JPH05232114A - Immunity sensor system and immunity inspecting method using immunity sensor system - Google Patents

Abstract

PURPOSE:To perform measurement, which is simpler and more positive than the conventional methods, by detecting only the change in mass caused by antigen-antibody reaction, and suppressing the fluctuation of phase difference caused by buoyant latex in an immunity sensor system and an immunity inspecting method using this system. CONSTITUTION:A solution flow system, which sends buffer liquid, latex solution wherein antigens are modified and specimen solution into a measuring cell 4, is provided in a constant temperature oven 2 together with the measuring cell. As the inspecting method, at first, the phase difference of an acoustic device when only the buffer liquid is present is measured. Then, the latex, wherein the antigens are modified, and the antigens in the specimen are made to undergo competitive reaction for a specified time. Then, only the buffer liquid is made to remain again, and the phase difference is measured. The amount of the antigens in the specimen is detected based on the change in phase differences of both the latex and the antigens.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an immunosensor system using a Lamb wave mode acoustic device and an immunoassay method using the immunosensor system.

[0002]

2. Description of the Related Art Acoustic devices cause a shift in resonance frequency and phase difference due to changes in temperature, humidity, etc.
It has been widely used as a temperature sensor and a humidity sensor. The acoustic device causes a shift of the resonance frequency and a phase difference even when the mass attached to the surface of the acoustic device changes. Moreover,
It has high mass sensitivity and can detect minute changes in mass during antigen-antibody reaction. Attempts have been made to use the property as an immunosensor. Such an immunosensor has advantages such as high sensitivity and shortened test time, as compared with conventional tests for antigen-antibody reaction. Since the antigen-antibody reaction is carried out in water, measurement in water is required. In that case, there are many cases where the acoustic wave escapes into the water, and the acoustic wave in the mode in which the underwater measurement can be performed is limited. Acoustic waves that can be measured in water include Lamb waves and SH surface waves. In particular, acoustic devices using Lamb wave mode are expected to have good mass sensitivity, and using Lamb wave mode makes it possible to measure mass changes during antigen-antibody reaction (RMWhite and SW
Wenzel, Appl. Phys. Lett. 52, 1653 (1988)).

[0003]

When a latex solution is put into a reaction cell to cause an antigen-antibody reaction, not only the mass but also the temperature and the viscosity of the solution change. Since the acoustic device has relatively high sensitivity not only to changes in mass but also to changes in temperature, humidity, viscosity of liquid, etc., only the changes in mass of latex adsorbed by the antigen-antibody reaction should be detected by the acoustic device. It's difficult. Further, during the immune reaction, the floating latex that has not been adsorbed on the surface of the acoustic device becomes noise during measurement, which causes an error.
An object of the present invention is to solve such conventional problems and to provide an immunosensor system capable of sensing only a mass change due to an antigen-antibody reaction and performing a reliable measurement.

[0004]

A first aspect of the present invention is an immunosensor system using a Lamb wave mode acoustic device for measuring a buffer solution, a latex solution modified with an antigen and a sample solution with an immunosensor attached. An immunosensor system comprising a solution flow system for feeding into a cell, wherein a sensor and a measuring cell, and a solution flow system are installed in a constant temperature bath. Second
Is an immunoassay method using the above immunosensor system, wherein a phase difference between an input side and an output side of an ultrasonic wave propagating between two electrode pairs of an acoustic device whose surface is modified with an antibody is reacted. After only the buffer solution is put into the cell for measurement, the antigen-modified latex and the antigen in the sample are allowed to undergo a competitive reaction for a certain period of time, and only the buffer solution is again measured to measure the above-mentioned phase difference. An immunoassay method characterized by detecting the amount of antigen in a sample from a phase difference change.

[0005]

By using the immunosensor system and the immunoassay method equipped with the above means, the temperature of the sensor part and the amount of buffer solution before and after the reaction can be kept constant regardless of the environment during the immune reaction. As long as they are set, only the mass change due to the immune reaction can be detected.

[0006]

EXAMPLES Next, examples of the present invention will be described. Figure 1
Is an embodiment of the immunosensor system to which the present invention is applied. The immunosensor system comprises an acoustic device 1 whose back surface is modified with an antibody, a thermostatic chamber 2, a gain phase analyzer 3, and a solution flow system. The antibody film modified on the back surface of the acoustic device reacts with the antigen or the latex modified with the antigen. The change in the mass of the surface of the acoustic device when the antigen-antibody reaction occurs causes a shift in the phase difference of the acoustic device. In order to know the adsorption amount of the antigen that has reacted with the antibody film or the latex modified with the antigen, it is necessary to suppress only the change in the mass of the surface of the acoustic device and suppress the change in other physical amounts. The acoustic device and the solution flow system are placed in a thermostatic chamber to suppress temperature changes. Further, in order to keep the pressure load on the acoustic device constant, the position of the solution amount adjusting tube 8 is fixed so that the amount of the solution put in the cell becomes constant. In the immune reaction, the final measurement is performed in the buffer solution alone in order to eliminate the adverse effect of the floating latex that has not been adsorbed on the acoustic device on the phase difference measurement of the acoustic device. The latex solution is discharged through the solution discharge tube 9 and replaced with the buffer solution.

FIG. 2 is an explanatory view showing the appearance of the front surface of the gold film 10 attached to the back surface of the acoustic device during the immunological test. In the immunological test, first, the phase difference of the acoustic device before causing an immune reaction is measured with a gain phase analyzer. The surface of the acoustic device before the immune reaction is shown by (a), and BSA (Bovine Serum Albumi) for preventing the adsorption of the antibody 11 and the latex on the gold film is shown.
n) is modified. The solution of the latex 14 modified with the antigen and the sample solution containing the antigen 13 are injected into the measurement cell and reacted for a certain period of time (FIG. 2 (b)), and then the solution is discharged through the solution discharge tube. After adding the buffer solution and making it the same as the amount before the reaction using the tube for adjusting the solution amount (Fig. 2
(c)), Measure the phase difference of the acoustic device. By preliminarily examining the relationship between the latex adsorption amount and the phase difference change and the relationship between the latex adsorption amount and the antigen amount, the antigen amount of the sample can be obtained from the phase difference change before and after the reaction.

[0008]

As described above, if the present invention is applied, only the mass change due to the antigen-antibody reaction is detected, the fluctuation of the phase difference due to the floating latex is suppressed, and the simpler and more reliable measurement than ever. You will be able to do it.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of an immunosensor system of the present invention.

FIG. 2 is a schematic diagram of an antigen-antibody reaction in one example of the immunoassay method of the present invention.

[Explanation of symbols]

 1 Acoustic device with modified antibody on the back surface 2 Constant temperature bath 3 Gain phase analyzer 4 Measurement cell 5 Buffer solution reservoir 6 Latex solution reservoir with modified antigen 7 Specimen solution reservoir 8 Solution volume adjustment tube 9 Solution discharge tube 10 Gold film 11 antibody 12 BSA 13 antigen 14 latex modified with antigen

Claims (2)

[Claims] 1. An immunosensor system using a Lamb wave mode acoustic device, comprising a solution flow system for feeding a buffer solution, a latex solution modified with an antigen, and a sample solution into a measurement cell equipped with an immunosensor. An immunosensor system characterized in that a sensor, a measuring cell, and a solution flow system are installed in a constant temperature bath. 2. An immunoassay method using the immunosensor system according to claim 1, wherein a position of an output side with respect to an input side of an ultrasonic wave propagating between two electrode pairs of an acoustic device whose surface is modified with an antibody. After measuring the phase difference by putting only the buffer solution into the reaction cell, the antigen-modified latex and the antigen in the sample are allowed to undergo a competitive reaction for a certain period of time, and only the buffer solution is measured again to measure the phase difference, before and after the immune reaction. An immunoassay method characterized by detecting the amount of antigen in a sample from the change in the phase difference between the two.