Preparation Method and Application of a Mesoporous Silicon-Based Aggregation-Induced Emission Material

Abstract

The present invention provides a preparation method and application of a mesoporous silica-based aggregation-induced emission material. By loading AIE molecules on the prepared dendritic mesoporous silica (DMSN), a mesoporous silica-based aggregation-induced emission material is obtained. The rich nanoporous structure of DMSN is used to precisely regulate the quantity, state, etc. of the adsorbed and immobilized AIE molecules, and high-brightness and stable fluorescence signals of different colors and different brightnesses can be obtained. The technical solution of the present invention overcomes the problems of poor fluorescence stability and water solubility of traditional fluorescent dyes, and solves the existing technical problems such as low water solubility and uncontrollable aggregation of aggregation-induced emission materials.

Description

Technical Field

[0001] The present invention relates to the field of materials, and specifically, to a general synthesis method and application examples of mesoporous silica-based aggregation-induced emission materials. Background Art

[0002] Fluorescence is the light emitted when a fluorescent molecule returns to the ground state through radiative transition from the first excited singlet state after being photoexcited. As the output data of an optical detection system, fluorescence signals are widely used in the fields of detection, in vitro and in vivo imaging, etc. due to their non-destructive, highly sensitive, specific, and real-time monitoring characteristics. However, for most conventional organic fluorescent molecules (such as FITC), due to the existence of π-π stacking between molecules, they face aggregation and exhibit aggregation-caused quenching (ACQ) phenomenon in high concentration or solid state, resulting in fluorescence quenching. They usually can only be used at very dilute concentrations and are easily photo-bleached, with unstable fluorescence properties.

[0003] In 2001, the research group of Ben Zhong Tang found that silole derivatives (HPS) have a phenomenon completely opposite to ACQ. These materials show negligible fluorescence in dilute solutions, and with the aggregation of molecules, the fluorescence is significantly enhanced. Based on this phenomenon, the concept of aggregation-induced emission (AIE) was proposed. AIE molecules have successfully overcome the limitations of the ACQ effect of traditional fluorescent dyes in the application process, greatly improving the photostability and intensity, and having obvious advantages in the fields of in vitro detection, tumor imaging, and long-term tracing, etc. However, AIE molecules still have some deficiencies when facing practical applications: their water solubility and photostability in complex environments need to be improved; there is a lack of a universal construction strategy for aggregation-induced emission molecules to meet different needs; the aggregation controllability is poor, and it is difficult to achieve precise regulation of luminescence performance, etc.

[0004] Currently, the materials reported for loading AIE include metal-organic framework materials, hydrogels, etc., which still cannot achieve precise regulation of the physical or fluorescence properties of AIE materials. At the same time, the interaction force is weak, AIE molecules are prone to leakage, and the fluorescence stability is poor. Summary of the Invention

[0005] Aiming at the problems in the prior art, the purpose of the present invention is to provide a preparation method and application of a mesoporous silica-based aggregation-induced emission material with good stability and water solubility, which can achieve controllable aggregation.

[0006] On the one hand, the present invention provides a preparation method of a mesoporous silica-based aggregation-induced emission material, including the following steps:

[0007] Step 1, prepare dendritic mesoporous silica;

[0008] Step 2, load AIE molecules on the dendritic mesoporous silica to obtain a mesoporous silica-based aggregation-induced emission material.

[0009] Preferably, after the dendritic mesoporous silica is prepared in step 1, the surface of the dendritic mesoporous silica is further modified.

[0010] Preferably, the surface modification of the dendritic mesoporous silica in step 1 includes hydrophobic modification or amination modification.

[0011] Preferably, the dendritic mesoporous silica is prepared by a sol-gel method in step 1.

[0012] Preferably, the reagent used for hydrophobic modification in step 1 is a silane coupling agent or a diacid with C8-C18, and the volume ratio of the silane coupling agent or diacid with C8-C18 to tetraethyl orthosilicate is 1:8 - 1:24.

[0013] Preferably, the AIE molecule in step 2 has a positive charge and a hydrophobic end or has a covalent grafting group.

[0014] Preferably, the AIE molecule in step 2 is:

[0015]

[0016] Preferably, in step 2, the dendritic mesoporous silica is dispersed in dimethyl sulfoxide, and a dimethyl sulfoxide solution of the AIE molecule is added and stirred to obtain a mesoporous silica-based aggregation-induced emission material.

[0017] Preferably, the mass ratio of the AIE molecule to the dendritic mesoporous silica in step 2 is 1:200 - 6:200, the stirring temperature is 25 - 80 °C, and the stirring time is 4 - 24 h.

[0018] On the other hand, the present invention provides an application of the mesoporous silica-based aggregation-induced emission material obtained by the preparation method of the mesoporous silica-based aggregation-induced emission material according to the above in ion detection, in vitro detection of biomarkers, or fluorescence imaging.

[0019] A preparation method of a mesoporous silica-based aggregation-induced emission material and a composite-phase fluorescent ceramic according to the technical solution of the present invention has the following beneficial effects:

[0020] 1. The present invention proposes a preparation method for controllably adjusting a silica-based aggregation-induced emission material at the nanoscale, provides a general construction strategy for aggregation-induced emission molecules, and can realize the change of fluorescence color and intensity without changing the type of AIE molecule, achieving precise regulation of luminescence performance.

[0021] 2. The silica-based aggregation-induced emission material obtained by the present invention has a uniform morphology, good water dispersibility, a large specific surface area, high fluorescence stability, and high luminescence intensity.

[0022] 3. This preparation method can obtain a bright and stable fluorescence signal, showing good application potential in the fields of detection or fluorescence imaging. Brief Description of the Drawings

[0023] Other features, objectives, and advantages of the present invention will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings.

[0024] Figure 1a TEM image of the silicon-based AIE material DMSN obtained in Example 1;

[0025] Figure 1b Size distribution diagram of the silicon-based AIE material DMSN obtained in Example 1;

[0026] Figure 2 Water contact angle diagrams of the silicon-based AIE materials obtained in Example 1, Example 2, Example 3, and Example 4, where a - f are the water contact angle diagrams of DMSN, DNC, SMSN-1, SMSN-2, SMSN-3, and pSMSN respectively;

[0027] Figure 3 Fluorescent digital photo diagrams of the silicon-based AIE material DNCA with different mass ratios obtained in Example 2;

[0028] Figure 4 Fluorescence spectra diagrams of the silicon-based AIE material dispersed in water and ethanol (excitation light is 498 nm) obtained in Example 3, where SMA refers to SMA-1 (in the inset photos, 1 and 3, 2 and 4 are the digital photos of SMA-1 dispersed in water and ethanol under daylight and ultraviolet light respectively);

[0029] Figure 5a Fluorescence spectra diagrams of the silicon-based AIE materials obtained in Example 1, Example 2, and Example 3 (excitation light is 498 nm), where SMA refers to SMA-1;

[0030] Figure 5b Fluorescent digital photo diagrams of the silicon-based AIE materials obtained in Example 1, Example 2, and Example 3, where 1 is DMSN, 2 is DA, 3 is DNCA, and 4 is SMA-1;

[0031] Figure 6a Fluorescence spectra diagrams of the silicon-based AIE materials obtained in Example 3 and Example 4 (excitation light is 498 nm);

[0032] Figure 6b Fluorescent digital photo diagrams of the silicon-based AIE materials obtained in Example 3 and Example 4, where 1 is SMA-1, 2 is SMA-2, 3 is SMA-3, and 4 is pSMA;

[0033] Figure 7a Fluorescence spectra of the silicon-based AIE materials obtained in Example 1, Example 5, and Example 6, where DNB-2 refers to DNB-2 (reacted at 80 °C for 4 h);

[0034] Figure 7b Fluorescence spectra of the silicon-based AIE materials obtained in Example 6 at different temperatures;

[0035] Figure 7c Fluorescence intensity graphs of the silicon-based AIE materials obtained in Example 6 at different reaction times (fluorescence intensity at 509 nm with an excitation light of 350 nm);

[0036] Figure 8a Fluorescence spectra of the silicon-based AIE material (referring to SMA-1) obtained in Example 3 (excitation light at 498 nm) before and after 24 h of sunlight irradiation;

[0037] Figure 8b Fluorescence spectra of the silicon-based AIE material (referring to DNB-2 obtained by reacting at 80 °C for 4 h) obtained in Example 6 (excitation light at 350 nm) before and after 24 h of sunlight irradiation;

[0038] Figure 8c Fluorescence spectra of the silicon-based AIE material obtained in Comparative Example 1 (excitation light at 488 nm) before and after 24 h of sunlight irradiation;

[0039] Figure 9 For Example 3 (referring to SMA-1) against Cu 2+ Fluorescence intensity response graph (fluorescence intensity at 636 nm). Detailed implementation manners

[0040] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. Like reference numerals in the figures denote the same or similar structures, and thus their repetitive description will be omitted.

[0041] In an embodiment of the present invention, a preparation method and application of a mesoporous silicon-based aggregation-induced emission (AIE) material are provided. By performing different surface functionalization modifications on DMSN and utilizing the pore confinement effect of DMSN, a silicon-based AIE material at the nanoscale is constructed to achieve modular integrated design of various AIE molecules.

[0042] Among them, the preparation method of the mesoporous silicon-based aggregation-induced emission material includes the following steps:

[0043] Step 1: First, dendritic mesoporous silica is prepared by the sol-gel method. Then, the dendritic mesoporous silica is surface-modified, preferably by hydrophobic or amination modification. After centrifugation and washing, mesoporous silica with different surface functionalizations is obtained.

[0044] Step 2: The mesoporous silica is dispersed in dimethyl sulfoxide, and a dimethyl sulfoxide solution of the AIE molecule is added and stirred to obtain the mesoporous silica-based aggregation-induced emission material.

[0045] Preferably, in the sol-gel method, cetyltrimethylammonium bromide (CTAB) is used as the surfactant, sodium salicylate (NaSal) is used as the pore-forming agent, triethanolamine (TEA) is used as the base, and tetraethyl orthosilicate (TEOS) is used as the silicon source to prepare dendritic mesoporous silica.

[0046] Preferably, when the dendritic mesoporous silica is subjected to hydrophobic or amination modification, the method is one of the one-step method, grafting method, and post-modification method.

[0047] Preferably, the reagent used for hydrophobic modification is a silane coupling agent or diacid with C8-C18, and the volume ratio to tetraethyl orthosilicate is 1:8 - 1:24.

[0048] Preferably, the AIE molecule has a positive charge and a hydrophobic end or has a covalent grafting group, and the emission color is red, orange, yellow, or green. The specific structural formula is as follows:

[0049]

[0050] More preferably, the red and orange AIE molecules are AIE molecule 1 (i.e., structural formula 1), AIE molecule 2 (i.e., structural formula 2), etc. AIE molecules with a positive charge and a hydrophobic end, and the mesoporous silica is loaded through physical interactions such as electrostatic and hydrophobic interactions. The yellow and green AIE molecules are AIE molecule 3 (i.e., structural formula 3), etc. AIE molecules with a covalent grafting group, and the mesoporous silica is loaded through the substitution reaction of the amino group.

[0051] Furthermore, the mass ratio of the AIE molecule to the mesoporous silica is 1:200 - 6:200, the stirring temperature is 25 - 80 °C, and the stirring time is 4 - 24 h.

[0052] The silicon-based aggregation-induced emission material of the present invention can be used in ion detection, but is not limited to Cu ions, and can also be used in the in vitro detection or fluorescence imaging of biomarkers.

[0053] Dendritic mesoporous silica nanoparticles (DMSN) have characteristics such as a large specific surface area, adjustable particle size / pore size, easy surface modification, and excellent dispersibility and biocompatibility. They are widely used as drug carriers. By physically adsorbing or chemically bonding AIE fluorescent molecules in DMSN and utilizing the pore structure of mesoporous silica, a silicon-based AIE material with controllable particle size and adjustable pore size can be constructed, which is expected to achieve modular integrated design of various AIE molecules, avoid leakage and photobleaching of fluorescent dyes, and obtain a bright and stable fluorescent signal. The obtained material combines the unique properties of AIE molecules and porous materials and has good application prospects in detection and imaging.

[0054] The present invention precisely regulates the quantity, state, etc. of adsorbed and fixed AIE molecules by using the rich nanoporous structure of DMSN, and bright and stable fluorescent signals with different colors and brightness can be obtained. The present invention provides a general synthesis strategy for mesoporous silica-based aggregation-induced emission materials. The obtained materials combine the unique properties of AIE and porous materials and have good application prospects in fields such as detection and imaging.

[0055] The following describes the present invention with specific examples:

[0056] Example 1

[0057] A preparation method for a silicon-based aggregation-induced emission material controllably adjustable at the nanoscale (i.e., the mesoporous silica-based aggregation-induced emission material of the embodiment of the present invention) is as follows:

[0058] Add 760 mg of CTAB (cetyltrimethylammonium bromide) to a three-necked flask, dissolve it in 50 mL of deionized water, place it in an oil bath and heat it to 80 °C, continuously stir at 800 rpm for 30 min, then add 336 mg of NaSal (sodium salicylate) and 121 μL of TEA (triethanolamine), continue stirring for 1 h, and then dropwise add 4 mL of TEOS. After reacting at 80 °C for another 4 h, cool it to room temperature, wash it 3 times each with ethanol and water, and then disperse it in a mixture of 100 mL of ethanol and 9 mL of concentrated hydrochloric acid (37%) and react overnight at 70 °C to remove the template agent CTAB. After that, centrifuge and wash it 3 times each with ethanol and water, and then collect the product DMSN after freeze-drying.

[0059] As can be seen from the Figure 1a appendix, DMSN has a dendritic structure. The results of dynamic light scattering (DLS) show that its hydrodynamic particle size is 234.5 nm, the polydispersity index PDI is 0.034, and the dispersion is uniform (appendix Figure 1b ), the BET specific surface area is 484.1 m 2 / g, and the water contact angle is 30.5°, indicating good hydrophilicity. See appendix Figure 2 a.

[0060] Disperse 20 mg of DMSN in 1.85 mL of DMSO. At room temperature, add 0.15 mL of a 1 mg / mL DMSO solution of AIE molecule 1. After stirring at 300 rpm for 4 h at room temperature, wash it three times with ethanol and water respectively, and disperse it in 2 mL of water for standby, thus obtaining the silicon-based AIE material DA. From the attached Figure 5b digital photo, the color of DA (i.e., 2) changes from white to red. It can be seen from the structural formula of AIE molecule 1 that it carries a positive charge and is loaded by DMSN with a negative surface charge. However, due to the weak hydrophobicity of DMSN, the fluorescence of the obtained DA is not obvious.

[0061] Disperse 20 mg of DMSN in 1.85 mL of DMSO, place it in an oil bath and heat it to 80 °C. Add 0.15 mL of a 1 mg / mL DMSO solution of AIE molecule 3, continue stirring for 4 h, then wash it three times with ethanol and water respectively, and disperse it in 2 mL of water for standby, thus obtaining DB. From the attached Figure 7a inset digital photo, there is almost no color change in DB. Since there is no amino group on unmodified DMSN, DB has no fluorescence.

[0062] Example 2

[0063] A preparation method for controllably adjusting silicon-based aggregation-induced emission materials at the nanoscale is as follows:

[0064] Use the grafting method to prepare hydrophobic dendritic silicon. Add 760 mg of CTAB to a three-necked flask, dissolve it in 50 mL of deionized water, place it in an oil bath and heat it to 80 °C, continuously stir at 800 rpm for 30 min. Then add 336 mg of NaSal and 121 μL of TEA, continue stirring for 1 h, and then dropwise add 4 mL of TEOS. Continue reacting at 80 °C for 4 h, add 200 μL of 3-aminopropyltriethoxysilane (APTES), continue stirring for 2 h, then cool to room temperature, wash it three times with ethanol and water respectively, and disperse it in a mixture of 100 mL of ethanol and 9 mL of concentrated hydrochloric acid (37%) and react overnight at 70 °C to remove the template agent CTAB. After that, centrifuge and wash it three times with ethanol and water respectively, and then collect the product after freeze-drying; dissolve 575 mg of dodecanedioic acid in 90 mL of absolute ethanol, add 317.5 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 80 mg of N-hydroxysuccinimide at 400 rpm, heat it to 40 °C and activate for 2 h. Then, disperse 250 mg of the above product in 10 mL of absolute ethanol and add it to the above solution. Continue stirring for 12 h, centrifuge at 13000 rpm for 10 min, and wash it three times with ethanol and water respectively, and collect the product after freeze-drying. It can be obtained from the attached Figure 2 b that its water contact angle is 43.7°.

[0065] Disperse 20 mg of DNC in a certain amount of DMSO. At room temperature, add DMSO solutions of AIE molecule 1 with a concentration of 1 mg / mL and different volumes (0 μL, 100 μL, 150 μL, 200 μL, 300 μL, 600 μL). Make up the volume of the system to 2 mL. After stirring at 300 rpm for 4 h at room temperature, wash it 3 times with ethanol and water respectively, and disperse it in 2 mL of water for standby, then DNCA is obtained. Due to the modification of the diacid with C12, the hydrophobicity is enhanced, enabling AIE molecule 1 to be confined in the pores of mesoporous silica through hydrophobic and electrostatic interactions, resulting in the obstruction of the non-radiative transition channel after photoexcitation and obvious fluorescence. At the same time, as the addition amount of AIE molecule 1 increases, the fluorescence intensity also increases, as shown in the appendix Figure 3 as follows.

[0066] Example 3

[0067] A preparation method for controllably regulating silicon-based aggregation-induced emission materials at the nanoscale is as follows:

[0068] Prepare hydrophobic dendritic silicon by a one-step method. Add 760 mg of CTAB to a three-necked flask, dissolve it in 50 mL of deionized water, place it in an oil bath and heat it to 80 °C, continuously stir at 800 rpm for 30 min. Then add 336 mg of NaSal and 121 μL of TEA, continue stirring for 1 h, and then dropwise add a mixture of 4 mL of TEOS and 0.17 mL, 0.48 mL of octadecyltrimethoxysilane (ODMS) or 0.17 mL of octyltrimethoxysilane (OTMS) respectively. After continuing the reaction at 80 °C for 4 h, cool it to room temperature. Wash it 3 times with ethanol and water respectively, and disperse it in a mixture of 100 mL of ethanol and 9 mL of concentrated hydrochloric acid (37%) and react overnight at 70 °C to remove the template CTAB. After that, centrifuge it, wash it 3 times with ethanol and water respectively, and collect the products SMSN-1 (prepared from TEOS + 0.17 mL ODMS), SMSN-2 (prepared from TEOS + 0.48 mL ODMS), and SMSN-3 (prepared from TEOS + 0.17 mL OTMS) after freeze-drying. It can be obtained from (c), (d), (e) in the appendix Figure 2 that the water contact angles of the three are 81.2°, 91.33°, and 69.92° in turn, indicating that the hydrophobicity becomes stronger as the length and addition amount of the hydrophobic chain increase.

[0069] Disperse 20 mg of SMSN-1, SMSN-2, and SMSN-3 separately in 1.85 mL of DMSO. At room temperature, add 0.15 mL of a 1 mg / mL DMSO solution of AIE molecule 1. After stirring at 300 rpm for 4 h at room temperature, wash three times with ethanol and water respectively, and disperse in 2 mL of ethanol or water for standby, thus obtaining SMA-1, SMA-2, and SMA-3.

[0070] As can be seen from the appendix Figure 4 that dispersing SMA-1 in different systems will cause changes in its fluorescence properties. There are obvious differences in the fluorescence intensities in the ethanol and water dispersion systems. In addition, the strongest emission light in ethanol is 638 nm, while the strongest emission light in water is 670 nm. This is because the polarities of ethanol and water are different, resulting in changes in the aggregation state of AIE molecule 1. As the polarity decreases, a blue-shift hyperchromic effect occurs in the emission spectrum. However, there is almost no difference in the dispersibility of SMA-1 in water and ethanol. The PDI is 0.094 in water and 0.116 in ethanol, both showing good dispersibility and good fluorescence stability. Before and after 24 h of sunlight irradiation, the fluorescence intensity at the strongest emission light of 636 nm hardly changes, and the fluorescence decay rate is only 0.01%, as shown in the appendix Figure 8a shown.

[0071] Disperse 2 mg of SMA-1 in 2 mL of water, and dropwise add different amounts of a 0.3 mM Cu 2+ solution. After standing at room temperature for 10 min, compare the fluorescence changes of the SMA solution before and after adding copper ions. It is found that this nanosensor shows good fluorescence response properties to Cu 2+ , as shown in the appendix Figure 9 shown.

[0072] Example 4

[0073] A preparation method for controllably adjusting silicon-based aggregation-induced emission materials at the nanoscale is as follows:

[0074] The post-modification method was adopted to prepare hydrophobic dendritic silica. 760 mg of CTAB was added to a three-necked flask, dissolved in 50 mL of deionized water, placed in an oil bath and heated to 80 °C, continuously stirred at 800 rpm for 30 min, then 336 mg of NaSal and 121 μL of TEA were added, and after stirring for another 1 h, 4 mL of TEOS was added dropwise, and the reaction continued at 80 °C for 4 h. After cooling to room temperature, it was washed 3 times with ethanol and water respectively, and then dispersed in a mixture of 100 mL of ethanol and 9 mL of concentrated hydrochloric acid (37%) and reacted overnight at 70 °C to remove the template CTAB. After that, it was centrifuged and washed 3 times with ethanol and water respectively, and then freeze-dried to collect the product; 100 mg of the above product was dispersed in 100 mL of absolute ethanol, heated to 78 °C in an oil bath, and 200 μL of octadecyltrimethoxysilane (ODMS) was added at 850 rpm, and the reaction continued for 12 h. After cooling to room temperature, it was centrifuged at 13000 rpm for 10 min, and washed 3 times with ethanol and water respectively, and then freeze-dried to collect the product, namely pSMSN.

[0075] It can be seen from Figure 2 (f) in the appendix that the water contact angle of pSMSN obtained by the post-modification method is 44.0°, which is less hydrophobic than SMSN obtained by the one-step method, but has better dispersibility.

[0076] 20 mg of pSMSN was dispersed in 1.85 mL of DMSO, and 0.15 mL of a DMSO solution of 1 mg / mL AIE molecule 1 was added at room temperature. After stirring at 300 rpm for 4 h at room temperature, it was washed 3 times with ethanol and water respectively, and dispersed in 2 mL of ethanol for standby, namely pSMA.

[0077] It can be seen from Figure 6a and 6b in the appendix that with the increase of hydrophobicity, the fluorescence intensity changes significantly. Among them, SMA-2 obtained from SMSN-2 with the strongest hydrophobicity has the strongest fluorescence intensity. Combining Figure 5a and 5b in the appendix, it can be concluded that AIE molecule 1 is loaded on dendritic silica through electrostatic interaction and hydrophobic interaction, and the main role is played by hydrophobic interaction. By changing the hydrophobic chain length and dosage, the fluorescence intensity can be regulated under the same AIE dosage.

[0078] Example 5

[0079] A preparation method for controllably regulating silicon-based aggregation-induced emission materials at the nanoscale is as follows:

[0080] The amino-functionalized dendritic silicon was prepared by a one-step method. 760 mg of CTAB was added to a three-necked flask, dissolved in 50 mL of deionized water, and placed in an oil bath and heated to 80 °C. Stirring was continued at 800 rpm for 30 min. Then, 336 mg of NaSal and 121 μL of TEA were added, and stirring was continued for 1 h. Subsequently, 4 mL of TEOS was added dropwise, and the reaction was continued at 80 °C for 4 h. 200 μL of APTES was added, and stirring was continued for 2 h. After cooling to room temperature, it was washed three times with ethanol and water each, and then dispersed in a mixture of 100 mL of ethanol and 9 mL of concentrated hydrochloric acid (37%) and reacted overnight at 70 °C to remove the template CTAB. After that, it was centrifuged and washed three times with ethanol and water each, and then freeze-dried to collect the product DN-1, whose Zeta potential was +31.9 mV.

[0081] 20 mg of DN-1 was dispersed in 1.85 mL of DMSO, placed in an oil bath and heated to 80 °C. 0.15 mL of a DMSO solution of 1 mg / mL AIE molecule 3 was added, and stirring was continued for 4 h. Then, it was washed three times with ethanol and water each, and dispersed in 2 mL of water for standby, obtaining DNB-1, whose Zeta potential was +28.2 mV, indicating that the amino groups on the surface of DN-1 were replaced by bromine on AIE molecule 3, resulting in a slight decrease in the potential. It emitted yellow light under ultraviolet lamp irradiation, as shown in the inset in the appendix. Figure 7a as shown in the inset in the appendix.

[0082] Example 6

[0083] A preparation method for controllably regulating silicon-based aggregation-induced emission materials at the nanoscale is as follows:

[0084] The amino-functionalized dendritic silicon was prepared by a post-modification method. 760 mg of CTAB was added to a three-necked flask, dissolved in 50 mL of deionized water, and placed in an oil bath and heated to 80 °C. Stirring was continued at 800 rpm for 30 min. Then, 336 mg of NaSal and 121 μL of TEA were added, and stirring was continued for 1 h. Subsequently, 4 mL of TEOS was added dropwise, and the reaction was continued at 80 °C for 4 h. After cooling to room temperature, it was washed three times with ethanol and water each, and then dispersed in a mixture of 100 mL of ethanol and 9 mL of concentrated hydrochloric acid (37%) and reacted overnight at 70 °C to remove the template CTAB. After that, it was centrifuged and washed three times with ethanol and water each, and then freeze-dried to collect the product. 100 mg of the above product was dispersed in 100 mL of absolute ethanol, heated to 78 °C in an oil bath, and 200 μL of APTES was added at 850 rpm, and the reaction was continued for 12 h. After cooling to room temperature, it was centrifuged at 13000 rpm for 10 min, and washed three times with ethanol and water each, and then freeze-dried to collect the product, obtaining DN-2.

[0085] Disperse 20 mg of DN-2 in 1.85 mL of DMSO. After heating to 80 °C in an oil bath at room temperature (25 °C) (DNB-25 °C and DNB-80 °C were prepared respectively), add 0.15 mL of a DMSO solution of 1 mg / mL AIE molecule 3. After continuing to stir for 4 h, wash with ethanol and water three times each, and disperse in 2 mL of water for standby. It shows green light under ultraviolet lamp irradiation, as shown in the Figure 7a inset (where DNB-2 refers to DNB-80 °C). As can be seen from the Figure 7b appendix, the fluorescence intensity of the material obtained at room temperature (DNB-25 °C) is weak. When the reaction temperature is 80 °C, it can promote the substitution reaction of hydrogen on the amino group with bromine on AIE molecule 3, so that more AIE molecules 3 are confined in the mesoporous silica pores, and thus the fluorescence intensity of DNB-80 °C is significantly enhanced.

[0086] Disperse 20 mg of DN-2 in 1.85 mL of DMSO, heat to 80 °C in an oil bath, add 0.15 mL of a DMSO solution of 1 mg / mL AIE molecule 3, continue to stir for 4 h, 8 h, 12 h, 16 h, 24 h, then wash with ethanol and water three times each, and disperse in 2 mL of water for standby, namely DNB-2(4 h), DNB-2(8 h), DNB-2(12 h), DNB-2(16 h), DNB-2(24 h). As shown in the Figure 7c appendix, as the reaction time prolongs, the fluorescence intensity of the silicon-based AIE material DNB-2 decreases. DNB-2 with a reaction time of 4 h is irradiated by sunlight for 24 h. Due to the confinement of the mesoporous silica pores and the protection of AIE molecule 3, the fluorescence intensity at its strongest emission wavelength of 509 nm only slightly decreases, and the fluorescence decay rate is 8.33%, showing good photostability, as shown in the Figure 8b appendix.

[0087] Comparative Example 1

[0088] Add 760 mg of CTAB to a three-necked flask, dissolve it in 50 mL of deionized water, heat to 80 °C in an oil bath, continuously stir at 800 rpm for 30 min, then add 336 mg of NaSal and 121 μL of TEA, continue to stir for 1 h, then dropwise add 4 mL of TEOS, continue to react at 80 °C for 4 h, add 200 μL of APTES, continue to stir for 2 h, then cool to room temperature. After cooling to room temperature, wash with ethanol and water three times each, and disperse in a mixture of 100 mL of ethanol and 9 mL of concentrated hydrochloric acid (37%) to react overnight at 70 °C to remove the template CTAB. After that, centrifuge and wash with ethanol and water three times each, and then collect the product by freeze-drying;

[0089] Disperse 60 mg of the above product in 30 mL of ethanol, add 4 mg of FITC at room temperature, stir in the dark for 12 h, wash with ethanol and water until the supernatant is colorless, and then disperse in 6 mL of water for standby.

[0090] As can be seen from the attached Figure 8c It can be seen that under the same conditions, the fluorescence intensity of the fluorescent material obtained by loading the traditional fluorescent dye FITC on mesoporous silica is not high. After 24 h of sunlight irradiation, its fluorescence is significantly weakened, and the anti-photobleaching property is poor, with a fluorescence decay rate of 75.44%. Therefore, the silicon-based AIE material obtained through the pore confinement effect of mesoporous silica has advantages such as high fluorescence intensity and good photostability.

[0091] The technical solution of the present invention designs and regulates key factors such as the type of surface functionalization of mesoporous silica, the type / addition amount of silane coupling agent, the reaction temperature / time between mesoporous silica and AIE molecules at the nanoscale, and obtains silicon-based aggregation-induced emission (AIE) materials with different emission colors and intensities, provides a general construction strategy for aggregation-induced emission molecules, realizes precise regulation of luminescence performance, obtains silicon-based AIE materials with high brightness and stability, and uses this as an ion probe to realize the rapid detection of Cu 2+ and shows good fluorescence response characteristics, and is expected to be applied in the fields of biomarker detection and imaging.

[0092] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A preparation method of a mesoporous silica-based aggregation-induced emission material, characterized in that, It includes the following steps: Step 1: Prepare dendritic mesoporous silica. Tetraethyl orthosilicate is used as the silicon source to prepare dendritic mesoporous silica; hydrophobically modify the surface of the dendritic mesoporous silica. The reagent used for hydrophobic modification is a diacid with C8 - C18, and the volume ratio to tetraethyl orthosilicate is 1:8 - 1:

24. Step 2: Load AIE molecules on the dendritic mesoporous silica to obtain a mesoporous silica-based aggregation-induced emission material.

2. The preparation method of the mesoporous silicon-based aggregation-induced emission material according to claim 1, wherein: In the said Step 1, dendritic mesoporous silica is prepared by the sol-gel method.

3. The preparation method of the mesoporous silicon-based aggregation-induced emission material according to claim 1, characterized in that: The AIE molecules in the said Step 2 carry a positive charge and a hydrophobic end or have a covalent grafting group.

4. The preparation method of the mesoporous silicon-based aggregation-induced emission material according to claim 3, wherein: The AIE molecules in the said Step 2 are:

5. The preparation method of the mesoporous silicon-based aggregation-induced emission material according to claim 1, characterized in that: In the said Step 2, the dendritic mesoporous silica is dispersed in dimethyl sulfoxide, and a dimethyl sulfoxide solution of AIE molecules is added and stirred to obtain a mesoporous silica-based aggregation-induced emission material.

6. The preparation method of the mesoporous silicon-based aggregation-induced emission material according to claim 5, characterized in that: In the said Step 2, the mass ratio of AIE molecules to dendritic mesoporous silica is 1:200 - 6:200, the stirring temperature is 25 - 80 °C, and the stirring time is 4 - 24 h.

7. Use of the mesoporous silica-based aggregation-induced emission material obtained by the preparation method of the mesoporous silica-based aggregation-induced emission material according to any one of claims 1 - 6 in ion detection, in vitro detection of biomarkers, or fluorescence imaging.

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