Quenched Electrochemical Biosensor Based on Adsorption Between GO and Aptamer for the Detection of ERα

Abstract

Breast cancer is one of the three most common cancers in the world, and is the most prevalent malignancy in women. Estrogen receptor alpha (ERα), an important marker for early diagnosis of breast cancer, shows positivity in more than 75% of breast cancers. Herein, a quenched electrochemical biosensor based on the adsorption interaction between graphene oxide (GO) and aptamer (Apt) and the ATRP signal amplification strategy for sensitive detection of ERα was constructed. The Apt was immobilized on the electrode surface by gold-sulfur bonding and adsorbed GO-BIBB by π–π stacking. In the ATRP reaction solution, ferrocene polymerized on the electrode surface in the presence of a catalyst and initiator and generated electrochemical signal. After the addition of ERα, a large number of electrical signal molecules were shed from the electrode surface with GO, causing quenching of the signal. By optimizing the reaction conditions, the detection limit (LOD) of the biosensor can reach 0.17 pg·ml−1, and the logarithm of the current intensity and concentration shows a good linearity in the range of 1 pg·ml−1 to 100 ng·ml−1. The biosensor also has excellent selectivity, stability, interference resistance and reproducibility. More importantly, the biosensor enabled the detection of ERα in real samples.