Study On The Aptamer-Based Novel Methods For The Detection Of Cyromazine

Cyromazine is a triazine pesticide,which is widely used in animal husbandry as feed additives.It can enter the human body and have an impact on human health because it has migratory in the environment.Cyromazine can be metabolized into melamine through dealkylation in animals and plants.Long-term intake of melamine can cause kidney stones and renal failure.In 2008,melamine was widely concerned about the contaminated baby milk powder scandal,but cyromazine which is the metabolite of melamine was ignored.With the expansion of the scope of government testing,cyromazine has come into people’s eyes.Nowadays,before the derivative products are shipped from the factory,the residues of cyromazine and melamine in milk must be strictly tested according to national standards.Therefore,the detection of cyromazine in milk has become a hot topic,especially the rapid on-site inspection before leaving the factory.Traditional cyromazine detection methods such as high-performance liquid chromatography and gas chromatography-mass spectrometry.They are not suitable for rapid on-site detection due to the complex steps and high detection costs.Therefore,it has great theoretical value and practical significance to establish an efficient,rapid and economical detection method for test cyromazine.Aptamers have the advantages of easy synthesis,low cost,high specificity and sensitivity for binding targets.They have been widely used for the detection of various targets.Therefore,three different signal output technologies were developed for rapid cyromazine detection in milk based on Cyr-specific aptamers in this paper.A method for the rapid detection of cyromazine in milk was developed based on cyr-specific aptamers and fluorescence quenching.When an FAM labelled G-rich ss DNA Tcy2 is treated with cyromazine,it can form a G-quadruplex-CYR complex and cause a change in fluorescence.Under the optimal detection conditions,this method has a detection range from 0 to 200 ppb,and has a limit of detection of 0.68 ppb.A method for the rapid detection of cyromazine in milk was developed based on Cyr-specific aptamers and a colorimetric method.The aptamer can be adsorbed on the surface of AgNPs and electrostatically interact with Poly dimethyl diallyl ammonium chloride(PDDA),thereby protecting Au NPs from being aggregated.When cyromazine is added,it can form a G-quadruplex-CYR complex and the AgNPs were aggregated in the PDDA solution.The color of the solution changed from red to purple or even blue FOR the naked eyes.Under the optimal detection conditions,this method has a detection range from 0 to 1ppm,and has a limit of detection of 5.8ppb.A method for the rapid detection of cyromazine in milk was developed based on Cyr-specific aptamers and surface-enhanced raman spectroscopy.The aptamer can specifically bind to cyromazine and directly control the in situ reduction of nano-silver on the surface.At this time,the cyromazine-DNA / AgNPs complex can be formed and cause Raman enhancement effect.Under the optimal detection conditions,this method has a detection range from 0 to 0.5ppm,and has a limit of detection of 23.6ppb.