Selection of chlorpyrifos-binding ssDNA aptamer by SELEX

This experiment aimed to select specific aptamer of chlorpyrifos by SELEX.With streptavidin agarose resinsn as carrier and chlorpyrifos as target,a synthetic DNA library with total length of 91 nt was subjected to selection using SELEX(Systematic evolution of ligands by exponential enrichment) technology.By fluorescent label technique,the selection efficiency,affinity and specificity of selected aptamer were investigated.The secondary structures of aptamers with higher affinities and their corresponding binding sites were predicted and analyzed by MFOLD software.The results showed that after 15 rounds in vitro selection,the efficiency of selection could reach 44.00%.Nine aptamers were successfully selected for their high abilities to bind chlorpyrifos,of which,aptamer N23 was the best for binding chlorpyrifos.The stem-loop of aptamer might work as the main motif in the interaction between aptamer and chlorpyrifos.