JPH0426890B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a stirring device for a trace amount of solution.

(Conventional technology) For half a year, micro ion sensors and semiconductor biosensors using semiconductor manufacturing technology have been developed (ed. Shuichi Suzuki, "Biosensors", Kodansha Scientifique, p. 28, 1984).
The size of a semiconductor sensor is, for example, 0.6mm x 0.3mm.
×4 mm ('84 Joint Autumn Electrochemistry Conference, 3rd Chemical Sensor Research Presentation Abstracts P.3)
Since the sensitive part of the sensor is located within 1 mm of its tip, measurement is possible even if the total amount of solution is 30 microliters or less, for example.

However, when measuring chemical substances in a solution using these sensors, constant stirring often yields results with better reproducibility. Furthermore, when a sample is added to a fixed amount of buffer solution for measurement, stirring is essential. Conventionally, rotary blades or magnetic stirrers have been used for this stirring.

(Problem to be solved by the invention) However, most conventional stirring methods target solutions of several milliliters or more;
It was unsuitable for stirring minute amounts of solutions, such as microliters or less. Furthermore, most of the conventional stirring devices use the rotation of a motor as a power source, making the devices quite large.

An object of the present invention is to provide a small-sized device that efficiently stirs minute amounts of liquid droplets.

(Means for Solving the Problems) The present invention is a trace solution stirring device characterized by comprising a vibrator inserted into a sample solution and a piezoelectric actuator that vibrates the vibrator.

(Operation) A piezoelectric actuator is an element that changes shape depending on applied voltage. By bringing this into contact with a vibrator and applying an arbitrary pulse, arbitrary vibrations can be applied to the vibrator. If the tip of the vibrator is inserted into the sample solution, the solution can be efficiently stirred by this vibration. Note that stirring can be performed when the solution is placed in a microcontainer, in a flow cell opened in a closed channel, or as a droplet placed on a hydrophobic substrate. can.

(Embodiment) FIGS. 1a and 1b are diagrams showing an embodiment of the present invention, with a showing a front view and b showing a top view. A glucose sensor 1 in which a glucose oxidase immobilized film is formed on the sensitive part of a field effect ion sensor on a sample droplet 3 dropped on a fluororesin substrate, and a vibrator 2
inserted. The other end of the vibrator is fixed with a support rod 5,
Near this area is a laminated piezoelectric actuator (NEC Corporation).
AE0505D08) 4 was installed so that the displacement of this piezoelectric actuator was directly transmitted to the vibrator.
In the stirring position of the present invention, the supporting rod 5 is not necessarily required. It is also possible to have other displacement magnification mechanisms. Further, the present invention can be installed in a small housing so that it can be easily held in the hand and stirred freely.

In order to measure the glucose concentration in a trace sample, first, a 20mM HEPES-NaOH buffer solution (PH
7.5I = 0.5) was dropped onto the fluororesin substrate, and the sensor chip and vibrator were inserted. Electric pulse to piezoelectric actuator (pulse height 15V, pulse width 1m)
sec, period 140 Hz) was applied for stirring. 6 μl of a sample solution containing 100 mg/dl of glucose was added to this droplet. FIG. 2 shows an example of the change in output over time. FIG. 3 shows an example of the change in output over time when stirring is not applied.

When the stirring device of the present invention was used, as shown in FIG. 2, the output increased immediately after sample addition, reached the saturation value in about 30 seconds, and remained at the same value stably thereafter. When stirring is not applied, the output rises slowly as shown in FIG. 3, and it takes more than 3 minutes to reach the saturation value. The output is unstable and constantly fluctuates, and the saturation value itself is lower than when stirring.

(Effects of the Invention) As described above, by using the stirring device of the present invention, it is possible to measure the concentration of a chemical substance in a minute sample with high precision using a minute sensor. Furthermore, since the stirring device can be miniaturized, by incorporating it into the measuring device, the measuring device itself can be easily miniaturized. Furthermore, the device can be provided at a lower cost than a stirring device using a motor or the like.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention,
FIG. 2 is a diagram showing the response of a glucose sensor when using the device shown in FIG. 1. FIG. 3 is a diagram showing the response of a glucose sensor without using the device of the present invention. In the figure, 1...sensor chip, 2...vibrator, 3...sample droplet, 4...piezoelectric actuator, and 5...support rod are shown, respectively.

Claims (1)

[Claims] 1. A trace solution stirring device comprising a vibrator inserted into a sample solution and a piezoelectric actuator that vibrates the vibrator.