Field effect transistor comprising mxene nanosheet and use thereof

Abstract

The present invention relates to a field effect transistor (FET) sensor capable of detecting contaminated mycotoxin in a food sample, wherein an antibody that specifically binds to a target material is fixed to an FET comprising an MXene nanosheet coated with L-cysteine, thereby measuring an electrical signal of the FET to accurately detect the target material and to quantitatively analyze the concentration of the target material in the food sample. Therefore, the FET sensor is provided as a food safety analysis means capable of analyzing contaminants in food.

Description

Field effect transistor comprising MXENE nanosheet and its use

[0001] The present invention relates to a field effect transistor (FET) sensor capable of detecting contaminated mycotoxins in food samples.

[0002] Field-effect transistors (FETs) are a key subfield of nano / microelectronics. FET sensors are electrochemical sensors whose electronic conductivity is governed by semiconductor materials, offering impressive advantages such as simple operation, miniaturization, and ultra-fast response times. In the FET sensor process, external analytes readily induce changes in the conductivity of the sensing channel material and modulate the dielectric material, which drives the electric field around the semiconductor. Because sensing channels are relatively rare in microsensor devices, mechanically robust materials have attracted considerable attention. Research is currently underway on sensors with unique mechanical properties for use in smart device technologies such as chips. One- and two-dimensional (1D and 2D) nanomaterials, such as silicon nanowires, carbon nanotubes, graphene, and transition metal sulfides, have proven to be promising channel materials for fabricating highly sensitive, real-time FET biosensors. Due to the unique properties of nanomaterial-based FET biosensors—high surface area, layered structure, and excellent electronic properties—efforts are continuing to utilize FETs for on-site and point-of-care diagnostic testing in diverse fields, including environmental, clinical, medical, and food analysis.

[0003] Aflatoxins (AF) are naturally occurring toxic secondary metabolites with low molecular weights (100–300 Da) and are mycotoxins synthesized by various molds, including molds belonging to the genus Aspergillus. Aflatoxins are frequently detected in food and feed and are one of the target detection substances for food and feed safety. Of the 18 aflatoxins discovered, aflatoxin B1 (AFB1), aflatoxin G1 (AFG1), aflatoxin B2 (AFB2), aflatoxin G2 (AFG2), and aflatoxin M1 (AFM1) have been proven to be human carcinogens and have been classified as Group I by the International Agency for Research on Cancer (IARC). Therefore, the development of a sensor capable of monitoring aflatoxins and detecting and quantifying the presence of aflatoxins in food is required.

[0004] The purpose of the present invention is to provide a food safety analysis means capable of analyzing contaminants in food using a field effect transistor (FET) sensor that can selectively and accurately detect target substances in real time using electrical signals and quantitatively analyze target substances.

[0005] The present invention provides a composite for a field effect transistor comprising MXene nanosheets; L-cysteine; and an antibody.

[0006] In addition, the present invention Ti3C2T x A field effect transistor comprising a composite including MXene nanosheets having a composition, L-cysteine, and an antibody; a substrate; and a microelectrode is provided.

[0007] In addition, the present invention provides a method for manufacturing a device for the field effect transistor for target material analysis.

[0008] In addition, the present invention provides a method for analyzing the safety of a food sample using the device for the field effect transistor.

[0009] According to the present invention, by fixing an antibody that specifically binds to a target substance to a field effect transistor (FET) including an MXene nanosheet coated with L-cysteine, the target substance can be accurately detected by measuring the electrical signal of the field effect transistor, and the concentration of the target substance in a food sample can be quantitatively analyzed, so that the field effect transistor sensor can be provided as a food safety analysis means capable of analyzing contaminants in food.

[0010] Figure 1 is a schematic diagram illustrating the operating procedure of an electrohydrodynamic (EHD)-printed field-effect transistors (FET) biosensor according to the present invention. Ultrathin MXene nanosheets printed by EHD were selected as the sensing material, and anti-AFB1 antibodies were linked to the MXene nanosheets via an L-cysteine ​​linker.

[0011] FIG. 2 shows the manufacturing process of ultrathin MXene nanosheets, where (a) is a schematic diagram of the manufacturing of ultrathin MXene nanosheets in the MAX step, (b) is a graphical illustration of the EHD printing process of MXene ink, (c) is a schematic diagram of electrohydrodynamic (EHD)-printed FETs, (d) is a transmission electron microscopy (TEM) image of a large volume of MXene used as ink in the EHD printing process, (e) and (f) are TEM images of ultrathin MXene nanosheets, (g) is an optical microscopy (OM) image of the EHD-printed MXene layer on the designed microelectrode, and (h) and (i) are cross-sectional field-emission scanning electron microscopy (FESEM) images.

[0012] Figure 3 shows the process of optimizing ultra-thin MXene nanosheets, (a) to (d) are 5 mg mL -1 (e) Optical microscopy (OM) images for various layers from 100 layers to 400 layers with MXene inks of different concentrations, (f) Current-voltage (I-V) characteristics of EHD printed MXene-based FET sensors of selected lamination processes, and (g) Current-voltage (I-V) characteristics of various layers (V ds = 0.4 V) are the results of measuring the transfer curves of the EHD printed MXene-based FET sensor. (g), (i), and (k) are about the electrical characteristics of the EHD printed FET sensor, and the I of the original (g), L-cysteine ​​modified (i), and anti-AFB1 antibody conjugated (k) FET sensor. ds - V dsThe output curves are shown with various gating voltages from -40 V to 40 V in 5 V steps. (h), (j), and (l) are drain-source voltages (V ) varying from 0.2 V to 1.0 V in 0.2 V steps. ds ) are transfer curves of the circular (h), L-cysteine ​​modified (j) and anti-AFB1 antibody bound (l) FET sensors at the antibody conjugation step.

[0013] Figure 4 shows the Ti3C2T EHD printed MXene-based FET sensor. x / GCE, L-cysteine / Ti3C2T x / GCE, anti-AFB1 antibody / L-cysteine / Ti3C2T x / GCE (glassy carbon electrode) and anti-AFB1 antibody / L-cysteine / Ti3C2T x / GCE with 10.0 mM K3[Fe(CN)6] 3- / 4- 0.1 μg mL in PBS (pH 7.4) -1 Electrochemical properties were analyzed after culture in the presence of AFB1. (a) Cyclic voltammograms and (b) Nyquist diagrams.

[0014] Figure 5 is a graph showing the evaluation of the detection ability of the EHD printed MXene-based FET sensor for AFB1 (aflatoxin B1), (a) is a schematic diagram of the EHD printed FET sensor for detecting AFB1 in water, (b) is a graph showing the real-time response of the EHD printed FET sensor to AFB1 at concentrations of 0.01 ppb to 80 ppb, (c) is a graph showing a scatter plot of the relative response ((I0- I) / I0) versus AFB1 concentration using a linear fitting curve at t = 100 s, (d) is a graph showing the real-time response of the EHD printed FET sensor when ZEA (zearalenone), OTA (ochratoxin A), AFG2 (aflatoxin G2), AFG1 (aflatoxin G1), AFB2 (aflatoxin B2), and AFB1 (aflatoxin B1) are continuously added, and (e) is a graph showing the real-time response of the EHD printed FET sensor. This graph compares the response ((ΔI) / I0, %) at 1 ppb of various mycotoxins.

[0015] Figure 6 shows the results of HPLC analysis to compare the detection ability of AFB1 (aflatoxin B1) of EHD printed MXene-based FET sensors.

[0016] Figure 7 shows the results of analyzing the detection ability of AFB1 (aflatoxin B1) according to the storage period to evaluate the stability of the EHD printed MXene-based FET sensor.

[0017] Figure 8 is a schematic diagram showing the molecular structure and energy of the EHD printed MXene-based FET sensor. (a) is the molecular structure of AFB1 (aflatoxin B1), and (b) is the molecular structure of L-cysteine. The interaction models and corresponding adsorption energies (E) of each MXene and AFB1 and L-cysteine ​​are shown. ads), (c) and (f) are for Ti3C2F2MXene, (d) and (g) are for Ti3C2O2MXene, and (e) and (h) are for Ti3C2(OH)2MXene.

[0018] Figure 9 shows the results of detecting AFB1 (aflatoxin B1) in a peanut butter sample, (a) is a schematic diagram of an EHD printed FET sensor for AFB1 detection, (b) is a real-time response of the EHD printed FET sensor to AFB1 in a peanut butter sample, and (c) is an HPLC chromatogram of 100 ppb AFB1 added to the peanut butter sample.

[0019] Figure 10 shows the results of detecting AFB1 (aflatoxin B1) in a meju sample, (a) is a schematic diagram of an EHD printed FET sensor for AFB1 detection, (b) is a comparison of the response signals between normal meju and meju samples contaminated with Aspergillus flavus, (c) is a real-time response of the EHD printed FET sensor to AFB1 in a meju sample contaminated with A. flavus, (d) is a dose-dependent response curve of the EHD printed FET sensor to AFB1, and (e) is an HPLC chromatogram of about 20 ppb AFB1 in a meju sample contaminated with A. flavus.

[0020] The terms used in this specification have been selected from widely used, current terms, taking into account the functions of the present invention. However, these terms may vary depending on the intentions of those skilled in the art, precedents, the emergence of new technologies, etc. Furthermore, in certain cases, terms may be arbitrarily selected by the applicant, and in such cases, their meanings will be described in detail in the relevant description of the invention. Therefore, the terms used in this invention should not be defined simply as names, but rather based on their inherent meanings and the overall content of the present invention.

[0021] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0022] Hereinafter, the present invention will be described in more detail.

[0023]

[0024] The present inventors have developed a field effect transistor (FET) sensor capable of detecting contaminated mycotoxins in food samples, and have developed a FET sensor comprising MXene nanosheets and an antibody that specifically binds to the target substance, mycotoxin. To this end, MXene nanosheets were electrohydrodynamic jet-printed on a FET substrate, the MXene nanosheets were coated with L-cysteine, and the antibody was immobilized on the L-cysteine ​​coating layer using a peptide bond-inducing catalyst, thereby manufacturing a FET sensor capable of detecting the target substance, mycotoxin. The present invention was completed by confirming that mycotoxins were qualitatively and quantitatively analyzed by applying a mycotoxin standard sample, an artificial contamination sample, and a mold-contaminated food sample to the FET sensor.

[0025] In the present invention, the MXene is a conductive material utilized in the development of wearable sensors and biosensors. MXene is a two-dimensional layered material in which carbon (C) or nitrogen (N) is bonded to a transition metal. It is manufactured by selectively etching only the aluminum layer in a MAX phase that forms an intermediate layer, such as aluminum (Al).

[0026] In the present invention, the composition of the MXene is M n+1 X n T x is the base, where M is a transition metal, Ti, X is carbon (C), and T x The functional group of MXene is oxygen (O), hydroxyl group (OH) or fluorine (F). Specifically, the MXene of the present invention is Ti3C2T x It has a composition.

[0027] In the present invention, a field effect transistor (FET) is a device in which an electric field is formed by a voltage applied to the transistor, and a current is controlled by the strength of the electric field. The FET has a current path called a channel that is controlled by an external electric field, and includes a source electrode, which is an electron injection electrode, a drain electrode, which is an electron drain electrode, and a gate electrode that controls the external electric field. Specifically, the FET can control the current of the source electrode and the drain electrode by applying a voltage to the gate electrode to create a gate through which electrons (-) or holes (+) flow by the magnetic field of the channel.

[0028] In the present invention, EHD printing (electrohydrodynamic printing) is a technology that uses an electric field to eject and spray ink electrohydrodynamically. Printing applies voltage to the nozzle section and ejects and sprays ink through the lower electrode.

[0029] In the present invention, the antibody is also called immunoglobulin, and is a substance that specifically binds to an antigen and causes an antigen-antibody reaction. The antibody is a Y-shaped protein, in which one long chain (heavy chain) and one small chain (light chain) are paired to form one axis of the Y, and the other axis is symmetrically bound by an identical pair of heavy chains and light chains. The specificity of the antibody is determined according to the complementarity determining regions (CDRs), which are the parts of each chain that contribute to binding to the antigen.

[0030] The present invention provides a composite for a field effect transistor comprising MXene nanosheets; L-cysteine; and an antibody.

[0031] The above MXene nanosheets are 1 mg mL -1 5 mg mL -1 A two-dimensional layered structure is produced by electrohydrodynamic jet-printing (EHD) of MXene ink of a concentration, and the two-dimensional layered structure of the MXene nanosheet is 200 to 400 layers. The layer of the MXene nanosheet means one printing of the MXene ink.

[0032] The above Ti3C2T x In the composition above T x The surface functional group of MXene nanosheets is fluorine (F) or oxygen (O).

[0033] The above complex is coated with the L-cysteine ​​on the surface of the MXene nanosheet, and the antibody is bound to the L-cysteine ​​coating layer.

[0034] The above antibody is an antibody that specifically binds to a mycotoxin, and the mycotoxin is at least one mycotoxin selected from aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, zearalenone, and ochratoxin A.

[0035] In addition, the present invention Ti3C2T x A field effect transistor comprising a composite including MXene nanosheets having a composition, L-cysteine, and an antibody; a substrate; and a microelectrode is provided.

[0036] The above substrate is composed of a p-type Si / SiO2 wafer and is coated with chromium (Cr) and gold (Au).

[0037] In the above microelectrode, the drain electrode and the source electrode are made of high-purity gold, and the gap is 3 μm.

[0038] In addition, the present invention provides a method for producing Ti3C2T from MAX powder having a Ti3AlC2 composition using an aluminum etching method. xA method for manufacturing a device for a field effect transistor for analyzing a target substance is provided, comprising: a step of manufacturing an MXene ink having a composition (step 1); a step of manufacturing an MXene nanosheet by electrohydrodynamic jet-printing the MXene ink on a substrate between a drain electrode and a source electrode in a field effect transistor device (step 2); a step of immersing a device including the MXene nanosheet in an L-cysteine ​​solution to coat the surface of the MXene nanosheet with the L-cysteine ​​(step 3); a step of treating the device coated with the L-cysteine ​​with a catalyst for inducing a peptide bond (step 4); and a step of treating the device of the step 4 with an antibody that specifically binds to the target substance to immobilize the antibody on the L-cysteine ​​coating layer (step 5).

[0039] In the first step, MAX powder having a Ti3AlC2 composition is etched, and the resulting MXene sheet is subjected to ultrasonic treatment to produce MXene ink.

[0040] The above second step is the concentration of the MXene ink is 1 mg mL -1 5 mg mL -1 , and is performed under the conditions that the flow rate of the MXene ink is 0.45 μL / min, the working distance between the printing nozzle and the substrate is 600 μm, and the printing speed is 100 mm / mL.

[0041] In the fourth step, the catalyst for inducing the peptide bond is at least one catalyst selected from among 1-ethyl-3-(3-dimethylamino) propyl carbodiimide hydrochloride and N-hydroxysuccinimide.

[0042] The above fifth step is performed at a temperature of 25°C to 37°C.

[0043] In addition, the present invention provides a method for analyzing the safety of a food sample, comprising the steps of: preparing a food sample as an analysis sample by adding an aqueous solution to the food sample; applying the analysis sample to a field effect transistor device for analyzing a target substance manufactured according to the manufacturing method of any one of claims 11 to 15; and measuring an electrical signal of the field effect transistor device to determine whether the target substance is present in the food sample.

[0044] When the target material is a mycotoxin, the antibody included in the field effect transistor device is an antibody that specifically binds to the mycotoxin, and the mycotoxin is at least one mycotoxin selected from aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, zearalenone, and ochratoxin A.

[0045] The above electrical signal is calculated by measuring the drain-source potential of the device for the field effect transistor using the following mathematical expression 1.

[0046] [Mathematical Formula 1]

[0047] ΔI / I0(%)= [(I - I0) / I0] X 100

[0048] Here, I is the current detected in real time when the above analysis sample is applied, I0 is the initial current before the above analysis sample is applied, and ΔI represents the current change.

[0049] The above analysis method may additionally include a step of applying a standard sample of a target material to the device for the field effect transistor to create a calibration curve for the electrical signal (ΔI / I0(%)) according to the concentration of the target material; and a step of measuring the concentration of the target material included in the analysis sample using the calibration curve.

[0050] Hereinafter, to aid understanding of the present invention, experimental examples and examples will be described in detail. However, the following experimental examples and examples are merely illustrative of the present invention and are not intended to limit the scope of the present invention. The experimental examples and examples of the present invention are provided to more fully explain the present invention to those of average skill in the art.

[0051]

[0052] <Experimental Example> Experimental Materials and Methods

[0053] The following experimental examples are intended to provide experimental examples commonly applied to each embodiment according to the present invention.

[0054]

[0055] 1. Microelectrode fabrication

[0056] Microelectrodes with an electrode gap of 3 μm were fabricated using standard photolithography. Six-inch p-type (boron-doped) silicon wafers with a 100 nm thick SiO2 heat-resistant coating were selected as substrates. The Si / SiO2 wafers were washed with acetone and isopropyl alcohol, dried under a N2 stream, and dehydrated on a hot plate at 200°C for 10 min. After cooling to room temperature, photoresist material was spin-coated and prebaked at 110°C for 2 min to remove the solvent. The substrates were exposed to UV light through a mask using a mask aligner, washed with distilled water, developed with a developer (AZ 400K), dried under a N2 stream, and post-annealed on a hot plate. The developed substrate was coated with 20 nm thick Cr and 180 nm thick Au layers using an e-beam evaporator. Finally, the substrate was immersed in a remover solution (AZ 100) using the lift-off method, washed with acetone and isopropyl alcohol, and dried under a N2 stream. The electrode wafer prepared as described above was used as a substrate for a field-effect transistor (FET).

[0057]

[0058] 2. Fabrication of MXene ultra-thin films using electrohydrodynamic jet printing

[0059] 2-1. Ultra-thin Ti3C2T x Manufacturing of MXene nanosheets

[0060] Ultra-thin Ti3C2T xMXene nanosheets were synthesized from Ti3AlC2MAX powder (molecular weight: 93.92, ~400 mesh, SY Innovation Co. Ltd., Gyeonggi-do) by the aluminum etching method. HF (49%, Samjeon Pure Chemical Co., Ltd., Korea) was added to the Al layer (1 g) of the MAX powder and reacted at 25°C for 36 h with continuous stirring. The resulting mixture was centrifuged at 10,000 rpm for 15 min, washed with distilled water, and dried in an oven at 60°C. A large amount of Ti3C2T x was cross-cut by sonication with dimethyl sulfoxide for 12 h (power: 100 W, time: 30 min). Finally, the ultra-thin Ti3C2T x Nanosheets were washed with distilled water to remove contaminants and stored using nitrogen gas.

[0061] 2-2. Ultra-thin Ti3C2T x Characterization of MXene nanosheets

[0062] Ultra-thin Ti3C2T xThe morphology and chemical composition of MXene nanosheets were analyzed using field-emission transmission electron microscopy (FE-TEM) (Philips CM 200, Eindhoven, Netherlands) with energy-dispersive X-ray spectroscopy (FE-SEM) (Hitachi S4800, Chiyoda-ku, Tokyo, Japan) and field-emission transmission electron microscopy (FE-TEM) with an FEI / Tecnai G2 F20 S-Twin transmission electron microscope at an accelerating voltage of 200 kV (Philips CM 200, Eindhoven, Netherlands). X-ray diffraction spectra of the samples were obtained using a Philips PANalytical X'Pert PRO diffractometer (MRD model, D / MAX-2200H, Malvern Panalytical Ltd., Malvern, WR, UK) with a high-strength ceramic sealed tube (3 kW) X-ray source (Cu Kα, 30 mA, 40 kV). Raman analysis of the samples was performed using XploRA Plus (HORIBA France SAS, Palaiseau, CS, France) with a thermoelectric air-cooled charge-coupled device detector. The samples were excited with a Yttrium Aluminum Garnet (YAG) laser at 532 nm, and the resolution was 3 cm -1and the acquisition time was 2 s. The atomic properties of the samples were analyzed using X-ray photoelectron spectroscopy (ESCALAB 250 System, Thermo Fisher Scientific, UK). The surface morphology of the electrohydrodynamically (EHD) printed MXene layers was analyzed using OM (Nikon ECLIPSE LV100ND, Nikon Metrology, Leuven, Belgium) and field-effect scanning electron microscopy (FE-SEM). Current-voltage electrical measurements were performed using a Keithley 4200 semiconductor analyzer (Tektronix, Inc., Beaverton, OR, USA).

[0063] The ultra-thin MXene solution (ink) prepared as described above was printed on microelectrodes using an electrohydrodynamic (EHD) jet printer. Before printing, the substrate was washed with boiling isopropyl alcohol, ultrasonicated (100 W, 10 min), and then exposed to UV light for 10 min. Ethanol was used for EHD printing. The MXene solution (5 mg mL -1 ) was filled into a glass syringe and printed at an electrode spacing (3 μm) with a solution flow rate of 0.45 μL / min under optimal printing conditions (working voltage: 1.36 V, working distance: 600 μm, printing speed: 100 mm / mL). Finally, the device was annealed at 110°C for 15 min in air to fabricate electrohydrodynamic (EHD) printed field-effect transistors (FETs).

[0064] 2-3. Electrochemical Measurement

[0065] Cyclic voltammogram (CV) and electrochemical impedance spectroscopy (EIS) measurements were performed using a multichannel electrochemical workstation (ZIVE MP1, WonATech Co., Ltd., Seoul, Korea). The measurements were performed using a conventional three-electrode system consisting of a modified glassy carbon electrode (GCE) as a working electrode, a platinum wire as an auxiliary electrode, and a saturated calomel electrode (SCE) as a reference. Electrochemical measurements were performed using 10.0 mM K3[Fe(CN)6] as a redox probe. 3- / 4- was carried out in PBS (pH 7.4) containing . For the measurement, GCE was used as an ultra-thin Ti3C2T x Modified with MXene nanosheets. MXene / GCE was immersed in a 0.1 M L-cysteine ​​solution for 1 h to functionalize the carboxyl groups on the electrode surface. After thoroughly washing the L-cysteine / MXene / GCE with distilled water, the carboxyl groups on the electrode were activated by immersing it in EDC (0.4 M) and NHS (0.1 M).

[0066]

[0067] 3. Immobilization of anti-AFB1 antibodies on the surface of MXene nanosheets.

[0068] As described above, in order to fabricate a field-effect transistor (FET) device fabricated by electrohydrodynamic (EHD) printing for mycotoxin detection, a mycotoxin antibody was immobilized on the MXene nanosheets of the device to fabricate anti-AFB1 antibody / L-cysteine / MXene. The FET device fabricated by electrohydrodynamic (EHD) printing was immersed in 0.1 M L-cysteine ​​(Sigma-Aldrich, Co., St. Louis, MO, USA) at 25°C for 1 hour and then washed three times with distilled water. Afterwards, the -COOH and -NH2 functional groups were activated (functionalized) by immersing the device in phosphate buffer saline (PBS) containing 0.4 M 1-ethyl-3-(3-dimethylamino) propyl carbodiimide hydrochloride and 0.1 M N-hydroxysuccinimide for about 20 minutes. The functionalized FET device was exposed to a PBS (pH 7.4) solution containing 150 μM anti-AFB1 antibody (Sigma-Aldrich, Co., St. Louis, MO, USA) at 25°C to 37°C for 5 hours. The electrode was washed with PBS to remove unbound antibody. To impart selectivity for the target mycotoxin, the device was immersed in PBS containing 2.5% BSA for 40 minutes to block the active sites other than the antibody. After rinsing several times with PBS, the manufactured FET device for mycotoxin detection was dried at room temperature and stored at 4°C.

[0069]

[0070] 4. Analysis of electrical characteristics of FET devices

[0071] Electrical performance was measured using a Keithley-4200 semiconductor analyzer (Keithley 4200 SCS, Tektronix, Inc., Beaverton, OR, USA) equipped with a probe station providing electrical connection to gold microelectrodes. During the measurements, the bias voltage was maintained at 0.1 mV, and the normalization of the detected electrical signal was calculated using the following mathematical equation (1).

[0072] [Mathematical Formula 1]

[0073] ΔI / I0= (I - I0) / I0

[0074] Here, I is the detected real-time current, I0 is the initial current, and ΔI represents the current change.

[0075] The limit of detection (LOD) was calculated as shown in Equation 2 below.

[0076] [Equation 2]

[0077] LOD = (3 × SD) / m

[0078] Here, SD is the standard deviation of the mean blank signal (control) and m is the slope of the linear calibration curve.

[0079]

[0080] 5. Calculation method

[0081] Density functional theory (DFT) calculations were performed in the Vienna Ab initio simulation package. The Perdew, Burke, and Ernzerhof parameterizations using the generalized gradient approximation were utilized to improve the equilibrium properties of various systems. A 4 × 4 × 1 monolayer MXene supercell model was constructed to represent the MXene surface, which was fully saturated with functional groups. The cutoff energy was fixed at 500 eV, and the electron-ion interactions were achieved via projector-enhanced wave propagation. The dispersion energies and H-bonding for the adsorption of L-cysteine ​​and AFB1 molecules on the MXene surface were described using Grimme's D3 correction.

[0082]

[0083] 6. Prepare contaminated food samples (peanut butter)

[0084] Peanut butter sample (purchased from a local supermarket in Gyeongsan-si, Gyeongsanbuk-do, South Korea) was 100 μg kg -1 AFB1 (aflatoxin B1) was mixed. The sample was then left at room temperature for 3 days. Three independent experiments were performed. For sample collection, peanut butter with AFB1 was systematically mixed, and a 10 g sample was collected. The collected peanut butter sample was added to 50 mL of 80% methanol, homogenized at 10,000 rpm for 2 minutes, and shaken at room temperature for 1 hour. The sample was then filtered using Whatman filter paper, and the filtrate was used for FET analysis.

[0085]

[0086] 7. Preparation of contaminated food samples (meju)

[0087] Aspergillus flavus KACC 45470, a toxic fungal strain (National Institute of Agricultural Sciences, Agricultural Microbiology Bank, Suwon, Gyeonggi-do), was cultured in potato dextrose broth (PDB) at 28°C in a shaking incubator (150 rpm) for 7 days. To make meju, soybeans were thoroughly washed, soaked in water for 8 h, and boiled at 110°C for 1.5 h. The boiled soybeans were mashed, mixed with an appropriate amount of the calculated A. flavus culture medium, and fermented by incubation at 30°C for more than 15 days. AFB1 was extracted from meju samples for FET analysis.

[0088]

[0089] 8. Extraction of AFB1 from food samples for HPLC analysis

[0090] The methanolic filtrates of the meju and peanut butter samples were diluted eightfold with 0.1% Tween 20 aqueous solution. The diluted filtrates were filtered again using a 1.6 μm glass fiber filter to obtain a clear solution. A 20 mL solution was then passed through an aflatoxin affinity column (VICAM, Milford, MA, USA) to adsorb aflatoxins. The affinity column was washed with distilled water (10 mL) to remove impurities. After 0.5 h, the adsorbed aflatoxins were separated and collected using 4 mL of methanol containing 0.1% acetic acid. All collected fractions were evaporated using N2 gas at 50°C. The dried samples were reconstituted in 600 μL of a 20% acetonitrile:trifluoroacetic acid (4:1 ratio) solution. Finally, the solution was filtered using a 0.2 μm syringe filter for comparative analysis using standard high-performance liquid chromatography (HPLC). AFB1 in food samples was quantified using an UltiMate 3000 HPLC system (Thermo Fisher Scientific, Waltham, MA, USA) at a column temperature of 30°C using a Cloversil-C18 column (4.6 mm × 250 mm, pore size 5 μm).

[0091]

[0092] Example 1. Preparation of ultra-thin MXene nanosheets

[0093] Ultra-thin MXene nanosheets were prepared by immersing MAX powder in HF (hydrofluoric acid), followed by insertion and probe sonication, as shown in Fig. 2(a). The MXene nanosheets were stored in an alcohol medium for long-term storage. Due to the low surface tension of ethanol, a Taylor cone was formed during the EHD printing process. As a result, the conductivity of the MXene nanosheets increased slightly (approximately 8900 S / cm) compared to other organic solvents. These characteristics are essential for practical applications of all printed electronic devices. Ultra-thin FET nanosheets were prepared by mixing the MXene ink for EHD printing with ethanol, as shown in Fig. 2(b). The overall fabrication process of the ultra-thin MXene-based FET according to the present invention is shown in Fig. 2. Transmission electron microscopy (TEM) images of the ultra-thin MXene-based FET are shown in Figs. 2(e) and (f). An image of the bulk MXene with stacked sheet layers is shown in Fig. 2(d).

[0094]

[0095] Example 2. Optimization of MXene nanosheets

[0096] Before engineering practical field-effect transistors (FETs) based on ultrathin MXene, electrical characterization of the microelectrodes was performed to ensure that the printed cycles, called nanosheet layers, exhibit characteristics suitable for low-voltage and electrically stable operation of FETs. The back-gate EHD-printed MXene FET device is shown in Fig. 2(c). The drain and source electrodes were fabricated with high-purity gold photolithographically painted on a Si wafer with a gap of 3 μm. Thermally processed SiO2 was used as insulation between the electrodes and the back gate to prevent current leakage from the electrodes. The jet-printing nozzle was positioned on the source / drain electrodes and applied a gentle force to move toward the next electrode at a constant speed to achieve uniform printing, as shown in Fig. 2(b). 1 mg mL -1 5 mg mL -1 Different layers of MXene solutions with different concentrations were EHD printed onto gold microelectrodes coated on heavily doped p-type Si / SiO2 substrates. 1 mg mL -1 and 3 mg mL -1 When using low concentration inks such as 5 mg mL, no observable layer was detected under a microscope. Also, as shown in (a) to (d) of Fig. 3, 5 mg mL -1The XMene ink with a concentration of 100 to 400 formed distinct printable layers. The OM images of various EHD printed layers confirmed that the nanosheets were uniformly layered on the gap and electrode without a coffee-ring effect, as shown in Fig. 2(g). In addition, the cross-sectional analysis of the printed product of the designed electrode was performed using field-emission scanning electron microscopy (FESEM), and highly aligned nanoflakes were confirmed, as shown in Fig. 2(h) and (i). The thickness of the 300-layer printed layer was confirmed to be approximately 976 nm.

[0097] To test the suitability of MXene layers for FETs, selected layers (100, 200, 300, and 400 layers, as shown in (a) to (d) of Fig. 3) were printed. Current-voltage (I-V) plots, such as output and transfer curves, for various layers of EHD-printed MXene-based FET devices are shown in (e) and (f) of Fig. 3. All devices with various printed layers exhibited perfectly linear I-V characteristics, and Ti3C2T x Excellent Ohmic contact between MXene nanosheets and gold microelectrodes was observed. Ti3C2T x The resistance of MXene FET is 10 3 -10 9 Ω was calculated. The 100-layer and 200-layer EHD printed layer devices exhibited very high resistance. As shown in Fig. 3(e) and (f), increasing the printed layer to 300 layers improved the film thickness, which resulted in an ideal resistance range and higher I on / I offThe current flow through the channel was promoted by the ratio. As shown in Fig. 3(f), p-type transfer characteristics were observed in all cycles of the printed layer, and the external gate field showed a significant conductivity change in the EHD printed FET device. The results confirmed that the case printed with 300 layers during the EHD printing process has high compatibility to produce excellent FETs with high electrical conductivity. The transfer characteristics of the EHD printed FET were V gs When sweeping from -40 V to +40 V, I ds showed a linear decrease in Ti3C2T. The above results x It shows the p-type semiconductor properties of MXene, which indicates that most of the charge carriers are holes. When MAX powder is treated with HF, the surface functional groups (T) of MXene nanosheets are formed during the synthesis process. x ) is fluorine (F) or oxygen (O), and forms Ti vacancies / edge defects.

[0098]

[0099] Example 3. Fabrication of a FET sensor for detecting mold toxins

[0100] Referring to the results of Example 2 above, an EHD-printed FET (field effect transistor) sensor for mycotoxin detection was fabricated to include 300-layer patterned MXene nanosheets exhibiting high conductivity and ideal resistance. L-cysteine ​​was used as a linker, and L-cysteine ​​was used as a surface functional group (T) of the MXene nanosheets. x ) was combined with. The anti-AFB1 antibody targeting AFB1 (aflatoxin B1), the most widely used mycotoxin, was used as a receptor that recognizes mycotoxins.

[0101] To confirm the presence and modification of anti-AFB1 antibodies on the surface of MXene nanosheets, Ti3C2T x FET sensor, Ti3C2T with L-cysteine ​​attached x / L-cysteine ​​FET sensor, Ti3C2T with anti-AFB1 antibody attached x Electrical measurements of the / L-cysteine / anti-AFB1 antibody FET sensor were performed. The drain-source voltages (V) on the field effect transistor (FET) ds ) as the drain-source current (I ) changes over a voltage range of -5.0 V to +5.0 V. ds )(μA) change in I ds - V ds The output curve was written as follows. For each sensor, the gate-source voltages (V gs ) by changing from -40 V to 40 V. ds - V ds The output curves were drawn. As shown in (g), (i), and (k) of Fig. 3, Ti3C2T x When L-cysteine ​​is bound to the surface of the MXene nanosheet, or when L-cysteine ​​and anti-AFB1 antibody are bound, dI ds / dV ds The slope was found to decrease. In addition, Ti3C2T x FET sensor and Ti3C2T x / L-cysteine ​​FET sensor has a drain-source voltage (V) from -5.0 V to +5.0 V ds ) range of gate-source voltage (V gs ) even if I change it ds - V ds The plots formed curves that overlapped exactly. On the other hand, Ti3C2T x / L-cysteine / anti-AFB antibody sensor has a drain-source voltage (V) from -5.0 V to +5.0 V ds ) range of gate-source voltage (V gs ) increases I ds - V ds The slope of the plot was reduced, showing a clear separation of the curves. That is, Ti3C2T with anti-AFB1 antibody conjugated x When the gate voltage in the / L-cysteine / anti-AFB antibody sensor was changed from negative to positive, the drain current showed a tendency to decrease, and it was confirmed that the field-effect response according to the gate change was clearly observed. The above results are for Ti3C2T x / L-cysteine / anti-AFB antibody The anti-AFB1 antibody was successfully immobilized on the sensor, demonstrating its operation as a field effect transistor.

[0102] To evaluate the effects of surface functionalization and immobilization of the above sensors, transfer characteristics were measured. Each sensor was subjected to drain-source voltages (V ds ) is used as 0.2 V, 0.4 V, 0.6 V, 0.8 V or 1 V, and the gate voltage (V) is in the range of -40 V to +40 V. g ) is the drain current (I ) that saturates at the value ds )(μA) was measured. As shown in (h), (j) and (l) of Fig. 3, Ti3C2T x Sensor, Ti3C2T x / L-cysteine ​​sensor and Ti3C2T x / V in L-cysteine / anti-AFB antibody sensor respectively ds Every V g The drain current values ​​were measured according to the change in Ti3C2T x / L-cysteine / anti-AFB antibody sensor is Ti3C2T x / Same V than L-cysteine ​​sensor ds In I ds showed a decreasing trend. These I ds The decrease of negatively charged antibodies is due to the p-type Ti3C2T x It is explained by recombination in MXene. Like a p-type semiconductor, Ti3C2T x The output curve of the / L-cysteine / anti-AFB antibody sensor is I ds increases negatively, and V g It shows a tendency to increase in a negative direction, and this tendency proves not only the functionalization but also the fixation of the field effect transistor.

[0103] Additionally, the surface functionalization of the field effect transistor (FET) of each sensor was analyzed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), which are based on changes in the interface characteristics of the electrodes.

[0104] Each FET sensor was fixed to a glassy carbon electrode (GCE) and Ti3C2T x / GCE, L-cysteine / Ti3C2T x / GCE and anti-AFB1 antibody / L-cysteine / Ti3C2T x / Produced with GCE and 10.0 mM K3[Fe(CN)6] 3- / 4-Cyclic voltammetry (CV) was measured in PBS (pH 7.4) containing 0.1 μg mL -1 In the presence of AFB1 (aflatoxin B1) (Ti3C2T x The CV value of / L-cysteine / anti-AFB1 antibody / analyte was also measured. As shown in Fig. 4(a), Ti3C2T x / Ti3C2T compared to GCE x / L-cysteine / GCE showed a tendency for the redox couple currents of 0.59 V and 0.33 V to decrease significantly. This was due to the electrode and K3[Fe(CN)6] 3- / 4- This may be due to the high electron mobility between the solutions. The reduced current is interpreted as a result of the L-cysteine ​​layer blocking the transfer of inert electrons, hindering the diffusion of redox couples to the electrode surface. Ti3C2T x / Ti3C2T compared to L-cysteine x In the case of / L-cysteine / anti-AFB1 antibody, the redox couple current was also significantly reduced, and when AFB1 was added (Ti3C2T x / L-cysteine / anti-AFB1 antibody / analyte) also showed a significant decreasing trend. This is interpreted as the electronic communication between the electrode and the redox probe was blocked as the antibody-AFB1 complex layer was formed. In addition, as shown in (b) of Fig. 4, the results of EIS (electrochemical impedance spectroscopy) analysis showed that Ti3C2T x The sensor is measured at 259 Ω, Ti3C2T x / L-cysteine ​​sensor was measured at 4417 Ω, while Ti3C2T xThe / L-cysteine / anti-AFB1 antibody sensor showed a significant increase in electron transfer resistance to 5985 Ω. Ti3C2T x When AFB1 was added to the / L-cysteine / anti-AFB1 antibody sensor, the resistance increased to 7828 Ω, which is interpreted as the formation of electrical insulation by the antibody-AFB1 complex.

[0105] From the above results, it was confirmed that AFB1 was effectively detected when the AFB1 antibody was immobilized on the MXene nanosheet functionalized with L-cysteine, and it was proven that the field effect transistor (FET) sensor according to the present invention can be used for the purpose of effectively detecting a target substance when an antibody that specifically binds to the target substance is immobilized.

[0106]

[0107] Example 4. Analysis of the effectiveness of mycotoxin detection using a FET sensor.

[0108] Using the fabricated FET sensor, the detection effect of AFB1 (aflatoxin B1) in an aqueous solution was analyzed, as shown in Fig. 5 (a). Distilled water was used as the medium, and the gate-source grounded terminals and drain-source current (I ds ) with a drain-source potential of 0.1 V (V ds ) was used to analyze the sensor signal. As shown in Fig. 5 (b), since the ultra-thin MXene nanosheet is a p-type semiconductor, the drain current of the sensing compartment was found to decrease instantaneously whenever a specific concentration of AFB1 was added.

[0109] The change in real-time drain-source current according to the concentration change of AFB1 was analyzed as a relative current response (%). The normalized current response is a sensor sensitivity index that determines the change in the device operation due to various factors of the channel material, such as thickness, distribution density, and composition. Initial I ds When I0 was set and AFB1 was added, the change in current was expressed as I - I0, and the relative response (%) was calculated as [(I - I0) / I0] X 100. As shown in Fig. 5 (c), the conductance of the FET sensor was clearly changed as the concentration range of AFB1 increased from 0 ppb to 80 ppb. In addition, when the concentration range of AFB1 was 0.7 ppb to 20 ppb, a high linear modulation (R 2 = 0.9202) was shown, confirming that quantitative analysis was possible, and the LOD (limit of detection) was analyzed to be 5.69 ppb, which is much lower than the maximum allowable limit for food of 10 ppb to 20 ppb.

[0110] To compare the functionality of the FET sensor, AFB1 at the same concentration was analyzed by HPLC. As shown in Figure 6, no peak was detected below 0.35 ppb in the HPLC analysis, and AFB1 peaks were observed at concentrations between 0.7 ppb and 100 ppb. The maximum recovery of AFB1 in the sample was 98.4 ± 0.2%. These results demonstrate that the EHD printed FET sensor according to the present invention is suitable for quantitative detection of small molecules at lower concentrations than HPLC analysis.

[0111]

[0112] Example 5. Evaluation of selectivity and stability of FET sensors

[0113] In the above Example 4, it was demonstrated that the FET sensor manufactured according to the present invention detected AFB1 with high sensitivity because it included an antibody against AFB1. In order to evaluate the selectivity and stability of the FET sensor, tests were conducted with mycotoxins other than aflatoxin B1 (AFB1), such as aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2), zearalenone (ZEA), and ochratoxin A (OTA). The test was conducted under the same conditions as in the above Example 4, and the concentration of the mycotoxin used was 1 ppb. As shown in (d) and (e) of Fig. 5, when zearalenone (ZEA), ochratoxin A (OTA), aflatoxin G2 (AFG2), aflatoxin G1 (AFG1), and aflatoxin B2 (AFB2) were added, the sensor signal was weakly detected, whereas aflatoxin B1 (AFB1) at the same concentration showed a high conductance change. The sensor conductance for each mycotoxin was 5.2% for zearalenone (ZEA), 5.9% for ochratoxin A (OTA), 9.4% for aflatoxin G2 (AFG2), 37.2% for aflatoxin G1 (AFG1), and 43.7% for aflatoxin B2 (AFB2), indicating relatively low detection performance. AFB1 showed a high conductance difference, which demonstrates that electrons moved to the sensing channel and the number of holes present within the sensing channel decreased. The excellent selectivity of the FET sensor according to the present invention was proven as it was confirmed that the above FET sensor exhibited significantly higher sensitivity to AFB1 compared to other mycotoxins.

[0114] The stability of the EHD printed FET sensor was monitored for detection performance against AFB1 in the same manner as described above after the sensor was stored at room temperature for 21 days. As shown in Fig. 7, the FET sensor was confirmed to exhibit a detection capability of over 93% even after 21 days of storage.

[0115] From the above results, it was confirmed that the EHD printed FET sensor according to the present invention not only selectively detects AFB1, but also maintains the detection ability of the sensor without decreasing during long-term storage, and it was proven that the field effect transistor (FET) sensor according to the present invention not only selectively detects a target substance depending on the immobilized antibody, but also has stability that maintains its performance during long-term storage.

[0116]

[0117] Example 6. DFT simulation

[0118] To verify the results of Example 5 above, density functional theory (DFT) simulations were performed to determine the binding of AFB1 (aflatoxin B1) and L-cysteine ​​molecules to Ti3C2F2MXene, Ti3C2O2 or Ti3C2(OH)2 according to the MXene surface functional groups, in terms of adsorption energies (E ads ) was analyzed. As the negative value of the adsorption energy increases, the interaction structure tends to be more stable, as shown in Fig. 8. As shown in Fig. 8, E of AFB1 for Ti3C2F2MXene and Ti3C2O2MXene adswere measured as 2.361 eV and -2.350 eV, respectively. The adsorption energy of Ti3C2(OH)2MXene and AFB1 was -8.529 eV, which was much lower than the adsorption energies of -F-, -O-, and -OH- functional groups and L-cysteine. In other words, it was demonstrated that the L-cysteine ​​layer acts as an electron transfer barrier for AFB1 on the MXene surface.

[0119]

[0120] Example 7. Detection of mycotoxins using a FET sensor (artificially contaminated peanut butter)

[0121] The ability of the EHD printed FET sensor according to the present invention to detect mycotoxins in food samples artificially contaminated with mycotoxins was evaluated. As shown in Fig. 9 (a), peanut butter with arbitrarily added AFB1 was used as an artificially contaminated sample. 100 ppb of AFB1 was added to the peanut butter and briefly homogenized in 80% methanol. The presence of the added AFB1 was examined by HPLC, as shown in Fig. 9 (c). As shown in Fig. 9 (b), the EHD printed FET sensor responded appropriately to AFB1 at various diluted concentrations ranging from 1 ppb to 10 ppb, and the response plot exhibited a linear pattern. These results demonstrate the potential of the EHD printed FET sensor for mycotoxin detection.

[0122]

[0123] Example 8. Detection of mycotoxins using a FET sensor (artificially contaminated meju)

[0124] The ability of the EHD printed FET sensor according to the present invention to detect mycotoxins in food samples contaminated with mold was evaluated. As shown in Fig. 10(a), meju contaminated with Aspergillus flavus was used as a sample. The meju sample (traditional Korean fermented soybean paste starter) was homogenized with methanol and then filtered to prepare an analytical sample. The presence of AFB1 was examined by HPLC, and the AFB1 produced by Aspergillus flavus contaminated in the meju was measured to be 20 ppb. As shown in Fig. 10(b), the EHD printed FET sensor clearly distinguished between the meju sample and the normal sample. The EHD printed FET sensor detected a 1 × 10 4 It responded well to the meju sample cultured by contaminating it with A. flavus spores, and the normalized response curve of the EHD printed FET sensor was linear.

[0125] From the above results, it was proven that the EHD printed FET sensor according to the present invention accurately detects AFB1 when applied to a food sample, and it was proven that the field effect transistor (FET) sensor according to the present invention can be utilized to detect mycotoxins contaminated in food.

[0126]

[0127] While specific aspects of the present invention have been described in detail above, it should be apparent to those skilled in the art that these specific descriptions merely represent preferred embodiments and are not intended to limit the scope of the present invention. In other words, the substantial scope of the present invention is defined by the appended claims and their equivalents.

[0128] Numerical ranges are inclusive of the values ​​defined in the ranges above. Any maximum numerical limitation given throughout this specification includes any lower numerical limitation, as if that lower numerical limitation were explicitly stated. Any minimum numerical limitation given throughout this specification includes any higher numerical limitation, as if that higher numerical limitation were explicitly stated. Any numerical limitation given throughout this specification will include any better numerical range within the broader numerical range, as if that narrower numerical limitation were explicitly stated.

Claims

1. Ti3C2T x A composite for a field effect transistor comprising MXene nanosheets having a composition, L-cysteine, and an antibody.

2. In the first paragraph, the MXen nanosheet is 1 mg mL -1 5 mg mL -1 A composite for a field effect transistor characterized by being manufactured in a two-dimensional layered structure by electrohydrodynamic jet-printing (EHD jet-printing) of MXene ink having a high concentration.

3. A composite for a field effect transistor, characterized in that the two-dimensional layered structure of the MXene nanosheet in the second paragraph has 200 to 400 layers.

4. In the first paragraph, the Ti3C2T x In the composition above T x A composite for a field effect transistor characterized in that the surface functional group of the MXene nanosheet is fluorine (F) or oxygen (O).

5. A complex for a field effect transistor, characterized in that in the first paragraph, the complex is coated with the L-cysteine ​​on the surface of the MXene nanosheet, and the antibody is bound to the L-cysteine ​​coating layer.

6. A complex for a field effect transistor, characterized in that the antibody in the first paragraph is an antibody that specifically binds to a fungal toxin.

7. A complex for a field effect transistor, characterized in that in paragraph 6, the mycotoxin is at least one mycotoxin selected from aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, zearalenone, and ochratoxin A. 8.Ti3C2T x A field effect transistor comprising a composite comprising MXene nanosheets having a composition, L-cysteine, and an antibody; a substrate; and a microelectrode.

9. A field effect transistor according to claim 8, wherein the substrate is composed of a p-type Si / SiO2 wafer and is coated with chromium (Cr) and gold (Au).

10. A field effect transistor according to claim 8, wherein the drain electrode and the source electrode in the microelectrode are made of high-purity gold and have a spacing of 3 μm.

11. Ti3C2T from MAX powder with Ti3AlC2 composition using aluminum etching method x Step for manufacturing MXene ink having a composition (Step 1); A step (second step) of manufacturing an MXene nanosheet by electrohydrodynamic jet-printing (EHD jet-printing) the MXene ink on a substrate between a drain electrode and a source electrode in a field effect transistor device; A step (third step) of immersing a device including the MXene nanosheet in an L-cysteine ​​solution to coat the surface of the MXene nanosheet with the L-cysteine; Step 4: treating the device coated with L-cysteine ​​with a catalyst for inducing peptide bonds; and A method for manufacturing a device for a field effect transistor for target material analysis, comprising a step (step 5) of treating the device of the above-mentioned step 4 with an antibody that specifically binds to the target material and fixing the antibody to an L-cysteine ​​coating layer.

12. A method for manufacturing a device for a field effect transistor for target material analysis, characterized in that in the 11th paragraph, MXene ink is manufactured by ultrasonic treatment of an MXene sheet obtained after etching MAX powder having a Ti3AlC2 composition in the first step.

13. In the 11th paragraph, the second step is performed so that the concentration of the MXene ink is 1 mg mL -1 5 mg mL -1 A method for manufacturing a device for a field effect transistor for target material analysis, characterized in that the method is performed under conditions in which the flow rate of the MXene ink is 0.45 μL / min, the working distance between the printing nozzle and the substrate is 600 μm, and the printing speed is 100 mm / mL.

14. A method for manufacturing a device for a field effect transistor for target material analysis, characterized in that in the fourth step, the catalyst for inducing peptide bonds is at least one catalyst selected from among 1-ethyl-3-(3-dimethylamino) propyl carbodiimide hydrochloride and N-hydroxysuccinimide.

15. A method for manufacturing a device for a field effect transistor for target material analysis, characterized in that the fifth step in the 11th paragraph is performed at a temperature of 25°C to 37°C.

16. A step of preparing an analysis sample by adding an aqueous solution to a food sample; A step of applying the analysis sample to a device for a field effect transistor for target material analysis manufactured according to the manufacturing method of any one of claims 11 to 15; and A method for analyzing the safety of a food sample, comprising a step of measuring an electrical signal of a device for the field effect transistor to determine whether the target substance exists in the food sample.

17. A method for analyzing the safety of a food sample, characterized in that, in the 16th paragraph, when the target substance is a mycotoxin, the antibody included in the field effect transistor device is an antibody that specifically binds to the mycotoxin.

18. A method for analyzing the safety of a food sample, characterized in that in paragraph 17, the mycotoxin is at least one mycotoxin selected from aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, zearalenone, and ochratoxin A.

19. In the 16th paragraph, the electrical signal is characterized in that it is calculated by the following mathematical formula 1 by measuring the drain-source potential of the field effect transistor device: [Mathematical Formula 1] ΔI / I0(%)= [(I - I0) / I0] Here, I is the current detected in real time when the above analysis sample is applied, I0 is the initial current before the above analysis sample is applied, and ΔI represents the current change.

20. In paragraph 19, the analysis method is: A step of applying a standard sample of a target material to the device for the field effect transistor to create a calibration curve for the electrical signal (ΔI / I0(%)) according to the concentration of the target material; and A method for analyzing the safety of a food sample, further comprising a step of measuring the concentration of the target substance contained in the analysis sample using the calibration curve.

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