JP3492587B2 - Electrophoresis device with plunger detection function - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophoretic device, and more particularly to an electrophoretic device suitable for a device which requires a work of pressurizing a syringe to inject a gel serving as a separation medium into a capillary.

[0002]

2. Description of the Related Art An electrophoresis apparatus using a capillary that needs to inject a gel serving as a separation medium has conventionally used a method of injecting the gel into the capillary from a syringe. The syringe is pressurized by a driving unit controlled by a computer. The drive unit is attached to a slider that operates on a ball screw, and the pulse motor rotates the ball screw to operate the drive unit. The amount of movement of the drive unit can be confirmed by a linear encoder. When actually injecting gel into the capillary, the force for pressing the syringe is controlled by the value of the current applied to the pulse motor, and the amount of gel injected is adjusted by the drive time of the motor.

When the amount of gel remaining in the syringe becomes low and it becomes necessary to replenish the gel, first the drive unit is moved upward to secure a sufficient working space, and then the syringe is removed from the apparatus. , Refilling the gel. After reattaching the syringe filled with gel to the device, visually confirm the positions of the drive unit and the plunger that had been moved upward first, while inputting the necessary movement amount into the computer and gradually driving. The part is adapted to the position of the plunger of the syringe. If you do not perform this operation and start gel injection in a state where the drive unit and the plunger of the syringe are separated, the amount of gel injected into the capillary will be insufficient for the time required for the drive unit to reach the plunger. Become.

[0004]

In the above-mentioned prior art, after the syringe is attached and detached, the gel injection operation is started after the drive portion is aligned with the plunger position of the syringe by visual confirmation of the position and manual operation. . that is,
The amount of gel injected into the capillary is adjusted by the time that the motor is driven, so if the position of the drive unit and the plunger of the syringe are far apart, the time required for the drive unit to reach the plunger This is because the amount of gel to be injected into the capillary is insufficient by that much. The positioning of the drive unit and the plunger requires delicate control, and if the operation is erroneous, the syringe may be strongly pressurized. Further, the work of aligning the drive unit and the plunger is a factor that prolongs the setup time of the apparatus.

It is an object of the present invention to provide an electrophoretic device capable of continuous operation without requiring manual alignment of the drive unit and the plunger even after the syringe is attached and detached for gel replenishment or the like. To do.

[0006]

SUMMARY OF THE INVENTION The present invention provides an electrophoresis apparatus having a capillary and a detector for optically detecting a sample component introduced into the capillary and electrophoretically separated, and a gel held in a syringe. It has a drive unit for injecting into the capillary by lowering the plunger, and a control unit for controlling the operation of this drive unit, and is characterized in that the position of the plunger is detected by lowering the drive unit.

Desirably, the drive unit detects a motor for generating power, an actuator for converting a rotational torque of the motor into a propulsive force, a drive unit for applying a force in contact with the plunger, and a movement amount of the drive unit. And a moving speed of the driving unit is obtained from the moving amount of the driving unit read by the encoder,
If the obtained moving speed is smaller than the predetermined threshold value, it is determined that the drive unit has contacted the plunger.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic diagram of an electrophoretic device having a gel injection mechanism according to an embodiment of the present invention. The capillary array 118 is composed of at least one or more capillaries, and has one end inserted into the block 116 and the other end integrated with an electrode connected to the power supply 121.

Before the measurement, the capillary array 118 is filled with a gel serving as a separation medium from the block 116 side. An injection syringe 113 for injecting gel into the capillary array 118 and a refill syringe 114 for replenishing the injection syringe with gel are attached to the block 116. In the block 116, a first syringe that connects the refilling syringe 114 and the injecting syringe 113 to each other is provided.
Channel, the injection syringe 113 and the capillary 11
8 is connected to the second flow path, and a branch path is provided in the second flow path to the buffer reservoir 126 that becomes the ground potential during electrophoresis. Also,
The refilling syringe 114 and the injecting syringe 113
A check valve 115 is inserted between the flow paths communicating with each other to prevent backflow into the refill syringe 114. The refilling syringe 114 and the injecting syringe 11
3 is a drive unit 17 controlled by the control unit 12,
Each is pressurized by 18. Linear encoders 19 and 110 are attached to the drive units 17 and 18, respectively, and position information of the drive units is transmitted to the computer 11 via the control unit 12 by reading the values of the linear encoders. As the power source for the drive units 17 and 18, for example, DC motors 13 and 14 are used.

The capillary array 118, after being filled with gel, moves to the sample container 122, sucks the sample by an electric action, and then moves to the buffer tank 123. When a voltage is applied to the inside of the buffer tank 123 through the electrode portion of the capillary, an electric field is generated in the capillary, and the introduced sample starts electrophoresis. The separated sample can be detected in the excitation light irradiation unit 117, which is irradiated with the excitation light, due to the difference in the migration speed of the introduced sample due to the molecular weight and the like.
A fluorescent substance is attached to the sample in advance,
By irradiating the excitation light irradiation section 117 with the excitation light from the light source 119, fluorescence is generated from the sample to which the fluorescent substance is attached in advance. The detector 120 detects the fluorescence generated from this sample. In particular, the sample is deoxyribonucleic acid
In the case of (DNA), if a specific fluorescent substance is attached depending on which of adenine, guanine, thymine, and cytosine the terminal is, the base at the end of the sample can be identified from the wavelength of the detected fluorescence. it can. When the analysis is completed, the capillary array 118 is replaced with a new gel by the injection syringe 113, and the next measurement is started again.

A flow chart of the gel injection work is shown in FIG. When a gel injection command is issued from the computer 11 (step 201), the controller 12 first executes the initial operation of the gel injection unit (step 202) and closes the buffer valve 124 (step 203). afterwards,
The drive unit 17 descends to automatically detect the position of the plunger 111 of the injection syringe 113 (step 204).
Injection side linear encoder 19 when the position of the plunger is detected
The amount of residual gel in the injection syringe 113 is grasped from the value of (step 205). At this time, the injection syringe 1
If the gel in 13 is insufficient, the gel refilling operation from the refilling syringe 114 to the injecting syringe 113 is executed prior to the gel injection. The principle of automatically detecting the position of the plunger 111 when the drive unit 17 descends will be described later.

The gel refilling operation is executed as follows.
First, the injection-side drive unit 17 moves to the position of the plunger when the gel in the injection syringe reaches the specified amount (step 211). Next, the replenishment side drive unit 18 descends to automatically detect the position of the plunger 112 of the replenishment syringe 114 (step 212). From the value of the replenishment side linear encoder 110, the remaining amount of gel in the replenishment syringe 114 is determined. Understand (step 213). At this time, if the remaining amount of gel in the refilling syringe 114 is sufficient, pressurization of the refilling syringe 114 is started to start gel refilling (step 214). At this time, most of the gel extruded from the refill syringe 114 and flowing into the block 116 is
Due to the difference in flow path resistance, the plunger 111 of the injection syringe 113 is pushed into the injection syringe 113 while being pushed up instead of the capillary. When the amount of gel in the injection syringe 113 reaches a specified amount, the plunger 111
Collides with the injection side drive unit 17, and when the value of the encoder 110 of the drive unit 18 stops changing, it is determined that the drive unit 18 has stopped, and the gel replenishing operation is completed (step 2
15). When the gel refill is complete, to release the pressure,
The replenishment side drive unit 18 moves up and waits until the next command comes (step 216). If the amount of remaining gel in the refill syringe 114 is insufficient, a message indicating that the amount of remaining gel is insufficient is displayed on the screen of the computer 11 and the gel is replenished in the refill syringe 114. Will restart the process (step 218).

When the remaining amount of gel in the injection syringe 113 is sufficient or after the gel is replenished, the injection side drive unit 17 starts to pressurize the injection syringe 113 and inject the gel into the capillary 118. Starts (step 20)
6). At this time, the check valve 115 is the refill syringe 114.
To prevent backflow of gel into the
Since the gel is closed, the gel extruded from the injection syringe 113 can only flow out through the capillary 1
It will run into 18. When a certain amount of gel is filled, the injection side drive unit 17 stops the pressurization (step 20).
7) Then, move upward and wait to release the pressure (step 208). Then, after the buffer valve 124 is opened (step 209), a voltage is applied to the electrode portion of the capillary and the electrophoresis is started (step 21).
0).

Next, the principle of operation of the linear encoder will be described with reference to FIGS. FIG. 3 is a schematic diagram of the linear encoder, and FIG. 4 is a schematic diagram of the structure of the linear encoder. A film 31 having slits 32 formed in a straight line is attached to the drive unit and passes through an optical detection unit 33 attached to the apparatus body when the drive unit moves. The optical detection unit 33 uses a light emitting diode 42 as a light source.
Light source unit 4 including a lens 43 for producing parallel rays
It is composed of 1 and an optical sensor 44, and has a mechanism capable of optically counting the number of slits passing between the two. The control unit 12 can recognize the amount of movement of the drive unit per unit time (moving speed of the drive unit) by periodically checking the number counted by the detection unit 33, and also determine the current position from the total movement amount. I have a grasp.

Next, the principle of automatically detecting the position of the plunger by lowering the drive unit described in the above embodiment will be described. FIG. 5 is a moving speed diagram of the drive unit. The vertical axis represents the moving speed of the drive unit, and the horizontal axis represents time. In the figure, a period T1 is a period from the start of the movement of the drive unit to the time point t1 when the drive unit contacts the plunger,
The period T2 is a period from time t1 when the drive unit contacts the plunger to time t2 when the drive unit stops. From when the drive unit starts moving until it contacts the plunger,
That is, when the drive unit is moving above the plunger, only its own weight acts as a main load, so that the drive unit moves at a substantially constant speed (51). Next, at t1, the drive unit comes into contact with the plunger, and further attempts to move the plunger in the direction of pushing it in place a large load on the drive unit. When a DC motor is used as the power source for the drive,
Since the rotation speed changes depending on the degree of load, if the drive unit comes in contact with the plunger (52) and pushes the plunger further from there, the internal pressure of the syringe will increase and the load on the drive unit will increase. Decreases sharply (53). Eventually, if a load exceeding the limit of the motor is applied to the drive unit, the motor will be locked and the drive unit will stop at that point at time t2 (5
4). The control unit 12 can detect a change in the moving speed of the drive unit by checking the value of the linear encoder in a constant cycle. In the present embodiment, using the above principle, the moving speed of the drive unit is obtained based on the value from the linear encoder, and when the moving speed becomes smaller than the set threshold value, the drive unit contacts the plunger. Then, the position of the plunger is detected from the encoder value at that time. Note that, in FIG. 5, the change in the moving speed of the drive unit in the period T2 is shown as a straight line for convenience of description, but the present invention is not limited to this, and the characteristics of the motor used as the power source of the drive unit are not limited thereto. It goes without saying that the change in moving speed is determined accordingly.

According to one embodiment of the present invention based on the above principle, the position of the plunger is automatically detected by lowering the driving unit. As a result, even when the syringe is attached and detached for gel refilling work, the work of manually aligning the drive unit and the plunger is unnecessary, and continuous operation of the device is possible.

Further, the setup work before the measurement of the device is simplified, so that the setup time can be shortened.

In the above embodiment, the contact of the drive unit with the plunger is determined based on the value from the encoder. However, it is determined based on the change in the rotation speed of the DC motor used as the power source. May be. In this case, a similar result can be obtained if the vertical axis of the moving speed diagram of the drive unit shown in FIG. 5 is replaced with the rotational speed of the DC motor from the moving speed of the drive unit.

[0019]

According to the present invention, it is not necessary to manually position the drive unit and the plunger even after the syringe is attached and detached for gel replenishment, and continuous operation can be started.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an electrophoretic device including a gel injection mechanism.

FIG. 2 is a flow chart of a gel injection work.

FIG. 3 is a schematic diagram of a linear encoder.

FIG. 4 is a structural schematic diagram of a linear encoder.

FIG. 5 is a moving velocity diagram of a drive unit.

Front page continuation (56) Reference JP 2001-242140 (JP, A) JP 11-230936 (JP, A) JP 5-196603 (JP, A) JP 2000-6989 (JP, A) ) Japanese Patent Laid-Open No. 10-293090 (JP, A) Japanese Patent Laid-Open No. 2000-162183 (JP, A) Special Table 11-511555 (JP, A) Special Table 2002-514309 (JP, A) (58) Fields investigated ( Int.Cl. ⁷ , DB name) G01N 27/447 G01N 1/00 G01N 35/06

Claims (8)

(57) [Claims] 1. An electrophoretic device having a capillary and a detector for optically detecting a sample component introduced into the capillary and electrophoretically separated, and a syringe for holding a gel to be injected into the capillary. It has a drive unit that injects the gel held in the syringe into the capillary by lowering the plunger, and a control unit that controls the operation of the drive unit, and detects the position of the plunger by lowering the drive unit. An electrophoretic device characterized by detecting the remaining amount of gel in the syringe. 2. The driving unit according to claim 1,
At least a motor that generates power, an actuator that converts a rotational torque of the motor into a propulsive force, a drive unit that contacts the plunger to apply a force, and a linear encoder that detects a movement amount of the drive unit are provided. An electrophoretic device characterized by: 3. The driving unit according to claim 2, wherein a moving speed of the driving unit is obtained from a moving amount of the driving unit read by the encoder, and when the obtained moving speed is smaller than a predetermined threshold value, the driving unit is An electrophoretic device, characterized in that it is determined that the contact with the plunger. 4. The control unit according to claim 2, wherein the control unit determines the positional relationship between the drive unit and the plunger based on a change in the rotation speed of the motor, and controls the lifting operation of the drive unit. Electrophoresis device. 5. An electrophoresis apparatus having a capillary and a detector for optically detecting a sample component introduced into the capillary and electrophoretically separated, the syringe holding a gel to be injected into the capillary. And a drive unit that injects the gel held in the syringe into the capillary by pushing the plunger, and a control unit that controls the operation of the drive unit, and moves the drive unit in the direction to push the plunger. The position of the plunger is detected, and the remaining amount of gel in the syringe is detected. 6. The driving unit according to claim 5,
Electrophoresis including at least a motor that generates power, an actuator that converts a rotational torque of the motor into a propulsive force, a drive unit that applies a force in contact with the plunger, and a linear encoder that detects a movement amount of the drive unit apparatus. 7. The driving unit according to claim 6, wherein the moving speed of the driving unit is obtained from the moving amount of the driving unit read by the encoder, and when the obtained moving speed is smaller than a predetermined threshold value, the driving unit. An electrophoretic device that determines that the contact with the plunger. 8. The electrophoretic device according to claim 6, wherein the control unit determines the positional relationship between the drive unit and the plunger based on a change in the rotation speed of the motor, and controls the moving operation of the drive unit. .