Preparation method of a stimulus-responsive ultrathin peptoid nanobelt

Abstract

The application discloses a preparation method of a stimulus-responsive ultrathin peptoid nanoribbon, and comprises the following steps: step one, synthesizing azobenzene n-pentyl AZO with an alkyl chain; step two, synthesizing a ternary alternating peptoid (Pep) by solid-phase subunit synthesis, taking azobenzene n-pentyl AZO, octylamine and 2-methoxyethylamine as monomers; and step three, dissolving the ternary alternating peptoid in an organic solvent by a solvent evaporation-induced self-assembly technology, adding an equal amount of deionized water, slowly evaporating the organic solvent at 4 DEG C, and obtaining the ultrathin peptoid nanoribbon PNR. The application can combine the unique molecular arrangement in the self-assembly process of the alternating copolymer and the excellent chemical and thermal stability of the peptoid, so as to obtain the nanoribbon with excellent performance; the peptoid molecule is obtained by the solid-phase subunit synthesis technology, the synthesis method is simple and the sequence is controllable; and the self-assembly method is the solvent evaporation-induced self-assembly, so that the operation is simple and the repeatability is high.

Description

Technical Field

[0001] This invention relates to the field of nanoribbon preparation technology, and in particular to a method for preparing stimulus-responsive ultrathin peptide nanoribbons. Background Technology

[0002] Ultrathin nanomaterials possess unique advantages such as large specific surface area, controllable permeability, low specific gravity, and few defects, making them promising candidates for fabricating high-performance, small-sized nanodevices (Accounts of Chemical Research, 2018, 51, 436). Furthermore, compared to conventional materials, the low bending stiffness of ultrathin materials enables them to respond sensitively to milder environmental stimuli, which is of great significance for the fabrication of stimulus-responsive smart nanomaterials. One-dimensional organic ultrathin nanomaterials have attracted widespread research interest over the past few decades due to their importance in understanding dimensional confined transport phenomena and fabricating nanodevices and nanosensors with unique electrical, mechanical, and optical properties (Accounts of Chemical Research, 2008, 41, 1674). Although various methods have been developed for fabricating one-dimensional organic nanomaterials, such as electrospinning, template-assisted methods, and template-free methods, fabricating one-dimensional stimulus-responsive smart organic ultrathin nanomaterials with dimensions smaller than 3 nm remains a challenging task.

[0003] Molecular self-assembly is an advanced technique for preparing nanomaterials with customizable chemical properties and precise molecular composition. Various one-dimensional nanostructures have been reported through the self-assembly of amphiphilic molecules (Chemical Society Reviews, 2018, 47, 5491). Early studies on the self-assembly of amphiphilic alternating copolymers provided an effective method for developing organic ultrathin nanomaterials with molecular-scale dimensions. However, regrettably, research on the self-assembly of amphiphilic alternating copolymers, an important polymer topology, is still in its early stages, especially for sequence-controlled alternating copolymers (Chemistry-a European Journal, 2019, 25, 4255).

[0004] Peptides are sequence-controlled molecules that combine the advantages of synthetic polymers and biopolymers. They possess unique advantages, such as a lack of main-chain hydrogen bonds and chirality, excellent side-chain diversity, high protease resistance, and excellent chemical and thermal stability. Therefore, peptides have been developed as peptide mimics, capable of self-assembling into various hierarchical nanoaggregates through simple side-chain chemical self-assembly (Accounts of Chemical Research, 2021, 54, 81). The ability to respond to external stimuli is an important hallmark of life, representing a significant trend in the development of peptide-based nanomaterials.

[0005] Light, as a commonly used stimulus, can not only remotely modulate nanomaterials in a non-contact and non-destructive manner, but also precisely stimulate materials by adjusting the irradiation intensity and duration (Journal of the American Chemical Society, 2018, 140, 8027). However, due to the cumbersome synthesis and self-assembly processes, reports on the preparation of stimulus-responsive one-dimensional energy ultrathin nanomaterials by combining sequence-controllable peptides with photoresponsive groups are still rare. Summary of the Invention

[0006] This invention provides a method for preparing stimulus-responsive ultrathin peptide nanoribbons, which combines the unique molecular arrangement during the self-assembly of alternating copolymers with the excellent chemical and thermal stability of peptides to obtain high-performance nanoribbons. The peptide molecules used are obtained through solid-phase submonomer synthesis technology, which is simple and the sequence is controllable. The self-assembly method used is solvent evaporation-induced self-assembly, which is simple to operate and highly reproducible.

[0007] To address the aforementioned technical problems, this invention provides a method for preparing stimulus-responsive ultrathin peptide-like nanoribbons, comprising the following steps: Step 1: Synthesize n-pentyl AZO with alkyl chains; Step 2: A three-component alternating peptide (Pep) was synthesized using solid-phase submonomer synthesis with azobenzene n-pentyl AZO, octane and 2-methoxyethylamine as monomers. Step 3: Using solvent evaporation-induced self-assembly technology, the three alternating peptides were dissolved in an organic solvent, and an equal amount of deionized water was added. The organic solvent was slowly evaporated at 4 °C to obtain ultrathin peptide nanoribbons PNR. Step 4: Irradiate the diluted peptide-like nanoribbons with ultraviolet light at a wavelength of 365 nm to obtain an aqueous solution of spherical micelles. Then irradiate the aqueous solution of spherical micelles with visible light at a wavelength of 450 nm to restore the spherical micelles to ultrathin nanoribbons.

[0008] As a preferred embodiment of the above technical solution, the molecular structural formula of n-pentyl AZO is: .

[0009] As a preferred embodiment of the above technical solution, the molecular structure of the three-component alternating peptide (Pep) is as follows: .

[0010] As a preferred embodiment of the above technical solution, in step two, the ternary alternating peptide is a peptide with a topological structure in which three side chain groups—azophenyl, n-octyl, and methoxy—are arranged alternately, and the molecular weight of the peptide is 2221.98.

[0011] As a preferred embodiment of the above technical solution, in step three, the organic solvent is tetrahydrofuran.

[0012] As a preferred embodiment of the above technical solution, in step three, the amount of the three alternating peptides is 2 μmol, which is dissolved in 1 mL of organic solvent, followed by the addition of 1 mL of deionized water, and ultrasonic treatment for 2 min to obtain a clear peptide solution.

[0013] As a preferred embodiment of the above technical solution, in step three, the time for the organic solvent to evaporate is 7 days.

[0014] As a preferred embodiment of the above technical solution, in step four, the light intensity of ultraviolet and visible light is 175 mW / cm². 2 The exposure time for ultraviolet light is 2 hours, and the exposure time for visible light is 1 hour.

[0015] As a preferred embodiment of the above technical solution, in step four, the thickness of the ultrathin nanoribbon is 2.2 nm.

[0016] This invention provides a method for preparing stimulus-responsive ultrathin peptide nanoribbons, which are obtained through the self-assembly of three alternating peptides. Due to the unique molecular arrangement of the alternating peptides during self-assembly, the self-assembled nanoribbons have an ultrathin structure with a thickness of only 2.2 nm. Due to the photoisomerization properties of azobenzene, the ultrathin peptide nanoribbons of this invention will transform into spherical micelles under ultraviolet light irradiation and will transform back into ultrathin nanoribbons under visible light irradiation. This invention uses peptides as raw materials and introduces self-assembly technology into the preparation process of nanoribbons. It combines the unique molecular arrangement during the self-assembly of alternating copolymers with the excellent chemical and thermal stability of peptides to obtain high-performance nanoribbons. The peptide molecules used are obtained through solid-phase submonomer synthesis technology, which is simple and has controllable sequences. The self-assembly method used is solvent evaporation-induced self-assembly, which is simple to operate, highly reproducible, and can prepare high-concentration ultrathin peptide solutions, which is beneficial for subsequent applications. The nanoribbon involved in this invention has a thickness of only 2.2 nm, which is much thinner than most nanoribbons reported to date. The ultrathin characteristic increases the specific surface area of ​​the nanoribbon and shortens the distance from the nanoribbon core to the canopy, which is beneficial for the loading of metal nanoparticles, small molecules, etc. The ultrathin peptide-like nanoribbons of this invention exhibit photoresponsiveness, undergoing a reversible transition between the nanoribbons and spherical micelles under ultraviolet and visible light irradiation, making them a stimulus-responsive smart nanomaterial. The method is simple to operate and uses common equipment, providing a simple and effective way to prepare responsive smart nanomaterials.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0018] Figure 1 It is an azobenzene monomer n-pentyl AZO 1 H NMR spectrum; Figure 2 This is the MALDI-TOF MS pattern of the amphiphilic ternary alternating peptide Pep; Figure 3 These are TEM images of stimulus-responsive ultrathin peptide-like nanoribbons (PNRs). Figure 4 These are AFM images of stimulus-responsive ultrathin peptide nanoribbons (PNRs). Figure 5 This is the UV-Vis spectrum of PNR in aqueous solution; Figure 6 These are TEM images of spherical micelles obtained after ultraviolet light irradiation; Figure 7 These are DLS images of spherical micelles obtained after ultraviolet light irradiation; Figure 8 This is a TEM image showing how spherical micelles transform back into nanoribbons after being irradiated with visible light. Detailed Implementation

[0019] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0020] Example 1: See Figure 1-8 This invention provides a method for preparing stimulus-responsive ultrathin peptide nanoribbons, comprising the following steps: Step 1: Synthesize n-pentyl AZO with alkyl chains; Step 2: Through solid-phase submonomer synthesis, a three-component alternating peptide (Pep) was synthesized using azobenzene n-pentyl AZO, octylamine and 2-methoxyethylamine as monomers. The three-component alternating peptide is a peptide with a topological structure in which three side chain groups of azobenzene, n-octyl and methoxy are arranged alternately. The molecular weight of the peptide is 2221.98. Step 3: Using solvent evaporation-induced self-assembly technology, the three alternating peptides were dissolved in an organic solvent, and an equal amount of deionized water was added. The organic solvent, tetrahydrofuran, was slowly evaporated at 4 °C. The amount of the three alternating peptides was 2 μmol, dissolved in 1 mL of organic solvent. Then, 1 mL of deionized water was added, and the solution was sonicated for 2 min to obtain a clear peptide solution. The time for evaporating the organic solvent was 7 days, resulting in ultrathin peptide nanoribbons (PNR). Step 4: Irradiate the diluted peptide-like nanoribbons with ultraviolet light at a wavelength of 365 nm to obtain an aqueous solution of spherical micelles. Then, irradiate the aqueous solution of the spherical micelles with visible light at a wavelength of 450 nm to restore the spherical micelles into ultrathin nanoribbons. The intensity of the ultraviolet and visible light is 175 mW / cm². 2 The ultraviolet light irradiation time was 2 hours, the visible light irradiation time was 1 hour, and the thickness of the ultrathin nanoribbon was 2.2 nm.

[0021] In a further embodiment of this example, the molecular structural formula of n-pentyl AZO is: .

[0022] The molecular structure of the triple alternating peptide (Pep) is as follows: .

[0023] This embodiment provides a method for preparing stimulus-responsive ultrathin peptide nanoribbons, obtained through the self-assembly of three alternating peptides. Due to the unique molecular arrangement of the alternating peptides during self-assembly, the self-assembled nanoribbons have an ultrathin structure with a thickness of only 2.2 nm. Due to the photoisomerization properties of azobenzene n-pentyl AZO, the ultrathin peptide nanoribbons of this invention transform into spherical micelles under ultraviolet light irradiation, and revert back to ultrathin nanoribbons under visible light irradiation. This embodiment uses peptides as raw materials and introduces self-assembly technology into the nanoribbon preparation process. This combines the unique molecular arrangement during the self-assembly of alternating copolymers with the excellent chemical and thermal stability of peptides, resulting in high-performance nanoribbons. The peptide molecules used are obtained through solid-phase submonomer synthesis technology, which is simple and has a controllable sequence. The self-assembly method used is solvent evaporation-induced self-assembly, which is simple to operate, highly reproducible, and can prepare high-concentration ultrathin peptide solutions, which is beneficial for subsequent applications. Using the technical solution of this embodiment, a method for preparing stimulus-responsive ultrathin peptide nanoribbons with high yield, low cost, simple operation, and low equipment requirements can be achieved. This method can efficiently prepare ultrathin peptide nanoribbons with a thickness of only 2.2 nm, which undergo reversible morphological transformation upon irradiation with ultraviolet and visible light.

[0024] Example 2: Based on Example 1, this example proposes a method for preparing stimulus-responsive ultrathin peptide nanoribbons, including the following steps: 1. Synthesis of the azobenzene monomer n-pentylAZO: 5 g of 4-aminophenylethylamine, 8.41 g of di-tert-butyl dicarbonate, and 0.49 g of 4-dimethylaminopyridine (DMAP) were added to a 250 mL single-necked round-bottom flask and dissolved in 100 mL of tetrahydrofuran (THF). The mixture was stirred at room temperature for 24 h. The crude product was purified by column chromatography (eluent was n-hexane:ethyl acetate = 16:1-4:1) to obtain intermediate product A. Add 3g of the above intermediate product A to a 500mL single-necked round-bottom flask and dissolve it in 50mL of dichloromethane (DCM). Add 16g of potassium persulfate (OXONE) to a 100mL beaker and dissolve it in 70mL of deionized water to obtain an aqueous solution of potassium persulfate. Slowly add the potassium persulfate aqueous solution dropwise to the above single-necked round-bottom flask while stirring vigorously with a magnetic stir bar. After reacting at room temperature for 16h, separate the liquid and take the lower organic phase. Remove the solvent using a rotary evaporator to obtain intermediate product B. The intermediate product B was directly transferred to a 250 mL single-necked round-bottom flask, and 2.1 g of 4-pentylaniline was added. It was then dissolved in 40 mL of acetic acid (AcOH). After stirring at room temperature for 72 h, the acetic acid was neutralized with excess sodium hydroxide. The crude product was obtained by extraction with DCM. The crude product was purified by column chromatography (eluent: hexane: ethyl acetate = 25:1) to obtain intermediate product C. The intermediate product C was transferred to a 500 mL single-necked round-bottom flask and dissolved in 150 mL of methanol (MeOH). 50 mL of 12 mol / L concentrated hydrochloric acid (HCl) was added to a 250 mL beaker and diluted with 100 mL of methanol. The diluted hydrochloric acid was slowly added dropwise to the single-necked round-bottom flask. The mixture was stirred at room temperature for 16 h. The hydrochloric acid was then neutralized with excess sodium hydroxide. Methanol was removed by rotary evaporation. The product was then extracted with dichloromethane and the dichloromethane was removed by rotary evaporation to obtain the azobenzene monomer n-pentylAZO, which was an orange-yellow powder.

[0025] (2) Synthesis of the peptide molecule Pep: 100 mg of Rink resin was placed in a 6 mL solid-phase extraction column, and 3 mL of a 20% (v / v) 4-methylpiperidine / N,N'-dimethylformamide (DMF) mixed solution was added. The column was then shaken at room temperature for 40 minutes to remove the Fmoc group. The column was then washed three times with DMF. During the acylation reaction, 1.5 mL of a 0.6 mol / L bromoacetic acid DMF solution and 0.4 mL of a 50% (v / v) N,N'-diisopropylcarbodiimide (DIC) / DMF mixed solution were added. The column was shaken at room temperature for 10 minutes. After the reaction, the column was washed with DMF. Three times, during the SN2 reaction, 1.5 mL of 0.6 mol / L DMF solution of n-pentylAZO, octane, or 2-methoxyethylamine was added, and the reaction was shaken at room temperature for 10 min. After the reaction, the product was washed three times with DMF. The above steps were repeated until the three alternating peptide Pep was synthesized. A 95% aqueous solution of trifluoroacetic acid (TFA) was added, and the mixture was shaken at 40 °C for 40 min to separate the peptide molecules from the Rink resin. After filtering to remove the resin, the trifluoroacetic acid was dried with nitrogen. The obtained product was centrifuged three times in diethyl ether to obtain a pure peptide.

[0026] (3) Preparation of ultrathin peptide nanoribbons (PNR) Take 2 μmol Pep into a 5 mL sample bottle, add 1 mL tetrahydrofuran and 1 mL deionized water, mix well to obtain a clear and transparent solution, and then place it in a freezer at 4 °C to slowly evaporate. After seven days, a stable aqueous solution of ultrathin peptide nanoribbons can be obtained.

[0027] (4) Reversible morphology transformation between ultrathin nanoribbons and spherical micelles Because the azobenzene chromophore undergoes reversible cis-trans isomerization under ultraviolet and visible light irradiation, the self-assembly behavior of peptide molecules also changes accordingly. Using light with an intensity of 175 mW / cm²... 2A spherical micelle aqueous solution can be obtained by irradiating the nanoribbon aqueous solution with a point light source with a wavelength of 365nm for 2 hours. In order to avoid the influence of photothermal effect on self-assembly behavior, the aqueous solution of the assembly is subjected to an ice-water bath during the ultraviolet light irradiation process. Using a light intensity of 175mW / cm 2 When the aqueous solution of spherical micelles is irradiated with a point light source with a wavelength of 450 nm for 1 hour, the spherical micelles can be restored to the morphology of nanoribbons. In order to avoid the influence of photothermal effect on self-assembly behavior, the aqueous solution of the assembly is also subjected to an ice water bath during visible light irradiation.

[0028] In the operation steps of this embodiment: azobenzene monomer n-pentyl AZO 1 H-NMR spectra were measured on an AVANCE 400 (400 MHz) NMR spectrometer with deuterated DMSO as solvent at 25 °C. The molecular weight of Pep was measured by matrix-assisted laser desorption / ionization time-of-flight mass spectrometry (MALDI-TOF MS) using an ABI4800plus instrument. TEM images were obtained using a JEM-1400 transmission electron microscope with an accelerating voltage of 100kV. Dynamic light scattering (DLS) data were obtained using ZETASIZER Nano series instruments; AFM images were obtained using a FastScan Bio atomic force microscope. The ultraviolet light source is a Uvata UP114 lamp with a wavelength of 365 nm and an intensity of 175 mW / cm². 2 The visible light source is an Uvata UP114 lamp with a wavelength of 450 nm and an intensity of 175 mW / cm². 2 .

[0029] The ultrathin peptide-like nanoribbons prepared in this embodiment are photoresponsive, exhibiting a reversible transition between the nanoribbons and spherical micelles under ultraviolet and visible light irradiation, making them a stimulus-responsive smart nanomaterial. This method is simple to operate and uses common equipment, providing a simple and effective way to prepare responsive smart nanomaterials.

[0030] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing stimulus-responsive ultrathin peptide-like nanoribbons, characterized in that, Includes the following steps: Step 1: Synthesize n-pentyl AZO with alkyl chains; Step 2: A three-component alternating peptide (Pep) was synthesized via solid-phase monomer synthesis using azobenzene n-pentyl AZO with alkyl chains, octane, and 2-methoxyethylamine as monomers. The molecular structure of azobenzene n-pentyl AZO with alkyl chains is as follows: ； Step 3: Using solvent evaporation-induced self-assembly technology, the three alternating peptides were dissolved in an organic solvent, and an equal amount of deionized water was added. The organic solvent was slowly evaporated at 4 °C to obtain ultrathin peptide nanoribbons (PNRs). Step 4: Irradiate the diluted peptide-like nanoribbons with ultraviolet light at a wavelength of 365 nm to obtain an aqueous solution of spherical micelles. Then irradiate the aqueous solution of spherical micelles with visible light at a wavelength of 450 nm to restore the spherical micelles to ultrathin nanoribbons.

2. The method for preparing a stimulus-responsive ultrathin peptide nanoribbon according to claim 1, characterized in that, The molecular structure of the triple alternating peptide (Pep) is as follows: 。 3. The method for preparing a stimulus-responsive ultrathin peptide nanoribbon according to claim 1, characterized in that, In step two, the ternary alternating peptide is a peptide with a topological structure in which three side chain groups—azophenyl, n-octyl, and methoxy—are arranged alternately, and the molecular weight of the peptide is 2221.

98.

4. The method for preparing a stimulus-responsive ultrathin peptide nanoribbon according to claim 1, characterized in that, In step three, the organic solvent is tetrahydrofuran.

5. The method for preparing a stimulus-responsive ultrathin peptide nanoribbon according to claim 1, characterized in that, In step three, 2 μmol of the three alternating peptides were dissolved in 1 mL of organic solvent, followed by the addition of 1 mL of deionized water, and the mixture was sonicated for 2 min to obtain a clear peptide solution.

6. The method for preparing a stimulus-responsive ultrathin peptide nanoribbon according to claim 1, characterized in that, In step three, the time for the organic solvent to evaporate is 7 days.

7. The method for preparing a stimulus-responsive ultrathin peptide nanoribbon according to claim 1, characterized in that, In step four, the intensity of ultraviolet and visible light is 175 mW / cm². 2 The exposure time for ultraviolet light is 2 hours, and the exposure time for visible light is 1 hour.

8. The method for preparing a stimulus-responsive ultrathin peptide nanoribbon according to claim 1, characterized in that, In step four, the thickness of the ultrathin nanoribbon is 2.2 nm.

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