JP5354591B2 - AMIDE COMPOUND HAVING PHOTOISOMERIZATION GROUP, ORGANIC NANOTUBE COMPRISING SELF-ASSEMBLING THE COMPOUND, AND METHOD FOR PRODUCING THE SAME - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic nanotube facilitating the regulation of formation and disintegration of the nanotube without using heat, an acid, a base, a surfactant or the like, accordingly enabling the inclusion/release of a guest, and formable in a local space. <P>SOLUTION: The organic nanotube is obtained by using a compound obtained by linking a compound having photoisomerization functions like azobenzene, and glycine, diglycine or triglycine, respectively at both terminals of ethylenediamine, and heating and dissolving it in water, and cooling the resultant solution to room temperature. The obtained nanotube easily releases the included guest by light irradiation. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an organic nanotube useful as a functional material such as an inclusion / separation / sustained-release material in the field of pharmaceuticals, chemical products, etc., and in particular, an amide compound to which an aromatic compound having photoisomerization ability is linked, and The present invention relates to an organic nanotube formed by self-assembly of the compound and a method for producing the same.

  At present, porous inorganic materials such as micelles and vesicles formed from surfactants and polymers, zeolites and mesoporous silica are mainly used as inclusion, separation, and drug sustained release materials. . For example, a vesicle is a capsule-like structure having a diameter of several tens of nanometers to several tens of micrometers in which a minute aqueous phase is encapsulated in a lipid membrane, and takes in a large substance such as a protein such as a protein of about 10 to 1000 nm. I can do it. Zeolite mesoporous silica has pores of about 0.1 to 100 nm on the surface, and can take in smaller substances than vesicles.

  There are roughly two ways to release the guest contained in these materials. One is that the material is broken and the guest is released to the outside. In this case, all the guests are released at once. Released to the outside. The other is that the material itself is not broken and the compound is released to the outside by diffusion. In this case, an inorganic mesoporous body that is not easily decomposed in vivo or in the environment is used.

Recently, it has been proposed to use photoisomerization as one of the methods for releasing a guest.
For example, Non-Patent Document 1 succeeds in releasing a dye molecule by light irradiation using a liposome composed of a lipid into which a group having photoisomerization ability is introduced. This is a mechanism in which azobenzene is easily photoisomerized in the liquid crystal (fluid) bilayer membrane constituting the liposome, whereby a gap is formed in the membrane and the guest small molecule leaks out. A number of similar papers have been reported. The release of guest small molecules and their velocities are shown in Membrane fluidity in Non-Patent Documents 2 and 3, in Phase Separation in Non-Patent Document 4, and in Non-Patent Document 5. It has been reported that it is greatly influenced by the packing mode of lipid molecules.
Non-Patent Documents 6 and 7 report examples in which encapsulated guests are released by photoisomerization in vesicles formed by self-assembly of dendron (branched) molecules.
Furthermore, in Patent Document 1, a reversible photoisomerization group is introduced into the pores of a mesoporous body, and the release of the guest encapsulated in the pores by reversible isomerization of the photoisomerization group accompanying light irradiation. It is described that it is possible to promote.

On the other hand, nanotube-like materials having pores of 0.5 to 500 nanometers (hereinafter referred to as nm) are attracting attention as materials representative of nanotechnology.
As a result of studying the synthesis of hollow fiber-like organic nanotubes formed by self-assembly of peptide lipids in which the carboxyl group of a long-chain fatty acid and the N-terminus of an oligopeptide are bound, the present inventors have made transitions with peptide lipids in water. It has been found that a nano-sized hollow fibrous structure is formed by coexisting metal (Patent Document 2, Non-Patent Document 8).

JP 2006-256885 A JP 2004-250797 A

Kunitake, Okahata, Shimomura et al., Chem. Lett., P.421 (1980) Langmuir, 15, p.3424 (1999) Biophys. Acta., 1720, p.28 (2005) Biochem. Biophys. Res. Commun., 276, p.169 (2000) Langmuir, 20, p.1152 (2004) Polymer, 48, p.4466 (2007) Angew.Chem. Int. Ed., 47, p.2959 (2008) Adv.Mater., Adv.Mater., 19, p.242 (2007)

  The pore diameter of the organic nanotube formed by self-assembling the lipid molecules synthesized by the present inventors is a size that partially overlaps the inner pore diameter of the conventional zeolite / mesoporous silica, and the conventional zeolite / mesoporous silica is It solves the problem of having an affinity as a material for inclusion / separation / sustained release of a biological substance such as an organic functional substance or protein because it is an inorganic material. Expected.

However, when forming organic nanotubes by self-organizing lipid molecules, heating above the gel liquid crystal phase transition temperature of the lipid molecules is required. In addition, as a formation method that does not require a heating operation, there are pH stimulation, a surfactant removal method, and the like, but it is necessary to add an acid, a base, and a surfactant directly into the system.
In addition, these methods can be used to form and collapse organic nanotubes (phase transition to liquid crystal) and simultaneously include and release guests, but they are stable against heat, acids, bases, and surfactants. There is also a problem that it is limited to new guests.
Furthermore, high density and uniform packing of nanotubes in local spaces such as nano and micro channels is required in the creation of next generation separation and analysis devices. Nanotubes are introduced directly into local spaces because of their high axial ratio. Is difficult. It is easy to introduce lipid molecules into the local space before self-assembly, but subsequent heating operations, addition of acids, bases, and surfactants are difficult, and nanotubes cannot be formed in the local space. is there.

  The present invention has been made in view of the above circumstances, and it is easy to control the formation and collapse of nanotubes without using heat, acid, base, surfactant, etc. It is an object of the present invention to provide an organic nanotube that can be included / released and an organic nanotube that can be formed in a local space.

Long-chain alkyl has been introduced into the hydrophobic part of the existing lipid molecules that form organic nanotubes. If this can be replaced with aromatic compounds to form organic nanotubes, various functions of aromatic compounds can be achieved. Can be imparted to the nanotube. As mentioned above, some aromatic compounds show isomerization and association behavior in response to external light, and the formation and decay of organic nanotubes, and the inclusion and release of guests are controlled by light. Is possible.
As a result of further investigation by the present inventors to solve the above-mentioned problems, a compound having a photoisomerization function such as azobenzene and oligoglycine (monoglycine, diglycine, triglycine) were connected to both ends of ethylenediamine, respectively. It was found that the compound can be dissolved in water by heating and cooled to room temperature to obtain organic nanotubes. It was also found that the encapsulated guest was easily released by irradiating the obtained organic nanotube with light.

The present invention has been completed based on these findings, and according to the present invention, the following inventions are provided.
[1] the following general formula _{H (NHCH 2 CO) n NHC} 2 H 4 NHCO-R
(In the formula, R represents a residue of an aromatic compound having a reversible photocatalytic function selected from azobenzene, spiropyran, leuco dye, coumarin, anthracene, diphenylbutadiene, or stilbene , and n represents an integer of 1 to 3. )
An amide compound represented by:
[ 2 ] An organic nanotube, wherein the compound according to [1] is self-assembled.
[ 3 ] A method for producing an organic nanotube, comprising heating and dissolving the compound according to [1] in water and cooling to room temperature.
[ 4 ] A method for producing a guest inclusion organic nanotube, comprising dispersing the organic nanotube according to the above [ 2 ] and a compound serving as a guest in water to include the guest.
[ 5 ] A method for releasing a guest from an organic nanotube, wherein the guest is released by irradiating the organic nanotube according to [ 2 ], wherein the guest is included, with ultraviolet rays.

Changes in the structure of the molecule due to isomerization and changes in the balance between hydrophilicity and hydrophobicity have a great influence on molecular packing and aggregate formation. Therefore, according to the present invention, the formation / disintegration of the tube can be controlled by light. This means that the inclusion / release of the guest can be controlled by non-contact stimulation of light.
In the present invention, the wavelength of light can be selected and the rate of inclusion / release can be controlled according to the type of aromatic compound to be amide-bonded to ethylenediamine, which can be expected to be applied to drug delivery systems and nanopipettes. This also makes it possible to form nanotubes simply by irradiating light from lipid molecules introduced into the local space, contributing to the development of next-generation separation and analysis devices.

Electron micrograph of the organic nanotube obtained in Production Example 1 Electron micrograph of organic nanotube obtained in Production Example 2 Electron micrograph of the organic nanotube obtained in Production Example 3 UV-visible absorption spectrum showing the trans-> cis structure isomerization by irradiation with ultraviolet rays of 365 nm and the cis-> trans structure isomerization by irradiation with ultraviolet rays of 436 nm of the aqueous dispersion of organic nanotubes obtained in Production Example 1. Diffuse reflection UV-visible absorption spectrum showing trans-cis isomerization of organic nanotube obtained in Production Example 1 It is a figure which shows the amount of guest discharge | release from the organic nanotube obtained in manufacture example 1, the left side shows discharge | release of the slow guest by pH stimulation, and the right side shows discharge | release of the fast guest by light stimulation.

The organic nanotube of the present invention has the following general formula H (NHCH) in which an aromatic compound having a reversible photoisomerization function such as azobenzene and glycine, diglycine or triglycine are connected to both ends of ethylenediamine by an amide bond, respectively. _{2 CO) n NHC 2 H 4} NHCO-R
(In the formula, R represents a residue of an aromatic compound having a reversible photocatabolic function, and n represents an integer of 1 to 3.)
The compound represented by is self-assembled.
Examples of the aromatic compound having a reversible photocatabolic function include azobenzene, spiropyran, leuco dye, coumarin, anthracene, diphenylbutadiene, and stilbene.

When the compound represented by the above general formula of the present invention is dissolved by heating in water and cooled to room temperature, an organic nanotube formed by self-assembly of the compound is obtained.
The obtained organic nanotube reversibly undergoes photoisomerization in a dispersed state in water and in a solid state. The trans-cis structural change accompanying the photoisomerization of a site having a reversible isomerization function such as azobenzene also affects the tube form, and significantly accelerates the release of the clathrate guest in the hollow cylinder.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to this Example.

<Synthesis of compounds>
Synthesis Example 1: Synthesis of N-glycylaminoethyl-azobenzene-4-carboxylamide A dry methanol solution of ethylenediamine (8.0 g, 0.13 mol) was cooled to −40 ° C., and carbobenzoxyl chloride (1. 1 g, 6.5 mmol) was added dropwise and then stirred. After the solvent was distilled off, 3N HCl was added, and insoluble matters were removed by filtration. The filtrate was adjusted to pH 11 with 2N NaOH and extracted with chloroform and diethyl ether. The organic solvent phase was separated and dried over sodium sulfate. After the solvent was distilled off, vacuum drying was performed at 70 ° C. to obtain aminoethyl-benzoxy-carboxylamide (1.1 g, yield 87%).
The resulting aminoethyl-benzoxy-carboxylamide (0.60 g, 3.1 mmol) and Boc-glycine succinimidyl ester (0.85 g, 3.1 mmol) were stirred in methanol overnight. After the solvent was distilled off, the residue was extracted with chloroform and washed with an aqueous citric acid solution and an aqueous sodium hydrogen carbonate solution. The chloroform phase was collected and dried over sodium sulfate to obtain N-Boc-glycylaminoethyl-benzoxy-carboxylamide (0.74 g, yield 67%).
Next, the N-Boc-glycylaminoethyl-benzoxy-carboxylamide (0.74 g, 2.1 mmol) was dissolved in methanol, catalytic hydrogenation was performed in the presence of Pd / C, and N-Boc-glycylamino was obtained. Ethylamine was obtained. After removing Pd / C by filtration, azobenzene-4-carboxylic acid (0.47 g, 2.1 mmol) was added, and the mixture was stirred overnight in the presence of a condensing agent DMT-MM (0.57 g, 2.1 mmol). After the solvent was distilled off, the residue was dissolved in chloroform and subjected to silica gel column chromatography (developing solution: a mixed solvent of chloroform, ethyl acetate and methanol), and N-Boc-glycylaminoethyl-azobenzene-4-carboxylamide (0. 57 g, 65% yield) was isolated.
Further, the N-Boc-glycylaminoethyl-azobenzene-4-carboxylamide (0.57 g, 1.4 mmol) was dissolved in N, N′-dimethylformamide, and 4N hydrochloric acid-acetic acid was cooled to −5 ° C. Was added in several batches to 50 equivalents and stirred overnight. After distilling off the solvent and acid, the residue was washed with chloroform and water to obtain N-glycylaminoethyl-azobenzene-4-carboxylamide (0.39 g, yield 88%).

The analysis results of the obtained compound by H-NMR, elemental analysis, and electrospray ionization mass spectrometry were as follows.
H-NMR (400 MHz, DMSO-d6) 3.32 (2H, t, -CH2-), 3.39 (2H, t, -CH2-), 3.52 (2H, s, N-CH2-C = O), 7.63 ( 3H, dd, benzene), 7.93 (2H, dd, benzene), 7.96 (2H, d, benzene), 8.09 (2H, d, benzene), 8.58 (1H, t, NH), 8.81 (1H, t, NH )
Elemental analysis (C17H19N5O2)
Calculated (%) C 62.75, H 5.89, N 21.52
Actual value (%) C 61.34, H, 5.98, N 20.95
Electrospray ionization mass spectrometry
m / z = 348.1 (+ Na ⁺ )

Synthesis Example 2: Synthesis of N-glycylglycylaminoethyl-azobenzene-4-carboxylamide The aminoethyl-benzoxy-carboxylamide (0.50 g, 2.6 mmol) and Boc-glycylglycine (0.60 g, 2 6 mmol) was stirred overnight in methanol in the presence of condensing agent DMT-MM (1.1 g, 3.9 mmol). After the solvent was distilled off, the residue was dissolved in chloroform and subjected to silica gel column chromatography (developing solution: mixed solvent of chloroform, ethyl acetate and methanol) to give N-Boc-glycylglycylaminoethyl-benzoxy-carboxylamide (0.46 g). Yield 45%).
The obtained N-Boc-glycylglycylaminoethyl-benzoxy-carboxylamide (0.46 g, 1.2 mmol) was dissolved in methanol, catalytic hydrogenation was performed in the presence of Pd / C, and N-Boc-glycylglycol was obtained. Silaminoethylamine was obtained. After removing Pd / C by filtration, azobenzene-4-carboxylic acid (0.47 g, 2.1 mmol) was added, and the mixture was stirred overnight in the presence of a condensing agent DMT-MM (0.57 g, 2.1 mmol). After the solvent was distilled off, the residue was extracted with chloroform and washed with an aqueous citric acid solution and an aqueous sodium hydrogen carbonate solution. The chloroform phase was separated and dried over sodium sulfate to obtain N-Boc-glycylglycylaminoethyl-azobenzene-4-carboxylamide (0.31 g, yield 69%).
Next, the N-Boc-glycylglycylaminoethyl-azobenzene-4-carboxylamide (0.31 g, 0.80 mmol) was dissolved in N, N′-dimethylformamide, and 4N hydrochloric acid- Acetic acid was added in several batches to 50 equivalents and stirred overnight. After distilling off the solvent and acid, the residue was washed with chloroform and water to obtain N-glycylglycylaminoethyl-azobenzene-4-carboxylamide (0.20 g, yield 65%).

The analysis results of the obtained compound by H-NMR, elemental analysis, and electrospray ionization mass spectrometry were as follows.
H-NMR (400 MHz, DMSO-d6) 3.3 (4H, N-CH2CH2-N, overlapping with water peak), 3.62 (2H, s, N-CH2-C = O), 3.79 (2H, d,- N-CH2-C = O), 7.62-7.64 (3H, dd, benzene), 7.92-7.95 (2H, dd, benzene), 7.96 (2H, d, benzene), 8.08 (2H, d, benzene), 8.21 (1H, t, NH), 8.67 (1H, t, NH), 8.78 (1H, t, NH)
Elemental analysis (C19H22N6O3)
Calculated (%) C 59.67, H 5.80, N 21.98
Actual value (%) C 58.26, H, 5.86, N 21.26
Electrospray ionization mass spectrometry
m / z = 404.9 (+ Na ⁺ )

Synthesis Example 3: Synthesis of N-glycylglycylglycylaminoethyl-azobenzene-4-carboxylamide The aminoethyl-benzoxy-carboxylamide (0.70 g, 3.5 mmol) and Boc-glycylglycylglycine (1. 01 g, 3.5 mmol) was stirred overnight in methanol in the presence of condensing agent DMT-MM (1.2 g, 4.3 mmol). After the solvent was distilled off, the residue was extracted with chloroform and washed with an aqueous citric acid solution and an aqueous sodium hydrogen carbonate solution. The chloroform phase was separated and dried over sodium sulfate to obtain N-Boc-glycylglycylglycylaminoethyl-azobenzene-4-carboxylamide (0.82 g, yield 51%).
The obtained N-Boc-glycylglycylglycylaminoethyl-benzoxy-carboxylamide (0.82 g, 1.8 mmol) was dissolved in methanol, catalytic hydrogenation was performed in the presence of Pd / C, and N-Boc- Glycylglycylglycylaminoethylamine was obtained. After removing Pd / C by filtration, azobenzene-4-carboxylic acid (0.40 g, 1.8 mmol) was added, and the mixture was stirred overnight in the presence of a condensing agent DMT-MM (0.59 g, 2.1 mmol). After the solvent was distilled off, the residue was washed with chloroform, aqueous citric acid solution and aqueous sodium hydrogen carbonate solution, recrystallized with methanol, and N-Boc-glycylglycylglycylaminoethyl-azobenzene-4-carboxylamide (0.27 g, Yield 28%).
Subsequently, the N-Boc-glycylglycylglycylaminoethyl-azobenzene-4-carboxylamide (0.067 g, 0.13 mmol) was dissolved in N, N′-dimethylformamide and cooled to −5 ° C. with 4N hydrochloric acid. -Acetic acid was added in several batches to 50 equivalents and stirred overnight. After the solvent and acid were distilled off, the residue was washed with chloroform and water to obtain N-glycylglycylglycylaminoethyl-azobenzene-4-carboxylamide (0.041 g, yield 75%).

The analysis results of the obtained compound by H-NMR, elemental analysis, and electrospray ionization mass spectrometry were as follows.
H-NMR (400 MHz, DMSO-d6) 3.3 (4H, N-CH2CH2-N, overlapping with water peak), 3.72 (2H, s, N-CH2-C = O), 3.87 (2H, d,- N-CH2-C = O), 7.63 (3H, dd, benzene), 7.93 (2H, dd, benzene), 7.96 (2H, d, benzene), 7.97 (1H, t, NH), 8.06 (2H, d , benzene), 8.29 (1H, t, NH), 8.62 (1H, t, NH), 8.73 (1H, t, NH)
Elemental analysis (C21H25N7O4)
Calculated (%) C 57.29, H 5.73, N 22.31
Actual value (%) C 56.36, H, 5.80, N 21.67
Electrospray ionization mass spectrometry
m / z = 462.1 (+ Na ⁺ )

<Manufacture of organic nanotubes>
(Production Example 1)
A dispersion aqueous solution (1.0 mg / ml) of N-glycylaminoethyl-azobenzene-4-carboxylamide obtained in Synthesis Example 1 was adjusted to pH 7.0 to 8.5 using hydrochloric acid and sodium hydroxide, and 100 Heated at 1 ° C. for 1 minute. Thereafter, the mixture was gradually cooled to room temperature to precipitate a solid.
Observation with an electron microscope revealed that the precipitated solid was a nanotube having an inner diameter of 13 to 37 nm, an outer diameter of about 12 nm, and a length of several μm. An electron micrograph of the obtained organic nanotube is shown in FIG.

(Production Example 2)
A dispersion aqueous solution (1.0 mg / ml) of N-glycylglycylaminoethyl-azobenzene-4-carboxylamide obtained in Synthesis Example 2 was adjusted to pH 7.5 using hydrochloric acid and sodium hydroxide, and 100 ° C., 1 Heated for minutes. Thereafter, the mixture was gradually cooled to room temperature to precipitate a solid.
Observation with an electron microscope revealed that the precipitated solid was a nanotube having an inner diameter of about 6 nm, an outer diameter of about 12 nm, and a length of several to several tens of μm. An electron micrograph of the obtained organic nanotube is shown in FIG.

(Production Example 3)
A dispersion aqueous solution (1.0 mg / ml) of N-glycylglycylglycylaminoethyl-azobenzene-4-carboxylamide obtained in Synthesis Example 3 was adjusted to pH 6.0 to 6.5 using hydrochloric acid and sodium hydroxide. And heated at 100 ° C. for 1 minute. Thereafter, the mixture was gradually cooled to room temperature to precipitate a solid.
Observation with an electron microscope revealed that the precipitated solid was a nanotube having an inner diameter of about 13 nm, an outer diameter of about 10 nm, and a length of several to several tens of μm. An electron micrograph of the obtained organic nanotube is shown in FIG.

<Photoisomerization>
(Photoisomerization example 1)
The solid organic nanotube in which N-glycylaminoethyl-azobenzene-4-carboxylamide obtained in Production Example 1 is self-assembled is dispersed in water (3.8 × 10 ⁻⁴ M), and ultraviolet light 365 nm is 4 to 4 nm. Irradiated with visible light of 436 nm for 4 to 30 minutes for 8 minutes.
It is clear from the UV-visible absorption spectrum measurement that the azobenzene moiety reaches the structural isomerization equilibrium from the trans form to the cis form in 4 minutes, and then reaches the structural isomerization equilibrium from the cis form to the trans form in 15 minutes. It became. The obtained ultraviolet-visible absorption spectrum is shown in FIG.

(Photoisomerization example 2)
20 mg of solid organic nanotubes self-assembled with N-glycylaminoethyl-azobenzene-4-carboxylamide obtained in Production Example 1 and 4 g of barium sulfate were mixed in a mortar, and after compression molding, ultraviolet rays of 365 nm were 4-12 Then, irradiation with visible light of 436 nm was performed for 4 to 12 minutes.
Diffuse reflection UV-visible absorption spectrum measurement shows that the azobenzene moiety reaches the structural isomerization equilibrium from the trans form to the cis form in 4 minutes, and then reaches the structural isomerization equilibrium from the cis form to the trans form in 4 minutes. Became clear. The obtained diffuse reflection ultraviolet-visible absorption spectrum is shown in FIG.

<Guest release>
(Guest release example 1)
The solid organic nanotubes self-assembled with N-glycylaminoethyl-azobenzene-4-carboxylamide obtained in Production Example 1 were vacuum-dried overnight. 5 mg of organic nanotubes and 60 mg of carboxyfluorescein as a guest molecule were mixed in water, adjusted to pH 6.3, and stirred overnight. The organic nanotubes were separated by filtration using a membrane filter having a pore size of 200 nm and washed thoroughly with water.
The resulting carboxyfluorescein clathrated organic nanotubes were redispersed in water at pH 5.6 and left for 40 hours. Thereafter, the pH was adjusted to 8.4 by adding sodium hydroxide, and the mixture was further allowed to stand for 80 hours.
Carboxyfluorescein encapsulated in the hollow cylinder space of organic nanotubes is in a quenching state to form a dimer, whereas carboxyfluorescein released into the bulk exists as a monomer and emits intrinsic strong fluorescence. Show. According to the fluorescence spectrum measurement, almost no recovery of the fluorescence intensity derived from the release of carboxyfluorescein was observed between 0 and 40 hours at pH 5.6 (the fluorescence intensity at an arbitrary time is defined as Ft). On the other hand, at pH 8.4, an increase in fluorescence intensity derived from the release of carboxyfluorescein was observed between 0 and 20 hours, and the fluorescence intensity was almost constant until 60 hours thereafter (the fluorescence intensity at an arbitrary time). Ft). Surfactant Triton X-100 is added and the nanotubes are disintegrated, so that all the inclusion carboxyfluorescein is forcibly released into the bulk. The fluorescence intensity at that time is Ftotal, and the calculation formula 100 · Ft / Ftotal is Using, the percent release at any time was calculated. The obtained release rate curve is shown on the left of FIG.

(Guest release example 2)
Using the method described in Guest Release Example 1, similarly, carboxyfluorescein clathrated organic nanotubes were prepared, redispersed in water at pH 5.6, and irradiated with ultraviolet light 365 nm for 0 to 60 minutes. Visible light 436 nm was irradiated for 30 minutes, then adjusted to pH 8.4, and ultraviolet light 365 nm was irradiated for 0 to 60 minutes.
From the fluorescence spectrum measurement, recovery of fluorescence intensity derived from the release of carboxyfluorescein was observed under irradiation with ultraviolet light at pH 5.6 (fluorescence intensity at an arbitrary time is Ft). Further, a significant increase in fluorescence intensity derived from the release of carboxyfluorescein was observed under pH 8.4 and ultraviolet light irradiation (the fluorescence intensity at an arbitrary time is Ft). Surfactant Triton X-100 is added and the nanotubes are disrupted to forcibly release all the inclusion carboxyfluorescein into the bulk. The fluorescence intensity at that time is defined as Ftotal, and the calculation formula 100 · Ft / Ftotal is Using, the percent release at any time was calculated. The obtained release rate curve is shown on the right side of FIG.

  As a result, it was found that the release of carboxyfluorescein from the organic nanotube of the present invention can be controlled by light irradiation, that is, non-contact stimulation. The release was characterized by a faster rate in response to fast photostructural isomerization of the azobenzene sites in the organic nanotubes compared to the left of FIG. 6 where sodium hydroxide needs to be added in the system.

Claims (5)

The following general formula _{H (NHCH 2 CO) n NHC} 2 H 4 NHCO-R
(In the formula, R represents a residue of an aromatic compound having a reversible photocatalytic function selected from azobenzene, spiropyran, leuco dye, coumarin, anthracene, diphenylbutadiene, or stilbene , and n represents an integer of 1 to 3. )
An amide compound represented by: An organic nanotube obtained by self-assembling the compound according to claim 1 . A method for producing an organic nanotube, comprising heating and dissolving the compound according to claim 1 in water and cooling to room temperature. A method for producing a guest inclusion organic nanotube, comprising dispersing the organic nanotube according to claim 2 and a compound serving as a guest in water to include the guest. A method for releasing a guest from an organic nanotube, wherein the guest is released by irradiating the organic nanotube according to claim 2 containing ultraviolet light with ultraviolet rays.