Preparation method and application of AIE-banana starch compound

Abstract

The invention provides a preparation method and application of an AIE-banana starch composition.The preparation method comprises the steps that banana starch is subjected to pretreatment such as citric acid soaking and double-enzyme enzymolysis, then the banana starch is dissolved in dimethyl sulfoxide to prepare a 5-10 g / L solution, and an AIE material is prepared into a 0.2-2 g / L solution; shearing 1-2ml of starch solution at a high speed of 6000-8000 revolutions per minute for 30-60 minutes, mixing the starch solution with the same volume of AIE solution, continuously shearing for 25-40 minutes, and inhibiting oxidation through nitrogen protection; and extracting with 5-20 times of distilled water at 50-60 DEG C, centrifuging at 8000-12000 r / min, and drying at 40-60 DEG C to obtain the compound. According to the method, starch hydroxyl and AIE molecules are promoted to be combined through hydrogen bonds and Van der Waals force by utilizing high-speed shearing force, non-radiative transition of the AIE molecules is blocked, and fluorescence emission is enhanced. The prepared compound can be used as a fluorescent tracer for distribution tracking of nutrients, medicines and the like in organisms.

Description

Technical Field

[0001] The present invention relates to the technical field of fluorescent functional material preparation, and in particular to a preparation method and application of an AIE-banana starch complex. Background Art

[0002] Aggregation-induced emission (AIE) materials, in their dispersed state, dissipate excited-state energy through non-radiative transitions due to intramolecular motion (e.g., rotation and vibration), manifesting as fluorescence quenching. However, when their molecular motion is restricted, such as by aggregation or rigid environmental constraints, radiative transition channels open up, resulting in significant fluorescence enhancement, and possessing potential for application in biological tracing. Starch, with its unique helical cavity structure and abundant hydroxyl groups, can bind to AIE molecules through hydrogen bonds and other interactions, restricting their motion, making it considered an ideal confining carrier for AIE molecules. However, in the existing technology, AIE materials and starch have low reactivity and poor compatibility in the same medium. Conventional physical mixing or chemical modification methods have problems such as low compounding efficiency and complex processes, which make it difficult to effectively promote the interaction between AIE molecules and starch, resulting in insufficient fluorescence enhancement effect. Summary of the Invention

[0003] In view of this, the present invention proposes a preparation method and application of an AIE-banana starch complex to solve the above problems.

[0004] The technical solution of the present invention is achieved as follows: a method for preparing an AIE-banana starch complex comprises the following steps: (1) Solution preparation: Dissolve banana starch in dimethyl sulfoxide (DMSO) solution to prepare a banana starch solution with a concentration of 5-10 g / L; dissolve the AIE material in dimethyl sulfoxide (DMSO) solution to prepare an AIE solution with a concentration of 0.2-2 g / L; (2) Starch pre-shearing: 1-2 ml of the banana starch solution prepared in step (1) was placed in a quartz tube (volume ≥ 50 ml) and subjected to high-speed shearing for 30-60 minutes; (3) Mixing reaction: adding the AIE solution prepared in step (1) to the quartz tube treated in step (2), and continuing the high-speed shear treatment at a speed of 6000-8000 rpm for 25-40 minutes to carry out the mixing reaction; (4) Extraction and purification: The mixed solution obtained in step (3) is transferred to a container and extracted with distilled water to precipitate the banana starch complex and remove unreacted AIE material; (5) Separation and drying: The mixture obtained in step (4) is centrifuged, the supernatant is discarded, and the precipitate is collected and dried to obtain the AIE-banana starch complex.

[0005] Furthermore, the banana starch processing steps in step (1) are as follows: peeling and slicing fresh bananas, soaking them in a citric acid solution with a mass concentration of 0.05%-0.15% for 5-10 minutes, and then beating them into juice together with the citric acid solution; adjusting the pH of the juice to 3-5, adding 0.1%-0.3% pectinase by weight of the juice, and performing enzymolysis in a water bath at 40-50°C for 2-4 hours, then adjusting the pH to 4-6, adding 0.05%-0.1% cellulase by weight of the juice, and performing enzymolysis in a water bath at 45-55°C for 1-2 hours, centrifuging, discarding the upper layer liquid, adding water, continuing centrifugation, and taking the lower layer liquid; adding HCl solution to the lower layer liquid, stirring for 3-5 minutes, and reacting in a water bath at 40-50°C for 1-2 hours, centrifuging, discarding the upper layer liquid, and adding water to the precipitate and continuing centrifugation, repeating the addition of water and centrifugation 3-5 times, and taking the precipitate and drying.

[0006] Furthermore, the AIE material in step (1) is a water-soluble porphyrin derivative.

[0007] The synthesis method of the water-soluble porphyrin derivative includes the steps of preparing compound 1 and compound 2: Preparation of compound 1: In a 100 mL round-bottom flask equipped with a reflux condenser and a magnetic stirrer, 3.02 g (0.02 mol) of methyl p-aminobenzoate, 0.02 mol of an aldehyde compound, and 0.34 g (0.002 mol) of p-toluenesulfonic acid were added and dissolved with 50 mL of glacial acetic acid. After stirring the mixture at 90°C for 30 minutes, 0.86 g (0.01 mol) of 2,3-butanedione was slowly added, and the mixture was stirred at 90°C for 3 hours. After the reaction, the generated dye precipitate was separated by filtration and washed with glacial acetic acid. The crude product was purified by recrystallization from a mixed solvent of chloroform and ethyl acetate and dried in vacuo to obtain compound 1 as a light yellow powder.

[0008] The synthetic route is as follows:

[0009] Preparation of compound 2: In a 100 mL round-bottom flask equipped with a reflux condenser and a magnetic stirrer, 0.001 mol of compound 1 and 50 mL of tetrahydrofuran (THF) were added and heated to reflux to dissolve compound 1; 2.00 g of sodium hydroxide was dissolved in 8 mL of methanol and slowly added dropwise to the reaction solution (the reaction solution became turbid and insoluble matter precipitated during the addition), and the reaction solution became clear after continued heating and reflux for 8 hours. Heating and stirring were continued for another 12 hours; after the solvent was removed by rotary evaporation, 15 mL of water and 2.00 g of sodium hydroxide were added, and the mixture was heated and stirred for 24 hours; the reaction solution was added dropwise to THF to precipitate the product, and the precipitate was collected by filtration under reduced pressure; the crude product was dissolved in 20 mL of water and added dropwise to THF, and the operation was repeated until the pH of the filtrate was close to neutral. The powder of compound 2, which is the AIE material, was obtained by vacuum drying.

[0010] The synthetic route is as follows:

[0011] Furthermore, the volume ratio of the banana starch solution to the AIE solution in step (3) is 1:1-2.

[0012] Furthermore, the high-speed shearing process in step (3) is carried out under a nitrogen protective atmosphere.

[0013] Furthermore, the high-speed shearing speed in steps (3) and (4) is 6000-8000 rpm.

[0014] Furthermore, in the extraction and separation step of step (4), the volume of distilled water added is 5-20 times the volume of the mixed solution.

[0015] Furthermore, the extraction in step (4) is carried out at a constant temperature of 50-60° C. and a rotation speed of 150-200 rpm for 3-5 hours.

[0016] Furthermore, the centrifugal separation in step (5) is performed at a speed of 8000-12000 rpm and a centrifugal time of 10-20 minutes; and the drying is performed at 40-60°C.

[0017] Furthermore, the prepared AIE-banana starch complex is used as a fluorescent tracer, and the fluorescent tracer is used for tracing nutrients, active ingredients or drugs.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses natural banana starch and water-soluble AIE materials to prepare high-performance composites through a green process. The raw materials are extracted by biological enzymatic hydrolysis, which is safe, environmentally friendly and has excellent biocompatibility. The preparation process uses a two-stage high-speed shear process to achieve efficient molecular-level composite under mild conditions, significantly improving the loading efficiency and fluorescence performance. The resulting composite has stable aggregation-induced luminescence characteristics and can be used as a precise tracer for tracking nutrient or drug metabolism in organisms. Its positioning accuracy exceeds that of traditional methods. This technology breaks through the bottleneck of compatibility between starch carriers and fluorescent materials, and achieves a synergistic improvement in fluorescence intensity and stability with a simple and controllable process, providing an innovative solution for biomedical testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the infrared spectrum of the composite material of Example 3 and banana starch. DETAILED DESCRIPTION

[0020] In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0021] Unless otherwise specified, the experimental methods used in the examples of the present invention are all conventional methods.

[0022] Unless otherwise specified, the materials, reagents, etc. used in the examples of the present invention can be obtained from commercial sources.

[0023] The vortex fluidic device (VFD) used in the embodiments of the present invention is a controllable microfluidic device. Its main structure is a rotating glass tube with an adjustable tilt angle (45°). It generates a thin film liquid layer and shear force through high-speed rotation, forming a stable vortex fluid dynamic environment.

[0024] Example 1 Preparation of an AIE-banana starch complex (1) Solution preparation: Dissolve banana starch in dimethyl sulfoxide solution to prepare a banana starch solution with a concentration of 5 g / L; dissolve the water-soluble porphyrin derivative in dimethyl sulfoxide solution to prepare an AIE solution with a concentration of 0.2 g / L.

[0025] (2) Starch pre-shearing: 1 mL of the banana starch solution prepared in step (1) was placed in a 5 mL quartz tube, which was fixed to a VFD device and subjected to high-speed shearing treatment at a speed of 6000 rpm for 60 min.

[0026] (3) Mixing reaction: 1 ml of the AIE solution prepared in step 1 was added to the quartz tube treated in step (2), and the high-speed shear treatment was continued at 6000 rpm for 40 minutes to perform the mixing reaction.

[0027] (4) Extraction and purification: The mixed solution obtained in step (3) was transferred to a container, and distilled water 5 times the volume of the mixed solution was added. The mixture was extracted at a constant temperature of 50°C and a rotation speed of 150 rpm for 5 hours to precipitate the banana starch complex and remove the unreacted AIE material.

[0028] (5) Separation and drying: The mixture obtained in step (4) was centrifuged at 8000 rpm for 20 minutes, the supernatant was discarded, and the precipitate was collected and dried at 40° C. to obtain the AIE-banana starch complex.

[0029] Example 2 Preparation of an AIE-banana starch complex (1) Solution preparation: Dissolve banana starch in dimethyl sulfoxide solution to prepare a banana starch solution with a concentration of 10 g / L; dissolve water-soluble porphyrin derivative in dimethyl sulfoxide solution to prepare an AIE solution with a concentration of 2 g / L.

[0030] (2) Starch pre-shearing: 2 ml of the banana starch solution prepared in step (1) was placed in a 5 mL quartz tube, which was fixed to a VFD device and subjected to high-speed shearing treatment at a speed of 8000 rpm for 30 min.

[0031] (3) Mixing reaction: 2 ml of the AIE solution prepared in step 1 was added to the quartz tube treated in step (2), and the high-speed shear treatment was continued at 8000 rpm for 25 minutes to carry out the mixing reaction. This process was carried out under a nitrogen atmosphere.

[0032] (4) Extraction and purification: The mixed solution obtained in step (3) was transferred to a container, and distilled water (20 times the volume of the mixed solution) was added. The mixture was extracted at a constant temperature of 60°C and a rotation speed of 200 rpm for 3 hours to precipitate the banana starch complex and remove the unreacted AIE material.

[0033] (5) Separation and drying: The mixture obtained in step (4) was centrifuged at a speed of 12000 rpm for 10 minutes, the supernatant was discarded, and the precipitate was collected and dried at 60°C to obtain the AIE-banana starch complex.

[0034] Example 3 Preparation of an AIE-banana starch complex (1) Solution preparation: Dissolve banana starch in dimethyl sulfoxide solution to prepare a banana starch solution with a concentration of 7.5 g / L; dissolve the water-soluble porphyrin derivative in dimethyl sulfoxide solution to prepare an AIE solution with a concentration of 1 g / L.

[0035] (2) Starch pre-shearing: 1.5 ml of the banana starch solution prepared in step (1) was placed in a 5 ml quartz tube, which was fixed to a VFD device and subjected to high-speed shearing treatment at a speed of 7000 rpm for 45 minutes.

[0036] (3) Mixing reaction: 1.5 ml of the AIE solution prepared in step 1 was added to the quartz tube treated in step (2), and the high-speed shear treatment was continued at 7000 rpm for 30 minutes to carry out the mixing reaction. This process was carried out under a nitrogen atmosphere.

[0037] (4) Extraction and purification: The mixed solution obtained in step (3) was transferred to a container, and distilled water (10 times the volume of the mixed solution) was added. The mixture was extracted at a constant temperature of 55°C and a rotation speed of 180 rpm for 4 hours to precipitate the banana starch complex and remove the unreacted AIE material.

[0038] (5) Separation and drying: The mixture obtained in step (4) was centrifuged at a speed of 10,000 rpm for 15 minutes, the supernatant was discarded, and the precipitate was collected and dried at 50° C. to obtain the AIE-banana starch complex.

[0039] Comparative Example 1 Preparation of AIE-banana starch composite without starch pre-shearing treatment (1) Solution preparation: Dissolve banana starch in dimethyl sulfoxide solution to prepare a banana starch solution with a concentration of 5 g / L; dissolve the AIE material in dimethyl sulfoxide solution to prepare an AIE solution with a concentration of 0.2 g / L.

[0040] (2) Mixing reaction: 1 ml of the banana starch solution prepared in step (1) was placed in a 5 ml quartz tube. The quartz tube was fixed to a VFD device, and 1 ml of the AIE solution prepared in step 1 was directly added. The mixture was subjected to high-speed shear treatment at a speed of 6000 rpm for 40 minutes for mixing reaction.

[0041] (3) Extraction and purification: The mixed solution obtained in step (2) was transferred to a container, and distilled water 5 times the volume of the mixed solution was added. The mixture was extracted at a constant temperature of 50°C and a rotation speed of 150 rpm for 5 hours to precipitate the banana starch complex and remove the unreacted AIE material.

[0042] (4) Separation and drying: The mixture obtained in step (3) was centrifuged at 8000 rpm for 20 minutes, the supernatant was discarded, and the precipitate was collected and dried at 40° C. to obtain the AIE-banana starch complex.

[0043] Comparative Example 2 Preparation of AIE-banana starch composites at high shear speed (1) Solution preparation: Dissolve banana starch in dimethyl sulfoxide solution to prepare a banana starch solution with a concentration of 5 g / L; dissolve the water-soluble porphyrin derivative in dimethyl sulfoxide solution to prepare an AIE solution with a concentration of 0.2 g / L.

[0044] (2) Starch pre-shearing: 1 ml of the banana starch solution prepared in step 1 was placed in a 5 ml quartz tube, which was fixed to a VFD device and subjected to high-speed shearing treatment at a speed of 3000 rpm for 60 min.

[0045] (3) Mixing reaction: 1 ml of the AIE solution prepared in step 1 was added to the quartz tube treated in step (2), and the high-speed shear treatment was continued at 3000 rpm for 40 minutes to perform the mixing reaction.

[0046] (4) Extraction and purification: The mixed solution obtained in step (3) was transferred to a container, and distilled water 5 times the volume of the mixed solution was added. The mixture was extracted at a constant temperature of 50°C and a rotation speed of 150 rpm for 5 hours to precipitate the banana starch complex and remove the unreacted AIE material.

[0047] (5) Separation and drying: The mixture obtained in step (4) was centrifuged at 8000 rpm for 20 minutes, the supernatant was discarded, and the precipitate was collected and dried at 40° C. to obtain the AIE-banana starch complex.

[0048] Comparative Example 3 Preparation of AIE-banana starch composite without mixing reaction under nitrogen atmosphere (1) Solution preparation: Dissolve banana starch in dimethyl sulfoxide solution to prepare a banana starch solution with a concentration of 5 g / L; dissolve the water-soluble porphyrin derivative in dimethyl sulfoxide solution to prepare an AIE solution with a concentration of 0.2 g / L.

[0049] (2) Starch pre-shearing: 1 ml of the banana starch solution prepared in step (1) was placed in a 5 ml quartz tube, which was fixed to a VFD device and subjected to high-speed shearing treatment at a speed of 6000 rpm for 60 minutes.

[0050] (3) Mixing reaction: 1 ml of the AIE solution prepared in step 1 was added to the quartz tube treated in step (2), and the high-speed shear treatment was continued at 6000 rpm for 40 minutes to perform the mixing reaction. This process was not carried out under a nitrogen atmosphere.

[0051] (4) Extraction and purification: The mixed solution obtained in step (3) was transferred to a container, and distilled water 5 times the volume of the mixed solution was added. The mixture was extracted at a constant temperature of 50°C and a rotation speed of 150 rpm for 5 hours to precipitate the banana starch complex and remove the unreacted AIE material.

[0052] (5) Separation and drying: The mixture obtained in step (4) was centrifuged at 8000 rpm for 20 minutes, the supernatant was discarded, and the precipitate was collected and dried at 40° C. to obtain the AIE-banana starch complex.

[0053] Test Example 1: Fluorescence Performance Test A fluorescence spectrometer (model: Hitachi F-7000) was used to measure the fluorescence intensity of the sample in DMF solution (the concentration was uniformly adjusted to 0.1 mg / mL) at an excitation wavelength of 365 nm and scanning the emission spectrum range of 400-700 nm.

[0054] Test results:

[0055] In Comparative Example 1, where starch pre-shearing was not performed, the fluorescence intensity was only 66.1% of that in Example 3, indicating that pre-shearing promotes stretching of starch molecular chains, increases contact area with the AIE material, and improves composite efficiency. In Comparative Example 2, the fluorescence intensity decreased significantly when the rotational speed was reduced to 3000 rpm, indicating that the shear force generated by high-speed shearing (6000-8000 rpm) is a key factor in promoting molecular collisions. In Comparative Example 3, where nitrogen protection was not used, the fluorescence intensity decreased by 31.3%, likely due to quenching of the luminescent group caused by oxidation of the AIE material in air.

[0056] The composite material of Example 3 and pure banana starch were subjected to infrared spectroscopy test. Scanning range: 4000-500cm -1 Place the prepared sample in the light path and collect the infrared spectrum.

[0057] The results are as follows Figure 1 As shown: 3285cm -1 : Hydroxyl (-OH), the stretching vibration of hydroxyl in AIE-BS complex is enhanced, there are a large number of associated hydroxyl groups in the complex, AIE combines with banana starch to cause spatial displacement, and the intramolecular hydrogen bonds and intermolecular hydrogen bonds are enhanced.

[0058] 1633cm -1 : Aromatic compounds, the newly generated aromatic peaks of AIE-BS indicate that the introduction of AIE has chemically reacted with banana starch.

[0059] 987cm -1 : RO stretching vibration is enhanced, and the alkyl group in the AIE molecule undergoes a substitution reaction with the hydroxyl group on the starch molecular chain.

[0060] The infrared spectroscopy results directly proved the non-physical mixing composite mechanism between AIE and banana starch, providing a structural basis for the enhanced fluorescence properties of the composite. The covalent bond and hydrogen bond inhibited the aggregation-induced quenching (ACQ) effect of AIE molecules, enabling it to maintain excellent luminescence properties in the composite state.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing an AIE-banana starch complex, characterized in that: The following steps are involved: (1) Solution preparation: banana starch was dissolved in dimethyl sulfoxide solution to prepare a banana starch solution with a concentration of 5-10 g / L; AIE material was dissolved in dimethyl sulfoxide solution to prepare an AIE solution with a concentration of 0.2-2 g / L; (2) Starch pre-shearing: 1-2 ml of the banana starch solution prepared in step (1) was placed in a quartz tube and subjected to high-speed shearing for 30-60 minutes; (3) Mixing reaction: adding the AIE solution prepared in step (1) to the quartz tube treated in step (2), and continuing the high-speed shear treatment at a speed of 6000-8000 rpm for 25-40 minutes to carry out the mixing reaction; (4) Extraction and purification: The mixed solution obtained in step (3) is transferred to a container and extracted with distilled water to precipitate the banana starch complex and remove unreacted AIE material; (5) Separation and drying: The mixture obtained in step (4) is centrifuged, the supernatant is discarded, and the precipitate is collected and dried to obtain the AIE-banana starch complex.

2. The method for preparing an AIE-banana starch complex according to claim 1, wherein: The banana starch processing steps of step (1) are as follows: peeling and slicing fresh bananas, soaking them in a citric acid solution with a mass concentration of 0.05%-0.15% for 5-10 minutes, and beating them together with the citric acid solution into juice; adjusting the pH of the juice to 3-5, adding 0.1%-0.3% pectinase by weight of the juice, and enzymolyzing them in a water bath at 40-50°C for 2-4 hours, then adjusting the pH to 4-6, adding 0.05%-0.1% cellulase by weight of the juice, and enzymolyzing them in a water bath at 45-55°C for 1-2 hours, centrifuging, discarding the upper layer liquid, adding water, continuing centrifugation, and taking the lower layer liquid; adding HCl solution to the lower layer liquid, stirring for 3-5 minutes, and reacting in a water bath at 40-50°C for 1-2 hours, centrifuging, discarding the upper layer liquid, and adding water to the precipitate and continuing centrifugation, repeating the addition of water and centrifugation 3-5 times, and taking the precipitate and drying it.

3. The method for preparing an AIE-banana starch complex according to claim 1, wherein: The AIE material in step (1) is a water-soluble porphyrin derivative.

4. The method for preparing an AIE-banana starch complex according to claim 1, wherein: The volume ratio of the banana starch solution to the AIE solution in step (3) is 1:1-2.

5. The method for preparing an AIE-banana starch complex according to claim 1, wherein: The high-speed shearing in step (3) is carried out under a nitrogen protective atmosphere.

6. The method for preparing an AIE-banana starch complex according to claim 1, wherein: The high-speed shearing speed in steps (3) and (4) is 6000-8000 rpm.

7. The method for preparing an AIE-banana starch complex according to claim 1, wherein: In the extraction and purification in step (4), the volume of distilled water added is 5-20 times the volume of the mixed solution.

8. The method for preparing an AIE-banana starch complex according to claim 1, wherein: The extraction in step (4) is carried out at a constant temperature of 50-60°C and a rotation speed of 150-200 rpm for 3-5 hours.

9. The method for preparing an AIE-banana starch complex according to claim 1, wherein: The centrifugal separation in step (5) is carried out at a speed of 8000-12000 rpm and a centrifugal time of 10-20 minutes; the drying is carried out at a temperature of 40-60°C.

10. Use of the AIE-banana starch complex prepared according to the preparation method of the AIE-banana starch complex according to any one of claims 1 to 9 as a fluorescent tracer for tracing nutrients, active ingredients or drugs.

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