A near-infrared fluorescent probe for identifying erythromycin and a preparation method and application thereof

Abstract

This invention relates to the field of fluorescence sensing technology, and discloses a near-infrared fluorescent probe for identifying erythromycin, its preparation method, and its application. The structural formula of the fluorescent probe is as follows: The near-infrared fluorescent probe is obtained by reacting ethyl 2-(3-aldehyde-4-hydroxyphenyl)-4-methylthiazolium-5-carboxylate with 6-amino-3,4-dihydro-1(2H)-naphthone. This invention also relates to the application of the near-infrared fluorescent probe in the detection of erythromycin. The near-infrared fluorescent probe provided by this invention is simple to synthesize and apply, and can achieve rapid and sensitive detection of erythromycin in solution, showing broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of fluorescent probe technology for antibiotic detection, specifically to a fluorescent probe for naked-eye detection of erythromycin, its preparation method, and its application. Background Technology

[0002] Erythromycin is a broad-spectrum macrolide antibiotic containing 14 membered lactone rings, 10 asymmetric centers, and 2 carbon molecules. It is used to treat various bacterial infections, including respiratory infections, skin infections, chlamydia, pelvic inflammatory disease, and syphilis. Globally, the annual consumption of antibiotics exceeds 100,000 tons, and excess erythromycin remains in surface water and animal-derived foods. However, in humans, erythromycin is harmful to the colonic flora. Furthermore, erythromycin is included on the EU's watch list as a high-risk detection substance. Therefore, effective monitoring of erythromycin is of great significance for human health and environmental protection.

[0003] Currently, widely used methods for erythromycin detection include ultraviolet spectrophotometry, microbiological methods, optical rotation detection, high-performance liquid chromatography (HPLC), and electrochemical detection. While these methods are relatively mature and reliable, they also suffer from drawbacks such as complex operation, expensive instruments, and difficult maintenance, and cannot provide real-time monitoring. In recent years, fluorescence detection analysis methods based on chemical sensors have attracted significant attention due to their simplicity, high selectivity and sensitivity, rapid analysis time, non-destructive nature, and intuitive, convenient visual qualitative and quantitative identification.

[0004] In recent years, there have been few reports on fluorescent probes for detecting erythromycin, and the reported probes have complicated synthesis steps, low selectivity and sensitivity, which greatly limits their application. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of cumbersome probe synthesis steps, low selectivity, and low sensitivity in existing technologies, and to provide a near-infrared fluorescent probe for recognizing erythromycin, its preparation method, and its application.

[0006] To achieve the above objectives, the first aspect of the present invention provides a near-infrared fluorescent probe for recognizing erythromycin, wherein the fluorescent probe has the following structural formula:

[0007]

[0008] A second aspect of the present invention provides a method for preparing a near-infrared fluorescent probe according to the first aspect, wherein the method comprises: reacting ethyl 2-(3-aldehyde-4-hydroxyphenyl)-4-methylthiazol-5-carboxylate with 6-amino-3,4-dihydro-1(2H)-naphthone to obtain the near-infrared fluorescent probe.

[0009] A third aspect of the present invention provides the application of the near-infrared fluorescent probe according to the first aspect or the near-infrared fluorescent probe prepared according to the method of the second aspect in the detection of erythromycin.

[0010] The beneficial technical effects achieved by the present invention through the above technical solution are as follows:

[0011] 1) The near-infrared fluorescent probe provided by this invention can be synthesized in just one step, with inexpensive raw materials and simple post-processing.

[0012] 2) This invention enables the sensing and detection of erythromycin via a probe based on changes in fluorescence color, exhibiting good selectivity. Furthermore, the fluorescence intensity ratio is directly proportional to the erythromycin concentration, and the detection limit for erythromycin in solution is 9.80 × 10⁻⁶. -8 M, highly sensitive.

[0013] 3) Compared to other fluorescent probes for detecting erythromycin in solution, the probe provided by this invention can detect erythromycin through a significant change in fluorescence color. Therefore, the probe provided by this invention is simple to synthesize and apply, enabling rapid and sensitive detection of erythromycin in solution, and has broad application prospects. Attached Figure Description

[0014] Figure 1 This is the solid-state fluorescence spectrum of the near-infrared fluorescent probe TPMC of Example 1 of the present invention;

[0015] Figure 2 The fluorescence spectra of the near-infrared fluorescent probe TPMC of Example 1 of the present invention in EtOH / H2O mixed solvents with different water contents are shown.

[0016] Figure 3 The near-infrared fluorescent probe TPMC (concentration of 1×10⁻⁶) is from Example 1 of this invention. -5 Fluorescence selectivity spectra of different antibiotics in the EtOH / H2O system (mol / L);

[0017] Figure 4 The near-infrared fluorescent probe TPMC (concentration of 1×10⁻⁶) is from Example 1 of this invention. -5 Fluorescence spectrum response of erythromycin at different concentrations (mol / L) in EtOH / H2O system;

[0018] Figure 5 The near-infrared fluorescent probe TPMC (concentration of 1×10⁻⁶) is from Example 1 of this invention. -5 Linear fluorescence response of erythromycin at different concentrations (mol / L) in an EtOH / H2O system;

[0019] Figure 6The effect of coexisting antibiotics on the determination of erythromycin by the near-infrared fluorescent probe TPMC in Example 1 of this invention. Detailed Implementation

[0020] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0021] The first aspect of this invention provides a near-infrared fluorescent probe TPMC for recognizing erythromycin, wherein the structural formula of the fluorescent probe is as follows:

[0022]

[0023] The near-infrared fluorescent probe TPMC described in this invention is a covalently bonded compound of ethyl 2-(3-aldehyde-4-hydroxyphenyl)-4-methylthiazol-5-carboxylate and 6-amino-3,4-dihydro-1(2H)-naphthone, which can be identified by naked eye through changes in fluorescence color.

[0024] The near-infrared fluorescent probe TPMC described in this invention can be prepared by a one-step synthesis method. The TPMC probe emits strong orange-red fluorescence in the solid state, and in the EtOH-H2O system, the fluorescence gradually red-shifts with increasing water content, indicating that the probe exhibits an AIE effect. The TPMC probe of this invention emits strong red fluorescence in an EtOH-H2O (1 / 9, v / v, pH=7.4) solution; upon interaction with erythromycin, the solution fluorescence changes from red to green. However, the addition of other antibiotics does not show significant changes in solution fluorescence, indicating that the TPMC probe has high selectivity for erythromycin. Furthermore, fluorescent titration of erythromycin with the probe shows that the solution color changes from orange-red to yellow to yellow-green to green with increasing erythromycin concentration, indicating that the TPMC probe can visually sense erythromycin.

[0025] A second aspect of the present invention provides a method for preparing a near-infrared fluorescent probe according to the first aspect, wherein the method comprises: reacting ethyl 2-(3-aldehyde-4-hydroxyphenyl)-4-methylthiazol-5-carboxylate with 6-amino-3,4-dihydro-1(2H)-naphthone to obtain the near-infrared fluorescent probe.

[0026] In some embodiments of the present invention, the method includes the following steps:

[0027] (1) 2-(3-aldehyde-4-hydroxyphenyl)-4-methylthiazol-5-carboxylic acid ethyl ester, 6-amino-3,4-dihydro-1(2H)-naphthone and the catalyst were dissolved in an organic solvent to obtain a mixed solution;

[0028] (2) Heat the mixed solution obtained in step (1) under reflux to react;

[0029] (3) After the reaction is complete, cool to room temperature and a red precipitate will be formed. After filtration, washing and drying, the near-infrared fluorescent probe is obtained.

[0030] In the preparation process of the near-infrared fluorescent probe described in this invention, the following reaction occurs:

[0031]

[0032] In some embodiments of the present invention, the molar ratio of ethyl 2-(3-aldehyde-4-hydroxyphenyl)-4-methylthiazol-5-carboxylate to 6-amino-3,4-dihydro-1(2H)-naphthone in step (1) is 1:1.

[0033] In some embodiments of the present invention, the catalyst is glacial acetic acid.

[0034] In some embodiments of the present invention, the organic solvent is ethanol.

[0035] In some embodiments of the present invention, the heating temperature in step (2) is 80-90°C.

[0036] In some embodiments of the present invention, the reaction time is 5-6 hours.

[0037] In some embodiments of the present invention, the reaction is monitored using a TLC plate (thin-layer chromatography plate) in step (3).

[0038] In some embodiments of the present invention, the washing is performed by washing with ethanol 2-3 times.

[0039] A third aspect of the present invention provides the application of the near-infrared fluorescent probe according to the first aspect or the near-infrared fluorescent probe prepared according to the method of the second aspect in the detection of erythromycin.

[0040] In some embodiments of the present invention, the near-infrared fluorescent probe is used for sensing and detecting the content of erythromycin in an aquatic environment system.

[0041] In some embodiments of the present invention, the sensing detection is colorimetric fluorescence detection or visual qualitative detection.

[0042] According to a particularly preferred embodiment of the present invention, a method for preparing a near-infrared fluorescent probe includes:

[0043] Ethyl 2-(3-aldehyde-4-hydroxyphenyl)-4-methylthiazol-5-carboxylate, 6-amino-3,4-dihydro-1(2H)-naphthone, and the catalyst were dissolved in ethanol, and glacial acetic acid was added dropwise. The mixture was heated to reflux at 80-90°C for 5-6 hours. The reaction was monitored by TLC. After the reaction was complete, the mixture was cooled to room temperature, and a red precipitate was formed. The precipitate was filtered, washed 2-3 times with ethanol, and dried to obtain the near-infrared fluorescent probe TPMC.

[0044] The molar ratio of ethyl 2-(3-aldehyde-4-hydroxyphenyl)-4-methylthiazol-5-carboxylate to 6-amino-3,4-dihydro-1(2H)-naphthone is 1:1.

[0045] The present invention will be described in detail below through embodiments.

[0046] Unless otherwise specified in the following examples and comparative examples, all conditions were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0047] Example 1

[0048] Synthesis of a near-infrared fluorescent probe TPMC for recognizing erythromycin:

[0049]

[0050] Ethyl 2-(3-aldehyde-4-hydroxyphenyl)-4-methylthiazolium-5-carboxylate (291 mg, 1 mmol) and 6-amino-3,4-dihydro-1(2H)-naphthone (161 mg, 1 mmol) were dissolved in 20 mL of ethanol. Two drops of glacial acetic acid were added as a catalyst, and the mixture was heated to reflux at 80 °C for 6 h. The reaction was monitored by TLC. After the reaction was complete, the mixture was cooled to room temperature, and a red precipitate was formed. The precipitate was filtered, washed 2-3 times with ethanol, and dried to obtain the near-infrared fluorescent probe TPMC with a yield of 65%.

[0051] Its NMR and mass spectrometry data are as follows:

[0052] 1 H NMR(TFA-d6,CDCl3-d6 and MeOH-d6,600MHz)δ10.14(s,1H),8.45(s,1H),8.15(m,2H),7.96(q,1H),7.43(t,1H),7.18(q,1 H),5.73(s,1H),4.45(m,2H),3.42(t,2H),3.06(t,2H),2.87(d,3H),2.18(t,2H),1.42(t,3H).13 CNMR(TFA-d6,CDCl3-d6 and MeOH-d6,100MHz)δ195.51,170.70,167.58,167.49,146.61,137.04,135.05,134.53,131.62,131.51,128.82,1 28.58,126.65,123.78,123.71,123.22,121.14,120.88,118.17,61.56,20.26,15.12,12.67.HRMS:m / z[TPMC+H] + ,found:435.1385.

[0053] Test Example 1

[0054] The near-infrared fluorescent probe TPMC from Example 1 was subjected to solid-state fluorescence testing, emitting orange-red fluorescence at a wavelength of 610 nm. Figure 1 As shown.

[0055] To further investigate the AIE performance of the probe, ethanol and water were used as the solvent system, and the fluorescence spectra of the probe (concentration of 10 μM) at different volume fractions of water were measured. Figure 2 As shown, the probe emits weak fluorescence in ethanol solution. With increasing water content to 60%, the fluorescence emission peak red-shifts to 510 nm and gradually intensifies, emitting green fluorescence. When the water content is ≥70%, a new emission peak appears at 605 nm, and orange-red fluorescence is observed. This indicates that the compound possesses significant AIE characteristics.

[0056] Test Example 2

[0057] The near-infrared fluorescent probe TPMC synthesized in Example 1 was dissolved in EtOH to prepare a probe concentration of 1×10⁻⁶. - 5 The fluorescence selectivity of EtOH / H2O (1 / 9, v / v, pH = 7.4) to different antibiotics was determined. Figure 3 This is a fluorescence selectivity spectrum.

[0058] from Figure 3 As can be seen, the probe itself, when excited at a wavelength of 400 nm, emits a strong orange-red fluorescence at a maximum emission wavelength of 610 nm. After adding different antibiotics, the changes in its fluorescence spectrum were detected using a fluorescence spectrophotometer, and the results are as follows: Figure 3As shown, the fluorescence emission peak at 610 nm weakened and the fluorescence emission peak at 505 nm strengthened after the addition of erythromycin, and the fluorescence of the solution changed from orange-red to green. The addition of other antibiotics, including amoxicillin, fluconazole, sulfadiazine, metronidazole, penicillin G sodium, tetracycline, and cefalexin, did not cause any significant changes in the fluorescence spectrum, achieving highly selective detection of erythromycin.

[0059] Test Example 3

[0060] Different concentrations of erythromycin (0-50 μM) were added to EtOH / H2O (3 / 2, v / v, pH = 7.4) solutions containing 10 μM TPMC, and the changes in their fluorescence spectra were detected. Figure 4 As shown, with increasing erythromycin concentration, the fluorescence at 605 nm gradually decreases, while the fluorescence at 510 nm gradually increases. The ratio of erythromycin concentration (0-50 μM) to fluorescence intensity (F...) is also shown. 605 / F 510 ) exhibits a good linear relationship (see Figure 5 This study achieved ratio detection of erythromycin, with a detection limit of 9.80 × 10⁻⁶. - 8 M.

[0061] Figure 4 The illustration shows the fluorescence color change (from orange-red to yellow to yellow-green to green) under a 365nm UV lamp as different concentrations of erythromycin are gradually added to the probe TPMC solution, realizing the visual qualitative detection of erythromycin.

[0062] Test Example 4

[0063] To further determine the effect of the presence of other antibiotics on the detection of erythromycin, a competitive fluorescence experiment was performed. 50 μM erythromycin was added to an EtOH / H₂O (3 / 2, v / v, pH = 7.4) solution containing 10 μM TPMC, followed by equal volumes of other antibiotics. The ratio of fluorescence intensity at 605 nm and 510 nm was then measured. Figure 6 It is evident that the presence of the aforementioned coexisting antibiotics did not significantly alter the detection efficacy of the TPMC probe for erythromycin.

[0064] Fluorescence spectroscopy analysis showed that the TPMC probe could still detect erythromycin in the presence of other antibiotics.

[0065] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A near-infrared fluorescent probe for recognizing erythromycin, characterized in that, The structural formula of the fluorescent probe is as follows: 。 2. A method for preparing a near-infrared fluorescent probe according to claim 1, characterized in that, The method includes reacting ethyl 2-(3-aldehyde-4-hydroxyphenyl)-4-methylthiazol-5-carboxylate with 6-amino-3,4-dihydro-1(2H)-naphthone to obtain the near-infrared fluorescent probe.

3. The method according to claim 2, wherein, The method includes the following steps: (1) 2-(3-aldehyde-4-hydroxyphenyl)-4-methylthiazol-5-carboxylic acid ethyl ester, 6-amino-3,4-dihydro-1(2H)-naphthone and catalyst were dissolved in an organic solvent to obtain a mixed solution; (2) Heat the mixed solution obtained in step (1) under reflux to react; (3) After the reaction is complete, cool to room temperature and a red precipitate will be formed. After filtration, washing and drying, the near-infrared fluorescent probe is obtained.

4. The method according to claim 3, wherein, In step (1), the molar ratio of ethyl 2-(3-aldehyde-4-hydroxyphenyl)-4-methylthiazol-5-carboxylate to 6-amino-3,4-dihydro-1(2H)-naphthone is 1:

1. And / or, the catalyst is glacial acetic acid; And / or, the organic solvent is ethanol.

5. The method according to claim 3 or 4, wherein, The heating temperature in step (2) is 80-90 ℃; And / or, the reaction time is 5-6 h.

6. The method according to claim 3 or 4, wherein, In step (3), the reaction is monitored using a TLC plate; And / or, the washing is washing with ethanol 2-3 times.

7. The application of the near-infrared fluorescent probe according to claim 1 or the near-infrared fluorescent probe prepared by any one of claims 2-6 in the detection of erythromycin.

8. The application according to claim 7, wherein, The near-infrared fluorescent probe is used for sensing and detecting the content of erythromycin in aquatic environments.

9. The application according to claim 8, wherein, The sensing detection is either colorimetric fluorescence detection or visual qualitative detection.

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