JPS62151174A - Cell disintegration apparatus using high-voltage pulse - Google Patents

Abstract

PURPOSE:To enable the disintegration of bacterial cell, by filling a cell- containing solution between electrodes and imposing high-voltage pulse to the electrodes thereby exposing the bacterial cell to high electric field. CONSTITUTION:A pair of electrodes 1, 2 are closely attached to an insulating electrode case 3. A solution 8 containing cells is filled between both electrodes preventing the generation of voids between the electrodes and flowed along the direction of arrow. The electrodes 1, 2 are connected respectively to a pulse-output terminal 5 and a ground terminal 6 of a high-voltage pulse source 4 through lead wires 7l A high-voltage pulse having a pulse width of 0.1Xs-500sigma is applied to a high-voltage electrode to instantaneously generate a high electric field of >=3kV/cm in the solution.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a sterilizing device for destroying microorganisms, particularly bacteria, contained in a solution.

(Prior Art) Conventionally, well-known pressurization and heating methods have been used to sterilize microorganisms, especially bacteria, in a solution. A method using radiation irradiation is also used.

(Problem to be solved by the invention) However, the above-mentioned pressurization and heating method is
There is a problem in that the temperature must be kept at a temperature higher than °C, and the energy required for sterilization is large. In addition, methods using radiation irradiation require shielding from leakage radiation.
There is a problem that the device becomes large.

(Means for Solving the Problems) In order to solve the problems in the conventional techniques described above, the present invention provides an electrode for forming an equal electric field, such as a flat plate electrode to a flat electrode, or an electrode for forming an unequal electric field, such as a needle electrode. The idea is to fill a solution containing cells between the electrodes using a counter-plate electrode, or a flat-plate electrode with a needle and a flat-plate electrode with a needle, and apply a high-voltage pulse voltage between the electrodes to destroy the cells in the solution. This is the gist of the report.

(Function) According to the above-described means, a high electric field is instantaneously formed in the solution filling the space between the electrodes, and each cell in the solution is given a potential difference between both ends, causing an excessive current to flow through the cell membrane. Due to the flow, cell membranes are destroyed.

At this time, if a streamer discharge or arc discharge is generated in the solution by bringing the electrodes closer together or using unequal electrodes, the solution will instantly vaporize along the discharge path, creating an extremely strong shock wave. It will be done. At this time, cells are exposed to a high electric field and receive a strong shock wave, and the synergistic effect of the two causes them to be destroyed. When different types of cells exist in the solution, by selecting an appropriate pulse height and pulse width, it is possible to destroy only weak cells that cannot withstand the conditions.

According to this method, it is possible to sterilize with less energy than the pressurization and heating methods, and since shielding as in the radiation irradiation method is unnecessary, the device can be downsized.

(Examples) Hereinafter, several examples of the present invention will be sequentially described.

(First Example) A first example will be described with reference to FIGS. 1, 2, and 3. In FIG. 1, which shows a cross section of flat plate electrodes versus flat plate electrodes, the high voltage side flat plate electrode 1 and the ground side flat plate electrode 2 are connected to an electrode case 3 made of an insulating material (for example, polyvinyl chloride, Pyrex glass). They are in close contact with each other, and a solution 8 containing cells is filled between the two electrodes without creating a gap between the electrodes, and flows from the left side to the right side in the figure. The high-voltage side flat plate electrode 1 and the ground side flat plate electrode 2 are connected to a pulse output terminal 5 and a ground terminal 6 of a high-voltage pulse power source 4 via conductive wires 7, respectively. In the electrode arrangement described above, a high voltage pulse is applied to the high voltage side electrode. An example of a pulse voltage waveform is shown in FIG. The pulse voltage waveform is not limited to this, and square waves, sine waves, etc. may also be used.

The pulse width described in the claims column is the time from when the pulse voltage rises and reaches half its maximum value until it falls after reaching its maximum value and reaches half its value again. , that is, it is defined as the half width. For the sine wave, a waveform whose half cycle is 500 μS or less is used. In addition, the electric field strength described in the scope of claims is
It is defined as the value obtained by dividing the maximum value of the pulse voltage by the minimum value of the electrode spacing, that is, the maximum average electric field strength. By repeatedly applying pulse voltage, the cell destruction effect can be further enhanced. In Figure 3, a flat plate electrode to a flat plate electrode is used, with a spacing of 10 mm, and a pulse voltage (peak value 20 kV, voltage half width 200 μS, repetition frequency 2
This is an example in which yeast cells were destroyed by applying a frequency of 5 Hz.

It shows the relationship between the percentage of yeast that survived without being destroyed and the pulse voltage application time. Under these conditions, approximately 6
The yeast is almost completely killed in seconds. At this time 6
The temperature of the solution increased by about 15°C in seconds, and the yeast could be sterilized with less energy than sterilization by heating. Note that the electrode spacing and voltage conditions are not limited to those shown in this example, and may be selected in any manner within the range of the pulse width and electric field strength conditions described in the claims section.

(Second Example) A second example will be described using FIGS. 4 and 5. FIG. 4 shows a flat plate electrode with needles versus a flat plate electrode with needles. 10m
A needle electrode with a length of 2 mm is attached to each of the flat plate electrodes that face each other at an interval of m, and the needle electrodes face each other. The distance between needle electrodes is 6 mm. Pulse voltage (peak value 12 kV, voltage half width 200 μS,
A repetition frequency of 25 Hz) is applied. At this time, streamer discharge occurs at the tip of the needle electrode, generating a shock wave. Using the above electrode and pulse voltage, the destructive effect on yeast was investigated by varying the pulse voltage application time. The results are shown in Figure 5 with a Δ mark. Also, for comparison, the needle electrode was removed and the flat plate electrode vs. the flat plate electrode. The results of investigating the destructive effect on yeast when the same pulse voltage was applied (with an electrode spacing of 10 mm) are shown in FIG. 5 by circles.

When using flat plate electrodes versus flat plate electrodes, it was not possible to destroy all the yeast within 10 seconds due to insufficient pulse voltage peak value, but using flat plate electrodes with needles versus flat plate electrodes with needles. It has been found that when a shock wave is generated using this method, yeast can be completely destroyed in 10 seconds. Note that the electrode shape and dimensions may be selected in any manner within the range that satisfies the conditions of pulse width and electric field strength described in the claims section.

(Effect of the invention) That is, the gist of the present invention is the configuration described in the claims column, and by using pulsed high voltage with a short duration, electrolysis of the solution can be reduced, and high By utilizing the ability to generate an electric field, cells such as bacteria in a solution are exposed to a high electric field and effectively destroyed.

In addition, strong shock waves can be generated by causing streamer discharge or arc discharge, and it is possible to apply mechanical destructive force to cells in the solution, so the synergistic effect with a high electric field makes it more effective. Cells in solution can be destroyed. Furthermore, the peak value of the pulse voltage,
By adjusting the time width, it is possible to selectively destroy only weak cells that cannot withstand the voltage conditions.

[Brief explanation of drawings]

1, 2, and 3 show a first embodiment of the present invention. FIG. 1 shows a cross section of a cell destruction device and its connection to a pulse power source, and FIG. 2 shows a pulse voltage waveform, FIG. 3 shows the relationship between the pulse voltage application time and the percentage of surviving yeast. 4 and 5 show the second embodiment,
FIG. 4 is an explanatory diagram of a cross section of the apparatus, and FIG. 5 is an explanatory diagram of the cell destruction effect showing the relationship between the pulse voltage application time and the proportion of surviving yeast in the second embodiment. 1...High voltage side flat plate electrode 2...Grounding side flat plate electrode 3...Electrode case 4...High voltage pulse power supply 5...Pulse output terminal 6...Grounding terminal 7...Conducting wire 8. ...Solution containing cells 9...Flat electrode with needle 2;]""-F□.

Claims (1)

[Claims] A high voltage pulse with a pulse width in the range of 0.1 μS to 500 μS is applied to a solution containing cells such as bacteria in a suspended state, and a high electric field of at least 3 kV/cm or more is instantaneously applied to the solution. A cell destruction device that forms inside the cell and destroys cells.