Design of a facile and highly sensitive electrochemical impedimetric aptasensor for detection of 17β-estradiol

Abstract

In this work, a facile, rapid and label-free electrochemical (EC) impedimetric aptasensor was developed for detecting 17β-estradiol (E2) based on gold particles (Au NPs) signal amplification. The aptamer was used as the recognition and capture unit to label on the surface of Au NPs. The anti-E2 aptamer labelled Au NPs (apt-Au NPs) were then anchored on the complementary DNA-immobilized gold electrode surface by hybridization. Owing to the large surface, good biocompatibility and high conductivity, Au NPs can not only provide a wonderful microenvironment for aptamer, but also play a signal amplification role, improve analytical performance of the EC sensing platform. Due to the high affinity and specificity of aptamer to E2, the formed aptamer-E2 complexes with poor conductivity increase the electron transfer resistance (Ret). Quantitative analysis for E2 was performed based on the correlation between the change of the Ret and E2 concentrations. The developed sensor exhibited excellent analytical performance with high sensitivity, selectivity and good stability for the detection of E2. The detection limit for E2 is 0.053 pM, with a linear response ranging 0.1–200 pM. Meanwhile, its application in real environmental samples was evaluated and satisfying results were achieved.