Using Simple-Structured Split Aptamer for Gold Nanoparticlebased Colorimetric Detection of Estradiol

Abstract

Demand for the detection of estradiol, which is a naturally occurring hormone, has been increasing. Gold nanoparticlebased colorimetric aptasensors have been developed for estradiol detection; however, the long sequence of aptamers due to the formation of the secondary structure likely affects the sensitivity of the aptasensors. Herein, a sensitive colorimetric biosensor is developed for label-free detection of estradiol by using an estradiol-specific split aptamer. The results demonstrate that a superior response is observed when a split aptamer with a high free energy of the secondary structure (∆G > -3 kcal/mol) is used, in comparison to that observed using a split aptamer with a low free energy of the secondary structure (∆G