JPH0453280A - Bioelement excitation artificial film - Google Patents

Abstract

PURPOSE:To decrease or eliminate an outer pressure which is required for starting an oscillation of short period by a method wherein mixed lipoid composed of dioleyl phosphate represented by a specific structural formula and glycolipid represented by a specific structural formula is mixed at a certain ratio, and the mixture concerned is adsorbed in a porous film. CONSTITUTION:Synthetic lipoid dioleyl phosphate represented by a formula I and glycolipid represented by a formula 4 are mixed to prepare mixed lipoid. The mixing ratio of glycolipid to mixed lipoid ranges from 1 to 40% by weight. The mixed lipoid is dissolved into benzene, a porous film formed of cellulose ester is dipped into the solution concerned, the porous film is picked up from the solution, benzene is evaporated to enable the porous film to adsorb the mixed lipoid, and the mixed lipoid adsorbed porous film is made to serve as an excitation artificial film.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention imitates the information expression and transmission functions in biological nerve cells, etc., and can be used for bio-elements that can be used as sensors for various recognition purposes. , concerning excitable artificial membranes.

(Prior art) A conventional cosibuter is composed of silicon semiconductor elements, etc.
One that executes serial logical operations using the N e IJ r n a n n ) method (hereinafter referred to as the Neumann type).
It is called a nintenitor. ) Teaputo.

However, the main problem with von Neumann type computers is whether they are suitable for performing accurate logical operations, or whether they are suitable for performing the large amount of information processing required for pattern recognition in parallel.

This (Jino Kokari, higher organisms easily perform pattern recognition, learning, and memory.

Zoko C5 Noimashi type that imitates the function of a living creature like a spider]
To build a biocomputer, which is a biocomputer, we have implemented functions that could not be satisfied with the computer. Efforts are being made to imitate living organisms from various angles.

For example, research results or literature on excitable artificial membranes using the lipids that make up the plasma membrane of living organisms
), 12 (1), pf), 12-21, (198
7)).

This document describes that the p-artificial membrane is composed of a porous membrane adsorbed with dioleyl phosphate, and one side of the p-artificial membrane is brought into contact with an electrolyte with a high salt concentration, and the other side is brought into contact with an electrolyte with a low salt concentration. It has been reported that when the temperature rises, a predetermined electrical difference is generated at the gates of these electrolytic solutions over a period of several minutes or several tens of minutes, and electrical impulses are generated. Self-assisted oscillation with such a period is called long-period oscillation. Furthermore, in addition to contacting the artificial membrane with two electrolytes with different salt concentrations, by applying a direct current and a predetermined pressure to the artificial membrane,
There have also been reports of self-excited oscillation with a period of several seconds called short-period oscillation.

According to this document, the above-mentioned self-oscillation is caused by a change in the degree to which the pores of the porous membrane are filled due to a phase transition in which dioleyl phosphate changes from an oil droplet state to a multilayer film state. When is it occurring?

Such a self-oscillation phenomenon of an artificial membrane is a phenomenon similar to the excitement of a living body. Therefore, it is thought that it will be possible to use this artificial membrane (hereinafter referred to as excitatory artificial membrane) to construct biological elements that mimic the functions of neurons and synapses. For example, the patent application filed in 1983-19 by this applicant
No. 2116 (Japanese) proposes a biodevice constructed using the above-mentioned excitable artificial membrane.

(Problem to be solved by the invention) However, in the above-mentioned 1 and conventional excitable artificial membranes for biodevices, when it is desired to change the period and generate short-period oscillation, it is necessary to use two electrolytes with different salt concentrations. There was a problem in that in addition to sandwiching the membrane and passing a direct current through the artificial membrane, external pressure had to be applied.

Even if it is unavoidable that two electrolytes are required and a DC current is required,
It would be beneficial if external pressure could be reduced or eliminated, since constraints on bioelement design would be alleviated.

This invention has been developed in view of these points, and therefore, an object of the invention is to reduce the external pressure necessary for short-period oscillation compared to conventional excitable artificial membranes. An object of the present invention is to provide an aperture artificial membrane for a high') f element that can reduce the noise.

(Means for Solving the Problems) In order to achieve this object, the excitable artificial membrane for bi-j elements of the present invention has a geo[
It is characterized in that it is made by adsorbing a mixed lipid consisting of noyl phosphate and a glycolipid represented by the following structural formula (1) into a porous membrane (where n in the formula (2) represents a positive integer value. ).

CH3(CL)7cH-cH(C1h)7CH,3(C
H2) 7CH= CH(C1''䃮C-D-CH7 C-0-C[4-CH2-(CeH+.0,)τ Kano...
・■ In carrying out this invention, the above-mentioned glycolipids are replaced with the following ■
It is preferable that the glycolipid is expressed by the formula, and the amount of mixed lipid (the total amount of the mixed lipids is 1% by weight or more and 4% by weight or less) for 1 g of lipid.

(Function) The excitable artificial membrane for biodevices of the present invention has the advantage that the external pressure that is initially necessary to cause short-period oscillation can be applied to Compared to excitable artificial membranes, the power can be reduced further (or even rendered useless).The reason for this is not clear, or may be a phase transition of the lipids, which is considered to be the cause of self-oscillation, or a phase transition of the lipids. I suspect that this may occur more easily with a mixture of glycolipids than with rail phosphate alone.

(Example) Examples of the excitable artificial membrane for biodevices of the present invention will be described below with reference to the drawings.

In addition, the chemical name, numerical conditions, equipment used, etc. mentioned in the following explanation +1. There are many preferred embodiments within the scope of the invention.

Therefore, it should be understood that the present invention is not limited to these chemicals, numerical conditions, devices used, etc.

First, a synthetic lipid thioleylbosphae-f(dio]eyl phosphate (hereinafter sometimes abbreviated as DOPH) represented by the following formula 0) is prepared. In this case, D OP +-1 is obtained by reacting oleyl alcohol (manufactured by Kanto Kagaku ■) and phosphorus oxychloride (P○Cρ3) (manufactured by Kanto Kagaku ■) by a well-known synthetic means. It is obtained by hydrolyzing the resulting synthetic substance and further purifying it by chromatography. The porous membrane used is one made of cellulose ester and has a pore diameter of 8 um (in this example, a Millipore filter manufactured by Millipore).

In addition, glycolipids are those represented by the following formula 0 (a glycolipid of the following formula (■), which is a sugar bonded to a lipid) -S C
- use something). This is done using a predetermined method (composition L).

Cfl+(CH2)7cH・CH(Cl"2)7C-
0-CH2□CH7OH Next, a mixed lipid consisting of DOPH and a glycolipid represented by the following formula (4) is prepared. In this example, 1j: First, a mixed lipid containing 20% by weight of the glycolipid in the mixed lipid is prepared.

Next, this mixed lipid is dissolved in Hensen, and then the above-mentioned porous membrane made of cellulose ester is immersed in this solution. After that, this porous membrane is taken out of the solution (the nohensen is evaporated). In this way, the excitable artificial membrane of the example in which the mixed lipid is adsorbed is produced. Adsorption M (well, after drying the excitable artificial membrane, 4 m 9/cm 2 of mixed lipid or porous membrane)
The amount of saliva deposited is controlled to be adsorbed. This control can be mainly controlled by the concentration of the mixed lipid in Hensen's solution, the speed at which the porous membrane is pulled up from the solution, etc.

Next, as shown in FIG. 2, the excitable artificial membrane 1 of the example]
One side was in contact with a 100mM Cρ solution 15a contained in the first electrolytic cell 13a1, and the other side was in contact with a 1.5mM KCf2 aqueous solution 15b contained in the second electrolytic cell 131. Attach it to the self-oscillation confirmation device. FIG. 2 is a diagram schematically showing the configuration of a self-sustained oscillation confirmation device used in this example to confirm self-sustained oscillation of the excitable artificial membrane of the example or comparative example.

Standard electrodes 17a and 23au are in one KCβ aqueous solution 13a of this self-oscillation confirmation device, and KCβ aqueous solution 1 in the other
Standard electrodes 17b and 23b are immersed in the 5b. Then, the standard electrode 17a immersed in the 100mM KCρ solution 15a was placed on the anode side of the DC power supply 19 at a concentration of 5mM.
The standard electrodes 17b in the KCρ aqueous solution 15b are connected to the cathode sides of the DC power supply 9, respectively, and the standard electrodes 23a and 23b are used to measure and record the difference in electric potential of the artificial membrane 1. , high intensity electrometer and X
It is connected to a measuring device 2 consisting of a Y-1-G.

The first electric M Go 13a of the self-excited oscillation confirmation device of M I and C-
(This is a manometer 25υ＼ connected.

In FIG.
, - It is possible to apply external pressure by turning the arrow a to 1 and - C to 1.

Next, while applying a constant voltage of 0.5 uA to the excitable artificial membrane of the example using the DC power supply 19 of this self-excited oscillation confirmation device, the external pressure a was gradually increased using the manometer 25.
The presence or absence of self-sustained oscillation and the change in oscillation frequency when self-sustained oscillation occurs are measured.

The same measurements as in the example are carried out except that the excitable artificial membrane is replaced with that of the comparative example (a porous membrane on which only DOPH is rolled).

In Figure 1, the horizontal axis represents external pressure (cm t-120), the vertical axis represents oscillation frequency (1/'5ec), and the relationship between the two is plotted in the excitatory artificial A blower is installed for each membrane. In Fig. 2, the characteristics indicated by ■ or the example (
A porous membrane adsorbing a mixed lipid containing 20% by weight of glycolipids), and a special or comparative example shown in II.
There is C.

As is clear from Fig. 1, the excitable artificial membrane of the example has a short period with an oscillation wave number of about 0.62 (1/sec) even when the pressure is not external (Ocm H20). Self-oscillation occurs. Roughly speaking, the oscillation frequency of the excitable artificial membrane of the example increases as the vertical pressure increases. On the other hand, the @electrical artificial membrane of the comparative example requires an external pressure of 18 cmH2O to start short-period automatic oscillation, and the oscillation frequency in that case is about 0.57. It should be noted that the excitable artificial membrane of the comparative example does not exhibit the characteristic of increasing external pressure (C--accordingly, the oscillation frequency increases) as in the example.

Next, we measured the change in self-oscillation frequency when the direct current applied to the excitable artificial membrane of the example was gradually increased with the external pressure set to O. The axis (u A ) is taken, and the vertical axis is the oscillation frequency (+ , , ,
It is a diagram that plots the relationship between the two by taking =' sec ).

As is clear from FIG. 3, the excitable artificial membrane of the example exhibits an electric current of about 0.35 (1/sec) when a direct current of 0.3 u△ is applied to the artificial membrane. Oscillation layer;
f1. (Self-oscillation occurs, and the oscillation frequency increases in proportion to the increase in current. Therefore, the
It can be understood that it is possible to control the oscillation frequency by adjusting only the DC current without adding an additional pack.

1. Next, for the excitable artificial membrane of Example, 0.51 J△ of direct current was applied with the external pressure set to O for C self-excited oscillation. The oscillation waveform due to the potential difference between the standard electrodes 23a and 23b is measured. FIG. 4 shows the oscillation waveform C, with time plotted on the horizontal axis and the following potential difference plotted on the vertical axis.

As is clear from FIG.
Even if the potential difference suddenly increases, the subsequent decrease in potential difference is slow, and the excitable artificial membrane has the characteristic of being obtained from its unique oscillation waveform.

Next, we prepared a plurality of excitable artificial membranes with various amounts of glycolipids (glycolipids of formula (4)) in the mixed lipids. Fabricate using the same procedure as . In addition, the amount of mixed lipid adsorbed in each excitable artificial membrane is the same as in the example, total -C' 4 mg/c
It has been unified to m2. Thereafter, using the above-mentioned self-oscillation confirmation device, the vertical pressure at which self-oscillation can be started is measured for each excitable artificial membrane under the condition that the applied current is 0.5 uA.

FIG. 5 is a diagram in which the horizontal axis represents the amount of glycolipids mixed (wt%) and the vertical axis represents the oscillation starting pressure (cm H, ○), and the relationship between the two is plotted. In addition, the amount of glycolipid mixed is 0.
The oscillation start voltage of the excitable artificial membrane (the above-mentioned comparative example) is also plotted in C.

As is clear from FIG. 5, in the comparative example, the oscillation starting pressure is 9.
18 cm H20 was required, whereas in the case of Example 1 and Example 1 when the amount of glycolipid mixed was 1% by weight, the oscillation starting pressure was rapidly reduced to about 9 cm H20. When the content of 1 and 18 is 5% by weight, the oscillation starting pressure is about 7cmH2O (CI is about 7cmH2O, and the amount of glycolipid mixed is 10% by weight), the oscillation starting pressure is about 5cmH2O, and further,
It can be seen that if the amount of glycolipid mixture is 15 to 40% by weight (J), the oscillation starting pressure will be OcmH, ○ (no external pressure required).However, the illustration is omitted, or the glycolipid mixture is When the amount was set to 42.5% by weight, no self-supported oscillation was observed even if the oscillation initiation pressure was increased to at least 50 cm H20p.From these results, it was found that the glycolipid used when mixed with DOPH was In the case of the above, the mixing amount should be within the range of 1 to 40% by weight (from this, it can be seen that the external pressure at the beginning of self-sustained pulsation can be reduced. Especially If the mixing amount is within the range of 15 to 40% by weight and is 1, it can be seen that short-term self-sustained oscillation occurs without applying external pressure.

In the above, the embodiments of the excitable artificial membrane for bio-devices of the present invention have been described, but the present invention is not limited to the above-mentioned embodiments only, and the f! i
You can make various changes.

For example, in the example, the amount of adsorption of mixed lipids on the porous membrane is 4 m9/Cm2, and 1, 3 to 6 m9,/'
A similar effect could be obtained within the range of cm 2 . Note that the amount of mixed lipid adsorbed onto the porous membrane may be changed from 1 depending on the material and pore diameter of the porous membrane. The amount should be such that it is easy to change the degree of pore blocking due to the phase transition of the lipid.

In addition, in the above embodiment, the porous membrane is made of a specific material and has pores of a specific diameter (Millipore filter).
It is clear that the porous membrane composed of is not limited to this, and other membranes may be used depending on the design of the excitable artificial membrane.

1, and in the examples, the glycolipids were expressed as n in formula 1 (
M) Assuming that the glycolipid represented by the formula is sugar or curconu, 1.8: Even if it is a sugar or curconut sugar, the effect is similar to that of the example. You can expect.

(Effects of the Invention) As is clear from the above description, the excitable artificial membrane for biodevices of the present invention has a porous membrane ( Since the artificial membrane is constructed by adsorbing dioleyl phosphate to a porous membrane, it can be applied at a lower external pressure or at an external pressure L/ compared to the conventional excitable artificial membrane in which only dioleyl phosphate is adsorbed to a porous membrane. Self-oscillation occurs.

Therefore, it is expected that by using the excitable artificial membrane for bio-devices of the present invention, it will be possible to construct bio-devices that can be used in single-layer sensors and bio-devices.

[Brief explanation of drawings]

Figure 1 is a diagram used to explain the characteristics of the excitable artificial membranes of Examples and Comparative Examples; Figure 2 is a diagram showing the configuration of the self-assisted oscillation confirmation device for excitable artificial membranes; Figure 4 is a waveform diagram showing the state of self-assisted oscillation of the excitable artificial membrane of the example. Figure 5 is a diagram showing the dependence of the oscillation frequency on the applied current of the excitable artificial membrane of the example. FIG. 3 is a diagram showing the dependence of oscillation start pressure on the amount of mixed glycolipid. 1... Excitation attendant for bio-device -] - Membrane 3a... First electrolytic cell, 13b... Second electrolytic cell 5a... 100
mM Cβ aqueous solution 5b...5mM KCρ aqueous solution'? a, 17b, 23a, 23b - Standard electrode 9... DC power supply, 2]... Measuring device 25... Manometer, a... External pressure. Patent applicant: Oki Electric Industry Co., Ltd. Figure 5 shows the dependence of the oscillation initiation pressure of an excitable artificial membrane on the amount of glycolipid mixed.

Claims (2)

[Claims] (1) A biomolecule characterized by adsorbing a mixed lipid consisting of a dioleyl phosphate represented by the following structural formula [1] and a glycolipid represented by the following structural formula [2] onto a porous membrane. Excitable artificial membrane for devices (however, n in formula [2] indicates a positive integer value). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[1] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[2] (2) The glycolipid is a glycolipid represented by the following formula [3], and the amount of the glycolipid mixed in the mixed lipid is 1% by weight.
The excitable artificial membrane for biodevices according to claim 1, characterized in that the amount is within a range of 40% by weight or less. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[3]