The Research Of A Graphene Oxide-based Aptasensor Used For The Detection Of Tetracycliner Esiduein In Food

Graphene oxide(GO)was got widely research because of excellent electrical,thermal stability,mechanical property and good chemical properties.Based on the properties of GO,it was widely used in biomedical,food analysis,gene diagnosis,therapy and bioimaging.Aptamer are artificial specific oligonucleotides,DNA or RNA,with the ability to bind to non-nucleic acid target molecules.GO can aggregate in saline solution,while aptamer has proven to interact with GO through ?-?stacking ability.Because of the strong binding ability between GO and aptamer,aptamer can protect GO from aggregation under salt conditions.Tetracycline antibiotics(TCs)are broad-spectrum antibiotics and widely used in veterinary medicine for prevention of diseases.But it is harmful to human health if TCs are found residue in food.So it is necessary to develop rapid,sensitive method for detection TC.A GO-based aptsensor assay for detection TC was developed in our article.(1)Synthesis of graphene oxide.In this work,GO was synthesized from natural graphite powder by a modified Hummers method.We used TEM,AFM,FT-IR,XRD,Raman to characterize the prepared GO.The TEM images show the wrinkles of GO.AFM image shows the single layers of GO with a thickness of around 1.3 nm.FT-IR spectroscopy shows most oxygen-containing groups exist on the surface of GO.The GO showed a typical optical absorption at 230 nm.The Raman spectrum of GO exhibited two prominent peaks at 1602.89 cm-1 and 1345.92 cm-1,which correspond to the well-documented G and D bands,respectively.The ID/IG ratio was 0.82.The XRD pattern of pure GO showed a strong peak at 20 = 11.8°.Besides,GO was also used to carry out quantitative analysis.It was proved that the higher degree of oxidation of GO.(2)GO-based aptsensors for detection TC in honey samples.The assay was designed based on the protection effect of the aptamer on GO due to aggregation.GO has good absorbance in 230 nm.When the GO-based aptasensor was incubated with TC,TC could capture the TC aptamer from GO,leading to the aggregation of GO in a high salt solution.A linear relationship between the optical response and the logarithm concentration of TC was observed after centrifugation.The detection range was 0.002 to 20 ng·mL-1 and the detection limit was 0.001 ng·mL-1.The recoveries of TC in honey samples(0.001 mg·kg-1,0.01 mg·kg-1 and 0.1 mg·kg-1)were from 82.5%to 117%.(3)The effect of DNase I to the GO-based aptsensors method to detect TC.DNase I enhanced the sensitivity of the method and the detection limit was 9.69×10-4 ng·mL-1.