CN113004315A

CN113004315A - Histidine-triggered organic hydrogel fluorescent probe and preparation method and application thereof

Info

Publication number: CN113004315A
Application number: CN202110175668.XA
Authority: CN
Inventors: 牛和林; 刘文胜; 杨勇; 廉笑
Original assignee: Anhui University
Current assignee: Anhui University
Priority date: 2021-02-09
Filing date: 2021-02-09
Publication date: 2021-06-22
Anticipated expiration: 2041-02-09
Also published as: CN113004315B

Abstract

The invention discloses a histidine-triggered organic hydrogel fluorescent probe, a preparation method and application thereof, wherein histidine is used as a fluorescence trigger, Zr⁴⁺Using N, N-dimethylformamide and H as precursor and gel inducer₂And O is used as a mixed solvent to construct a histidine-triggered metal-organic hydrogel fluorescent switch probe Zr-MOG-His. The kit is used for stably, selectively and sensitively detecting and capturing the residual vitamins, amino acids and antibiotics in water, and the detection result shows specificity to Rutin (RUT), beta-Carotene (CAR), Vancomycin (VHE) and nitrofurantoin (FAN), good fluorescence change efficiency, excellent detection limit and practicability.

Description

Histidine-triggered organic hydrogel fluorescent probe and preparation method and application thereof

Technical Field

The invention relates to the field of material chemistry and sensing, in particular to a histidine-triggered organic hydrogel fluorescent probe and a preparation method and application thereof.

Background

The development of multifunctional fluorescent probes is crucial to the selection and optimization of optical sensor substrate materials. Luminescent metal organogels, which are a kind of emerging metal-organic hybrid materials having both partial characteristics of metal-organic complexes and colloids, are drawing attention, and have been gradually applied to the field of optical sensors.

Vitamins are essential trace elements for maintaining normal physiological functions of human beings, and have important functions and efficacies on the life health of human beings. Rutin (vitamin P, Rut) is a flavonoid vitamin that the human body needs to take, and is used for eliminating excessive free radicals in the human body. It has subtle effects on the development of various body systems and the removal of disease factors. However, while Rut is beneficial to humans, such as allergic populations, obese patients and those with weak capillaries are not suitable for excessive intake of such substances, it is also noteworthy that rutin is more severely harmful to aquatic organisms. Beta-carotene, as a class of classical carotenoids, is effective in preventing diseases such as cancer, but when mistakenly added to some foods, such as fried foods, toxic and side effects are generated on human bodies. Antibiotics are broad-spectrum drugs used to treat human diseases and bacterial infections. Vancomycin and nitrofurantoin are used as two types of commonly used anti-staphylococcus aureus and sensitive bacteria medicaments and are often used in clinical medicine. However, two antibiotics have been banned from being added to food. The effect of illegal addition to food to preserve the freshness of the food is a common practice of illegal merchants. Therefore, it is essential to effectively detect food additives and antibiotics in such foods.

The optical sensor has the advantages of high recognition efficiency, visual effect and good expression effect. Fluorescence sensors based on fluorescence quenching mode are a very classical class of optical detectors that have been favored by many researchers. In addition, fluorescence sensors based on the fluorescence enhancement mode have been drawing attention from researchers due to their excellent characteristics such as sensitivity. Both have advantages and disadvantages. In the method, a multifunctional fluorescence sensor is constructed by taking metal organic gel as an optical substrate material and is used for detecting and identifying the common food additives and antibiotics.

Disclosure of Invention

Histidine (His) is a human bodyThe essential basic amino acid contains carboxylic acid and a plurality of N binding sites, and has very important functions of adjusting human body homeostasis, acid-base balance, controlling inflammatory reaction and improving human body immunity. The invention takes His as a fluorescence opening 'key', and provides a zirconium-based metal organogel Zr-MOG-His which is triggered by amino acid and has coordination induced luminescence effect for specifically and sensitively identifying and capturing Rut aiming at the defects of the existing experience and technology, such as electrochemical method, colorimetric method, chromatography and the like. The electron-rich structure of His forms a good bridging site with strong competitiveness with trimesic acid. His is used as a good Lewis base in the system to play a role in regulating pH, reducing the acidic environment of the system and promoting the formation of a gel system. The acidic environment is easy to cause His protonation, and the positively charged N-containing functional group blocks Zr⁴⁺Indirectly induce Zr⁴⁺Forming a stable interaction force with-COO-.

A method for preparing histidine triggered organic hydrogel fluorescent probe uses histidine as fluorescent trigger and Zr⁴⁺Using N, N-dimethylformamide and H as precursor and gel inducer₂And O is used as a mixed solvent to construct a histidine-triggered metal-organic hydrogel fluorescent switch probe Zr-MOG-His.

The preparation method comprises the steps of mixing DMF and H₂O into the reaction vessel and then shaken well until mixed completely, DMF and H₂The volume ratio of O is 3:5-9: 1; adding ligand into the reaction vessel, mixing and dissolving; fully shaking the reaction vessel for 10-30min until the organic ligand in the system is completely dissolved, and then adding 0.05mmoL-1moL of Zr⁴⁺Adding into the mixed solvent; heating and shaking the reaction system, then putting the reaction system into an electric heating forced air drying oven, and heating the reaction system for 30min-12h at the temperature of 80-120 ℃ to form white columnar gel.

In the preparation method, the ligand is trimesic acid, terephthalic acid, graphene quantum dots, perovskite quantum dots, melamine, g-C₃N₄And organic acid or inorganic-organic hybrid nanodots having a plurality of carboxyl groups or amino groups.

According to the preparation method, the ligand is trimesic acid, and the molar ratio of His to trimesic acid is 1:1

The preparation method, DMF and H₂The volume ratio of O is 7: 3.

The organic hydrogel fluorescent probe prepared by any one of the preparation methods.

The organic hydrogel fluorescent probe is applied to detecting and capturing residual vitamins, amino acids and antibiotics in water stably, selectively and high sensitively, and the detection result shows specificity to Rutin (RUT), beta-Carotene (CAR), Vancomycin (VHE) and nitrofurantoin (FAN), good fluorescence change efficiency, excellent detection limit and practicability.

Adding DMF and H₂O into the reaction vessel and then shaken well until mixed completely, DMF and H₂The volume ratio of O is 7:3 (any mixing ratio of 3:5-9: 1); the ligand of the trimesic acid can be replaced by terephthalic acid, graphene quantum dots, perovskite quantum dots, melamine, g-C₃N₄Organic acid or inorganic-organic hybrid nanodots having a plurality of carboxyl groups or amino groups) is added into the reaction vessel, and the molar ratio of His to trimesic acid is 1:1 (the molar ratio can be adjusted arbitrarily as required, the photoluminescence behavior of other amino acids for forming gel is verified or excluded through a large number of experiments, the experimental result shows that the other amino acids except tryptophan, tyrosine, phenylalanine, arginine and histidine do not have obvious photoluminescence behavior in the wavelength range of 300-500nm after forming metal organic gel, and the experimental recorded data are shown in Table 1) are mixed and dissolved. His here as a basic bridging ligand with Zr⁴⁺Coordinate, thereby triggering the effect of Zr-MOG-His fluorescence turn-on. Fully shaking the reaction vessel for 10-30min until the organic ligand in the system is completely dissolved, and then adding Zr⁴⁺(salt which can be fully dissolved or dispersed in a mixed solvent of DMF and water and is between 0.05mmoL and 1 moL) is added into the mixed solvent; heating and vibrating the reaction system, then placing the reaction system into an electric heating forced air drying oven, heating the reaction system for 30min-12h at the temperature of 80-120 ℃ (the heating temperature is inversely proportional to the time, the higher the temperature is, the shorter the synthesis time is, the synthesis temperature is controlled within 25-170 ℃), and formingWhite column gel, heating time depends on material ratio and other conditions. The His-triggered coordination-induced luminescent metal organogel prepared by the preparation method is subjected to fluorescence starting after the gel is formed, and the fluorescence starting efficiency is enhanced according to the increase of the concentration of His; meanwhile, rutin, beta-carotene, vancomycin and nitrofurantoin have good stimulus response on the freeze-dried xerogel so as to generate quenching effect, and L-alanine and D-arginine have certain fluorescence enhancement effect on the freeze-dried xerogel.

Table 1 metal organogel formed by partial amino acids and its luminescence mechanism

The invention has the following advantages:

1. the target detection object can be specifically identified in water or serum;

2. the fluorescent switch probe induces luminescence by coordination, and the fluorescence of the probe is switched on by the coordination induced luminescence effect of a ligand to metal. And the effects of rapidly identifying and capturing rutin, beta-carotene, vancomycin and nitrofurantoin are achieved through energy resonance transfer or internal filtration effect.

3. The fluorescent probe is mixed with other food additives or antibiotics for detection, the detection effect of a target detection object is still not influenced, and the quenching effect is instantly finished due to the internal filtration effect between a subject and an object or the synergistic effect of energy resonance transfer, so that the fluorescent probe has the advantages of rapid detection, sensitivity and good selectivity.

Drawings

FIG. 1 is a diagram of an optical representation of a Zr-MOG-His gel;

FIG. 2 is a UV optical diagram of a Zr-MOG-His gel;

FIG. 3 optimization experiment of histidine to BTC ratio;

FIG. 4 scanning electron microscope and transmission electron microscope pictures of Zr-MOG-His xerogel;

FIG. 5(a) structural formula of histidine (b) structural formula of trimesic acid;

FIG. 6 structural formulas of target detection species and target antibiotics;

FIG. 7(a) fluorescence emission spectra of Zr-MOG-His xerogel recognizing different kinds of food additives, (b) concentration gradient fluorescence emission spectra captured by Zr-MOG-His xerogel versus Rut recognition, (c) Rut linear fitting spectra;

FIG. 8(a) fluorescence change efficiency of Zr-MOG-His xerogel recognizing different kinds of antibiotics, (b) concentration gradient fluorescence emission spectrum captured by Zr-MOG-His xerogel versus FAN recognition, (c) FAN linear fitting map;

FIG. 9 solid state UV absorption spectra of Zr-MOG-His xerogel, BTC, His, Rut, Zr-MOG-His + Rut;

FIG. 10 solid state fluorescence lifetime before and after Zr-MOG-His xerogel recognition and capture Rut;

Detailed Description

The present invention will be described in detail with reference to specific examples.

Example 1:

the specific implementation steps for preparing Zr-MOG-His are as follows:

1. hydrothermal solvothermal method: adding DMF and H₂O was mixed in any ratio and transferred to a glass vial, followed by shaking thoroughly until complete mixing. BTC (0.1g, 0.05mmol) and His were added separately to a glass vial. And (4) carrying out ultrasonic oscillation treatment on the small glass bottle for 20s-3min until the ligand in the system is completely dispersed and dissolved. Then ZrCl is added₄(0.046g, 0.2mmol) was added to the mixed solvent. Finally, the reaction system is put into an electric heating forced air drying oven and heated for 30min to 12h at the temperature of 80 to 120 ℃ to form white columnar gel. The gel is then eluted with double distilled water or ethanol. In a high speed centrifuge at 12000r min^-1High speed centrifugation was used to aid in the removal of residual DMF from the gel. Finally, the eluted hydrogel was placed in a freeze-drying oven and dried under vacuum at-110 ℃ to further remove residual DMF and non-crystallized H from the gel₂O。

2. An ultrasonic-assisted thermal method: the specific reactant amounts are as above. And (3) placing the fully mixed and dissolved precursor in an ultrasonic heater, and carrying out ultrasonic heating to obtain white columnar gel.

3. A microwave-assisted method: the specific reactant dosage is the same as above, and the reaction vessel is replaced by a reaction kettle and a polytetrafluoroethylene lining. And (3) fully mixing the dissolved precursors, placing the mixture into a microwave oven, and heating the mixture by microwaves to obtain white columnar gel.

Optimization of His to BTC ratio

Weighing a certain amount of His and BTC according to different molar ratios, respectively, and pouring DMF and H₂And (4) fully shaking the mixture of the O and the solvent in a small glass bottle until the mixture is completely dissolved. Then phase mass ZrCl₄Adding into the glass bottle. Stir well at room temperature until completely dissolved. And finally, fully sealing the mixed precursor, and then placing the precursor in an electric heating blowing drying oven to heat for 12 hours at the temperature of 120 ℃. Obtaining Zr-MOG-His with His being BTC in different proportions. The residual DMF is removed by treatment and washing with double distilled water and absolute ethanol 3-10 times respectively. The experimental results show that the fluorescence intensity is highest when the ratio is 1:1 (FIG. 3).

Example 2: detection of Rut by Zr-MOG-His as fluorescent probe

The dried gel of the Zr-MOG-His hydrogel after freeze drying is used for Rut detection. Zr-MOG-His xerogel (100mg) was dispersed in 5mL of H₂And in O or DMSO, ultrasonically shaking for 30min until the dispersion is complete. The finished dispersion was formulated for use in the identification capture experiment.

100 μ L of Zr-MOG-His was removed to centrifuge tubes containing solutions of various analytes of interest (2.9mL) and incubated at room temperature for 30-60 min. After the Zr-MOG-His and the target analyte are completely mixed, the Zr-MOG-His is used for the subsequent stimulation response experiment of the target detection object to the Zr-MOG-His. Fluorescence spectra were recorded by excitation at 370 nm.

Selective recognition of rutin and beta-carotene (taking rutin as an example)

The His BTC optimized gel is used for a rutin stimulation response experiment after freeze-drying xerogel. Zr-MOG-His xerogel (200mg) was dispersed in 5mL DMF and ultrasonically dispersed for 20-50min until completely dispersed. The finally obtained dispersion is used for a stimulus response experiment on rutin.

500 μ L of Zr-MOG-His was transferred to centrifuge tubes containing different target assay solutions and incubated at room temperature for 30 min. And finally, the obtained mixed dispersion liquid is used for selective verification of rutin. The following food additives were selected as target analytes for rutin for the selectivity experiments: rutin (RUT), Carotene (CAR), L-aspartic acid (L-Asp), L-valine (L-Val), L-glutamic acid (L-Ula), L-histidine (L-His), DL-arginine (DL-Arg), melamine (Mel), sucrose (Suc), glucose (Glu), D-fructose (D-Fru), lactose (Lac), L-leucine (L-Lea), L-methionine (L-Met), L-isoleucine (L-Iso).

As can be seen from fig. 7(a), different food additives have different degrees of quenching effect, wherein the RUT and CAR significantly quench the fluorescence of Zr-MOG-His with higher fluorescence quenching efficiency. In addition, it is noteworthy that the relative fluorescence intensity of Zr-MOG-His shows a linear decrease with increasing RUT concentration (FIG. 7 b). According to the Stern-Volmer (SV) equation: f₀/F＝1+K_SV[M]And the standard calculation formula LOD of the detection limit is 3 sigma/K_SVThe value of Ksv and LOD are estimated. In the formula, F₀And F is the fluorescence intensity of the Zr-MOG-His gel dispersion before and after addition of a concentration of RUT. [ M ] A]Is the molar concentration of Zr-MOG-His gel, and K_SVIs the quenching constant, and σ is the standard deviation of the amount of blank. In conjunction with FIG. 7c, the detection limit of RUT was calculated to be 0.011 μ M, thus having good practical potential and lower sensitivity.

As can be seen from FIG. 7, rutin has excellent stimulation response results to Zr-MOG-His, and the energy resonance transfer efficiency is up to 97.4% according to the fluorescence lifetime. This may be attributed to the strong interaction between host (Zr-MOG-His) and guest (Rut) leading to fluorescence resonance energy transfer. This view is further demonstrated by the extensive integration overlap between the fluorescence emission spectrum of the Zr-MOG-His xerogel and the UV absorption spectrum of Rut. In addition, after the Zr-MOG-His xerogel identifies the Rut, an obvious absorption band appears in the solid ultraviolet absorption spectrum of the Zr-MOG-His xerogel at about 350nm-500nm, which implies that a certain interaction is formed between the Zr-MOG-His xerogel and the Rut, which may be attributed to the stable conjugated structure of the Zr-MOG-His xerogel, namely BTC, and the stable pi-pi interaction is formed between the His and the Rut, so that the Zr-MOG-His xerogel can selectively capture the Rut and generate a fluorescence turn-off signal. According to the fluorescence lifetime before and after identification, a static quenching mechanism between the host and the guest is excluded (the static quenching does not cause the change of the fluorescence lifetime). The Zr-MOG-His xerogel becomes a sensing material which can selectively identify and capture rutin and has great potential.

Example 3: selectively identifying antibiotics vancomycin and nitrofurantoin (taking nitrofurantoin as an example), wherein the operation steps are as follows, and the specific target antibiotics are selected as follows:

procaine Penicillin (PPG), Thiamphenicol (TPL), Vancomycin Hydrochloride (VHE), Azithromycin (ATN), Ceftazidime (CAE), cefoxitin sodium (CXN), Cefuroxime (CRM), penicillin sodium (PCN), Cefixime (CIE), Amoxicillin (AMO), Aztreonam (AEM), Clarithromycin (CTN), Tinidazole (TDE), Metronidazole (MIE), nitrofurantoin (FAN).

Different antibiotics have different degrees of quenching or fluorescence enhancement effect, wherein FAN significantly quenches the fluorescence of Zr-MOG-His with higher fluorescence quenching efficiency (fig. 8 a). In addition, it is noteworthy that the relative fluorescence intensity of Zr-MOG-His shows a linear decrease with increasing FAN concentration (FIG. 8 b). According to the Stern-Volmer (SV) equation: f₀/F＝1+K_SV[M]And the standard calculation formula LOD of the detection limit is 3 sigma/K_SVThe value of Ksv and LOD are estimated. In the formula, F₀And F is the fluorescence intensity of the Zr-MOG-His gel dispersion before and after the addition of a certain concentration of FAN. [ M ] A]Is the molar concentration of Zr-MOG-His gel, and K_SVIs the quenching constant, and σ is the standard deviation of the amount of blank. In conjunction with FIG. 7c, the FAN detection limit was calculated to be 0.597. mu.M, and thus it was found that Zr-MOG-His has a good ability to recognize FAN.

It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.

Claims

1. A preparation method of histidine-triggered organic hydrogel fluorescent probe is characterized in that histidine is used as a fluorescence trigger, and Zr is used⁴⁺Using N, N-dimethylformamide and H as precursor and gel inducer₂And O is used as a mixed solvent to construct a histidine-triggered metal-organic hydrogel fluorescent switch probe Zr-MOG-His.

2. The method according to claim 1, wherein DMF and H are added₂O into the reaction vessel and then shaken well until mixed completely, DMF and H₂The volume ratio of O is 3:5-9: 1; adding ligand into the reaction vessel, mixing and dissolving; fully shaking the reaction vessel for 10-30min until the organic ligand in the system is completely dissolved, and then adding 0.05mmoL-1moL of Zr⁴⁺Adding into the mixed solvent; heating and shaking the reaction system, then putting the reaction system into a drying oven, and heating the reaction system for 30min-12h at the temperature of 80-120 ℃ to form white columnar gel.

3. The method according to claim 2, wherein the ligand is trimesic acid, terephthalic acid, graphene quantum dots, perovskite quantum dots, melamine, g-C₃N₄And organic acid or inorganic-organic hybrid nanodots having a plurality of carboxyl groups or amino groups.

4. The method according to claim 3, wherein the ligand is trimesic acid, and the molar ratio of His to trimesic acid is 1: 1.

5. the method according to claim 4, wherein DMF and H are₂The volume ratio of O is 7: 3.

6. The organic hydrogel fluorescent probe prepared by the preparation method according to any one of claims 1 to 5.

7. The use of the organic hydrogel fluorescent probe according to claim 6 for detecting and capturing residual vitamins, amino acids and antibiotics in water stably, selectively and with high sensitivity, and the detection results show specificity to Rutin (RUT), beta-Carotene (CAR), Vancomycin (VHE), nitrofurantoin (FAN), good fluorescence change efficiency, excellent detection limit and practicality.