Detection Of Acetamiprid And Profenofos With The Label Free Fluorescent Aptasensors In Fruit And Vegatebles

Based on the current status of agricultural development,the use of pesticides for the development of agriculture can be described as its industrial revolution.The use of pesticides not only can solve the problems caused by pests and diseases,but also can increase the yield of food and vegetables.However,with the continuous increase with the use of pesticides,a series of negative effects are being brought,such as pollution of water and the environment,affecting human health.Therefore,the pesticide residue detection technology is gradually developed and known as one of the key technologies of food safety testing.Nucleic acid aptamers are more and more used as recognition elements in the construction of sensors because of their excellent specificity,high affinity and wide application range.As an identification element,the Triple-helix Molecular Switch(THMS)has the advantages of good versatility,strong stability and structural characteristics;and as a kind of rare earth elements,Tb3+has the sensitization characteristics that has been found and used gradually.In this paper,the detection of pesticide residues in vegetables and fruits as the main goal,the nucleic acid aptamers and triple helix DNA molecules and rare earth elements Tb3+ are combined to build two label free fluorescent nucleic acid aptamer sensors in order to achieve efficient and sensitive determination of the target substances.The main contents of the study are as follows:(1)Based on the nucleic acid aptamer of triple helix DNA molecule switch,the detection system of acetamiprid detection was established.With the novel triple helix DNA molecule switch as the starting point,combine the synergistic effect of triple helix DNA,good stability,structure and specificity of the characteristics of nucleic acid aptamer to achieve the efficient and rapid determination of the target acetamidine by fluorescence analysis.Under the optimal experimental parameters,the linear range of the target is 1-12?M(final concentration of 100-1200nM)and the detection limit is 9.12 nM.The experimental method is fast,efficient,sensitive,reproducible,and can meet the need of rapid screening of pesticide residues.At the same time,this new method of constructing a new sensing method for the detection of pesticide residues in food can provide a reference for the establishment of other methods for rapid detection of small molecule harmful substances using the aptamers as recognition elements,and spread the application of aptamer structure switch.(2)Based on the specificity of Tb3+ sensitized fluorescent nucleic acid aptamer sensor,an experimental system for the detection of profenofos was established.Tb3+ sensitized fluorescent nucleic acid was constructed by using Tb3+ as a fluorescent agent,using the luminous signal characteristics of rare earth element Tb3+.Single-stranded DNA in the guanine base pairs of Tb3+ fluorescence enhancement,as well as the specificity of nucleic acid aptamer recognition ability are used to sensitively detect bromine phosphorus.Under the optimal experimental conditions,the linear range of bromine phosphorus is 1-12?M(final concentration of 100-1200nM)and the detection limit is 0.105?M.The experimental method has the advantages of high efficiency,sensitivity and specificity,and can meet the rapid determination of target profenofos.At the same time,the combination of luminous properties of Tb3+ and nucleic acid aptamer is of great significance for the application and research of rare earth ions.