JPH03163886A - Bioelement - Google Patents

Abstract

PURPOSE:To utilize a bioelement for constructing a bio-computer having an information processing type simulating the visual sense of an organism by arraying liposomes composed of a living organism substance converting incident light into membrane potential fluctuation and a living-organism simulated substance onto a substrate in a two-dimensional manner. CONSTITUTION:Liposomes (artificial follicles) 30 formed by using one or both of a living organism substance capable of converting incident light into potential fluctuation on the inside and the outside of a membrane and/or a living-organism simulated substance are arrayed onto a substrate 41 in a two-dimensional manner, thus arranging the liposomes 30 in a very fine shape. Consequently, the field of the same minute membrane potential fluctuation as the field of membrane potential fluctuation in visual cells on a retina is acquired. Accordingly, a bioelement can be utilized for constructing a bio-computer having an information processing type simulating the visual sense of an organism.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is directed to the development of a biological device that imitates the optical information processing function of living organisms.

(Prior Art) Conventional computers are made using silicon semiconductor elements, etc.
It was a von Neumann computer (hereinafter referred to as a Neumann computer) that executed serial logical operations using the von Neumann method. Although this method was able to perform quick logical operations, it had the drawback that it was essentially difficult to process a large number of information in parallel.

Based on this (and knowledge of biology, cerebral physiology, etc.), many researchers have made attempts to realize computers such as so-called biocomputers, which have various functions that could not be satisfied with the Neumann type computer. has been done.

One example is a biocomputer that attempts to process visual information by imitating the visual function, which is a relatively well-researched biological function.

Here, the visual function in a living body is as explained below.

As is well known, the eye, which is the organ responsible for vision, is made up of photoreceptor cells. These photoreceptor cells, especially the cells arranged on the retina, can be roughly divided into cone cells, which distinguish colors, and rod cells, which detect brightness and darkness.

FIG. 5 is a schematic diagram of a rod cell (hereinafter sometimes referred to as a rod). 11 is a disc membrane, 13 is a connecting cilia, 15 is a mitochondria, 17 is a Golgi apparatus, 19 is a myoid, 21 is a nucleus, 23 is an outer segment, 25 is an inner segment, 27 is a synaptic junction, and 28 is a rod.

When light enters the rods 28 arranged in the retina from the outside (left side of the drawing), changes occur in rhodobusin, a photoresponsive protein present in the disc membrane 11, and this rhodobusin (which is covalently bonded as a prosthetic group) By changing into cis-retinal or trans-retinal, calcium ions contained within the disc membrane 11 are released into the cytoplasm.

The increased calcium ions in the cell membrane close the sodium channels in the cell membrane of the outer segment 23, causing hyperpolarization of the cell's membrane potential. This becomes a signal to the synaptic junction 27, reducing the release rate of inhibitory neurotransmitters and causing excitation of post-synabular neurons. These signals propagate between neurons one after another and are processed at a high level in the brain. In this way, visually,
The field of changes in membrane potential of photoreceptor cells on the retina caused by light is processed by the brain and recognized as a pattern.

(Problem to be solved by the invention) However, when constructing a biocomputer that imitates the visual function described above, the role of photoreceptor cells is replaced by a photoresponsive device such as a photodiode using an inorganic or organic semiconductor. If you try to achieve this with a photoreceptor cell, you can use a two-dimensional array of photodiodes to obtain external information using a current generated by converting photons, which are information from the outside, into electrons. It is difficult to obtain a field of current change corresponding to the field of membrane potential change, since there are limits to the fine arrangement of photodiodes and the like.

This invention has been made in view of these points, and therefore, the purpose of this invention is to provide a bioelement that can be used to construct a biocomputer with an information processing form that imitates the visual sense of living things. be.

(Means for Solving the Problems) In order to achieve this object, the biodevice of the present invention is formed using one or both of a biological material and a biosimilar material, and the incident light is converted to a membrane potential. It is characterized by a two-dimensional array of liposomes that convert into a substance on a substrate.

In carrying out this invention, it is preferable to encapsulate a membrane potential-sensitive fluorescent dye within the aforementioned liposome.

Furthermore, in carrying out the present invention, it is preferable to immobilize the liposomes to the substrate using an antigen-antibody reaction.

(Function) According to the biodevice of the present invention, liposomes (artificial vesicles) made of a biological material and/or biosimilar material that can convert incident light into potential changes inside and outside the membrane are arranged two-dimensionally on a substrate. Furthermore, since liposomes can be arranged very finely, a field of precise membrane potential changes similar to the field of membrane potential changes in photoreceptor cells on the retina can be obtained.

In addition, when a membrane voltage-sensitive fluorescent dye is encapsulated in a liposome, a field of membrane potential change and a field of fluorescence intensity change corresponding to this field are obtained, which greatly increases the utilization of the biodevice. .

In addition, when immobilizing liposomes on a substrate by an antigen-antibody reaction, the procedure is to first form a certain film on the substrate from antibodies, and then irradiate unnecessary parts of this film with an ion beam such as gallium ions. After denaturation and removal, a two-dimensional pattern is created using the remaining antibody, and then liposomes can be immobilized on this antibody. Therefore, since the liposome itself is not processed by an ion beam or the like, a biodevice can be obtained without causing any deterioration of the liposome.

(Example) Hereinafter, examples of the biodevice of the present invention will be described in detail with reference to the drawings. Note that each figure used in the explanation schematically shows the dimensions, shapes, and arrangement relationships of each component to the extent that the present invention can be understood.

Liposomes are prepared using biological materials and biological materials, and liposomes that convert incident light into changes in membrane potential are prepared as described below.

First, 94% by weight of the phospholipid dipalmitoylphosphatidylcholine (manufactured by Sigma) represented by the following formula, and the following ■
A mixed lipid containing 1% by weight of a phospholipid antigen represented by the formula and 5% by weight of a diazocarboxylic acid lipid represented by the following formula (2) is prepared. Note that the phospholipid antigen represented by the formula (2) was obtained by synthesis.

On the other hand, for example, 3,3'-
KCI! 93mM and NaCI! An aqueous solution containing 7mM is prepared. Here, the content of diS-03(5) is set to a value that provides the required fluorescence intensity. When not obtaining fluorescence intensity, diS-C3 (5) is not used.

Next, the above mixed lipid is dispersed in this aqueous solution. Furthermore, after applying ultrasonic waves to the obtained lipid suspension, this suspension is centrifuged under the conditions of 100.0009. Liposomes contained in the supernatant after centrifugation are used to construct the biodevice of this invention.

A schematic diagram of the structure of the liposome prepared as described above is shown in the second figure.
As shown in the figure. As can be understood from FIG. 2, this liposome 30 contains diS-03 (5) 37 as a membrane potential-sensitive fluorescent dye inside, and is roughly composed of the phospholipid dibalmitoylphosphatidylcholine 31. The separated lipid bilayer contains 358 diazocarboxylic acid lipids. Furthermore, as can be understood from the formula (2), the phospholipid antigen 33 has an aromatic ring in its parent group, so the head polar group is bulky. Therefore, phospholipid antigen 33
is the phospholipid dibalmitoylphosphatidylcholine 31
It has a high probability of being present on the side of the lipid bilayer with greater curvature, that is, on the outside of the lipid bilayer, as shown in FIG. 2, and is present on the outer wall of the lipid bilayer as shown in FIG.

Next, in order to investigate the properties of the liposomes prepared as described above, a small amount of the ribbon-like suspension (the above-mentioned soil solution) was mixed with K (
1 to an aqueous solution containing 7mM of NaCA and 93mM of NaCA and stirred. Next, the stirred solution is intermittently and alternately irradiated with light with a wavelength of 360 nm that causes a trans-cis change in the diazo group of the diazocarboxylic acid lipid and light with a wavelength of 450 nm that causes a cis-trans change. Roughly, the wavelength is 622 nm during the irradiation stop period of both lights.
The solution is excited by irradiation with light, and the fluorescence intensity (') at a wavelength of 670 nm is measured.In addition to the measurement of the fluorescence intensity described above, the change in membrane potential of the liposome (positive depolarization) ΔE
is directly measured using a microelectrode.

The measurement results of fluorescence intensity ( ) and membrane potential are plotted on the vertical axis as the rate of change in fluorescence intensity ΔF (%) and the change in membrane potential ΔE (mV
) and time is plotted on the horizontal axis as shown in Figure 3. Here, Δ
F is determined by the following formula (■).

However, "." in formula (2) is the fluorescence intensity obtained from the solution when the solution is sufficiently irradiated with 450 nm light until the diazocarboxylic acid lipid completely changes to the trans type.

ΔF=100 (F Fo ) /Fo ・=■
Also, among the points marked with arrows along the time axis in Figure 3, the points marked with Δ mean the points where the solution was irradiated with 360 nm light, and the points marked with marks indicate the points where the solution was irradiated with 360 nm light. Against 450n
m means the point irradiated with light. Of course, each point is irradiated with light for a certain predetermined period of time.

As is clear from Figure 3, the degree of change in Δ' and ΔE is almost the same in both cases, and the liposome prepared as described above changes the membrane potential of the incident light. Furthermore, it is found that the change in membrane potential can be converted into a change in the fluorescence intensity of the fluorescent dye contained in the lipome.

The reason why the membrane potential of this liposome is depolarized by 360 nm light is because the diazocarboxylic acid lipid in the liposome changes from the trans type to the cis type, which changes the structure of the liposome membrane and increases ion permeability. This is thought to be for the purpose of

Next, in order to prepare the biodevice of this invention, we will explain the processing operation (techniques) for forming the antibody as a monomolecular film on the substrate.In this example, we will discuss the flatness of the substrate surface and the processing operation. A case will be described in which a glass substrate is used as the substrate due to its simplicity.However, the substrate may be made of any other suitable material such as polystyrene.

First, the substrate surface is hydrophobized by pre-immersing the substrate in octadecyltrichlorosilane.

In addition, the antibody γ-globulin obtained against phospholipid antigen 35 (see Figure 2, especially near the aromatic ring of the
(uir-Blodc+ett) Film Formation Device A monomolecular film of the antibody is formed on the aqueous solution by compressing the surface of the aqueous solution. Because of their distribution, they are formed in a certain direction, ie, with the antigen-binding region of the antibody facing down.

Next, the monomolecular film made of this antibody is transferred to the surface of the substrate whose surface has been made hydrophobic by a horizontal adhesion method to form a C-L8 film on the substrate. Figure 4 shows the substrate 4 in this state.
FIG. 11 is a schematic cross-sectional view of a substrate 11Fr. 43 indicates an LB membrane made of antibodies. The antibody is transferred once so that the antigen-binding region faces the side opposite to the substrate 41 side (in the upward direction of the substrate).

In this example, the substrate 4 is formed using a 1B film forming apparatus M.
However, for simplicity, the antibody can be adsorbed onto the substrate 41 by dissolving the antibody in an appropriate solution and directly immersing the hydrophobically treated substrate 41 in this solution. can be done.

Liposome 2; 1. Next, the substrate 41 on which the LB film of the antibody has been formed is immersed in the liposome suspension (the above-mentioned supernatant) to perform an antigen-antibody reaction, and the liposome is A two-dimensional array is formed on the substrate 41. As a result, the biodevice of Example is obtained.

FIGS. 1(A) and CB) are diagrams that provide an explanation of this biodevice. In particular, FIG. 1(A) shows the liposome 30
FIG. 1 (8) is a diagram schematically showing a state in which the substrate 41 is fixed. FIG. 1 (8) is a diagram schematically showing a part of the biodevice of the example.

Note that when arranging liposomes in a predetermined two-dimensional pattern, first the unnecessary portions of the LB film 43 made of antibodies on the substrate 41 are denatured by irradiating them with an ion beam such as gallium ions or a scanning electron beam. It is preferable to create a predetermined two-dimensional pattern from the remaining antibody after removing it, and then fix ribosomes to this antibody. According to this method, the liposome itself is processed by an ion beam electron beam. This is preferable because deterioration of the liposomes can be prevented.

Next, the biodevice of the example prepared as described above was transferred to K(
As in the case of the liposome suspension,
After irradiating the bio-device with light with a wavelength of 360 nm or 450 nm, the bio-device was irradiated with light with a wavelength of 622 nm to excite the bio-device, and the fluorescence intensity at a wavelength of 670 nm was measured. As a result, it was found that even in the state of the biodevice, the fluorescence intensity changes corresponding to the change in the membrane potential of the ribbon beam, as shown in FIG. 3.

Although the embodiments of the biodevice of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various changes and modifications as described below can be made.

First, the numerical conditions described in the above-mentioned embodiments are preferred examples to facilitate understanding of the present invention, and it is clear that changes in the design are possible within the scope of the purpose of the present invention. .

In addition, in the above example, a diazocarboxylic acid lipid was used to prepare the biodevice, but the same effect as in the example may be obtained by using other organic materials such as subirobilan or biomaterials such as rhodobucin instead. You can expect great effects.

(Effects of the Invention) As is clear from the above explanation, the biodevice of the present invention can convert incident light into a field of membrane potential changes in two-dimensionally arranged lipomes. Moreover, by incorporating a membrane potential-sensitive fluorescent dye into liposomes, incident light can be converted into a field of fluorescence intensity changes in a two-dimensional array of soponomes. Therefore, it can be used as an information processing device, an input device, an output device M, etc. of a biocomputer that has an information processing form that imitates the visual sense of living things.

[Brief explanation of the drawing]

Figures 1 (A) and (B) are diagrams for explaining the biodevice of the example, Figure 2 is a diagram schematically showing the structure of the liposome of the example, and Figure 3 is a diagram for explaining the biodevice of the example. A diagram showing the photoresponse characteristics of liposomes and biodevices, FIG. 4 is a diagram for explaining the antibody-attached substrate, and FIG.
FIG. 2 is a diagram schematically showing rod cells. 30... Liposome 31... Phospholipid conjugate dipalmitoyl phosphatidyl] Phosphorus 33... Phospholipid tributary antigen 35... Diazocarboxylic acid lipid conjugate 37... Membrane potential sensitive fluorescent dye 41... Substrate, 43 ···antibody.

Claims (1)

[Claims] (1) It is characterized by a two-dimensional array of liposomes formed using one or both of a biological material and a biosimilar material and converting incident light into a change in membrane potential on a substrate. Bio-element. (2) The biodevice according to claim 1, wherein the liposome includes a membrane potential-sensitive fluorescent dye. (3) The biodevice according to claim 1 or 2, wherein the liposome is immobilized on the substrate using an antigen-antibody reaction.