JP2022040937A - Polyvalent fluorine-based surfactant - Google Patents

Abstract

To provide a fluorine-based surfactant that quickly adsorbs to an interface between fluorine oil and water to reduce the interfacial tension of both, thereby stabilizing the droplets.SOLUTION: A fluorine-based surfactant is composed of one compound selected from the group consisting of following formulae (I)-(III): [A]a-X-B-X-D (I), [A]a-X-B-X-[A]b (II), and [A]c-X (III) [where A is a fluorine carbide group, B is oligo(ethylene glycol), D is NH2, NH3, N(CH3) H, N(CH3) H2, N(CH3)2, or N(CH3)3, a, b, and c each independently represent a positive integer, and X is a covalent bond or a linking group, provided that a plurality of Xs included in the compound may be the same or different].SELECTED DRAWING: Figure 5

Description

The present invention relates to a fluorine-based surfactant, a droplet of a W / O emulsion containing the surfactant, and a method of using the same.

A method of culturing microorganisms inside droplets (droplets) by treating a Water-in-oil emulsion in which water is dispersed in oil as a minute aqueous reaction field is attracting attention as a high-throughput screening technique. By mixing fluorinated oil with a large amount of dissolved oxygen and water using a micromixer, it is possible to prepare tens of thousands of homogeneous droplets of several tens of microns per minute, and even in one of the droplets. Can be cultivated with aerobic microorganisms. Since the volume of the droplet is about one millionth of that of a well of a general microplate, noise due to impurities is reduced and analysis accuracy is improved.

A fluorosurfactant is used to stabilize the droplet in the fluorooil. Fluorine-based surfactants have both hydrophilic groups and fluorine groups in the same molecular skeleton, and when two liquids of water and fluorine oil are mixed, they are oriented at the interface between the two to reduce the interfacial tension. Let me. Currently, as a fluorine-based surfactant for stabilizing droplets, triblock copolymers composed of perfluoropolyether (PFPE) and polyethylene glycol (PEG) are used (Patent Documents 1 and 2). This reduces the interfacial tension by orienting at the interface between water and fluorine oil, and the polymer chain three-dimensionally protects the interface and stabilizes the droplet. However, although the block copolymer synthesized by the ligation reaction between two kinds of polymers is chemically stable, it is difficult to further modify the structure. Therefore, it is possible to control the hydrophilic / hydrophobic balance and introduce a functional functional group. Have difficulty.

Further, for the purpose of expanding the molecular structure, in Non-Patent Document 1, instead of PEG, a triblock copolymer in which a polyglycerol group capable of chemically modifying a side chain is introduced is synthesized, and in Non-Patent Documents 2 and 3, , Polymers in which triol or dendrimer type polyhydric alcohol is introduced at the end of PFPE have been reported.

When a fluorine oil and water are rapidly mixed using a microreactor, the fluorine-based surfactant is required to be rapidly adsorbed on the interface to stabilize water droplets (see Non-Patent Document 4). However, since the currently used fluorosurfactants have a high molecular weight of 10,000 or more, rapid adsorption to the interface cannot be expected, and an excess amount of the surfactant is used to accelerate the interfacial adsorption. It makes up for the slowness of the problem and is not economical. In addition, there is a problem that the droplet becomes unstable due to heating and the small molecule compound inside flows out.

International release 2017/203280 U.S. Pat. No. 4,948,761

Lab on a Chip (2016) Vol. 16, p. 65-69 ACS Nano (2014) Vol. 8, p. 3913-3920 Nature Communications (2019) Vol. 10, p. 4546. Langmuir (2009) Vol. 25, p. 6088-6093

Droplets of W / O emulsions containing fluorine oil and aqueous liquids are nontoxic to cells and are not only used as microbial culture sites, but also for enzyme activity testing, DNA / RNA replication amplification / synthesis, RNA expression, and protein synthesis. It is expected to have a wide range of applications such as crystallization, DNA / RNA cleavage / binding / dissociation, synthesis of inorganic materials such as nanoparticles, and specific reaction fields for organic synthesis.
However, the limited types of fluorosurfactants that can be used hinder their application. Since the conventional high-molecular-weight fluorine-based surfactant has a slow interfacial adsorption rate, it is necessary to dissolve an excessive amount in fluorine oil in order to rapidly reduce the interfacial tension and stabilize the droplet. The stability of the dropped drops was also not sufficient.
The present invention has been made in view of such circumstances, and has a high interfacial adsorption rate, rapidly adsorbs to the interface between fluorine oil and water, significantly reduces the interfacial tension between the two, and stabilizes the droplet. It is an object of the present invention to provide a fluorine-based surfactant that can be used.

As a result of diligent studies to solve the above problems, the present inventors did not connect the low molecular weight high molecular weight PFPE and PEG, but sequentially the low molecular weight fluorine carbide and the polyfunctional oligoethylene glycol. We have developed a fluorine-based surfactant that can freely control the molecular weight distribution and the number of fluorine chains by the ligation reaction, and found that this not only actually forms a droplet but also stabilizes it for a long period of time, and completed the present invention. I let you.

ここで、Ｒ_fは、炭化水素基（－ＣＨ_２－）、カルボニル基(－Ｃ＝Ｏ)、アミノ基（－ＮＨ－）、またはエーテル基（－Ｏ－）の少なくとも一つを含む連結基を内部に含んでいてもよい、炭素数が４～１２の炭化フッ素基であり、ｎは１～２０の付加モル数である。
（４） 前記式（ＩＩ）の化合物が下記式（Ｂ）で表される、上記（１）または（２）に記載のフッ素系界面活性剤。

ここで、Ｒ_fは、炭化水素基（－ＣＨ_２－）、カルボニル基(－Ｃ＝Ｏ)、アミノ基（－ＮＨ－）、またはエーテル基（－Ｏ－）の少なくとも一つを含む連結基を内部に含んでいてもよい、炭素数が４～１２の炭化フッ素基であり、複数のＲ_fは、それぞれ同じでも異なってもよく、ｎは１～２０の付加モル数である。
（５） 前記式（ＩＩＩ）の化合物が下記式（Ｃ）で表される、上記（１）または（２）に記載のフッ素系界面活性剤。

ここで、Ｒ_fは、炭化水素基（－ＣＨ_２－）、カルボニル基(－Ｃ＝Ｏ)、アミノ基（－ＮＨ－）、またはエーテル基（－Ｏ－）の少なくとも一つを含む連結基を内部に含んでいてもよい、炭素数が４～１２の炭化フッ素基であり、複数のＲ_fは、それぞれ同じでも異なってもよい。
（６） 前記式（ＩＩ）の化合物が下記式（Ｄ）で表される、上記（１）または（２）に記載のフッ素系界面活性剤。

ここで、Ｒ_fは、炭化水素基（－ＣＨ_２－）、カルボニル基(－Ｃ＝Ｏ)、アミノ基（－ＮＨ－）、またはエーテル基（－Ｏ－）を含む連結基を内部に含んでいてもよい、炭素数が４～１２の炭化フッ素基であり、Ｘは、カルボニル基(－Ｃ＝Ｏ)、アミノ基（－ＮＨ－）、エーテル基（－Ｏ－）、フェニレン基（－Ｃ_６Ｈ_４－）、または芳香族アミン（－ＮＣ_６Ｈ_４－）の少なくとも一つを内部に含んでいてもよい、鎖式炭化水素基または芳香族炭化水素基から選択される連結基であり、複数のＲ_fおよびＸは、それぞれ同じでも異なってもよく、ｎは１～２０の付加モル数である。
また、本発明は、以下（７）のドロプレット、および（８）のドロプレットの使用方法に係るものである。
（７） 上記（１）ないし（６）のいずれかに記載のフッ素系界面活性剤、フッ素油、および親水性液体を含む、Ｗ／Ｏエマルジョンのドロプレット。
（８） 上記（７）に記載のドロプレットを、微生物の培養場、酵素活性試験、ＤＮＡ/ＲＮＡの複写増幅・合成、ＲＮＡの発現、タンパク質の合成/結晶化、ＤＮＡ/ＲＮＡの切断・結合・解離、ナノ粒子等の無機材料の合成、または有機合成の特異反応場として使用する、ドロプレットの使用方法。 The present invention relates to the following fluorine-based surfactants (1) to (6).
(1) [A] _a -X-B-X-D (I),
[A] _a -X-B-X- [A] _b (II), and [A] _c -X (III)
A fluorine-based surfactant comprising one compound selected from the group consisting of the formulas (I) to (III).
Here, in the formula, A is a fluorine carbide group, B is an oligoethylene glycol, D is NH ₂ , NH ₃ , N (CH ₃ ) H, N (CH ₃ ) H ₂ , N (CH ₃ ) ₂ , or N (CH ₃ ) ₃ , where a, b, and c are independent positive integers, where X is a covalent bond or linking group, and in compounds containing multiple Xs, each is the same but different. May be good.
(2) The positive integers a, b and c are independently 1 to 6, and X is a carbonyl group (-C = O), an amino group (-NH-) and an ether group (-O-). ), A phenylene group (-C ₆ H _4- ), or an aromatic amine (-NC ₆ H _4- ) may be contained therein from a chain hydrocarbon group or an aromatic hydrocarbon group. The fluorine-based surfactant according to (1) above, which is the linking group to be selected.
(3) The fluorine-based surfactant according to the above (1) or (2), wherein the compound of the formula (I) is represented by the following formula (A).

Here, R _f is a linking group containing at least one of a hydrocarbon group (-CH _2- ), a carbonyl group (-C = O), an amino group (-NH-), or an ether group (-O-). Is a hydrocarbon group having 4 to 12 carbon atoms, and n is an additional molar number of 1 to 20.
(4) The fluorine-based surfactant according to the above (1) or (2), wherein the compound of the formula (II) is represented by the following formula (B).

Here, R _f is a linking group containing at least one of a hydrocarbon group (-CH _2- ), a carbonyl group (-C = O), an amino group (-NH-), or an ether group (-O-). Is a hydrocarbon group having 4 to 12 carbon atoms, and the plurality of R _fs may be the same or different, and n is an additional molar number of 1 to 20.
(5) The fluorine-based surfactant according to the above (1) or (2), wherein the compound of the formula (III) is represented by the following formula (C).

Here, R _f is a linking group containing at least one of a hydrocarbon group (-CH _2- ), a carbonyl group (-C = O), an amino group (-NH-), or an ether group (-O-). Is a hydrocarbon group having 4 to 12 carbon atoms, and the plurality of R _fs may be the same or different.
(6) The fluorine-based surfactant according to (1) or (2) above, wherein the compound of the formula (II) is represented by the following formula (D).

Here, R _f contains a linking group containing a hydrocarbon group (-CH _2- ), a carbonyl group (-C = O), an amino group (-NH-), or an ether group (-O-). It may be a hydrocarbon group having 4 to 12 carbon atoms, and X is a carbonyl group (-C = O), an amino group (-NH-), an ether group (-O-), or a phenylene group (-). A linking group selected from chain hydrocarbon groups or aromatic hydrocarbon groups that may contain at least one of C ₆ H _4- ) or an aromatic amine (-NC ₆ H _4- ). There, the plurality of R _fs and Xs may be the same or different, and n is an additional molar number of 1 to 20.
The present invention also relates to the following droplet (7) and the method of using the droplet (8).
(7) A droplet of a W / O emulsion containing the fluorine-based surfactant according to any one of (1) to (6) above, a fluorine oil, and a hydrophilic liquid.
(8) The droplet described in (7) above can be used in a microbial culture field, enzyme activity test, DNA / RNA replication amplification / synthesis, RNA expression, protein synthesis / crystallization, DNA / RNA cleavage / binding. A method of using droplets, which is used as a specific reaction field for dissociation, synthesis of inorganic materials such as nanoparticles, or organic synthesis.

According to the present invention, it is possible to adsorb to the fluorine oil / water interface more quickly than the conventional polymer-based fluorine-based surfactant, and the amount of the fluorine-based surfactant used for stabilizing the droplet can be reduced. , Can be reduced to about 1/3.
Further, by controlling the number of carbonized fluorine introduced into the polyfunctional oligoethylene glycol, it is possible to produce a fluorine-based surfactant having different valences, and it is possible to systematically change various physical properties of the fluorine-based surfactant.

The ability of the fluorine-based surfactant to reduce the interfacial tension in the test of Example 5 is shown. The interfacial adsorption rate of the fluorine-based surfactant in the test of Example 6 is shown. A photograph of the appearance of the droplet produced in Example 7. The photograph which shows the stability of the droplet produced in Example 7. Photograph of E. coli culture in the droplet of Example 8.

The fluorine-based surfactant of the present invention is
[A] _a -X-B-X-D (I),
[A] _a -X-B-X- [A] _b (II), and [A] _c -X (III)
It consists of one compound selected from the group consisting of the formulas (I) to (III).
In formulas (I) to (III), A is a fluorine carbide group, B is an oligoethylene glycol, D is NH ₂ , NH ₃ , N (CH ₃ ) H, N (CH ₃ ) H ₂ , N (CH ₃ ). ) ₂ or N (CH ₃ ) ₃ , where a, b, and c are independent positive integers, where X is a covalent bond or linking group, and in compounds containing multiple Xs, respectively. It may be the same or different.

The positive integers a, b and c relate to the number of fluorine carbide groups A in one molecule, and 1 to 6 are preferable independently. Further, the fluorine carbide group A to be introduced is preferably a monovalent to 12-valent polyvalent fluorine-based surfactant, and more preferably a monovalent to hexavalent polyvalent.
When X is a linking group, X is a carbonyl group (-C = O), an amino group (-NH-), an ether group (-O-), a phenylene group (-C _{6H 4-} ), or A linking group selected from chain hydrocarbon groups or aromatic hydrocarbon groups, which may contain at least one of aromatic amines ( _-NC 6H _4- ). Here, the number of carbon atoms of the chain hydrocarbon group or the aromatic hydrocarbon group is preferably 1 to 40, more preferably 1 to 20.
The molecular weight of the fluorine-based surfactant is preferably 10,000 or less, more preferably 8,000 or less.

The fluorine-based surfactant according to one aspect of the present invention has a chemical structure derived from fluorine carbide having a carboxyl group or an amino group and polyfunctional oligoethylene glycol, and the two are linked by an amide bond or the like. As such a fluorine-based surfactant, a fluorine-based surfactant represented by the following formula (A) can be exemplified.
In the fluorine-based surfactant represented by the formula (A), one carbonized fluorine chain is linked to one oligoethylene glycol by an amide bond or the like. Here, R _f is a linking group containing at least one of a hydrocarbon group (-CH _2- ), a carbonyl group (-C = O), an amino group (-NH-), or an ether group (-O-). It is a hydrocarbon group having 4 to 12 carbon atoms which may be contained therein, and n is an additional molar number of 1 to 20. When R _f contains a hydrocarbon group (-CH _2- ), the number of carbon atoms in the hydrocarbon is preferably 1 to 10.

Further, the fluorine-based surfactant of another aspect of the present invention has a chemical structure in which two fluorine carbide chains are linked to one oligoethylene glycol by an amide bond or the like. As such a fluorine-based surfactant, a fluorine-based surfactant represented by the following formula (B) can be exemplified.
Here, R _f is a linking group containing at least one of a hydrocarbon group (-CH _2- ), a carbonyl group (-C = O), an amino group (-NH-), or an ether group (-O-). It is a hydrocarbon group having 4 to 12 carbon atoms which may be contained therein, and n is an additional molar number of 1 to 20. When R _f contains a hydrocarbon group (-CH _2- ), the number of carbon atoms in the hydrocarbon is preferably 1 to 10.

Further, the fluorine-based surfactant of another aspect of the present invention has a chemical structure in which three fluorine carbide groups are linked to one benzene ring by an amide bond or the like. As such a fluorine-based surfactant, a fluorine-based surfactant represented by the following formula (C) can be exemplified.
Here, R _f is a linking group containing at least one of a hydrocarbon group (-CH _2- ), a carbonyl group (-C = O), an amino group (-NH-), or an ether group (-O-). It is a hydrocarbon group having 4 to 12 carbon atoms which may be contained therein, and n is an additional molar number of 1 to 20. When R _f contains a hydrocarbon group (-CH _2- ), the number of carbon atoms in the hydrocarbon is preferably 1 to 10.

Further, the fluorine-based surfactant of another aspect of the present invention has a chemical structure in which four fluorine carbide chains are linked to one hydrophilic group by an amide bond or the like. As such a fluorine-based surfactant, a fluorine-based surfactant represented by the following formula (D) can be exemplified.
Here, R _f contains a linking group containing a hydrocarbon group (-CH _2- ), a carbonyl group (-C = O), an amino group (-NH-), or an ether group (-O-). It may be a hydrocarbon group having 4 to 12 carbon atoms, and X is a carbonyl group (-C = O), an amino group (-NH-), an ether group (-O-), and a phenylene group (-C). A linking group selected from chain hydrocarbon groups or aromatic hydrocarbon groups that may contain at least one of ₆ H _4- ) or an aromatic amine (-NC ₆ H _4- ). , The plurality of R _fs and Xs may be the same or different, respectively, and n is an additional molar number of 1 to 20. The carbon number of the chain hydrocarbon group or the aromatic hydrocarbon group of the linking group is preferably 1 to 40, more preferably 1 to 20.

As a specific compound of the fluorine-based surfactant represented by the formula (A), L1 of the following formula 5 can be exemplified.

As a specific compound of the fluorine-based surfactant represented by the formula (B), L2 of the following formula 6 can be exemplified.

As a specific compound of the fluorine-based surfactant represented by the formula (D), L4 of the following formula 7 can be exemplified.

The fluorine-based surfactant of the present invention can be used to produce a droplet of a W / O emulsion containing a fluorine oil and a hydrophilic liquid. The droplet of the present invention has a diameter of several tens of μm, and either the fluorine oil containing the fluorine-based surfactant of the present invention or the hydrophilic liquid containing the fluorine-based surfactant of the present invention is hydrophilic. It is obtained by mixing with a liquid or fluorine oil with a micromixer and is stable for at least one week. The diameter of the droplet of the present invention is preferably 1 to 500 μm.

Examples of the fluorine oil of the present invention include, but are not limited to, NOVEC7500, FC-40, FC-77, or one or a mixture of two or more thereof. Mineral oil can also be used as an oil other than fluorine oil.
The structure of the micromixer is not particularly limited, but one having a flow path of several hundred microns or less, preferably several tens of microns or less can be used. The hydrophilic liquid may be a pure substance or a mixture.

Further, the droplet of the present invention may contain other components as needed. As such other components, water-soluble or amphipathic substances can be contained, and examples thereof include lower alcohols, inorganic salts, organic salts, acids, bases, and surfactants. Further, when the droplet of the present invention is used as a chemical reaction field, it is possible to contain a catalyst, an enzyme, various metal reagents and the like necessary for the chemical reaction.

The droplet of the present invention can be used for microbial culture sites, enzyme activity tests, DNA / RNA replication amplification / synthesis, RNA expression, protein synthesis / crystallization, DNA / RNA cleavage / binding / dissociation, nanoparticles, etc. It can be used for synthesis of inorganic materials, specific reaction fields for organic synthesis, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention can be appropriately modified as long as it does not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limiting by the specific examples shown below.

(Example 1: Synthesis of L1)
2H, 2H, 3H, 3H-heptadecafluoroundecanoic acid 295 mg (0.60 mmol), DIC 76 mg (0.60 mmol) and DMAP 30 mg (0.24 mmol) were dissolved in 18 mL of tetrahydrofuran and stirred at room temperature for 20 minutes. This mixture was added dropwise to 133 mg (0.60 mmol) of diethylene glycol bis (3-aminopropyl) ether using a dropping funnel over 30 minutes with stirring, and the mixture was stirred at room temperature for 18 hours. After removing the solvent, the crude product was washed with diethyl ether. Then, it was purified by silica gel column chromatography (chloroform: methanol = 1: 1) to obtain L1 in a yield of 159 mg (yield 38%).
^{1 1} H-NMR (400 MHz, CDCl ₃ , room temperature.) δ (ppm): 5.30 (s, 1H, NH), 3.65-3.56 (m, 12H, CH2), 3.51-3. 45 (q, 4H, CH2, J = 8.0 Hz), 2.82 (p, 2H, NH2, J = 6.0 Hz), 2.45 (m, 4H, CH2), 1.79-1 .72 (m, 2H, CH2)
¹⁹ F-NMR (377 MHz, CDCl ₃ , room temperature) δ (ppm): 126.1,123.5,121.9,121.7,121.6,114.6,80.7
IR (ATR): 3600-3100,1645,1552cm ^-1
MALDI-TOF MS: m / z = 694.9 (Calcd. 695.2)

(Example 2: Synthesis of L2)
2H, 2H, 3H, 3H-heptadecafluoroundecanoic acid 483 mg (0.98 mmol), EDC 187 mg (0.97 mmol) and DMAP 38 mg (0.31 mmol) were dissolved in 8 mL of dimethylformamide and stirred at room temperature for 1 hour. 91 mg (0.41 mmol) of diethylene glycol bis (3-aminopropyl) ether was added thereto, and the mixture was stirred at room temperature for 24 hours. After removing the solvent, 30 mL of a mixed solvent of ethyl acetate / hexane (= 9/1) was added, and the mixture was washed 3 times with a saturated aqueous sodium chloride solution (30 mL). The organic phase was dried over magnesium sulfate, the solvent was removed, and the product was purified by silica gel column chromatography (chloroform: methanol = 19: 1) to obtain L2 in a yield of 430 mg (yield 90%).
^{1 1} H-NMR (400 MHz, CDCl ₃ , room temperature) δ (ppm): 6.46 (s, 2H, NH), 3.66-3.56 (m, 2H, CH2), 3.41-3.36 (Q, 4H, CH2, J = 6.7 Hz), 2.45 (m, 8H, CH2), 1.81-1.75 (m, 4H, CH2)
¹⁹ F-NMR (377 MHz, CDCl ₃ , room temperature) δ (ppm): 126.1, 123.5, 122.7, 121.9, 121.7, 114.7, 80.8
IR (ATR): 1639,1551cm ^-1
MALDI-TOF MS: m / z = 1169.6 (Calcd.1169.2)

(Example 3: Synthesis of L4)
1,2-bis (2-aminophenoxy) ethane-N, N, N', N'-tetraacetic acid tetrasodium 250 mg (0.89 mmol), 1H, 1H-undecafluorohexylamine 1.6 mL (8.9 mmol) ), EDC 690 mg (0.79 mmol) and DMAP 11 mg (0.1 mmol) were dissolved in 5 mL of dimethylformamide and stirred at 60 ° C. for 3 days. 30 mL of ethyl acetate was added, the mixture was washed with dilute hydrochloric acid (10 mL) and water (20 mL), and the organic phase was dried over magnesium sulfate. After removing the solvent, purification was performed by silica gel column chromatography (dichloromethane: methanol = 19: 1) to obtain L4 in a yield of 379 mg (yield 27%).
^{1 1} H-NMR (400 MHz, CDCl ₃ , room temperature) δ (ppm): 7.10 (4H, ArH) 6.93 (4H, ArH), 4.33 (s, 4H), 3.75 (s, 8H) , CH2), 2.88 (s, 4H, CH2)
¹⁹ F-NMR (377 MHz, CDCl ₃ , room temperature) δ (ppm): -80.96, -118.5, -123.0, -123.8, -126.5
MALDI-TOF MS: m / z = 1600.9 (Calcd.1601.2)

表１に示すように、バレンシーを変えたＬ１、Ｌ２、Ｌ４はフッ素油に対して異なる溶解性を示し、使用できる溶媒の種類を拡張できることがわかった。 (Example 4: Comparison of solubility)
The solubility of the synthesized L1, L2, and L4 in various oils was compared. The results are shown in Table 1.

As shown in Table 1, it was found that L1, L2, and L4 having different valency showed different solubility in fluorine oil, and the types of solvents that could be used could be expanded.

(Example 5: Evaluation of surface activity)
In a vial, L1 was dissolved in NOVEC 7500 to various concentrations. The interfacial tension lowering ability of L1 with respect to water / NOVEC7500 was measured using an interfacial tension measuring device (manufactured by Kyowa Interface Science Co., Ltd., product name "Drop Master DM500") in which fluorine oil of each concentration was dissolved and dropped.
As shown in FIG. 1, L1 (▲ in FIG. 1) reduced the interfacial tension of water / NOVEC7500. In addition, the critical micelle concentration (CMC) was determined from the concentration at which the surface tension becomes a constant value in the graph of FIG.
The interfacial tension of L2 was measured by the same method. The result is shown in FIG. As shown in FIG. 1, L2 (● in FIG. 1) exhibited an interfacial tension lowering ability similar to L1 although the solubility in NOVEC7500 decreased and a precipitate was formed. Table 2 shows the critical micelle concentrations of L1 and L2 and the surface tension (γ _CMC ) at this time. For comparison, the measurement results using the conventional product (■ in FIG. 1) are also shown in the table.

表２に示すように、Ｌ１とＬ２のＣＭＣは同等であることがわかった。従来品よりはＣＭＣは１桁高いものの、その界面張力低下能は従来品と同程度であり優れた界面活性を発揮することがわかった。

As shown in Table 2, the CMCs of L1 and L2 were found to be equivalent. Although the CMC is an order of magnitude higher than that of the conventional product, it has been found that its ability to reduce the interfacial tension is about the same as that of the conventional product and exhibits excellent surface activity.

(Example 6: Comparison of interfacial adsorption rates)
L1 and L2 were dissolved in NOVEC7500 so as to have a concentration of 5 mg / ml (about 0.5 wt%), and the measurement result of the adsorption rate of the pendant drop is shown in FIG. For comparison, the measurement results using the conventional product (0.5 wt%) are also shown in the figure.
As a result, L1 changed from 4.3 mN / m to 3.0 mN / m in about 3 minutes, L2 changed from 4.6 mN / m to 3.0 mNm in about 4 minutes, and the conventional product changed to 8.2 mN / m in about 9 minutes. It decreased from m to 3.3 mN / m, and the interfacial tension value became constant. That is, it was clarified that the low molecular weights L1 and L2 were adsorbed to the interface more quickly than the conventional products, and the interfacial adsorption rate increased 2-3 times.

(Example 7: Preparation of droplet by micromixer)
Pure water was placed in a water reservoir of a microchip, and Novec7500 in which various surfactants were dispersed in an oil reservoir was placed, and set in a droplet making device On-chip Droplet Generator (On-Chip Biotechnology Co., Ltd.). After that, the valve was opened and the sample pressure and the oil pressure were both flowed at 20 kPa to prepare a droplet. FIG. 3 shows a photograph of the appearance of a droplet prepared by a micromixer using Novec 7500 solutions of L1 and L2 adjusted to concentrations below and above CMC (0.2 mg / ml and 5 mg / ml).
As a result, at concentrations below CMC (0.2 mg / ml), the droplets merged into large droplets immediately after formation with any surfactant, whereas at concentrations above CMC (5 mg / ml), the droplets eventually became large. It was found that even with the above-mentioned surfactant, uniform fine droplets could be produced at least immediately after the formation. In L2, coalescence gradually progressed after formation, whereas in L1, even if droplets increased and aggregation occurred, coalescence did not occur and was stable.

The time course of the shape of the droplet prepared using the L1 / Novec 7500 solution (5 mg / ml) was observed by phase difference observation with an optical microscope. The results are shown in FIG. Droplets were found to be stable for at least 3 days. That is, it was clarified that L1 can produce a stable droplet while being a small molecule fluorine-based surfactant.

(Example 8: Microbial culture in a droplet)
Escherichia coli (E. coli K12 strain) was used for culturing microorganisms in the droplet. In the experiment, Escherichia coli that had been precultured (OD ₆₀₀ = 0.9) was diluted 1/3 times using LB medium. Put the Escherichia coli sample solution prepared as described above in the water reservoir of the microchip, and put the L1 / Novec 7500 solution (5 mg / ml) in the oil reservoir, and set it in the droplet making device On-chip Droplet Generator (Onchip Biotechnology Co., Ltd.). did. After that, the valve was opened and the sample pressure was 25 kPa and the oil pressure was 27 kPa to prepare a droplet containing Escherichia coli.

The appearance of the E. coli-encapsulated droplet prepared by the micromixer is shown in FIG. 5 (immediately after encapsulation). At this time, an average of about 6.7 ± 2.0 E. coli was encapsulated in one droplet (see the enlarged photograph on the right in FIG. 5 (immediately after encapsulation), E. coli looks like spots). The prepared E. coli-encapsulated droplet was collected in a 1.5 mL microtube and statically cultured at 37 ° C. for 1 day. The appearance of the E. coli-encapsulated droplet after 1 day is also shown in FIG. 5 (1 day later).
The average number of Escherichia coli inside the droplet after 1 day was about 20.2 ± 10.5 (see the enlarged photograph on the right in Fig. 5 (1 day later)), and it was found that the number of E. coli was growing compared to the number of cells immediately after encapsulation. It could be confirmed. As described above, it was confirmed that microbial culture is possible in the droplet prepared in L1.

The fluorine-based surfactant of the present invention exhibits excellent surface activity due to its high adsorption rate to the interface. In particular, since droplets can be produced by a micromixer, microbial culture, enzyme activity test, DNA / RNA replication amplification / synthesis, RNA expression, protein synthesis / crystallization, DNA / RNA cleavage / binding / dissociation. It is expected to be used for the synthesis of inorganic materials such as nanoparticles and the specific reaction field of organic synthesis.

Claims (8)

[A] _a -X-B-X-D (I),
[A] _a -X-B-X- [A] _b (II), and [A] _c -X (III)
A fluorine-based surfactant comprising one compound selected from the group consisting of the formulas (I) to (III).
Here, in the formula, A is a fluorine carbide group, B is an oligoethylene glycol, D is NH ₂ , NH ₃ , N (CH ₃ ) H, N (CH ₃ ) H ₂ , N (CH ₃ ) ₂ , or N (CH ₃ ) ₃ , where a, b, and c are independent positive integers, where X is a covalent bond or linking group, and in compounds containing multiple Xs, each is the same but different. May be good. The positive integers a, b and c are independently 1 to 6, respectively, and X is a carbonyl group (-C = O), an amino group (-NH-), an ether group (-O-), and a phenylene. Selected from chain hydrocarbon groups or aromatic hydrocarbon groups which may contain at least one group (-C ₆ H _4- ) or aromatic amine (-NC ₆ H _4- ) internally. The fluorine-based surfactant according to claim 1, which is a linking group. The fluorine-based surfactant according to claim 1 or 2, wherein the compound of the formula (I) is represented by the following formula (A).

Here, R _f is a linking group containing at least one of a hydrocarbon group (-CH _2- ), a carbonyl group (-C = O), an amino group (-NH-), or an ether group (-O-). Is a hydrocarbon group having 4 to 12 carbon atoms, and n is an additional molar number of 1 to 20. The fluorine-based surfactant according to claim 1 or 2, wherein the compound of the formula (II) is represented by the following formula (B).

Here, R _f is a linking group containing at least one of a hydrocarbon group (-CH _2- ), a carbonyl group (-C = O), an amino group (-NH-), or an ether group (-O-). Is a hydrocarbon group having 4 to 12 carbon atoms, and the plurality of R _fs may be the same or different, and n is an additional molar number of 1 to 20. The fluorine-based surfactant according to claim 1 or 2, wherein the compound of the formula (III) is represented by the following formula (C).

Here, R _f is a linking group containing at least one of a hydrocarbon group (-CH _2- ), a carbonyl group (-C = O), an amino group (-NH-), or an ether group (-O-). Is a hydrocarbon group having 4 to 12 carbon atoms, and the plurality of R _fs may be the same or different. The fluorine-based surfactant according to claim 1 or 2, wherein the compound of the formula (II) is represented by the following formula (D).

Here, R _f contains a linking group containing a hydrocarbon group (-CH _2- ), a carbonyl group (-C = O), an amino group (-NH-), or an ether group (-O-). It may be a hydrocarbon group having 4 to 12 carbon atoms, and X is a carbonyl group (-C = O), an amino group (-NH-), an ether group (-O-), or a phenylene group (-). A linking group selected from chain hydrocarbon groups or aromatic hydrocarbon groups that may contain at least one of C ₆ H _4- ) or an aromatic amine (-NC ₆ H _4- ). There, the plurality of R _fs and Xs may be the same or different, and n is an additional molar number of 1 to 20. A droplet of a W / O emulsion comprising the fluorine-based surfactant according to any one of claims 1 to 6, a fluorine oil, and a hydrophilic liquid. The droplet according to claim 7 can be used in a microbial culture field, enzyme activity test, DNA / RNA replication amplification / synthesis, RNA expression, protein synthesis / crystallization, DNA / RNA cleavage / binding / dissociation, nanoparticles. A method of using droplets, which is used as a specific reaction field for the synthesis of inorganic materials such as RNA or organic synthesis.

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