JPH05296965A - Biosensor - Google Patents

Abstract

(57) [Summary] [Purpose] After attaching the immobilized microbial membrane to the biosensor, reduce the dead time until the adhesion between the oxygen permeable membrane and the immobilized microbial membrane becomes stable. [Structure] An electrode body part in which a biosensor detection part is screwed into the center part of the flow cell up to the vicinity of the sample liquid flowing part via an O-ring and fixed to the flow cell, an electrode rod passing through the center of this electrode body part, and the tip of this electrode rod The oxygen permeable film and the immobilization film are sandwiched between the two, and they are in close contact with each other, and a net for allowing the sample liquid to circulate, and an O-ring for closely adhering and fixing the oxygen permeable film to the bottom surface of the electrode body are arranged to fix. The adhesion between the immobilized microbial membrane and the oxygen permeable membrane becomes extremely high, and the increase in the sensor output due to the swelling of the microbial membrane is suppressed. The measurement is stable, and the measurement of the sample liquid can be started with very little waste of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detection part of a biosensor for analyzing components of a sample liquid by means of an immobilization membrane in which an enzyme, a microorganism or the like is used as a molecular identification element (receptor) and immobilized on a porous membrane.

[0002]

2. Description of the Related Art This biosensor is a molecular identification element for recognizing a substance to be measured in a sample liquid, and an immobilization membrane immobilized on a porous membrane by utilizing a biofunctional substance such as an enzyme or a microorganism. In combination with an electrochemical detector using electrodes, the component analysis of the sample liquid is performed. In principle, the sample solution is brought into contact with the immobilization membrane, the change caused by the biochemical reaction caused by this is detected as the output current of the electrode, and the value obtained by performing signal processing on this measured value in the calculation / control unit It has a high selectivity in measurement because it can select various substances to be measured by changing microorganisms and enzymes. Therefore, it is used in the medical field such as blood tests and in the fermentation and food industry such as food quality control. It is widely used in environmental measurement fields such as measurement and wastewater treatment.

The structure of the detecting portion of such a biosensor is shown in the schematic sectional view of FIG. In FIG. 3, the detection part of the biosensor is mainly the immobilized microbial membrane 1, the oxygen permeable membrane 2,
It is composed of a diaphragm type dissolved oxygen electrode 3 and a flow cell 4. The dissolved oxygen electrode 3 is a tubular electrode body 3a.
A tubular electrode upper body 3b and an electrode lower body 3c which are respectively fixed by screw portions formed above and below, an electrode rod 3d having a lower end protruding from the bottom of the electrode body portion 3a at the center of the electrode body portion 3a, and an electrode rod 3d. A flange part 3e attached to the upper end of the flange part of which protrudes from the upper electrode body 3b to the outside, and a flange part 3e.
It is composed of the signal line 3f drawn from the electrode lower body 3c
An O-ring 6 is used to fix between the flow cell 4 and the flow cell 4. The oxygen permeable membrane 2 is fixed to the inside of the lower electrode body 3c below the electrode body 3a through the spacer 5 and the O-ring 6a so as to come into contact with the immobilized microbial membrane 1, and the immobilized microbial membrane 1 is at the central portion. It is fixed to the inner surface of the bottom of the electrode body portion 3a having the liquid passage.

[0004]

The detection part of the biosensor having the above structure has the following problems. That is, in the structure of FIG. 3, the spacer 5 has the electrode rod 3d longer than the electrode body 3a, and the spacer 5 is used for crimping the O-ring 6a that prevents the electrolyte from leaking through the screw portion. Between the immobilized microbial membrane 1 and the oxygen permeable membrane 2 and between the oxygen permeable membrane 2 and the electrode body portion 3a (arrow portion in FIG. 2)
Since there is a gap in the gap, when the measurement is started, the immobilized microbial membrane 1 swells as shown in FIG. 3 due to the growth of microorganisms, and as these gaps come in close contact, the tip of the dissolved oxygen electrode 3 and the immobilized microbial membrane. Since the distance from 1 gradually approaches, the output of the sensor also gradually increases. Therefore, immediately after attaching the immobilized microbial membrane 1, the sample solution cannot be measured until the output of the sensor becomes stable. That is, the problem is that measurement time is wasted until the adhesion between the oxygen permeable membrane 2 and the electrode rod 3d becomes stable.

The present invention has been made in view of the above points, and an object thereof is to detect a sample solution that can be started with very little waste of time after attaching an immobilized microbial membrane. The present invention is to provide a biosensor having a part.

[0006]

In order to solve the above-mentioned problems, the biosensor of the present invention has, as its detection part, a flow cell screwed into the central part of the flow cell up to the vicinity of the sample liquid flow part via an O-ring. A fixed electrode body part, an electrode rod screwed through the center of the electrode body part and having a tip surface flush with the bottom surface of the electrode body part, and the oxygen permeable membrane and the immobilization membrane are sandwiched between the electrode rod tips and these It has a structure in which a mesh-like body which is brought into close contact with a part of which is exposed in the flow cell and through which the sample liquid circulates, and an O-ring which adheres and fixes the oxygen permeable film to the bottom surface of the electrode body portion are arranged.

[0007]

In the biosensor of the present invention, since the detecting portion is constructed as described above, the adhesion between the immobilized microbial membrane and the oxygen permeable membrane is extremely high, and the sensor output is accompanied by the swelling of the microbial membrane. Is suppressed, and the sensor output stabilizes in a short time after attaching the immobilized microbial membrane.
Subsequently, the waste of time is very small, and the measurement of the sample liquid can be performed.

[0008]

EXAMPLES The present invention will be described below based on examples. Figure 1
[FIG. 4] is a schematic cross-sectional view showing a detection portion of the biosensor of the present invention, and the same reference numerals are used for portions common to FIG. Figure 1
3 is different from that in FIG. 3 in that the lower electrode body 3c is also used as the flow cell 4, and the oxygen permeable membrane 2 is fixed to the electrode body portion 3a of the dissolved oxygen electrode 3 by the O-ring 7, and the lower portion thereof The fixed microbial membrane 1 is brought into contact with the fixed microbial membrane 1 so that the fixed microbial membrane 1 does not bend up and down, that is, the fixed microbial membrane 1 does not swell, and a mesh 8 is laid under the fixed microbial membrane 1 to form the electrode body 3a and the flow cell. By fixing 4 with the screw part,
The upper and lower gaps of the immobilized microbial membrane 1 are eliminated, and the electrode body 3
a is attached to the flow cell 4 with the O-ring 7a, and the electrode rod 3
Reference numeral d means that the electrode body portion 3a is fixed with a screw portion.

Since the spacer 5 shown in FIG. 3 is not used in this structure, the electrode body 3a is adhered to the flow cell 4 by the O-ring 7a, and the mesh 8 has the immobilized microbial membrane 1 on the flow cell 4 side. Since it is provided in order to prevent it from being sucked in or protruding downward due to swelling, it may have any mesh-like shape that allows the sample liquid to pass through and has the required strength. It is suitable to use, for example, stainless steel). The reason why the electrode rod 3d is fixed to the electrode body 3a with a screw is to simplify the structure.

As described above, in the detection part of the biosensor of the present invention, the conventionally used spacer is not required, and the immobilized microbial membrane 1 does not have a gap between the immobilized microbial membrane 1 and the oxygen permeable membrane 2. Is restrained on the entire surface, prevents the immobilized microbial membrane 1 from being bent by the metal net 8, and the flow cell 4 also serves as the lower electrode body 3c. .

FIG. 2 is a diagram of the measurement results showing the initial fluctuation of the output when the immobilized microbial membrane is exchanged in the biosensor of the present invention equipped with this detection unit. For comparison, the measurement of the conventional biosensor was carried out. The results are also shown. The vertical axis of FIG. 2 is
The relative output when the sensor output in the first measurement is set to 1, the abscissa represents the elapsed time, the curve plotted with ◯ represents the present invention, and the curve plotted with Δ represents the conventional case. According to the result of FIG. 2, in the detection part of the conventional biosensor, after attaching the immobilized microbial membrane, it took about 1 day until the sensor output appeared, and then it took about 1 day until the output became stable. Whereas a total of 2 days was required, when the detection part of the biosensor of the present invention was used, the sensor output became stable in about 3 hours after mounting the immobilized microbial membrane, and after mounting the microbial membrane, It can be seen that the sample liquid can be measured in a short time.

[0012]

EFFECTS OF THE INVENTION Since a biosensor has a life of an immobilized microbial membrane, it is necessary to periodically replace this membrane. Conventionally, after the immobilized microbial membrane is replaced, until the sensor output becomes stable, Although it was impossible to measure the sample solution, it is natural that the shorter the time until the sensor output stabilizes, the more practical it is. On the other hand, the biosensor of the present invention,
As described in the examples, the structure of the detection unit was improved, the gap between the immobilized microbial membrane, the oxygen permeable membrane and the dissolved oxygen electrode was reduced, and the adhesion between them was improved. The sensor output became stable in about 3 hours, and it became possible to measure the sample liquid immediately after the sensor output became stable, the dead time in measurement was reduced, and a highly practical biosensor could be obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the structure of a detection unit of a biosensor of the present invention.

FIG. 2 is a diagram showing the initial fluctuation of the sensor output when replacing the microbial membrane.

FIG. 3 is a schematic cross-sectional view showing a structure of a detection unit of a conventional biosensor.

[Explanation of symbols]

1 Immobilized Microbial Membrane 2 Oxygen Permeation Membrane 3 Dissolved Oxygen Electrode 3a Electrode Body 3b Electrode Upper Body 3c Electrode Lower Body 3d Electrode Rod 3e Collar 3f Signal Line 4 Flow Cell 5 Spacer 6 O-ring 6a O-ring 7 O-ring 7a O-ring 8 reticulate body

Claims (3)

[Claims] 1. An immobilization membrane in which a biofunctional substance is immobilized on a porous membrane, and a detection section in which a dissolved oxygen electrode and a flow cell are combined, and a sample solution flowing through the flow cell is brought into contact with the immobilization membrane. A biosensor for analyzing components of a sample solution by detecting a biochemical reaction as an output current of a dissolved oxygen electrode of a detection section, which is screwed into a central part of a flow cell to a vicinity of a sample solution channel through an O-ring. An electrode body fixed to the flow cell, an electrode rod screwed through the center of the electrode body and having a tip surface flush with the bottom surface of the electrode body, and an oxygen permeable membrane and an immobilization membrane sandwiched between the electrode rod tips. It is characterized in that it has a detection part in which a reticulate body, which is brought into close contact with each other and a part of which is exposed in the flow cell to allow the sample liquid to flow therethrough, and an O-ring which adheres and fixes the oxygen permeable film to the bottom surface of the electrode body part are arranged Biosensor that. 2. The biosensor according to claim 1, wherein the biofunctional substance is a microorganism. 3. The biosensor according to claim 1 or 2, wherein a metal net is used as the mesh body.