Method for packaging fluorophore based on triptycene nano-film

Abstract

The invention discloses a method for packaging a fluorophore based on a triptycene nano film. The preparation method comprises the following steps: firstly, preparing a nano-film taking triptycene as a core fragment through gas-liquid interface assembly and condensation reaction, loading the nano-film on quartz glass, and carrying out freeze-drying treatment in a wet state to keep the pore structure of the nano-film not collapsed; then, a fluorophore solution is dropwise added to the nano-film, and after a solvent is naturally volatilized, fluorophores are uniformly dispersed in the nano-film, so that space and electron isolation of the fluorophores is realized, and the flexible and uniform fluorescent nano-film is obtained. The fluorophore packaged by the method comprises coumarins (such as 7-(diethylamino) coumarin-3-nitrile and coumarin 6), acridine (such as acridine orange), xanthene (such as rhodamine 6G and rhodamine B), quinoneimine (such as Nile red) and the like. In addition, the optical property and the sensing behavior of the obtained fluorescent nano-film are consistent with the optical property and the sensing behavior of a fluorophore in a solution state. Therefore, the method has universality and fidelity.

Description

Technical Field

[0001] The invention belongs to the technical field of encapsulating fluorophores, and in particular relates to a method for encapsulating fluorophores based on triplasene nanofilms. Background Art

[0002] Fluorophores have attracted extensive attention due to their unique optical properties in solution, which have led to their widespread application in disease diagnosis, photonic devices, and bioimaging. However, fluorophores suffer from the problem of inconsistent optical properties between the solid and solution states, exhibiting quenched emission, low quantum yield (QY), spectral broadening, and luminescence red shift in the aggregated or solid state due to aggregation-induced quenching (ACQ) or aggregation-induced emission (AIE) effects. In addition, continuous light excitation of fluorophores can lead to fluorescence decay or fading, known as photobleaching. Photobleaching not only causes the luminescence intensity to decay rapidly over time, but also seriously impairs the long-term optical properties of the material. These two effects remain the main bottlenecks that hinder their practical application.

[0003] At present, most studies still modify bulky groups on fluorophores to destroy stacking. In addition, a widely used method is to embed fluorophores into non-fluorescent matrices such as small molecules (pillar aromatics, cucurbiturils, cyclodextrins), organic frameworks (COFs, MOFs), polymers (PMMA, PVA) and inorganic materials (porous silica) by co-assembly or doping. Although these methods inhibit fluorophore aggregation and improve their photochemical stability to a certain extent, they mainly exist in powder form, have poor processability, and are difficult to meet the large-scale application requirements of complex devices. Although fluorophores can be doped into polymer materials to obtain complete fluorescent films, in sensing applications, such films have a dense internal environment, which limits the interaction between fluorophores and analytes. Although we have previously developed a nanofilm for encapsulating fluorophores, subsequent studies have found that due to the small size of the monomers used and the collapse of the pore size of the nanofilm during natural drying, there will still be certain aggregates when encapsulating fluorophores with larger structures. Therefore, it is urgent to develop a substrate that can effectively inhibit fluorophore aggregation and photobleaching and maintain porosity. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems of the above-mentioned prior art and provide a method for encapsulating fluorophores based on tris-discene nanofilms. The method has universality and fidelity. The prepared fluorescent nanofilm is flexible, uniform and ultra-thin, and effectively suppresses the aggregation and photobleaching of fluorophores. The nanofilm uses pores to achieve spatial and electronic isolation of fluorophores. Compared with the aggregation state of fluorophores or encapsulation in dense polymer films, the utilization rate of fluorophores in sensing is greatly improved, and the same sensing behavior as that of fluorophores in solution is exhibited.

[0005] The method for encapsulating fluorophores based on triplasene nanofilm provided by the present invention comprises the following steps:

[0006] Step 1: Preparation of tridiscene nanofilm

[0007] Dissolving tristyrene polyamine and tristyrene polyaldehyde in dimethyl sulfoxide to obtain a precursor solution; dropping the precursor solution on a glass substrate, and carrying out a Schiff base condensation reaction for 2 to 6 hours at room temperature and a humidity of 50% to 80% to form a nanofilm at a gas-liquid interface; washing the nanofilm with secondary water, scooping up the nanofilm with quartz glass, and freeze-drying the nanofilm to obtain a tristyrene nanofilm; wherein the tristyrene polyamine is 2,3,6,7,14,15-hexamidotristyrene, and the tristyrene polyaldehyde is 4,4',4",4"',4"",4""'-(9,10-dihydro-9,10-[1,2]benzanthracene-2,3,6,7,14,15-hexyl)hexabenzaldehyde.

[0008] Step 2: Encapsulation of fluorophores in triskelion nanofilms

[0009] The fluorophore is dissolved in a solvent and dropped onto the trisciamene nanofilm. After the solvent evaporates at room temperature, the fluorophore is evenly dispersed in the trisciamene nanofilm to obtain a fluorescent nanofilm.

[0010] In the above step 1, the molar ratio of the tris(vinyl)polyamine to the tris(vinyl)polyaldehyde is preferably 1-1.25:1.

[0011] In the above step 1, it is further preferred that the total mass concentration of tris(vinyl)polyamine and tris(vinyl)polyaldehyde in the precursor solution is 0.5% to 2%.

[0012] In the above step 2, the fluorophore includes one or more fluorescent compounds selected from coumarins, such as 7-(diethylamino)coumarin-3-carbonitrile (DCC) and coumarin 6 (C6); acridines, such as acridine orange (AO); xanthenes, such as rhodamine 6G (R6G) and rhodamine B (RhB); or quinoneimines, such as Nile red (NR).

[0013] The molecular size is less than 2nm in at least two directions: x, y and z.

[0014]

[0015]

[0016] In the above step 2, the concentration of the fluorophore in the solvent is preferably 1.0×10 -6 ~1.0×10 -3 mol / L.

[0017] In the above step 2, the solvent is selected from any one of methanol, ethanol and secondary water.

[0018] Fluorophores used

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention forms a flexible nanofilm with tristyrene as a core fragment through assembly and condensation reaction of tristyrene polyamine and tristyrene polyaldehyde at the gas-liquid interface, and disperses a fluorophore solution in the nanofilm by drop coating to obtain a fluorescent nanofilm. The nanofilm of the present invention can keep its porous structure from collapsing by freeze-drying in a wet state, and can be used to encapsulate fluorophores with larger structures to inhibit the aggregation of fluorophores, perfectly convert the optical properties of fluorophores from solution to solid state, and improve the photochemical stability of fluorophores. Compared with fluorophore powders, this method significantly improves their quantum yield and photostability in solids, while maintaining high fidelity of optical properties. The method also replicates the sensing behavior of fluorophores in solution for HCl gas and NH3 gas to the solid state. The method has wide applicability and potential, and provides a general method for improving the optical properties of fluorophores in various applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a photograph of the tridiscene nanofilm prepared in Example 1.

[0022] Figure 2 This is the AFM of the nanofilm in Example 1 after natural drying and freeze drying.

[0023] Figure 3 These are fluorescence photographs of different fluorophores in Example 1 in solution, solid state, and encapsulated in triplasene nanofilms.

[0024] Figure 4 1 is the fluorescence spectra of different fluorophores in Example 1 in solution and encapsulated in triplasene nanofilm.

[0025] Figure 5 It is the wide angle X-ray scattering (WAXS) spectra of the triplascenes nanofilm and RhB in powder state, solution state and encapsulated in the triplascenes nanofilm in Example 1.

[0026] Figure 6 It is a finite state machine composed of three fluorescent nanofilms and their photos under the stimulation of ultraviolet light or HCl / NH3 gas in Example 1.

[0027] Figure 7It is the fluorescence spectrum of the fluorescent nanofilm obtained by mixing the two fluorophores in different proportions in Example 2 and then dropping them into the tridiscene nanofilm, wherein A, B, C, D, E, and F correspond to the fluorescent nanofilms obtained when the molar ratio of DCC to NR is 1:0, 1:0.75, 1:1, 1:2, 1:3, and 0:1, respectively.

[0028] Figure 8 yes Figure 7 The corresponding CIE coordinate diagram and the corresponding photo of the fluorescent nanofilm emitting white light. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0030] Example 1

[0031] 1. Preparation of triplasene nanofilm (C[4]P-FTP)

[0032] 0.28 mg (0.8 mmol) of 2,3,6,7,14,15-hexaaminotriptycene and 0.72 mg (0.8 mmol) of 4,4',4",4"',4"",4""'-(9,10-dihydro-9,10-[1,2]benzanthracene-2,3,6,7,14,15-hexyl)hexabenzaldehyde were dissolved in 200 μL of dimethyl sulfoxide to prepare a precursor solution; 70 μL of the precursor solution was dropped onto a 1.5 cm × 1.5 cm glass substrate, and then a Schiff base condensation reaction was carried out for 3 hours under the induction conditions of a temperature of 25°C and a humidity of 60%. After the reaction, a nanofilm was formed at the gas-liquid interface. The glass substrate was taken out and immersed in secondary water, and the nanofilm floated on the water surface (such as Figure 1 As shown), the nanofilm was washed with secondary water, and then the nanofilm was picked up with a quartz glass with a diameter of 1 cm, and the triptycene nanofilm was obtained after freeze-drying.

[0033] At the same time, natural drying was used to replace freeze drying to obtain nanofilms for comparative experiments.

[0034] Depend on Figure 2 It can be seen that the nanofilm that has been freeze-dried is thicker than the nanofilm that has been naturally dried, indicating that the nanofilm maintains its pore structure after freeze-drying, while the pore collapse under natural drying conditions makes the film thickness thinner.

[0035] 2. Tridiscene nanofilm encapsulation of fluorophores

[0036] The concentration was 2.5×10 -550 μL of mol / L methanol solutions of 7-(diethylamino)coumarin-3-carbonitrile (DCC), coumarin 6 (C6), acridine orange (AO), rhodamine 6G (R6G), rhodamine B (RhB) and Nile red (NR) were respectively added dropwise onto the triptycene nanofilm, and the methanol was evaporated at room temperature to obtain C[4]P-FTP / DCC, C[4]P-FTP / C6, C[4]P-FTP / AO, C[4]P-FTP / R6G, C[4]P-FTP / RhB and C[4]P-FTP / NR fluorescent nanofilms.

[0037] Depend on Figure 3 It can be seen that the fluorescence photo of the fluorophore encapsulated in the triplasene nanofilm is consistent with the color of the corresponding fluorophore in the methanol solution, while the fluorophore in the powder state shows a red shift in fluorescence color or fluorescence quenching. Figure 4 It can be seen that the fluorescence spectrum of the fluorophore encapsulated in the triplascenene nanofilm is consistent with the fluorescence spectrum of the corresponding fluorophore in the methanol solution. The above results show that the use of the triplascenene nanofilm of the present invention can effectively achieve the isolation of the fluorophore. Figure 5 It can be seen that RhB has obvious WAXS peaks in the powder state, indicating that RhB is in aggregates, while there is no obvious WAXS peak in the methanol solution and encapsulated in the triplasene nanofilm, that is, RhB is isolated by the nanofilm.

[0038] In addition, HCl gas was extracted using a syringe and hit on the fluorescent nanofilm obtained in this embodiment, and the results showed that its fluorescence was quenched. NH3 gas was extracted using a syringe and hit on the nanofilm whose fluorescence was quenched, and the results showed that its fluorescence was restored. This shows that the fluorescent nanofilm obtained by the present invention has sensing performance for HCl gas and NH3 gas.

[0039] The C[4]P-FTP / DCC, C[4]P-FTP / R6G and C[4]P-FTP / NR fluorescent nanofilms prepared in Example 1 were combined into Figure 6 The pattern shown can present different colors under the stimulation of ultraviolet light and HCl / NH3 gas, which are defined as different states, namely states 00, 01, 10 and 11, thereby serving as an information storage material.

[0040] Example 2

[0041] 1. Preparation of tridiscene nanofilm (C[4]P-FTP)

[0042] The tridiscene nanofilm was prepared according to the method of step 1 of Example 1.

[0043] 2. Tridiscene nanofilm encapsulation of fluorophores

[0044] The total concentration of fluorophores was 2.5 × 10 -5 mol / L, DCC and NR were dissolved in methanol at a molar ratio of 1:0, 1:0.75, 1:1, 1:2, 1:3 and 0:1 to prepare solutions. 50 μL of the prepared solutions were dropped onto the triptycene nanofilms, and the methanol was evaporated at room temperature to obtain fluorescent nanofilms of different colors. Figure 7 and Figure 8 It can be seen that the fluorescent nanofilm prepared with a DCC and NR molar ratio of 1:2 exhibits white light emission, and its CIE coordinates are (0.31, 0.32).

Claims

1. A method for encapsulating fluorophores based on triplasene nanofilms, characterized in that: The steps include: Step 1: Preparation of tridiscene nanofilm Dissolving tristyrene polyamine and tristyrene polyaldehyde in dimethyl sulfoxide to obtain a precursor solution; dropping the precursor solution on a glass substrate, and performing a Schiff base condensation reaction for 2 to 6 hours at room temperature and a humidity of 50% to 80% to form a nanofilm at the gas-liquid interface; washing the nanofilm with secondary water, scooping up the nanofilm with quartz glass, and freeze-drying the nanofilm to obtain a tristyrene nanofilm; wherein the tristyrene polyamine is 2,3,6,7,14,15-hexamidotriptyrene, and the tristyrene polyaldehyde is 4,4',4",4"',4"",4""'-(9,10-dihydro-9,10-[1,2]benzanthracene-2,3,6,7,14,15-hexyl)hexabenzaldehyde; Step 2: Encapsulation of fluorophores in triskelion nanofilms The fluorophore is dissolved in a solvent and dropped onto the trisciamene nanofilm. After the solvent evaporates at room temperature, the fluorophore is evenly dispersed in the trisciamene nanofilm to obtain a fluorescent nanofilm.

2. The method for encapsulating fluorophores based on triplasene nanofilm according to claim 1, characterized in that: In step 1, the molar ratio of tris(vinyl)polyamine to tris(vinyl)polyaldehyde is 1-1.25:

1.

3. The method for encapsulating fluorophores based on triplasene nanofilm according to claim 2, characterized in that: In step 1, the total mass concentration of tris(vinyl)polyamine and tris(vinyl)polyaldehyde in the precursor solution is 0.5% to 2.0%.

4. The method for encapsulating fluorophores based on triplasene nanofilm according to claim 1, characterized in that: In step 2, the fluorophore is selected from any one or more fluorescent compounds of coumarins, acridines, xanthenes, and quinoneimines, and the molecular size of the fluorophore is less than 2 nm in at least two directions of x, y, and z.

5. The method for encapsulating fluorophores based on triplasene nanofilm according to claim 1, characterized in that: In step 2, the fluorophore is selected from any one or more of 7-(diethylamino)coumarin-3-carbonitrile, coumarin 6, acridine orange, rhodamine 6G, rhodamine B, and Nile red.

6. The method for encapsulating fluorophores based on triplasene nanofilm according to claim 1, characterized in that: In step 2, the concentration of the fluorophore in the solvent is 1.0×10 -6 ~1.0×10 -3 mol / L.

7. The method for encapsulating fluorophores based on triplasene nanofilm according to claim 1 or 6, characterized in that: In step 2, the solvent is selected from any one of methanol, ethanol, and secondary water.

Images