JP3101450B2 - Particle measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the technical field of transporting particles in a fluid.

[0002]

2. Description of the Related Art Various methods have been developed for transporting minute particles such as cells and carrier particles in a fluid. As an example, there is a method of transporting particles using the force exerted by an electric field. Specifically, those utilizing electrophoretic force and those utilizing dielectrophoretic force are known.

[0003]

When the electrophoretic force is used, the distance between the electrodes becomes longer when carrying out long-distance transport, and it is necessary to apply a high voltage of, for example, several tens of KV. This poses a problem of danger and an increase in the size of the device.

In addition, when utilizing the dielectrophoretic force, if there is a particle other than the position where the action force is applied by applying an electric field, there is a problem that the force due to the opposite electric field is apt to be exerted, and it is difficult to continuously transport the particles. .

It is an object of the present invention to provide a particle measuring apparatus which improves the above-mentioned conventional method, can stably convey particles, and enables highly accurate measurement.

[0006]

A particle measuring apparatus according to the present invention for solving the above-mentioned problems has a measuring section provided in the middle of a flow path through which particles are conveyed, and generates an electric field having a non-uniform density. A plurality of electrodes are arranged along the flow path, particles are conveyed along the flow path by the action of the electric field, and the conveyed particles are measured by the measurement unit.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a particle measuring apparatus according to an embodiment of the present invention will be described with reference to the drawings. The particle measuring apparatus according to the present embodiment is for flowing blood cells in a blood sample, for example, and optically measuring the blood cells to count and analyze the blood cells.

FIG. 1 is a configuration diagram of an apparatus according to an embodiment. In the figure, 10 is a transparent substrate, 11 is a transparent substrate having a groove formed, and both are joined. Reference numeral 1 denotes a flow path for flowing a sample liquid such as a blood sample. Electrodes 21 (21 ') to 25 (25') are arranged on the lower surface of the flow path, and form five electrode pairs. Reference numeral 7 denotes a light source such as a laser for applying irradiation light to the measuring unit in the flow path, and 8 denotes a detector for detecting light from the measuring unit, and these constitute a measuring optical system. 9 is a particle analysis unit having a computer and the like.

As the transparent substrate 10, for example, Pyrex glass is preferable. The transparent substrate 11 is formed by processing a resin by, for example, press working or the like to form a groove serving as the flow path 1. Alternatively, a flow channel may be formed by etching the transparent substrate 11 using glass. The flow path diameter is 10
The diameter is preferably set to 1000 μm according to the size of the particles to be handled. In this embodiment, the size is 50 μm × 170 μm. The electrodes are formed on the transparent substrate 10 by photolithography. The length of each electrode is 200 μm, and the gap between the paired electrodes is 50 μm at the narrow portion and 150 μm at the wide portion.

FIG. 2 is a diagram showing the configuration of an electric system according to this embodiment. 4 is a high frequency oscillator, 5 is a low frequency oscillator, 6 is a switch, and the switch 6 is connected to the electrode 2. The high-frequency oscillator 4 generates an AC high frequency of 1 kHz to 10 MHz. The alternating current is a triangular wave, a trigonometric function wave, a rectangular wave, or the like. The low-frequency oscillator 5 generates a rectangular wave having a frequency of 1 / t, and the switch 6 controls the electrodes 2 according to the sign of the rectangular wave.
Switch the voltage application to. Here, t is the time required for particles in the flow path to move from the upstream end to the downstream end of each electrode when a high frequency is applied to the electrode 2. A set of electrodes 22 (22 ') and 24 (24') is provided at every time t by the switch 6 based on the output of the low frequency oscillator 5,
Electrodes 21 (21 '), 23 (23'), 25 (25 ')
Are switched so that a high-frequency voltage is alternately applied to the set of.

The lines of electric force generated when a voltage is applied to the electrode pairs are non-uniform electric fields that become denser as the distance between the electrodes goes from wide to narrow. Therefore, the particles in the flow path receive the acting force in the direction in which the lines of electric force are dense, that is, in the right direction in the drawing, and are conveyed rightward. In FIG. 2, the electrodes 21 (2
The state of the lines of electric force generated when a voltage is applied to the set of 1 '), 23 (23'), and 25 (25 ') is indicated by a dotted line. Each electrode is arranged so that the lines of electric force generated by each pair of electrodes partially overlap the range of the next pair of electrodes, so that the particles in the flow path are stably transported one after another without stopping movement. Is done.

If the edges of each electrode are formed at an acute angle, the electric field tends to concentrate particularly at the end where the electrode gap is narrow, so that the edge of the electrode is rounded or the shape of the electrode is reduced. Is slightly expanded toward the center of the flow path, which is preferable because the electric lines of force at the center of the flow path become denser.

In a measuring optical system comprising a light source 7 and a detector 8, light is emitted to a measuring section in the flow path, and scattered light and fluorescence emitted from particles passing through the measuring section are measured by the detector 8. The particle analysis unit 9 calculates the particle count and analyzes the type and properties of the particles based on the output from the detector 8.

FIG. 3 shows a modification of the apparatus of the above embodiment. Electrodes similar to those in the above embodiment are formed on both the upper surface and the lower surface of the flow path. At this time, the direction of the electrodes can be reversed between the upper surface and the lower surface to generate a reverse electric field line distribution. Here, by selecting an electrode on one of the surfaces and applying a high-frequency voltage to the electrode in the same manner as in the above-described embodiment, it is possible to switch the transport direction of the particles.

FIG. 4 shows another modification. The electrodes were alternately dispersed and arranged on the upper surface and the lower surface of the flow path to facilitate wiring.

FIG. 5 shows another modification. By providing the electrode in the middle of the channel, the particles were allowed to pass between the electrode pairs where the electric field was strongest.

[0017]

According to the present invention, particles can be stably transported with a simple configuration, and highly accurate particle measurement can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a configuration diagram of an electric system according to an embodiment.

FIG. 3 is an explanatory diagram of a modified example.

FIG. 4 is an explanatory diagram of another modified example.

FIG. 5 is an explanatory diagram of another modified example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flow path 4 High frequency oscillator 5 Low frequency oscillator 6 Switching device 7 Light source 8 Detector 9 Particle analysis part 10, 11 Transparent substrate 21 (21 ') thru 25 (25') Electrode

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-47-44365 (JP, A) JP-A-48-16260 (JP, A) Hiroo Kumagai, 3 others, “Particle Accelerator”, Showa 41 Year, first edition, p. 9-17 Hiroo Kumagai, "Accelerator", Kyoritsu Shuppan Co., Ltd., 1982, 2nd edition, p. 137− 141 (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01N 15/00-15/14

Claims (4)

(57) [Claims] 1. A method according to claim 1, further comprising a measuring unit provided in the middle of the flow path through which the particles are conveyed, and a plurality of electrodes for generating an electric field having a non-uniform density arranged along the flow path. Characterized in that the particles are conveyed along the flow path, and the conveyed particles are measured by the measuring section. 2. The electrode according to claim 1, wherein a plurality of electrode pairs whose gap gradually changes from a narrow gap to a wide gap are arranged along the flow path. Particle measuring device. 3. The particle transport device according to claim 2, further comprising: a high-frequency oscillator for applying an AC voltage to the electrode pairs; and a switch for switching voltage application to the plurality of electrode pairs. 4. The particle measuring apparatus according to claim 1, wherein the measurement is performed by optically measuring the particles in the measuring section.