JPS59147249A - Measuring instrument using bio-sensor - Google Patents

Abstract

PURPOSE:To make it possible to easily measure even a small amount of a sample, by providing a bio-sensor to a liquid inhalator. CONSTITUTION:A liquid inhalator is constituted of a cylinder 8, a piston 9 and a needle 10 while an enzyme electrod 11 formed by allowing an electrode plate 11b to immobilize an enzyme film 11a and an opposed electrode 12 are fixed to the inner wall side of the leading end of the cylinder 8 in the side of the needle 10. A potentiostat 6 is connected to the enzyme electrode 11 and the opposed electrode 12 and both electrodes 11, 12 constitute an enzyme sensor. In measuring the concn. of a substrate solution by usng this measuring instrument, the leading end part of the needle 10 is at first immersed in the substrate solution and the piston 9 is withdrawn to such the substrate solution into the cylinder 8. In the next step, voltage is applied between the enzyme electrode 11 and the opposed electrode 12 by the potentiostat 6 and the current value flowing between both electrodes. Thus obtained current value corresponds to the concn. of the basic solution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a measuring device using a biosensor used for measuring the concentration of a substrate solution.

[Background technology]

Measuring instruments using biosensors are excellent in various respects such as substrate specificity, reaction specificity, speed of response, ease of operation, and high sensitivity, and demand has been increasing in recent years.

A measuring device using a conventional biosensor generally has a structure as shown in FIG. This measuring device uses an enzyme sensor, and as shown in the figure, a container is placed on a magnetic stirrer L, and inside the container 2 there is a platinum plate 3b on which an enzyme membrane 3a is fixed. An enzyme electrode (working electrode) 3°, a counter electrode 4, and a magnetic stirrup chip 5 are arranged. The enzyme electrode 3 and the counter electrode 4 constitute an enzyme sensor, and a potentiostat (with an ammeter) 6 is connected to the enzyme electrode 3 and the counter electrode 4.

For example, when measuring the concentration of a substrate solution using this measuring device, proceed as follows. First, enough substrate bath solution 7 to immerse the enzyme electrode 3 and counter electrode 4 is put into the container 2, and the step 5 is rotated by the magnetic stirrer 1 so that the concentration of the entire substrate solution 7 is uniform. Stir 7.

Next, a potential difference is created between the enzyme electrode 3 and the counter electrode 4 using the potentiostat 6, and the value of the current flowing between the electrodes 3 and 4 is measured. This current value corresponds to the concentration of the substrate solution.

However, measuring instruments using such conventional biosensors are based on the premise of measuring large amounts of samples, so the measuring instruments themselves have to be large and difficult to measure small amounts of samples. There was a problem that it was difficult to handle and unsuitable.

However, there was still the problem that a stirring operation was essential during measurement.

[Purpose of the invention]

This invention was made to solve these problems, and it is a biosensor that is small, can easily measure even small amounts of samples, and does not require stirring of the sample. The purpose is to provide the measuring instruments used in this study.

[Disclosure of the invention]

That is, the present invention provides a measuring device using a biosensor, characterized in that a liquid inhaler is provided with a biosensor, and the sample is brought into contact with the biosensor by inhaling the sample liquid. This is the summary. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings.

FIGS. 2 to 4 each show an example of a measuring device using a biosensor according to the present invention. All of these measuring devices have a similar structure to a syringe. The measuring device shown in FIG. 2 consists of a cylinder 8. made of non-conductive material. It is equipped with a piston 9 and a needle 1O, the piston 9 is inserted into the cylinder 8i/il, and the needle 10 is fixed to the tip of the cylinder 8. Cylinder 8. Piston 9 and needle IO constitute a liquid inhaler. Needle 10 of cylinder 8
An enzyme electrode 11 and a counter electrode 12 each having an enzyme membrane 11a fixed to an electrode plate 11b are fixed to the inner wall surface of the side tip. A potentiostat 6 is connected to the enzyme electrode 11 and the counter electrode 12, and both electrodes 11 and 12 constitute an enzyme sensor. The measuring instruments shown in FIGS. 3 and 4 also each have a cylinder 8 made of non-conductive material.
．． It comprises a piston 9 and a needle 13a or 18, which constitute a liquid inhaler. In the measuring device shown in FIG. 3, an enzyme electrode 13 is constructed by fixing an enzyme membrane 13b to the inner wall surface of a needle 13a made of a conductive material. The enzyme electrode 13 is thus fixed to the tip of the cylinder 8, and the counter electrode 14 is fixed to the inner wall surface of the tip of the cylinder 8 on the enzyme electrode 13 side. In the measuring instrument shown in FIG.
6 are integrated via a connecting portion 17 made of an insulating material. The enzyme membrane 15b is fixed to the inner wall surface of the base portion 15a to constitute the enzyme electrode 15, and the tip portion 16 serves as a counter electrode. In both of the double-sided detectors, an enzyme electrode and a counter electrode constitute an enzyme sensor, and a potentiostat (with an ammeter, indicated by 6 in Figure 1) is connected to both electrodes.

When measuring the concentration of a substrate solution (sample) using these measuring devices, proceed as follows. First, the tip of the needle is dipped into the substrate solution, and the piston is pulled to draw the substrate solution (sample) into the cylinder. Next, like conventional measuring instruments,
A voltage is applied between the enzyme electrode and the counter electrode using a potentiostat, and the value of the current flowing between the two electrodes is measured. The obtained current value corresponds to the concentration of the substrate solution.

In these measuring instruments according to the present invention, when the piston is pulled up, the substrate solution flows into the cylinder in a turbulent state, so that the concentration of the entire substrate solution becomes uniform without stirring. Therefore, since a stirring device is not required, the entire measuring device can be made compact, and only a small amount of substrate solution is required as it only needs to fill the space between the enzyme electrode and the counter electrode.

Incidentally, in each of the above embodiments, a liquid inhaler having a structure similar to a syringe is provided, but the liquid inhaler does not necessarily have to have such a structure. In short, any liquid that can do seven things when inhaled is sufficient.

Furthermore, in each of the above embodiments, the liquid inhaler is equipped with an enzyme sensor, but other biosensors (sensors using physiologically active substances) such as microbial sensors and organelle sensors are also installed. The type is not particularly limited. Furthermore, the electrochemical measurement method (device) is not limited to those shown in the examples, and is not particularly limited.

[Effect of the Invention J] Since the measuring device using the biosensor according to the present invention has the biosensor installed in the liquid inhaler, it does not require stirring during measurement and can easily measure even small and small samples. It has become possible.

Next, more specific examples and comparative examples will be described.

[Example IJ Example 1 A measuring device as shown in FIG. 2 was made. However, a platinum plate on which a glucose oxidase membrane was fixed was used as the enzyme electrode, and a silver plate was used as the counter electrode.

[Example 2] As Example 2, a measuring device as shown in FIG. 3 was made. However, using a platinum needle with a glucose oxidase membrane fixed to the inner wall as the enzyme electrode,
A silver plate was used as a counter electrode.

[Example 3] As Example 3, a measuring device as shown in FIG. 4 was made. However, a platinum tube (base of the needle) with a glucose oxidase membrane fixed thereon was used as the enzyme electrode, and a platinum tube (tip of the needle) was used as the counter electrode.

[Comparative example]

As a comparative example, a measuring device as shown in FIG. 1 was made. However, the enzyme electrode used was a 5 x 5 platinum plate on which a glucose oxidase membrane was immobilized, and the counter electrode was a silver plate of the same size as the platinum plate. Further, the interval between both electrodes was set to 5 mm.

Using the measuring instruments of Examples 1 to 3 and Comparative Example, the output currents of glucose solutions at three different concentrations were measured, and a calibration curve was created. The prepared calibration curve is shown in FIG.

From FIG. 5, it can be seen that the calibration curves obtained by the measuring instruments of Examples 1 to 3 are straight lines similar to the calibration curves obtained by the measuring instrument of the comparative example.

Therefore, it can be said that the substrate concentration can be accurately measured by IE using the measuring instruments of Examples 1 to 3.

[Brief explanation of drawings]

Fig. 1 is a structural explanatory diagram of a conventional measuring device using a biosensor, Figs. 2 to 4 are structural explanatory diagrams of a measuring device using a biosensor according to the present invention, and Fig. 5 is a diagram showing glucose concentration and output. This is a graph showing the relationship between currents.

Claims (2)

[Claims] (1) A measuring instrument using a biosensor, characterized in that the liquid inhaler is provided with a biosensor, and the sample is brought into contact with the biosensor by inhaling the sample liquid. (2) A measuring device using a biosensor according to claim 1, wherein the liquid inhaler includes a cylinder, a piston, and a needle.