Screening Of Nucleic Acid Aptamers Of Sodium Formaldehyde Sulfoxylate Based On SELEX And Its Application

As a result of the prompts of the market,there are still many illegal traders,using the food additives.Therefore,food safety is still a hot issue in today's society,and it is necessary to increase supervision and enforcement to solve this problem of food safety.About the additives,one is allowed to add but the amounts has explicit requirements,the other is strictly forbidden.Our market need a method which is fast,accurate and stable inspection of illegal food additives.Once the consumption eats food which were illegaled sodium formaldehyde fulfoxylate,it can cause allergies,intestinal irritation or other adverse reactions,even poisoning,kidney,liver damage or other diseases.In the national standard "food additives using health standards",hanging sodium formaldehyde fulfoxylate is excluded from the statutory food additives.In March 1988,the relevant departments of the State Council have explicitly denied the use of illegal additives in grain and oil food.Therefore,the development of meyhod about fast detection of sodium formaldehyde fulfoxylate in food need to be resolved.Firstly,a screening study was carried out on the identification of aptamer-specific aptamers based on the SELEX method.For screening the nucleic acid aptamer of the sodium formaldehyde fulfoxylate,the sodium formaldehyde fulfoxylate were conjugated to the epoxy-activated sepharose 6B as a target molecule,and incubate with a random library in vitro synthesis.After 10 rounds of SELEX screening,the final product were purified,cloned,and sequenced.Stem ring and G-quadruplex structure were the main structure of secondary structure.By the circular dichroism,the nucleic acid aptamers do not affect structure in potassium ion solution.Demonstrating the possibility that the nucleic acid aptamer can specifically binds with sodium formaldehyde fulfoxylate.In this paper,an enzyme-linked oligonucleotide(ELONA)method was builded,which was used to verify the high affinity and strong specificity of the nucleic acid aptamers.Respectively the aptamers of Sfs-A09,SFs-B09 and Sfs-E07 dissociation constants were 39.81±11.78 nM,47.89±12.73 nM and 61.12±16.36 nM.Three kinds of nucleic acid aptamers have a good ability to identify suspended sodium formaldehyde fulfoxylate.The selected nucleic acid aptamer was used to detect in the actual toxin sample.Four kinds of sodium formaldehyde fulfoxylate concentrations(1 ng/mL?4 ng/mL?8 ng/mL?10 ng/mL)were added to the samples of tofu for simulation experiments.The recoveries were between 80.14%and 101.10%and it has a very good linear relationship.The final experiment of test strip simulation demonstrated that the possibility of applying three nucleic acid aptamers to detct the sodium formaldehyde fulfoxylate in the actual product.Three nucleic acid aptamers have good specificity and high sensitivity,especially the development of fast detection kits for sodium formaldehyde fulfoxylates in food.