KR102530748B1 - Apparatus and method for detecting sample using nanowire fet - Google Patents

Abstract

The present invention is provided with a source electrode connector and a drain electrode connector electrically connectable to the source electrode and the drain electrode of the nanowire FET, and also provides a current flowing from the source electrode to the drain electrode of the nanowire FET to an I-V converter, an operational amplifier, and an ADC. As it is configured to measure through, it is possible to detect the sample using the nanowire FET, and it is possible to miniaturize the device because it does not require large-scale microcurrent measurement equipment.

Description

Sample detection device and method using nanowire FET {APPARATUS AND METHOD FOR DETECTING SAMPLE USING NANOWIRE FET}

The present invention relates to a device and method for detecting a sample included in a specimen using a nanowire field effect transistor (FET).

In the FET (hereinafter referred to as 'nanowire FET')-based biosensor technology using nanowires made of Silicon Nanowire, Carbon Nanotube, or Graphene, a nanowire is provided in a channel, and a receptor (sensing material) is attached to the nanowire. After fixing the sample (DNA, RNA, antibody, hormone, cell, etc.) contained in the sample, it is a technique to determine whether the sample exists in the sample by measuring the current generated as it binds to the receptor.

This nanowire FET-based biosensor technology has a significantly higher reaction sensitivity (i.e., the degree of reaction between the sample and the receptor) compared to diagnostic technologies that are currently generally used, making diagnosis with only a very small amount of sample (i.e., the sample contains the sample). whether or not) is possible. In addition, nanowire FET-based biosensor technology can react with a sample even if the sample is an aqueous solution, so there is no need to use expensive fluorescent materials for microcurrent detection, so the test cost is very low and the current The time required for detection is within a few seconds, making it a very suitable technology for use as an on-site diagnostic test method.

Conventionally, it has been successful in detecting prostate-specific antigen, Prostate Specific Antigen (PSA) molecules, up to a very small amount of 0.9 pg/ml using a silicon nanowire FET biosensor, Research results of detecting various types of biomaterials such as IgE protein, streptavidin, DNA, and glucose using a carbon nanotube FET biosensor have also been reported. In Korea, research results have been reported on the development of a high-performance carbon nanotube FET biosensor capable of cancer diagnosis, single molecule detection, and harmful gas detection. In addition, a Korean research team recently succeeded in detecting COVID-19 using graphene, demonstrating the possibility of developing innovative diagnostic technology.

Despite these successful research results, the reason why the diagnostic technology using the nanowire FET has not been commercialized is the difficulty in manufacturing the nanowire FET chip. More specifically, first, it is difficult to disperse the nanowires in a solvent with a uniform density, and secondly, the nanowire FETs constituting the nanowire FET chip appear in the channel connecting the source electrode and the drain electrode so that they have a constant resistance. This is because the technology for arranging routes is still lacking. Because of these circumstances, the diagnosis technology using the nanowire FET chip is still at the research level in universities or research institutes, and accordingly, in most actual fields, expensive large-scale microcurrent measurement equipment called probe stations are used.

It is recognized as self-evident that an era in which health status diagnosis such as genetic diagnosis or disease diagnosis can be performed in real time using a biosensor will come in the near future. In addition, it is expected that the use of biosensors will rapidly expand not only in medical biosensors, which currently account for the vast majority of biosensors, but also in biochemical weapon detection, environmental (water/air/soil) monitoring, and animal and plant quality inspections. . Accordingly, it is predicted that the development of biosensor technology will also develop a high-quality multifunctional biosensor that overcomes the current limitations by utilizing the BT-IT-NT convergence technology.

Nanowire FET-based biosensor technology is the most suitable technology as a point-of-care technology (POCT) in all aspects, such as reaction sensitivity, required sample amount, detection time, and economic feasibility. In light of this aspect, there is an urgent need to develop a miniaturized sample detection device that can be easily utilized in the field using nanowire FETs.

K. Maehashi, K. Matsumoto, Y. Takamura, and E. Tamiya, "Aptamer-Based Label-Free Immunosensors Using Carbon Nanotube Field-Effect Transistors," Electroanalysis., 21 [11] 1285-90 (2009) J.-O Lee, H.-M. So, E. -K. Jeon, H. Chang, K. Won, and Y. H. Kim, "Aptamers as Molecular Recognition Elements for Electrical Nanobiosensors," Anal. Bioanal. Chem., 390 [4] 1023-32 (2008) Rapid Detection of COVID-19 Causative Virus (SARS-CoV-2) in Human Nasopharyngeal Swab Specimens Using Field-Effect Transistor-Based Biosensor, Giwan Seo et al., ACS Nano 2020, 14, 4, 5135-5142

An object of the present invention is to provide a method for detecting a sample included in a specimen by using a nanowire FET.

In addition, an object of the present invention is to provide a method for miniaturizing a device by overcoming a technology limitation in not arranging nanowires in a channel so that nanowire FETs have a constant resistance.

Furthermore, an object of the present invention is to provide a method capable of improving the detection accuracy of a sample included in a specimen.

In order to achieve the above object, a sample detection device using a nanowire FET according to an embodiment of the present invention includes a source electrode and a drain electrode, and a channel connecting the source electrode and the drain electrode includes a nanowire. A sample detection device using at least one nanowire FET provided with a wire and a receptor, comprising: a source electrode connector electrically connected to the source electrode; a drain electrode connector electrically connected to the drain electrode; an I-V converter electrically connected to the drain electrode connector and converting a current flowing from the source electrode to the drain electrode into a voltage when an analyte is applied to the channel; an operational amplifier amplifying the voltage converted by the I-V converter; an ADC (Analog-Digital Converter) for converting the voltage amplified by the operational amplifier into a digital count value; and a micro controller unit (MCU) for detecting a sample included in the specimen through a digital count value converted by the ADC.

A sample detection device using a nanowire FET according to an embodiment of the present invention is electrically connected to the source electrode connector, receives a source voltage application command output from the MCU, and receives the source voltage application command according to the source voltage application command. A digital-analog converter (DAC) for applying a source voltage to the electrode may be further included.

A sample detection device using a nanowire FET according to an embodiment of the present invention includes a power input unit receiving external power; and a battery charged by external power input to the power input unit, wherein the I-V converter, the operational amplifier, the ADC, the MCU, and the DAC are operated by the power charged in the battery. can

The MCU obtains a background signal, which is a digital count value output by the ADC, in a state in which only the nanowire and the receptor are provided in the channel, before a sample is applied to the channel, and the background signal is present within a preset background signal range and if the background signal does not exist within the preset background signal range, a source voltage adjustment command may be output to the DAC so that the background signal exists within the preset background signal range. .

In addition, the MCU obtains a blank signal, which is a digital count value output by the ADC in a state in which a blank reagent is applied to the channel after the background signal is present within the preset background signal range, and the blank signal It is determined whether a value obtained by subtracting the background signal from is within a preset subtraction signal range, and when the value obtained by subtracting the background signal from the blank signal is not within the preset subtraction signal range, the operational amplifier By adjusting the resistance gain value of , a value obtained by subtracting the background signal from the blank signal may be within the preset subtracted signal range.

Meanwhile, in order to achieve the above object, a sample detection method using a nanowire FET according to an embodiment of the present invention includes a source electrode and a drain electrode, and a channel connecting the source electrode and the drain electrode A sample detection method performed by a sample detection device using at least one nanowire FET provided with a nanowire and a receptor, wherein the source electrode is electrically connected to a source electrode connector, and the drain electrode is electrically connected to a drain electrode connector. being connected; converting, by an I-V converter electrically connected to the drain electrode connector, a current flowing from the source electrode to the drain electrode into a voltage when a sample is applied to the channel; amplifying the voltage converted by the I-V converter by an operational amplifier; Converting, by an ADC, the voltage amplified by the operational amplifier into a digital count value; and detecting, by an MCU, samples included in the sample through the digital count value converted by the ADC.

Here, the sample detection device includes a DAC electrically connected to the source electrode connector, receiving a source voltage application command output from the MCU, and applying a source voltage to the source electrode according to the source voltage application command. The current flowing from the source electrode to the drain electrode may be caused by a source voltage applied to the source electrode by the DAC.

In addition, the sample detection device may include a power input unit receiving external power; and a battery charged by external power input to the power input unit, and the I-V converter, the operational amplifier, the ADC, the MCU, and the DAC can be operated by the power charged in the battery. there is.

The MCU obtains a background signal, which is a digital count value output by the ADC, in a state in which only the nanowire and the receptor are provided in the channel, before a sample is applied to the channel, and the background signal is present within a preset background signal range and if the background signal does not exist within the preset background signal range, a source voltage adjustment command may be output to the DAC so that the background signal exists within the preset background signal range. .

In addition, the MCU obtains a blank signal, which is a digital count value output by the ADC in a state in which a blank reagent is applied to the channel after the background signal is present within the preset background signal range, and the blank signal It is determined whether a value obtained by subtracting the background signal from is within a preset subtraction signal range, and when the value obtained by subtracting the background signal from the blank signal is not within the preset subtraction signal range, the operational amplifier By adjusting the resistance gain value of , a value obtained by subtracting the background signal from the blank signal may be within the preset subtracted signal range.

The present invention is provided with a source electrode connector and a drain electrode connector electrically connectable to the source electrode and the drain electrode of the nanowire FET, and also provides a current flowing from the source electrode to the drain electrode of the nanowire FET to an I-V converter, an operational amplifier, and an ADC. As it is configured to measure through, it is possible to detect the sample using the nanowire FET, and it is possible to miniaturize the device because it does not require large-scale microcurrent measurement equipment.

In addition, instead of arranging the nanowires so that the channel of the nanowire FET has a specific resistance, the present invention is configured to enable current measurement and sample detection by adjusting the background signal obtained in a state in which only the nanowire and the receptor are provided in the channel has been According to the present invention, it is possible to miniaturize the device because a separate resistance adjusting device is not required so that the channel of the nanowire FET has a specific resistance.

In addition, since the elements constituting the sample detection device of the present invention are operated by power charged in a battery rather than an external power source, current measurement and sample detection accuracy can be improved. In addition, since the present invention is configured to adjust the sensitivity of current measurement through a blank signal obtained in a state where a blank reagent is applied to the channel, this can also greatly contribute to improving the accuracy of current measurement and sample detection.

1A is a side perspective view of a sample detection device using a nanowire FET according to an embodiment of the present invention.
1B is a rear perspective view of a sample detection device using a nanowire FET according to an embodiment of the present invention.
FIG. 1C is a view showing a state in which a nanowire FET chip is accommodated in a chip accommodating unit of the sample detection device using the nanowire FET shown in FIG. 1A.
2 is a diagram schematically illustrating a nanowire FET chip accommodated in a chip accommodating unit.
3 is a diagram schematically illustrating an internal configuration of a sample detection device using a nanowire FET according to an embodiment of the present invention along with a nanowire FET chip.
4 is a flowchart of a sample detection method using a nanowire FET according to an embodiment of the present invention.
FIG. 5 is a graph illustrating a process of changing a digital count value output by an ADC when the sample detection method of FIG. 4 is used.

Hereinafter, a sample detection device and a sample detection method using a nanowire FET according to the present invention will be described in detail with reference to the accompanying drawings. The accompanying drawings are provided by way of example in order to sufficiently convey the technical idea of the present invention to those skilled in the art, and the present invention is not limited to the drawings presented below and can be embodied in any number of other forms. there is.

1A is a side perspective view of a sample detection device 1000 using a nanowire FET according to an embodiment of the present invention, and FIG. 1B is a side perspective view of a sample detection device 1000 using a nanowire FET according to an embodiment of the present invention. It is a rear perspective view. 1C is a view showing a state in which the nanowire FET chip 1 is accommodated in the chip accommodating part 120 of the sample detection device 1000 using the nanowire FET shown in FIG. 1A.

As shown in FIGS. 1A to 1C , the sample detection device 1000 using the nanowire FET according to an embodiment of the present invention may include a housing 110, a chip accommodation unit 120, and a display 130. there is.

The housing 110 serves to enclose internal components of the sample detection device 1000 to be described later. A chip accommodating part 120 may be provided on one side of the housing 110 , and the chip accommodating part 120 may be slidably coupled to the housing 110 .

The display 130 may be driven by a touch method, and items displayed on the display 130 may be controlled by the MCU 300 to be described later. For example, an open menu of the chip accommodating unit 120, a close menu of the chip accommodating unit 120, a current measurement menu, and the like may be displayed on the display 130 under the control of the MCU 300. can

When the user of the sample detecting device 1000 touches the open menu, the chip accommodating part 120 may protrude out of the housing 110 (see FIG. 1c), and when the user touches the close menu, the protruding chip accommodating part 120 may be inserted into the housing 110 (see FIG. 1A).

In addition, when the user touches the current measurement menu, a voltage is applied to the source electrodes 11, 21, and 31 to be described later, and accordingly, the source electrodes 11, 21, and 31 pass through the channels 12, 22, and 32 to the drain. Current flows through the electrodes 13, 23, and 33. At this time, current measurement and voltage conversion are performed by the I-V converters (230: 230-1, 230-2, 230-3), and amplification is performed by the operational amplifiers (240: 240-1, 240-2, 240-3). Then, conversion into a digital count value is performed by the ADCs 250 (250-1, 250-2, 250-3), and finally sample detection is performed by the MCU 300. Information on the samples detected by the MCU 300 may be displayed (sample amount, positive/negative, etc.) on the display 130 under the control of the MCU 300 .

As shown in FIG. 1B , a power input unit 410 to which a DC 8.4V adapter (not shown) can be coupled may be provided at the rear of the housing 110 . Power input to the power input unit 410 may be supplied to a power switch 440 or a battery 450 to be described later.

Meanwhile, the nanowire FET chip 1 may be accommodated in the chip accommodating unit 120 as shown in FIG. 1C. FIG. 2 is a diagram schematically illustrating the nanowire FET chip 1 accommodated in the chip accommodating unit 120 . As shown in FIG. 2 , the nanowire FET chip 1 may include one or more nanowire FETs 10 , 20 , and 30 .

The first nanowire FET 10 includes a source electrode 11 and a drain electrode 13, and a nanowire and a receptor are provided in a channel 12 connecting the source electrode 11 and the drain electrode 13. . The second nanowire FET 20 also includes a source electrode 21 and a drain electrode 23, and a nanowire and a receptor are provided in the channel 22 connecting the source electrode 21 and the drain electrode 23, , The third nanowire FET 30 also has a source electrode 31 and a drain electrode 33, and a nanowire and a receptor are provided in the channel 32 connecting the source electrode 31 and the drain electrode 33 there is.

Here, the source electrodes 11, 21, 31 and the channels 12, 22, 32 are electrically connected, and the channels 12, 22, 32 and the drain electrodes 13, 23, 33 are also electrically connected. there is.

In addition, the nanowire refers to a material such as Silicon Nanowire, Carbon Nanotube, Graphene, etc. provided in the channel 12 and capable of immobilizing a receptor, and the receptor refers to a sensing material immobilized on the nanowire and capable of receiving a sample. .

The channels 12, 22, and 32 serve as a kind of gate electrode in the nanowire FETs 10, 20, and 30. When only nanowires and receptors are provided in the channels 12, 22, and 32, the channel resistance (or the resistance between the source and drain electrodes) is very large, so that the current flows from the source electrode 11 to the drain electrode 13. less occur On the other hand, when the sample (DNA, RNA, antibody, hormone, cell, etc.) contained in the sample and the receptor bind, the channel resistance decreases and a relatively large current flows from the source electrode 11 to the drain electrode 13. will do In the present invention, it is determined whether or not the sample is present in the specimen by measuring the current generated when the sample included in the specimen binds to the receptor.

FIG. 3 is a diagram schematically illustrating an internal configuration of a sample detection device 1000 using nanowire FETs 10, 20, and 30 according to an embodiment of the present invention together with a nanowire FET chip 1. Referring to FIG.

Referring to FIG. 3 , the sample detection device 1000 using the nanowire FETs 10, 20, and 30 according to an embodiment of the present invention includes a source electrode connector 210 and a drain electrode connector 220 in a housing 110. ), an I-V converter 230, an operational amplifier 240, an ADC 250, and a controller 300.

As shown in FIG. 1C , when the nanowire FET chip 1 is accommodated in the chip accommodating part 120, the source electrodes 11, 21, and 31 of the nanowire FETs 10, 20, and 30 form a source electrode connector. (210: 210-1, 210-2, 210-3) and the drain electrodes 13, 23, 33 of the nanowire FETs 10, 20, 30 are connected to the drain electrode connector 220: 220- 1, 220-2, 220-3) are electrically connected.

At this time, when the sample is applied to the channels 12, 22, and 32 where the nanowires and receptors are provided, the channel resistance decreases as described above, and thus the source electrodes 11, 21, and 31 move to the drain electrodes 13, 23, and 33 current flow occurs.

The I-V converters 230: 230-1, 230-2, and 230-3 are electrically connected to the drain electrode connectors 220: 220-1, 220-2, and 220-3, and the channels 12, 22, 32), when a sample is applied, the current flowing from the source electrodes 11, 21, and 31 to the drain electrodes 13, 23, and 33 is measured, and the measured current is converted into a voltage. The reason why the I-V converter (230: 230-1, 230-2, 230-3) converts the current into voltage is that the channel resistance is reduced so that the source electrodes 11, 21, and 31 to the drain electrodes 13, 23, and 33 ), even if current flows, the magnitude of the generated current is still only a small level, so amplification is required.

The operational amplifiers 240: 240-1, 240-2, and 240-3 amplify the voltages converted by the I-V converters 230: 230-1, 230-2, and 230-3. In the present invention, the operational amplifiers 240 (240-1, 240-2, 240-3) may be composed of various types of amplifiers such as inverting amplifiers and non-inverting amplifiers. In addition, the operational amplifiers 240 (240-1, 240-2, 240-3) can be composed of only one amplifier, but when the resistor gain value needs to be sufficiently large, two or more amplifiers are connected in cascade. may be done

The ADCs 250: 250-1, 250-2, and 250-3 convert the voltages amplified by the operational amplifiers 240: 240-1, 240-2, and 240-3 into digital count values. If the ADCs (250: 250-1, 250-2, 250-3) are 16-bit ADCs, the total number of digital counts that the ADCs (250: 250-1, 250-2, 250-3) can represent is 65,536. . However, in reality, only some of these digital count values (eg, 26,000) may be used.

The MCU 300 detects samples included in the specimen through the digital count value converted by the ADC. For example, a digital count value for a case in which a sample is included in a sample may be preset in the MCU 300 . Accordingly, when the digital count value converted by the ADC (250: 250-1, 250-2, 250-3) is greater than or equal to the preset digital count value, the MCU 300 determines that the sample is included in the specimen, Information about the sample may be displayed through the display 130 . If the digital count value converted by the ADCs (250: 250-1, 250-2, 250-3) is less than the preset digital count value, the MCU 300 determines that the sample does not contain the sample, and Information about can be displayed through the display 130.

The sample detection device 1000 using the nanowire FET according to an embodiment of the present invention may include a power input unit 410 and a battery 450 .

As described above, the power input unit 410 receives external power from a DC 8.4V adapter, and the external power input to the power input unit 410 passes through the DPDT (Double Pole Double Through) relay 420 to the power switch ( 440) and the battery 450.

One end of the DPDT relay 420 is connected to the power input unit 410, and accordingly, the DPDT relay 420 supplies external power input to the power input unit 410 to the power switch 440 and the battery 450, or supply can be cut off.

The MCU 300 may control the DPDT relay 420. When the MCU 300 controls the DPDT relay 420 to connect the other end of the DPDT relay 420 to point A in FIG. 3, the external power input to the power input unit 410 is applied to the power switch 440 and the battery. It is supplied to 450. At this time, the external power input to the power input unit 410 is the I-V converter 230, operational amplifier 240, ADC 250, MCU ( 300) and a DAC 260 to be described later. That is, the sample detection device 1000 may be operated by external power input to the power input unit 410 . In addition, when the MCU 300 controls the DPDT relay 420 to connect the other end of the DPDT relay 420 to point A in FIG. charging takes place.

However, elements constituting the sample detection device 1000, that is, the I-V converter 230, the operational amplifier 240, the ADC 250, the MCU 300, and the DAC 260 are input to the power input unit 410. When driven by an external power supply, ripples and noise generated in the AC-DC conversion circuit (not shown) in the DC 8.4V adapter are introduced into the elements through the power input unit 410, and current-voltage conversion, voltage amplification, etc. In particular, since the size of the current flowing from the source electrodes 11, 21, and 31 to the drain electrodes 13, 23, and 33 is very fine on a micro or nano scale, ripples and noise may be introduced through the power input unit 410. In this case, whether or not the specimen contains the sample cannot be accurately detected.

Accordingly, in order to detect with high accuracy whether or not the sample is included in the sample, during operation of the sample detecting device 1000, such as detecting the sample included in the sample, external power is not used but the power charged in the battery 450. It is preferable to use only That is, the power charged in the battery 450 has significantly less ripple and noise than external power, so that it is possible to supply stable power to the elements constituting the sample detection device 1000, and as a result, the MCU 300 detects the sample. It is possible to detect with high accuracy whether or not the sample is included.

In this way, in order to use only the power charged in the battery 450 during the operation of the sample detection device 1000, the MCU 300 controls the DPDT relay 420 to move the other end of the DPDT relay 420 to point B in FIG. can be linked to In this case, external power input to the power input unit 410 is supplied to the resistor 431 and the light emitting diode 432, so that the light emitting diode 432 emits light. In addition, in this case, elements constituting the sample detection device 1000, that is, the I-V converter 230, the operational amplifier 240, the ADC 250, the MCU 300, and the DAC 260 are stored in the battery 450. The operation is performed by the charged power, and as a result, the elements are relatively less affected by ripple and noise, so that whether or not the sample is included in the specimen can be detected with high accuracy.

Meanwhile, the DACs 260: 260-1, 260-2, and 260-3 are electrically connected to the source electrode connectors 210: 210-1, 210-2, and 210-3, and output from the MCU 300 A source voltage application command is received, and a source voltage is applied to the source electrodes 11, 21, and 31 according to the source voltage application command. As a result, the current flowing from the source electrodes 11, 21, and 31 to the drain electrodes 13, 23, and 33 is transmitted through the DAC 260 (260-1, 260-2, 260-3) to the source electrodes 11, 21 , 31) is caused by the source voltage applied to .

Power charged in the battery 450 may be used for the operation of the DACs 260 (260-1, 260-2, 260-3). The MCU 300 basically outputs a source voltage application command to the DACs 260 (260: 260-1, 260-2, 260-3) when detecting a sample from the sample applied to the channels 12, 22, and 32. When the background signal is adjusted, a source voltage adjustment command may be output to the DACs 260 (260-1, 260-2, 260-3). Here, the source voltage adjustment command corresponds to an adjusted value of the source voltage application command, that is, an adjusted source voltage application command. As described above, according to the present invention, when the DACs (260: 260-1, 260-2, 260-3) are used both when detecting a sample from the sample applied to the channels 12, 22, and 32 and when adjusting the background signal, Because of this, it is economical compared to the case of separately providing a source voltage source, and control of the source voltage can also be easily achieved.

4 is a flowchart of a sample detection method using a nanowire FET according to an embodiment of the present invention, and FIG. 5 is a process of changing a digital count value output from an ADC when the sample detection method of FIG. 4 is used. it's a graph Hereinafter, a sample detection method using a nanowire FET according to an embodiment of the present invention will be described with further reference to FIGS. 4 and 5 .

A sample detection method using the nanowire FETs 10 , 20 , and 30 according to an embodiment of the present invention may be performed by the sample detection device 1000 described above. At this time, each of the nanowire FETs 10, 20, and 30 includes source electrodes 11, 21, and 31 and drain electrodes 13, 23, and 33, and the source electrodes 11, 21, and 31 and the drain electrode A nanowire and a receptor may be provided in the channels 12, 22, and 32 connecting the channels 13, 23, and 33.

In the sample detection method using the nanowire FET according to an embodiment of the present invention, first, the source electrodes 11, 21, and 31 are electrically connected to the source electrode connectors 210: 210-1, 210-2, and 210-3. A step of electrically connecting the drain electrodes 12, 22, and 32 to the drain electrode connectors 220: 220-1, 220-2, and 220-3 may be performed (S100). In other words, step S100 corresponds to a step in which the nanowire FET chip 1 is accommodated in the chip accommodating part 120 .

Basically, after the step S100, the sample is applied to the channels 12, 22, and 32, and the I-V converter (230: 230) electrically connected to the drain electrode connectors (220: 220-1, 220-2, 220-3) -1, 230-2, and 230-3 may convert a current flowing from the source electrodes 11, 21, and 31 to the drain electrodes 13, 23, and 33 into a voltage (S800).

After the step S800, the operational amplifiers 240: 240-1, 240-2, 240-3 amplify the voltages converted by the I-V converters 230: 230-1, 230-2, 230-3. It can (S900).

After the step S900, the ADC (250: 250-1, 250-2, 250-3) converts the voltage amplified by the operational amplifier (240: 240-1, 240-2, 240-3) into a digital count value It can be converted to (S1000).

After the step S1000, the MCU (300) can detect the sample included in the sample through the digital count value converted by the ADC (250: 250-1, 250-2, 250-3) (S1100 ).

However, each of the nanowire FETs 10, 20, and 30 constituting the nanowire FET chip 1 has a difference in electrical characteristics for each channel 12, 22, and 32, because the nanowire FET ( This is because there are limitations in the manufacturing process of 10, 20, and 30).

For example, when a nanowire material such as CNT (Carbon Nanotube) is dispersed in the channels 12, 22, and 32, a water dispersion technique using an organic solvent (EtOH, etc.) or water is applied. However, it is very difficult to evenly disperse the nanowire material in the channels 12, 22, and 32 due to strong hydrophobicity and insoluble aggregation characteristics of the nanowire material.

Due to the manufacturing limitations of the nanowire FETs 10, 20, and 30, electrical characteristics vary between the channels 12, 22, and 32 of the nanowire FETs 10, 20, and 30, and as a result, the nanowire FETs ( 10, 20, 30), it is difficult to manufacture constant channel resistance values. Until now, there is no way to physically compensate for this channel resistance difference. In some cases, the nanowire FETs 10, 20, and 30 are considered defective even though the channel resistance values of the nanowire FETs 10, 20, and 30 are out of the measurement range, and measurement is not impossible at all. may be discarded as well.

As an alternative to this, in the present invention, before the sample is applied to the channels 12, 22, and 32, the range measured by the ADC (250: 250-1, 250-2, 250-3) is measured by the MCU (300) We propose a method that can actively change. According to the present invention, since sample detection is possible through the nanowire FETs 10, 20, and 30 having various channel resistances, the production yield of the nanowire FET chip 1 can be increased, and the measurement limit can also be improved. be able to

To actively vary the range measured by the ADCs 250 (250-1, 250-2, and 250-3), after step S100, the MCU 300 connects the nanowires and receptors to the channels 12, 22, and 32. A background signal, which is a digital count value output by the ADCs 250 (250: 250-1, 250-2, 250-3) can be obtained (S200). When only the nanowires and receptors are provided in the channels 12, 22, and 32, the channel resistance is very high, so very fine signals flow from the source electrodes 11, 21, and 31 to the drain electrodes 12, 22, and 32.

As described above, it is difficult to evenly disperse the nanowire material in each channel 12, 22, and 32, and the channel resistance is different for each channel 12, 22, and 32. Accordingly, the channel 12, 22, and 32 In a state in which only the nanowire and the receptor are provided, currents flowing from the source electrodes 11, 21, and 31 to the drain electrodes 12, 22, and 32 are different. At this time, the current flowing from the source electrodes 11, 21, and 31 to the drain electrodes 12, 22, and 32 is converted into a voltage by I-V converters 230 (230-1, 230-2, and 230-3), and the conversion The resulting voltage is amplified by operational amplifiers 240 (240-1, 240-2, 240-3), and the amplified voltage is digitally counted by ADCs (250: 250-1, 250-2, 250-3) converted to a value

When the nanowire material is evenly distributed in each channel 12, 22, and 32, all digital count values converted by the ADCs 250 (250: 250-1, 250-2, 250-3) should be the same. Since it is difficult for the nanowire material to be evenly distributed in each channel 12, 22, 32, the digital count values converted by the ADCs 250 (250: 250-1, 250-2, 250-3) may be different. there is.

At this time, the digital count value converted by the ADC (250: 250-1, 250-2, 250-3) flows from the source electrodes (11, 21, 31) to the drain electrodes (12, 22, 32) regardless of the specimen. Since it is a current-based value, it corresponds to a background signal, and the MCU 300 can determine whether the background signal exists within a preset background signal range (S300).

When a sample is included in the specimen, the current flowing from the source electrodes 11, 21, and 31 to the drain electrodes 12, 22, and 32 is digital You can increase or decrease the count value. Accordingly, when the digital count value that can actually be used by the 16-bit ADC (250: 250-1, 250-2, 250-3) is, for example, 26,000, the MCU 300 calculates its median value of 13,000 A range of ±10% in may be preset as a background signal range.

As a result of the decision made by the MCU 300 in the step S300, when the background signal acquired in the step S200 does not exist within the preset background signal range, the MCU 300 converts the DACs 260: 260-1, 260-2, 260-3), a source voltage adjustment command is output so that the background signal exists within the preset background signal range (S400).

On the other hand, as a result of the decision made by the MCU 300 in the step S300, if the background signal obtained in the step S200 is within the preset background signal range, the MCU 300 converts the DACs 260: 260-1, 260-2, Step S500 is performed without outputting a source voltage adjustment command to 260-3).

For example, the channel resistance of the first nanowire FET 10 is R ₁ , the channel resistance of the second nanowire FET 20 is R ₂ , and the channel resistance of the third nanowire FET 30 is R ₃ , At this time, assuming that the channel resistance has a relationship of R ₂ > R ₁ > R ₃ , in a state in which only the nanowire and the receptor are provided in each channel 12, 22, and 32, in the source electrodes 11, 21, and 31 A current flowing through the drain electrodes 13, 23, and 33 is the smallest in the second nanowire FET 20 and the largest in the third nanowire FET 30.

At this time, the magnitude of the current flowing from the source electrode 11 to the drain electrode 13 of the first nanowire FET 10 is I ₁ , the I ₁ is converted into a voltage by the IV converter 230-1, and the operation When amplified by the amplifier 240-1 and converted to a digital count value by the ADC 250-1, the converted digital count value is within the range of -10% to +10% from the median value of 13,000 In this case, the MCU 300 does not output a source voltage adjustment command to the DAC 260-1.

The magnitude of the current flowing from the source electrode 21 to the drain electrode 23 of the second nanowire FET 20 is I ₂ , the I ₂ is converted into a voltage by the IV converter 230-2, and the operational amplifier When amplified by (240-2) and converted to a digital count value by ADC (250-2), the converted digital count value may exist within the range of less than -10% from the median value of 13,000, in this case The MCU 300 outputs a source voltage adjustment command to the DAC 260-2. Specifically, when the magnitude of the voltage applied to the source electrode 21 of the second nanowire FET 20 is V _S2 , the MCU 300 calculates that the converted digital count value is a median value of 13,000 to -10% A source voltage adjustment command for increasing I ₂ may be output to the DAC 260-2 so as to be within the range of +10% or less. In this case, the DAC 260-2 may apply a source voltage greater than V _S2 to the source electrode 21 according to the source voltage adjustment command.

The magnitude of the current flowing from the source electrode 31 to the drain electrode 33 of the third nanowire FET 30 is I ₃ , the I ₃ is converted into a voltage by the IV converter 230-3, and the operational amplifier When amplified by (240-3) and converted to a digital count value by ADC (250-3), the converted digital count value may exist within the range of +10% from the median value of 13,000, in this case The MCU 300 outputs a source voltage adjustment command to the DAC 260-3. Specifically, when the magnitude of the voltage applied to the source electrode 31 of the third nanowire FET 30 is V _S3 , the MCU 300 calculates that the converted digital count value is a median value of 13,000 to -10% A source voltage adjustment command for lowering the I ₃ to exist within a range of greater than or equal to +10% may be output to the DAC 260-3. In this case, the DAC 260-3 may apply a source voltage smaller than V _S3 to the source electrode 31 according to the source voltage adjustment command.

Even if the background signal levels of the nanowire FETs 10, 20, and 30 are matched by varying the source voltage in the above process, the amount of current change resulting from the same sample amount may not be displayed at the same level. That is, even if the same amount of sample is applied to each channel 12, 22, and 32, the magnitude of the current flowing from the source electrodes 11, 21, and 31 to the drain electrodes 13, 23, and 33 may be different. Therefore, the digital count values output by the ADCs 250-1, 250-2, and 250-3 may all be different. Therefore, it can be expressed as the same current change value for the same amount of sample only after going through a process of matching the sensitivity of measurement. To this end, a blank reagent having a specific concentration of electrolyte ions is added to each channel (12, 22, 32), and then ADCs (250-1, 250-2, 250-3) output the same digital count value. A step of automatically adjusting the resistor gain values of the operational amplifiers 240-1, 240-2, and 240-3 is performed.

More specifically, the MCU 300 controls the ADC 250-1 and 250-2 in a state in which a blank reagent is applied to the channels 12, 22, and 32 after allowing the background signal to exist within the preset background signal range. , 250-3) can obtain a blank signal that is a digital count value (S500). A blank reagent having a specific concentration of electrolyte ions has an effect of increasing a certain amount of current flowing from the source electrodes 11, 21, and 31 to the drain electrodes 13, 23, and 33.

After the step S500, the MCU 300 may determine whether a value obtained by subtracting the background signal from the blank signal is within a preset subtraction signal range (S600).

For example, a blank reagent is applied to the channels 12, 22, and 32 where nanowires and receptors are provided, and at this time, the blank reagent calculates the digital count value output by the ADCs 250-1, 250-2, and 250-3. Assuming that it has an effect of increasing by 100, the MCU 300 may preset a range of ±10% from the digital count value of 100 as a subtraction signal range (ie, a range of 90 or more and 110 or less).

As a result of the determination by the MCU 300 in the step S600, when the value obtained by subtracting the background signal from the blank signal obtained in the step S500 does not exist within the preset subtraction signal range, the MCU 300 operates the operational amplifier ( 240: Adjust the resistor gain values of 240-1, 240-2, and 240-3 so that a value obtained by subtracting the background signal from the blank signal is within the preset subtracted signal range (S700).

On the other hand, if the value obtained by subtracting the background signal from the blank signal obtained in step S500 as a result of the determination by the MCU 300 in the step S600 is within the preset subtraction signal range, the MCU 300 operates the operational amplifier ( Step S800 is performed without adjusting the resistor gain values of 240: 240-1, 240-2, and 240-3).

For example, in a state where a blank reagent that increases the digital count value by 100 is applied to the channel 12 of the first nanowire FET 10, the blank signal, which is the digital count value output by the ADC 250-1, is output by the MCU ( 300) obtained, and as a result determined by the MCU 300, the background signal (meaning the background signal of the first nanowire FET 10 obtained by the MCU 300 in step S200) was subtracted from the blank signal. We can assume that the value exceeds 110. In this case, the MCU 300 may adjust the resistance gain value of the operational amplifier 240-1 so that a value obtained by subtracting the background signal from the blank signal is within the preset subtraction signal range. Specifically, according to FIG. 3, the resistance gain value R _gain1 of the operational amplifier 240-1 is represented by R ₁₂ /R ₁₁ , and the MCU 300 adjusts the resistance gain value R _gain1 by lowering R ₁₂ or increasing R ₁₁ . Lowering adjustments can be made.

This time, in a state where a blank reagent that increases the digital count value by 100 is applied to the channel 22 of the second nanowire FET 20, the blank signal, which is the digital count value output by the ADC 250-2, is sent to the MCU 300 is obtained, and as a result of the determination by the MCU 300, a value obtained by subtracting the background signal (meaning the background signal of the second nanowire FET 20 acquired by the MCU 300 in step S200) from the blank signal is It can be assumed to be less than 90. In this case, the MCU 300 may adjust the resistance gain value of the operational amplifier 240-2 so that a value obtained by subtracting the background signal from the blank signal is within the preset subtraction signal range. Specifically, according to FIG. 3, the resistance gain value R _gain2 of the operational amplifier 240-2 is represented by R ₂₂ /R ₂₁ , and the MCU 300 increases the resistance gain value R _gain2 by increasing R ₂₂ or lowering R ₂₁ . Height can be adjusted.

In addition, in a state in which a blank reagent that increases the digital count value by 100 is applied to the channel 32 of the third nanowire FET 30, the blank signal, which is the digital count value output by the ADC 250-3, is sent to the MCU 300. is obtained, and as a result of determination by the MCU 300, a value obtained by subtracting the background signal (meaning the background signal of the third nanowire FET 30 obtained by the MCU 300 in step S200) from the blank signal is It can be assumed to exist within the range of 90 or more and 110 or less. In this case, the MCU 300 does not change the resistance gain value R _gain3 of the operational amplifier 240-3 because the value obtained by subtracting the background signal from the blank signal is within the preset subtraction signal range. may not be

In this way, as the MCU 300 controls the resistance gain of the operational amplifier 240-3, when a sample is applied to each channel 12, 22, 32, the source electrodes 11, 21, 31 ) to the drain electrodes 13, 23, and 33 can be predicted sufficiently, thereby improving the detection accuracy of the sample included in the specimen.

When the above-described steps S200 to S700 are performed, the background signal levels of the nanowire FETs 10, 20, and 30 can be adjusted and matched, and the current change amount resulting from the same sample amount can be displayed at the same level. Accordingly, when the above-described steps S800 to S1100 are performed after the step S700, the sample included in the specimen can be detected with high accuracy. The MCU 300 may determine whether a sample is included in the specimen, and display the determination result (sample amount, positive/negative, etc.) through the display 130 .

As described above, the present invention has been described by the limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art in the field to which the present invention belongs can make various modifications and transformation is possible Therefore, the technical spirit of the present invention should be grasped only by the claims, and all equivalent or equivalent modifications thereof will be said to fall within the scope of the technical spirit of the present invention.

1: nanowire FET chip
10: first nanowire FET
20; 2nd nanowire FET
30: third nanowire FET
11, 21, 31: source electrode
12, 22, 32: channels
13, 23, 33: drain electrode
110: housing
120: chip receiving unit
130: display
210 (210-1, 210-2, 210-3): source electrode connector
220 (220-1, 220-2, 220-3): drain electrode connector
230 (230-1, 230-2, 230-3): IV converter
240 (240-1, 240-2, 240-3): operational amplifiers
250 (250-1, 250-2, 250-3): ADC
260 (260-1, 260-2, 260-3): DAC
300: MCU
410: power input unit
420: DPDT relay
430 resistance
440: light emitting diode
450: battery
1000: sample detection device

Claims (10)

A sample detection device using at least one nanowire FET having a source electrode and a drain electrode, and having a nanowire and a receptor provided in a channel connecting the source electrode and the drain electrode,
a source electrode connector electrically connected to the source electrode;
a drain electrode connector electrically connected to the drain electrode;
an IV converter electrically connected to the drain electrode connector and converting a current flowing from the source electrode to the drain electrode into a voltage when a sample is applied to the channel;
an operational amplifier amplifying the voltage converted by the IV converter;
an ADC (Analog-Digital Converter) for converting the voltage amplified by the operational amplifier into a digital count value;
a micro controller unit (MCU) for detecting a sample included in the specimen through a digital count value converted by the ADC; and
A DAC (Digital-Analog Converter) electrically connected to the source electrode connector, receiving a source voltage application command output from the MCU, and applying a source voltage to the source electrode according to the source voltage application command,
The MCU,
Before the sample is applied to the channel,
Obtaining a background signal, which is a digital count value output by the ADC, when only the nanowire and the receptor are provided in the channel;
Determining whether the background signal exists within a preset background signal range;
When the background signal does not exist within the preset background signal range, a source voltage adjustment command is output to the DAC so that the background signal exists within the preset background signal range, nanowire FET Sample detection device using.
delete According to claim 1,
a power input unit receiving external power; and
Further comprising a battery that is charged by external power input to the power input unit,
The IV converter, the operational amplifier, the ADC, the MCU, and the DAC are operated by the power charged in the battery, the sample detection device using a nanowire FET.
delete According to claim 1,
The MCU,
After making the background signal exist within the preset background signal range,
Obtaining a blank signal, which is a digital count value output by the ADC in a state where a blank reagent is applied to the channel;
determining whether a value obtained by subtracting the background signal from the blank signal is within a preset subtraction signal range;
When the value obtained by subtracting the background signal from the blank signal is not within the preset subtraction signal range, the value obtained by subtracting the background signal from the blank signal is obtained by adjusting the resistance gain value of the operational amplifier. A sample detection device using a nanowire FET, characterized in that it exists within a set subtraction signal range.
A sample detection method performed by a sample detection device using at least one nanowire FET having a source electrode and a drain electrode and having a nanowire and a receptor provided in a channel connecting the source electrode and the drain electrode,
electrically connecting the source electrode to a source electrode connector and electrically connecting the drain electrode to a drain electrode connector;
converting, by an IV converter electrically connected to the drain electrode connector, a current flowing from the source electrode to the drain electrode into a voltage when a sample is applied to the channel;
amplifying the voltage converted by the IV converter by an operational amplifier;
Converting, by an ADC, the voltage amplified by the operational amplifier into a digital count value; and
Detecting, by an MCU, a sample included in the specimen through a digital count value converted by the ADC;
The sample detection device,
A DAC (Digital-Analog Converter) electrically connected to the source electrode connector, receiving a source voltage application command output from the MCU, and applying a source voltage to the source electrode according to the source voltage application command,
The current flowing from the source electrode to the drain electrode is caused by a source voltage applied to the source electrode by the DAC,
The MCU,
Before the sample is applied to the channel,
Obtaining a background signal, which is a digital count value output by the ADC, when only the nanowire and the receptor are provided in the channel;
Determining whether the background signal exists within a preset background signal range;
When the background signal does not exist within the preset background signal range, a source voltage adjustment command is output to the DAC so that the background signal exists within the preset background signal range, nanowire FET Sample detection method using.
delete According to claim 6,
The sample detection device,
a power input unit receiving external power; and
And a battery that is charged by external power input to the power input unit,
The IV converter, the operational amplifier, the ADC, the MCU, and the DAC are operated by power charged in the battery, a sample detection method using a nanowire FET.
delete According to claim 6,
The MCU,
After making the background signal exist within the preset background signal range,
Obtaining a blank signal, which is a digital count value output by the ADC in a state where a blank reagent is applied to the channel;
determining whether a value obtained by subtracting the background signal from the blank signal is within a preset subtraction signal range;
When the value obtained by subtracting the background signal from the blank signal is not within the preset subtraction signal range, the value obtained by subtracting the background signal from the blank signal is obtained by adjusting the resistance gain value of the operational amplifier. A sample detection method using a nanowire FET, characterized in that it exists within a set subtraction signal range.

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