JPH011937A - Photodetection electrophoresis device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photodetection type electrophoresis device that detects fluorescence or scattered light, and particularly to a DNA base sequencing device.

[Conventional technology]

As a device for electrophoretic separation and detection of fluorescently labeled DNA Att.
A method based on spot irradiation point detection is known, as described in Japanese Patent Application Laid-Open No. 60-220860.

For simultaneous measurement of multiple samples, two-point irradiation/scanning with a point detection unit can be considered, but a line irradiation line detection method has been proposed as an alternative method (Japanese Patent Laid-Open No. 61-62843).
As shown in Figure 1, this method involves entering a laser beam from the side into a gel electrophoresis plate with multiple migration paths, irradiating it in a straight line at a certain distance from the migration starting point, and passing through that point. The fluorescently labeled DNA is excited. The emitted fluorescence is imaged on an image amplifier through a filter and a condensing lens, and after being amplified, it is detected with a diode array or a TV camera. This measuring device is geometrically configured so that the central horizontal axis of the diode array or TV camera is on the plane formed by the laser optical axis and the light receiving optical axis.

[Problem that the invention seeks to solve]

In the above conventional technology, the excitation light and the center horizontal axis of the measurement diode array or two-dimensional sensor are kept parallel to each other by the laser unit and the light receiving measurement unit (
(including a part of the sensor), but there was no special adjustment function. Typically, the laser beam is deflected by 90° using a mirror and illuminates the gel panel. The laser beam needs to be set so that the migration path length is constant over the entire measurement area of the gel plate. This can be achieved automatically by attaching the electrophoresis plate, but due to individual differences in gel preparation, fine adjustment is required. Therefore, the mirror can be swung horizontally and vertically to adjust the laser beam path. It is desirable that this irradiation light beam be parallel to the measurement system, i.e., the center line of the line sensor or the horizontal readout line of the two-dimensional sensor. However, the horizontal axis of the two-dimensional sensor in a diode array or TV camera is not necessarily parallel to the laser beam (this causes a decrease in sensitivity and deterioration of resolution. The purpose of the present invention is to solve the above problem. It was done in order to

[Means for Solving the Problems] The above object is achieved by rotatably configuring the stand holding the detection unit equipped with a diode array or two-dimensional sensor.

[Effect]

By making the detection part rotatable, it is possible to make the excitation light and the horizontal axis of the array sensor or two-dimensional sensor in the detection part parallel to each other without deflecting the laser beam with a mirror or rotating the electrophoresis plate. can.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. The device is a laser light source3. 5. Electrophoresis separation unit having a migration plate 1 and a buffer tank 2, a filter and a lens. A detection unit having a two-dimensional sensor 7, a frame memory 8, and a computer 9. It consists of a data processing section having an output device 10. In this embodiment, a case will be described in which a two-dimensional sensor 7 is used as the detection section, but a TV camera may be used instead. The laser beam 6 is transmitted through the mirror 4. It passes through a focusing lens (not shown) and enters the gel 1 from the side.

Usually, the center of the electrophoretic plate 1 is selected as the beam focusing point so that the beam incident on the electrophoretic plate 1 is focused narrowly over a wide area. The irradiation angle is set so that the length of each migration path is constant. Various electrophoretically separated substances pass through the irradiation section. If the detector does not have position detection in the electrophoresis direction, the separation detectability is determined by the laser beam width. The length of the gel irradiation area is 20 cm, and the laser beam 6
The beam diameter is the smallest at the center, and the beam diameter at the entrance is equal to the gel thickness (0, 5 mm m −= 0, 3
mm) or less. Due to lens aberrations and light interference, the actual light beam is O-5 at the entrance.
The limit is 0 and 3 mm in the central part of rn m r. In other words, the separation detection potential for this status is 0.3 to 0.4 m.
m. However, if the light-receiving optical system has high resolution, it is possible to obtain high separation and detection performance as a detection system regardless of the excitation light width.

In fact, the optical resolving power of the example is smaller than 0.1 mm mm - the laser beam width, and the resolving power is less than the laser line width.

When the apparatus is assembled in the usual way and the fluorescence image 13 is measured, the result is as shown in Figure 2, but they do not match, and the horizontal axis of the measurement system, that is, the central horizontal line 12 of the monitor image 15, the observation fluorescence image 13, and the irradiation axis do not necessarily match. do not. If adjustment is attempted using only the mirror, there will be an inconvenience that the image will be largely deviated from the center of the screen, as shown in Figure A19114. Furthermore, the migration distance may deviate little by little in each migration path, and if the irradiation angle is adjusted to compensate for this, the deviation may occur even further. In low-resolution measurements, a region is set around the center, and the signals that enter this region are integrated vertically and used, so there is no problem even if the horizontal axis of light reception and the axis of irradiation are misaligned. However, when attempting to measure with a resolution close to the resolution limit of the optical system, it is necessary to extract a signal corresponding to one scanning line of a TV monitor. If the irradiation axis and the horizontal axis of the measurement system do not match, the signal will only be obtained from a small area.

Therefore, in this embodiment, by aligning both axes using a light-receiving unit rotation mechanism provided for the mount, a signal with high positional resolution in the electrophoresis direction can be obtained over the entire irradiation length.

〔Effect of the invention〕

As explained above, in the present invention, first, the irradiation system is set so that the migration path length is constant, and then the irradiation axis and the horizontal axis of the light receiving system can be aligned, so that high positional resolution measurement can be performed.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an embodiment of the present invention, and FIG. 2 is a diagram showing a measured image on a two-dimensional sensor display device. DESCRIPTION OF SYMBOLS 1... Electrophoresis plate, 2... Buffer tank, 3... Laser light source, 4... Mirror, 5... Filter and lens, 6... Laser beam, 7... Two-dimensional sensor, 8 ... Frame memory, 9... Calculator, 10.
... Output device, 11... Stand with rotation function, 12...
Central horizontal line, 13... Observed fluorescent line image, 14... Fluorescent line image during mirror adjustment. 15...Monitor image//-

Claims (1)

[Claims] 1. In an electrophoretic separation and detection device that has an excitation laser light source and an optical two-dimensional sensor or licensor that detects light generated by irradiation with the excitation laser light, these sensors or sensors are located around the measurement optical axis. 1. A photodetection type electrophoresis device characterized in that a detector incorporating a detector is configured to be rotatable.