JPH0459930B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a nylon capsule, and more particularly to a nylon capsule having a completely novel structure that reversibly changes membrane permeability in response to subtle changes in pH. The endoplasmic reticulum, which has a membrane that reversibly changes its membrane permeability in response to external stimuli such as changes in external pH, is extremely useful in treatment, diagnosis, and physiological metabolism as an in-vivo reaction model and drug carrier. It is a useful substance for research and practical use in a wide range of fields.
They can also be called a type of artificial cell. In addition, if the membrane opens and closes in response to changes in pH, allowing colored liquid stored in the endoplasmic reticulum to flow out, it can be effectively used as a pH indicator. , measurements in the field of medicine,
It can also be effectively used as an analysis tool. Therefore, there has been a strong desire in the art to develop new such substances. The present invention has been made in view of the current state of the technology, and it is possible to create endoplasmic reticulum and capsules that have extremely excellent PH responsiveness, which has not been known in the past, artificially and without using biological materials. This was done for mass production. Therefore, as a base substance, synthetic polymer substances are suitable for industrial mass production in terms of price, quality stability, and ease of processing. After considering many synthetic polymer materials and considering various aspects, we decided on nylon. From the perspective of normal plastic technology, nylon with high porosity and high moisture absorption is not welcomed, but in the present invention, such porous nylon is suitable as a base. It can be said that this product has opened up new uses for so-called low-quality nylon. After making this nylon capsule, the nylon capsule was dialyzed in a phosphate buffer containing 1,5-naphthalenedisulfonic acid disodium salt as a fluorescent probe to trap the fluorescent probe inside the capsule cavity. When this was then placed in a solution of sodium ditridecyl phosphate in dodecane, the dialkyl compound was
They discovered that the nylon capsule not only filled the pores of the capsule, but also formed a bilayer membrane structure. Next, when this nylon capsule was placed in water with a pH of 2, it was completely unexpected that the fluorescent probe housed inside the capsule permeated to the outside, and then the pH increased.
When I set it to 7, the fluorescent probe stopped passing through.
Furthermore, we obtained a completely new finding that this reaction is reversible. That is, the above-mentioned dialkyl compound becomes a bilayer membrane (forming) compound, and as a result, the nylon membrane formed by filling the pores with this bilayer membrane becomes a kind of biological cell membrane, and a capsule having such a nylon membrane is
They obtained new knowledge that they can be called a type of artificial cell equipped with an ion gate that opens and closes in response to changes in pH. Based on this new knowledge, the present inventors conducted extensive and deep research on nylon as a base, screening for bilayer membrane compounds other than the above-mentioned dialkyl compounds, and finally completed the present invention. This is what I have come to do. That is, the present invention is based on nylon,
It is a nylon capsule surrounded by a nylon membrane made by filling the pores with a specific bilayer membrane compound. Nylon capsules are manufactured by a conventional method by reacting diamines with dibasic acids, or by polymerizing or polycondensing amino acids or lactams, and are produced using 6,6-nylon, 6,10-nylon, 2,
12 - Other suitable uses of nylon. For example, interfacial polymerization involves dissolving the acid chloride of a dibasic acid in an organic solvent that does not mix with water, and adding an alkaline aqueous solution of diamine to this solution to instantaneously form nylon capsules at the interface of both liquid phases. Nylon capsules are manufactured by the method described above or any other suitable method. The size of the capsule can be adjusted freely by changing the size of the diamine alkaline droplets. According to the present invention, the nylon capsule is dialyzed in solutions, such as buffered solutions, of the substance to be contained therein to cause the substance to be contained within the cavity of the capsule. If this is placed in a solution of a bilayer membrane compound dissolved in an organic solvent such as dodecane and left to stand, the desired nylon capsule in which the bilayer membrane compound is filled in the pores of the nylon capsule can be obtained. be. FIG. 1 is a schematic illustration of a nylon capsule according to the present invention obtained in this manner, with a portion thereof being exaggerated and enlarged. The nylon capsule 1 has a nylon capsule membrane 2.
This membrane is porous, with pores 3
The inside and outside are connected through it. This pore 3 contains sodium ditridecyl phosphate.

A bilayer membrane-forming compound 4 represented by the formula is appropriate. A partially enlarged view of this is shown in the circle, and the compound forms a bilayer membrane, and the fluorescent probe 5 trapped in the internal aqueous phase is confined within the capsule.
I never go outside. However, the PH outside the capsule
2.5 to 2, the compound 4 is no longer able to form and maintain a bilayer membrane, and the fluorescent probe 5
flows out to the external aqueous phase as shown by arrow A. Then, this nylon capsule according to the present invention was placed in a quartz cell, and 0.1N HCL and 0.1N NaOH were added.
Alternately change the external PH to 72 using
The transmission coefficient was measured based on the change in emission intensity at 340 nm (excitation at 290 nm) over time, and the results shown in FIG. 2 were obtained. When the temperature is higher than the gel-liquid crystal phase transition temperature Tc of the bilayer membrane, the external PH is 7 as shown in b.
When , the probe hardly passes through, but the external
When the pH was changed to 2, the membrane permeability increased 9-10 times, and when the external pH was returned to neutral, the membrane permeability returned to its original slow state. Such as this due to external PH change
The 10-fold change in membrane permeability could be repeated several times without damaging the bilayer membrane or capsule membrane. On the other hand, as shown in a, capsules not coated with a bilayer membrane allow rapid permeation, and the membrane permeability of the probe does not change even when the external pH changes. In addition, when the temperature is lower than Tc, even if the capsule is coated with a bilayer membrane, the permeation is slow, as shown in c, and there is little difference in membrane permeability even with changes in external pH. I can't see it. In other words, when a nylon capsule coated with a bilayer membrane is exposed to a certain temperature and the external PH changes, the structure of the bilayer membrane compound applied to the pores is reversibly destroyed, and the capsule is The substance contained in the inner envelope permeates to the outside. When the external pH is further changed, the structure of the bilayer membrane compound returns to its original state, and the permeation of substances stops or decreases. In other words, the nylon capsule according to the present invention can be said to be a kind of endoplasmic reticulum, a capsule surrounded by a nylon membrane having a large number of ion gates that open and close in response to pH.
This structure can be said to be extremely similar to living cells. Although the details of this ion gate opening/closing mechanism will require further research, it is estimated as follows. Please refer to Figure 3. Bilayer membrane-forming substance 4 coating the pores 3 of the capsule membrane 2
forms a bilayer membrane below Tc and does not allow the fluorescent probe 5 to pass through (). Even when the temperature rises to above Tc, if the pH of the external aqueous phase is 7, phosphoric acid is in the anion form, so it forms a bilayer film with high barrier ability. Does not allow fluorescent probe 5 to pass through (). However, when the pH decreases, some of the polar groups are neutralized, so that compound 4 is no longer able to form a bilayer membrane, creating a disordered region, which increases the rate of permeation of fluorescent pilobes 5 ( ). and,
This mechanism of action changes reversibly with changes in pH. Nylon capsules coated with bilayer-forming compounds in this way can not only trap fluorescent probes in the aqueous phase within the capsule, but can also trap other substances, and can be used for a variety of purposes. . For example, as mentioned above Measurement of membrane permeability using fluorescent probes or saline; Missile therapy or sustained release microcapsules using anticancer drugs and other various drugs; Fermentation production using enzymes or microorganisms; Production of antibodies and other immune substances using antigens; Physiology using tissues It can be used for various industrial, biological, medical, agricultural, chemical, and pharmaceutical applications. The bilayer membrane-forming compound in the present invention is a metal salt such as sodium or potassium of di-higher alkyl phosphoric acid having 7 to 20 carbon atoms, but dialkali compounds having other than 12 carbon atoms can be advantageously used. For example, sodium salts or potassium salts of diheptyl phosphate, dinonyl phosphate, dioundodecyl phosphate, ditridecyl phosphate, dinonadecyl phosphate, dieicosanyl phosphate, etc. are preferred, but C8-17
Of course, dialkyl compounds can also be used advantageously. As detailed above, the nylon capsule according to the present invention is manufactured through the steps of manufacturing the nylon capsule, encapsulating a substance in the capsule, and applying a bilayer membrane-forming compound to the pores of the nylon membrane. However, since these processes themselves do not require much skill, they are extremely suitable for industrialization and mass production. Furthermore, changes in membrane permeability due to changes in PH are sensitive and reversible, and the long life of nylon capsules allows them to be used for a very long time in various applications. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 1 mmol of 1,10-bis(chlorocarbonyl)
0.03−0.1m mol as decane and crosslinker
Dissolve trymesoil chloride in 100ml of mixed solvent,
The 80 ml was placed in a Petri dish with a diameter of 15 cm. 2 ml of an aqueous solution containing ethylenediamine (0.38M) and NaOH (0.8M) was dropped into the above acid chloride solution using a glass cylinder equipped with a No. 1 stainless steel needle. During this process, the Petri dish was kept in constant vibration. After dropping, remaining acid chloride solution (20ml)
was added and allowed to react for 10 minutes while shaking the Pesilli dish. After the reaction, the solution was decanted and the capsules were washed three times with mixed organic solvent. using this method,
Nylon capsules with a uniform particle size of 2 to 2.5 mm in diameter and 5 to 10 μm in film thickness were obtained. Example 2 The nylon capsule produced in Example 1 was 0.1M
The capsule was thoroughly dialyzed in a saline solution for 3 days to trap the saline inside the capsule. In this way, 10 nylon capsules with saline sealed in the internal space were taken out, and these were added to the dialkyl compound. 10 mg was added to a solution of 1 ml of dodecane while heating to 60°C. Then let it cool to room temperature,
Thereafter, it was left to stand for 1 hour to obtain the desired nylon capsule. Example 3 Using the nylon capsule manufactured in Example 1 (diameter 2 mm, film thickness 1 μm), a fluorescent probe of 1×10 ^-3 M was used. The tube was dialyzed in a 0.01M phosphate buffer containing 0.01M phosphoric acid to encapsulate the fluorescent probe in the inner cavity. This is converted into a bilayer membrane-forming compound. In addition to the dodecane solution, the desired nylon capsules were obtained. Example 4 A PH-responsive nylon capsule containing a fluorescent probe was obtained by repeating the same process as in Example 3 except that sodium ditridecyl phosphate was used as the bilayer membrane compound. Example 5 A nylon capsule containing saline and coated with a bilayer membrane was prepared by repeating the same procedure as in Example 2 except that the following compound was used instead of the dialkyl compound. I got each. By measuring the change in electrical conductivity due to permeation of common salt, it was confirmed that these nylon capsules have excellent reversible PH response.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a nylon capsule according to the present invention, with a portion thereof being exaggerated and enlarged. FIG. 2 illustrates changes in permeability with changes in external PH. FIG. 3 is a schematic diagram illustrating the membrane permeability mechanism of a nylon capsule. 1... Nylon capsule, 4... Bilayer membrane, 5
...Fluorescent probe.

Claims (1)

[Claims] 1. A compound represented by the following formula in the pores of the nylon capsule membrane. (In the formula, n represents an integer from 7 to 20 excluding 12,
M represents a metal atom. ) A nylon capsule that responds to pH.