar ratio of 1,3,5-benzenetricarboxylic acid to zirconium oxychloride is 1:1-2; the heating temperature is 100-160℃, and the reaction time is 1-5 days.

[0014] As a preferred technical solution of the present application, the mass ratio of the metal organic framework MOF-808 to EDC and NHS in S2 is 75-100:4:1.

[0015] On the other hand, the present application provides an application of the above-mentioned electrochemiluminescence sensor based on MOF-808-X material for recognizing chiral amino acid isomers, which is used for recognizing and detecting the chirality of amino acids and their isomers, and the steps comprise:

[0016] S1. Using cyclic voltammetry test method: the solution containing MOF-808-X material is coated on the completely cleaned planar electrode, and dried at room temperature to form the sensor as the working electrode, Ag / AgCl electrode as the reference electrode, and Pt wire electrode as the counter electrode,

[0017] S2. PBS buffer solution of amino acid molecules and chromophore group is configured;

[0018] S3. The working electrode, reference electrode and counter electrode are placed in the PBS buffer solution, a BPCL chemiluminescence measuring instrument is connected, a cyclic voltammetry scanning working voltage of 0-1.5V vs.Ag / AgCl is set, a scanning rate is 10-200mV / s, determination is carried out, and after data processing of an ECL signal, a chiral recognition result can be obtained.

[0019] As a preferred technical solution of the present application, the amino acid molecules in S2 are any one of L or D-tryptophan Trp, L or D-histidine His, L or D-glutamic acid Glu, L or D-phenylalanine Phen, L or D-lysine Lys, L or D-cysteine Cys, L or D-proline Pro, L or D-lysine Lys, and L or D-tyrosine Tyr.

[0020] As a preferred technical solution of the present application, the chromophore group in S2 is tetraphenylborate sodium TPB or Ru(bpy)3 2+ .

[0021] As a preferred technical solution of the present application, the concentration of the amino acid molecules in S2 is 10 -15 -10 -2 mol / L; the concentration of the chromophore group is 10 -5 -10 -2 mol / L; the concentration of the PBS buffer solution is 10 -5 -10 -2 mol / L; and the pH is 4-10.

[0022] By adopting the above technical solution, the present application has the following beneficial effects:

[0023] In the present application, MOF-808-X with chiral nanochannels is successfully synthesized. The synthesized MOF-808-X not only retains good conductivity and stability, but also is rich in chiral characteristics, and can be used for electrochemiluminescence chiral recognition. Taking MOF-808-His as an example, it is assembled into a working electrode, and an electrochemiluminescence molecular recognition sensor is constructed with a tryptophan Trp / TPB ECL system to recognize tryptophan isomers. In the recognition test, according to the different ECL signal strengths, the chiral recognition of tryptophan isomers is quickly, sensitively and efficiently realized. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 MOF-808-His prepared in Example 1 is used to test the ECL chiral recognition mechanism of tryptophan;

[0025] Figure 2CV and ECL plots for MOF-808-His / GCE recognition of D-Trp and L-Trp in Example 2;

[0026] Figure 3 ECL contrast plots for MOF-808-His / GCE recognition of D-Trp and L-Trp in Example 2;

[0027] Figure 4 CV and ECL plots for MOF-808-His / GCE recognition of D-Phen and L-Phen in Example 3. DETAILED DESCRIPTION

[0028] It should be noted that the following detailed description is merely exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0029] It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0030] Example 1

[0031] MOF-808-His was prepared to construct electrochemiluminescence chiral recognition sensor. The steps include:

[0032] S1, 5 x 10 -4 mol / L of 1,3,5-benzenetricarboxylic acid (C9H6O6) was dissolved in 11 mL of N, N-dimethylformamide (DMF), 5 x 10 -4 mol / L of zirconium oxychloride (ZrOCl2·8H2O) was dissolved in 11 mL of formic acid, and was transferred to a stainless steel reaction kettle with a tetrafluoroethylene liner and placed at 130°C for 2 days to obtain MOF-808 material; 0.16 g of the MOF-808 material and 0.05 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and 0.05 g of N-hydroxysuccinimide (NHS) were dissolved in 50 mL of distilled water, and stirred at room temperature for 3 hours; then L-histidine was dissolved in 8 mL of distilled water and added to the above solution, and stirred at room temperature for 4 hours; the sample was collected by filtration and dried in vacuum at room temperature for 12 h, and MOF-808-His was obtained after drying.

[0033] S2, 10 mol / L tryptophan (Trp) and 10 mmol / L sodium tetraphenylborate (TPB) or 5 mol / L other tryptophan (A) and 1 mmol / L Ru(bpy)3 2+ Dissolved in 10 mL of 100 mmol / L PBS buffer, successfully constituted the ECL system.

[0034] S3, MOF-808-X material was coated on the glassy carbon electrode to assemble the working electrode, Ag / AgCl was the reference electrode, and Pt wire was the counter electrode to build a three-electrode system, which was placed in the Trp / TPB or A / Ru(bpy)3 2+ solution, the electrochemiluminescence molecular recognition sensor was constructed to complete the detection, and the detection and recognition of chiral amino acid isomers were realized according to the analysis of ECL signal.

[0035] Example 2

[0036] The electrochemiluminescence molecular recognition sensor constructed in Example 1 was used for electrochemiluminescence recognition test of tryptophan isomers. The electrode was first placed in the PBS solution of tryptophan (Trp) for a certain time, and then placed in the PBS solution of TPB for direct test. The BPCL weak chemiluminescence analyzer device was used for ECL test, with the cyclic voltammetry potential set to 0-1.3V and the scan rate set to 50mV / s. The ECL signals of L / D-Trp were compared and tested, and the corresponding chiral recognition results were obtained after data processing.

[0037] According to the "three-point interaction theory", L and D configuration amino acid molecules can pass through the pore size channel of MOF-808-His, and the guest amino acid and the host amino acid X will produce different effects according to the different interaction forces and binding energies. Taking the host L-His as an example, it tends to form a diastereoisomer with D-Trp, and L-Trp is more likely to diffuse into the chiral channel and diffuse to the electrode surface to undergo oxidation reaction, and further react with the oxidized TPB intermediate TPB · to emit stronger light. Conversely, D-Trp produces weak light, and the chiral recognition effect is achieved according to the light intensity.

[0038] As shown in Figure 2 , it can be seen from the CV curve that TPB has an oxidation peak at 0.48V vs Ag / AgCl, represented by a black line. The oxidation peak of tryptophan Trp is at 0.8V vs Ag / AgCl, which proves that both of them undergo oxidation reaction on the electrode; and the oxidation peak current obtained in the L-Trp solution is stronger than that in the D-Trp; and the ECL signal is represented by a blue line.

[0039] As shown in Figure 3 , the comparison chart of ECL shows that 10 -2ECL intensity ratio (R ECL ) of 13.24, the ECL signal of L-Trp on MOF-808-His / GCE showed stronger ECL signal than that of D-Trp, which indicated that more L-Trp could be adsorbed on the chiral channel of MOF-808-His and migrated to the electrode surface to undergo oxidation reaction compared with D-Trp, and further reacted with the oxidized TPB intermediate TPB · to generate a strong ECL signal.

[0040] In summary, in this embodiment, MOF-808 was prepared into MOF-808-His with chiral nanochannels. The synthesized MOF-808-His not only retained good conductivity and stability, but also was rich in chiral characteristics, and could be used for electrochemiluminescence chiral recognition. When MOF-808-His recognized tryptophan isomers, the tryptophan isomers could be quickly, sensitively and efficiently recognized according to the different ECL signal strengths.

[0041] Example 3

[0042] According to Example 1, other types of electrochemiluminescence molecular recognition sensors were constructed.

[0043] MOF-808-His was coated on a glassy carbon electrode to assemble a working electrode. L or D-phenylalanine (Phen) and a chromophore Ru(bpy)3 2+ were used to form a Phen / Ru(bpy)3 2+ system. The electrode was first placed in a PBS solution of cysteine (Phen) for 30 s, and then placed in a PBS solution of Ru(bpy)3 2+ for direct testing. The ECL test was performed using a BPCL device, with a cyclic voltammetry potential of 0-1.3 V and a scan rate of 50 mV / s. After comparing the ECL signals of L / D-Phen and processing the data, the corresponding chiral recognition results were obtained.

[0044] As shown in Figure 4 , it is an ECL comparison chart of the electrochemiluminescence molecular recognition sensor for testing phenylalanine (Phen) constructed using MOF-808-His. Figure 4 a shows the CV-ECL schematic diagram of 10 -2 M of L-Phen / Ru(bpy)3 2+ ; Figure 4 b shows the CV-ECL schematic diagram of 10 -2 M of D-Phen / Ru(bpy)3 2+ ; the ECL intensity of the red line in the two figures was compared (R ECL) is about 2, and the current difference is small from the CV curve, but the light signal shows that the ECL signal of L-Phen on the MOF-808-His / GCE is stronger than that of D-Phen, and MOF-808-His can make more L-Phen on the electrode surface to occur oxidation reaction, further and the oxidized Ru(bpy)3 2+ Intermediate Ru(bpy)3 3+ The "redox" type ECL reaction path occurs, a stronger ECL signal is generated, and the recognition of phenylalanine isomers is realized.

[0045] The above are only some embodiments of the present application, and do not limit the present application in any form, and any simple modification, equivalent change and modification made on the basis of the technical essence of the application to the above embodiments all belong to the technical solution range of the present application.

Claims

1. A method for preparing an electrochemiluminescence sensor for identifying chiral amino acid isomers based on MOF-808-X material, characterized in that: The method comprises applying a solution containing MOF-808-X material onto a completely cleaned planar electrode and drying the solution at room temperature to form the sensor as a working electrode. The MOF-808-X is a material having a chiral nanochannel structure formed by modifying a biochiral molecule X into the channel of a metal-organic framework MOF-808.

2. The method according to claim 1, characterized in that The biochiral molecule X is any one of L or D-histidine His, L or D-glutamic acid Glu, L or D-phenylalanine Phen, L or D-lysine Lys, L or D-cysteine ​​Cys, L or D-proline Pro, L or D-lysine Lys, and L or D-tyrosine Tyr.

3. The method according to claim 1, characterized in that The preparation method of the MOF-808-X material comprises: S1. Dissolve 1,3,5-benzenetricarboxylic acid in DMF and zirconium oxychloride in formic acid. Mix the two solutions and heat and dry to obtain a metal organic framework MOF-808. S2. The metal organic framework MOF-808 was placed in a mixture of EDC and NHS for a coupling reaction to activate the carboxyl groups; S3. dissolving the metal organic framework MOF-808 in the solution of the biochiral molecule X, filtering the precipitate and drying it to obtain the MOF-808-X material.

4. The method according to claim 1, wherein The planar electrode is any one of glassy carbon, ITO, FTO, carbon cloth, and carbon fiber planar electrodes.

5. The method according to claim 3, characterized in that The mass ratio of the 1,3,5-benzenetricarboxylic acid to the DMF in S1 is 1:70-100, the mass ratio of the zirconium oxychloride to formic acid is 1:50-100, and the molar ratio of the 1,3,5-benzenetricarboxylic acid to zirconium oxychloride is 1:1-2; the heating temperature is 100-160° C., and the reaction time is 1-5 days.

6. The method according to claim 3, characterized in that The mass ratio of the metal organic framework MOF-808 to EDC and NHS in S2 is 75-100:4:

1.

7. A method for preparing an electrochemiluminescence sensor for recognizing the chirality of amino acid isomers based on MOF-808-X material according to any one of claims 1 to 6, characterized in that: Used for enantiomer recognition detection of amino acid isomers, the steps include: S1. Cyclic voltammetry test method: A solution containing MOF-808-X material is applied to a completely cleaned planar electrode and dried at room temperature to form a drop of MOF-808-X on the planar electrode as the working electrode, an Ag / AgCl electrode as the reference electrode, and a Pt wire electrode as the counter electrode. S2. Prepare PBS buffer solution containing amino acid molecules and chromophores; S3. Place the working electrode, reference electrode, and counter electrode in the PBS buffer solution, connect them to a BPCL weak chemiluminescence measuring instrument, set the cyclic voltammetry scanning working voltage to 0-1.5V vs. Ag / AgCl, and perform the measurement at a scan rate of 10-200mV / s. After data processing of the ECL signal, the chiral recognition result can be obtained.

8. The method according to claim 7, characterized in that The amino acid molecule in S2 is any one of L or D-tryptophan Trp, L or D-histidine His, L or D-glutamate Glu, L or D-phenylalanine Phen, L or D-lysine Lys, L or D-cysteine ​​Cys, L or D-proline Pro, L or D-lysine Lys, and L or D-tyrosine Tyr.

9. The method according to claim 7, characterized in that The chromophore in S2 is sodium tetraphenylborate TPB or Ru(bpy)3 2+ .

10. The method according to claim 7, characterized in that The amino acid molecule concentration in S2 is 10 -15 ~10 - 2 mol / L; the chromophore concentration is 10 -5 ~10 -2 mol / L; PBS buffer concentration is 10 -5 ~10 -2 mol / L; pH is 4-10.

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