KR102352618B1 - Test strip for immunoassay diagnosis using electric capacitance sensor - Google Patents

Abstract

The present invention relates to an immunoassay test strip using a capacitive sensor, wherein the immunoassay diagnosis is performed in a manner of detecting a change in capacitance that occurs as a target substance is captured in a reaction region, thereby performing an immunoassay diagnosis. There is no need to use a separate light source equipment for the detection of Accordingly, there is provided an immunoassay test strip using a capacitive sensor that can further improve detection accuracy.

Description

TEST STRIP FOR IMMUNOASSAY DIAGNOSIS USING ELECTRIC CAPACITANCE SENSOR

The present invention relates to an immunoassay test strip using a capacitive sensor. More specifically, the immunoassay diagnosis is performed in a manner that detects a change in capacitance that occurs as a target material is captured in the reaction area, thereby eliminating the need to use a separate light source device to detect the material captured in the reaction area. Accordingly, the overall size of the immunoassay diagnostic device can be miniaturized as well as the structure thereof can be simplified, and a capacitive sensor capable of further improving detection accuracy by preventing a detection error caused by an external environment during light detection It relates to an immunoassay test strip using

The test method used for disease diagnosis is mainly based on color development by enzymatic reaction, fluorescence, etc., but recently, a method using an immunoassay using an immune reaction between an antigen and an antibody is also used. This immunoassay method mainly uses a label-type biosensor that can label an antibody with a radioactive isotope or a fluorescent substance to determine the presence or absence of an antigen, and quantify it by the intensity of radiation or fluorescence.

Conventional immunoassay methods include a method of measuring a signal obtained by labeling an antigen or antibody with a radioactive material, a luminescent material or a fluorescent material, ELISA (Enzyme Linked Immunosorbent Assay: ELISA), Western blotting Optical measurement methods such as Western blotting have been used the most. These methods mainly require complicated procedures that can be performed by skilled researchers mainly in laboratories, and have disadvantages in that the apparatus for analysis is an expensive and large-scale apparatus, and the analysis time is long.

Antibodies, which are the target substances of the immune sensor, exist at very low concentrations in biological samples such as whole blood, serum, and urine. In terms of the detection limit of In addition, since the structures of antibodies, protein antigens, and the like, are easily changed by changes in the external environment, the recognition site of the antigen or antibody is easily altered to lose its intrinsic biorecognition function. Under the circumstances of the immune sensor that needs to be analyzed in a solid form, a sensor surface suitable for a biomaterial that can maintain the activity of these biomaterials, an immobilization technology for a biomaterial that can increase the detection limit, and a quantified signal for biorecognition It is necessary to secure a measuring method that converts.

A rapid diagnostic test kit for immunoassay is a test tool for a point-of-care in which a diagnostic test can be performed using a biological sample such as blood, urine, saliva, and the like. Examples of such rapid diagnostic test kits include a pregnancy diagnostic kit, an AIDS diagnostic kit, and the like.

Such a diagnostic device must establish a method capable of detecting a predetermined biological material (protein, DNA, antigen, etc.) for diagnosis. As a conventional biomaterial detection method, there are a fluorescent labeling method using an organic dye or the like, and a reflected light labeling method using a reflected light material or the like.

The immunoassay diagnostic apparatus operates on the same operating principle as either a fluorescent method or a reflected light method, and uses a test strip capable of adsorbing and supplying a biological sample through capillary action. Since the biological sample flows laterally in the test strip in the longitudinal direction due to capillary action, this method is also referred to as a lateral flow immunoassay.

1 is a diagram conceptually illustrating the structure of a general immunoassay test strip, and FIG. 2 is a view for explaining the immunoassay diagnostic principle of a general immunoassay test strip.

In general, the test strip 10 includes a sample pad 11 , a probe pad 12 , a membrane 13 , and an adsorption pad 14 sequentially disposed along the longitudinal direction. A biological sample BT is supplied to the sample pad 11 , and the supplied biological sample BT flows from the sample pad 11 to the probe pad 12 , the membrane 13 , and the adsorption pad 14 by capillary action. flow sequentially. A detection reagent P is applied to the probe pad 12 so as to bind to a target analyte T (antigen, etc.) in the biological sample BT, and the detection reagent P is a target analyte ( The probe material (R) is formed in a fixed form by binding to the biomaterial (S1) capable of binding to T). Accordingly, while the biological sample BT flows, the target analyte T and the detection reactant P are combined in the probe pad 12 to form the detection biological binding body M. A reaction region 15 to which a capture material S2 is applied is formed in the membrane 13 to capture the bio-binding compound M for detection, and in the reaction region 15, the detection bio-binding compound M and the capture material S2 are formed. ) are combined to form a biocomplex (V) for detection. The reaction region 15 is formed in the form of a line transverse to the membrane 13 in the width direction, and the membrane 13 has a separate control line 16 for determining the validity of the test in addition to the reaction region 15 . can be formed. The adsorption pad 14 is made of a porous material to enable adsorption movement of the biological sample BT.

After the flow process of the biological sample BT in the test strip 10 is completed, when the test light is irradiated to the reaction area 15 of the test strip 10 using the optical device 20, the reaction area 15 Fluorescence is generated in the biocomposite (V) for detection of , or reflected light is generated by reflection of inspection light, and a diagnosis for a specific disease factor is performed by detecting such fluorescence or reflected light. At this time, fluorescence or reflected light is generated by the probe material (R) included in the biocomposite (V) for detection, and fluorescence or reflected light is generated depending on the type of the probe material (R).

According to this structure, the fluorescence immunoassay diagnostic device uses ultraviolet light as the type of test light to generate fluorescence in the detection biocomplex to detect fluorescence, and the reflected light type immunoassay diagnostic device uses white light as the test light type. , by reflecting the inspection light from the detection biocomplex to detect the reflected light. It is possible to diagnose whether there is a specific disease factor by analyzing the detection intensity of the detected fluorescence or reflected light.

Accordingly, the immunoassay diagnostic apparatus needs to irradiate a specific test light to the reaction region 15 regardless of the fluorescent method or the reflected light method. , an optical system having a complex structure such as a plurality of lens modules for guiding the optical path was absolutely necessary, and accordingly, the size of the equipment is increased and the structure is complicated, and there are problems such as there is a limit to the miniaturization of the equipment, and also In the detection process, there is a problem such as a decrease in detection accuracy due to the influence of an external environment or the like.

Domestic Patent Publication No. 10-2010-0104394

The present invention was invented to solve the problems of the prior art, and an object of the present invention is to perform immunoassay diagnosis in a manner that detects a change in capacitance that occurs as a target material is captured in a reaction region, thereby There is no need to use a separate light source equipment for detection of captured substances in To provide an immunoassay test strip using a capacitive sensor capable of further improving detection accuracy by preventing detection errors.

Another object of the present invention is to apply a probe material that functions as an indicator as a material with high capacitance, so that even if the number of target analytes exists in a small amount in a biological sample, it can be accurately detected, and the static electricity according to the number of target analytes is An object of the present invention is to provide an immunoassay test strip using a capacitive sensor that can perform an analysis task for a specific disease factor in more various ways because the change value of the dose is clear.

The present invention provides a strip pad with a biological sample supplied to one end and adsorbed to flow toward the other end, and a reaction region is formed on one side to capture a target analyte in the biological sample; and a capacitive sensor coupled to one surface of the strip pad to detect a change in capacitance generated according to the capture of the target analyte in the reaction region, wherein the change in capacitance detected through the capacitive sensor To provide a test strip for immunoassay using a capacitive sensor, characterized in that the immunoassay diagnosis is performed through the

In this case, the strip pad may include: a sample pad to which a biological sample is supplied; and a membrane connected to the sample pad so that the biological sample is adsorbed and flows from the sample pad by capillary action, the membrane is formed elongated in one direction, and the reaction region is formed on one side.

In addition, the strip pad further includes a probe pad disposed between the sample pad and the membrane, and the biological sample supplied to the sample pad sequentially flows from the sample pad through the probe pad to the membrane, and A detection reagent may be applied to the probe pad to bind to a target analyte in the biological sample, and the target analyte in a state in which the detection reagent is bound may be captured in the reaction region of the membrane.

In addition, a capture material is applied to the reaction region of the membrane to capture the target analyte to which the detection reagent is bound, and the detection reagent applied to the probe pad has a material having a relatively larger capacitance than the capture material. can be applied.

In addition, the detection reactant is formed in a structure in which a separate probe material is fixedly bonded to a biological material capable of binding to the target analyte, and the probe material is applied as a material having a relatively larger capacitance than the capture material. can

In addition, the probe material of the detection reactant may be applied as a material having a relatively larger capacitance than the target analyte and the biological sample.

In addition, the capacitive sensor may be arranged to contact at least a partial region of the membrane including the reaction region.

According to the present invention, it is necessary to use a separate light source device to detect the substance captured in the reaction region by performing immunoassay diagnosis in a manner that detects a change in capacitance that occurs as a target substance is captured in the reaction region. Accordingly, the overall size of the immunoassay diagnostic device can be miniaturized, and the structure can also be simplified, and the detection accuracy can be further improved by preventing a detection error caused by an external environment during light detection. have.

In addition, by applying the probe material that functions as an indicator as a material with high capacitance, even if the number of target analytes exists in a small amount in the biological sample, it can be accurately detected, and the change in capacitance according to the number of target analytes Because this is clear, there is an effect that analysis work for specific disease factors can be performed in more various ways.

1 is a diagram conceptually illustrating the structure of a test strip for general immunoassay;
2 is a view for explaining the immunoassay diagnostic principle of a general immunoassay test strip;
3 is a diagram schematically showing the structure of a test strip for immunoassay using a capacitive sensor according to an embodiment of the present invention;
4 is a diagram schematically showing the structure of a test strip for immunoassay using a capacitive sensor according to another embodiment of the present invention;
5 is a view conceptually illustrating a reaction state appearing in a reaction region of a test strip according to an embodiment of the present invention;
6 is a diagram exemplarily illustrating a change in capacitance of a reaction region of a test strip according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

3 is a diagram schematically showing the structure of a test strip for immunoassay using a capacitive sensor according to an embodiment of the present invention, and FIG. 4 is a view showing immunity using a capacitive sensor according to another embodiment of the present invention. It is a diagram schematically showing the structure of a test strip for analysis, FIG. 5 is a diagram conceptually illustrating a reaction state appearing in a reaction region of a test strip according to an embodiment of the present invention, and FIG. 6 is an embodiment of the present invention It is a diagram exemplarily illustrating a change in capacitance of a reaction region of a test strip according to an example.

The test strip for immunoassay using a capacitive sensor according to an embodiment of the present invention enables immunoassay diagnostic work using a capacitance change value rather than a photodetection method using general optical equipment, and the strip pad ( 100 ) and a capacitive sensor 200 .

The strip pad 100 is formed such that the biological sample BT is supplied to one end and adsorbed and flows toward the other end, and a reaction region 110 is provided on one side to capture the target analyte T in the biological sample BT. is formed

The capacitive sensor 200 is coupled to one surface of the strip pad 100 to detect a change in capacitance generated according to the capture of the target analyte T in the reaction region 110 . The capacitive sensor 200 is a sensor that measures the capacitance of an external contact in contact with the sensor contact surface, and is widely used in industry like a capacitive fingerprint recognition sensor, so that the structure of the capacitive sensor 200 is Detailed description will be omitted.

As described above, in the test strip for immunoassay according to the present invention, when the target analyte T, which is a specific disease factor, is present in the biological sample BT on the strip pad 100, the target analyte T is transferred to the reaction region 110 . Since it is captured in , the capacitance detected in the reaction region 110 by the captured material increases, and by detecting this increase in capacitance through the capacitive sensor 200 , a specific disease factor in the biological sample BT can be diagnosed as being present.

According to this structure, there is no need to use a separate light source equipment to detect the substance captured in the reaction region 110, so that the overall size of the immunoassay diagnostic apparatus can be miniaturized and the structure can be simplified, and when light is detected Detection accuracy can be further improved by preventing detection errors caused by external environments.

In more detail, the strip pad 100 is a sample pad 101 to which the biological sample BT is supplied, and the biological sample BT is capillary from the sample pad 101 as shown in FIG. 3A . It may be configured to include a membrane 103 connected to the sample pad 101 and formed to be elongated in one direction so as to adsorb flow by the above-described reaction region 110 on one side. A capture material S2 is applied to the reaction region 110 of the membrane 103 to capture the target analyte T in the biological sample BT. The reaction region 110 is formed in a line shape in a direction crossing the membrane 103 in the width direction, and a plurality of reaction regions 110 may be formed to be spaced apart from each other as needed. In addition, a control line 120 having the same line shape may be formed in the downstream region of the reaction region 110 , and a capture material S2 is applied to the control line 120 to capture the target analyte T, Through this, the validity of the test can be judged. Meanwhile, an adsorption pad 104 made of a porous material is disposed at an end of the membrane 103 opposite to the sample pad 101 to induce an adsorption flow of the biological sample BT.

The capacitive sensor 200 is formed in a flat plate shape and is disposed to contact a partial area of the upper surface of the membrane 103 including the reaction area 110 to detect the capacitance in the contact area. Since both the biological sample BT and the capture material S2 are biological materials, when they come into contact with the capacitive sensor 200 , their capacitance is detected at a significant level, and the capture material S2 and the target are located in the reaction region 110 . When the analyte T or the like is concentrated, the capacitance in the reaction region 110 is further increased.

According to this structure, when the biological sample BT is supplied to the sample pad 101 , the supplied biological sample BT is sequentially transferred from the sample pad 101 to the membrane 103 and the adsorption pad 104 by capillary action. flow The target analyte T (eg, antigen) in the biological sample BT while the biological sample BT flows through the membrane 103 to the adsorption pad 104 is shown in FIG. 3B . As described above, it is captured by the capture material S2 of the reaction region 110 .

When the target analyte T is captured by the capture material S2 in the reaction region 110 , the target analyte T is additionally present in the reaction region 110 in addition to the capture material S2, so the reaction region ( 110), the concentration of the capture material (S2) and the target analyte (T) increases, and when a plurality of the target analytes (T) are included in the biological sample (BT), more target analytes (T) is concentrated and the density further increases. In this case, the stacking height may be increased by concentration of multiple materials. Accordingly, in the reaction region 110 , the density of the material in contact with the capacitive sensor 200 is high, so that the capacitance detected by the capacitive sensor 200 increases. That is, when the target analyte T is captured, the capacitance detected by the capacitive sensor 200 increases compared to the case where only the initial capture material S2 is present in the reaction region 110 . It is possible to diagnose whether there is a specific disease factor by determining whether the increase in the electrical signal value due to the capacitance is greater than or equal to a reference value.

Meanwhile, in the test strip for immunoassay using a capacitive sensor according to another embodiment of the present invention, the probe pad 102 disposed between the sample pad 101 and the membrane 103 of the strip pad 100 is further added. include The biological sample BT supplied to the sample pad 101 sequentially flows from the sample pad 101 to the membrane 103 through the probe pad 102 .

As shown in (a) of FIG. 4 , the probe pad 102 is coated with a detection reactant P so as to bind to the target analyte T in the biological sample BT. The detection reactant (P) is formed in a structure in which a separate probe material (R) is fixedly coupled to a biological material (S1) capable of binding to the target analyte (T). As described with reference to FIG. 3 , a capture material S2 capable of capturing the target analyte T is applied to the reaction region 110 of the membrane 103 .

More specifically, in the detection reactant (P), a separate probe material (R) is fixedly coupled to a biological material (S1) capable of binding to a target analyte (T), in this case, the biological material (S1) is , For example, nucleic acid including DNA or RNA, amino acid, fat, glycoprotein, antibody, or a combination material thereof may be applied. The capture material S2 may also be applied as the same material as the biological material S1 .

On the other hand, the detection reactant (P) is a gas phase condensation method (gas phase condensation method), high frequency plasma chemical synthesis method (high frequency plasma chemical synthesis method), chemical precipitation method (conventional chemical precipitation), hydrothermal synthesis method (hydrothermal synthesis method), Electric dispersion re-action method, combustion synthesis method, sol-gel synthesis method, thermochemical synthesis method, microfludizer process , microemulson technology, high energy mechanical milling, or a combination thereof.

According to this structure, when the biological sample BT is supplied to the sample pad 101 , the supplied biological sample BT is transferred from the sample pad 101 to the probe pad 102 , the membrane 103 , and the adsorption pad by capillary action. flow sequentially to (104). During the flow of the biological sample BT, as shown in FIG. 4B , in the probe pad 102 , the target analyte T in the biological sample BT is combined with the detection reagent P Thus, the detection bio-conjugate (M) is formed. In the reaction region 110 of the membrane 103, the target analyte T bound to the detection reagent P, that is, the detection bio-binding body M, is captured by the capture material S2, The binder (M) and the capture material (S2) are combined to form a biocomplex (V) for detection.

In a state in which the target analyte T is not present in the biological sample BT or the biological sample BT does not adsorb and flow, the capture material S2 is disposed in the reaction region 110 as shown in (a) of FIG. 5 . ), the capacitance signal detected by the capacitance sensor 200 as shown in FIG. 6A shows a relatively low V1 value.

When the target analyte (T) is present in the biological sample (BT), the target analyte (T) combined with the detection reactant (P), that is, the detection biological binding body (M) is generated, as shown in FIG. 5(b) ), it is captured by the capture material S2 in the reaction region 110 and forms a biocomposite V for detection. As the number of target analytes T increases, more biocomposites V for detection are formed in the reaction region 110 . As described above, the number of biocomposites V for detection in the reaction region 110 increases as a result of electrostatic Since the number of materials in contact with the capacitive sensor 200 is large, the capacitive signal detected by the capacitive sensor 200 increases, indicating a relatively high V2 value. It is possible to diagnose whether there is a specific disease factor by determining whether the amount of increase in the electrical signal value according to the capacitance is greater than or equal to a reference value.

In this case, in an embodiment of the present invention, a material having a relatively larger capacitance than the capture material S2 for the detection reactant P applied to the probe pad 102 may be applied. More specifically, the probe material R of the detection reactant P may be applied as a material having a relatively larger capacitance than the capture material S2. In addition, the probe material R may be applied as a material having a higher capacitance than the target analyte T and the biological sample BT.

To apply the probe material (R) as a material with a relatively large capacitance, establish a database on the capacitance of each material through various experiments measuring the capacitance of a plurality of materials that can be applied as a probe material, and , referring to this, it is possible to select a probe material (R) applicable to diagnosis of a specific disease. Of course, databases on capacitances of the target analyte (T), the biological sample (BT), the biological material (S1), and the capture material (S2) must also be established through various capacitance experiments. Test strips with applicable specifications are produced according to the type of target analyte (T) corresponding to a specific disease factor, and the test strip is applied to perform immunodiagnostic work when diagnosing a specific disease factor. can be configured.

As described above, since the probe material R is applied as a material having a relatively large capacitance, when the detection biocomposite V including the probe material R is formed in the reaction region 110 , the probe material R Accordingly, the capacitance signal detected by the capacitive sensor 200 in the reaction region 110 increases. In this case, the increase in the capacitance signal will be larger according to the number of probe materials R.

Therefore, when the probe material R is applied as a material having a large capacitance, even if the number of target analytes T in the biological sample BT is relatively small compared to FIG. 3 , the probe material R Since the capacitance signal value is relatively significantly increased, the presence or absence of the target analyte T may be more accurately detected.

As described above, in the test strip for immunoassay according to the present invention, the static electricity generated by the capture of the detection reactant (P) (including the probe material (R)) bound to the target analyte (T) in the reaction region 110 . By detecting the change in capacitance using the capacitive sensor 200, it is possible to diagnose specific disease factors in a way that detects an electrical signal rather than a photodetection method using a light source device, unlike the prior art, Accordingly, it is possible not only to miniaturize the entire diagnostic apparatus, but also to enable more accurate diagnosis.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: strip pad
101: sample pad
102: probe pad
103: membrane
104: suction pad
110: reaction zone
120: control line
200: capacitive sensor
BT: biological sample
T: target analyte
P: reactant for detection
R: probe material
S1: biomaterial
M: bioconjugate for detection
V: biocomplex for detection
S2: capture material

Claims (7)

a strip pad having one end supplied with a biological sample and adsorbed and flowing toward the other end, and having a reaction region formed on one side to capture a target analyte in the biological sample; and
A capacitive sensor coupled to one surface of the strip pad so as to be in contact with the reaction area, and detecting the capacitance of a biological material in contact with the sensor contact surface through the reaction area
Including, as the target analyte is captured in the reaction region, the amount of contact of the biomaterial that comes into contact with the capacitive sensor in the reaction region increases, which is caused by an increase in capacitance detection of the capacitive sensor. A test strip for immunoassay using a capacitive sensor, characterized in that it can perform.
The method of claim 1,
The strip pad is
a sample pad to which a biological sample is supplied; and
A membrane in which the biological sample is connected to the sample pad and formed to be elongated in one direction so that the biological sample is adsorbed and flows from the sample pad by capillary action, and the reaction region is formed on one side
A test strip for immunoassay using a capacitive sensor, comprising:
3. The method of claim 2,
The strip pad is
Further comprising a probe pad disposed between the sample pad and the membrane,
The biological sample supplied to the sample pad sequentially flows from the sample pad through the probe pad to the membrane,
A capacitive sensor, characterized in that the probe pad is coated with a detection reagent so as to bind to the target analyte in the biological sample, and the target analyte in a state in which the detection reagent is bound is captured in the reaction region of the membrane. Test strips for immunoassay using.
4. The method of claim 3,
A capture material is applied to the reaction region of the membrane to capture the target analyte to which the detection reactant is bound;
A test strip for immunoassay using a capacitive sensor, characterized in that a material having a relatively larger capacitance than that of the capture material is applied to the detection reactant applied to the probe pad.
5. The method of claim 4,
The detection reactant is formed in a structure in which a separate probe material is fixedly bound to a biological material capable of binding to the target analyte, and the probe material is applied as a material having a relatively larger capacitance than the capture material. A test strip for immunoassay using a capacitive sensor characterized.
6. The method of claim 5,
The test strip for immunoassay using a capacitive sensor, characterized in that the probe material of the detection reactant is applied as a material having a relatively larger capacitance than the target analyte and the biological sample.
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