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CN-121994888-A - Ti (titanium)3C2MXene sensitized paper-based electrochemical aptamer sensor and preparation method and application thereof

CN121994888ACN 121994888 ACN121994888 ACN 121994888ACN-121994888-A

Abstract

The invention discloses a Ti 3 C 2 MXene sensitized paper-based electrochemical aptamer sensor and a preparation method and application thereof, belonging to the technical field of electrochemical sensing and biological detection. The sensor comprises a paper-based substrate, a three-electrode system and a three-electrode system, wherein the paper-based substrate is provided with a hydrophilic electrode area defined by a hydrophobic isolation belt, the three-electrode system is printed in the hydrophilic electrode area and comprises a working electrode, a counter electrode and a reference electrode, the working electrode and the counter electrode are made of carbon black/carbon nano tube/Ti 3 C 2 MXene ternary composite conductive ink, the ink comprises a conductive active substance, polydimethylsiloxane (PDMS) base adhesive and a curing agent, and the surface of the working electrode is sequentially modified with a gold nano particle layer, an AFB1 specific aptamer layer and a 6-mercaptoethanol sealing layer from bottom to top. The sensor is suitable for high-sensitivity and low-cost specificity detection of aflatoxin B1 (AFB 1), the detection accuracy of AFB1 pollutants in food based on the sensor is improved from 89% to 95%, and the industrialization prospect is good.

Inventors

  • WANG CHENGQUAN
  • ZHANG CHENHAO
  • QIAN JING
  • DENG TAO

Assignees

  • 江苏大学

Dates

Publication Date
20260508
Application Date
20260312

Claims (9)

  1. 1. A Ti 3 C 2 MXene sensitized paper-based electrochemical aptamer sensor is characterized by comprising A paper-based substrate having a surface with a hydrophilic electrode area defined by a hydrophobic separator; A three-electrode system printed in the hydrophilic electrode region and comprising a working electrode, a counter electrode and a reference electrode; The working electrode and the counter electrode are made of carbon black/carbon nano tube/Ti 3 C 2 MXene ternary composite conductive ink, wherein the ink comprises a conductive active substance, polydimethylsiloxane (PDMS) base adhesive and a curing agent; The surface of the working electrode is sequentially modified with a gold nanoparticle layer, an AFB1 specific aptamer layer and a 6-mercaptoethanol sealing layer from bottom to top. The AFB1 specific aptamer is a PolyA modified aptamer, and the sequence of the aptamer is 5'-AAAAAAAAAAGTT GGG CAC GTG TTG TCT CTC TGT GTC TCG TGC CCT TCG CTA GGC CCA CA-3'.
  2. 2. The Ti 3 C 2 MXene sensitized paper-based electrochemical aptamer sensor of claim 1, wherein the preparation raw materials of the carbon black/carbon nano tube/Ti 3 C 2 MXene ternary composite conductive ink comprise CNTs, ti 3 C 2 MXene, carbon black, PDMS base gum, a curing agent, N-methylpyrrolidone, sodium dodecyl benzene sulfonate, ascorbic acid and absolute ethyl alcohol, and the mass ratio of the PDMS base gum to the curing agent is 10:1.
  3. 3. A method for preparing the Ti 3 C 2 MXene sensitized paper-based electrochemical aptamer sensor according to any one of claims 1 to 2, comprising the following steps: Step 1, preparing carbon black/carbon nano tube/Ti 3 C 2 MXene ternary composite conductive ink; Step 2, performing hydrophobic patterning treatment on the paper-based substrate, printing the ternary composite conductive ink prepared in the step 1 on the exposed area of the paper-based substrate, preparing a reference electrode by dripping Ag/AgCl slurry after curing, and removing the hydrophobic material to obtain a paper-based three-electrode system; Step 3, depositing gold nano particles on the surface of the working electrode by adopting an electrochemical deposition method; Step 4, the AFB1 specific aptamer working solution is dripped on the surface of the gold nanoparticle modified working electrode, and free aptamer is removed by flushing after incubation; And 5, dripping MCH solution on the surface of the working electrode, and washing to remove free MCH after incubation to obtain the electrochemical aptamer sensor.
  4. 4. The method for preparing the Ti 3 C 2 MXene sensitized paper-based electrochemical aptamer sensor according to claim 3, wherein in the step 1, the specific preparation process of the ternary composite conductive ink is as follows: (1) CNTs pretreatment, namely adding CNTs into a mixed solution of NMP and SDBS, ultrasonically dispersing for 1 h, centrifuging, and taking supernatant for later use; (2) Ti 3 C 2 MXene pretreatment, namely dispersing Ti 3 C 2 MXene in absolute ethanol containing 0.1% ascorbic acid under the protection of nitrogen, and carrying out ultrasonic treatment on the mixture for 30: 30 min to prepare Ti 3 C 2 MXene dispersion; (3) Adding carbon black into Ti 3 C 2 MXene dispersion liquid, magnetically stirring 1: 1h, adding pretreated CNTs supernatant, and magnetically stirring 2: 2h to obtain composite dispersion liquid; (4) And (3) conducting ink molding, namely adding PDMS base gel and a curing agent into the composite dispersion liquid, and magnetically stirring for 30 min to prepare the ternary composite conducting ink.
  5. 5. The preparation method of the Ti 3 C 2 MXene sensitized paper-based electrochemical aptamer sensor according to claim 3 is characterized in that in the step 2, hydrophobic patterning treatment is carried out by adopting a hydrophobic adhesive tape for attaching, the conductive ink is repeatedly printed for 2 times, a space between two times of printing is 10 min, the conductive ink is naturally dried at room temperature and then is placed in an 80 ℃ oven for curing 1h, and the Ag/AgCl slurry is placed in the 80 ℃ oven for drying 10 min after being dripped.
  6. 6. The method for preparing a Ti 3 C 2 MXene sensitized paper-based electrochemical aptamer sensor according to claim 3, wherein in the step 4, the concentration of the AFB1 specific aptamer working solution is 1.2 mu M, the working solution is prepared by adopting TE buffer solution, the TE buffer solution is 50 mM Tris-HCl buffer solution and contains 1.0 mM EDTA, 5.0 mM MgCl 2 , 0.1M NaCl and 0.2M KCl, pH=7.4, and the incubation condition is that the incubation is 12h under room temperature.
  7. 7. The method for preparing the Ti 3 C 2 MXene sensitized paper-based electrochemical aptamer sensor according to claim 3, wherein in the step 5, the incubation condition of the MCH solution is that the incubation is 0.5-1 h at room temperature, and the TE buffer solution is adopted for flushing, wherein the TE buffer solution is 50mM Tris-HCl buffer solution and contains 1.0 mM EDTA, 5.0 mM MgCl 2 , 0.1M NaCl, 0.2M KCl and pH=7.4.
  8. 8. An application of the Ti 3 C 2 MXene sensitized paper-based electrochemical aptamer sensor based on any one of claims 1-2 is characterized in that the application is trace screening and quantitative detection of AFB1 in food, and detection is carried out by adopting an electrochemical impedance method, and the method specifically comprises the following steps: (1) The detection pretreatment comprises the steps of dripping a sample solution to be detected or AFB1 standard solutions with different concentrations on the surface of a working electrode of a sensor, incubating at 37 ℃ for 1h, and flushing with TE buffer solution to remove unbound free AFB1; (2) EIS detection, namely placing the washed sensor in impedance detection liquid, and detecting EIS signals of a working electrode by adopting an electrochemical workstation, wherein the detection parameters are that the test frequency range is 0.1 Hz-10 kHz, the amplitude of alternating current signals is 5 mV, the impedance detection liquid is 0.1M PBS buffer solution (pH=7.4), and the impedance detection liquid contains 5.0 mM [ Fe (CN) 6 ] 3- / 4- redox pair and 0.1M KCl; (3) And (3) quantitatively detecting, namely establishing a standard working curve by taking the concentration of the AFB1 standard solution as an abscissa and the corresponding EIS impedance characteristic value as an ordinate, and calculating to obtain the concentration of the AFB1 in the sample to be detected according to the impedance characteristic value of the sample to be detected and the standard working curve.
  9. 9. The application of the kit according to claim 8, wherein the concentration range of the AFB1 standard solution is 0.01-100 ng/mL, and the sample to be detected is any one of grains, oil, dairy products and seasonings, or an intermediate product and a finished product in the food processing process.

Description

Ti 3C2 MXene sensitized paper-based electrochemical aptamer sensor and preparation method and application thereof Technical Field The invention belongs to the technical field of electrochemical sensing and biological detection, and particularly relates to a Ti 3C2 MXene sensitized paper-based electrochemical aptamer sensor, a preparation method and application thereof. Background Mycotoxins are widely used in crops, foods and feeds, and seriously threaten human health and animal growth, wherein aflatoxin B1 (AFB 1) has strong carcinogenicity and wide pollution range, and becomes a key point for detecting mycotoxins. The rapid, accurate and low-cost detection of the AFB1 is realized, and the method is important for guaranteeing the food safety. The existing AFB1 detection method (such as high performance liquid chromatography and fluorescence spectrophotometry) has high accuracy, but has the disadvantages of expensive equipment, complex operation and long detection period, and can not meet the requirements of on-site rapid detection and base layer screening. The electrochemical sensor has the advantages of rapidness, sensitivity, low cost, simple operation and the like, and is widely applied to the field of mycotoxin detection, and the performance of the electrochemical sensor depends on electrode materials and identification elements. The nano material can obviously optimize the performance of the sensor, wherein the Carbon Nanotubes (CNTs) have excellent conductivity and stability, can improve the detection sensitivity, and can realize the high-specificity detection of the AFB1 by taking the aptamer as a specific recognition element. The current electrochemical sensor is mostly based on rigid electrodes such as glassy carbon electrodes, gold electrodes and the like, has the limitations of high cost, difficulty in disposable use, poor flexibility, complex preparation process and the like, and is not beneficial to large-scale popularization. The paper-based electrochemical sensor can solve the defect of the rigid electrode and becomes a research hot spot, but the existing conductive materials of the paper-based electrode are mostly single or simple composite systems, so that the conductivity, the flexibility and the biocompatibility are difficult to be considered, the high-sensitivity detection requirement of the AFB1 cannot be met, and the industrialization application of the paper-based electrochemical sensor is limited. Therefore, developing a paper-based electrochemical aptamer sensor with high conductivity, good flexibility, excellent biocompatibility and low cost for AFB1 high-sensitivity detection is a technical problem to be solved in the art. Disclosure of Invention The invention aims to overcome the defects of the prior art, provides a Ti 3C2 MXene sensitized paper-based electrochemical aptamer sensor and a preparation method and application thereof, relates to a paper-based electrochemical aptamer sensor for constructing ternary composite conductive ink by carbon black, carbon Nanotubes (CNTs) and Ti 3C2 MXene, is suitable for high-sensitivity and low-cost specific detection of aflatoxin B1 (AFB 1), and simultaneously relates to the fields of conductive ink formula optimization, sensor preparation process and electrochemical detection method, cross-domain biosensing science, electrochemical analysis technology and flexible functional material preparation. After condition optimization, the detection accuracy of AFB1 pollutants in food based on the sensor disclosed by the invention is improved from 89% to 95%. The invention provides a Ti 3C2 MXene sensitized paper-based electrochemical aptamer sensor, which comprises a paper-based substrate, wherein the surface of the paper-based substrate is provided with a hydrophilic electrode area defined by a hydrophobic isolation belt, a three-electrode system is printed in the hydrophilic electrode area and comprises a working electrode, a counter electrode and a reference electrode, wherein the working electrode and the counter electrode are made of carbon black/carbon nano tube/Ti 3C2 MXene ternary composite conductive ink, the ink comprises a conductive active substance, polydimethylsiloxane (PDMS) base gum and a curing agent, a gold nano particle layer, an AFB1 specific aptamer layer and a 6-mercaptoethanol sealing layer are sequentially modified on the surface of the working electrode from bottom to top, and the AFB1 specific aptamer is a Poly A modified aptamer, and the sequence of the AFB1 specific aptamer is 5'-AAAAAAAAAAGTT GGG CAC GTG TTG TCT CTC TGT GTC TCG TGC CCT TCG CTA GGC CCA CA-3'. Further, the preparation raw materials of the carbon black/carbon nano tube/Ti 3C2 MXene ternary composite conductive ink comprise Carbon Nano Tubes (CNTs), ti 3C2 MXene, carbon black, PDMS base gum, a curing agent, N-methylpyrrolidone (NMP), sodium Dodecyl Benzene Sulfonate (SDBS), ascorbic acid and absolute ethyl alcohol, wherein the mass ratio of the PDMS base g