A method for encapsulating fluorophores based on triscian nano-film

Abstract

The application discloses a method for packaging fluorophores based on tris-dolene nanofilm. First, a nanofilm with tris-dolene as a core segment is prepared through gas-liquid interface assembly and condensation reaction, and is carried on a quartz glass. In a wet state, the pore structure of the nanofilm can be maintained without collapsing through freeze-drying treatment. Then, a fluorophore solution is added dropwise on the nanofilm. After the solvent is naturally evaporated, the fluorophore is uniformly dispersed in the nanofilm, spatial and electronic isolation of the fluorophore is realized, and a flexible and uniform fluorescent nanofilm is obtained. The fluorophore packaged by the method includes coumarin (such as 7-(diethylamino) coumarin-3-carbonitrile and coumarin 6), acridine (such as acridine orange), xanthene (such as rhodamine 6G and rhodamine B) and quinonimine (such as Nile red), etc. In addition, the optical properties and sensing behavior of the obtained fluorescent nanofilm are consistent with the optical properties and sensing behavior of the fluorophore in a solution state. Therefore, the application has universality and fidelity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of encapsulating fluorophores, and particularly relates to a method for encapsulating fluorophores based on a tris-boroxin nanofilm. BACKGROUND

[0002] Fluorophores have attracted extensive attention due to their unique optical properties in solution, making them widely used in disease diagnosis, photonic devices, and biological imaging. However, there is a problem of inconsistency in optical properties between solid and solution states of fluorophores. Due to the aggregation-caused quenching (ACQ) or aggregation-induced emission (AIE) effect, fluorophores exhibit quenched emission, low quantum yield (QY), spectral broadening, and emission redshift in the aggregated or solid state. In addition, continuous optical excitation of fluorophores can lead to fluorescence decay or fading, which is called photobleaching. Photobleaching not only causes rapid decay of luminescence intensity over time, but also seriously damages the long-term optical performance of the material. These two effects are still the main bottleneck hindering their practical application.

[0003] Currently, most studies are still through the modification of large volume groups on the fluorophore to destroy the accumulation. In addition, a widely used method is to embed fluorophores into non-fluorescent substrates such as small molecules (pillar arenes, cucurbituril, cyclodextrin), organic frameworks (COF, MOF), polymers (PMMA, PVA), and inorganic materials (porous silica) through co-assembly or doping. Although these methods inhibit the aggregation of fluorophores to some extent and improve their photochemical stability, they mainly exist in the form of powder, which has poor processability and is difficult to meet the requirements of large-scale application of complex equipment. Although fluorophores doped into polymer materials can also obtain complete fluorescent films, in the sensing application, due to the dense internal environment of such films, the interaction between the fluorophore and the analyte is limited. Although we have previously developed a nanofilm for encapsulating fluorophores, subsequent studies have found that due to the small size of the monomer used and the collapse of the pore size of the nanofilm in natural drying, when encapsulating fluorophores with large structures, there will still be some aggregates. Therefore, there is an urgent need to develop a substrate that can effectively inhibit the aggregation and photobleaching of fluorophores and maintain porosity. SUMMARY

[0004] The purpose of the present application is to overcome the problems of the prior art, and to provide a method for encapsulating fluorophores based on a tris-boroxin nanofilm. The method has universality and fidelity, and the prepared fluorescent nanofilm has the characteristics of flexibility, uniformity, and ultrathinness, effectively inhibiting the aggregation and photobleaching of fluorophores. The nanofilm realizes the spatial and electronic isolation of fluorophores using the pore channel, which greatly improves the utilization rate of fluorophores in sensing compared to the aggregated state or encapsulation in dense polymer films, and exhibits the same sensing behavior as fluorophores in the solution state.

[0005] The method for encapsulating fluorophore based on triptycene nanofilm provided by the application comprises the following steps:

[0006] Step 1: Preparation of triptycene nanofilm

[0007] Triptycene polyamine and triptycene polyaldehyde are dissolved in dimethyl sulfoxide to obtain a precursor solution; the precursor solution is added dropwise on a glass substrate, and a Schiff base condensation reaction is carried out at room temperature and under the induction condition of humidity of 50% to 80% for 2 to 6 hours, so as to form a nanofilm at the gas-liquid interface; the nanofilm is cleaned with distilled water, and then the nanofilm is taken out with a quartz glass, and is subjected to freeze-drying treatment to obtain a triptycene nanofilm; wherein the triptycene polyamine is 2,3,6,7,14,15-hexaaminotriptycene, and the triptycene 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 fluorophore by triptycene nanofilm

[0009] The fluorophore is dissolved in a solvent, and is added dropwise on the triptycene nanofilm; after the solvent is volatilized at room temperature, the fluorophore is uniformly dispersed in the triptycene nanofilm to obtain a fluorescent nanofilm.

[0010] In the above step 1, preferably, the molar ratio of the triptycene polyamine to the triptycene polyaldehyde is 1 to 1.25:1.

[0011] In the above step 1, further preferably, the total mass concentration of the triptycene polyamine and the triptycene polyaldehyde in the precursor solution is 0.5% to 2%.

[0012] In the above step 2, the fluorophore comprises one or more fluorescent compounds selected from the group consisting of coumarin, such as 7-(diethylamino)coumarin-3-carbonitrile (DCC) and coumarin 6 (C6); acridine, such as acridine orange (AO); xanthene, such as rhodamine 6G (R6G) and rhodamine B (RhB); and quinone imine, such as Nile red (NR).

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

[0014]

[0015]

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

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

[0018] Fluorophores used

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

[0020] The present application forms a flexible nanofilm with a triptycene core segment by assembling and condensing triptycene polyamine and triptycene polyaldehyde at the gas-liquid interface. The fluorophore solution is dispersed in the nanofilm by drop coating to obtain a fluorescent nanofilm. The nanofilm of the present application can maintain its porous structure without collapse by freeze-drying treatment in a wet state. The nanofilm can inhibit the aggregation of the fluorophore for encapsulating a larger structure of the fluorophore, perfectly converting the optical properties of the fluorophore from solution to solid state, and improving the photochemical stability of the fluorophore. Compared with the fluorophore powder, the method significantly improves the quantum yield and optical stability of the fluorophore in solid, while maintaining high fidelity of optical performance. The method also replicates the sensing behavior of the fluorophore in solution to solid state under HCl gas and NH3 gas. The method has wide applicability and potential, and provides a universal method for improving the optical performance of the fluorophore in various applications. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a photo of the triptycene nanofilm prepared in Example 1.

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

[0023] Figure 3 is a fluorescence photo of different fluorophores in solution state, solid state, and encapsulated in the triptycene nanofilm in Example 1.

[0024] Figure 4 is a fluorescence spectrum of different fluorophores in solution state and encapsulated in the triptycene nanofilm in Example 1.

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

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

[0027] Figure 7The fluorescence spectra of the fluorescent nanofilms obtained by mixing the two fluorophores in different proportions and dropping them into the tri-color nanofilm in Example 2 are shown. A, B, C, D, E, and F correspond to the fluorescent nanofilms obtained by DCC and NR molar ratios of 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 fluorescent nanofilm emitting white light. Detailed Implementation

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

[0030] Example 1

[0031] 1. Preparation of triterpenoid nanofilms (C[4]P-FTP)

[0032] A precursor solution was prepared by dissolving 0.28 mg (0.8 mmol) of 2,3,6,7,14,15-hexamethylenetriptene 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)hexamethylenealdehyde in 200 μL of dimethyl sulfoxide. 70 μL of the precursor solution was dropped onto a 1.5 cm × 1.5 cm glass substrate, and a Schiff base condensation reaction was carried out for 3 hours under induction conditions of 25 °C and 60% humidity. After the reaction, a nanofilm was formed at the gas-liquid interface. The glass substrate was then removed and immersed in secondary water; the nanofilm floated on the water surface (e.g., ...). Figure 1 As shown, after cleaning the nanofilm with deionized water, the nanofilm was retrieved with a quartz glass with a diameter of 1 cm, and then freeze-dried to obtain a tripterene nanofilm.

[0033] Meanwhile, natural drying was used instead of freeze drying to obtain nanofilms for comparative experiments.

[0034] Depend on Figure 2 It is evident that the freeze-dried nanofilm is thicker than the naturally dried nanofilm, indicating that the freeze-drying process maintained the pore structure of the nanofilm, while the pore collapse under natural drying conditions resulted in a thinner film.

[0035] 2. Encapsulation of phosphors in tridiene nanofilms

[0036] Prepare concentrations of 2.5 × 10⁻⁶. -5mol / L of 7-(diethylamino)coumarin-3-carbonitrile (DCC), coumarin 6 (C6), acridine orange (AO), rhodamine 6G (R6G), rhodamine B (RhB) and Nile red (NR) in methanol, 50 μL of the prepared solution was dropped on the C[4]P-FTP respectively, and 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] It can be seen from the above results that the fluorescence photos of the fluorophores encapsulated in the C[4]P-FTP are consistent with the fluorescence photos of the corresponding fluorophores in methanol solution, while the fluorescence photos of the fluorophores in powder state show red shift or fluorescence quenching. Figure 3 It can be seen from the above results that the fluorescence photos of the fluorophores encapsulated in the C[4]P-FTP are consistent with the fluorescence photos of the corresponding fluorophores in methanol solution, while the fluorescence photos of the fluorophores in powder state show red shift or fluorescence quenching. Figure 4 It can be seen from the above results that the fluorescence photos of the fluorophores encapsulated in the C[4]P-FTP are consistent with the fluorescence photos of the corresponding fluorophores in methanol solution, while the fluorescence photos of the fluorophores in powder state show red shift or fluorescence quenching. Figure 5 It can be seen from the above results that the fluorescence photos of the fluorophores encapsulated in the C[4]P-FTP are consistent with the fluorescence photos of the corresponding fluorophores in methanol solution, while the fluorescence photos of the fluorophores in powder state show red shift or fluorescence quenching.

[0038] In addition, the fluorescence of the fluorescent nanofilms obtained in the above embodiment was quenched by HCl gas, and the fluorescence was recovered by NH3 gas, indicating that the fluorescent nanofilms obtained in the embodiment have sensing performance to 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 the above embodiment 1 were combined into a pattern as shown in Figure 6 The pattern can present different colors under the stimulation of ultraviolet light and HCl / NH3 gas, which is defined as different states, i.e. states 00, 01, 10 and 11, thereby serving as an information storage material.

[0040] Example 2

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

[0042] The triptycene nanofilm was prepared according to the method of step 1 of embodiment 1.

[0043] 2. Encapsulation of fluorophores in triptycene nanofilm

[0044] at a total concentration of 2.5 x 10 -5 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, respectively, to prepare solutions. 50 μL of each solution was added dropwise onto the triptycene nanofilm, and the methanol was allowed to evaporate 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 molar ratio of DCC to NR of 1:2 exhibits white light emission, with CIE coordinates of (0.31, 0.32).

Claims

1. A method for encapsulating a fluorophore based on a triscian nano-film, characterized in that: The method comprises the following steps: Step 1: preparation of triptycene nanofilm Triptycene polyamine and triptycene polyaldehyde are dissolved in dimethyl sulfoxide to obtain a precursor solution; the precursor solution is added dropwise on a glass substrate, and a Schiff base condensation reaction is carried out at room temperature and under the induction condition of humidity of 50-80% for 2-6 hours, so as to form a nanofilm at the gas-liquid interface; the nanofilm is cleaned with deionized water, and then the nanofilm is taken out with a quartz glass, and after freeze-drying treatment, a triptycene nanofilm is obtained; wherein the triptycene polyamine is 2,3,6,7,14,15-hexaaminotriptycene, and the triptycene 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 fluorophore in triptycene nanofilm The fluorophore is dissolved in a solvent, and is added dropwise on the triptycene nanofilm, and after the solvent is volatilized at room temperature, the fluorophore is uniformly dispersed in the triptycene nanofilm to obtain a fluorescent nanofilm.

2. The method of encapsulating fluorophores based on triscian nano-film according to claim 1, characterized in that: In step 1, the molar ratio of the triptycene polyamine to the triptycene polyaldehyde is 1-1.25:

1.

3. The method of encapsulating fluorophores based on triscian nano-film according to claim 2, characterized in that: In step 1, the total mass concentration of the triptycene polyamine and the triptycene polyaldehyde in the precursor solution is 0.5%-2.0%.

4. The method of encapsulating fluorophores based on triscian nano-film according to claim 1, wherein: In step 2, the fluorophore is selected from any one or more of coumarin, acridine, xanthene, quinone imine, and the molecular size of the fluorophore is less than 2nm in at least two directions of x, y and z.

5. The method of encapsulating fluorophores based on triscian nano-film according to claim 1, wherein: 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 of encapsulating fluorophores based on triscian nano-film according to claim 1, wherein: In step 2, the concentration of the fluorophore in the solvent is 1.0 x 10 -6 ~1.0 x 10 -3 mol / L.

7. The method of encapsulating fluorophores based on triscian nano-film according to claim 1 or 6, characterized in that: In step 2, the solvent is selected from any one of methanol, ethanol and deionized water.

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