▎ 摘　　要

NOVELTY - Constructing aptamer sensor based on terminal deoxynucleotidyl transferase (TdT) and G-quadruplex (G4)/hemin simulation enzyme amplification technology, involves (a) obtaining tin indium octathiocane-GR (SnIn4S8-GR), (b) obtaining gold nanoparticles-doped SnIn4S8-GR through centrifugation, (c) obtaining the MBs-Apt solution, (d) preparing the ultrapure aqueous solution of gold nanoparticles-doped SnIn4S8-GR obtained in step (b), and drop-coating on the surface of the indium tin oxide electrode, (e) dispersing the MBs-Apt-P1 of step (c) in the PBS solution, adding the standard solutions of ampicillin, shaking, dripping the supernatant onto the surface of the detection electrode, dripping TdT buffer, deoxyadenosine triphosphate (dATP) solution and deoxyguanosine triphosphate (dGTP) solution, obtaining G-rich single strand (ss)DNA, and forming G4/hemin on the detection electrode, and (f) obtaining the working curve of the ampicillin standard solution. USE - The method is useful for constructing aptamer sensor based on TdT and G4/hemin simulation enzyme amplification technology, where the aptamer sensor is used in detecting ampicillin content in the detection sample of non-disease diagnosis purpose (claimed), and used for environment monitoring and biological analysis. ADVANTAGE - The aptamer sensor has high sensitivity, high stability, high selectivity, and high application prospect in biological analysis and environment monitoring. DETAILED DESCRIPTION - Constructing aptamer sensor based on terminal deoxynucleotidyl transferase (TdT) and G-quadruplex (G4)/hemin simulation enzyme amplification technology, involves (a) dispersing graphene oxide (GO) in ultrapure water, adding acetic acid solution of tin(IV) chloride pentahydrate, sequentially adding indium(III) chloride tetrahydrate and sodium dodecylbenzene sulfonate (SDBS), after ultrasonic stirring, adding thioacetamide (TAA), after stirring, pouring into the reactor, reacting to completeness, after cooling to room temperature, centrifuging, washing and drying to obtain tin indium octathiocane-GR (SnIn4S8-GR), (b) dissolving the SnIn4S8-GR of step (a) in ultrapure water, adding sodium citrate solution, stirring and heating to boiling, rapidly adding chloroauric acid, turning off the heat source after continuously boiling, continuously stirring and cooling to room temperature, and obtaining gold nanoparticles (NPs)-doped SnIn4S8-GR through centrifugation, washing and drying, (c) magnetically separating the magnetic beads (MBs), washing three times with phosphate-buffered saline (PBS) solution, adding to PBS solution dissolved with N-hydroxysuccinimide (NHS) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), washing with PBS solution after shaking activation, adding the aptamer (Apt) solution, shaking the solution overnight, after reacting, obtaining the MBs-Apt solution by magnetic separation, mixing with P1 solution, shaking overnight, and obtaining MBs-Apt-P1 after magnetic separation and washing, (d) preparing the ultrapure aqueous solution of gold nanoparticles-doped SnIn4S8-GR obtained in step (b), drop-coating on the surface of the indium tin oxide (ITO) electrode, drying under infrared light, dropping the S1 solution onto the surface of the dried ITO electrode, incubating overnight, and washing with Tris-hydrochloric acid buffer to remove excess S1 to obtain a pretreated electrode, (e) incubating the pretreated electrode of step (d) in the methylcyclohexane (MCH) solution to obtain the detection electrode, simultaneously dispersing the MBs-Apt-P1 of step (c) in the PBS solution, adding the standard solutions of ampicillin with different concentrations, after shaking, dripping the supernatant onto the surface of the detection electrode, dripping TdT solution, TdT buffer, deoxyadenosine triphosphate (dATP) solution and deoxyguanosine triphosphate (dGTP) solution after incubation, after mixing, incubating to obtain G-rich single strand (ss)DNA, adding hemin solution after washing, and forming G4/hemin on the surface of the detection electrode after incubation in the dark, and (f) dripping 4-cyanide (CN) solution and hydrogen peroxide solution to the surface of the detection electrode treated in step (e), incubating at room temperature, detecting the photocurrent value in the PBS solution containing acrylic acid (AA), and establishing the quantitative relationship between the photocurrent value and the concentration of ampicillin, to obtain the working curve of the ampicillin standard solution. An INDEPENDENT CLAIM is also included for use of the aptamer sensor constructed by the above method in detecting ampicillin content in the detection sample of non-disease diagnosis purpose, involving repeating the operations of steps (a)-(f), replacing the ampicillin standard solution of different concentrations in step (e) with the sample solution, and substituting the measured photocurrent value into the working curve to calculate the ampicillin content in the sample.