JPS62221467A - Method for preparing purple membrane-containing membrane - Google Patents

Abstract

PURPOSE:To efficiently form a highly homogenous membrane layer, by treating the surface of a substrate with a coupling agent and forming a purple membrane-containing membrane layer due to the polymerization of acrylamide to the treated surface. CONSTITUTION:A purple membrane is the one isolated from Halobacterium halobium being one kind of halophil and contains bacteriorhodopsin being chromoprotein and is dissolved in an aqueous solution containing 5-15wt% of acrylamide to obtain a desired acrylamide solution. A substrate such as a glass substrate, an ITO electrode substrate or a metal plate is treated with a silane coupling agent and acrylamide is polymerized while the acrylamide solution containing the purple membrane is contacted with the surface of the surface treated substrate to form a homogenous membrane layer of a purple membrane-containing acrylamide gel.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a new method for producing purple film-containing thin films. In more detail.

The present invention relates to a method for efficiently forming a purple membrane-containing thin film layer with excellent homogeneity on a substrate such as glass or metal, which is useful as a biodevice having a photoresponsive function.

Conventional technology Recently, the limits of microfabrication technology for electronic devices using silicon 1, such as ultra-LSI, have begun to appear, and the physical limits of the devices themselves are expected, so we are trying to assemble devices at the single molecule level. Along with this, the concept of molecular electronic devices was proposed.

Research into new devices that imitate biological materials such as proteins, lipids, and nerve cells, so-called bio-devices, has begun to be actively conducted. Since this biodevice can perform signal transmission and processing at the molecular level, it is said that it is possible to create a device with a size of 10 μm or less.

By the way, one type of highly halophilic bacterium...Halobacterium halo
Since the purple membrane discovered from the bioluminescence membrane contains the pigment protein bacteriorhodopsin and has a special light-responsive function, it is expected to be used as a biodevice, such as a switching element or a memory element. Currently, research on its use is actively being conducted.

In order to make this purple film into a device, it is necessary to laminate it in the form of a thin film on a substrate such as glass. To date, there have been only 1 methods for forming a thin film layer containing the purple film on a substrate, for example. (1) Casting method using a purple membrane-containing suspension (
2) Electrodeposition method, (3) method using centrifugal force, etc. are known. Among these methods, the casting method is relatively easy to perform, and the electrodeposition method and the method using centrifugal force are advantageous in that they can produce an oriented thin film of purple film, but neither method is sensitive to light. When used as a biodevice having a response function, the resulting thin film layer has insufficient homogeneity.

Problems to be Solved by the Invention The purpose of the present invention is to solve the problems of the conventional methods and to develop a thin film containing a violet membrane that has excellent homogeneity and is useful as a biodevice having a photoresponsive function. An object of the present invention is to provide a method for efficiently forming a layer on a substrate such as glass.

Means to Solve All Problems As a result of extensive research, the present inventors treated the surface of the substrate with a coupling agent, and created a thin film layer containing a purple film on this surface by utilizing the polymerization reaction of acrylamide. The inventors have found that the object can be achieved by forming such a structure, and have completed the present invention based on this knowledge.

That is, in the present invention, a purple film is formed on the surface of the substrate by contacting a substrate whose surface has been previously treated with a coupling agent with an acrylamide solution containing a purple film isolated from a halophilic bacterium, and then bringing the substrate to polymerization conditions for acrylamide. The present invention provides a method for producing a thin film containing purple membrane, which comprises forming a polyacrylamide-containing gel layer.

The purple membrane used in the method of the present invention is produced by Halobacterium halobium, a type of highly halophilic bacterium.
halobium) and contains one chromoprotein, bacteriorhodopsin. This bacteriorhodopsin is the pigment vitamin A
Vitamin A alone has an absorption band around 380 nm, which undergoes an open shift due to binding with protein and is shifted to around 570 nm.

Therefore, by changing the interaction mode between protein and vitamin A, a color change can be caused. To change this interaction mode, for example, thermal denaturation of proteins can be effectively used.

In the method of the present invention, a glass substrate or an ITO substrate is used as the substrate.
An electrode plate, a transparent substrate such as a 5n02 electrode plate, a metal plate, a plastic plate, etc. are used.

In addition, coupling agents used for surface treatment of these substrates include silane-based, titanate-based, and aluminum-based coupling agents, among which silane-based coupling agents are particularly suitable for glass substrates. It is. Examples of such silane coupling agents include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltris(2-methoxyethoxy)silane, vinyltriacetoxysilane, and γ-methacryloxypropyltrimethoxysilane.

The treatment of the substrate surface with a coupling agent is carried out by, for example, dissolving the desired coupling agent in a solvent, immersing the substrate in this solution, evaporating the solvent adhering to the substrate, and then heating and drying. be exposed.

In the method of the present invention, the acrylamide solution containing a purple film is brought into contact with the substrate surface treated with a coupling agent in this way, and the acrylamide is polymerized, thereby forming a polyacrylamide containing a purple film on the substrate surface. A thin layer of gel is formed. The acrylamide solution containing the purple membrane used in this case can be prepared by dissolving the purple membrane in an aqueous solution containing acrylic abadola in a range of 5 to 15 weight percent.

The concentration of the purple membrane is not particularly limited and can be selected from a wide range. In this case, a buffer such as an acetate buffer can be used as the medium, if necessary.

There are no particular restrictions on the method of bringing the acrylamide monomer solution containing the purple film into contact with the substrate surface, but for example, a cell is created with the substrate and a resin plate such as an acrylic resin, and the acrylamide bath liquid is injected into this cell. A method such as this can be used.

Polymerization of acrylamide is initiated by a radical generator such as ammonium persulfate or a photoradical generator such as poflavin, as in conventional methods, and is usually carried out at room temperature.

The purple film-containing polyacrylamide gel produced in this way is firmly bonded to the substrate surface by the coupling agent, so the substrate is washed with water to remove low molecular substances such as unpolymerized monomers, and then dried. By doing so,
A thin layer of purple film-containing polyacrylamide gel can be formed on the substrate.

The thin layer of purple-containing polyacrylamide gel formed on the substrate by this method exhibits a transparent purple color and has good homogeneity. When irradiated with light, the pigment protein bacteriorhodopsin in the purple membrane undergoes thermal denaturation, and only the irradiated area changes from purple to yellow.

In this way, the laser irradiation spot recorded on the purple film-containing thin film layer is stable for a long time under normal circumstances.

Example Next, the present invention will be explained in more detail with reference to Examples.

For example, from halophilic bacteria to purple membrane, ``Preparative Biochemistry''.
) J Vol. 5, pp. 161-171 (1975)
It was isolated according to the method described in .

A glass substrate of 50 x 50 x 1 m was immersed in an ethanol solution containing 2.0% of γ-methacryloxypropyltrimethoxysilane, a silane coupling agent, and air-dried.
It was dried by heating for a minute.

Next, the glass substrate whose surface was treated with a coupling agent in this way is attached to an acrylic resin plate via a spacer with a thickness of 10.511 ft to constitute a cell for gel production. Acrylamide monomer liquid containing (acrylamide monomer 7.5% by weight, ＼0
．． 05 molar acetate buffer pH 5.5) 1.2 m/' (H) was injected and polymerization was carried out at room temperature in a conventional manner.

After confirming that one polymerization was completed approximately 30 minutes after the start of polymerization, the cell was disassembled and the glass substrate was taken out, and then washed by immersion in distilled water to remove low-molecular substances such as unpolymerized monomers. Thereafter, by drying and dehydrating in a dryer, a thin layer of purple membrane-containing polyacrylamide gel could be formed on the glass substrate.

The purple film-containing thin film layer formed in this way exhibits a transparent purple color and has good homogeneity.

When laser light was irradiated using a 100 mW argon ion laser using an appropriate lens system, only the irradiated area changed from purple to yellow. The laser beam irradiation time was 2 milliseconds, and the size of the irradiated area was approximately 20 μm in diameter according to microscopic observation.

In this way, the laser irradiation spot recorded on the purple film-containing thin film layer was stable for a long time under normal circumstances.

Effects of the Invention According to the method of the present invention, it is possible to form a purple film-containing thin film with excellent homogeneity on a substrate such as glass very easily. It is possible to cause a color change, and as a biodevice containing a photoresponsive function, it can be expected to be applied to μμ Kan-Sori LL Otsuriko, etc.

Claims (1)

[Claims] 1. A substrate whose surface has been previously treated with a coupling agent is brought into contact with an acrylamide solution containing a purple membrane isolated from a halophilic bacterium, and then brought to polymerization conditions for acrylamide to form a purple membrane-containing polyacrylamide gel layer on the surface of the substrate. A method for producing a thin film containing a purple film, the method comprising: forming a thin film containing a purple film.