JPH03150444A - Sample inspecting device - Google Patents

Abstract

PURPOSE:To take a measurement by statistical processing in a short time with high accuracy by making a horizontal scan plural times with a laser beam following one particle to be inspected. CONSTITUTION:This device is provided with detecting means 6-8 which detect one particle to be inspected passing a 1st irradiation position A, moving means 11 and 4 which move the laser beam L to the 2nd irradiation positions B-C after the detecting means 6-8 detect the passage, and scanning means 3 and 4 which makes a two-dimensional scan with the laser beam L in the flow direction of fluid as the particle to be inspected moves after the 2nd irradiation positions B-C. When the passage of one of particles to be inspected in the fluid at the 1st irradiation position A is detected, the laser beam L is moved to the 2nd irradiation positions B-C, from which a scan is made in the direction perpendicular to the flow and in the flow direction following the particles to be inspected; and obtained scattered light or fluorescent light is measured to analyze the object particle. Consequently, the measurement is performed in a short time with high accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to, for example, a flow cytometer, in which a laser beam or the like is irradiated to a test particle passing through a flow cell, and an optical signal from the test particle is detected. This invention relates to a sample testing device that analyzes the properties, structure, etc. of particles to be tested.

[Conventional technology] A flow cytometer is a cell suspension solution that flows at high speed.
In other words, it is a device that irradiates a sample liquid with, for example, a laser beam, detects a photoelectric signal from the scattered light, and elucidates the properties and structure of cells, and is used in fields such as cytochemistry, immunology, hematology, oncology, and genetics. used in

In conventional particle analysis devices used in flow cytometers, for example, a 200 um x 2
A laser beam or other light is irradiated onto test particles, such as blood cells, passing through a flow section with a minute rectangular cross section of 00 μm while being wrapped in a sheath fluid, and the resulting forward and side scattered light is used to Shape/size/
It is possible to obtain particle-like properties such as refractive index. Also,
For test particles that can be stained with a fluorescent agent, important information for analyzing the test particles is obtained by detecting the fluorescence of the test particles along with side scattered light in a direction almost perpendicular to the irradiation light. be able to.

Conventionally, in this type of device, the size of the test particles is measured by irradiating the test particles flowing in the fluid with a fixed laser beam and detecting the forward scattered light from the laser beam with a photodetector. are doing. However, the position of the test particles in the flow section varies in the direction perpendicular to the flow, and the center position of the test particles deviates from the intensity distribution of the laser beam, changing the amount of light irradiated to the test particles, resulting in scattered light. The intensity is not constant, and it is inevitable that the measurement will contain errors.

By adopting the sheath flow method, this drawback can be compensated for considerably, but it is necessary to accurately align the center of the flow section and the center of the laser beam intensity distribution in advance (subtle adjustment operations are essential. In order to eliminate the need for this adjustment operation and to prevent variations in the position of the particles to be detected flowing in the fluid from affecting the scattered light intensity, the laser beam is directed in a direction perpendicular to the flow of the particles to be detected. A specimen testing device that performs similar detection by scanning has been proposed.This scanning is performed using an acousto-optic device (AOD), and a frequency-modulated voltage is applied to the acousto-optic device to change the deflection angle of the laser beam. I'm letting you do it.

[Problems to be Solved by the Invention] However, in the conventional example described above, there is a limit to the scanning speed of a laser beam using an acousto-optic element, so high precision is achieved by increasing the number of scans per particle. In order to measure , the flow rate of the particles to be tested must be slowed down. However, in order to improve the measurement accuracy, statistical processing of measuring a large number of test particles is required, so if the flow rate is slowed down, the measurement takes a considerable amount of time. In addition, since the position of each particle to be detected relative to a single particle is not detected and is simply scanned in a direction perpendicular to the flow at a constant cycle, even if the number of scans is increased, the center of the particle to be detected can be accurately located. The probability of being able to scan the laser beam is low.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sample testing device that eliminates the above-mentioned drawbacks and enables highly accurate measurements in a short period of time by scanning a laser beam.

[Means for Solving the Problems] In order to achieve the above object, the specimen testing device according to the present invention scans and irradiates test particles in a fluid with a light beam, and measures the obtained optical signal. In a sample testing device that analyzes test particles using
a detection means for detecting that the light beam has passed through the irradiation position; a moving means for moving the light beam to a second irradiation position after the detection means passes through the irradiation position; The apparatus is characterized by comprising a scanning means for two-dimensionally scanning a light beam along the flow direction of the fluid.

[Operation] When the sample testing device having the above configuration detects passage of one test particle through the first irradiation position with respect to the test particles in the fluid, it directs the laser beam to the second irradiation position. move,
From this second irradiation position, the laser beam is scanned in a direction perpendicular to the flow and in the flow direction following the target particle, and the resulting scattered light or fluorescence is measured to analyze the target particle.

[Example] The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a side view of an embodiment according to the present invention, and FIG. 2 is a sectional view showing a laser light source 2 between a flow cell 1 having a flow section 1a through which test particles flow at high speed and a laser light source 2. On the optical path L1 of the laser beam L emitted from
An acousto-optic element 3.4 is provided, and the laser beam L is directed horizontally by the acousto-optic element 3 to the acousto-optic element 4.
The image is scanned in the vertical direction. A stopper 5 is provided on the optical path 1,1' of the laser beam 1 when the acousto-optic element 3.4 is not activated. Further, on the extension of the shortest optical path L2 connecting the acousto-optic element 4 and the flow cell 1, a stopper 6,
A condensing lens 7 and a photodetector 8 are provided, and on an optical path L3 that is deflected downward from the optical path L2 by the acousto-optic element 4, a narrow stopper 6 and a condensing lens 9 are provided in common with the optical path L2.
, photodetectors 10 are sequentially arranged. The acousto-optic element 3.4 and the photodetector 8 are connected to a control circuit 11, and the output of the photodetector 10 is connected to a signal processing circuit 12.

The laser beam L emitted from the laser light source 2 passes through the acousto-optic element 3.4 and irradiates the test particles flowing through the flow section la of the flow cell 1. The forward scattered light at the irradiation position A by the test particles on the optical path L2 is collected by the condensing lens 7 via the stopper 6, is received by the photodetector 8, and is irradiated from the irradiation position B on the optical path L3. The forward scattered light between the positions C is collected by the condenser lens 9 and received by the photodetector lO.

The output of the photodetector 8 is connected to a control circuit 11, and the control circuit 11 changes the deflection angle of the acousto-optic element 3.4 according to this output, that is, the magnitude of the amount of received light. The output of the photodetector 10 is input to a signal processing circuit 12, and this signal is processed into necessary information about the particles to be detected. Note that the acousto-optic element 3
．． 4, the laser beam L not deflected by stopper 5
The laser beam L that is blocked by the stopper 6 and is not scattered by the test particles even if it enters the flow cell 1 is blocked by the stopper 6 and does not directly enter the photodetector 8.10.

As described above, the polarization directions of the acousto-optic elements 3.4 are perpendicular to each other, and FIGS. 3(a) to 3(a) show views looking from the laser light source 2 side to the flow cell 1 side. When the laser beam L is deflected only by the acousto-optic element 3, Fig. 3 fa
), scanning is performed in the horizontal direction at the irradiation position A, and scanning is performed in the vertical direction when deflected only by the acousto-optic element 4. When deflecting the acousto-optic elements 3 and 4 in combination, if the deflection period of the acousto-optic element 4 is set to be longer than that of the acousto-optic element 3, the laser beam ■- is shown in FIG. 3(b). For example, it is possible to scan from the Iq irradiation position A to the irradiation position C in a zigzag pattern.

At the irradiation position A, the laser beam L is
If horizontal scanning is performed as shown in FIG.
It is detected that the

After this detection, the acousto-optic element 4 is controlled by the control circuit 11 to move the irradiation position of the laser beam L from the irradiation position A to the irradiation position B, and as shown in FIG. The same test particle is scanned from irradiation position B to irradiation position C.If the scanning time is set according to the flow velocity of the test particle, one test particle will move from irradiation position B to irradiation position C. The center of this test particle can be scanned multiple times until reaching C.

When the laser beam L has finished scanning to the irradiation position C by following one particle to be inspected, the control circuit 11 controls the acousto-optic element 4 to return the laser beam L to the irradiation position A. Then, by repeating the detection and follow-up scanning of another test particle again in the same manner, statistical processing can be performed on a large number of test particles.

In reality, there are errors in the flow velocity and scanning cycle time of the particle to be inspected, and even if the laser beam L is scanned multiple times before reaching the irradiation position B or C, the laser beam L may not be centered on the particle to be inspected. The probability of being irradiated is not very high. Therefore, we set the scanning velocity component in the flow direction to be slightly slower than the flow velocity.
Either start scanning a little earlier than the target particle reaches the irradiation position B, or set the scanning velocity component in the flow direction a little earlier and slightly slower (if you start scanning, the irradiation position of the laser light source L and the target particle Since the relative positions of the particles are changed during scanning, the laser beam L is irradiated to the center of the target particle with a higher probability, improving measurement accuracy.

[Effects of the Invention] As explained above, the specimen testing device according to the present invention makes the laser beam follow one sample particle and performs horizontal scanning multiple times, so the statistical processing is performed in a short time. Highly accurate measurements can be made in a short amount of time.

[Brief explanation of the drawing]

The drawings show an embodiment of the specimen testing device according to the present invention, in which Fig. 1 is a side view, Fig. 2 is a plan view, and Fig. 3 (a) to fc).
FIG. 2 is an explanatory diagram of the irradiation position of the laser beam. Symbol l is a flow cell, 2 is a laser light source, 3.4 is an acousto-optic element, 5.6 is a stopper, 7.9 is a condensing lens, 8
．． 10 is a photodetector, 11 is a control circuit, and 12 is a signal processing circuit.

Claims (1)

[Scope of Claims] 1. In a sample testing device that analyzes a sample particle by scanning and irradiating a sample particle in a fluid with a light beam and measuring the obtained optical signal, a detection means for detecting that the light beam has passed through the first irradiation position, a moving means for moving the light beam to a second irradiation position after the detection means passes the light beam, and a particle to be detected after the second irradiation position. a scanning means for two-dimensionally scanning a light beam along the flow direction of the fluid as the body moves. 2. The specimen testing apparatus according to claim 1, wherein the scanning means includes two acousto-optic elements disposed orthogonally in the optical path of the light beam. 3. The specimen testing apparatus according to claim 1, wherein the detection means detects based on the amount of received optical signal from the light beam irradiated at the first irradiation position.