JP2009209215A - Stimulation change responsible material and stimulation change responsible object using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stimulation change responsible material capable of changing a color tone in a single particle, and capable of developing clear color with high contrast. <P>SOLUTION: This material includes a fine particle, dispersed in a dispersion medium, capable of causing a reversible volume change due to the stimulation change. The fine particle supports fluorescent dyes that act as a donor and as an acceptor upon a fluorescence resonance energy transfer, wherein a fluorescence spectrum of the donor and an excitation spectrum of the acceptor have an overlap. The fine particle supports two or more sorts of the fluorescent dyes to become the donor or the acceptor, and in a group of at least two fluorescent dyes, the fluorescence spectrum and the excitation spectrum may have the overlap at a different wavelength range. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a change-responsive material whose fluorescent color changes in response to a change in a stimulus such as temperature, and a change responder using this material.

Stimulus-responsive gels that change volume reversibly in response to changes in stimuli such as temperature, light, current, electric field, ph degree (hereinafter collectively referred to as “temperature, etc.”) are known. A technique for changing the color tone or the like using such a stimulus-responsive gel is applied to display materials and light-modulating materials (see, for example, Patent Documents 4 to 4).
JP 61-148423 A JP-A 61-148824 JP-A-11-228850 JP 2003-147210 A

However, in these methods, since the reflected light from the pigment is controlled by making the gel particles cloudy, there is a problem that the contrast becomes low.
The present invention has been made in view of the above problems, and a change response capable of changing the color tone with a single particle and capable of vivid coloring with high contrast with respect to the background by using fluorescence. An object is to provide a sex change material and a stimulus change responder using the same.

As a result of intensive studies by the inventors of the present invention in order to solve the above-mentioned problems, it has been conceived that the object of the present invention can be achieved by using fluorescence resonance energy transfer (FRET).
Specifically, in the stimulus change responsive material in which the fluorescent color changes due to a stimulus change, the invention according to claim 1 disperses fine particles that cause a volume change reversibly due to the stimulus change in the dispersion medium, This fine particle is configured to carry a fluorescent dye serving as a donor and an acceptor fluorescent dye in fluorescence resonance energy transfer, and the fluorescent dye having an overlap in the excitation spectrum of the donor and the acceptor. .

  In the fluorescence resonance energy transfer, when there is an overlap between the fluorescence spectrum of the donor molecule and the excitation spectrum of the acceptor molecule, if the distance between these molecules is below a certain level, the energy is transferred to the acceptor when the donor is excited. This is a phenomenon in which the acceptor molecule is excited. It is known that the fluorescence resonance energy transfer efficiency increases rapidly as the intermolecular distance decreases. For this reason, the stimulus change responsive material having the above structure is swollen in water at a low temperature, for example, and the intermolecular distance becomes large, and light emission from the donor has priority, but when the temperature is increased and the phase transition temperature is exceeded. The cross-linked polymer gel contracts, the intermolecular distance decreases, and the luminescence emitted from the acceptor increases. Thus, by changing the swelling state of the crosslinked polymer gel with the temperature, the contrast changes greatly with the temperature as a boundary. Therefore, it is possible to change to a color having a different color tone with a change in temperature with a single particle.

As the fine particles, as described in claim 2, a polymer gel can be used.
Further, as described in claim 3, two or more types of fluorescent dyes serving as the donor or acceptor to be carried on the particles, and at least two sets of the fluorescent dyes in different wavelength regions, You may comprise so that the said excitation spectrum may overlap.
In this case, as described in claim 4, the fine particles are formed in a multi-layer structure including a core and one or a plurality of shells, and the core and the shell are the fluorescent dye or the acceptor serving as the donor. It is also possible to carry a fluorescent dye.
In this way, it is possible to change the color tone to many colors.

As described in claim 5, at least one of the constituent monomer components may use (meth) acrylic acid amino-substituted alkyl ester or N-substituted (meth) acrylamide.
As described in claim 6, the stimulus change responder of the present invention is provided in a one-dimensional, two-dimensional or three-dimensional form with the change-responsive material according to any one of claims 1 to 5 on a substrate. It can be arranged and configured.

  According to the present invention, a change-responsive material capable of changing color tone with a single particle, and capable of vivid coloring with high contrast to the background by using fluorescence, and change using the same A responder can be obtained.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram illustrating a configuration according to an embodiment of the stimulus change responsive material of the present invention.
In the change-responsive material, a donor 3 and an acceptor 4 that cause fluorescence resonance energy transfer under a certain condition are supported on a fine particle 2 that causes a reversible volume change by stimulation such as temperature, and the fine particle is contained in a dispersion medium. It is formed by dispersing.
As the fine particles 2, various known ones can be used as long as they cause the above reversible volume change, and a polymer gel can be used.

  In order to cause fluorescence resonance energy transfer, the fluorescence spectrum of the donor 3 and the excitation spectrum of the acceptor 4 are overlapped, and the donor 3 and the acceptor 4 are close to each other at a certain distance. In the present invention, the donor 3 and the acceptor 4 that overlap in the fluorescence spectrum and the excitation spectrum are supported on the fine particles 2 that cause the volume change and dispersed in the dispersion medium, and the donor 3 and the acceptor according to the volume change of the fine particles 2. 4 is brought close to each other to cause fluorescence resonance energy transfer.

For example, at room temperature, the distance between the fine particles carrying the donor 3 and the acceptor 4 is maintained at a certain distance (distance that does not cause fluorescence resonance energy transfer), and when the excitation light is irradiated, only the fluorescence of the donor 3 is observed. can do. From this state, when the temperature is raised and the volume of the fine particles 2 is changed (reduced in the illustrated example), the donor 3 and the acceptor 4 approach each other, and the distance between the two approaches the distance that causes fluorescence resonance energy transfer. Thereby, the fluorescence energy is transferred from the donor 3 to the acceptor 4, and only the fluorescence of the acceptor 4 can be observed.
Therefore, according to the present invention, by selecting the fluorescent dye of the donor 3 and the fluorescent dye of the acceptor 4 in different colors, a stimulus change response that can change the color tone with a high contrast ratio due to a temperature change. Can be obtained. Moreover, by arranging this stimulus change responsive material on a substrate such as a glass plate or an acrylic plate in a one-dimensional shape (linear shape), a two-dimensional shape (planar shape), or a three-dimensional shape (three-dimensional shape), A stimulus change responder capable of changing the color tone with a high contrast ratio due to a temperature change can be configured.

[Crosslinked polymer gel]
As the fine particles 2 that cause a reversible volume change by a change in stimulus such as temperature, it is preferable to use a crosslinked polymer gel. The crosslinked polymer gel contains alkyl-substituted (meth) acrylamide such as N-isopropyl (meth) acrylamide as a constituent component. The LCST (temperature at which fluorescence energy transfer occurs) of the crosslinked polymer gel can be changed by changing the structure, combination, and composition of the alkyl-substituted (meth) acrylamide.

  Furthermore, as at least one of the components of the crosslinked polymer gel, (meth) acrylic acid, metal salt of (meth) acrylic acid, amino-substituted (meth) acrylamide such as dimethylaminopropyl (meth) acrylamide, dimethylaminoethyl ( It includes monomers having groups that exhibit ionic properties when dissociated, such as (meth) acrylate, amino-substituted alkyl esters such as (meth) acrylate and diethylaminoethyl (meth) acrylate.

  When the crosslinked polymer gel obtained by copolymerizing these monomers and the alkyl-substituted (meth) acrylamide is immersed in water, an ionic group derived from the monomer located on the surface of the crosslinked polymer gel particles is generated. The electrostatic repulsion between these ionic groups increases the dispersion stability of the microparticles and can also serve to bind to donors and acceptors. That is, it is possible to control the amount of donor and acceptor chemically bonded on the gel surface by the mixing ratio of monomers having reactive groups that exhibit ionic properties when dissociated contained in the crosslinked polymer gel. The mixing ratio of the monomer is 0.1 to 10 mol%, preferably 0.5 to 5 mol%, based on the total crosslinked polymer gel. When the amount is 0.1 mol% or less, the dispersion stability is lowered, and the aggregation of fine particles occurs particularly at a high temperature. When the amount is 10 mol% or more, the volume change of the fine particles accompanying the temperature change becomes small.

These crosslinked polymer gels having LCST can be produced by a general polymerization method such as radical polymerization. For example, it is easy by mixing a radical polymerization initiator in an aqueous monomer solution in which the raw material alkyl-substituted (meth) acrylamide such as N-isopropyl (meth) acrylamide, (meth) acrylic acid and a crosslinking agent are dissolved in water. A crosslinked polymer gel can be polymerized, but this is not a limitation. There is also a method in which the monomer aqueous solution is encapsulated in advance in a polymer gel such as an alginate capsule and the monomer is polymerized in the alginate capsule. In the case of this method, the polymerized crosslinked polymer gel can be formed into particles, and the particle diameter can be controlled by the particle diameter of the alginic acid capsule. An example of the cross-linking agent is a polyfunctional monomer such as N, N′-methylenebisacrylamide, but of course not limited thereto.
As the liquid (dispersion medium) used in the material of the present invention, water, an aqueous electrolyte solution, alcohol, a water-soluble solvent, or a mixture thereof can be used.

[Fine particles]
Fine particles (dispersoid) supporting donor and acceptor are prepared by dissolving N-isopropylacrylamide (NIPAM), acrylic acid, N, N′-methylenebisacrylamide, sodium dodecyl sulfate, fluorescein monomer, rhodamine monomer in pure water, To the one degassed with nitrogen gas, potassium persulfate heated to a predetermined temperature and dissolved in a small amount of pure water was added to initiate polymerization, reacted for several hours with stirring, and the reaction solution was put into a dialysis membrane. It can be purified by dialysis against pure water.
As one specific example, 1.67 g of N-isopropylacrylamide, 0.12 g of acrylic acid, 47 mg of N, N′-methylenebisacrylamide, 150 mg of sodium dodecyl sulfate, 10 mg of fluorescein monomer, and 10 mg of rhodamine monomer are dissolved in 50 ml of pure water. Then, 100 mg of potassium persulfate heated to 70 ° C. and dissolved in a small amount of pure water is added to the one degassed with nitrogen gas, polymerization is started, and the mixture is reacted for 7 hours while stirring at 500 rpm. The reaction solution is put into a dialysis membrane and dialyzed against pure water.

[Donor and acceptor]
Examples of donor and acceptor (donor / acceptor) pairs include fluorescein / rhodamine B, fluorescein / tetramethylrhodamine, 6-FAM (6-carboxyfluorescein) / 6-TAMRA (6-carboxytetramethylrhodamine), 1,5- IAEDANS (5-(((((2-iodoacetyl) amino) ethyl) amino) naphthalene-1-sulfonic acid) / fluorescein, EDANS (5-((2-aminoethyl) amino) naphthalene-1-sulfonic acid sodium salt) / DABCYL chloride (4-dimethylaminoazobenzene-4′-sulfonyl chloride) or BODIPY
FL (Molecular Probes) / BODIPY FL (Molecular
A combination of Fluorescein / QSY-7 (trade name of Molecular Probes), Tetramethylrhodamine / Cy5 (trade name of Amersham Pharmacia) can be used.

As described above, it is possible to change the color tone in various ways by changing the combination of the donor and the acceptor (donor / acceptor). Therefore, by appropriately combining a plurality of crosslinked polymer gels having different LCSTs (temperatures at which fluorescence energy transfer occurs) and a plurality of pairs of donors and acceptors, a stimulus change responsive material having three or more colors in the course of temperature changes It is possible to change the color.
These donors and acceptors are supported on fine particles by (1) copolymerization when a polymer group such as a vinyl group is previously introduced into a fluorescent dye to synthesize a crosslinked polymer gel, and (2) crosslinking A method of forming a covalent bond by reacting a functional group of an amino group or a carboxy group introduced into a polymer gel with a functional group of a fluorescent dye after polymerization, (3) ionic groups of a crosslinked polymer gel and ions of the fluorescent dye There is a method of fixing by an electrostatic interaction between sex groups.

The efficiency (E) of fluorescence resonance energy transfer is given by the known formula E = 1 / [1+ (R / R ₀ ) ⁶ ]
However, it is preferable that the distance between the donor and the acceptor varies within a range of 20 to 100 cm, preferably within a range of 30 to 70 cm, due to a volume change of the polymer gel.

[Other Embodiments]
In another embodiment of the present invention, a plurality of combinations of donors 3 and acceptors 4 that cause fluorescence resonance energy transfer at different temperatures are prepared, and each set is supported on a common particle 2 or different particles 2 in a dispersion medium. To disperse.
In the example shown in FIG. 2, the fine particle 2 has a double structure of an inner core 21 and an outer shell 22 as shown in (a), and a donor 31 and an inner or surface of the core 21 as shown in (b). A pair with the acceptor 41 is carried, and a pair of the donor 32 and the acceptor 42 is carried inside or on the surface of the shell 22 as shown in FIG.

For the pair of donor 31 and acceptor 41 and the pair of donor 32 and acceptor 42, polymer gels having different LCST (lower critical solution temperature) are selected for the core 21 and the shell 22 so that the fluorescence energy shifts at different temperatures. To do. At this time, it is preferable to select one having a temperature difference as large as possible so that a large contrast difference can be obtained.
By doing so, it is possible to change the color tone of the stimulus change responsive material to three or more colors in the process of change from the temperature T1 to the temperature T2 and the process of change from the temperature T2 to the temperature T3.

  Examples of the fine particles having a double structure of the inner core 21 and the outer shell 22 as shown in FIG. 2A include a core-shell polymer. Such a core-shell polymer can be formed by a known method in JP-A-07-070255, JP-T-2001-518527, JP-A-05-017514 and the like. For example, Japanese Patent Application Laid-Open No. 07-070255 discloses a core-shell polymer by a continuous multi-stage emulsion polymerization method so-called seed emulsion polymerization method in which a polymer in a subsequent stage is sequentially coated in the presence of a polymer in a previous stage. A method of forming is disclosed.

コア（ko-96）を以下の方法で形成した。
次に、このコア３０ｍｌに含まれる温度応答性ポリマーの量を計算し、以下のように乳化重合を行った。

[Experimental example]
The experimental results using the core-shell type fine particles of the other embodiment are shown below.
(1) Manufacture of core and shell

A core (ko-96) was formed by the following method.
Next, the amount of the temperature-responsive polymer contained in 30 ml of the core was calculated, and emulsion polymerization was performed as follows.

Here, iPA: N-isopropylacrylamide, dEA: N, N-diethylacrylamide, SDS: surfactant (sodium dodecyl sulfate), BIS: N, N′-methylenebisacrylamide, KPS: initiator (sodium persulfate) SPMA: 2-acrylamido-2-methyl-1-propanesulfonic acid, Pro: proflavine monomer, Rhod: rhodamine monomer, Flu: fluorescein monomer.
As a result, about 2/3 of the monomer added by ko-102 was polymerized as a shell.

(2) Temperature shrinkage of the core and shell obtained as a result of the above Core (ko-96) 12.8 ° C. d = 106.4 nm 24.3 ° C. d = 66.4 nm
Shell (ko-102) d = 118.3 nm at 12.9 ° C. d = 80.2 nm at 25.4 ° C.
(3) Results of Fluorescence Intensity Change FIG. 3 shows a graph of the fluorescence intensity change using the above core-shell fine particles.
As can be seen from the graph of FIG. 3, in this experimental example, the light emission of the three dyes is equal at 20 ° C. or lower, but the blue and green light emission decreases and the red intensity increases at 21 ° C. to 25 ° C. Luminescence increases for all three colors from ℃ to 33 ℃.

Although a preferred embodiment of the present invention has been described, the present invention is not limited to the above-described embodiment.
For example, in the above description, the temperature is taken as an example of the stimulus, but the stimulus change responsive material that causes a volume change by other stimuli such as light, current, and ph can be widely applied.
In the above-described other embodiments, the core-shell type fine particle having a double structure in which a single shell is formed around the core has been described as an example. However, the multi-layer core-shell type fine particle having two or more shells has been described. By using, the color to be changed can be diversified. Furthermore, for the diversification of the color tone, it is not always necessary to use the core-shell shape, and a plurality of sets of donors and acceptors may be supported on the surface of a single fine particle.

  The stimulus change responsive material of the present invention can be applied to, for example, a display device such as a display, or a light control glass that automatically changes contrast according to temperature or light intensity. In addition, the temperature can be measured by observing the color tone of a single fine particle under a fluorescence microscope, and the temperature management of a specimen such as a cell becomes easy.

It is the schematic which concerns on one Embodiment of the stimulus change responsive material of this invention, and demonstrates the structure. It is an example which made the microparticle which carry | supports a donor and an acceptor concerning other embodiment of this invention into the core-shell type. It is an example of experiment concerning other embodiments of the present invention, and is a fluorescence intensity change graph using core shell type fine particles.

Explanation of symbols

2 Fine particle 21 Core 22 Shell 3 Donor 31, 32 Donor 4 Acceptor 41, 42 Acceptor

Claims (6)

In a stimulus change responsive material whose fluorescent color changes due to a change in stimulus,
In the dispersion medium, fine particles that reversibly change volume due to a change in stimulation are dispersed.
The fine particles carry a fluorescent dye that becomes a donor and an acceptor fluorescent dye in fluorescence resonance energy transfer, and the fluorescent dye that overlaps the excitation spectrum of the donor's fluorescence spectrum and the acceptor,
A stimulus change responsive material characterized by. The stimulus change responsive material according to claim 1, wherein the fine particle is a polymer gel. Two or more types of fluorescent dyes serving as the donor or acceptor supported on the fine particles are used, and at least two sets of the fluorescent dyes have an overlap of the fluorescence spectrum and the excitation spectrum in different wavelength regions. The stimulus change responsive material according to claim 1 or 2. The fine particles are formed in a multi-layer structure including a core and one or a plurality of shells, and the core and the shell carry a fluorescent dye serving as the donor or a fluorescent dye serving as the acceptor. The stimulus change responsive material according to claim 3. The stimulus change responsive material according to any one of claims 1 to 4, wherein at least one of the constituting monomer components is (meth) acrylic acid amino-substituted alkyl ester or N-substituted (meth) acrylamide. 6. A stimulus change responder characterized in that the change responsive material according to claim 1 is arranged one-dimensionally, two-dimensionally or three-dimensionally on a substrate.

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